F.Y. Lee^1,2, I.Y. Zhou^1,2, S.J. Fan^1,2, A.Y. Ding^1,2, and E.X. Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong, China, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China

Sleep deprivation not only compromises alertness and cognitive performance, but also induces adverse effects in memory and emotional behaviors. In this study, we aim to employ high resolution MEMRI to probe in vivo neuronal changes following sleep deprivation. Significantly reduced Mn uptake was observed in the hippocampal region of the sleep deprived animals. In particular, the dentate gyrus exhibited the least Mn uptake, indicating its functional vulnerability to sleep deprivation.

Yuko Kawai¹, Masahiro Umeda¹, Yasuharu Watanabe¹, Toshihiro Higuchi², and Chuzo Tanaka^2
1Medical Informatics, Meiji University of Integrative Medicine, Kyoto, Japan, ²Neurosurgery, Meiji University of Integrative Medicine, Kyoto, Japan

�yIntroduction�zSpontaneous pain and allodynia are the common complaint in chronic pain conditions. The purpose of this study is to detect brain activation spontaneous pain using AIM MRI in a segmental spinal nerve ligation (SNL) model.�yMethods�z The right L5 spinal nerves were ligated with silk sutures. The AIM MRI were acquired using a 4.7-T MRI system.�yResults�zSpontaneous pain induced brain activation was successfully visualized using AIM MRI. Signal enhancement was observed in the contralateral side of the primary somatosensory area (S1) and ipsilateral side cingulate areas (Cg).

Yutong Liu^1,2, Adrian A Epstein², Aditya N. Bade², Howard E. Gendelman², and Michael D. Boska^1,2
1Department of Radiology, University of Nebraska Medical Center, Omaha, NE, United States, ²Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States

We investigated manganese (Mn) glial uptake in vitro and in vivo (rodents) to assess the roles of glia and neurons in MEMRI signal enhancement. PC 12 cells were co-cultured with activated astrocytes and microglia in the in vitro study. In-vivo, glial activation was induced by LPS injection. In vitro Mn uptake by PC 12 cells was dependent on the concentrations of Mn and glial activation. The amount of Mn in glia was not affected by activation or Mn concentration. In vivo, no significant signal enhancement was detected using T1 mapping by glial activation.

Yutong Liu¹, Aditya N. Bade², Larisa Y Poluektova², Santhi Gorantla², Howard E. Gendelman², and Michael D. Boska^1
1Department of Radiology, University of Nebraska Medical Center, Omaha, NE, United States, ²Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, United States

MEMRI was performed on a mouse model of HIV-1 encephalitis generated by intracranial injection of HIV-1 infected monocyte-derived macrophages into caudate and putamen. Histological analysis showed HIV-1 infected human monocytes and gliosis about the injection sites. MEMRI showed signal enhancement in the same regions. Based on a study of neuronal and glial Mn uptake during neuroinflammation, we hypothesize that the signal enhancement results from the increased neuronal activity as a result of gliosis stimulating Mn uptake.

Hadley Bergstrom¹, Haiying Tang^2,3, Jennifer McGuire³, Asamoah Bosomtwi³, Luke Johnson^1,3, Afonso Silva⁴, and Reed Selwyn^2,3
1Psychiatry, Uniformed Services University, Bethesda, MD, United States, ²Radiology, Uniformed Services University, Bethesda, MD, United States, ³Center for Neuroscience and Regenerative Medicine, Uniformed Services University, Bethesda, MD, United States, ⁴National Institute of Neurological Disorders and Stroke, National Insitutes of Health, Bethesda, MD, United States

 

YauYau Wai^1,2, Jyuhn-Huarng Juang³, Chia-Rui Shen⁴, Zei-Tsan Tsai³, Jiun-Jie Wang^4,5, and YiMing Wu^3
1Medical Imaging and Radiological Sciences, ChangGung University, TaoYuan, Taiwan, Taiwan, ²Chang Gung Memorial Hospital, TaoYuan, Taiwan, Taiwan, ³Chang Gung Memorial Hospital, ⁴ChangGung University, ⁵molecular imaging center, Chang Gung Memorial Hospital

Imaging of beta-cells provides a valuable tool for follow-up the progression of diabetes. Manganese (Mn(2+)) is a T1 contrast agent that can enter the pancreatic beta-cells through voltage-gated calcium channels. In this study, Mn(2+)- enhanced MRI after glucose infusion was acquired to detect the beta-cells in vivo. Both normal and diabetic mice were fasted and imaged. 20 minutes prior to MR acquisition, glucose was injected followed by MnCl2 administration. Pancreas was enhanced in the healthy mouse but the enhancement was reduced in the diabetic animal. Mn(2+)-enhanced MRI may allow for in vivo detection of beta-cells .

Kevin C. Chan^1,2, Jiang Li^3,4, Iris Y. Zhou^1,5, Phillis Kau^3,4, Kwok-fai So^3,4, and Ed X. Wu^1,5
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong, China, ²Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States, ³Department of Anatomy, The University of Hong Kong, Pokfulam, Hong Kong, China, ⁴State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Pokfulam, Hong Kong, China, ⁵Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China

This study explores the capability of high-resolution Mn-enhanced MRI (MEMRI) for in vivo, longitudinal evaluation of primary and secondary degeneration along the retinocollicular projections after partial transection of right superior optic nerve in rats. At 1 week and 6 weeks after partial optic nerve injury, a consistent T1W hypointensity by about 28% was observed in the left lateral superior colliculus (SC) relative to the contralateral hemisphere, reflective of primary loss of topological connections and Mn2+ transport in the retinocollicular projections. The left medial SC had a reduced T1W signal intensity by 11% compared to the right medial SC at Week 1. Such reduction further increased to 16% at Week 6, indicative of secondary loss of retinal ganglion cells and axons projecting through the uninjured, inferior optic nerve. The results of this study demonstrated the feasibility of in vivo, high-resolution MEMRI for assessing the primary and secondary degeneration topologically and longitudinally along the visual pathway. Future MEMRI studies are envisioned that measure the secondary changes in topological connections in various neurodegenerative diseases and injuries and upon therapeutic interventions in longitudinal studies.

Tiffany Thiel¹, Endre Agoston¹, Keelan Tuel¹, Ravi Rajpoot¹, Hsiao-Fang Liang¹, and Shu-Wei Sun^1,2
1Loma Linda University, Loma Linda, CA, United States, ²University of California, Riverside, CA, United States

Topical loaded MEMRI with 1M MnCl2 was performed biweekly for 14 weeks. Toward the end of time course, some mice appeared white eye. To evaluate the corneal and retinal integrity of these mice, Optical Coherence Imaging (OCT) and Diffusion Tensor Imaging (DTI) were used to examine animals at the end of the time course. OCT confirmed the corneal damage in the white-eye mice. Interestingly, MEMRI appeared normal in these corneal injured mice.

Miriam Scadeng¹, Seanna Grob², Karen Duong-Polk², Robert Weinreb², and James Lindsey^2
1Radiology, University Of California San Diego, La Jolla, CA, United States, ²Opthalmology, University Of California San Diego, La Jolla, CA, United States

Injection of MnCl into the eye can increase contrast in visual system neuronal pathways when imaged by MRI. As an in-vivo technique, MEMRI has the potential to be used for repeated studies. However, Mn2+ is known to be neurotoxic, and limited published data exists on how toxic MnCl is to different ocular structures when injected into the eye. This is of particular importance for experiments that use this approach to longitudinally follow degenerative changes in models of neuronal disease. This study determines the effect of a range of MR visible MnCl doses upon the integrity of various ocular structures.

F.Y. Lee^1,2, S.J. Fan^1,2, and E.X. Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong, China, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong, China

The olfactory system plays an important role for survival in rodents and shows robust plasticity after injury. Biological studies have observed regeneration of olfactory axons and synapse formation in the frontal cortex after neonatal unilateral olfactory bulb ablation (OBA). In this study, we aim to investigate how the transneuronal transportation of manganese after OBA would change with time. The results demonstrated that the enhancement in the ipsilateral pPir after OBA decreased at P28 as compared with that at P12, indicating recovery of olfactory function till this time was not very likely, although olfactory neurons would reconstituted within 30 days and form glomeruli-like structures.

Geoffrey Topping¹, Andrew Yung², Paul Schaffer³, Piotr Kozlowski², Thomas Ruth³, and Vesna Sossi^1
1Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada, ²MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada, ³Nuclear Medicine, TRIUMF, Vancouver, British Columbia, Canada

Manganese concentration was measured in the rat brain using MRI T1 mapping and positron emission tomography with the radiotracer Mn-52 after IP and IV injections. Within the brain, results are similar between modalities, with short-term Mn accumulation seen prominently in the pituitary. This similarity suggests pharmacological effects do not significantly affect short term Mn uptake.

Øystein Olsen¹, Kristine Skårdal², Else-Marie Huuse², Yrr Mørch³, Marte Thuen², and Marius Widerøe^2
1Department of Radiography, Sør-Trøndelag University College, Trondheim, Norway, ²Department of Circulation and Medical Imaging, University of Science and Technology, Trondheim, Norway, ³SINTEF, Trondheim, Norway

In this study temporal relaxation curves were extracted from T₁ maps of rat brain tissue 6h, 24h, 3d, 6d and 10d after intraperitoneal injection of 1); manganese alginate beads (MnAlg) 40mg/kg, 2); MnAlg 120mg/kg and MnCl₂ 40mg/kg. Manganese releasing alginate beads provided good manganese-enhancement with reduction in T₁comparable to that of MnCl₂ in the rat brain.

Mohammed Salman Shazeeb¹, and Christopher Sotak^2
1Radiology, University of Massachusetts Medical School, Worcester, MA, United States, ²Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA, United States

Manganese (Mn²⁺) is a T₁ contrast agent used in MEMRI studies to visualize functional neural tracts and anatomy in the brain. In animal studies, high doses of Mn²⁺ are desired to maximize contrast. Unlike the intravenous Mn²⁺ injection, which results in fast initial bioelimination of Mn²⁺ from plasma, the subcutaneous (SC) injection can deliver a much higher dose of Mn²⁺ since it releases the Mn²⁺ slowly into the bloodstream while avoiding immediate hepatic elimination and minimizing toxic effects. SC Mn²⁺ injection led to a dose-dependent response of T₁ relaxation times and a prolonged accumulation of Mn²⁺ in the rat brain.

Nataliya Moldovan¹, and Nicholas A. Bock^1
1McMaster University, Hamilton, ON, Canada

MEMRI is widely used in animal brain imaging with divalent manganese providing T1 contrast. However, given that manganese shares transporter proteins with iron and copper, the contrast may be a result of disrupted transition metal homeostasis in the brain. We measured the regional manganese, iron, and copper levels in rodent brains treated with fractionated high-doses of manganese using x-ray fluorescence and neutron activation analysis. We found that overall metal homeostasis was not disrupted, except for decreasing iron levels in the thalamus. This decrease in iron could result in a significant change in MEMRI contrast.

Loredana Sorina Truica¹, Keiko McCreary¹, and Albert Cross^1
1Neuroscience, Canadian Centre for Behaviour in Neuroscience, Lethbridge, Alberta, Canada

Manganese enhanced magnetic resonance imaging (MEMRI) is becoming widely used as a neuro-anatomical and functional tool in studies of animal models. To quantify the Mn distribution and improve the sensitivity, T1 mapping is normally used. It is known that the paramagnetic relaxation properties of manganese in solution are unique with an unusually large ratio of T1 to T2. This study investigates the addition of T2 mapping to the detection of low-level changes of manganese and demonstrates how T1/T2 ratio mapping may be used to reveal contrast specific to manganese.

Hsiao-Fang Liang¹, Tiffany Thiel¹, Erik Valenti¹, Martha Henao¹, and Shu-Wei Sun^1,2
1Loma Linda University, Loma Linda, CA, United States, ²University of California, Riverside, CA, United States

Topical loaded MEMRI was performed biweekly for 14 weeks. The 1M MnCl2 solution was prepared in 4 variations: 1M MnCl2 in PBS saline (Group 1) or DI water (Group 2) a day before the topical administration, NaOH to adjust pH in 1 day old 1M MnCl2 in DI water (group 3), and fresh-prepared 1M MnCl2 in DI water (group 4). Consistent and reproducible MEMRI were seen in all groups except Group 2. One mouse in Group 2 showed significant optic nerve damage.

J. Keiko McCreary¹, Albert R. Cross¹, Gerlinde A.S. Metz¹, and L. Sorina Truica^1
1Neuroscience, Canadian Center for Behavioural Neuroscience, Lethbridge, Alberta, Canada

In this study we investigated the use of an intra-cerebro-ventricular cannulation with the use of an osmotic pump to administer a continuous dose of MnCl2 and its effect on the tissue and behaviour. Here we compare a 7-day administration of Mn to a 28-day administration. In our study, we investigated histology, T1 mapping and behaviour.

Dana S Poole¹, Nathalie Doorenweerd¹, Ahmed Mahfouz^1,2, Marcel J.T. Reinders², and Louise van der Weerd^1,3
1Radiology, Leiden University Medical Centre, Leiden, Zuid Holland, Netherlands, ²Computer Vision Lab, Delft University of Technology, Delft, Netherlands, ³Anatomy and Embriology, Leiden University Medical Centre

Few studies until now have used manganese-enhance MRI (MEMRI) for general phenotyping of transgenic animals. A high dose of manganese ensures a high quality and contrast of the acquired images while reducing the acquisition time, which is beneficial for phenotyping studies containing large numbers of animals. In the present study, we deliver successfully to C57Bl6J mice the highest dose attempted so far: 480mg/kg MnCl2, achieving a high contrast while circumventing weight loss or visible signs of distress. This manganese administration protocol will be of particular use to study brain activation patterns occurring over several days, such as in transgenic or chronic disease models.

Benjamin Winthrop Little^1,2, Umer Khan², Hameetha Rajamohamedsait¹, Lindsay K Hill², Leslie Pendery², Dung Minh Hoang², Einar M Sigurdsson^1,3, and Youssef Z Wadghiri^2
1Physiology & Neuroscience, New York University School of Medicine, New York, New York, United States, ²Radiology, New York University School of Medicine, New York, New York, United States, ³Psychiatry, New York University School of Medicine, New York, New York, United States

 

Taeko Inoue¹, Tabassum Majid^1,2, and Robia Pautler^1,2
1Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, United States, ²Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX, United States

MEMRI is an extremely useful imaging tool to demonstrate deficits in neuronal connectivity or axonal transport. We have previously used MEMRI to demonstrate axonal transport deficits in the Tg2576 mouse model of Alzheimer’s disease as well as improvements in Tg2576 mice that overexpress the antioxidant protein, SOD-2. To elucidate the mechanisms of these axonal transport deficits and improvements, we have combined our MEMRI data with a proteomic analysis. These data together are allowing us to understand the molecular mechanisms of the MEMRI transport deficits and improvements we have observed. Such data will allow for the development of targeted therapeutic strategies.

Nai-Ying Kuo^1,2, Yeu-Sheng Tyan^1,3, and Jun-Cheng Weng^1,3
1School of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan, ²Department of Electrical Engineering, National Tsing Hua University, Hsinchu, Taiwan, ³Department of Medical Imaging, Chung Shan Medical University Hospital, Taichung, Taiwan

Radiological and nuclear medicine examinations as well as radiotherapy during pregnancy have been associated with a slightly increased risk of brain tumor. Radiation exposure during the embryonic period causes various diseases such as hydrocephalus, microcephaly, hippocampal atrophy and other brain disorder. The radiation exposure induced hydrocephalus is responsible for dilatation of the cerebral ventricles and disruption of vascular endothelial cells. Recently it has been demonstrated that manganese-enhanced magnetic resonance imaging (MEMRI) can be used to visualize neuroarchitecture. MEMRI may also be useful in the evaluation of radiation-induced central nervous system (CNS) disorder. Therefore the goal of our study is to assess developmental CNS disorder induced by prenatal radiation exposure with MEMRI. Our results showed that changes in longitudinal relaxation time (T1) induced by intracellular Mn2+ contrast agents and changes in volume were quantitatively observed in the hippocampal area, ventricles and entire brain of normal and radiation-exposed rats.

Haichen Niu¹, Dai Shan¹, Shaorui Li¹, Xuxia Wang¹, Fuchun Lin¹, and Hao Lei^1
1State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China

Chronic morphine exposure induces dependence. Abstinence from the drug causes withdrawal symptoms. Many previous studies have investigated the neural substrate of morphine withdrawal symptoms. In this study, we employed manganese-enhanced MRI (MEMRI) technique to map accumlative brain activities in morphine-treated rat in a 24-hour period during spontaneous withdrawal.

M. Ayaz Khan^1,2, Naveed Bawany³, Rosemary Parker², Cynthia Tinajero², Jaladhar Neelavalli⁴, E. Mark Haacke^3,4, and Rong Zhang^1,2
1Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, United States, ²Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, Texas, United States, ³Biomedical Engineering Department, Wayne State University, Detroit, MI, United States, ⁴Radiology, Wayne State University, Detroit, MI, United States

Iron accumulation is basal ganglia is associated with aging. In this study susceptibility maps were generated to quantify iron in brain structure in wide range (21-69) of subjects.

Wei Li¹, Christian Langkammer², Reinhold Schmidt², Stefan Ropele², and Chunlei Liu^1,3
1Brain Imaging & Analysis Center, Duke University, Durham, North Carolina, United States, ²Neurology, Medical University of Graz, Graz, Austria, ³Radiology, Duke University, Durham, North Carolina, United States

Magnetic susceptibility shows good gray and white matter contrast, and may provide valuable information regarding iron deposits and myelination in brain tissue. In this study, we correlated susceptibility contrast in sensory and motor cortex with clinical cognitive scores in 115 healthy volunteers ranging from 40-83 y/o. It is found that decreased susceptibility contrast in sensory cortex was associated with reduced cognitive performance as demonstrated by the increased errors in Wisconsin card sorting test. These results may suggest the potential value of magnetic susceptibility contrast for assessment of the healthiness of cerebral cortex in the human brain.

Jason Langley¹, Longchuan Li¹, Xiaodong Zhang², and Xiaoping Hu^1
1Department of Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, Georgia, United States, ²Division of Neuroscience, Yerkes National Primate Research Center, Atlanta, Georgia, United States

In this abstract we give estimates of iron content in the putamen, cuneus, caudate nucleus, and globus palladius of a macaque brain.

Venkata Veerendranadh Chebrolu¹, Subhamoy Mandal¹, Sheshadri Thiruvenkadam¹, Rakesh Mullick¹, and John F Schenck^2
1GE Global Research, Bangalore, Karnataka, India, ²GE Global Research, Niskayuna, NY, United States

Accurate quantification of brain iron would be useful in early diagnosis of Alzheimer’s disease. In this work the MR acquisition parameters for quantitative measurement of brain iron (T2) were optimized through the use of Cramér-Rao bound (CRB) analysis. The noise performance at different echo-times was analyzed at different signal-to-noise ratios and at different T2. CRB analysis shows that noise performance is independent of first echo-time and there exists a line of optimality around which the optimal second echo-times for a two echo acquisition are clustered.

Olivier Baledent¹, Bader Chaarani¹, Olivier Pottie¹, Catherine Gondry-Jouet², Jadwiga Zmudka³, Jean-Marie Serot³, and Roger Bouzerar^1
1Image Processing Unit, University Hospital, Amiens, France, ²Radiology, University Hospital, Amiens, France, ³Geriatric Unit, University Hospital, Amiens, France

The cerebrospinal fluid is produced in the highly vascularized choroid plexus (CP). Our goal is to evaluate dynamic T2*-weighted perfusion MR imaging for assessment of CP functionality. Gradient-echo EPI sequences were performed in 15 patients after bolus injection of gadolinium-based contrast agent. The MR signal modeled in terms of the combined T1- and T2-effects allowed the extraction of a capillary permeability parameter K2. Mean volume of CP was 2124 mm3 and mean permeability factor was 0.033 s-1. K2 significantly decreased with subject's age whereas mean transit time significantly increased. Clinical applications such as neurodegenerative diseases could be considered.

F Kara¹, E S van Dongen¹, R Schliebs², M A van Buchem³, H J.M. de Groot¹, and A Alia^1,3
1Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands, ²Department of Neurochemistry, University of Leipzig, Leipzig, Germany, ³Department of Radiology, Leiden University Medical Center, Leiden, Netherlands

In this work we present the first ultra-high field (17.6 T) MR Angiography study to monitor age-dependent cerebrovascular alterations in the Tg2576 mouse model of AD. The blood flow alterations observed in middle cerebral artery and anterior communicating artery increased in transgenic mice compared to wild-type mice over time. Histological data revealed that these alterations such as signal voids might be correlated with severity of Aâ type of cerebral amyloid angiopathy. Our results show that ultra-high field MRA is a powerful tool to monitor blood flow alterations longitudinally in living mice.

Yu Zhang^1,2, Norbert Schuff^1,2, Kristine Yaffe², Howard Rosen², Bruce Miller², and Michael Weiner^1,2
1Center for Imaging of Neurodegenerative Diseases, VA Medical Center, San Francisco, San Francisco, CA, United States, ²University of California, San Francisco, San Francisco, CA, United States

Previous studies have used univariate tests of diffusion tensor metrics such as fractional anisotropy (FA) or radial diffusivity (DR) to classify mild cognitive impairment (MCI) subjects and healthy elderly controls. This study applied multivariate tests of DTI, including simultaneously all three diffusion tensor eigenvalues in a large sample of 54 MCI and 66 control subjects. The results show that multivariate tests of the diffusion eigenvalues detect regions of white matter alterations more consistently than univariate-tests. This method has potential to identify early cognitive impairment.

Wenshu Qian¹, Zhongping Zhang¹, Ed X. Wu², Pek-Lan Khong¹, and Mina Kim^1
1Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong, Hong Kong, China, ²Departments of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China

Diffusion kurtosis imaging (DKI), as an extension of conventional diffusion tensor imaging (DTI), was recently proposed to probe a non-Gaussian diffusion property. In this study, we aimed to characterize microstructural changes in a deep grey matter region using DKI at 3 Tesla clinical MRI system. Our results demonstrate that age-related changes in brain can be quantitatively assessed using DKI.

Xiaozhen Li¹, Tie-Qiang Li², Raffaella Crinelli¹, Hakan Fisher³, Anna Rieckmann⁴, and Lars-Olof Wahlund^1
1Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Stockholm, Sweden, ²Department of Medical Physics, Karolinska Institutet, Stockholm, Stockholm, Sweden, ³Department of Psychology, Stockholm University, Stockholm, Stockholm, Sweden, ⁴Aging Research Center, Karolinska Institutet, Stockholm, Stockholm, Sweden

In this study, we evaluated the abnormal changes of both microstructure and functional connectivity in Default Mode Network (DMN) in Alzheimer's Disease (AD) and Mild Cognitive Impairment (MCI) subjects using Diffusion Tensor Imaging (DTI) and resting-state function MRI (rs-fMRI).We found MCI shares features with AD. The structural and functional connectivity of DMN in both AD and MCI patients are abnormal.Our investigation is beneficial to further understanding of the structural and functional changes of AD in different stages.Moreover, it may contribute to an improved differential diagnosis in AD and MCI which are often clinically difficult to distinguish.

Peter J Nestor¹, Stephanie Alley², Guy B Williams³, Dina Kronhaus², and Julio Acosta-Cabronero^1
1Department of Clinical Neurosciences, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom, ²Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom, ³Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom

Various, sometimes inconsistent, results have been reported in Alzheimer’s disease (AD) using DTI. This study explored the hypothesis that this may, in part, relate to different tensor behaviors at different disease stages. Region of interest and whole brain approaches were used to study changes in DTI metrics in (i) two AD cohorts of differing severity and (ii) a cohort that had been scanned longitudinally. The results indicated that axial diffusion became abnormal early but then remained relatively static with advancing disease. Radial diffusion, and therefore fractional anisotropy, were relatively preserved early but became increasingly abnormal with disease progression.

Rachelle Crescenzi^1,2, Daniel Adler³, Paul A. Yushkevich³, Virginia M.-Y. Lee⁴, John A. Detre⁵, and Arijitt Borthakur^2
1Department of Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, United States, ²CMROI Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, ³PICSL Department of Radiology, University of Pennsylvania, ⁴CNDR Department of Pathology & Lab Medicine, University of Pennsylvania, ⁵CfN Department of Neurology, University of Pennsylvania

Alzheimer’s disease has two characteristic pathologies, amyloid-beta plaques and hyperphosphorylated tau protein that forms neurofibrillary tangles. We seek to study whether the PS19 mouse model of tau pathology follows the same trend in diffusion measures as Alzheimer’s disease patients and the amyloid-beta mouse model. Mean diffusivity (MD) and fractional anisotropy is measured in excised brains of PS19 mice and age-matched controls. In the young cohort of mice, significant differences in diffusion measures were seen in the hippocampus and cortex. While MD is reduced in younger PS19 mice, MD increases in older PS19 mice and decreases in the WT cohort.

Cheryl R McCreary^1,2, Emily Donaldson³, Karla G Sanchez³, Eric E Smith^3,4, and Richard Frayne^1,2
1Radiology, University of Calgary, Calgary, Alberta, Canada, ²Seaman Family MR Research Centre, Foothills Medical Centre, Calgary, Alberta, Canada, ³Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada, ⁴Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada

Age-related white matter hyperintensities (WMH) reflect various underlying tissue pathologies, including ischemic demyelination, microinfarction and axonal loss, and may identify tissue abnormalities of varying severity. Diffusion tensor imaging parameters such as fractional anisotropy (FA) and mean diffusivity (MD) are proposed to be more sensitive to the underlying white matter structural integrity and more closely associated with cognitive function. Using histogram analysis of a) WMH, b) normal appearing brain parenchyma, and c) whole brain in subjects with cerebral amyloid angiopathy (CAA) and healthy age-matched subjects, we found MD peak and MD peak height, were correlated with verbal memory, executive function, visual memory and visual perception and processing speed (VPPS). WMH volume was less strongly correlated with verbal memory and VPPS and was not significantly associated with executive function or verbal memory.

Yumei Yan¹, Longchuan Li², Todd Preuss³, Xiaoping Hu², James G Herndon³, and Xiaodong Zhang^1,3
1Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States, ²Department of Biomedical Engineering, Emory University and Georgia institute of Technology, Atlanta, GA, United States, ³Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, GA, United States

Age-related optic nerve degeneration was observed in previous ex-vivo studies of human or animal specimens. In this study, optic nerve diffusivity in aged female rhesus monkeys was investigated systematically with DTI. Mean diffusivity, axial and radial diffusivity were observed increasing during aging, which is consistent with the DTI findings on brain white matter in aged human. No significant changes of FA and fiber tract number were observed, which is in agreement with the ex-vivo result of optic nerve aging in rhesus monkeys. These results suggest that the diffusivity parameters may be potential markers to evaluate optic nerve disorders during aging.

Peter Mannfolk¹, Markus Nilsson², Sebastian Palmqvist³, Lennart Minthon³, Pia Maly Sundgren¹, and Oskar Hansson^3
1Center for Medical Imaging and Physiology, Skåne University Hospital, Lund, Sweden, ²Dept. of Medical Radiation Physics, Lund University, Lund, Sweden, ³Clinical Memory Research Unit, Dept. of Clinical Sciences, Lund University, Malmö, Sweden

Treatment of Alzheimer’s disease (AD) depends upon markers to identify disease at a very early stage. Associations between cerebrospinal fluid (CSF) biomarkers and incipient AD have been established, and in this work, we investigated functional connectivity within the default mode network (DMN) in patients diagnosed with mild cognitive impairment (MCI). The patients were characterized in terms of exhibiting non-pathological or pathological CSF biomarkers, and resting state fMRI data was investigated with respect to corresponding differences in connectivity. The findings of the study indicate that connectivity of hippocampus with other nodes of the DMN is altered between the two sub groups.

Oranan Tritanon¹, Jiraporn Laothamatas¹, Chewarat Wirojtananugoon¹, Witaya Sungkarat¹, Chakrit Sukying², and Sirintorn Chansirikarnjana^3
1Advanced Diagnostic Imaging and Image-Guided Minimal Invasive Therapy Center and Radiology Dept., Ramathibodi Hospital Faculty of Medicine, Mahidol University, Rajataewe, Bangkok, Thailand, ²Department of Psychiatry, Ramathibodi Hospital Faculty of Medicine, Mahidol University, Rajataewe, Bangkok, Thailand, ³Department of Medicine, Ramathibodi Hospital Faculty of Medicine, Mahidol University, Rajataewe, Bangkok, Thailand

Voxel-wise group analyses of DTI in AD, MCI, and age-matched control group based on a new whole-brain probabilistic tractography normalization process revealed very statistical significant changes among the groups.

zhiqun wang¹, and kuncheng li^1
1Radiology, XuanWu Hospital, Beijing, Beijing, China

Background: Recently, resting-state functional MRI (fMRI) has attracted increasing attention. Most studies have focused on the posterior cingulate cortex (PCC) connectivity£¬while less attention has been devoted to the longitudinal changes of PCC connectivity. Methods: Resting state fMRI was used to examine baseline and longitudinal changes in PCC connectivity in mild cognitive impairment (MCI), which presented a neuro-disconnection syndrome. Results: Functional connectivity between the PCC and a set of regions was decreased in MCI. After 3 years, we found increased and decreased functional connectivity between the PCC and some regions in MCI. Conclusions: This study offered a clue to the reduced integrity and compensation in PCC-related network in MCI.

Y.C. Shih^1,2, Kayako Matsuo², S.H. A. Chen³, Toshiharu Nakai⁴, Y.C. Hsu⁵, F.H. Lin¹, and W.Y. I. Tseng^2
1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, Taiwan, ²Center for Optoelectronic Biomedicine, National Taiwan Univerity College of Medicine, Taipei, Taiwan, Taiwan, ³Division of Psychology, Nanyang Technological University, Singapore, Singapore, Singapore, ⁴National Center for Geriatrics and Gerontology, Aichi, Japan, ⁵Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University

We performed resting state fMRI to investigate the functional connectivity of elderly people placing seed regions in the anterior and the posterior hippocampus using a . A regression model. The anterior hippocampus seed revealed a memory network including an anterior part of the temporal lobe and the insula. In contrast, the posterior seed revealed a network including the posterior cingulate cortex (PCC). The was used to efficiently detect the functionally coherent cerebral regions with these hippocampus seeds. We hypothesized that elderly people show the different signal coherence pattern in the hippocampal memory network. Eelderly group demonstrated higher signal coherence in the left right PCC, right insula and superior right anterior temporal lobe with the posterior hippocampus and anterior hippocampus than the young group. It would be explained eElderly people may have a compensatory mechanism to ensure higher cognitive memory functions caused byaffected by aging and experiences.

Julio Acosta-Cabronero¹, Stephanie Alley², Guy B Williams³, and Peter J Nestor^1
1Department of Clinical Neurosciences, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom, ²Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom, ³Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom

In early-stage clinical Alzheimer’s disease, the most prominent alterations measured by diffusion tensor imaging are characterised by the apparent increase in both axial and transverse self-diffusion components. This tensor behaviour, however, causes fractional anisotropy to grossly underestimate the true extent of early abnormalities. In this study, we explored a wide range of anisotropy metrics, and found that white matter changes in mild Alzheimer’s disease are best described by the loss of tensor planarity.

Toshiaki Taoka¹, Masahiko Sakamoto¹, Toshiaki Akashi¹, Masaaki Hori², Shigeki Aoki², Yoshitaka Masutani³, Masayuki Morikawa⁴, Kuniaki Kiuchi⁴, Toshifumi Kishimoto⁴, and Kimihiko Kichikawa^1
1Radiology, Nara Medical University, Kashihara, Nara, Japan, ²Radiology, Juntendo University, Tokyo, Japan, ³Radiology, Tokyo University, Tokyo, Japan, ⁴Psychiatry, Nara Medical University, Kashihara, Nara, Japan

Q-space imaging (QSI) can identify the molecular diffusion probability density function without assuming a Gaussian distribution, and can provide quantitative information on tissue architecture. We made tract based analysis of QSI for the limbic system including uncinate and posterior cingulum in the clinical cases with Alzheimer diseases (AD). As our result, we observed decreased provability for 0 displacement, broader full width at half maximum and sharper mean apparent kurtosis coefficients in AD cases. These changes in QSI parameters seem to be due to the changes in histological structures along the tracts within limbic system in the cases with AD.

Jeremy Goh^1,2, Tracy Melzer^2,3, Richard Watts⁴, Michael McAskill^2,3, Toni Pitcher^2,3, Leslie Livingston^2,3, Ross Keenan⁵, Tim Anderson^2,6, and John Dalrymple-Alford^1,2
1Department of Psychology, University of Canterbury, Christchurch, Canterbury, New Zealand, ²New Zealand Brain Research Institute, Christchurch, Canterbury, New Zealand, ³Department of Medicine, University of Otago, Dunedin, New Zealand, ⁴College of Medicine, University of Vermont, Burlington, Vermont, United States,⁵Christchurch Radiology Group, Christchurch, Canterbury, New Zealand, ⁶Department of Neurology, Christchurch Hospital, Christchurch, Canterbury, New Zealand

The Default Mode Network (DMN) is evaluated in three groups of patients with Parkinson's Disease (PD) and one group of healthy controls (HC). The three groups are patients with PD without a diagnosis of neurological disorders (PD-N), patients with mild cognitive impairment (PD-MCI), and patients with a diagnosis of dementia (PD-D). The MD values across the DMN differed significantly across the four groups (F(3,122) = 6.26, p<0.001), with significant post-hoc Newman-Keuls differences between the PD-D group and all other groups, and significant differences between the PD-MCI group and both PD-N and the HC groups, which did not differ.

Babak A Ardekani^1,2, and Laszlo Zaborszky^3
1Center for Advanced Brain Imaging, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States, ²Department of Psychiatry, New York University School of Medicine, New York, New York, United States, ³Center for Molecular and Behavioral Neuroscience, Rutgers University, Newark, New Jersey, United States

We propose the rate of change with time of the centroid size (S) of the mid-sagittal cross-sectional area of the corpus callosum as new biomarker that separates Alzheimer’s Disease (AD) from normal aging based on longitudinal structural MRI scans. Using data from the AD Neuroimaging Initiative (ADNI), we show that S increases with time in both normal aging and AD. However, the change in S is significantly greater in AD as compared to normal control subjects. Therefore, we suggest that change in S can be used as a reliable biomarker to predict conversion from mild cognitive impairment to AD.

Dominic Holland¹, Linda K McEvoy², Rahul S Desikan², and Anders M Dale^1,2
1Neurosciences, UCSD, La Jolla, CA, United States, ²Radiology, UCSD

Longitudinal structural MRI enables sensitive quantification of change taking place in brain regions. When applied to Alzheimer disease, rates of structural change in specific brain regions offer potential outcome measures for clinical trials that are significantly more powerful than clinical measures, and can be combined with other baseline biomarkers for further significant enhancement of power. Rates of change can be measured with enough fidelity that annual rates of change as a function of baseline age can be calculated, revealing attenuation with increasing age in the relationship between rates of decline and disease severity, and enabling disease trajectories to be modeled.

Song Lai¹, and John Lackey^1
1Radiology, Thomas Jefferson University, Philadelphia, PA, United States

 

Nicolas Cherbuin¹, Perminder S. Sachdev², and Kaarin J. Anstey^1
1Australian National University, Canberra, ACT, Australia, ²University of New South Wales, Sydney, NSW, Australia

Clear associations have been demonstrated between type two diabetes (T2D), the metabolic syndrome, obesity and brain atrophy and cognitive decline. However, little is known about the effect higher blood glucose levels within the normal range have on brain health in cognitively healthy individuals without T2D. Relationships between fasting glucose levels and atrophy of a cerebral structure particularly sensitive to pathophysiological stressors, the hippocampus, were tested using data from a large longitudinal study of mental health and ageing. This study reports negative associations between hippocampal atrophy over 4 years and fasting plasma glucose levels in 266 older community-based individuals.

David Raffelt^1,2, J-Donald Tournier^1,3, Stuart Crozier⁴, Kathryn A Ellis⁵, Ralph Martins⁶, Victor L Villemagne^3,7, Colin L Masters⁷, David Ames⁸, Christopher C Rowe³, Olivier Salvado², and Alan Connelly^1,3
1Brain Research Institute, Florey Neuroscience Institutes, Melbourne, VIC, Australia, ²The Australian E-Health Research Centre, CSIRO, Brisbane, QLD, Australia, ³Department of Medicine, University of Melbourne, Melbourne, VIC, Australia, ⁴Biomedical Engineering, School of ITEE, University of Queensland, Brisbane, QLD, Australia, ⁵Department of Psychiatry, University of Melbourne, Melbourne, VIC, ⁶Edith Cowan University, Centre of Excellence for Alzheimer’s Disease Research & Care, Joondalup, WA, Australia, ⁷The Mental Health Research Institute, University of Melbourne, Melbourne, VIC, Australia, ⁸Department of Radiology, University of Melbourne, Melbourne, VIC, Australia

In this work, we investigate Alzheimer’s Disease (AD) using a recently developed method for voxel-based analysis (VBA) of diffusion-weighted MRI called Apparent Fibre Density (AFD). Unlike existing measures such as Fractional Anisotropy, AFD permits population differences to be localised in both the spatial and orientation domains. This enables pathology-induced changes to be attributed to a single fibre population in a region containing multiple fibres. Our findings demonstrate a significant decrease in AFD in AD patients compared to healthy subjects within voxels and orientations corresponding to the cingulum, corpus callosum, uncinate fasciculus, and superior longitudinal fasciculus and anterior commissure.

M. Vittoria Spampinato¹, Markus Weininger², Karen Patrick², Ryan Parker², and Hrvoje Vavro^3
1Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, United States, ²Medical University of South Carolina, ³University Hospital Dubrava, Zagreb, Croatia

We assessed gender-specific differences in gray matter (GM) atrophy patterns in patients with conversion from amnestic mild cognitive impairment to Alzheimer's disease (AD). Voxel-based morphometry was used to process longitudinal MR data obtained at 12 months intervals (from 12 months before, to 12 months after the diagnosis of AD). Baseline group comparison showed greater atrophy in the posterior cingulate gyrus in females than males. Longitudinal analyses revealed that the extent and distribution of GM atrophy in early AD is strongly influenced by gender, with faster rate of GM volume loss in men compared to women at the same disease stage.

M. Vittoria Spampinato¹, Ryan Parker², Karen Elizabeth Patrick², Zoran Rumboldt¹, Jacobo Mintzer³, and Hrvoje Vavro^4
1Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC, United States, ²Medical University of South Carolina, Charleston, SC, United States,³Neurosciences, Medical University of South Carolina, Charleston, SC, United States, ⁴Diagnostic and Interventional Radiology, University Hospital Dubrava, Zagreb, Croatia

We used voxel-based morphometry to assess patterns of gray matter (GM) volume loss in subjects with early Alzheimer’s disease with and without naming impairment. Longitudinal MR data obtained at the time of diagnosis and 12 months later was processed. Subjects with naming impairment showed greater GM atrophy in left temporal, frontal and parietal lobe. Subjects without naming impairment had an overall milder GM volume loss, specifically in the bilateral temporal and frontal regions. Bilateral hippocampal GM volume loss was present in both groups. The distribution and extent of GM volume loss differ in presence or absence of word retrieval impairment.

James A Goodman¹, Gary B Freeman², William Angus², Thomas P Brown³, Peter Cheng-te Chou¹, and Kelly R Bales^4
1Pharmatherapeutics Precision Medicine Preclinical Imaging, Pfizer Worldwide Research and Development, Groton, CT, United States, ²General Toxicology, Pfizer Worldwide Research and Development, Groton, CT, United States, ³Investigative Pathology, Pfizer Worldwide Research and Development, Groton, CT, United States, ⁴Neuroscience Research Unit, Pfizer Worldwide Research and Development, Groton, CT, United States

Amyloid Related Imaging Abnormalities of the microhemorrhage (ARIA-H) and effusive/edematous (ARIA-E) types have been reported in clinical trials in AD patients given agents targeting â-amyloid, prompting interest in identifying animal models to elucidate these ARIAs. While ARIA-H has been reported in transgenic mouse models, no publications to our knowledge describe ARIA-E in mice. We imaged 3 lines of aged transgenic mice: APP+PS1, Tg2576, and HCHWA-Dutch. While most APP+PS1 mice had T2* hypointensities representing ARIA-H and T2 hyperintensities representing ARIA-E, Tg2576 and HCHWA-Dutch mice had neither, suggesting that the APP+PS1 line is a viable model for evaluating the pathogenesis of ARIA.

Shashwath A Meda¹, Jared G Cobb², Tracy L Wilson², Erin P Hussey³, Brandon A Ally³, Swati D Rane², Manus J Donahue², and Tricia A Thornton-Wells^1,2
1Department of Molecular Physiology & Biophysics, Center for Human Genetics Research, Vanderbilt University Medical Center, Nashville, TN, United States, ²Department of Radiology & Radiological Sciences, Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, United States, ³Department of Neurology, Memory Disorders Research Lab, Vanderbilt University School of Medicine, Nashville, TN, United States

 

Vivek Tiwari¹, and Anant Bahadur Patel^1
1NMR Microimaging and Spectroscopy, Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India

APP-PS1 mice show occasional deposits of amyloid plaques at the age of 5-6 months without significant memory impairment and neuronal loss, characteristics– typical of AD pathology at early stage of the disease. Present study evaluates glutamatergic and GABAergic neurotransmitter energetics in 6 month old APPswe-PS1dE9 by using ¹H-[¹³C]-NMR spectroscopy together with infusion of [1,6-¹³C₂]glucose. Although APPswe-PS1dE9 mice at 6 month age exhibited no significant derangement in neurochemical profile but glucose oxidation and neurotransmitter flux associated with glutamatergic and GABAergic neurons were found to be significantly impaired.

A. Alia^1,2, and F. Kara^1
1Leiden Institute of Chemistry, Leiden University, Leiden, Netherlands, ²Department of Radiology, Leiden University Medical Center, Leiden, Netherlands

In this work we present the first in vivo assessment of glutamate levels in different regions of the brain in 11-month-old Tg2576 mouse at 9.4 T. This metabolite is less studied in Alzheimer’s disease (AD) since detection of this metabolite is challenging in clinical field strengths. In this study, highly significant decrease in glutamate/total creatine has been observed in the cortex region of the transgenic mice compared to wild type mice. The early decrease in glutamate level in the cortex regions of the transgenic mouse can be correlated with previously reported cognitive impairment in this mouse model of AD.

Vivek Tiwari¹, Pandichelvam Veeraiah¹, and Anant Bahadur Patel^1
1NMR Microimaging and Spectroscopy, Centre for Cellular and Molecular Biology, Hyderabad, Andhra Pradesh, India

Alzheimer's disease is associated with dysfunction and deficit of neurotransmitters and synapses. Neurochemicals and cerebral metabolism was studied in 12 month old APP-PS1 mouse model of Alzheimer's disease. Level of Glutamate and NAA was found to be lower while inositol was significantly higher in APP-PS1 mouse. Glucose oxidation by glutamatergic and GABAergic neurons, and neurotransmitter cycling was found to be impaired significantly in APP-PS1 mice. In contrast, astroglial metabolism was found to be higher in APP-PS1 mice at cognitive impaired stage.

Maximilian N. Voelker¹, Stephan Roeskam², Alexander M. Koenig¹, Richard Dodel², and Johannes T. Heverhagen^1
1Diagnostic Radiology, Philipps University, Marburg, Hessen, Germany, ²Department of Neurology, Philipps University, Marburg, Germany

Alzheimer disease can be detected by MRI in APP transgenic mice by T2-Mapping without the need for contrast agent or high resolution imaging. In vivo Alzheimer plaques imaging on transgenic mice is challenging because of small plaque’s size (20 - 70µm), long measurement duration and limitation to ultra high fields (>7T). Indirect measurement of plaque load with T2-Mapping allows faster protocols and differentiation between APP- transgenic mice and wild type mice. Strong effects on T2 have been detected due to accumulation of iron in plaques.

Alexandra Petiet^1,2, Luisa Ciobanu², and Marc Dhenain^3
1Brain and Spine Institute, Paris, Ile-de-France, France, ²CEA NeuroSpin, Gif-sur-Yvette, Ile-de-France, France, ³CEA MIRCen, Fontenay-aux-Roses, Ile-de-France, France

Amyloid plaques, extracellular deposits of b-amyloid peptides, are early markers of Alzheimer’s disease. The majority of them in the cortex and hippocampus are poorly loaded with iron, which requires high sensitivity to detect their presence. We used a 17.2-Tesla magnet to achieve an isotropic resolution of 30 um in 7 hours in a mouse model. The image quality achieved revealed many amyloid plaques throughout the brain. Using very high field magnets allows very high resolution imaging in short times and the increased magnetic susceptibility required for amyloid plaque imaging will benefit their detection in live mouse models.

Pui Wai Chiu¹, Queenie Chan², and Henry Ka Fung Mak^3
1Diagnostic Radiology, The University of Hong Kong, HK, HK, Hong Kong, ²Philips Healthcare, Hong Kong, ³Diagnostic Radiology, The University of Hong Kong

T1 and T2 relaxation time values vary in different regions and magnetic environments. Though T1 and T2 correction factors are necessary in absolute quantification, previous MRS studies mainly obtained the values from literature since the measurements require much time to be conducted. In this 1H-MRS study of aging, T1 and T2 values were measured within the sampling population in order to achieve higher accuracy at 3-Tesla. This study demonstrated the measurements only take reasonable amount of time with our method employed.

Lin Zhang¹, Yong Zhang², Yun-cheng Wu³, and Gui-xiang Zhang^1
1Radiology, Shanghai Jiaotong University Affiliated First People's Hospital, Shanghai, Shanghai, China, ²MR Applied Science Lab, GE Healthcare, Shanghai, China, ³Neurology, Shanghai Jiaotong University Affiliated First People's Hospital, Shanghai, China

This preliminary study investigated the potential to use regional homogeneity (ReHo), a novel resting-state fMRI parameter to characterize the progression of Alzheimer¡¯s Disease (AD). Six AD patients and nine age- and gender-matched healthy controls were recruited for comparison. For the regions of significant difference detected, average ReHo were calculated and correlated with AD patients¡¯ MMSE scores. Compared with normal controls, AD patients showed decreased ReHo in right posterior cingulate/precuneus cortex and left inferior parietal lobe, which were positively correlated to the corresponding MMSE scores. ReHo shows the promise to reflect the cognitive decline in AD patients.

Giovanni Giulietti¹, Marco Bozzali¹, Laura Serra¹, Barbara Spano'¹, Barbara Basile¹, Roberta Perri², Camillo Marra³, Carlo Caltagirone^2,4, and Mara Cercignani^5
1Neuroimaging Laboratory, Foundation IRCCS Santa Lucia, Rome, Italy, ²Department of Clinical and Behavioural Neurology, Foundation IRCCS Santa Lucia, Rome, Italy,³Institute of Neurology, Università Cattolica, Rome, Italy, ⁴Department of Neuroscience, University of Rome Tor Vergata, Rome, Italy, ⁵Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, Brighton, United Kingdom

This study evaluate the sensitivity of quantitative magnetization transfer (qMT) imaging to the subtle tissue changes expected in subjects with amnestic Mild Cognitive Impairment (aMCI), a condition considered as a prodromal stage of AD. To this purpose, a multimodal image analysis was used to take into account grey matter (GM) atrophy. The results confirm that among qMT parameters, RM_0B is the most sensitive to AD pathology. Additionally, this parameter appears to be already reduced in some GM areas of patients with aMCI. These changes are likely to precede the appearance of macroscopic atrophy.

Napapon Sailasuta¹, Kent Harris¹, and Ralph Noeske^2
1HMRI, Pasadena, CA, United States, ²Research and Collaboration, GE Healthcare, Berlin, Germany

We report GABA concentration is reduced in amnestic mild cognitive impaired subjects and proposed that GABA can be used as marker for AD.

Yuanxin Chen¹, Kem A Rogers², and Brian K Rutt^3
1Imaging Research Laboratories, Robarts Research Institute, University of Western Ontario, London, Ontario, Canada, ²Department of Anatomy and Cell biology, University of Western Ontario, London, Canada, ³Department of Radiology, Stanford University, California, United States

Extracellular amyloid deposits constitute the main targets for new diagnostics and therapeutics of Alzheimer¡¯s disease (AD). In this study, we evaluated an ex vivo MR protocol for visualization of amyloid plaques in cholesterol-fed rabbit model of AD. Brain tissue was soaked in the Magnevist to allow contrast agent penetration in the core of brain tissue before MR imaging. We have demonstrated that infiltration of contrast agent increases the detachability of amyloid plaques in the rabbit AD model. These results point to the possibility of using intrathecal injection of contrast agent for in vivo imaging amyloid plaques using clinical-strength MRI.

Andrew J Patterson¹, Andrew J Degnan¹, Victoria E Young¹, Tjun Y Tang², Andrew B Gill³, Martin J Graves¹, and Jonathan H Gillard^1
1Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, England, United Kingdom, ²Department of Vascular Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, England, United Kingdom, ³Medical Physics, Cambridge University Hospitals NHS Foundation Trust, Cambridge, England, United Kingdom

An ex vivo study of carotid endarterectomy specimens reporting quantitative T₁, T₂ and T₂* relaxation times within plaque tissue at 1.5T using spatially co-matched histology sections to determine tissue constituents. This study found a statistically significant difference in T₂ and T₂* in core plaque tissues.

Eric M Schrauben¹, Ashley Anderson¹, Kevin Johnson¹, Aaron Field², and Oliver Wieben^1,2
1Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, United States, ²Radiology, University of Wisconsin - Madison, Madison, Wisconsin, United States

 

Willem Bouvy^1,2, Jaco J.M. Zwanenburg³, Jeroen Hendrikse³, Fredy Visser⁴, Peter R Luijten³, Jaap Kappelle^1,2, and Geert Jan Biessels^1,2
1Neurology, Utrecht University Medical Centre, Utrecht, Netherlands, ²Rudolph Magnus Institute of Neuroscience, Utrecht, Netherlands, ³Radiology, University Medical Center Utrecht, Utrecht, Netherlands, ⁴Philips Healthcare, Best, Netherlands

We developed a 7 Tesla imaging protocol to study the perivascular spaces (PVS) and their correlation with perforating arteries and veins in the brain. Four young, healthy volunteers were scanned. Perivascular spaces were well visualized in all subjects. In the basal ganglia region PVS were connected to the basal cisterns and could be linked to lenticulostriate arteries. In the lobar region PVS could in general not be linked to perforating arteries, but some PVS could be linked to veins. The ability to map PVS and vessels in detail may help to further understand PVS and their relationship to cardiovascular disease.

Alan J Huang^1,2, Craig Jones^1,3, Richard Leigh⁴, Samson Jarso^1,3, and Peter van Zijl^1,3
1FM Kirby Research Center for Functional Brain Imaging, Johns Hopkins University, Baltimore, MD, United States, ²Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States, ³Russell Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University, Baltimore, MD, United States,⁴Department of Neurology, Johns Hopkins University, Baltimore, MD, United States

We demonstrate the initial application of pH-weighted imaging with pulsed CEST to image the ischemic penumbra of an acute cerebral ischemic stroke patient. The magnetization transfer asymmetry ratio around 3.5 ppm was used to compare regions of interest between the patient and a healthy volunteer. The patient showed a region of reduced CEST contrast, which was attributed to tissue acidosis in the ischemic region. This region was larger than the diffusion impaired region but smaller than the perfusion impaired regions.

Chun-Jung Juan¹, Yi-Jui Liu², Yi-Hsiung Lee³, Teng-Yi Huang⁴, Fu-Nien Wang⁵, and Ming-Long Wu^6
1Department of Radiology, Tri-Service General Hospital, Taipei, Taiwan, ²Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, ³P.H.D program in Electrical and Communication Engineering, Feng Chia University, Taichung, Taiwan, ⁴Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, ⁵Department of Biomedical Engineering and Environmental Sciences College of Nuclear Science, National Tsing Hua University, Hsinchu, Taiwan, ⁶Department of Computer Science and Information Engineering, National Cheng Kung University, Tainan, Taiwan

The blood flow waveforms of one cardiac cycle were recorded using cine PCMRI in different hypercapnia condition (0~7% CO2). Vasomotor reactivity (VMR) is an increased percentage change of cerebral perfusion for hypercapnia to normocapnia. Four types of VMR were defined in this study, VMRsys-flow, VMRmean-flow, VMRdia-flow and VMRstr-volume computed by systolic blood flow, mean blood flow, diastolic blood flow and stroke volume, respectively. Although the physiological interpretation of VMR is different between blood volume and flow, our result demonstrated the VMRstr-volume is closer to VMRmean-flow under different CO2 induced hypercapnia comparing with other two blood flow VMR indexes.

Alexander Korutz¹, Parmede Vakil¹, Renee Qian², Ali Habib², Justin Vranic², Michael C Hurley², Ali Shaibani², Timothy J Carroll², and Sameer A Ansari^2
1Northwestern University, Chicago, IL, United States, ²Northwestern University

 

Robert A Knight¹, James R Ewing¹, Kishor Karki¹, Joseph D Fenstermacher², and Tavarekere N Nagaraja^2
1Neurology - NMR Research, Henry Ford Hospital, Detroit, MI, United States, ²Anesthesiology, Henry Ford Hospital, Detroit, MI, United States

The development of edema following cerebral ischemia and reperfusion is a critical factor in determining stroke severity and predicting outcome. As the ischemic injury evolves, the blood-brain barrier often becomes injured, allowing water and contrast agent to leak out of the damaged vessels. Thus, contrast enhanced MRI may represent a potential method for assessing post-stroke edema formation by tracking the interaction of the extravascular water molecules with the leaking MRCA.

Manus Donahue^1,2, Michael Ayad³, Ryan Moore¹, Matthias van Osch⁴, and Megan Strother^1
1Radiology and Radiological Sciences, Vanderbilt University School of Medicine, Nashville, TN, United States, ²Psychiatry, Vanderbilt University School of Medicine, Nashville, TN, United States, ³Neurosurgery, Cornell Medical Center, New York, NY, United States, ⁴Radiology, Leiden University, Leiden, Netherlands

The overall aim of this work is to develop and clinically implement a multi-modal 3.0T MRI protocol capable of quantitatively evaluating the relationship between tissue-level hemodynamic compensation mechanisms and stroke risk in patients with intracranial (IC) steno-occlusive disease. Conclusions demonstrate an inverse relationship (n=15) between baseline cerebral blood flow and angiographic opacification time (P=0.01), a positive correlation between hypercapnic-BOLD time-to-peak and opacification time (P=0.04), and a positive correlation between Modified Suzuki Score and BOLD hypercapnic-reactivity. These findings provide evidence that noninvasive MRI approaches provide complementary, yet noninvasive, information to angiography and clinical scores in IC stenosis patients.

Islem Rekik^1,2, Stéphanie Allassonnière², Stanley Durrleman³, Trevor Carpenter¹, and Joanna Wardlaw^1
1Clinical Neurosciences, Edinburgh University, Edinburgh, United Kingdom, ²CMAP, Ecole Polytechnique, Paris, France, ³INRIA, Paris, France

The 4D dynamic simulation of perfusion and diffusion lesion evolutions in acute-subacute ischemic stroke has considerable prognostic potential. We applied a current-based, 4D, dense, diffeomorphic regression model to perfusion and diffusion MR images acquired at three successive timepoints after stroke. The evaluation of the 4D patient-specific perfusion-diffusion evolution scenarios of 8 representative patients was promising as it fitted the reference standard manually-delineated lesion boundaries. Meanwhile, the dynamic spatio-temporal and kinetic contraction/expansion stroke lesion behavior did not fit with the expected lesion evolution as expected from the “perfusion-diffusion mismatch” hypothesis commonly used in stroke treatment.

Anja G van der Kolk¹, J Martijn Nobel², Jaco JM Zwanenburg¹, Fredy Visser¹, Peter R Luijten¹, and Jeroen Hendrikse^1
1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, ²University Utrecht, Utrecht, Netherlands

Fluid-Attenuated Inversion Recovery (FLAIR)-imaging is one of the mainstays of current cerebral diagnostic protocols. At 7.0 Tesla (7T) MRI, SNR increases, theoretically increasing both localization accuracy and lesion conspicuousness of FLAIR-sequences. However, so far, these advantages have only been assessed in healthy volunteers. In this study, clinically obtained 1.5T FLAIR-imaging were compared to FLAIR-imaging at 7T in 10 patients with cerebrovascular disease. Overall quality of both sequences were comparable, although field inhomogeneity artifacts were more severe at 7T. Both sequences adequately distinguish pathology from healthy tissue. These results show that 7T FLAIR-imaging can be used in the clinical setting.

Pauline Roca¹, Edjlali-Goujon Myriam¹, Cécile Rabrait², Kevin M. Johnson³, Oliver Wieben^3,4, Denis Trystram¹, Olivier Naggara¹, Jean-François Meder¹, and Catherine Oppenheim^1
1Department of Neuroradiology, Sainte-Anne Hospital, University of Paris Descartes, UMR S894, Paris, France, ²GE Healthcare, Vélizy, France, ³Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, United States, ⁴Department of Radiology, University of Wisconsin, Madison, Wisconsin, United States

In this preliminary study, we assessed the clinical usefulness of a three-dimensional phase contrast MR pulse sequence (PC VIPR) with two different encoding speed settings (Venc30=30cm/s and Venc80=80 cm/s) in two patients with brain vascular disorders (an arterio-venous malformation with an intranidal ectasia and a dural arterio-venous fistula) in a realistic clinical acquisition time (9 min). Venc30 and Venc80 provided complementarly with a complete intracranial arterial and venous coverage which could be of great help for diagnostic, prognostic purposes and therapeutic decision.: vascular anatomy visualization with high isotropic spatial resolution (0.85 mm3) distinguishing small intranidal structures and quantitative blood flow measurements detecting abnormal high speed vessels.

Michael Kelly^1,2, Matthew Rowland^1,2, Thomas Okell¹, Michael Chappell³, Jon Westbrook², Peter Jezzard¹, and Kyle Pattinson^1,2
1FMRIB Centre, University of Oxford, Oxford, United Kingdom, ²Nuffield Dept of Anaesthetics, University of Oxford, Oxford, United Kingdom, ³Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom

Delayed cerebral ischaemia (DCI) is the main cause of mortality following subarachnoid haemorrhage (SAH). Early brain injury following SAH can lead to reductions in cerebral blood flow (CBF) and may indicate DCI. We investigate the use of pseudo-continuous ASL (pCASL) to measure CBF in the acute phase post SAH. 6 patients were scanned on multiple occasions. A global decrease in CBF was detected on day 3 post SAH in one patient. This perfusion deficit was not detected by routine clinical assessment. The findings suggest measurement of CBF by pCASL can play a role in identifying patients at risk of DCI.

Andrew J Patterson¹, Andrew J Degnan¹, Martin J Graves¹, Tjun Y Tang², and Jonathan H Gillard^1
1Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, England, United Kingdom, ²Department of Vascular Surgery, Cambridge University Hospitals NHS Foundation Trust, Cambridge, England, United Kingdom

A long-term follow-up study assess if USPIO intra-plaque uptake is predictive of subsequent cerebrovascular and cardiovascular events. Sixty-two patients were followed for a median of 4 years in which 17 patients had subsequent events. Survival regression models are applied to assess if signal intensity change following USPIO is predictive of events.

Zahari Tchopev¹, Jiachen Zhuo¹, Josh Betz¹, Rao Gullapalli¹, and Kevin N. Sheth^2
1Magnetic Resonance Research Center, Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States, ²Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland, United States

Early identification of patients at risk for neurological deterioration following stroke remains a challenge. Retrospective analysis on 28 patients with cerebellar stroke was performed to identify whether the combined information from cerebellar lesion volume defined on DWI-MRI, cerebellar ADC values, and the NIH stroke scale score would serve as prognostic indicators of clinical outcome. Logistic regression revealed relative cerebellar lesion volumes to be significant predictors of poor outcome, even when controlling for age, NIHSS score, and hours to scan. On average, patients with 30% involvement of the cerebellum (~41cc) were determined to have a poor outcome.

James Qiupeng Zhan¹, Alan Moody^1,2, Cristina Nasui², and Herve Jeufack^1
1Sunnybrook Hospital, Toronto, Ontario, Canada, ²Medical Imaging, University of Toronto, Toronto, Ontario, Canada

To assess whether 3D MRIPH and 3D TOF MRA at 3T could be used for arterial wall evaluation independent of 2D multi-contrast MRI sequences. 10 patients were scanned and acquired 3D High-Spatial-Resolution MRIPH, 3D TOF, and 2D multi-contrast MRI. Lumen boundary on 3D TOF and outer wall boundary on 3D MRIPH were segmented, as well as on the 2D multi-contrast images. There is very close agreement between 3D MRIPH combined with 3D TOF MRA when compared to the 2D multi-contrast MRI. This methods give a thorough description of atherosclerotic vessel wall disease. It potentially overcomes some problems of prolonged scan time and registration of images from multiparametric 2D data sets.

Justin Vranic¹, Parmede Vakil², Ali Habib², Alexander Korutz², Michael C Hurley², Timothy J Carroll², and Sameer A Ansari^2
1Northwestern University, Chicago, IL, United States, ²Northwestern University

Following acute ischemic stroke, accurate evaluation of current and future tissue infarction is essential to patient outcomes. Using Bookend dynamic susceptibility contrast perfusion weighted imaging (DSC-MR PWI) to measure quantitative cerebral blood flow (qCBF), we investigated the ability of qCBF to predict future tissue infarction in acute stroke patients. In this retrospective study, we report that cerebral tissue that infarcted within 72 hours of initial imaging had a qCBF of 14.51±0.41 ml/100g/min whereas tissue that survived had a qCBF of 16.85±0.06 ml/100g/min. These results indicate that appropriate qCBF thresholds may be able to serve as accurate predictors of tissue infarction.

Steven Mocking^1,2, Raquel Bezerra¹, Elissa McIntosh¹, Izzudin Diwan¹, Priya Garg¹, William Taylor Kimberly³, Ethem Murat Arseva¹, Hakan Ay¹, Aneesh B Singhal³, William A Copen⁴, Pamela Schaefer⁴, and Ona Wu^1
1Athinoula A. Martinos Center for Biomedical Imaging, Dept. of Radiology, MGH, Charlestown, MA, United States, ²Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands, ³Dept. of Neurology, MGH, Boston, MA, ⁴Dept. of Radiology, MGH, Boston, MA

We validated five algorithms for segmenting DWI lesions in acute ischemic stroke on an independent dataset and investigated the proportion of acutely misclassified tissue with follow-up manual outlines. Performance of the algorithms on the validation dataset was comparable to results on the training dataset, with the naive Bayes approach providing best sensitivity and Dice similarity coefficient. In many cases, several voxels classified as lesion or normal by the automatic algorithms but not by the manual outliner were found respectively to be infarcted or normal on follow-up imaging. Consequently, apparent misclassification may partially be a result of reader variation.

Jian Chen¹, Shaloos Singhal^1,2, Henry Ma², John Ly², and Thanh G Phan^1,2
1Department of Medicine, Monash University, Melbourne, VIC, Australia, ²Stroke Unit, Monash Medical Centre, Melbourne, VIC, Australia

The regions at risk of ischemic injury following cardiorespiratory arrest have not been systematically analysed. In present study we use the digital probabilistic method and principal component analysis to study topography of ischemic injury following cardiorespiratory arrest. In the probabilistic atlas , the highest frequency of ischemic injury was caudo-putamen (0.250), temporal lobes (0.0175), occipital (0.0150) and hippocampus (0.125). The first component showed covariance between the deep gray matter nuclei and posterior cortical structures . The two different methods show similarity in their emphasis on the deep gray matter nuclei and the posterior cortical structures.

Kay Jann¹, Manuela Wapp², Patrik Michel³, Marwan El-Koussy², Frauke Kellner-Weldon², Martinus Hauf², Gerhard Schroth², and Andrea Federspiel^1
1Dept. of Psychiatric Neurophysiology, University Hospital of Psychiatry / University of Bern, Bern, Bern, Switzerland, ²Institute for Diagnostic and Interventional Neuroradiology, Inselspital / Bern University Hospital, Bern, Bern, Switzerland, ³Dept. of Neurology, University Hospital Lausanne, Lausanne, Lausanne, Switzerland

In carotid artery disease (CAD) information about cerebral blood flow assessed by pCASL identified brain areas with reduced cerebro-vascular reserve capacity (CVR) due to the occlusion of a feeding vessel. A reduction of CVR was associated to cognitive deficits in CAD. In this study we investigated whether revascularization therapy restores CVR in the affected vascular flow territories in a 12 month follow up. Our results indicate the ability of revascularisation therapy to restore CVR in patients with CAD. Specifically, the CVR of the anterior watershed area was markedly increased after intervention

Harald Kramer¹, Val M Runge², John N Morelli³, Bernd J Wintersperger⁴, Maximilian F Reiser¹, and Birgit Ertl-Wagner^1
1Department of Clinical Radiology, University Hospital Munich, Munich, Bavaria, Germany, ²Department of Radiology, University of Texas Medical Branch, ³Department of Radiology, Scott and White Memorial Hospital, ⁴Department of Medical Imaging, UHN, MSH and WCH, University of Toronto

Diffusion weighted imaging (DWI) is used for the detection of acute brain ischemia in clinical routine. The drawback of single-shot EPI DWI is the reduced spatial resolution which impairs the exact anatomical allocation of an ischemic area. Introduction of multi-shot EPI DWI sequences can help to overcome this limitation.

Parmede Vakil¹, Ali Habib², Justin Vranic², Alexander Korutz², Ali Shaibani², Michael C Hurley², Timothy J Carroll², and Sameer A Ansari^2
1Biomedical Engineering, Northwestern University, Chicago, IL, United States, ²Northwestern University

Intracranial plaque enhancement due to vessel wall inflammation and subsequent contrast uptake can be visualized on T1 weighted MR images. Many studies have linked carotid vessel plaque enhancement with higher incidence of stroke; however little work has examined this relationship within the intracranial vasculature. Patients with severe atherosclerotic disease in the intracranial vasculature who received T1 imaging pre and post contrast injection were identified through a retrospective chart review. Plaques were scored on a 1-5 scale indicating degree of enhancement. We found that enhancing plaques were 86% more likely to be symptomatic.

Ona Wu¹, Kenneth K. Kwong¹, William A. Copen², Thomas Benner¹, Timothy G. Reese¹, Megan M. Aleardi³, Pamela W. Schaefer², and Aneesh B. Singhal^3
1Athinoula A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, ²Department of Radiology, Massachusetts General Hospital, Boston, MA, United States, ³Department of Neurology, Massachusetts General Hospital, Boston, MA, United States

Oxygen extraction fraction (OEF) increases in tissue at risk of infarction. Since R2 is related to OEF, we investigated the utility of measuring R2 with an asymmetric spin echo sequence in stroke patients imaged within 48 hours of onset. We found that R2 was very heterogeneous, decreasing in some patients (most notably those imaged post-thrombolysis), while increasing in others. Increased R2 appears to be associated with subsequent infarction, while decreased R2 is associated with both good and poor outcome. R2 may be useful for predicting tissue fate in combination with cerebral blood flow and cerebral blood volume.

Matthew Ethan MacDonald^1,2, Parviz Dolati^2,3, Linda Andersen^2,3, Cheryl R McCreary^2,3, John Wong^2,3, and Richard Frayne^2,3
1Biomedical Engineering, University of Calgary, Calgary, AB, Canada, ²Seaman Family MR Research Centre, Foothills Medical Centre, Alberta Health Services, Calgary, AB, Canada, ³Radiology and Clinical Neurosciences, University of Calgary, Calgary, AB, Canada

In this work we demonstrate the measurement of cerebral perfusion rapidly during neurovascular intervention with arterial spin labeling. A canine model for transient carotid vessel occlusion using endovascular devices is explained. Measures of different vascular territories are performed during carotid vessel occlusion. The temporal course of perfusion is evaluated during the stroke. Collateral flow is shown to sufficiently supply blood to the cortical regions, but flow is detectably lower in white matter during the stroke.

S. Beladi^1,2, C. R. McCreary^1,2, E. E. Smith^1,3, M. L. Lauzon^1,2, M. E. MacDonald¹, and R. Frayne^1,2
1Seaman Family MR Centre, Foothills Medical Centre, Alberta Health services, Calgary, Alberta, Canada, ²Department of Radiology, University of Calgary, Calgary, Alberta, Canada, ³Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada

This study evaluates the diagnostic values of susceptibility weighted imaging (SWI) and quantitative susceptibility mapping (QSM) for cerebral microbleed (CMB) detection in CAA patients. The QSM technique was implemented using L1-norm nonlinear regularization to accurately estimate the iron (hemosiderin) quantity in CMBs. A radiologist resident detected the QSMs and region of interest (ROI) study was performed on eighty randomly selected ROIs, containing a CMB and some surrounding normal tissue. According to the statistical results, QSM was proposed as an improved approach, which results in higher signal change between CMB and the surrounding tissue, reveals the actual size of the CMBs and provides quantitative measures that are independent of the imaging parameters.

Iain D Wilkinson¹, Tim Hughes¹, Josie M Reeve¹, Elaine Cachia¹, Daniel Warren¹, Paul D Griffiths¹, Solomon Tesfaye², and Dinesh Selvarajah^2
1Academic Radiology, University of Sheffield, Sheffield, S Yorkshire, United Kingdom, ²Diabetes, Royal Hallamshire Hospital, Sheffield, S Yorkshire, United Kingdom

Increased stroke risk in diabetes highlights the importance of internal carotid artery (ICA) functional status. ICA flow was assessed in 13 type-2 diabetics, 12 with impaired glucose tolerance (IGT, pre-diabetes) and 18 healthy volunteers (HV) using quantitative PCA before and after pharmacological stress. Resting ICA velocity was significantly lower in diabetics compared to HV’s (p=0.05). All groups demonstrated significant increases in flow and velocity post-acetazolamide (p=<0.001). ICA-cerebrovascular reserve was greater in HV [59(15)%] than diabetics [46(16)%; p<0.05] and IGT [40(20)%; p<0.01]. These results suggest macrovascular cerebral abnormalities in those susceptible to, as well in, diabetes, indicating possible autoregulatory dysfunction.

Raquel da Cruz Bezerra¹, William A. Copen², Elissa McIntosh¹, Izzuddin Diwan¹, Priya Garg¹, Steven Mocking¹, Taylor W. Kimberly³, Ethem Murat Arsava¹, Ruijun Ji³, Hakan Ay¹, Aneesh B. Singhal³, Pamela W. Schaefer², and Ona Wu^1
1Radiology, MGH, Athinoula A Martinos Center for Biomedical Imaging, Boston, MA, United States, ²Radiology, Massachusetts General Hospital, Boston, MA, United States,³Neurology, Massachusetts General Hospital, Boston, MA, United States

We investigated the relationship between proximal arterial occlusion/stenosis on CTA and DWI-PWI mismatch in acute ischemic stroke patients (N=95). The sensitivity of proximal occlusion/stenosis in predicting DWI-PWI mismatch was 84% [95% CI: 72-92%] for MTT, and 85% [73-93%] for Tmax. The specificity of proximal occlusion/stenosis in predicting mismatch was 67% [48-81%] for MTT and 68% [49-82%] for Tmax. One third of patients without occlusion/stenosis had mismatch. Approximately 20% of patients with occlusion/stenosis did not exhibit mismatch. Therefore, a combination of vessel imaging and PWI would be pertinent for selecting patients likely to benefit from extended time-window therapies.

Julien Bouvier^1,2, Marjorie Villien^1,3, Sylvie Grand^3,4, Assia Jaillard^4,5, Olivier Detante^1,4, David Chechin², Jean-Francois Le Bas^4,5, Alexandre Krainik^1,4, Emmanuel L Barbier^1,3, and Irene Tropres^5
1Grenoble Institute of Neurosciences, Grenoble, France, ²Philips Healthcare, Suresnes, France, ³INSERM U836, Grenoble, France, ⁴CHU Grenoble, Grenoble, France, ⁵3T Facility, SFR Biomedical NMR and Neurosciences, Grenoble, France

Local oxygen saturation maps (lSO2) may be obtained using separate estimates of T2, T2*, blood volume fraction (BVf), and B0 inhomogeneities. In this study, we collected lSO2 and perfusion maps (BVf and CBF) in seven stroke patients six weeks after stroke. CBF is higher in the contralateral area than in its periphery and in the non-necrotic pixels of the lesion, while BVf values are comparable between these three regions. The reduced lSO2 in the lesion is consistent with the lower CBF observed in this area and may be the sign of a glial inflammatory scar.

Tobias Verleger¹, Dennis Säring¹, Michael Schönfeld², Susanne Siemonsen², Jens Fiehler², and Nils Daniel Forkert^1
1Department of Computational Neurosience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, ²Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Germany

Intra-patient registration of Time-of-Flight MRA image sequences is required for several quantitative analyses and therapy monitoring of cerebrovascular diseases. The aim of this study was to evaluate different rigid registration approaches for aligning TOF MRA image sequences. For this, eight rigid registration approaches were evaluated with the target registration error (TRE) calculated based on 308 landmarks defined in twenty TOF datasets. Each dataset included a baseline and follow-up image sequence. The results revealed that the highest registration accuracies can be achieved using a multi-resolution framework and a cerebrovascular segmentation as a mask with a mean TRE of 1.1mm.

Amanda Kathleen Wake Buck¹, Manus Donahue¹, J. Christopher Gatenby², Elizabeth Yang³, Carlton Dampier⁴, and John C. Gore^1
1Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, ²University of Washington, ³Vanderbilt University, Nashville, TN, United States, ⁴Emory University

Large vessel flow and microvascular perfusion distributions were investigated in pediatric sickle cell anemia patients with/without Moyamoya corrective surgery in the context of large vessel configurations.

Kazuhiro Nakamura¹, Takumi Takahashi², Yasushi Kondoh¹, Guoyue Chen², and Toshibumi Kinoshita^1
1Akita Research Institute for Brain and Blood Vessels, Akita, Akita, Japan, ²Akita Prefectural University, Ugohonjo, Akita, Japan

Diffusion weighted imaging with typical single refocused pulsed-gradient spin-echo (SRSE-DWI) sequence is interacted by susceptibility-induced background gradient fields around vessels, while the effect is reduced in twice-refocused spin-echo (TRSE-DWI) sequence. The difference between SRSE-DWI and TRSE-DWI will indicate CBV weighted image. We evaluated the ADC reduced ratio in both sequence with Monte-Carlo simulations in a vascular model. The results indicate effective criteria for brain stroke validation from diffusion weighed image of twice-refocused spin-echo sequence.

Toshiteru Miyasaka¹, Toshiaki Taoka², Tomoko Ochi², Toshiaki Akashi², Kaoru Myochin², Takeshi Wada², Katsutoshi Takayama², Hiroyuki Nakagawa¹, and Kimihiko Kichikawa^2
1Department of Radiology, Nara prefectural Nara hospital, Nara, Nara, Japan, ²Department of Radiology, Nara medical university, Kashihara, Nara, Japan

Magnitude images of SWI depicted the majority of the draining veins of dAVF as much bright intensity as TOF MRA. Draining veins, which disappeared on angiography after the treatment, showed lower signal intensity than before treatment on magnitude images and TOF MRA. We speculate that higher concentration of oxy-Hb within draining veins is one of the causes of high signal intensity on magnitude images and the signal intensity was lower after the treatment due to decreased velocity and lower concentration of oxy-Hb on magnitude images.

Julien Bouvier^1,2, Florence Tahon³, Irène Troprès⁴, Omer Eker³, David Chechin², Jean-François Le Bas^3,4, Alexandre Krainik^3,5, and Emmanuel Luc Barbier^1,5
1INSERM U836, Grenoble, Isère, France, ²Philips Healthcare, Suresnes, Ile de France, France, ³CHU, Grenoble, France, ⁴3T Facility, SFR Biomedical NMR and Neurosciences, Grenoble, France, ⁵Université Joseph Fourier, Grenoble Institute of Neurosciences, Grenoble, France

Quantitative Blood Oxygen Level Dependent allows quantitative evaluation of cerebral tissue hemodynamic parameters, such as the blood volume (BVf), deoxyhemoglobin concentration or local oxygen saturation (lSO2). An approach that combines separate estimates of T2, T2*, BVf and B0 inhomogeneities has recently been proposed and validated in rats. The aim of this study is to evaluate this approach in patients bearing an arteriovenous malformation (AVM) and evaluate the oxygenation status in the tissue surrounding the AVM nidus.

Yuan Huang¹, Zhongzhao Teng^1,2, Umar Sadat^1,3, Victoria E. Young¹, Martin J. Graves¹, and Jonathan H. Gillard^1
1Department of Radiology, University of Cambridge, Cambridge, United Kingdom, ²Department of Engineering, University of Cambridge, Cambridge, United Kingdom,³Cambridge Vascular Unit, Addenbrooke's Hospital, Cambridge, United Kingdom

The traditional hypothesis that plaque rupture occurs when the external loading exceeds the fibrous cap strength has shown its limitations. In this study an alternative mechanism of rupture, material fatigue, was investigated based on in-vivo MR images. Slices with rupture and ulceration obtained from fourteen patients with carotid atherosclerotic disease were used for the simulation. Crack growth was quantified using modified Paris Law. The predicted crack initiations all matched with the in-vivo observation, and 12 /14 models showed the crack in accordance with in-vivo images. Further results showed the fatigue life decreased rapidly with smaller fibrous cap thickness.

Virginie Callot¹, Guillaume Duhamel¹, Jérôme Laurin², André Mauès de Paula³, and Patrick J Cozzone^1
1CRMBM, CNRS, Aix-Marseille Univ, Marseille, France, ²ISM, CNRS, Aix-Marseille Univ, Marseille, France, ³Service d’Anatomie Pathologique, Hôpital de la Timone, AP-HM, Marseille, France

Blood perfusion plays a crucial role in spinal cord injury, however measurements of SC hemodynamics are scarce. In this study, the potentiality of the Intra Voxel Incoherent Motion (IVIM) technique, which is a diffusion-based method that can easily be performed in most scanners, was evaluated in healthy and injured mouse models. IVIM allowed collecting normal and pathological diffusion measurements and perfusion indices. For injured mouse, the posttraumatic evolution of the vascular IVIM indices was additionally correlated with ASL-based SCBF values. Further investigation is worthy since IVIM may constitute an alternative method to get SC vascular descriptions and pathological characterizations.

Virginie Callot¹, Léo Fradet^2,3, Jean-Philippe Ranjeva¹, Patrick J Cozzone¹, Pierre-Jean Arnoux², and Yvan Petit^3,4
1Centre de Résonance Magnétique Biologique et Médicale (CRMBM), CNRS, Aix-Marseille Univ, Marseille, France, ²Laboratoire de Biomécanique Appliquée (LBA), INRETS, Université de la Méditerranée, Marseille, France, ³Department of Mechanical Engineering, Ecole de Technologie Supérieure (ETS), Montréal, Canada, ⁴Research Center, Hôpital du Sacré-Coeur, Montréal, Canada

Most of the recent finite element models (FEM) of the human spinal cord (SC) are based on postmortem specimens’ geometry measured on a few vertebral segments. The present study, based on MR examination of cervical and thoraco-lumbar SC of healthy volunteers, was undertaken to identify recurrent features among individuals and to determine if post mortem measurements are likely to significantly represent in vivo geometric characteristics of the spinal cord. Four parameters have been determined as good morphometric standards (inter-subject and in vivo/postmortem), which open the perspective of creating patient specific refined virtual model of the spinal cord.

Yunyan Zhang¹, Axinia Doering², and V Wee Yong^3
1Depts of Radiology and Clinical Neurosciences, University of Calgary, Calgary, AB, Canada, ²Dept of Paediatrics, University of Calgary, Calgary, AB, Canada, ³Dept of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada

Twelve mice with induced demyelination and spontaneous remyelinaiton in dorsal spinal cord were imaged at day 0 (intact myelin), and at 7 (demyelination), 28 and 35 (remyelination) days post injury. MRI texture was assessed in lesions and control white matter of the spinal cord over time. We found that the change in MRI texture parallels that of demyelination and remyelination. While lesion area demonstrates similar evolving pattern texture analysis further suggests the presence of residual injury at day 35 despite significant remyelination. MRI texture analysis may be a promising measure of myelin pathology, which warrants further verification.

Blake E. Dewey^1,2, Ha-Kyu Jeong², Jane A.T. Hirtle^2,3, Adam W. Anderson^2,4, John C. Gore^2,5, and Seth A. Smith^2,5
1Physics and Astronomy, Vanderbilt University, Nashville, TN, United States, ²Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, ³Psychology and Human Development, Vanderbilt University, Nashville, TN, United States, ⁴Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, ⁵Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States

In the human cervical spinal cord, cardiac motion and field inhomogeneities challenge EPI-based DTI acquisitions. Here, we compare the impact of not only gating on single-shot (SSH), but also present a gated/non-gated comparison of a novel 2D navigated multi-shot (MSH) EPI DTI acquisition. Tractography from only one seed ROI 2D DTI-derived index maps and whole cord mean ± SD comparisons are evaluated. The impact of gating resulted in greater robustness of the PEV and extent of tractography, yet 2D navigated MSH DTI showed largely minimized SSH distortion. Reproducibility analysis is necessary to clarify the accuracy of the derived metrics.

Patrick W Stroman¹, Rachael L Bosma¹, Christine Dobek¹, and Michaela Beynon^1
1Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada

Verification of the reliability of functional maps obtained with spinal cord fMRI in individuals is necessary before this method can be used for clinical studies of the effects of injury or disease on spinal cord function. A study of the test-retest consistency of activity detected in the spinal cord in response to thermal sensory stimulation was carried out in 11 healthy participants. Results demonstrate that activity maps are reliable in individuals, with consistent activity being detected within the same quadrants of spinal cord segments across studies repeated 1 week apart.

Faith H. Reece¹, Nyoman D. Kurniawan², Gary J. Cowin², and Marc J. Ruitenberg^1,3
1School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia, ²Centre for Advanced Imaging, The University of Queensland, Brisbane, Queensland, Australia, ³The Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia

Abstract Following spinal cord injury (SCI), various cellular and molecular events worsen the primary damage by compromising nearby neurons that were originally spared. This study utilised diffusion tensor imaging (16.4T Bruker NMR scanner) to evaluate secondary injury development in a mouse model of contusive SCI. In the spared white matter, fractional anisotropy and axial diffusivity decreased while transverse diffusivity increased with time and proximity to the lesion. Cord integrity was most compromised at the dorsal columns whereas the ventral and lateral funiculi progressively degenerated. Therapeutic intervention designed to counteract secondary degeneration would be most efficient 2 hours-1 day post-injury.

Daniel J. Tozer¹, Marios C. Yiannakas¹, Hugh Kearney¹, and Claudia A. M. Wheeler-Kingshott^1
1NMR Research Unit, Department of Neuroinflammation, UCL Institute of Neurology, London, London, United Kingdom

The work presented here shows a method for developing a cervical spinal cord template of healthy controls that can become a future reference for clinical studies. Three axial scans from five subjects were trimmed to retain a volume only 50x50mm2 surrounding the cervical cord. The images were registered and averaged to produce a template, showing details such as the internal grey matter structures. The template presented here will improve with the addition of more healthy subjects. The methodology used here can be retained for group analysis of quantitative imaging, although use in patient studies may require some degree of adaptation.

Rebecca S Samson¹, Marios C Yiannakas¹, Mara Cercignani², Xavier Golay³, and Claudia A M Wheeler-Kingshott^1
1NMR Research Unit, Department of Neuroinflammation, UCL Institute of Neurology, London, England, United Kingdom, ²Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, University of Sussex, Brighton, United Kingdom, ³Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, England, United Kingdom

The Magnetisation Transfer Ratio (MTR), and quantitative Magnetisation Transfer parameters have proven to be sensitive to the diseased spinal cord (SC). However, SC imaging can be challenging. Rapid acquisition sequences such as Echo Planar Imaging (EPI) are desirable but may suffer from artefacts and image distortions. We present results using multi-shot gradient echo EPI and ZOOM EPI for time reduction in SC MTR and compare image quality and reproducibility with the ‘gold standard’ spoiled gradient echo. ZOOM EPI results in superior image quality than multi-shot EPI, with less artefacts and good inter- and intra-subject reproducibility in whole cord MTR measurements.

Juan Jose Herrera¹, and Ponnada A. Narayana^1
1Department of Diagnostic and Interventional Imaging, UTHealth Medical School, Houston, TX, United States

Spinal cord injury (SCI) results in the disruption of the blood spinal cord barrier (BSCB) allowing blood-borne molecules and cells to enter into the injured parenchyma triggering secondary damage beyond the site of original injury. Our study demonstrated that promoting stabilization of the BSCB through the acute intraspinal administration of angiopoietin-1, a vascular stabilizing protein, reduced vascular permeability leading to improved functional recovery. We examined the temporal change of BSCB permeability using dynamic contrast enhance MRI and in parallel performing neurobehavioral assays.

Jason F Talbott¹, Yvette Nout², Michael Wendland¹, Pratik Mukherjee¹, Jacqueline Bresnahan^3,4, and Michael Beattie^3,4
1Radiology, UCSF, San Francisco, CA, United States, ²Animal and Veterinary Sciences, California State Polytechnic University Pomona, Pomona, CA, ³Neurological Surgery, UCSF, San Francisco, CA, ⁴Brain and Spinal Injury Center, San Francisco, CA

Recent literature suggests that diffusion weighted imaging may distinguish demyelination from white matter injury with associated axon injury, thus serving as a powerful in-vivo biomarker for white matter integrity. Using a model of focal axon-sparing demyelination, we evaluate diffusion parameters utilizing in-vivo MRI with correlative histologic and immunohistochemical analysis. Further, demyelinating injury is compared with severe white matter contusion injury during acute and chronic time points. Interestingly, we find that diffusion parameters are sensitive, but not specific markers of white matter injury and cannot distinguish pure demyelination from severe combined axonal and myelin white matter injury during the acute phase.

Andreas Hock¹, Nassos Petrou², Peter Zweers², Erin L. MacMillan³, Roland Kreis³, Peter Boesiger¹, and Anke Henning^1
1University and ETH Zurich, Institute for Biomedical Engineering, Zurich, Switzerland, ²Diagnostic radiology and neuro-radiology, Swiss Paraplegic Centre, Nottwil, Switzerland,³University of Bern, Dept. of Clinical Research, Bern, Switzerland

Magnetic resonance spectroscopy (MRS) enables determination of metabolite concentrations and thus allows for early detection of pathological processes. It may identify clinically relevant biomarkers that predict response to different therapy options for personalized patient treatment which is of specific interest in patients with traumatic injuries in the spinal cord. The aim of this investigation was to demonstrate the feasibility of 1H MRS in the spinal cord of patients with traumatic injury and to characterize specific changes in the metabolic fingerprint. The results show a reduced NAA/Cre ratio which might be a marker for the degree of syringomyelia, nerve cell damage, cord degeneration or cavity formation.

Marios C Yiannakas¹, Hugh Kearney¹, David H Miller¹, and Claudia A.M Wheeler-Kingshott^1
1Neuroinflammation, UCL Institute of Neurology, London, United Kingdom

A new acquisition protocol is presented here which employs phase sensitive inversion recovery (PSIR) reconstruction in conjunction with a commonly used 3D T1-weighted acquisition in order to improve reproducibility of cross-sectional area measurements in the cervical cord. The new protocol is optimised in a phantom that simulates the spinal cord and subsequently evaluated in five healthy volunteers. The images obtainable with the use of the proposed acquisition protocol allow measuring the cord area with results comparable to existing protocols, with the additional benefit of highly reproducible measurements.

Xiaojie Wang¹, Tsang-Wei Tu², Yong Wang³, and Sheng-Kwei Song^3
1Chemistry, Washington University, Saint Louis, Missouri, United States, ²Mechanical, Aerospace and Structural Engineering, Washington University, Saint louis, Missouri, United States, ³Radiology, Washington University, Saint louis, Missouri, United States

Ex vivo DBSI was performed on mice cords 3 and 14 days post contusion injury on T10 vertebral level. The extend of axon injury, demyelination, inflammation, and tissue loss were estimated using diffusion basis spectrum imaging derived directional diffusivity, cell ratio and water ratio, respectively. In addition to significant axon injury and demyelination, increased cellularity and water component were also observed in injured cords at both time points. DBSI findings are consistent with reported cellular response to SCI, suggesting DBSI could be used as the MRI method simultaneously visualizing axon and myelin integrity, inflammation and tissue loss in white matter.

Rebecca S Samson¹, Laura Brightman², Olga Ciccarelli³, Carolina Kachramanoglou³, Antoine Lutti⁴, David J L Thomas⁵, Nikolaus Weiskopf⁴, and Claudia A M Wheeler-Kingshott^1
1NMR Research Unit, Department of Neuroinflammation, UCL Institute of Neurology, London, England, United Kingdom, ²University of Cambridge, Cambridge, United Kingdom,³NMR Research Unit, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, England, United Kingdom, ⁴Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, England, United Kingdom, ⁵Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, England, United Kingdom

Quantitative MRI techniques have been shown to be sensitive to changes in diseased spinal cord via measurements of relaxation times, the Magnetisation Transfer Ratio (MTR), and more recently quantitative Magnetisation Transfer (MT) parameters. However, in order to make tissue-specific quantitative measurements within the cord a robust co-registration is required. We investigated various linear registration methods within the FSL software package for co-registration of multi-modal cervical cord MRI data and the optimum method was used to register multi-modal spinal cord data, thus allowing the estimation of multi-parameter map values in white and grey matter regions within the cord.

Verena Knobloch¹, Christian Binter¹, Peter Boesiger¹, and Sebastian Kozerke^1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

The acquisition of arterial and venous blood flow to the cranium as well as flow of cerebrospinal fluid (CSF) in the spinal canal are the main input parameters for modeling cerebrospinal dynamics. The acquisition of all three components requires high sensitivity to a large range of velocities. This work aimed at simultaneous measurement of arterial, venous and CSF flow in the neck using a multi-point variable-density velocity encoded 3D sequence with spatiotemporal undersampling. The net difference in arterial and venous blood flow is decreased with the use of the shown acquisition method compared to 2D Phase Contrast acquisition.

Shonit Punwani¹, Pierpaolo Purpura¹, Nikolaos Dikaios¹, Heather Fitzke¹, Alan Bainbridge², David Price², Scott Rice¹, Simon Morley³, Timothy Beale³, Ruheena Mendes⁴, Martin Forster⁴, Dawn Carnell⁴, Thayalini Vaitilingam³, Nina Newton¹, David Atkinson¹, Steve Halligan¹, and Stuart Taylor^1
1Centre for Medical Imaging, University College London, London, UK, United Kingdom, ²Medical Physics and Bioengineering, University College London Hospital, London, United Kingdom, ³Radiology, University College London Hospital, London, United Kingdom, ⁴Head and Neck Oncology, University College London Hospital, London, United Kingdom

The study assess multi-scale diffusion parameters (median volumetric nodal region of interest values, inter-voxel histogram distributions, and intra-voxel diffusion heterogeneity as assessed by the stretched exponential model) as classifiers of nodal status in patients with head and neck squamous cell carcinoma (SCC). Low b value (0, 50, 100) derived nodal ADC (perfusion sensitive) was the key parameter facilitating discrimination of metastatic from benign nodes in patients with head and neck SCC. The stretched exponential derived α value together with histogram features of ADC provide an accurate decision tree model for classification of nodal disease.

Eric R Muir¹, Yi Zhang¹, Oscar San Emeterio Nateras¹, and Timothy Q Duong^1,2
1Research Imaging Institute, UT Health Science Center, San Antonio, TX, United States, ²Ophthalmology, UT Health Science Center

This study aims to determine whether temperature gradient across the eye could affect T1-based vitreous pO2 measurement in humans by closing and covering the eye to reduce temperature gradients. Calibrations of T1 at different pO2 and temperatures were performed on water phantoms and ex vivo eyes. T1 maps and pO2 were obtained on human subjects with the eye open or closed/covered. Closing the eye caused T1 increase, so temperature effects on T1 in the eye may need to be accounted for. Closing the eye is a simple method to remove confounding temperature gradients across the vitreous for T1-based pO2 mapping.

Eric R Muir¹, Yi Zhang¹, Oscar San Emeterio Nateras¹, and Timothy Q Duong^1,2
1Research Imaging Institute, UT Health Science Center, San Antonio, TX, United States, ²Ophthalmology, UT Health Science Center

Abnormal vitreal oxygen tension (pO2) has been implicated in a number of ocular and retinal diseases. MRI could be used to non-invasively map pO2 of the human vitreous since T1 is affected by pO2. In this study MRI methods were developed to measure pO2 in the human vitreous using the Look-Locker sequence to rapidly measure T1 to minimize eye motion. Calibration of T1 to pO2 was made using ex vivo vitreous in addition to water phantoms to provide more accurate pO2 calculation from T1. Human vitreous pO2 was found to be 26.8±7.5mmHg with MRI, comparable to reports of invasive measurement.

Johanna J. Bluemink¹, Wouter Koning², Dennis W. Klomp², Peter R. Luijten², Frank A. Pameijer², Marielle Philippens¹, Jan J.W. Lagendijk¹, and Cornelis A.T. van den Berg^1
1Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands, ²Radiology, University Medical Center Utrecht, Utrecht, Netherlands

In this work we explore the possibilities of 7T MR imaging of the larynx for diagnosis of the extension of laryngeal tumors. Comparison with 3T imaging indicates that anatomical details such as the epithelial layer of the vocal cords can be imaged with high resolution (0.50.51mm³) at 7T, whereas at 3T the SNR is insufficient, resulting in noisy images. Therefore, at 3T thicker slices are needed leading to partial volume effects. As a result 7T imaging may provide useful additional information about tumor extent.

Sonja Monika Pivec^1,2, Eva Scheurer^1,2, Florian Fischer^1,2, Gerlinde Komatz³, Zoe Voigt⁴, Magdalena Webhofer⁵, Kathrin Yen⁶, and Thomas Ehammer^1
1Ludwig Boltzmann Institute for Clinical-Forensic Imaging, Graz, Austria, ²Medical University Graz, Graz, Austria, ³MRI Institute Private Clinic of the Holy Sisters, Graz, Austria,⁴Institute of Legal Medicine and Forensic Science, Charité, Berlin, Germany, ⁵Schön Clinic Harthausen, Clinic for Orthopedic Surgery, Germany, ⁶Institute for Forensic and Traffic Medicine, University of Heidelberg, Heidelberg, Germany

Victims of manual strangulation often present without any external injury. However, reliable diagnosis of strangulation and objective documentation of lesions are crucial for the criminal proceeding. While the feasibility of MRI of the neck in strangulation victims had already been shown, this study aimed at the evaluation of the diagnostic performance of a native MRI scan using a defined diagnostic scheme. The most frequent findings associated with strangulation were subcutaneous lesions and intramuscular bleedings. Using the diagnostic scheme strangulation was diagnosed with a high sensitivity and specificity. MRI might become an essential tool in the forensic assessment of survived strangulation.

Seong-Eun Kim¹, Eun-Kee Jeong¹, Xianfeng Shi², Gerald S Treiman^3,4, and Dennis L Parker^1
1UCAIR Department of Radiology, University of Utah, Salt Lake City, Utah, United States, ²UCAIR Brain Research Insititute, University of Utah, ³Department of Surgery, University of Utah, ⁴Department of Veterans Affairs, VASLCHCS

Hemorrhage is an important plaque component. It has been reported that Type I (fresh) hemorrhage occurred more often in patients with symptomatic plaques. It has been reported that T2* measurement distinguished symptom-producing from non-symptom producing plaques in patients. A previous ex vivo DWI study reported that the ADC in hemorrhage varies according to the processes that occur during the successive phases of aging. The purpose of this study was to determine retrospectively if T2* and ADC value obtained from a 2D ss-SGE-DWEPI sequence can simultaneously depict differences between symptomatic and asymptomatic carotid atherosclerotic plaque.

Marco Borri¹, Maria Schmidt¹, David Collins¹, Matthew Orton¹, James d'Arcy¹, Ceri Powell², Dow-Mu Koh^1,3, Angela Riddell³, Kate Newbold², and Martin O. Leach^1
1CR-UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden Hospital, Sutton, Surrey, United Kingdom, ²Head & Neck Department, The Royal Marsden NHS Foundation Trust, ³Radiology Department, The Royal Marsden NHS Foundation Trust

Reliability of functional parameters depends on accuracy of DCE modelling approaches, and the arterial input function is an important component of the perfusion model. In this work we compare two different approaches to measuring patient-specific AIF in the carotid artery: (i) using a pre-bolus (10% of the dose) prior to DCE acquisition and (ii) using a local enhancing vessel present in the DCE examination. Both approaches are compared in a cohort of patients with histologically proven head and neck carcinoma undergoing radical chemoradiotherapy and enrolled in a longitudinal study, and reproducibility and inter-patient variability are assessed.

Marielle E.P. Philippens¹, Johanna J. Bluemink², Sjoerd P.M. Crijns³, Jacco J.M. Zwanenburg⁴, Fredy Visser⁴, Frank A. Pameijer⁴, and Chris H.J. Terhaard^3
1radiotherapy, hp Q00.118, UMC Utrecht, Utrecht, Utrecht, Netherlands, ²Radiotherapy, UMC Utrecht, Utrecht, Utrecht, Nepal, ³Radiotherapy, UMC Utrecht, Utrecht, Utrecht, Netherlands, ⁴Radiology, UMC Utrecht, Utrecht, Utrecht, Netherlands

In cancer in the head and neck region, the facial (nVII) and trigeminal (nV) nerves can be affected by microscopic or macroscopic perineural growth. For radiotherapy treatment, the affected nerves have to be included in the target volume. Therefore, high resolution MR imaging is required of nV and NVII is needed. We used T2-FFE with a binomial water selective pulse for fat suppression. High resolution T2-FFE images with an excellent quality were acquired that allow to trace the cranial nerve pathways of nV and nVII in the head and neck region.

Sjoerd Crijns¹, Hanneke Bluemink¹, Jaco Zwanenburg², Fredy Visser², Homan Dehnad, ¹, and Marielle Philippens^1
1Imaging division, department of radiotherapy, UMC Utrecht, Utrecht, Utrecht, Netherlands, ²Imaging division, department of radiology, UMC Utrecht, Utrecht, Utrecht, Netherlands

We identify the requirements for a good MR neurography sequence and propose a 3D T2-FFE sequence with binomial RF pulses for water-selective excitation to selectively depict nerves. This sequence is applied to image head and neck region as well as lumbar spine and pelvic region in a series of healthy volunteers. Additionally, we compare conventional T2w STIR TSE imaging with the proposed 3D T2-FFE sequence in a patient with bone metastasis. Results illustrate feasibility of acquiring MR images of nerves at high resolution, in a large FOV within reasonable acquisition time and potentially added diagnostic value over the conventional sequences.

Tomasz Dawid Lindel^1,2, Andre Kuehne^1,2, Patrick Waxmann^1,2, Frank Seifert^1,2, Thoralf Niendorf², and Bernd Ittermann^1,2
1Medical Metrology, Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany, ²Max Delbrück Center for Molecular Medicine (MDC), Berlin Ultra-High Field Facility (BUFF), Berlin, Berlin, Germany

Spatially selective excitation (SSE) using multiple transmit channels offers the possibility of zoomed imaging, i.e., acquiring images of increased resolution within a reduced field of view and thus without scan time penalty. Hitherto, limited background suppression and anatomical contrast prevented widespread use of SSE in neuroimaging. With an improved SSE protocol on a 7T scanner with eight transmit channels we were able to mitigate some of these limitations. Arbitrary patterns were excited in the brain of a healthy volunteer and images with high T1 contrast were acquired. The background suppression was sufficient to allow zoomed imaging without noticeable aliasing.

Matthew P. Quinn¹, L. Martyn Klassen², Joseph S. Gati², and Ravi S. Menon^1,2
1Medical Biophysics, The University of Western Ontario, London, Ontario, Canada, ²Robarts Research Institute, London, Ontario, Canada

A novel post-processing scheme is presented for multi-echo susceptibility weighted imaging (SWI) that uses a mask derived from a frequency image. The performance of this frequency-based SWI is compared with two other previously reported multi-echo SWI schemes and single-echo SWI in healthy volunteers at 3 T. Frequency-based SWI shows significantly larger increases relative to single-echo SWI in signal to noise measured in frontal white matter, as well as in contrast to noise of periventricular veins, optic radiations, and globus pallidus, compared to previously described multi-echo SWI. In conclusion, frequency-based SWI shows improvements in visibility of a variety of field perturbers.

Deqiang Qiu¹, Thomas Christen¹, Wendy W Ni¹, Greg Zaharchuk¹, and Michael E Moseley^1
1Radiology, Stanford University, Stanford, CA, United States

Ultrasmall Superparamagnetic Iron Oxide (USPIO) is a strong T2* MR contrast agent that stays in the blood for long periods(~15hrs half-life). In this study, we explore the use of an FDA-approved USPIO compound ferumoxytol (labelled for treatment of iron-deficiency anemia) (AMAG Pharmaceuticals, Inc., Cambridge, MA) for enhanced visualisation of the vasculature. USPIO was demonstrated to have substantially improved detail of the smaller veins and vessels through a negative contrast. Tiny subcortical white matter lesions (“unidentified bright objects [UBO]”) appear relatively hyperintense structures in the USPIO-enhanced T2* images, suggesting low blood volume in UBOs. The use of persistant USPIO enhancement in the vasculature may aid in detection and characterization in many diseases.

Qiang Shen¹, Bianca Gonzales Cerqueira¹, and Timothy Q Duong^1
1Reseach Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States

Cerebral blood flow (CBF) is an important physiological parameter. The majority of CBF studies in rat brain are ~500x500x2000 microns using single shot EPI. The goal of this study is to image CBF of the rat brain at 75m x 56m x 1mm. Excellent CBF contrasts were observed among different cortical and sub-cortical structures. By constructing a digital atlas, CBF of 146 structures and their tissue volume were obtained automatically. This study sets the stage for investigating CBF dysfunction for a wide range of neurological diseases.

Zhifeng Kou¹, Hardik Doshi², Jie Yang³, Ramtilak Gattu³, Valerie Mika², Grace Ma⁴, Randall R Benson⁵, Robert Welch⁶, John Woodard⁷, Scott Millis⁸, and E Mark Haacke^1
1Biomedical Engineering and Radiology, Wayne State University School of Medicine, Detroit, MI, United States, ²Biomedical Engineering and Radiology, Wayne State University, Detroit, MI, United States, ³Radiology, Wayne State University, Detroit, MI, United States, ⁴Wayne State University School of Medicine, Detroit, MI, United States, ⁵Neurology and Radiology, Wayne State University School of Medicine, Detroit, MI, United States, ⁶Emergency Medicine, Wayne State University School of Medicine, Detroit, MI, United States, ⁷Psychology, Wayne State University, Detroit, MI, United States, ⁸Physical Medicine and Rehabilitation, Wayne State University School of Medicine, Detroit, MI, United States

By using susceptibility mapping as a means to quantify venous blood oxygen saturation, we found higher level of blood oxygen saturation in mild traumatic brain injury patients at the acute stage than that in controls.

Hugo J. Kuijf¹, Hendrik de Leeuw¹, Chris J.G. Bakker¹, and Koen L. Vincken^1
1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands

Interest in cerebral microbleeds is increasing rapidly, because they are associated with vascular disease and dementia. Detection of microbleeds on MRI is done manually, which is time-consuming and has limited reproducibility. Semi-automated detection will improve rating quality and decrease rating time. The radial symmetry transform performs excellent at this task, but has a number of false positives that need to be censored afterwards. By applying the radial symmetry transform on phase gradient magnitude images, the number of false positives can be reduced significantly. This will decrease the required rating time even further.

Natalia Petridou^1,2, Fredy Visser^1,3, Jaco JM Zwanenburg¹, Ben M Harvey⁴, Serge O Dumoulin⁴, and Peter Luijten^1
1Radiology, UMC Utrecht, Utrecht, Netherlands, ²Rudolf Magnus Institute, UMC Utrecht, Utrecht, Netherlands, ³Philips Medical Systems, Best, Netherlands, ⁴Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands

Recent work in non-human primates has shown enhanced in vivo visualization of subtle features of myeloarchitecture based on T1 contrast. Here, extending this work to humans, a 3D MPRAGE was optimized to enchance T1 contrast in high myelin content gray matter (GM) while suppressing signals from the remaining GM. We show excellent myelin visualization within GM in primary visual cortex, and spatially detailed T1 contrast variations in extra-striate visual cortex, possibly due to variations in myelin content as suggested by histology. This enhanced myelin sensitivity can bridge between in vivo functional imaging, and histological mapping of cortical micro-architecture in humans.

Eyesha Hashim¹, and Nicholas A Bock^1
1Medical Physics, McMaster University, Hamilton, Ontario, Canada

One way to study cortical organization is MRI of its myelin content. Myelin imaging of the cortex is challenging as myelin-contrast across the cortex is much lesser than myelin-contrast between the cortex and white matter. We have investigated optimization of MPRAGE, which is commonly used for structural brain imaging to achieve better intracortical contrast. We have found through simulation that increasing the time delay between acquisition blocks in MPRAGE can greatly increase intracortical contrast. In subjects imaged using this optimized sequence, we were able to delineate several primary areas on the digital surface extracted from anatomical scan.

José P. Marques^1,2, and Rolf Gruetter^2,3
1CIBM, University of Lausanne, Lausanne, Vaud, Switzerland, ²CIBM, EPFL, Lausanne, Vaud, Switzerland, ³CIBM, University of Lausanne and Geneva, Switzerland

T1 weighted brain imaging protocols are often designed to provide a good contrast to a large range of T1 values, from those of WM to those of CSF. In this work we show that the optimization of the contrast to a shorter range of T1’s can unveil interesting anatomical contrast often disregarded in T1 weighted imaging.

Hye Jin Jeong¹, Se Hong Oh¹, Jong Min Kim², Dae Hyuk Kown¹, Sung Yeon Park¹, Young Bo Kim¹, Beom S Jeon², and Zang Hee Cho^1
1Neuroscience Research Instiute, Gachon University of Medicine and Science, Incheon, Korea, ²College of Medicine, Department of Neurology, Seoul National University, Seoul, Korea

Parkinson¡¯s disease (PD) is a neurodegenerative disorder resulting from progressive loss of dopaminergic (DA) neurons in the substantia nigra (SN).Especially the degree of neuronal loss was significantly higher in the nigrosomes. We were directly investigated volume changes in the SN between the normal controls and PD patients by using 7.0T MRI. In the intermediate and caudal aspects, significant correlation was found subgroups of nigrosomes. The measured correlation analyses show that UPDRS motor score dependent correlation. Change of the SN structure has been regarded to hold greatest potential for use in the diagnosis of PD.

Francesca C Norris^1,2, Jack A Wells¹, Bernard M Siow^1,3, Simon Walker-Samuel¹, Peter J Scambler⁴, and Mark F Lythgoe^1
1UCL Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, United Kingdom, ²Centre for Mathematics and Physics in the Life Sciences and Experimental Biology, University College London, London, United Kingdom, ³Centre for Medical Image Computing, University College London, London, United Kingdom, ⁴Molecular Medicine Unit, UCL Institute of Child Health, London, United Kingdom

In the mouse, one third of genes are essential for development and disruption of these genes results in embryonic lethality. Therefore, advanced high-resolution 3D methods to detect the consequences of gene function in embryo development and diseases are crucial. MR imaging of mouse embryos is currently limited by a lack of tissue differentiation staining capabilities that provide flexibility and target specificity. In this study, we characterise the biodistribution and MR relaxation mechanisms of Mn-DPDP in ex vivo mouse embryos and identify this agent as a potential MRI ‘histological stain’ for embryonic cellular density.

Federico De Martino^1,2, Junqian Xu¹, Matthew Glasser³, David Van Essen³, Pierre-Francois van de Moortele¹, Rainer Goebel⁴, Elia Formisano⁴, Kamil Ugurbil¹, and Essa Yacoub^1
1Radiology, Center for Magnetic Resonance Research, Minneapolis, Minnesota, United States, ²Cognitive Neuroscience, Maastricht Univeristy, Maastricht, Netherlands,³Anatomy & Neurobiology, Washington University, St. Louis, Missouri, United States, ⁴Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands

In vivo MR anatomical contrast offers considerable promise for mapping cortical areas. Recently T1w and T2w images acquired at 3T were successfully combined to enhance myelin related anatomical contrast in vivo. At ultra-high fields (7 Tesla and above) anatomical contrast is enhanced and higher SNR permits higher spatial resolution images. we build on this idea of using ratio images to reduce intensity biases from the RF coil profile and show that mapping the ratio between T1 and T2* weighted images at 7T can reveal heavier myelination of several cortical areas in single subjects and high resolution.

Zaheer Abbas¹, Daniel P. Fiege¹, Irene Neuner^1,2, Christian C. Mirkes^1,3, Vincent Gras¹, Sandro Romanzetti¹, and N. Jon Shah^1,4
1Institute of Neuroscience and Medicine - 4, Forschungszentrum Jülich, Jülich, Germany, ²Department of Psychiatry, Psychotherapy and Psychosomatics, RWTH Aachen University, Aachen, Germany, ³Max Planck Institute for Biological Cybernetics, Tübingen, Germany, ⁴JARA - Faculty of Medicine, RWTH Aachen University, Aachen, Germany

Water content, or proton density (PD) and tissue sodium concentration (TSC) are tightly regulated in the human brain. A large number of diseases can be diagnosed and monitored observing these quantities. MRI protocols were set up to assess T1, T2*, PD and TSC quantitatively in vivo, and data from four healthy volunteers were acquired. Data were co-registered to the MNI brain and mean values for WM and GM structures were determined. Very good anatomical correspondence is achieved, despite combination of different imaging sequences.

Hao Huang^1,2, Tina Jeon¹, Takashi Yoshioka³, Virendra Mishra¹, Austin Chen³, Steven Hsiao³, Peter C van Zijl^4,5, and Susumu Mori^4,5
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States, ²Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States, ³Mind and Brain Institute, Johns Hopkins University, Baltimore, Maryland, United States, ⁴Department of Radiology, Johns Hopkins University, Baltimore, Maryland, United States, ⁵F.M.Kirby Research Center, Kennedy Krieger Institute, Baltimore, Maryland, United States

Comparison of gray matter volumes with MRI has provided us with insight on the anatomical evolution from non-human primates (M. mulatta) to humans. High resolution DTI was acquired from 10 in vivo macaques and 15 normal young human adults. DTI-tractography has been applied to trace 14 common major tracts in both macaque and human brains. Fractional anisotropy, mean diffusion, axial and radial diffusivity of these tracts were measured. These metrics characterizing the tract-level microstructures quantitatively were compared between macaque and human brain. Increased myelination of prefrontal, limbic white matter and left cortico-spinal tract was found from macaque to human brain.

Jeremy F P Ullmann¹, Andrew L Janke¹, Charles Watson², Nyoman D Kurniawan¹, George Paxinos³, Marianne D Keller¹, Zhengyi Yang¹, Kay Richards⁴, Gary F Egan⁵, Steve Petrou^4,6, Graham J Galloway¹, and David C Reutens^1
1Centre for Advanced Imaging, University of Queensland, Brisbane, QLD, Australia, ²Curtin University, Perth, WA, Australia, ³Prince of Wales Medical Research Institute, Sydney, NSW, Australia, ⁴Florey Neuroscience Institute, Parkville, VIC, Australia, ⁵Monash University, Clayton, VIC, Australia, ⁶Centre for Neuroscience, University of Melbourne, Parkville, VIC, Australia

In this study we developed 1) a detailed protocol for segmenting over 35 structures in the ex vivo C57BL/6J cerebellum on high-resolution MR images and 2) a probabilistic atlas of the C57BL/6J cerebellum.

Liqin Yang¹, Hao Wu¹, Fuchun Lin¹, and Hao Lei^1
1State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, China

Fluoxetine (FLX) is the most popular prescription drugs for treatment of major depressive disorder in young populations. Recent studies have shown that chronic exposure to Selective serotonin reuptake inhibitors (SSRI), such as FLX, during adolescence or juvenile may cause neuroplastic effects on some brain regions. In this work, we constructed tissue probability maps (TPMs) of adult rat brain using high resolution volumetric T2-weighted image datasets, and used them to perform VBM analysis on the structural changes caused by repeated FLX treatment in adolescent rats.

Andrew L Janke¹, Jeremy F P Ullmann², Nyoman D Kurniawan², George Paxinos³, Marianne D Keller², Zhengyi Yang², Kay Richards⁴, Gary F Egan⁵, Steve Petrou⁴, Graham J Galloway², and David C Reutens^2
1Center for Advanced Imaging, University of Queensland, Brisbane, Qld, Australia, ²Centre for Advanced Imaging, University of Queensland, Brisbane, QLD, Australia, ³Prince of Wales Medical Research Institute, Sydney, NSW, Australia, ⁴Florey Neuroscience Institute, Parkville, VIC, Australia, ⁵Monash University, Clayton, VIC, Australia

Super-resolution modelling techniques allow us to build 15um nonlinear average models from 30um 16.4T MRI data. We present 15um models from c57bl and R43Q epilepsy mice

Nicoleta Baxan¹, Iulius Dragonu¹, Laura-Adela Harsan¹, Juergen Hennig², and Dominik von Elverfeldt^3
1Department of Radiology, University Medical Center Freiburg, Freiburg, BW, Germany, ²Department of radiology, University Medical Center Freiburg, Freiburg, BW, Germany,³Department of Radiology, University Medical center Freiburg, Freiburg, BW, Germany

The signal phase information brought significant advantages in revealing anatomical details of the human brain yielding excellent depiction of cortical morphology and substructure. While cortical cytoarchitecture was extensively studied via histology, ex-vivo MRI or MEMRI, the detection of cytoarchitectural boundaries non-invasively was demonstrated in this study by exploiting the MR signal phase. We demonstrate for the first time the potential of phase images to solve the challenge of visualizing the cortical lamination of the living rat isocortex and mouse cerebellum. Frequency shifts occurring within and between WM/GM and cerebellar cortex were quantitatively analyzed at two field strengths, 7T and 9.4T.

Aline Seuwen¹, Daniel Marek², Stefan Zwick², Aileen Schröter¹, and Markus Rudin^1,3
1Institute for Biomedical Engineering, University and ETH, Zürich, Switzerland, ²Bruker BioSpin AG, Fällanden, Switzerland, ³Institute of pharmacology and toxicology, University of Zürich, Switzerland

First in vivo results of a four-element receive-only cryogenic phased array surface coil operating at 30K (2x2 geometry, overall coil size 20x27mm2) are presented. The coil system was used in combination with a room temperature volume resonator for transmission. FLASH and RARE sequences were applied for fast 2D and 3D high-resolution imaging. The phased array design allows accelerated data acquisition using parallel imaging strategies. Furthermore, the high sensitivity and uniform excitation enable whole brain imaging with high resolution. The setup is also attractive for functional MRI and spectroscopic imaging, which critically depend on high SNR values.

Mingming Huang¹, Lifeng Gao¹, Liqin Yang¹, and Hao Lei^1
1State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, Hubei, China

Type 1 diabetes was induced in rats by a single intraperitoneal injection of streptozotocin (STZ). High resolution brain anatomical images were acquired with a RARE sequence. And this study was performed on a 7T scanner to monitor the brain anatomical changes induced by diabetes. From the RARE imagings, voxel-based morphometry analyses using ¡®3 tissue classes¡¯ probability altas can detect subtle volume changes in gray and white matters in diabetic rats at 4w after STZ injections, with gray matter atrophy in cortex, amygdala (Amy), caudate putamen (Cpu), hippocampus (Hip), thalamus, periaqueductal gray matter (PAG), and white matter atrophy in cingulum (cg), corpus callosum (cc), external capsule (ec), internal capsule (ic), cerebral peduncle (cp), optic tract (opt), fimbria (fi).

Jurgen Germann¹, Armin Raznahan², Frank Probst³, and Jason P Lerch^1
1Mouse Imaging Centre, Sick Kids, Toronto, Ontario, Canada, ²Child Psychiatry, National Institute of Mental Health, Bethesda, MD, United States, ³Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States

Sex dimorphism and more general the role of sex chromosomes on brain development may provide crucial insight into neuropsychiatric disorders as nearly all of them have different ages of onset and gender bias in prevalence. Using the XO mouse model and whole brain high resolution imaging we found characteristic differences in brain morphology comparing mice with XO, XX< and XY genotypes providing an ideal model to investigate the role of sex chromosomes in brain development across various neurodevelopmental stages and genotypes.

Carsten Stueber¹, Markus Morawski², Miriam Waehnert¹, Katja Reimann¹, Nirav Barapatre³, Stefan Geyer¹, and Robert Turner^1
1Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ²Paul-Flechsig-Institute for Brain Research, University of Leipzig, Leipzig, Germany, ³LIPSION Laboratory, Institute of Nuclear Solid State Physics, University of Leipzig, Leipzig, Germany

Evidence suggests that myelin largely contributes to most types of MR image contrast (i.e. T₁-maps). However, the contribution of iron as an independent source of MR-tissue contrast remains poorly understood, due to the co-localization of myelin and iron in the cortex. We examed the role of iron-derived MR contrast in myelin- and iron-rich cortical areas of human cadaver brain tissue, using ion beam analysis to quantitavely map the iron concentration and comparing MRI of tissue blocks before and after removing iron. We could show that iron does play a significant role in brain tissue T₁ contrast.

Tina Jeon¹, Takashi Yoshioka², Austin Chen², Michael Miller³, Susumu Mori⁴, and Hao Huang^1,5
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States, ²Mind and Brain Institute, Johns Hopkins University, Baltimore, Maryland, United States, ³Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States, ⁴Department of Radiology, Johns Hopkins University, Baltimore, Maryland, United States, ⁵Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, United States

The neuroanatomical atlases play an essential role for brain-related research in multiple aspects, finding and identifying the unknown structures based on known ones, guiding the invasive operations, carrying the knowledge of brain structures for education and serving as registration references for mapping the functional information. An unsolved challenge of invasive neuroscientific experiment is to link the peripheral head landmarks to the targeted brain locations. In this study, we established a comprehensive high-resolution macaque DTI atlas uniquely characterized with both ex-vivo resolution and in-vivo space so that both brain anatomy details and head landmarks are included.

Bing Yao¹, Zhongming Liu¹, Peter van Gelderen¹, and Jeff H Duyn^1
1Advanced MRI Section, LFMI, NINDS, National Institutes of Health, Bethesda, MD, United States

Subcortical brain regions such as the basal ganglia and thalamus have important roles in brain function that may be compromised by many diseases. Their accurate localization is often challenging with clinical MRI contrast such as T1 and T2 that are optimized to distinguish the main tissue compartments of CSF, grey and white matter. Previous work has shown that magnetic susceptibility contrast (T2* weighted magnitude, R2*, and phase images) may provide additional contrast in subcortical regions. Here, we set out to generate a brain atlas aiming to distinguish the sub-regions in the subcortical areas that are not clearly visible in a conventional T1-based atlas.

Miriam Waehnert¹, Marcel Weiss¹, Pierre-Louis Bazin¹, Stefan Geyer¹, and Robert Turner^1
1neurophysics, Max-Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Saxony, Germany

Cortical profiling is an increasingly important tool in cortical parcellation and determination of cortical thickness. Profiles traversing the cortex have often been constructed numerically solving the Laplace equation to locate intracortical contours and thus the orthogonal profiles. It has been surmised that these profiles are relatively realistic or "natural". Can the Laplace equation solution adequately characterize the conformation of cortical layers as defined by cytoarchitecture or myeloarchitecture? With ultra-high resolution MR imaging, we have been able to answer this fundamental question by comparing the Laplace solution with the clearly defined Bands of Baillarger and the stria of Gennari.

Hui You¹, Yan-Ping Zhao², Han Wang³, Bo Hou², and Feng Feng^2
1Department of Radiology, Peking Union Medical College Hospital, Beijing, Beijing, China, ²Department of Radiology, Peking Union Medical College Hospital, ³Department of Neurology, Peking Union Medical College Hospital

The aim of this study is to assess the brain metabolic changes in patients with parkinsonian multiple system atrophy (MSA-P) parkinson¡¯s disease (PD). The subjects, including 45 controls, 27 PD and 40 clinically probable MSA-P patients, underwent MR spectroscopy in pons, basal ganglia and motor cortex. Our results suggest creatine concentration in MSA-P is not stable as presumed previously. Absolute concentration demonstrates metabolite changes more intuitively than concentration ratios. According to changes of individual metabolite, more sensitive concentration ratios may be defined. The metabolite concentration changes, especially in pons, may be valuable for differential diagnosis of MSA-P and PD.

Caroline Rae¹, Clarence Chiang¹, Gabrielle Todd², Michael Hayes³, and Kay Double^1
1Neuroscience Research Australia, UNSW, Randwick, NSW, Australia, ²The University of South Australia, Adelaide, Australia, ³Concord Repatriation Hospital, The University of Sydney, Australia

Evidence suggests that Parkinson’s disease-associated neuronal dysfunction occurs years before symptoms appear and clinical diagnosis is possible. Compensatory changes in brain motor circuitry, including increased activation or novel area recruitment may help to mask symptom development. We studied the pre-supplementary motor area in persons with PD, those at increased risk, and normal controls using short-echo PRESS at 3T. We found significantly increased glutamate in PD and strong correlations between glu/NAA and Glu/Cre with a score of motor deficits, the UPDRS. We suggest that increased preSMA activity may predate decreased NAA but whether this is a compensatory mechanism awaits further investigation.

Xiaojun Xu¹, Dan Long¹, and Minming Zhang^1
1Department of Radiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China

Patients with Parkinson's disease (PD) have difficulty in performing self-initiated movements. Although the relationship between the dysfunction of SMA and the defect of self-initiated movements in PD patients has been well established, little has been known about how the dysfunction of SMA affected the whole functional network during movement. In this study, using fMRI and complex network analysis based on graph theory, we demonstrated the topological changes of the brain networks during performance of self-initiated movement in PD patients.

Kimihiro Ogisu¹, Kosuke Kudo², Makoto Sasaki², Ken Sakushima³, Satoshi Terae⁴, Mitsuhiro Nakanishi⁵, Shunrou Fujiwara⁶, and Hiroki Shirato^1
1Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido, Japan, ²Advanced Medical Research Center, Iwate Medical University, ³Department of Neurology, Hokkaido University Hospital, ⁴Department of Radiology, Hokkaido University Hospital, ⁵Hokkaido University Hospital, ⁶Department of Neurosurgery, Iwate Medical University

Neuromelanin-sensitive MRI has been reported for the diagnosis of Parkinson's disease (PD). However, previous reports used 2D fast spin echo sequence with subjective measurement of the substantia nigra pars compacta (SNc). We developed 3D gradient echo technique of neuromelanin-sensitive MRI. The volume of SNc was automatically measured and was significantly smaller in PD patients than in healthy volunteers. Although sensitivity and specificity were not high enough compared to the previous reports, 3D neuromelanin-sensitive MRI with automated volume measurement was feasible, and could objectively distinguish PD patients from healthy volunteers.

Jill M Slade¹, Robert McClowry¹, Deborah Gelinlas^2,3, Theodore F Towse⁴, and Ronald A Meyer^5
1Radiology, Michigan State University, East Lansing, MI, United States, ²Neurology, Michigan State University, ³ALS Clinic, St. Mary Freebed Rehabilitation Hospital, Grand Rapids, MI, ⁴Radiology, Vanderbilt University, Nashville, TN, ⁵Physiology, Michigan State University, East Lansing, MI

ALS is a progressive motor neuron disease that results in rapid motor neuron loss. Early in disease progression, patients undergo reinnervation from healthy motor nerves and muscle quantity and function can be preserved. Muscle T2 of the leg muscles was used to evaluate the neuromuscular reorganization in patients with ALS by examining T2 heterogeneity. The main study outcome suggests that neuromuscular organization is not altered with ALS. The study revealed a sub-population of patients with elevated resting muscle T2 and altered muscle responses to dynamic exercise.

Paola Valsasina¹, Federica Agosta¹, Nilo Riva², Massimiliano Copetti³, Michele Perini⁴, Alessandro Prelle⁵, Domenico Caputo⁶, Fabrizio Salvi⁷, Maria Josè Messina², Giancarlo Comi², and Massimo Filippi^1
1Neuroimaging Research Unit, Institute of Experimental Neurology, San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Milan, Italy, Italy, ²Department of Neurology, San Raffaele Scientific Institute and Vita-Salute San Raffaele University, Milan, Italy, Italy, ³Biostatistics Unit, IRCCS-Ospedale Casa Sollievo della Sofferenza, San Giovanni Rotondo, Italy, ⁴Department of Neurology, Ospedale di Gallarate, Gallarate, Italy, ⁵Neurologic Unit, Azienda Ospedaliera Fatebenefratelli e Oftalmico, Milan, Italy,⁶Department of Neurology, Scientific Institute Fondazione Don Gnocchi, Milan, Italy, ⁷Department of Neurology, Ospedale di Bellaria, Bologna, Italy

In this study, we explored differences of regional cortical thickness (CT) between a large group of patients with amyotrophic lateral sclerosis (ALS) and matched healthy controls. We also assessed whether cortical thinning in these patients is associated with clinical variables. Results indicated a significant bilateral thinning of sensorimotor, frontal, insular, temporal, parietal and occipital cortices. Mean CT of the sensorimotor, frontal and temporal cortices was able to distinguish patients with ALS from healthy controls. Decreased CT in sensorimotor regions was more strongly associated with age in ALS patients than in controls, and it was correlated with disease progression rate.

Varan Govind¹, Khema Sharma², Andrew A Maudsley¹, Kristopher L Arheart³, Gaurav Saigal¹, and Sulaiman Sheriff^1
1Radiology, University of Miami, Miami, Florida, United States, ²Neurology, University of Miami, ³Epidemiology and Public Health, University of Miami

In previous studies, proton MR-observed brain metabolite data analysis in the primary motor cortex and corticospinal tract was performed using manually drawn regions-of-interest (ROIs). Such an approach is bound to have subjectivity introduced by the manual selection of ROIs. In this study, a comprehensive analysis of brain metabolite [N-acetyl aspartate (NAA), total-creatine (Cre) and total-choline (Cho)] alterations in the CST of subjects with ALS was performed using a 3D CST atlas.

Franklyn Arron Howe¹, Nidhi Sofat², and Thomas Richard Barrick^1
1Clinical Sciences, St George's, University of London, London, United Kingdom, ²Biomedical Sciences, St George's, University of London, London, United Kingdom

Metabolite levels were quantified by 1H MRS in parietal and frontal brain regions of lupus patients and correlated with fractional anisotropy (FA) and median diffusivity determined by Diffusion Tensor Imaging in the same voxels. We investigated whether: a) neuronal damage represented by reductions in FA would correlate with reduced NAA; b) inflammatory processes would lead to a correlation of increased mI with ESR; c) global disease processes occur that lead to correlation of metabolite changes in frontal and parietal regions.

Monika Dezortova¹, Vit Herynek¹, Martin Krssak², Claudia Kronnerwetter³, and Milan Hajek^1
1MR-Unit, Institute for Clinical and Experimental Medicine, Prague, Czech Republic, ²Division of Endocrinology & Metabolism, Dept. Internal Medicine III, Medical University Vienna, Vienna, Austria, ³Dept. Radiology, Medical University Vienna, Vienna, Austria

We estimated iron concentration in the globus pallidus (GP) in PKAN patients using quantitative relaxometry at different field strengths. T2 values in GP in three PKAN patients and five controls were studied as well as phantoms containing ferritin and SPIO nanoparticles. The iron content in GP of our PKAN patients was estimated as 391ƒÝg/ml in the ferritin plus 1.1ƒÝg/ml superparamagnetic iron form compared to 178ƒÝg/ml in the only ferritin in controls. Our data suggest that MRI findings in PKAN patients are not simply proportional to increasing iron concentration but can be explained by small amount of iron in superparamagnetic form.

Yi Zhang^1,2, Oscar San Emeterio Nateras¹, Joseph M Harrison³, Qi Peng¹, and Timothy Duong^1,2
1Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, ²Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, ³Ophthalmology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States

Altered ocular blood circulation and metabolic environment have been implicated in the degenerative process and/or the pathogenesis of retinitis pigmentosa (RP), yet the lack of non-invasive imaging techniques have limited the investigation and full understanding of such mechanism. This study presents an innovative MRI approach to study blood flow and BOLD functional MRI responses of hyperoxia in retinas of RP patients. MRI findings were discussed and compared with clinical eye exams. With improvement in spatiotemporal resolution and sensitivity, MRI has the potential to provide unique, depth-resolved information on blood flow, oxygenation and function changes in RP and other retinal diseases.

Nathalie Doorenweerd^1,2, Chiara S.M. Straathof³, Erik Niks³, Andrew Webb¹, Mark A. van Buchem¹, Jan J.G.M. Verschuuren³, and Hermien E. Kan^1
1Radiology, Leiden University Medical Centre, Leiden, Zuid-Holland, Netherlands, ²Neurology, Leiden Univeristy Medical Centre, Leiden, Zuid-Holland, Netherlands, ³Neurology, Leiden University Medical Centre, Leiden, Zuid-Holland, Netherlands

Brain and skull morphology were studied in DMD boys and healthy age matched controls using T1w images, and tape-measured head circumference. MRI results showed a significant increase in eccentricity and temporalis muscle hypertrophy in DMD compared with controls, whereas tape-measured head circumference did not differ between groups. In addition, a trend was found in decreased skull circumference in DMD. Further investigation of these findings is needed to determine their effect on skull circumference measurements at young age, their use in explaining dental or feeding problems or how they could even aid clinical screening for the diagnosis of DMD.

Ai-Ling Lin¹, Shao-Hua Yang², Fang Du¹, Andrew Bresnen¹, Shiliang Huang¹, and Timothy Q Duong^1
1Research Imaging Institute, University of Texas Health Science Center at San Anotnio, San Antonio, TX, United States, ², Institute for Alzheimer’s Disease and Aging Research, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX, United States

Methylene blue (MB) can sustains ATP production by acting as an electron donor in the mitochondrial electron transport chain under stressed condition. MB is clinically used to treat methemoglobinemia and cyanide poisoning, and it has recently been shown to be neuroprotective in a number of neurological diseases. We recently showed that MB increased cerebral blood flow, cerebral metabolic rate of oxygen, and cerebral metabolic rate of glucose in rat brains, with corroboration by in vitro measures of glucose and oxygen consumption. In this study, we asked the question whether MB could help sustain hemodynamic and metabolic responses under hypoxic conditions.

Ai-Ling Lin¹, Ethan Poteet², Fang Du¹, Andrew Bresnen¹, Shiliang Huang¹, Yi Wen², Shao-Hua Yang², and Timothy Q Duong^1
1Research Imaging Institute, University of Texas Health Science Center at San Anotnio, San Antonio, TX, United States, ², Institute for Alzheimer’s Disease and Aging Research, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX, United States

Methylene blue (MB) helps to sustain ATP production by acting as an electron donor in the mitochondrial electron transport chain. MB has long been used to treat methemoglobinemia and it has recently been shown to have neuroprotective in a number of neurological diseases. This study evaluated the metabolic and hemodynamic effects of MB in vivo. Cerebral metabolic rate of oxygen cerebral metabolic rate of glucose, oxygen extraction fraction and cerebral blood flow were measured in those conditions in rats. Comparisons were made with in vitro studies that measured glucose and oxygen consumption.

H. Prinsen¹, H. W.M. van Laarhoven¹, G. Bleijenberg², M. J. Zwarts³, M. van der Graaf^4,5, M. Rijpkema⁶, and A. Heerschap^4
1Medical Oncology, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands, ²Expert Centre Chronic Fatigue, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands, ³Clinical Neurophysiology, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands, ⁴Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands, ⁵Clinical Physics Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands, ⁶Nuclear Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands

Until now, little is known about (neuro)physiological factors determining postcancer fatigue, which is a frequently occurring problem, impairing quality of life. The brainstem seems to be an important link in the pathogenesis of fatigue in general and may also be of importance for postcancer fatigue. Therefore, it was investigated if brainstem volume of fatigued cancer survivors is influenced by cognitive behavior therapy. The change in brainstem volume from baseline to follow-up was significantly larger in the therapy condition compared to the waiting list condition. These findings suggest that the brainstem plays a central role in the pathophysiology of postcancer fatigue.

Yu Sub Sung¹, Seonjoo Kwon¹, Woo Hyun Shim¹, Gyunggoo Cho², Hyungjoon Cho³, Jeong Kon Kim^1,4, Bruce Rosen¹, and Young Ro Kim^1
1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States, ²Korea Basic Science Institute, ³Ulsan National Institute of Science and Technology, ⁴Asan Medical Center, University of Ulsan

Accurate determination of T1 values in the brain is clinically important for assessing various neurological diseases and also for the successful execution of perfusion and dynamic contrast agent studies. In this work, we propose a clinically practical T1measurement method using the widely available 3D gradient echo sequence and the optimized acquisition strategy with mixed FA and TR for efficiently and accurately calculating T1 maps in the brain. This new combination method is an attractive alternative to other conventional methods, providing accurate T1 measurements in a reasonable scan time.

Gunther Helms¹, Peter Dechent¹, and Melanie Wilke^1
1Dept. Cognitive Neurology, MR-Research in Neurology and Psychiatry, University Medical Center, Göttingen, Germany

In order to identify thalamic nuclei not visible by MRI due small size and/or poor contrast, the population-based Morel atlas was registered to the 0.5mm MNI brain template, converting vtk meshes to nifti. Affine transformations were determined for each hemisphere by iterative manual assignment of anatomical landmarks. The MNI template is angulated by ~7 degrees against the intercommissural line. Small residual deviations were found around the anterior and posterior pole. The atlas is used to assign nuclear territories to thalamic stroke lesions after non-linear registration of structural MRI to MNI space.

Peng Sun¹, Yong Wang¹, Ying-Jr Chen², Anne Cross³, and Sheng-Kwei Song^1
1Radiology, Washington University in St. Louis, Saint Louis, MO, United States, ²Chemistry, Washington University in St. Louis, Saint Louis, MO, United States, ³Neurology, Washington University in St. Louis, Saint Louis, MO, United States

DTI has been demonstrated to reflect the optic nerve axonal and myelin damage and predict function in optic neuritis patients. However, inflammation associated cell infiltration and vasogenic edema confounds DTI findings. In the present study, a newly developed diffusion basis spectrum imaging (DBSI) was employed to resolve the complex pathologies in optic nerves from experimental autoimmune encephalomyelitis (EAE) mice. The Carr-Purcell-Meiboom-Gill (CPMG)-T2 was also employed to estimate the extent of demyelination by measuring myelin water fraction (MWF) of the nerve. The current results suggest that DBSI may be used to identify and quantitate demyelination, as well as inflammation-related vasogenic edema. DBSI holds promise to resolve inflammation and edema, factors which have confounded DTI interpretation.

Jiabao He¹, Kieren G Hollingsworth¹, Julia L Newton², and Andrew M Blamire^1
1Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom, ²Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom

Chronic Fatigue Syndrome (CFS) is related to a compromised skeletal muscle response to exercise and autonomic dysfunction. We hypothesised that if CFS has a central mediating factor then there would be a correlation between the pH handling in skeletal muscle and cerebral vascular regulation. We performed ASL MRI to measure CBF and 31P MRS to probe skeletal muscle pH at rest. We conducted fMRI concurrently with the Valsalva manoeuvre, as well as 31P MRS to measure recovered pH after plantar flexion exercise. We found there is a close relationship between skeletal muscle pH and cerebral vascular regulation in CFS.

Hojjatollah Azadbakht^1,2, Laura M Parkes^1,2, Hamied A Haroon^1,2, Mark Augarth³, Nikos K Logothetis³, Alex de Crespigny⁴, Helen E D’Arceuil⁴, and Geoffrey J M Parker^1,2
1Imaging Science and Biomedical Engineering, School of Cancer and Imaging Sciences, University of Manchester, Manchester, United Kingdom, ²The Biomedical Imaging Institute, University of Manchester, Manchester, United Kingdom, ³Max Planck Institute for Biological Cybernetics, Tubingen, Germany, ⁴Athinoula A. Martinos Center, MGH, Charlestown, MA, United States

Validation of diffusion imaging has proved difficult due to the lack of an adequate gold-standard. In this work, the macaque visual system is used as a model, in which due to an extensive literature of in-vivo and post-mortem tracer studies, “true” connections are well-established. We performed probabilistic tractography on diffusion imaging data from two in-vitro macaque brains, and comparisons were made between identified connections at different thresholds of connection strength, and connections identified in the visual system wiring map of Felleman & van Essen. The effects of streamline-length based correction of the distance bias of probabilistic tractography were also explored.

Tynan Reid Stevens¹, Ryan CN D'Arcy¹, Steven D Beyea¹, and David B Clarke^2
1IBD-Atlantic, NRC, Halifax, Nova Scotia, Canada, ²QEII Health Science Centre, Halifax, Nova Scotia, Canada

Localization of cortical stimulation (CS) measurements on MR images is subject to error from brain shift at time of dural opening. We present a method for using digitized CS points and a cortical surface mask extracted from a high-resolution MRI to compute first order corrections for brain shift. CS measurements were recorded for nine brain tumor patients using a neuronavigation system. An iterative-closest-point algorithm was developed to minimize the distance between the CS points and the MR-extracted cortical surface. The mean distance between the CS points and brain surface was reduced from 3.8 +/- 0.5 to 1.6 +/- 0.3 mm.

Burkhard Mädler¹, and Jürgen Gieseke^2,3
1Neurosurgery, University Bonn, Bonn, NRW, Germany, ²Philips Healthcare, Best, Netherlands, ³Radiology, University Bonn, Bonn, Germany

Validation of quantitative multi-component relaxation methods remains a challenge for the lack of suitable phantoms with known parameters. We re-facilitate the use of a fat-water phantom that uses dairy cream to validate and address the accuracy of multi-exponential analysis techniques (data acquisition and analysis). The problem of different proton densities of milk fat and water was previously not taken into consideration. Depending on the dairy cream's fat composition, primarily their content of triacylglycerides (98% of milk fat), the error in the fractional estimates can easily exceed 10-20%. We suggest an easy correction method based on partial proton densities for fat and water.

Napapon Sailasuta¹, William Ross², Jintanat Ananworanich^3,4, Thep Chalermchai⁵, Victor DeGrutolla⁶, Sukalaya Lerdlum⁴, Mantana Pothisri⁴, Edgar Busovaca⁷, Serena Spudich⁸, Nelson Michael⁹, Jerome H Kim⁹, Victor Valcour⁷, and On behalf of RV254/SEARCH010 Protocol Teams^3
1HMRI, Pasadena, CA, United States, ²Tufts University, Medford, MA, ³SEARCH -Thailand, Bangkok, Thailand, ⁴Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand, ⁵SEARCH-Thailand, ⁶Department of Epidemiology and Biostatistics, Harvard School of Public Health, Boston, MA, ⁷Department of Medicine, University of California, San Francisco, CA, ⁸Department of Neurology, Yale University, Boston, MA, ⁹US Military HIV Research Program, Rockville, Maryland

We described findings of neuronal dysfunction in acute HIV infection as early as 14 days after virus exposure.

Maged Goubran^1,2, Terry M. Peters^1,2, and Ali R. Khan^1
1Robarts Research Institute, London, Ontario, Canada, ²Biomedical Engineering, University of Western Ontario, London, Ontario, Canada

The identification of cellular abnormalities in histology of the resected tissue has the potential to validate the effectiveness of multi-spectral magnetic resonance imaging (MRI) in pre-operative foci localization in temporal lobe epilepsy. We investigated the correlation between ex-vivo MR images and neuronal cell density of hippocampal sub-fields from histological slides. Segmented cell counts of hippocampal sub-fields were consistent with pathological findings as well as local entropy values of MR images. We have shown that ex-vivo MR images have the potential to differentiate between the hippocampal sub-fields through local features and entropy measurements.

Matthew A Howard¹, Jonathan O'Muircheartaigh², Kristina Krause¹, Nathalie Massat³, Nadine Khawaja¹, John P Huggins⁴, William Vennart⁴, Tara F Renton⁵, Andre Marquand¹, and Steven C R Williams^1
1Neuroimaging, King's College London, Institute of Psychiatry, Camberwell, London, United Kingdom, ²Clinical Neuroscience, King's College London, Institute of Psychiatry, United Kingdom, ³Centre for Cancer Prevention, Queen Mary University Of London, ⁴Pfizer Global Research and Development, ⁵Dental Institute, King's College London, United Kingdom

Recent reports have described the application of arterial spin labelling (ASL), to interrogate perfusion changes associated with the central representation of ongoing pain. We used Gaussian Process Classification, a supervised 'machine learning' multivariate analysis technique, to provide probabilistic classification of 'No Pain' from 'Ongoing Pain' states, as experienced following wisdom tooth extraction, using only ASL-derived indices of regional cerebral blood flow (rCBF) in each state. GPC classified between states with accuracy above 90%; 80% accuracy could be maintained using only two rCBF maps per state. This methodology has potential to impact on efficient economic assessment of novel treatments for pain.

Yi Zhang¹, Oscar San Emeterio Nateras¹, Qi Peng¹, Joseph M Harrison², and Timothy Duong^1,2
1Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, ²Ophthalmology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States

MRI of the human retina is challenging due to its thin structure requires high spatial resolution, and eye movement in unanesthetized humans may cause considerable motion artifacts. This study first demonstrated the adequate eye fixation stability using cued blinks as evaluated by an independent eye tracker. It also reported the feasibility of using high-resolution MRI to delineate the laminar structure of the human retina at 3T. MRI layer assignments were corroborated by using contrast-enhanced MRI which selectively enhanced the vascularized boundaries of the retina. This study encourages further investigation of depth-resolved retinal MRI and its applications in retinal diseases.