R Stephen Nicholas^1,2, Stephen J Gandy^1,2, and J Graeme Houston^3,4
1Medical Physics, NHS Tayside, Dundee, Angus, United Kingdom, ²Medical Physics, University of Dundee, Dundee, Angus, United Kingdom, ³Radiology, NHS Tayside, Dundee, Angus, United Kingdom, ⁴Clinical Imaging, University of Dundee, Dundee, Angus, United Kingdom

This work characterised an Inversion Recovery prepared SSFP used for determining the optimum Inversion Time (TI) in the myocardium after contrast administration. Gel phantoms with known T1 and T2 values were scanned with different simulated heart rates to measure the variation in the optimum TI. The results showed that there is considerable variation in TI. These results were applied in a small cohort of patients to account for heart rate variability in T1 measurements for both pre-and post-contrast TI measurements in normal and hyper-enhanced myocardium. However, significant variability was still observed, particularly in the pre-contrast measurements.

Yasuo Amano¹, Masaki Tachi¹, Yoshiaki Komori², Yuriko Suzuki², Tetsuro Sekine¹, and Shinichiro Kumita^1
1Nippon Medical School, Tokyo, Tokyo, Japan, ²Philips Electronics Japan, Tokyo, Japan

Postcontrast 2D Look-Locker MRI is able to detect the diffuse myocardial fibrosis, but covers only one slice. 3D Look-Locker MRI may permit the estimate of postcontrast T1-values of the whole left ventricular myocardium in the 4-chamber view during a single breath-hold, comparable to 2D Look-Locker MRI.

Kai Jiang^1,2, and Xin Yu^1,2
1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States, ²Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, United States

An ECG-triggered multi-slice saturation-recovery Look-Locker (MSRLL) method was developed for fast cardiac T1 mapping. High temporal resolution (2.5 minutes) was achieved without the aid of parallel imaging or EPI. Phantom and in vivo validations were performed by comparing measured T1 with that using the single-slice Look-Locker method.

Brian R Watson¹, and Edward W Hsu^1
1Bioengineering, University of Utah, Salt Lake City, Utah, United States

Contrary to some tissues, little is known regarding the effects of fixation on Diffusion Tensor Imaging of cardiac specimens. Our goal was to systematically assess the effects of fixation, including factors such as specimen preparation, time of fixation, fixation duration, and fixative type, on DTI derived parameters measured in myocardial specimens. Utilizing canine hearts, we found that unfixed tissues lose fractional anisotropy(FA) and mean diffusivity(MD) over time. Also, we significantly show that fixed myocardium lost FA and MD due to fixation. In contrast, KCl did not significantly effect FA. These results help provide guidelines for future cardiac studies.

Adrianus J. Bakermans¹, Bastiaan J. van Nierop¹, Desiree Abdurrachim¹, Klaas Nicolay¹, and Jeanine J. Prompers^1
1Biomedical NMR, Eindhoven University of Technology, Eindhoven, Netherlands

3D Image-Selected In vivo Spectroscopy (ISIS) for non-invasive cardiac ³¹P-MRS was used to investigate the myocardial energy status in a thoracic aortic constriction (TAC) mouse model of heart failure. By maintaining a constant TR, signal contamination from tissue surrounding the heart was minimized. Left ventricular function and morphology were assessed using cine MRI. Decreased ejection fraction and increased myocardial mass were accompanied by a decreased phosphocreatine to ATP ratio in TAC mice, indicating a disturbed energy homeostasis. This non-invasive approach will be useful to investigate cardiac disease progression and the effects of therapeutic strategies in longitudinal study designs.

Vijayasarathi Nagarajan¹, Philip William Kuchel¹, and S. Sendhil Velan^1
1Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Singapore, Singapore, Singapore

We evaluated the myocardial fat content in rats fed with a placebo and a high fat diet. We demonstrated the presence of two lipid pools in the myocardium of the rats with obesity induced by high fat diet. The left ventricular function was significantly reduced in rats fed with high fat diet. The concentration of IMCL in myocardium may be a potential marker for early stages of diabetes.

Paul Jaegu Kim¹, Ildiko Toma¹, Phillip Harnish², and Phillip Yang^1
1Cardiovascular Medicine, Stanford University, Stanford, CA, United States, ²Eagle Vision Pharmaceutical

To date, the underlying mechanism responsible for the restoration of the injured myocardium following transplantation of stem cells has not been clearly identified. Manganese-enhanced MRI (MEMRI) has recently been published as a reliable method of imaging viable myocardium. Utilizing MEMRI, we evaluated the changes in the viability of the injured myocardium to further investigate the underlying mechanism of functional restoration using stem cell therapy. A more sensitive measurement of myocardial restoration is significantly increased MEMRI signal observed in the ESC-RGs vs. control mice (119+.005 cm3 vs .0736+.001 cm3 respectively, p=0.034), indicating improved myocardial viability. Thus, MEMRI shows a significant increase in viable myocardium in ESC-RG transplanted hearts, indicating myocardial restoration.

Hyeyoung Moon^1,2, Hyo Eun Park³, Jongeun Kang^1,4, Kiyuk Chang³, and Kwan Soo Hong^1,4
1Division of MR research, Korea Basic Science Institute, Cheongwon-Gun, Chungcheongbuk-Do, Korea, Republic of, ²Bio-Analytical Science, University of Science and Technology, Daejeon, Korea, Republic of, ³Department of Internal Medicine, Catholic University, Seoul, Korea, Republic of, ⁴Graduate School of Analytical science and Technology, Chungnam National University, Daejeon, Korea, Republic of

In this study, we investigated whether PEGylated fluorescent magnetic nanoparticles (MNP) could detect the inflammatory areas in experimentally induced autoimmune myocarditis (EAM) rats with in vivo cardiac MRI. In addition, we examined the MNP¡¯s possibility if we apply to clinical research by exploring the inflammatory dilation and therapeutic effect.

Maythem Saeed¹, Sammir Sullivan¹, Loi Do¹, and Mark Wilson^1
1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, Ca, United States

The objectives were to use DE-MRI and DE-MDCT imaging and light microscopy to determine the relationship and the limits of agreement for measuring myocardial microinfarct. Pigs (n=14) received either 16mm³ or 32mm³ of 40-120µm microemboli. Clinical MRI and MDCT scanners were used 3 days after microembolization. Gd-DTPA and iohexol were used to enhance microinfarct. MRI and MDCT imaging showed systematic underestimation of microinfarct size and area at risk compared with histopathology, which should be considered in evaluating microinfarct using these modalities and may be related to differences in spatial resolution, light microscopy, mismatch between slices and volume averaging effect.

Edvin Johansson¹, Johan Jirholt², Katja Madeyski-Bengtson², and Paul D Hockings^1
1PHB Imaging, AstraZeneca R&D Molndal, Molndal, Sweden, ²DS Bioreagents, AstraZeneca R&D Molndal, Sweden

A transgenic mice model of cardiomyocyte-specific acyl CoA synthase overexpression, inducible in mature mice and believed to cause myocardial steatosis was investigated. In vivo triglyceride quantification was performed via MRS and validated against analytical chemistry. The agreement between the two techniques was good, and both techniques demonstrated increased myocardial triglyceride levels in ACS overexpressing mice when compared to unmodified mice. The ejection fraction was markedly reduced in ACS overexpressing mice, but this finding requires further investigations in order to rule out factors associated with the transgenic modification, but not directly related to the accumulation of myocardial triglycerides.

Anders Frodo Stegmann¹, Esben Søvsø Szocska Hansen¹, W. Yong Kim^1,2, and Samuel Alberg Thrysøe^1
1MR-Research Centre, Aarhus University Hospital, Skejby, Aarhus N, Denmark, ²Dept. of Cardiology, Aarhus University Hospital, Skejby, Aarhus N, Denmark

 

Yasuo Amano¹, Yoshiaki Komori², Masaki Tachi¹, Hitomi Tani¹, Tetsuro Sekine¹, and van Cauteren Marc^2
1Nippon Medical School, Tokyo, Tokyo, Japan, ²Philips Electronics Japan, Tokyo, Japan

Gradient- and spin-echo imaging (GRASE) with the multishot acquisition = 3, 5, 7 was performed to generate T2-mapping and to measure myocardial T2-value in a single-breath-hold. ECG-gating, black-blood preparation and 5-multiecho-time acquisition (i.e., 20, 30, 40, 50, and 60 ms) were applied to both SE and GRASE. The GRASE with the multishot acquisition = 3 provided the T2-mapping with few artifacts and the myocardial T2-values comparable to those acquired by SE imaging during the acceptable breath-holding time. The interventricular septal myocardium may be appropriate for the T2-value measurement.

Donnie Cameron¹, David Higgins², Baljit Jagpal¹, Margaret Bruce¹, Nishat Siddiqi¹, Christian Stehning³, Michael Frenneaux¹, Thomas Redpath¹, and Dana Dawson^1
1The University of Aberdeen, Aberdeen, Scotland, United Kingdom, ²Philips Healthcare, Guildford, United Kingdom, ³Philips Research, Hamburg, Germany

Modified Look-Locker Inversion recovery (MOLLI) is a useful tool for measuring T₁ values in the myocardium. We applied MOLLI to acute myocardial infarction and acute tako-tsubo cardiomyopathy in order to assess its ability to distinguish normal myocardium from abnormal myocardium. Comparing two patient groups with healthy volunteers, MOLLI showed significant differences in T₁ values of infarcted segments as compared to normal segments(p<0.005). Tako-tsubo dyskinetic segments demonstrated significantly higher T₁ values than both normal and infarcted myocardium (p<<0.0001 versus normal). These results show that MOLLI sensitively delineates abnormal myocardium and provides superior evaluation compared to T₂-weighted assessment.

Wessel P Brouwer¹, Emma Baars¹, Tjeerd Germans¹, Karin de Boer¹, Aernout M Beek¹, Jolanda van der Velden², Arthur AM Wilde³, Albert C van Rossum¹, and Mark BM Hofman^4
1Cardiology, ICaR-VU, VU University Medical Center, Amsterdam, Netherlands, ²Physiology, ICaR-VU, VU University Medical Center, ³Cardiology, Academic Medical Center, Amsterdam, Netherlands, ⁴Physics and Medical Technology, ICaR-VU, VU University Medical Center, Amsterdam, Netherlands

Autopsy studies revealed areas of interstitial fibrosis in hypertrophic cardiomyopathy (HCM), but current late gadolinium enhancement imaging (LGE) is unable to depict diffuse deposition of collagen fibers. Therefore, we used T1 mapping with a Modified Look-Locker Inversion Recovery (MOLLI) pulse sequence to determine the distribution volume (Vdm) for extracellular Gd-DTPA in non enhanced myocardium, which is a measure of interstitial fibrosis. Results showed that LGE positive HCM patients have significantly higher (Vdm) values then LGE negative HCM patients and controls. Besides, pre-hypertrophic HCM mutation carriers had higher (Vdm) then controls, suggesting that interstitial fibrosis occurs early in the disease process.

Jan Weis¹, Morten Bruvold², Francisco Ortiz-Nieto¹, and Håkan Ahlström^1
1Department of Radiology, Uppsala University Hospital, Uppsala, Sweden, ²Philips Healthcare, Best, Netherlands

Cardiac and respiratory triggered 2D PRESS echo-planar spectroscopic imaging with high spatial resolution was used for the assessment of triglyceride content in the human myocardium. The PRESS volume of interest selection enables smaller field of view and minimizes signal contamination from outside the PRESS box. The proposed data processing approach using magnitude spectra avoids the need for individual phase correction before voxel spectra averaging. High spatial resolution enables evaluation the local triglyceride changes in non-continuous and irregularly shaped volumes of interest.

Lowell Chang¹, Divya Verma¹, Eugene Kholmovski², Sathya Vijayakumar², Nathan Burgon², Nassir Marrouche¹, and Christopher McGann^1
1Cardiology, University of Utah School of Medicine, Salt Lake City, UT, United States, ²Utah Center for Advanced Imaging Research, University of Utah School of Medicine, Salt Lake City, UT, United States

Serial cardiac MRI is a useful tool in the characterization of injury of pulmonary veins leading to pulmonary vein stenosis after radiofrequency ablation for atrial fibrillation. Acute edema/inflammation immediate post-ablation can be seen by T2-weighted imaging, while late gadolinium-enhanced imaging show remodeling leading to scar. Pulmonary vein stenosis is best predicted by MRA measurements of baseline pulmonary vein caliber and immediate post-ablation pulmonary vein narrowing.

Aya Kino¹, Darshit Thakrar², Rahul Rustogi², Brandon Benefield³, Jeremy D Collins², Daniel Lee², Lubna Choudhury⁴, and James C Carr^2
1Radiology, Northwestern University, Chicago, IL, United States, ²Radiology, Northwestern University, ³Medicine Cardiology Division, Northwestern, ⁴Medicine Cardiology Division, Northwestern University

The purpose of the study is to demonstrate the HCM patient present higher myocardial extravascular extracellular volume fraction in scar/ fibrosis areas obtained by using a single-shot modified Look Locker inversion recovery sequence (MOLLI) with balanced SSFP MR Sequence.

Valeriy Tkachenko¹, Florian von Knobelsdorff-Brenkenhoff¹, Denise Kleindienst¹, Lukas Winter², Jan Rieger², Tobias Frauenrath², Matthias A. Dieringer², Davide Santoro², Thoralf Niendorf^1,2, and Jeanette Schulz-Menger^1
1WG Cardiac MRI at ECRC Medical University Berlin, Charité Campus Buch, Berlin, Germany, ²Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine, Berlin, Germany

The assessment of the right ventricle (RV) is a challenge in today's cardiology. CMR at 1.5T is the accepted gold standard for RV quantification. The higher spatial resolution achievable at ultrahigh field strength (UHF) offers the potential to gain new insights into the structure and function of the RV. To approach this goal accurate RV chamber quantification at 7T has to be proven. Consequently this study examines the feasibility of assessment of RV dimensions and function at 7T using improved spatial resolution enabled by the intrinsic sensitivity gain of UHF CMR.

Iacopo Carbone¹, Bahare Saidi¹, Manuela Mariyadas², Ilaria Iampieri³, Marco Francone³, and Matthias Friedrich^1
1CMR Centre, Montreal Heart Institute, Montreal, Quebec, Canada, ²Department of Internal Medicine II, University of Ulm, Ulm, Germany, ³Department of Radiological, Oncological and Pathological Sciences, "Sapienza", University of Rome, Rome, Italy, Italy

In late-reperfused acute myocardial infarction (AMI) there is always a difference between the area at risk (measured with T2-weighted images) and infarct area (measured with late gadolinium enhancement). 41 patients with with late reperfused (>8hours) AMI were enrolled in the study. The mean difference between AAR and IA after 8hours was 9±7.25% and did not significantly increased over time. These data indicate that in late-reperfused MI, the edema surrounding infarcted tissue likely represents reversible tissue injury not related to myocardial salvage. These findings have significant implications for the quantification of myocardial salvage by CMR in patients with late refused MI.

Tobias Wech¹, Victoria Thornton², Craig A. Lygate², Stefan Neubauer², Herbert Köstler¹, and Jürgen E. Schneider^2
1Institute of Radiology, University of Würzburg, Würzburg, Germany, ²Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom

Parallel Imaging (PI) and Compressed Sensing (CS) have been shown to individually provide a three-fold reduction in scan-time for cine MRI in mice whilst providing accurate measurement of the physiologically relevant parameters. We now sought to combine PI and CS to further accelerate cine-MRI in mouse hearts at 9.4T. Fully acquired cine-data sets were retrospectively undersampled (overall acceleration factors combined: 4 up to 16) and subjected to CS and PI reconstruction, followed by image analysis. It is shown that a 3x3-fold acceleration (RCS x RPI) still allows for accurate assessment of cardiac functional values.

Masateru Kawakubo^1,2, Michinobu Nagao³, Seiji Kumazawa⁴, Akiko Suyama Chishaki⁴, Hiroshi Honda⁵, and Junji Morishita^4
1Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Fukuoka, Japan, ²Department of Health Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan, ³Department of Molecular Imaging & Diagnosis, Department of Clinical Radiology, Graduate School of, Kyushu University, Fukuoka, Fukuoka, Japan, ⁴Department of Health Sciences, Faculty of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan, ⁵Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan

In order to predict response to cardiac resynchronization therapy (CRT), a longitudinal strain analysis with echocardiography is used in the evaluation of mechanical dyssynchrony. Although analysis with echocardiography is restricted due to the narrow field of view (FOV), four-chamber (4CH) cine magnetic resonance imaging (MRI) has no restrictions due to the FOV and thus should allow a more precise evaluation of cardiac dyssynchrony. The longitudinal strain analysis using MRI has not been investigated in terms of cardiac dyssynchrony. We suggest an evaluation of mechanical dyssynchrony by using longitudinal strain analysis in 4CH cine MRI is useful for selecting CRT patients.

Stephen J Sawiak^1,2, Nigel I Wood³, Guido Buonincontri¹, T Adrian Carpenter¹, and A Jennifer Morton^3
1Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, England, United Kingdom, ²Behavioural and Clinical Neurosciences Institute, University of Cambridge, Cambridge, United Kingdom, ³Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom

Although incidence of heart disease is similar amongst those with and without Huntington's disease (HD), 30% of HD patients compared to 2% of non-HD sufferers will die from the disease. We examined the R6/2 mouse using cardiac MRI and found there are progressive abnormalities in morphology and function. We used a simple parameter of LV shape and showed the heart is more bent in disease carriers in this model.

Haja-Sherief N Musthafa¹, Galina Dragneva¹, Line Lottonen¹, Mari Merentie¹, Lyubomir Petrov^1,2, Tommi Heikura^1,2, Elias Ylä-Herttuala¹, Seppo Ylä-Herttuala¹, Olli Gröhn¹, and Timo Liimatainen^1
1AI Virtanen Institute For Molecular Sciences, University of Eastern Finland, Kuopio, Finland, ²Ark Therapeutics Ltd., Kuopio, Finland

In this study, we measured T1ρ relaxation times in mouse myocardium before and 1, 3, 7, 14 and 21 days after left anterior descending coronary artery ligation. T1ρ was found to increase in infarcted myocardium when compared to the reference myocardium of the same heart. Infarctions were confirmed by cine MRI and histology staining. The increase in T1ρ fits well with the time course of granulation and scar tissue formations opening up the possibilities to follow up the responses of therapeutic agents.

Francisco Contijoch¹, Walter RT Witschey^2,3, Melissa M Levack³, Jeremy M McGarvey³, Gerald A Zsido³, Manabu Takebe³, Norihiro Kondo³, Christen Dillard³, Kristina Lau³, Hee Kwon Song², Larry Dougherty², Joseph H Gorman III³, Robert C Gorman³, and James J Pilla^2,3
1Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States, ²Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, ³Department of Surgery, University of Pennsylvania, Philadelphia, PA, United States

 

Neil Woodhouse¹, Howard Mellor², Jose Ulloa¹, Guy Healing², Jason Kirk², and Paul Hockings^3
1PHB Imaging, AstraZeneca, Alderley Edge, Cheshire, United Kingdom, ²GSA, AstraZeneca, Alderley Edge, Cheshire, United Kingdom, ³PHB Imaging, AstraZeneca, Molndal, Gothenburg, Sweden

Doxorubicin induced cardiotoxicity was examined in two groups of male Han-Wistar rats (n = 6/group), Vehicle (0.9 % saline) and Dox (doxorubicin 1.25 mg/kg) using a retrospectively gated IntraGate FLASH multi-slice cine sequence at 4.7T. Gadopentetate was administered as an intravenous bolus to three rats per group. Significant differences in end systolic volume, stroke volume, ejection fraction, and fractional shortening were demonstrated between the Vehicle and Dox groups. There were statistically significant (p=0.001) differences in late gadolinium enhancement after gadopentetate infusion.

Maythem Saeed¹, Steven W Hetts¹, Loi Do¹, and Mark Wilson^1
1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, Ca, United States

The purpose was to differentiate the deleterious effects of major-vessel and micro-vessel occlusion on left ventricular function using MRI. Pigs (n=24) were divided into 3 groups: 1) control (no-infarct), 2) subjected to 90min of LAD artery occlusion/reperfusion and 3) subjected to coronary microemboli delivered into the LAD. At 3 days after coronary intervention, cine and viability images were acquired using MRI. The sizes of homogeneous infarct and microinfarct measured were 17±1% and 6.2±0.6% LV mass (P<0.01). Surprisingly, the effect on LV ejection fraction was identical in both interventional procedures, suggesting that different mechanisms govern the decline in LV function.

Shivaram Poigai Arunachalam¹, Kevin Glaser¹, Richard L Ehman¹, and Philip Araoz^1
1Radiology, Mayo Clinic, Rochester, Minnesota, United States

Previous studies have shown that cardiac MR elastography (CMRE) can assess regional differences in stiffness between infarcted and remote, noninfarcted myocardium in pigs. However, clinical applications of CMRE are challenging given the thin wall and complicated wave propagation of the myocardium. Therefore, realistic phantom studies are necessary to determine the requirements for drivers, imaging sequences and inversion algorithms for CMRE. This paper focuses on evaluating a commercially available heart phantom for CMRE using 2D EPI and 3D GRE MRE pulse sequences. The results demonstrate the feasibility of acquiring volumetric data in the thin myocardial wall of the heart phantom.

Ganesh Adluru¹, Alexis Harrison², Chris McGann², and Edward V.R. DiBella^1
1Radiology, University of Utah, Salt Lake City, UT, United States, ²Internal Medicine, University of Utah, Salt Lake City, UT, United States

Cardiac perfusion MRI without ECG gating can be a promising alternative for imaging patients with atrial fibrillation and for imaging at high field strengths. Self-gating techniques can be used to retrospectively bin ungated images into approximate systole and diastole. However cardiac and respiratory motion can still be present in these self-gated images. Here we propose a model-based deformable registration approach that uses a two-compartment contrast model to remove the residual motion. A model reference image for each image in the dynamic sequence is generated and deformable registration using a finite element based method is performed to obtain motion free images.

Octavia Biris^1,2, Saurabh Shah³, Christopher Glielmi³, Daniel C Lee⁴, James C Carr¹, and Timothy J Carroll^1,2
1Radiology, Northwestern University, Chicago, IL, United States, ²Biomedical Engineering, Northwestern University, Evanston, IL, United States, ³Customer Solutions Group, Siemens Medical Solutions USA, Inc., Chicago, IL, United States, ⁴Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, IL, United States

Absolute quantification of myocardial blood volume (ml/100g) may provide important information about myocardial viability in coronary artery disease and in heart transplants, where the formation of fibrotic tissue and global MBV reduction in the myocardium precedes organ rejection. We show a first observation of quantitative myocardial blood volume and water proton exchange in human volunteers with an intravascular contrast agent. Myocardial blood volume was calculated pixel-by-pixel from steady-state T1-weighted signal before and after administration of contrast agent. We show intra- to extra-vascular water exchange in the myocardium to fit a previously published two compartment slow water exchange model.

Adrienne E Campbell^1,2, Anthony N Price³, Mark F Lythgoe¹, Roger J Ordidge⁴, and Dave L Thomas^5
1Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, United Kingdom, ²Department of Medical Physics and Bioengineering, University College London, London, United Kingdom, ³Robert Steiner MRI Unit, Imaging Science Department, Hammersmith Hostpital, Imperial College London, London, United Kingdom, ⁴Centre for Neuroscience, University of Melbourne, Melbourne, Australia, ⁵Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, University College London, London, United Kingdom

Look-Locker arterial spin labelling (ASL) is used for the measurement of myocardial perfusion in preclinical studies. Saturation effects from Look-Locker acquisition will become particularly relevant in the heart when acquiring multi-slice ASL data, which requires thicker slice-selective inversions and additional RF pulses. In this study, we have taken the preliminary steps toward developing a 3-compartment iterative ASL model for the heart which includes the effects of the Look-Locker acquisition, in order to model the ASL acquisition.

Song Chen¹, Jia Zhong¹, Hualei Zhang^1,2, Hui Qiao^1,3, Rachel S. Frank¹, Jerry Glickson¹, and Rong Zhou^1,3
1Laboratories of Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States, ²Department of Bioengineering, University of Pennsylvania, ³Cardiovascular Institute, University of Pennsylvania

Doxorubicin (DOX) remains among the most potent and widely prescribed drug for treating breast, blood and pediatric cancers. However, severe cardiotoxicity continues to affect up to 20% of patients receiving DOX. Unfortunately, currently available methods in the clinic cannot predict or discriminate patients who will suffer from cardiomyopathy after exposure to DOX. Here we show spin labeling cardiac MR reveals an early decline in myocardial blood flow in response to DOX when LVEF is still normal. With further investigation, we hope to develop a sensitive, non-invasive prognostic tool to improve cardiac risk stratification in the management of DOX-treated patients.

David Chen^1,2, Behzad Sharif¹, Louise Thomson^1,3, Troy LaBounty¹, Rohan Dharmakumar^1,3, Daniel Berman^1,3, and Debiao Li^1
1Cedars Sinai Medical Center, Los Angeles, CA, United States, ²Northwestern University, Evanston, IL, United States, ³University of California, Los Angeles, CA, United States

This work describes method to correct for saturation in the arterial input function (AIF) for cardiac perfusion using a multi-shot radially acquired data. Single cardiac cycle resolution T1 mapping is possible with this technique. T1 can then be converted to Gd concentration. This method eliminates the need to acquire two datasets, increasing feasibility for clinical use.

Ramez E. N. Shehada¹, Rohan More¹, Sassan Rahbari¹, Richard Williamson¹, and Ali Dianaty^1
1CRMD, St. Jude Medical, Sylmar, California, United States

MRI conditional pacemaker leads may increase in temperature primarily due to RF-induced heating; however, large segments of the leads reside in blood vessels and can benefit from the cooling effect of the surrounding blood flow. An in-vitro flow setup was developed to simulate in-vivo flow conditions around pacemaker leads and was used to determine the percent temperature reduction in the lead due to blood flow. Blood flow may reduce temperature-rises in the distal end of pacemaker leads by 83-87% and can be used to mitigate moderate heating of the distal segments of MRI conditional pacemaker leads.

Behzad Sharif¹, Rohan Dharmakumar¹, Chrisandra Shufelt², Troy LaBounty², Louise Thomson², Noel Bairey Merz², Daniel S. Berman², and Debiao Li^1
1Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, and University of California Los Angeles, Los Angeles, California, United States, ²Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States

Current clinical myocardial perfusion MR methods suffer from image artifacts that reduce diagnostic accuracy, specifically the so-called subendocardial dark-rim artifact (DRA). DRAs are caused by multiple factors and mimic subendocardial perfusion deficits, and are especially limiting since they can reduce the sensitivity/specificity of detecting subendocardial perfusion deficits. In this work, we demonstrate that projection imaging of first-pass cardiac perfusion MR is robust to Gibbs ringing, which is a major cause of DRAs; thereby proposing radial k-space sampling as the preferred acquisition scheme for DRA-free perfusion imaging.

Thibaut Capron¹, Thomas Troalen¹, Patrick J. Cozzone¹, Monique Bernard¹, and Frank Kober^1
1Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR CNRS N°6612, Faculté de Médecine, Aix-Marseille Université, Marseille, France

The FAIR-ASL method, applied to the heart, has key limitations due to the relaxation of the labeled magnetization during the experiment. We propose a new steadily-pulsed ASL experimental scheme that allows maintaining the tagged state, simultaneously with cine-imaging. We provide a theoretical description of such a scheme and show a close agreement with the behavior observed in a proof-of-concept experiment carried out in mice heart. The calculations thus allow for a reliable assessment of myocardial perfusion. Furthermore, theory predicts that the acquisition efficiency can be enhanced by a factor of 3 with respect to the widely used FAIR technique.

Stefan Weber^1,2, Karl-Friedrich Kreitner², and Laura Maria Schreiber^1,2
1Section of Medical Physics, Department of Diagnostic and Interventional Radiology, University Medical Center Mainz, Mainz, Rheinland-Pfalz, Germany,²Department of Diagnostic and Interventional Radiology, University Medical Center Mainz, Mainz, Germany

The aim of this study was to compare at 3.0T SR-TrueFISP and SR-TurboFLASH pulse sequences for semi-quantitative and absolutequantitative assessment of the myocardial perfusion reserve. No differences were found in SNR and CNR between both pulse sequences. However, SR-TrueFISP yielded superior reproducibility than SR-TurboFLASH as well as absolutequantification using the MMID4 model yielded lower intraobservervariability than the semiquantitative method.

Michael C Langham¹, and Felix W Wehrli^1
1Radiology, University of Pennsylvania, Philadelphia, PA, United States

The current temporal resolution of dynamic oximetry is limited to 5s and thus may not be able to resolve potentially important information that could differentiate subtle differences in the vascular reactivity. Reducing TR is not a satisfactory solution since it will lead to unacceptable SNR in reference tissue as well as a minor loss of blood signal due to saturation effect. In this work we implemented and evaluated the keyhole acquisition scheme for improving the temporal resolution of dynamic oximetry by a factor of four without sacrificing SNR and accuracy.

Andreas Max Weng¹, Christian Oliver Ritter¹, Sven Zuehlsdorff², Hui Xue³, Jens Guehring³, Christopher Glielmi², Meinrad Beer¹, Dietbert Hahn¹, and Herbert Köstler^1
1Institute of Radiology, University of Würzburg, Würzburg, Bayern, Germany, ²MR Research and Development, Siemens Healthcare, ³Corporate Research, Siemens Corporation

Absolute quantification of myocardial perfusion is commonly based on a region-of-interest (ROI) analysis in order to achieve a sufficient signal to noise ratio (SNR). 3 T scanners provide the opportunity to acquire dynamic contrast enhanced MRI with higher SNR compared to 1.5 T. This, in turn, may help to absolutely quantify myocardial perfusion not only in ROIs but in every acquired voxel. This study presents first results of a voxelwise myocardial perfusion quantification.

Behzad Sharif¹, Rohan Dharmakumar¹, Louise Thomson², Noel Bairey Merz², Daniel S. Berman², and Debiao Li^1
1Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, and University of California Los Angeles, Los Angeles, California, United States, ²Heart Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States

A major limiting factor for specificity and sensitivity of current MP MR methods is the so-called subendocardial dark-rim artifact (DRA), which may mimic perfusion deficits. It is known that DRAs in conventional Cartesian imaging protocols are caused by a combination of factors including Gibbs ringing and cardiac motion effects. In this work, we aimed at improving the analysis of motion-induced DRAs by considering the combined effect of cardiac motion and limited spatial resolution (Gibbs ringing) on both the spatial extent and temporal persistence of the DRA. We performed first-pass MP MR on healthy dogs at moderate to high heart-rates to evaluate the effect of motion on the DRAs in terms of their spatial extent and temporal persistence. In addition, we present initial results for an alternative highly-accelerated radial acquisition and reconstruction scheme that can potentially eliminate the DRA due to motion.

Grzegorz Bauman¹, Rajiv Gupta², and Julien Dinkel^2,3
1Dept. of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany, ²Dept. of Radiology, Massachusetts General Hospital, Boston, United States, ³Dept. of Radiology, German Cancer Research Center, Heidelberg, Germany

In this work we present a technique for myocardial perfusion assessment by using contrast-agent-free MRI at 3T. In this feasibily study the data were obtained in a group of healthy volunteers. The proposed method is based on fast data acquisition with an interleaved radial gradient echo sequence combined and compressed sensing image reconstruction. Subsequent postprocessing including image registration, segmentation and spectral analysis of signal variations in myocardium was used to generate perfusion-weighted images as well as maps of temporal distribution of the blood flow.

Anthony G. Christodoulou¹, Haosen Zhang², Bo Zhao¹, Qing Ye², T. Kevin Hitchens², Chien Ho², and Zhi-Pei Liang^1
1Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States, ²Pittsburgh NMR Center for Biomedical Research, Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, United States

This abstract presents a novel method for performing high-resolution 3D first-pass myocardial perfusion imaging. Parallel imaging and sparse sampling are integrated to vastly improve the temporal resolution of first-pass myocardial perfusion imaging. The method is demonstrated in vivo in rats.

Aya Kino¹, Andrada R Popescu², Mauricio S Galizia¹, Jeremy D Collins¹, Darshit Thakrar¹, Rhaul Rustogi¹, Christopher Glielmi³, Hui Xue⁴, Jens Guehring⁴, Sven Zuehlsdorff⁵, Daniel Lee⁶, and James Carr^1
1Northwestern University, Chicago, IL, United States, ²Radiology, Children Memorial Hospital, Chicago, IL, United States, ³Siemens Healthcare, Siemens,⁴Corporate Research USA, Siemens, Princenton, New Jersey, ⁵Siemens Healthcare, Siemens, Chicago, IL, ⁶Medicine Cardiology Division, Northwestern University, Chicago, IL

The purpose of the study is to evaluate a fully automated motion corrected first pass myocardial perfusion (FPMP) MRI with semi quantitative perfusion parameter maps in patients with suspected ischemic heart disease

Hao Shen¹, Guang Cao², Haiyi Wang³, and Jia Wang^3
1Applied Science Laboratory, GE Healthcare, Beijing, Beijing, China, ²Applied Science Laboratory, GE Healthcare, HongKong SAR, China, ³Department of Radiology, Chinese PLA General Hospital, Beijing, China

Abdominal venography is important in clinical diagnosis of several diseases, but it is difficult to image with the existing MRI technique. In this study, we developed a non-contrast-enhanced abdominal venography using inflow spin labeling in combination with flow dephased background suppression.

Bing Wu¹, Jiayu Sun², Changxian Li², and Zhenlin Li^2
1West China Hospital, Chengdu, Sichuan, China, ²West China Hospital

To evaluate the diagnostic performance of non-contrast-enhanced MR angiography (NCE-MRA) with contrast-enhanced MR angiography (CE-MRA) in the preoperative assessment of renal artery. Results showed no statistically significant differences between NCE-MRA and CE-MRA for characterization of renal vasculature(P<0.05).

Jianing Pang^1,2, Himanshu Bhat³, Behzad Sharif¹, Zhaoyang Fan¹, Edward Gill¹, Troy LaBounty¹, James Min¹, Louise E.J. Thomson¹, John D. Friedman¹, Daniel S. Berman¹, and Debiao Li^1,4
1Cedars-Sinai Medical Center, Los Angeles, CA, United States, ²Northwestern University, Chicago, IL, United States, ³Siemens Medical Solutions USA Inc., Charlestown, MA, United States, ⁴University of California, Los Angeles, CA, United States

A respiratory motion correction method (SEGMO) is proposed for whole-heart coronary MRA. It eliminates the need for a diaphragm navigator, reduces imaging setup time, and has more accurate respiratory motion detection using an affine model. Its inherent 100% gating efficiency ensures a shorter and more fixed scan time compared to conventional navigator gated schemes.

Holden H Wu^1,2, Bob S Hu^2,3, Dwight G Nishimura², and Michael V McConnell^1,2
1Cardiovascular Medicine, Stanford University, Stanford, CA, United States, ²Electrical Engineering, Stanford University, Stanford, CA, United States, ³Palo Alto Medical Foundation, Palo Alto, CA, United States

Non-invasive coronary angiography is one of the most desired applications of cardiovascular MRI, but is challenged by physiologic motion. In this work, we present new advances in respiratory motion compensation for the 3D cones multi-phase whole-heart imaging technique. Leading and trailing 2D navigator images are acquired every heartbeat in orthogonal planes through the heart to directly track respiration-induced displacement in all three directions (S/I, A/P, L/R). Tracking results are then used to retrospectively compensate all readouts (100% acquisition efficiency) prior to image reconstruction.

Christoph Forman^1,2, Davide Piccini¹, Jana Hutter^1,2, Robert Grimm¹, Joachim Hornegger^1,2, and Michael O. Zenge^3
1Pattern Recognition Lab, University of Erlangen-Nuremberg, Erlangen, Germany, ²Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany, ³MR Application & Workflow Development, Siemens AG, Healthcare Sector, Erlangen, Germany

Current research in whole-heart coronary MR imaging is driven by acceleration of scan time. On the one hand, self-navigation was introduced to improve the efficiency of conventional navigator-gated examinations. On the other hand, compressed sensing was proposed for acceleration of data acquisition. In this work, a novel incoherent Cartesian sampling pattern is used for imaging the coronary imaging in multiple breath-holds. Self-navigation properties are exploited for a real-time supervision the respiratory phase during breath-hold. In this way, misregistration of consecutive acquisitions could be avoided. The proposed method was compared with the navigator-gated approach in 4 volunteers.

Gabriele Bonanno^1,2, Gilles Puy^3,4, Yves Wiaux^3,5, Ruud B. van Heeswijk^1,2, and Matthias Stuber^1,2
1Department of Radiology, University Hospital (CHUV) and University of Lausanne, Lausanne, Vaud, Switzerland, ²Center for Biomedical Imaging (CIBM), Lausanne, Vaud, Switzerland, ³Institute of Electrical Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Vaud, Switzerland, ⁴Institute of the Physics and Biological Systems, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Vaud, Switzerland, ⁵Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Vaud, Switzerland

A novel image-based respiratory self-navigation method was developed for free-breathing coronary MRI. Under-sampled radial sub-images are acquired on a beat-to-beat basis, non-linear reconstruction is performed, and motion parameters are extracted for direct motion correction. In a first step, the new algorithm was optimized and evaluated using a numerical simulation of a moving heart. Subsequently, the performance was quantitatively ascertained in an in vivo study that included 12 healthy adult subjects where it was objectively demonstrated that self-navigation incorporating compressed sensing is a powerful tool for motion artifact suppression in radial coronary MRI.

Naoyuki Takei¹, Yuji Iwadate¹, Takayuki Suzuki², Koji Yoneyama², Takayuki Masui², and Hiroyuki Kabasawa^1
1Global Applied Science Laboratory, GE Healthcare, Hino, Tokyo, Japan, ²Radiology, Seirei Hamamatsu General Hospital, Japan

The purpose of this study was to develop a prospective navigator echo based cardiac triggering for coronary artery imaging (CAI). Echo peak from FID signal acquired using 2D selective navigator pulse with 10mm in diameter that was placed on aortic arch was used for cardiac triggering. The magnitude of echo peak from the FID was displayed on a real-time monitor window. Systole was detected by a rise in echo peak above a threshold. Data was acquired with Balanced Steady State Free Precession (bSSFP) data acquisition with spectral selective inversion pulse for fat saturation (SPIR) with breath hold. The comparison study was performed to a conventional ECG trigger approach on 1.5T. The preliminary results provide a comparable depiction of coronary arteries to ECG without the constraints of scan time, spatial resolution and image quality.

Christoph Forman^1,2, Davide Piccini¹, Jana Hutter^1,2, Robert Grimm¹, Joachim Hornegger^1,2, and Michael O. Zenge^3
1Pattern Recognition Lab, University of Erlangen-Nuremberg, Erlangen, Germany, ²Erlangen Graduate School in Advanced Optical Technologies (SAOT), Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany, ³MR Application & Workflow Development, Siemens AG, Healthcare Sector, Erlangen, Germany

Recently, self-navigation techniques were introduced for 3D radial in the field of free-breathing, whole-heart coronary imaging. Radial trajectories intrinsically are insensitve for motion during data acquisition. However, Cartesian sampling is superior to radial trajectories in terms of SNR and hardware limitations, e.g. gradient delays. Thus, we propose the application of respiratory self-navigation on an incoherent, undersampled Cartesian trajectory. The effects of residual respiratory motion are minimized by a weighted data fidelity term, exploiting the information derived from the self-navigation, in iterative image reconstruction. In-vivo experiments were performed on four healthy volunteers and compared to navigator-gated acquisition.

Jianing Pang^1,2, Behzad Sharif¹, Troy LaBounty¹, Louise E.J. Thomson¹, Daniel S. Berman¹, and Debiao Li^1,3
1Cedars-Sinai Medical Center, Los Angeles, CA, United States, ²Northwestern University, Chicago, IL, United States, ³University of California, Los Angeles, CA, United States

Proposed method combines sensitivity encoding and undersampled projection reconstruction trajectory to greatly accelerate whole-heart coronary MRA. No separate calibration scans are needed since the densely sampled k-space central region allows direct sensitivity map extraction from image data. Results show that the proposed method reduces aliasing, hence allows a shorter scan time by acquiring less k-space samples, while minimizing the reduction in image quality.

Davide Piccini¹, Arne Littmann², Hui Xue³, Jens Guehring², and Michael O. Zenge^2
1Pattern Recognition Lab, University of Erlangen-Nuremberg, Erlangen, Germany, ²MR Applications & Workflow Development, Siemens AG, Healthcare Sector, Erlangen, Germany, ³Imaging and Visualization, Siemens Corporate Research, Princeton, NJ, United States

In recent approaches implementing image-based 3D respiratory motion correction for interleaved whole-heart coronary MRA, the interleaves are straightforwardly grouped in equally spaced bins on the respiratory cycle. This allows to obtain undersampled images with minimal intra-bin respiratory motion that can be registered to a reference. However, for bins with a low number of interleaves or non-uniform spatial distribution, image quality is degraded by streaking and undersampling artifacts. Hence, image registration might fail and such bins are usually discarded. In this work an optimized binning approach is proposed which maximizes the uniformity of the distribution of the interleaves. With this method 3D affine motion correction is allowed for all bins.

Huijun Chen¹, Jinnan Wang², Xihai Zhao³, Chun Yuan¹, and William S Kerwin^1
1University of Washington, Seattle, WA, United States, ²Philips Research North America, United States, ³Department of Biomedical Engineering, Tshinghua University, Beijing, China

SNAP sequence has been proposed to image both the luminal stenosis and intraplaque hemorrhage in atherosclerosis patient in one scan. In SNAP, the blood signal presents only negative signal that can be used to generate non-contrast MRA, while all other tissues presents T1-weighted positive signal, providing a good hemorrhage detection tool. However, the phase-sensitive reconstruction in the SNAP sequence requires a full-resolution reference scan, which doubles the scan time. In this study, we propose a fast SNAP (fSNAP) sequence with low resolution reference scan and a corrected phase-sensitive reconstruction to speed up the acquisition without compromising the image quality.

Petter Dyverfeldt¹, Vibhas S Deshpande², Tobias Kober³, Gunnar Krueger³, and David Saloner^1
1Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, ²Siemens Medical Solutions USA, Inc., San Francisco, CA, United States, ³Advanced Clinical Imaging Technology, Siemens Healthcare Sector IM&WS S, Lausanne, Switzerland

Multicontrast-weighted MRI is promising for characterization of carotid plaques, but is hampered by motion artifacts. This study demonstrated initial feasibility of motion-compensated carotid-MRI achieved by a novel approach to FID-based navigator gating. The results demonstrate the potential of the proposed gating-approach to improve the clinical capability of MR imaging of carotid plaques.

Stephanie Elaine Gar-Wai Chiu¹, James Q Zhan², and Alan R Moody^1,2
1Medical Biophysics, University of Toronto, Toronto, Ontario, Canada, ²Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

Intraplaque hemorrhage (IPH) may be an important marker of complicated atheroma. IPH was simulated by microinfusion catheter delivery of autologous red blood cells (RBCs) into advanced rabbit abdominal aorta plaques. Histology at 9 weeks after simulated IPH indicated the development of plaque features not previously seen in rabbits undergoing similar atherosclerosis induction without RBC injection. These plaque features include necrotic cores, extravasated RBCs, and iron deposits. T1-weighted MR imaging was able to show varying vessel wall thickness and post-contrast vessel wall enhancement indicative of the large plaque sizes and extensive inflammation and neovascularization.

Ioannis Koktzoglou^1,2, and Robert R Edelman^1
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, ²The University of Chicago Pritzker School of Medicine, Chicago, IL, United States

Swallowing is reported to be greatest source of physiologic motion within the carotid arteries. The purpose of this work was to investigate whether image-based (i.e., 2D) navigators depicting the carotid arteries and adjacent tissue could be used to identify motion and ameliorate image artifacts during three-dimensional carotid vessel wall imaging.

Jinnan Wang¹, Niranjan Balu², Peter Börnert³, and Chun Yuan^2
1Philips Research North America, Briarcliff Manor, NY, United States, ²University of Washington, ³Philips Research Europe

Intracranial atherosclerotic disease (IAD) represents 9-15% of all the ischemic strokes in US and is suggested as the most common cause of stroke worldwide. The vessel wall imaging of IAD, however, is challenged by blood suppression and outer wall boundary delineation. This study proposed a new T1 enhanced iMSDE sequence for IAD vessel wall imaging and demonstrated its feasibility in a group of subjects.

Jie Sun¹, Yan Song², William S Kerwin¹, Huijun Chen¹, Dong Li³, Daniel S Hippe¹, Min Chen², Cheng Zhou², Thomas S Hatsukami⁴, and Chun Yuan^1
1Radiology, University of Washington, Seattle, Washington, United States, ²Radiology, Beijing Hospital, Beijing, China, ³Radiology, Anzhen Hospital, Beijing, China,⁴Surgery, University of Washington, Seattle, Washington, United States

Substantial evidence indicates that adventitial vasa vasorum (VV) is actively involved in the atherogenic process. However, non-invasive methods to study adventitial VV quantitatively are limited. This study characterized adventitial VV in symptomatic patients using dynamic contrast-enhanced MRI (DCE-MRI). Adventitial Ktrans derived from DCE-MRI was found to be closely associated with IPH and clinical symptom status. DCE-MRI provides a noninvasive way to study adventitial VV in patients and may be useful in understanding plaque progression or individual risk stratification.

Dongxiang Xu¹, Jinnan Wang², William S Kerwin¹, and Chun Yuan^1
1Radiology, University of Washington, Seattle, WA, United States, ²Philips Research North America, Seattle, WA, United States

Intracranial atherosclerotic disease (IAD) is one of the most common causes of stroke worldwide. Clinically, IAD is usually diagnosed with angiography based imaging methods to detect luminal narrowing. However, autopsy studies2 show that approximately 40% of IAD does not present with any luminal stenosis but rather only outer wall remodeling, an indicator of progression of plaque burden. To overcome this underestimation of stroke risk, analysis of the intracranial vessel wall (IVW) is crucial. Recent developments in 3D isotropic MR imaging techniques provide sufficient wall contrast in in vivo MR IVW images. Due to the tortuous topology of intracranial vessels, cross sectional images reformatted based on the geometry of the arteries are desirable. However, no approaches have thus far been proposed to effectively analyze IVW images, and most current IVW analysis is still limited to arterial sections that are approximately straight. In this study, we proposed a new approach that allows effective evaluation of atherosclerotic plaques at all locations along intracranial arteries by using 3D isotropic multi-contrast MRI.

Kiyofumi Yamada¹, Martine Truijman², William Kerwin¹, Jie Sun¹, Yan Song³, Mat Daemen², Eline Kooi², and Chun Yuan^1
1Radiology, University of Washington, Seattle, Washington, United States, ²Maastricht University Medical Center, Maastricht, Netherlands, ³Radiology, Beijing Hospital, Beijing, China

The purpose of this investigation was to understand the cross-center similarities and differences of two independent carotid vessel wall imaging centers. Ten subjects were recruited from each of two imaging centers for multicontrast MRI and plaque compositional analysis. We found good association across centers suggesting similar results regarding the association of risk factors with outcome can be expected across centers. On the other hand, considerable biases between absolute values of quantitative parameters were observed. Thus, in order for risk factors to be translated into clinical practice with appropriate risk thresholds, the source of bias must be ascertained and eliminated.

Rui Li¹, and Chun Yuan^1,2
1Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing, China, ²Department of Radiology, University of Washington, Seattle, WA, United States

Visualization of fibrous cap in atherosclerotic plaque is critical for plaque imaging, since thin fibrous cap means vulnerable plaque. Several studies have shown the capability of high resolution MRf imaging to discriminate fibrous cap and lipid rich necrotic core. However the minimum thickness can be seen has not been investigated yet. This study proposed to find out the answer using a home-designed phantom. In conclusion we found fibrous cap thinner than the acquisition resolution is hardly to be seen with 1/2 contrast hypnosis between fibrous cap and necrotic core.

Julia Busch¹, Signe Johanna Vannesjoe¹, Daniel Giese^1,2, Christoph Barmet¹, Klaas Pruessmann¹, and Sebastian Kozerke^1,2
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, ²Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, United Kingdom

Phase-contrast magnetic resonance imaging provides high resolution information about blood flow, however its application in a clinical setting is still limited due to its sensitivity to phase errors. Phase oscillations caused by mechanical vibrations of the gradient coils account for various degrees of phase offsets depending on the echo time point. A generic system-specific pre-emphasis would offer the possibility to compensate for 0th and 1st order phase offsets without the disadvantage of causing additional scan time. Focusing on the mechanical vibrations of the z-gradient it is demonstrated that pre-emphasis can reduce phase errors well below 1% of the encoding velocity.

Yongjun Kwak^1,2, Seunghoon Nam^1,2, Mehmet Akcakaya¹, Tamer A. Basha¹, Beth Goddu¹, Warren J. Manning¹, Vahid Tarokh², and Reza Nezafat^1
1Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States, ²SEAS, Harvard University, Cambridge, MA, United States

One of the major limitations of phase contrast imaging is its long scan time. In this study, we propose an accelerated phase contrast MR approach in which the sparsity of the complex difference (CD) image is used as the sparsifying transform to improve the compressed sensing (CS) reconstruction. The efficacy of the proposed method was demonstrated in both retrospective undersampling and prospective accelerated flow imaging in ascending aorta.

Jacob U Fluckiger¹, Jeffrey Goldberger¹, Daniel Lee², Richard Lee², Jason Ng², James Carr¹, and Michael Markl^1
1Radiology, Northwestern University, Chicago, Il, United States, ²Cardiology, Northwestern University, Chicago, Il, United States

In this work we present preliminary results measuring blood velocity in patients with atrial fibrillation. 4D phase contrast MRI data was collected in 9 patients with AF as well as 10 healthy volunteers. The AF patients had an average velocity that was 39% lower than healthy volunteers.

Christian Binter¹, Verena Knobloch¹, Robert Manka^1,2, Andreas Sigfridsson¹, and Sebastian Kozerke^1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, ²Cardiac Imaging, University Hospital Zurich, Zurich, Switzerland

Aortic valve performance is typically assessed by means of pressure gradients or orifice sizes, which correlate only weakly with the energy loss across the valve. Here a method to directly determine the energy budget of the flow is presented. Using generalized phase-contrast flow measurements with multiple velocity encodings the energy loss due to turbulence and regurgitation can be quantified. By relating these losses to the available kinetic energy of the flow, a parameter for the efficiency of heart valves can be obtained. It is shown that significant differences in energy efficiency between different valve designs and between heart valve patients and healthy controls exist.

Mehmet A. Gulsun¹, Marie-Pierre Jolly¹, Jens Guehring², Christoph Guetter¹, Arne Littmann², Andreas Greiser², Michael Markl³, and Aurelien F. Stalder^2
1Image Analytics and Informatics, Siemens Corporate Research, Princeton, NJ, United States, ²Siemens AG Healthcare Sector, Erlangen, Germany,³Northwestern University, Chicago, Illinois, United States

4D Phase Contrast (PC)-MRI is gaining attention for assessing blood flow. Therefore the accuracy and reproducibility of this process becomes critical. We present a comprehensive 4DFlow software package for advanced flow quantification and visualization. This software integrates background phase and velocity aliasing corrections, 4D vascular centerline and lumen segmentation, automated quantification and 3D visualization. Five cases were evaluated giving inter-method and inter-observer errors within 10% of the measured dimension. Results demonstrate that an integrated 4D flow post-processing approach can reduce processing times to a few minutes while enhancing accuracy and objectivity and thus help bring the technique to the clinic.

Verena Knobloch¹, Christian Binter¹, Utku Gulan², Beat Lüthi², Peter Boesiger¹, and Sebastian Kozerke^1
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, ²Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland

Velocity vector fields and Turbulent Kinetic Energy (TKE) were acquired in an elastic and anatomically accurate replica of a human aorta equipped with a mechanical heart valve. Using the MRI acquisition of a multi-point velocity encoded sequence, velocities and TKE were computed with Bayesian parameter estimation. As a reference, both parameters were measured with Particle Tracking Velocimetry in the transparent setup. The comparison of both measurements shows good agreement for velocity and TKE values.

Grzegorz Tomasz Kowalik¹, Jennifer Anne Steeden¹, Bejal Pandya¹, David Atkinson², Andrew Taylor¹, and Vivek Muthurangu^1
1Institute of Cardiovascular Science, UCL Centre for Cardiovascular Imaging, London, United Kingdom, ²Centre for Medical Imaging, UCL Division of Medicine, London, United Kingdom

A novel approach for continuous cardiac output quantification during an exercise was developed and implemented on a heterogeneous image reconstruction system. Combination of spiral real-time PCMR sequence with parallel imaging allowed on high-temporal acquisition. Application of a GPU for image processing resulted in almost instantaneous reconstruction. An external computer equipped with the GPU was networked using CORBA technology. This let on seamless processing from a clinician point of view. The implementation was tested and validated against our multi -core CPU

Wouter V. Potters¹, Pim van Ooij^1,2, Ed vanBavel², and Aart J. Nederveen^1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, Netherlands

Wall shear stress (WSS) is the tangential force of flowing blood on the vessel wall. Calculation of WSS remains challenging. A novel method is presented to calculate time-resolved vectorial WSS along the entire vessel wall. The method was validated in software phantoms and in-vivo datasets of the common carotid artery at multiple resolutions. Results showed convergence of WSS towards theoretical WSS for the phantom data, which effect was reproduced in in-vivo data.

Thales Henrique Dantas¹, and Joao L. A. Carvalho^1
1Department of Electrical Engineering, University of Brasília, Brasília, DF, Brazil

Fourier velocity encoding (FVE) may be useful in the assessment of valvular disease and of carotid wall shear stress, as it eliminates partial volume effects that affect phase-contrast imaging. The scan-time of 2DFT FVE is prohibitively long for clinical use, but the spiral FVE method is substantially faster. Spiral FVE reconstruction is time-consuming, due to multidimensionality and non-Cartesian sampling. Using gridding or NUFFT, the entire m(x,y,v,t) matrix is calculated. However, we are typically only interested in the velocity distributions associated with pixels in a small ROI. We propose single-voxel direct Fourier transform (DrFT) on GPGPUs for seemingly instantaneous spiral FVE reconstruction.

Alexander Gotschy^1,2, Volker Herold¹, Elisabeth Bauer², Gunthard Lykowsky³, Christian Schrodt², Eberhard Rommel¹, Peter M. Jakob¹, and Wolfgang R. Bauer^1
1Department of Experimental Physics 5, University of Würzburg, Würzburg, Germany, ²Department of Internal Medicine I, University of Würzburg, Würzburg, Germany, ³Research Center Magnetic Resonance Bavaria (MRB), Würzburg, Germany

Increased aortic stiffness is known to be associated with atherosclerosis. However, to our knowledge, the local distribution of vascular stiffening has never been investigated in detail. A local indicator for the elasticity of the vessel wall is the Pulse-Wave-Velocity (PWV). In this study we assessed regional and local PWV in the descending aortas of ApoE-/- and control mice and evaluated the correlation of both parameters. Thereby we found that local and regional PWV show a good correlation in control mice but no correlation in ApoE-/- mice. This may indicate that vascular stiffening is very unequally distributed over the vessel.

Pim van Ooij^1,2, Joppe Schneiders¹, Henk A. Marquering^1,2, Charles B. Majoie¹, Ed vanBavel², and Aart J. Nederveen^1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, Netherlands

4D phase contrast MRI measurements (4D PC-MRI) in intracranial aneurysms are presented and compared with patient-specific computational fluid dynamics in which a 4D velocity profile as measured with through-plane PC-MRI (2D PC-MRI) is prescribed as inflow boundary conditions. Quantitative and qualitative similarities were found. Although the inflow velocity assumption in CFD is minimized by using the 2D PC-MRI measurement, other assumptions cause deviations from measured flow patterns. However, in CFD the resolution is higher and results show more flow details. Thus, for hemodynamic assessment, CFD and 4D PC-MRI complement each other.

Deirdre B Cassidy¹, Stephen J Gandy^2,3, Patricia Martin³, R Stephen Nicholas^2,3, and J Graeme Houston^3,4
1Institute of Cardiovascular Research, Dundee, Angus, United Kingdom, ²NHS Tayside Medical Physics, Ninewells Hospital, Dundee, Angus, United Kingdom, ³NHS Tayside Clinical Radiology, Ninewells Hospital, Dundee, Angus, United Kingdom, ⁴Institute of Cardiovascular Research, Dundee, Scotland, United Kingdom

Aortic stiffening occurs as a result of the pathophysiological contribution of age and atherosclerosis, and is associated with increased risk of cardiovascular events. This can be characterised by measurement of pulse wave velocity (PWV). PWV can be derived from phase contrast MRA using multiple aortic flow waveforms in combination with intra-arterial distance measurements. In this study, the mean PWV was found to be stable on a ‘scan-to-scan’ basis in a cohort of healthy volunteers, and was found to increase significantly with age and cardiovascular disease severity – i.e. the data are consistent with developing aortic stiffness.

Pim van Ooij^1,2, Wouter V. Potters¹, Charles B. Majoie¹, Ed vanBavel², and Aart J. Nederveen^1
1Radiology, Academic Medical Center, Amsterdam, Netherlands, ²Biomedical Engineering & Physics, Academic Medical Center, Amsterdam, Netherlands

Due to limited resolution and SNR, estimating wall shear stress (WSS) from time-resolved 3D phase contrast MRI is challenging. In this study, a recently in-house developed WSS algorithm is tested on 3D PC-MRI data obtained in an intracranial aneurysm phantom, measured with steady flow at different resolutions. Flow patterns are similar, albeit with more detail at higher resolutions. The maximum and mean WSS increased with increasing resolution. Directions of WSS vectors and regions were similar. More WSS complexity could be observed at higher resolutions. For accurate WSS estimations, resolution must be as high as possible.

Andy Swift¹, Adam Telfer², Smitha Rajaram², Robin Condliffe³, Helen Marshall², Dave Capener², Judith Hurdman³, Charlie Elliot³, David Kiely³, and Jim Wild^2
1University of Sheffield, Sheffield, S.Yorks, United Kingdom, ²University of Sheffield, ³Sheffield Pulmonary Vascular Disease Unit

Based on a simple fluid dynamics model of plug flow, we evaluated 3D MR contrast transit times in 59 patients with pulmonary hypertension. Regression curve fitting identified significant inverse proportional relationships between cardiac index and 3D MR angiography measurements. Direct proportional relationships that have been previously reported with pulmonary arterial pressure and resistance were not found to be either physically realistic, or strong in correlation with 3D MR angiography transit times from our plug flow model.

Julio Garcia¹, Lyes Kadem², Eric Larose¹, and Philippe Pibarot^1
1Medicine, Laval University, Quebec, Quebec, Canada, ²Concordia University, Montreal, Quebec, Canada

Aortic valve eccentricity measurement may be related to valve hemodynamic in patients with aortic stenosis (AS). However, it is difficult to characterize with transthoracic Doppler echocardiography velocity measurements. Flow velocity eccentricity can be estimated from CMR phase-contrast flow velocity measurements using jet displacement and flow velocity angle. The aim of this study is to characterize aortic valve eccentricity on aortic stenosis patients. Aortic flow velocity eccentricity parameters showed to be able to characterize transvalvular flow hemodynamic on AS patients and may provide further information about patient outcome.

Volker Herold¹, Alma Zerneck², Alexander Gotschy¹, Eberhard Rommel¹, Wolfgang Rudolf Bauer², and Peter Michael Jakob^1
1Experimental Physics 5, University of Würzburg, Würzburg, Bavaria, Germany, ²Medizinische Universitätsklinik, University of Würzburg

Quantification of the vessel wall function in mouse models by estimating the pulse wave velocity (PWV) has emerged as an important predictor of cardiovascular risk. Usually transit-time methods (TT) to quantify the averaged regional PWV and local PWV measurements using QA-methods (Q: volume flow; A: cross-sectional area) are applied. However, no comparison of these techniques have yet been performed with MR-based imaging in particular not in the carotid arteries. In this paper we present a multi-site-TT approach to calculate at the first time the regional PWV in the carotid artery and compare these results with local PWV values

Kathryn M Broadhouse¹, Anthony N Price¹, Giuliana Durighel¹, Anna E Finnemore¹, David J Cox¹, Alan M Groves¹, A David Edwards¹, and Jo V Hajnal^1
1Robert Steiner Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College, London, United Kingdom

This study looks at the feasibility of measuring pulse wave velocity (PWV) using PC-MRI in neonates and seeks to identify any changes in PWV associated with patent ductus arteriosus (PDA). PWV was quantified in the aorta between the aortic valve and the descending aorta at the level of the diaphragm in 29 infants. Eight had a PDA determined by echocardiography. Three methods were used to assess PWV; delay between the arrival time, time of maximum gradient and time of peak flow of the 2 flow curves. No significant difference in PWV between control and PDA infants was found.

Davi Marco Lyra-Leite¹, and Joao L. A. Carvalho^1
1Department of Electrical Engineering, University of Brasília, Brasília, Distrito Federal, Brazil

Fourier velocity encoding (FVE) eliminates partial volume effects that are an issue in phase-contrast imaging, and may be useful in the assessment of valvular disease and of carotid wall shear stress. Although the scan-time of 2DFT FVE is prohibitively long, the spiral FVE method is substantially faster. The temporal resolution of temporally-accelerated spiral FVE can be improved if spatial aliasing due to undersampling is reduced. This may be achieved using parallel imaging. We investigate the use of the SPIRiT method to accelerate spiral FVE acquisition. We show that SPIRiT is able to completely remove spatial aliasing from the undersampled time-velocity distributions.

Rosana Ribeiro Lima¹, and Joao L. A. Carvalho^1
1Department of Electrical Engineering, University of Brasília, Brasília, DF, Brazil

Fourier velocity encoding (FVE) may be useful in the assessment of valvular disease and of carotid wall shear stress, as it eliminates partial volume effects that are an issue in phase-contrast imaging. The scan-time of 2DFT FVE is prohibitively long for clinical use, but the spiral FVE method is substantially faster. FVE can be significantly accelerated using compressed sensing. However, iterative reconstruction of spiral FVE is time-consuming, because of non-Cartesian sampling and multidimensionality. The sequential implementation of reconstruction algorithms underuses the total capacity of multicore processors. We demonstrate a reduction of reconstruction time of spiral FVE data through parallel programming.

Marijn P Rolf¹, Mark BM Hofman¹, Joost PA Kuijer¹, Rob J van der Geest², Aernout M Beek³, Albert C van Rossum³, and Rudolf M Verdaasdonk^1
1Physics and Medical Technology, ICaR-VU, VU University Medical Center, Amsterdam, Netherlands, ²Radiology, Leiden University Medical Center, Leiden, Netherlands, ³Cardiology, ICaR-VU, VU University Medical Center, Amsterdam, Netherlands

The feasibility of a new 7D PC-SSFP sequence for mitral regurgitation volume quantification is assessed. The 7D PC-SSFP sequence implementation is based on a balanced SSFP gradient scheme with velocity encoding. Mitral volume flow was determined in ten healthy subjects and in two patients with mitral insufficiency. It was measured directly at the mitral valve using 7D PC-GE and 7D PC-SSFP, and indirectly using aorta flow and left ventricular volumes. Images showed reasonable quality, although occasional respiratory motion artifacts were noted. Regurgitation volumes in healthy subjects were not significantly different from zero and a clear regurgitation was observed in both patients.

Octavia Biris^1,2, Sanjiv J Shah³, Michael J Cuttica⁴, Jeremy D Collins¹, James C Carr¹, and Timothy J Carroll^1
1Radiology, Northwestern University, Chicago, IL, United States, ²Biomedical Engineering, Northwestern University, Evanston, IL, United States, ³Feinberg School of Medicine/Cardiology, Northwestern University, Chicago, IL, United States, ⁴Feinberg School of Medicine/Pulmonary and Critical Care, Northwestern University, Chicago, IL, United States

We show proof-of-principle quantification of pulmonary artery pressure wave forms in patients with pulmonary arterial hypertension, by a three element Windkessel model with phase contrast MRI flow, MRI measured compliance, vascular resistance, characteristic impedance and mean pulmonary arterial pressure as inputs. To increase the resolution of the systolic pressure, we up-sample the flow input to a desired temporal resolution, by Fourier deconvolution with a boxcar function. The pressure wave forms obtained from the three element Windkessel and the up-sampled flow wave form are compared to pressure wave forms obtained by the two element Windkessel, with no re-sampling of flow data.

Pablo Bächler¹, Natalia Pinochet¹, Israel Valverde², Sarah Nordmeyer³, Titus Kuehne³, Gerard Crelier⁴, Claudia Prieto¹, Cristian Tejos¹, Pablo Irarrazaval¹, and Sergio Uribe^1
1Pontificia Universidad Católica de Chile, Santiago, Chile, ²King's College London, London, United Kingdom, ³Deutsches Herzzentrum Berlin, Berlin, Germany, ⁴ETH and University of Zurich, Zurich, Switzerland

Measuring the caval contribution to flow in the Right and Left Pulmonary Artery of Fontan patients is of great interest, because uneven flow distribution might lead to Pulmonary Arteriovenous Malformations (PAVMs) decreasing systemic oxygenation. However, quantify the flow distribution with standard methods is difficult when more than one vessel contributes with blood flow, such as in the pulmonary arteries of Fontan patients. We validated a new method to calculate caval contribution based on particles traces from 4D flow data. This method may identify Fontan patients at risk for developing complications secondary to uneven caval flow distribution, such as PAVMs.

Maximilian Frederik Russe¹, Philipp Blanke¹, Wulf Euringer¹, Julia Geiger¹, Zoran Stankovic¹, Bernd Jung¹, and Mathias Langer^1
1Diagnostic Radiology - Medical Physics, University Hospital, Freiburg, Germany

Blood flow patterns are altered in aortic aneurysms. After endovascular aortic repair (EVAR), changes in flow patterns are conceivable, potentially resulting in stent-specific complications such as iliac limb thrombosis due to functional stenosis or proximal neck dilation. Using flow-sensitive MRI and flow visualization, flow patterns were studied in vivo prior and after EVAR. While pre-EVAR aortic blood flow patterns were characterized by vortex-formation and flow deceleration during passage through the aneurysm, post-EVAR blood flow was laminar with similar velocities in the stent body and the aorta proximal to the stent, but with strongly increased velocities in the iliac limbs.

Marcus T. Alley¹, Albert Hsiao¹, and Shreyas S. Vasanawala^1
1Radiology, Stanford University, Stanford, CA, United States

Time-resolved 3-dimensional phase-contrast MR imaging (4D-PC MRI) is typically subject to respiration artifacts that can limit anatomic visualization. Navigator gating and respiratory compensation can be used but result in even longer scan times. Because the lipid signal is very bright and tends to originate from close to the chest wall, we hypothesize that the elimination of this signal will reduce the severity of the resulting respiration artifacts. Here we demonstrate that the inclusion of an intermittent fat saturation pulse in a Cartesian 4D-PC acquisition can reduce the artifact severity and improve vascular visualization with no acquisition time penalty.

Julio Sotelo^1,2, Pablo Bächler^2,3, Steren Chabert^1,2, Claudia Prieto^2,4, Daniel Hurtado⁵, Pablo Irarrázaval^2,4, Cristian Tejos^2,4, and Sergio Uribe^2,6
1Biomedical Engineering Department, Faculty of Biological Science, Universidad de Valparaíso, Valparaíso, Chile, ²Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, ³School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁴Electrical Engineering Department, Faculty of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁵Structural Engineering Department, Faculty of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁶Radiology Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile

In this work we proposed a novel and reproducible method to calculate WSS derived from 4D flow data, in the main pulmonary artery (PA), right PA (RPA) and left PA (LPA), of volunteers and patients with Congenital Heart Diseases (CHD). In volunteers we found a greater WSS in the RPA compared with the LPA, which is probably associated with helical flow pattern in the RPA. Values of WSS obtained in patients with CHD showed increasing values and great variability of WSS. In conclusion, this method may be helpful to identify patient with CHD at risk of developing Pulmonary Arterial Hypertension.

Julio Garcia¹, Lyes Kadem², Eric Larose¹, and Philippe Pibarot^1
1Medicine, Laval University, Quebec, Quebec, Canada, ²Concordia University, Montreal, Quebec, Canada

Valvulo arterial impedance (ZVA) is an independent and powerful predictor of poor outcome for patients with aortic stenosis (AS) severity, it is usually computed from transthoracic echocardiography (TTE) measurements. However, there are often discrepancies among the TTE measurements. Cardiovascular magnetic resonance (CMR) may be used to corroborate stenosis severity by computing effective orifice area (EOA), mean pressure gradient (MPG) and ZVA. The aim of this study is to examine the agreement of TTE and CMR for the estimation of EOA, MPG and ZVA in patients with AS. ZVA CMR using corrected MPG had a good concordance with ZVA TTE and was a good predictor of patient outcome after one year follow.

Hung-Hsuan Wang¹, and Hsu-Hsia Peng^2
1National Tsing Hua University, Hsinchu, Taiwan, ²National Tsing Hua University, Taiwan

Pulmonary arterial hypertension (PAH) is one of the five categories of pulmonary hypertension (PH). In previous study, hemodynamic parameters of patients with PH, measured by non-invasive phase-contrast magnetic resonance imaging (PC-MRI) and invasive catheterization methods, have been proved with high correlation coefficients. In this study, we aim to acquire windkessel volume (V_wk), acceleration time (T_acce), acceleration volume (V_acce), and other hemodynamic parameters to investigate differences between normal subjects and patients with PAH. Student¡¦s t-test was used to comprehend the significance of the difference between normal subjects and PAH patients.

Holger Eggers¹, Liesbeth Geerts-Ossevoort², Evert-Jan Vonken³, and Tim Leiner^3
1Philips Research, Hamburg, Germany, ²Philips Healthcare, Best, Netherlands, ³University Medical Center Utrecht, Utrecht, Netherlands

A flexible dual-echo Dixon method was recently demonstrated to permit first-past contrast-enhanced peripheral angiography without subtraction. In this work, the feasibility of replacing it by a single-echo Dixon method is studied. Fat-suppressed images were reconstructed from dual-echo acquisitions in patients, once separately from the first and the second echo with a single-echo Dixon method and once from both echoes with a dual-echo Dixon method. While single-echo acquisitions promise to decrease scan time or increase spatial resolution, they prove to be more prone to flow and swapping artifacts and more sensitive to the choice of echo time(s).

Guenther Schneider¹, Arno Buecker¹, Alexander Massmann¹, and Peter Fries^1
1Diagnostic and Interventional Radiology, Saarland University Hospital, Homburg, Germany

Purpose of our study was to evaluate CE-MRA for management of pulmonary arterio-venous malformations (PAVM) in patients with hereditary hemorrhagic telangiectasia (HHT). 286 patients (mean-age 45,9 y, male/female = 118/168) with confirmed HHT or first degree relatives underwent screening pulmonary CE-MRA (MultiHance 0.1 mmol/kg bodyweight). Patients with relevant PAVM were referred for DSA. CE-MRA detected 323 PAVM in 97 patients. 74 patients with 263 PAVMs detected on CE-MRA underwent DSA. Significantly fewer PAVMs (205/263 [78%]) were demonstrated on global DSA of which 191 were embolized. Follow-up CE-MRA showed 57 newly developed PAVM in 14 patients (interval 1-6years) and 32 reperfused PAVM in 24 patients (interval 3months-7years). All reperfused PAVMs were confirmed by DSA and reembolized successfully. CE-MRA can be considered method of choice for management of PAVMs in HHT.

Jesse Habets¹, Herman J.A. Zandvoort², Sandra A. Cornelissen^1,3, Frans L. Moll², L. Wilbert Bartels³, Joost A. van Herwaarden², and Tim Leiner^1
1Radiology, University Medical Center Utrecht, Utrecht, Netherlands, ²Vascular Surgery, University Medical Center Utrecht, Utrecht, Netherlands, ³Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands

Endovascular repair for abdominal aortic aneurysm (EVAR) requires life-long postoperative imaging follow-up to detect complications. Prior work has shown that MRI with a blood pool agent with 85% albumin binding is more sensitive than CTA for endoleak detection, especially for slow flow and type II endoleaks. This work found that a gadolinium contrast agent with just 5% albumin binding is highly sensitive for the detection of endoleaks in patients with AAA growth and no or uncertain endoleak on CT angiography.

Rajkumar Yarlagadda¹, Mark L Schiebler¹, Scott B Reeder^1,2, Christopher J Francois¹, Thomas M Grist¹, and Scott K Nagle^1,2
1Radiology, University of Wisconsin, Madison, WI, United States, ²Medical Physics, University of Wisconsin, Madison, WI

The largest study to date comparing MRA with CTA for diagnosis of pulmonary embolism (PIOPED III) reported a high technical failure rate of 25% (11-51%) across participating centers. Technical developments since that study have significantly improved the quality of clinical PE MRA examinations. We report here the results of a retrospective image quality evaluation of a high-volume clinical PE MRA practice and suggest the key technical developments that have resulted in greatly improved performance.

Zhan Xu¹, Marina Emborg^2,3, Do Tromp¹, Nagesh Adluru¹, Martin Brady⁴, Raghu Raghavan⁴, Ken Kubota⁵, and Andrew L Alexander^1,6
1Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin Madison, Madison, WI, United States, ²Department of Medical Physics, University of Wisconsin Madison, Madison, WI, United States, ³Wisconsin National Primate Research Center, ⁴Therataxis,LLC, Baltimore, MD, ⁵Kinetics Foundation, Los Altos, CA, United States, ⁶Department of Medical Physics and Psychiatry, University of Wisconsin Madison, Madison, WI, United States

In our CED research on rhesus macaque monkeys for treatment of Parkinson's disease, the location of infusion spot within brain highly determines the effect of the delivered drug. We generate a probabilistic MRA template of putamen on both hemispheres. By overlaying the template with T1W template, which is generated by another member of our group with identical subjects, we find out blood vessels mainly locate in lateral surface of putamen, there is barely any vessel within. Also a high probability region is found in this MRA template, where we should avoid during infusion in any future subject

Constantine Raptis¹, Sanjeev Bhalla², Kathryn Fowler², Vamsi Narra², Rex Parker², Priatna Agus³, and Pamela Woodard^2
1Diagnostic Radiology - Cardiothoracic Imaging Section, Mallinckrodt Institute of Radiology, St. Louis, MO, United States, ²Mallinckrodt Institute of Radiology,³Siemens

Pulmonary MRA examinations for pulmonary embolism are often subject to technically inadequate images, with breathing artifact as a particularly important problem. Blood pool contrast agent enhanced free breathing radial VIBE sequences can be used in pulmonary MRA protocols for pulmonary embolism as an adjunct to traditional GRE sequences, and can be of particular value in patients with dyspnea. We present our initial experience with radial VIBE sequences in pulmonary MRA, including SNR and CNR, as well as comparison with other MRI sequences and computed tomography.

Anne Kirchherr¹, Danielle Franke¹, Detlef Stiller², and Andreas Briel^1
1nanoPET Pharma GmbH, Berlin, Germany, ²In-Vivo Imaging, Target Discovery Research, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany

In the present work a blood pool contrast agent (CA) composed of Gd-DTPA conjugated to a biodegradable polymer was synthesized and characterized. The CA showed high contrast efficiency with 2 - 3 times higher relaxivities compared to conventional contrast agents. In vivo experiments in mice showed that the CA remained within the vascular system for a prolonged period of time compared to Gd-DTPA and that it was cleared from the blood through renal excretion with a half-life of 1.9 h. The novel contrast agent can be of use in magnetic resonance angiography and in studies of renal structure and function.

Pan-Ki Kim^1,2, Bong-sik Jeon³, Young Ho So⁴, Eung-Gyu Kim³, and Whal Lee^2,5
1Kwangwoon University, Seoul, Korea, ²SNU-Duke Cardiovascular MR Research Center, Seoul, Korea, ³Nano R&D Group, Hanwha Chemical, Daejeon, Korea,⁴Radiology, Seoul National University Boramae Medical Center, Seoul, Korea, ⁵Radiology, Seoul National University Hospital, Seoul, Korea

Extremely small-sized iron oxide nanoparticles (ESION) recently developed an iron oxide based contrast agent was made of 3 nm-sized nanoparticle. Because of small size iron oxide nanoparticles, ESION has low r2/r1 ratio and long blood circulation time, unlike existing superparamagnetic iron oxide nanoparticles (SPIO), and that can be utilized as T1 contrast agent like a gadolinium based one without nephrogenic system fibrosis. This study was carried out to evaluate whether ESION is clinically useful through the animal study that acquired first-pass MR image and high spatial resolution 3D MR angiograph at steady-state to compare with gadolinium based contrast agent (Gd-DOTA).

Ioannis Koktzoglou¹, NavYash Gupta^2,3, and Robert R Edelman^1
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, ²Vascular Surgery, NorthShore University HealthSystem, Evanston, IL, United States, ³The University of Chicago Pritzker School of Medicine, Chicago, IL, United States

Pseudo-continuous arterial spin-labeled (pCASL) carotid MR angiography provides excellent arterial-to background contrast but may produce artifacts in patients who move or swallow during the exam. The aim of this work was to describe a self-configuring and hybrid pseudo-continuous and pulsed spin labeling preparation that incorporates background suppression to reduce motion-related artifacts as well as improve vascular contrast-to-noise ratio in pCASL-based carotid MRA.

Hattie Zhi Chen Dong¹, Shreyas S. Vasanawala², and Dwight G. Nishimura^1
1Electrical Engineering, Stanford University, Stanford, CA, United States, ²Radiology, Stanford University, Stanford, CA, United States

Multiple inversion recovery (MIR) preparation combined with alternating TR balanced SSFP is a promising technique for rapid non-contrast-enhanced renal angiography. MIR MRA achieves a high level of background suppression while allowing for flexible selection of inflow times. In this work, we explore practical factors to improve image quality, and demonstrate scans at various orientations and increasing levels of detail. Each image was acquired in one heartbeat, which is highly advantageous for respiratory artifact mitigation and real-time interactive assessment.

Songlin Yu¹, Lirong Yan², Yuqiang Yao³, Shuo Wang⁴, Mingqi Yang⁴, Bo Wang⁵, Yan Zhuo⁵, Lin Ai⁶, Xinyuan Miao⁵, Jizong Zhao⁴, and Danny J. J. Wang^2
1Beijing Tiantan Hospital, Capital Medical University, beijing, beijing, China, ²Department of Neurology University of California Los Angeles Ahmanson-Lovelace Brain Mapping Center, ³Beijing Jishuitan Hospital, Peking university, ⁴Beijing Tiantan Hospital, Capital Medical University, ⁵The State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of, ⁶Beijing Neurosurgical institute

Digital subtraction angiography (DSA) remains the gold standard to diagnose intracranial arteriovenous malformations (AVMs) but is invasive. Existing MR angiography (MRA) is suboptimal for assessing the hemodynamics of AVMs. This study evaluated the clinical utility of a novel non-contrast 4D dynamic MRA (dMRA) in the evaluation of intracranial AVMs, through comparison with DSA and time-of-flight (TOF) MRA in 19 AVM patients. DMRA was able to detect 16 out of 19 AVMs, and the ratings of AVM size and location matched those of DSA. The hemodynamic information provided by dMRA improved diagnostic confidence scores by TOF MRA.

Andrew Nicholas Priest¹, Martin John Graves¹, and David John Lomas^1
1Department of Radiology, Addenbrookes Hospital and Cambridge University, Cambridge, United Kingdom

MRI has the potential for multi-contrast imaging of venous thrombo-embolism (VTE). Luminal imaging may be performed using ADVANCE-MRV, a recently developed method which relies on suppression of flowing signal using an iMSDE preparation module. It is demonstrated that signal suppression is governed both by the flow velocity and by velocity dispersion. In low-dispersion situations, the signal may oscillate as a function of velocity, leading to signal loss from the subtraction venograms. This effect is investigated in volunteers, and an image combination method is proposed, leading to more uniform vascular images despite flow variations.

Naoyuki Takei¹, Mitsuharu Miyoshi¹, Masayoshi Sugimura², Takayuki Masui², and Hiroyuki Kabasawa^1
1Global Applied Science Laboratory, GE Healthcare, Hino, Tokyo, Japan, ²Radiology, Seirei Hamamatsu General Hospital, Japan

The purpose of this study is to eliminate low and dark flow artifact at descending aorta encountered at 3.0T on 3D Balanced Steady State Free Precession (bSSFP) with slab selective inversion pulse for visualizing renal arteries.�@A novel trigger procedure is presented with triple triggers for achieving both carotid and respiratory synchronized data acquisition despite the use of long inversion pulse over 1 second. The comparison study was performed to conventional respiratory trigger alone sequence on 1.5T and 3.0T. Compared to the conventional respiratory trigger the advantage of the proposed approach is robust, uniform and high arterial blood visualization.

Andrew J Wheaton¹, Robert Anderson¹, and Mitsue Miyazaki^2
1Toshiba Medical Research Institute USA, Mayfield Village, OH, United States, ²Toshiba Medical Research Institute USA, Vernon Hills, IL, United States

Noncontrast-enhanced MRA using gated 3D FSE (FBI, NativeSPACE, Trance) relies on the inherent flow sensitivity of FSE. A dark blood image acquired during systole is subtracted from a bright blood image acquired during diastole. The flow sensitivity is a function of refocusing angle; high refocusing angles result in bright large arteries, but diminished branch arteries. The opposite is true for low refocusing angles. This study proposes a hybrid method using high refocusing angle in diastole and low refocusing angle in systole. The resultant angiogram contains bright blood in both small and large arteries with minimal increase in background signal.

Jana Hutter^1,2, Robert Grimm¹, Christoph Forman^1,2, Joachim Hornegger^1,2, and Peter Schmitt^3
1Pattern recognition lab, Universität Erlangen-Nürnberg, Erlangen, Germany, ²Erlangen graduate school in avanced optical technologies, Erlangen, Germany, ³MR Application & Workflow Development, Siemens AG, Healthcare Sector, Germany

Non-contrast enhanced 3D MR angiography of the renal arteries typically needs a long acquisition time. We use an iterative reconstruction algorithm which combines parallel MRI and compressed sensing to accelerate the acquisition time by a factor of up to 9. Different undersampling factors, realized with a dedicated pattern, are applied and reconstructed with our approach. The evaluation shows that a high level of image quality regarding sharpness and contrast in the first and second order branches as well as the maximal visible blood path length is achieved.

Ioannis Koktzoglou^1,2, NavYash Gupta^2,3, and Robert R Edelman^1
1Radiology, NorthShore University HealthSystem, Evanston, IL, United States, ²The University of Chicago Pritzker School of Medicine, Chicago, IL, United States,³Vascular Surgery, NorthShore University HealthSystem, Evanston, IL, United States

Pseudo-continuous arterial spin labeling (PCASL) has been reported to provide better signal to noise ratio than pulsed arterial spin labeling for carotid MR angiography. The purpose of this study was to determine the accuracy of PCASL MRA for quantifying carotid artery stenosis (CAS) in patients with sonographically documented CAS. Accuracy was assessed relative to conventional 3D TOF and contrast-enhanced MRA techniques.

Ung Jang¹, Yura Park¹, and Dosik Hwang^1
1School of Electrical and Electronic Engineering, Yonsei University, Seoul, Korea

The aim of this study is to acquire high-quality SWI-MRv at longer TE by reducing the noise of phase data on the temporal domain of 3D multi-echo datasets for obtaining high-SNR phase mask.

Daniel V Litwiller¹, Mahdi S Rahimi², Wei Sun³, Ananth J Madhuranthakam⁴, Dan W Rettmann¹, Frank R Korosec⁵, and Jean H Brittain^6
1Global Applied Science Laboratory, GE Healthcare, Rochester, MN, United States, ²Biomedical Engineering, University of Wisconsin, Madison, WI, United States,³MR Engineering, GE Healthcare, Waukesha, WI, United States, ⁴Global Applied Science Laboratory, GE Healthcare, Boston, MA, United States, ⁵Medical Physics and Radiology, University of Wisconsin, Madison, WI, United States, ⁶Global Applied Science Laboratory, GE Healthcare, Madison, WI, United States

Quiscent-Interval Single-Shot (QISS) is a recently developed non-constrast MR angiography technique that relies on a signal-saturation-based fat suppression pulse, which is sensitive to B₀ and B₁ inhomogeneities. In this work, we report a dual-echo bipolar QISS sequence, followed by a two-point Dixon fat-water reconstruction algorithm to synthesize fat-free, water-only images of arterial signal in the lower extremities, demonstrating robust and uniform fat suppression, improved vessel conspicuity and increased signal-to-noise ratio.

Mauricio S Galizia^1,2, Christopher Glielmi³, Ioannis Koktzoglou¹, Eugene Dunkle¹, James C Carr², and Robert R Edelman^1
1Department of Radiology, NorthShore University HealthSystem, Evanston, IL, United States, ²Department of Radiology, Northwestern University-Feinberg School of Medicine, Chicago, IL, United States, ³Cardiovascular MR R&D, Simens Healthcare, Chicago, IL, United States

Ten patients with peripheral arterial disease were imaged with nonenhanced quiescent-interval single-shot (QISS) MRA. Thinner slices were also acquired in the region of the knee. A blinded observer graded image quality in several vessel segments in the proximal calf. The horizontal anterior tibial, the posterior tibial, and the peroneal arteries had higher image quality scores in the thin-slice images. In the horizontal anterior tibial artery, the proportion of nondiagnostic and poor quality images was reduced from 50% to 5%. Acquiring additional thin slices in selected regions when imaging with QISS leads to better image quality and might improve diagnosis.

Sören Johst^1,2, Karsten H Wrede^1,3, Mark E Ladd^1,2, and Stefan Maderwald^1
1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, ²Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Germany, ³University Hospital Essen, Department of Neurosurgery, Germany

The visibility of the vasculature in TOF MRA highly profits from increased field strengths. The aim of this study was to create a clinical high-resolution 7T TOF MRA protocol with venous saturation, acquirable within a clinically acceptable measurement time. To ameliorate SAR restrictions, we used the VERSE algorithm for both excitation and saturation pulses. The use of standard 90° pulses for venous suppression generally leads to longer TR due to SAR limitations. For α Є [15°, 35°] and TR Є [20 ms, 35 ms], saturation flip angles of αSAT = (α + 15°) lead to acceptable venous saturation.

June Cheng-Baron¹, Kelvin Chow¹, Joseph J Pagano¹, D Ian Paterson², and Richard B Thompson^1
1Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada, ²Division of Cardiology, University of Alberta, Edmonton, Alberta, Canada

Current MRI methods used to measure left ventricular strain, including tissue tracking or phase-based methods, require onerous post-processing or specialty pulse sequences. We propose an alternative method for the determination of peak systolic global circumferential, longitudinal and radial strains that does not rely on tissue tracking and is based on basic SSFP cines and left ventricular volume analysis. The purpose of this study is to compare this new method to conventional tissue tagging-derived strains.

Abdallah G. Motaal¹, Rui Castro², Bram F. Coolen¹, Desiree Abdurachim¹, Jeanine Prompers¹, Luc Florack², Klaas Nicolay¹, and Gustav Strijkers^1
1Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands, ²Department of Mathematics and Computer Science, Eindhoven University of Technology, Eindhoven, Netherlands

Using low temporal resolution Cine CMR has a significant drawback in assessing the heart function, since the details of myocardial deformation go undetected. In this study we introduce the retrospective triggering acquisition scheme in combination with compressed sensing reconstruction to obtain very high frame Cine CMR in an acquisition time shorter than the time needed for a gold standard reconstruction. High acceleration factors were achieved without significant losses in image quality and derived cardiac functional parameters.

Haiyan Ding^1,2, Laura Fernandez-de-Manuel^1,3, Michael Schär^4,5, Elliot R. McVeigh¹, Henry Halperin⁶, M. Muz Zviman⁶, and Daniel A. Herzka^1
1Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, United States, ²Biomedical Engineering, Tsinghua University, Beijing, China, ³Biomedical Image Technologies Lab, ETSI Telecomunicacion, Universidad Politecnica de Madrid, and CIBER-BBN, Madrid, Spain, ⁴Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins School of Medicine, Baltimore, MD, United States, ⁵Philips Healthcare, Cleveland, Ohio, United States, ⁶Department of Medicine, Cardiology, Johns Hopkins School of Medicine, Baltimore, MD, United States

The area of myocardium at risk (AAR) is defined as hypoperfused myocardium at the time of an ischemic episode, such as acute myocardial infarction (MI). To assess AAR, measures of both scar and edema must be combined. Late Gadolinium enhancement (LGE) with phase sensitive inversion recovery (PSIR) is a well-established method of delineating scar. Recently, quantitative 3D T2 mapping has been shown to be a robust method for visualizing edema. In this work it is shown that the combination of 3D respiratory navigator gated T2 Mapping and PSIR make high-resolution whole-heart AAR determination possible.

Stefan Maderwald¹, Stephan Orzada^1,2, Sören Johst^1,2, Lena C. Schäfer^1,2, Anja Fischer^1,2, Thomas Schlosser², Mark E. Ladd^1,2, and Kai Nassenstein^1,2
1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, ²Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany

Real-time sequences for cardiovascular magnetic resonance (CMR) at ultrahigh field strengths (7 Tesla) could alleviate the need for a robust trigger signal, which fails in a large number of cases due to magneto-hydrodynamic effects. For signal transmission and reception a new custom-built 8 ch Tx / 24 ch Rx coil was used. The pulse sequence is based on a strongly undersampled radial FLASH sequence which is reconstructed with a sliding window approach. Cine-like images were acquired with a temporal resolution between 6 and 106 ms. Acceptable image quality was found for a temporal resolution of 49 ms per image.

Wolfgang Rehwald¹, Elizabeth Jenista², Deneen Spatz², Stephen Darty², Han Kim², Lowie Van Assche², Enn-Ling Chen², and Raymond Kim^2
1Siemens Healthcare, Chicago, IL, United States, ²Cardiology, Duke University, Durham, NC, United States

Common fat suppression techniques perform poorly in combination with phase sensitive inversion recovery (PSIR). We have developed a technique for fat suppression that results in black-fat PSIR images without additional SAR or acquisition time.

Sabrina Klix¹, Fabian Hezel¹, Jan Ruff², and Thoralf Niendorf^1,3
1Berlin Ultrahigh-Field Facility, Max-Delbrueck Center for Molecular Medicine, 13125 Berlin, Germany, ²Siemens Healthcare, 91054 Erlangen, Germany,³Experimental and Clinical Research Center (ECRC), Charité Campus Buch, Humboldt-University, 13125 Berlin, Germany

The anatomic MR imaging of the heart is mainly with black blood techniques. These techniques improve the segmentation of myocardium from the blood pool. For low-signal representation, a self calibrated split-echo FSE (SCSE-FSE) was proposed and implemented. The aim is to waive a separate reference scan, to shorten measurement times, enhances image quality and reduction of image artefacts. Clinically relevant short axis and four chamber view with double and triple inversion recovery images were acquired. The results of the SCSE-FSE technique by using a acceleration factors of up to R=4 compared with a conventional FSE are suitable for clinical applications.

Volker Herold¹, Thomas Kampf¹, Alexander Gotschy¹, Felix Breuer², Eberhard Rommel¹, Wolfgang Rudolf Bauer³, and Peter Michael Jakob^1
1Experimental Physics 5, University of Würzburg, Würzburg, Bavaria, Germany, ²Research Center for Magnetic Resonance Bavaria, ³Medizinische Universitätsklinik, University of Würzburg

Local elastic properties of the murine arteries such as the pulse-wave-velocity (PWV) can be calculated using PC-MRI to quantify blood-flow (Q) and cross-sectional area changes (A) (QA-method). To calculate the PWV the measured Q and A pulses have to undergo a frequency low pass filtering step. Moreover, a short total measurement time is of paramount interest, in particular with varying cardiac cycles. We present a method which substitutes temporal low pass filtering by temporal undersampled data acquisition followed by a k-t BLAST reconstruction with the benefit of an almost 10 fold acceleration of data acquisition without compromising the PWV calculation.

Valentina Taviani¹, Diego Hernando¹, Ann Shimakawa², Jean H. Brittain³, Kevin M. Johnson¹, Karl K. Vigen¹, and Scott B. Reeder^1,4
1Department of Radiology, University of Wisconsin, Madison, WI, United States, ²Global MR Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States, ³Applied Science Laboratory, GE Healthcare, Madison, WI, United States, ⁴Department of Medical Physics, University of Wisconsin, Madison, WI, United States

R₂* mapping in the heart is important to quantify myocardial iron concentration as well as for accurate water-fat separation. However, R₂* measurements in the myocardium are hampered by severe susceptibility variations due to the presence of tissue-air interfaces and deoxygenated blood in epicardial veins. In this work we propose a 3D free-breathing technique for water-fat separation and R₂* mapping in the heart and we compare our 3D free-breathing approach with a previously reported 2D breath-hold technique. Both phantom experiments and preliminary data in healthy volunteers showed that the 3D free-breathing technique greatly reduced susceptibility-induced variations in R₂*.

Tomasz Dawid Lindel¹, Andreas Greiser², Patrick Waxmann¹, Martin Dietterle¹, Frank Seifert¹, Ulrich Fontius², Wolfgang Renz², Matthias Alexander Dieringer^3,4, Tobias Frauenrath³, Jeanette Schulz-Menger⁴, Thoralf Niendorf^3,4, and Bernd Ittermann^1
1Physikalisch-Technische Bundesanstalt, Braunschweig & Berlin, Germany, ²Siemens AG Healthcare Sector, Erlangen, Germany, ³Berlin Ultrahighfield Facility (B.U.F.F.), Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany, ⁴Charité–Universitätsmedizin Berlin, Campus Buch, Experimental and Clinical Research Center (ECRC), Berlin, Germany

The feasibiltiy of cardiac MRI at 7T using a transmit array was demonstrated. A software solution was implemented for synchronizing the independent array CPUs with the cardiac trigger and CINE images were acquired with a modified product sequence for cardiovascular imaging. Using the 7T system in Tx array or single channel mode with hardwired phase settings produced identical image quality. In this proof-of-principle study the Tx array was used for static B₁ shimming only but the concept permits dynamic applications like transmit SENSE as well.

Holden H Wu^1,2, Joelle K Barral³, Dwight G Nishimura², and Michael V McConnell^1,2
1Cardiovascular Medicine, Stanford University, Stanford, CA, United States, ²Electrical Engineering, Stanford University, Stanford, CA, United States, ³HeartVista, Inc., Los Altos, CA, United States

Black-blood imaging is a crucial technique for visualizing the myocardium and studying the progression of atherosclerosis in the vessel wall. In this work, we present a new double inversion-recovery (DIR) black-blood imaging method based on the non-Cartesian 2D concentric rings trajectory, which requires half the number of readouts compared to 2D Cartesian encoding and supports 2D centric ordering to maximize the effectiveness of the DIR preparation. In addition, the concentric rings are acquired with a time-efficient multi-revolution design to enable fat/water separation for enhanced image contrast. Experimental results from cardiac and carotid imaging demonstrate the performance of this proposed technique.

Adrienne E Campbell^1,2, Anthony N Price³, Stephan Ellmerich⁴, Paul Simons⁴, Raya Al-Shawi⁴, Rupinder Ghatrora⁵, Tammy L Kalber⁵, Philip N Hawkins⁴, Roger J Ordidge⁶, James C Moon⁷, Mark B Pepys⁴, and Mark F Lythgoe^5
1Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, London, United Kingdom,²Department of Medical Physics and Bioengineering, University College London, London, United Kingdom, ³Robert Steiner MRI Unit, Imaging Sciences Department, Hammersmith Hospital, Imperial College London, London, United Kingdom, ⁴Wolfson Drug Discovery Unit, Centre for Amyloidosis and Acute Phase Proteins, Division of Medicine, University College London, London, United Kingdom, ⁵Centre for Advanced Biomedical Imaging, Division of Medicine and Institute of Child Health, University College London, London, United Kingdom, ⁶Centre for Neuroscience, University of Melbourne, Melbourne, Australia, ⁷Heart Hospital and Division of Medicine, University College London, London, United Kingdom

Equilibrium contrast MRI (EQ-MRI) was applied for the detection and monitoring of systemic amyloidosis in mice. Modest amyloid deposits in the heart were clearly detected by EQ-MRI even when cardiac function was not measureably impaired. An excellent discrimination between amyloidotic and control mice was observed in the liver where amyloid load is substantial. In addition, EQ-MRI was able to monitor the induction of amyloidosis and regression of amyloid deposits following the administration of a novel therapy, indicating the potential of this technique to monitor therapeutically induced amyloid regression.

Xiao Chen¹, Michael Salerno^2,3, Patrick F Antkowiak¹, and Frederick H Epstein^1,2
1Biomedical Engineering, University of Virginia, Charlottesville, VA, United States, ²Radiology, University of Virginia, Charlottesville, VA, United States, ³Cardiology, University of Virginia, Charlottesville, VA, United States

Many MR image series present temporal sparsity, in which image signal intensity changes smoothly through time, and such images are inherently suitable for acceleration using compressed sensing (CS) reconstruction. However, object motion between images violates temporal smoothness constraints and significantly degrades the quality of the CS-reconstructed images. To overcome this problem, we propose a general motion-guided CS algorithm which tracks object motion and guides the CS sparsity transform along the direction of motion. Improved image quality was observed using the proposed algorithm in dynamic contrast-enhanced images compared to non-motion guided reconstruction at an acceleration rate of 4.

Tomoe Barr¹, Chuan Huang², Aiden Abidov^3,4, Jaspreet Singh³, Bujji Ainapurapu³, Dipak KC³, Scott Squire⁴, Jean-Philippe Galons⁴, and Maria I Altbach^5
1Biomedical Engineering, University of Arizona, Tucson, AZ, United States, ²Mathematics, University of Arizona, United States, ³Medicine, University of Arizona, United States, ⁴Radiology, University of Arizona, United States, ⁵Radiology, University of Arizona, Tucson, AZ, United States

T2-weighted imaging is an important modality in cardiac MRI and has been used for the diagnosis of a series of pathologies. Recently, the importance of T2 mapping of the heart has been highlighted. In this work we present a double inversion radial fast spin-echo (DIR-RADFSE) technique combined with a principal component based reconstruction algorithm recently developed for T2 estimation. The method provides motion insensitivity and high spatial and temporal resolution data for the reconstruction of T2 maps from data acquired in a single breath hold.

Shane A Wells¹, Karl K Vigen¹, Jeffrey S Nackos¹, Scott B Reeder^1,2, and Diego Hernando^1
1Department of Radiology, University of Wisconsin-Madison, Madison, WI, United States, ²Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, United States

Excess myocardial iron can result in sudden death or heart failure, the leading causes of morbidity and mortality in transfusion-dependent thalassemia patients. Accurate and reproducible, non-invasive quantification of myocardial iron is important because effective chelation therapy can be initiated and cardiomyopathy averted. R2* mapping is very sensitive to the presence of tissue iron; however, in the myocardium, its broad use is limited due to macroscopic magnetic field inhomogeneities caused by susceptibility effects, most profound at the myocardial-air interface. The purpose of this work is to demonstrate the feasibility of a background magnetic field correction technique for more consistent R2* mapping.

Stefan Maderwald¹, Stephan Orzada^1,2, Lars Haering³, Andreas Czylwik³, Thomas Schlosser², Mark E. Ladd^1,2, and Kai Nassenstein^1,2
1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany, ²Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany, ³Department of Communication Systems, University Duisburg-Essen, Essen, Germany

In this study an in-house developed phonocardiogram (PCG) gating device was used to validate the diagnostic accuracy of acoustic triggered sequences in a clinical routine protocol at 1.5T. PCG- and ECG-gated cine imaging sequences for the assessment of LV global and regional function as well as velocity-encoded phase-contrast imaging sequences for flow quantification were compared. 147 consecutive patients were enrolled and evaluated. PCG-gated imaging was successful in 95%, ECG-gated in 100% of all patients. With cine imaging an excellent correlation between PCG and ECG was observed, whereas flow quantification measurements showed a wide limit of agreement for all variables analyzed.

Wei Zha¹, Steven Lloyd², Himanshu Gupta², Stanley J. Reeves¹, and Thomas S. Denney^1
1Auburn University, Auburn, AL, United States, ²University of Alabama at Birmingham

A fast dynamic imaging method is proposed to shorten the image acquisition. Only the dynamic region in an arbitrary shape that encloses the heart is reconstructed in each timeframe. All other pixels were reconstructed once for the whole image sequence. The phase-encoding direction alternated horizontally and vertically at even and odd timeframes for a more k- space coverage. The undersampling pattern for each timeframe is pre-calculated using a modified sequential backward selection method. Our earlier simulation shows that 40 resized image sequences from different subjects are able to be reconstructed using 44% of the k-t space data reliably and stably.

Hendrikus J.A. Crooijmans¹, Thomas Ruder^2,3, Sandra Mathier³, Michael Thali², and Oliver Bieri^1
1Department of Radiology and Nuclear Medicine, Division of Radiological Physics, University of Basel Hospital, Basel, Switzerland, ²Department of Medicine and Imaging, Institute of Forensic Medicine, University of Zürich, Zürich, Switzerland, ³Department of Medicine and Imaging, Institute of Forensic Medicine, University of Bern, Bern, Switzerland

Quantitative diffusion imaging using a dwDESS sequence is relaxation time independent. In contrast to other SSFP diffusion imaging methods it uses both primary echo paths. Both direction dependent and direction independent diffusion maps can be generated from dwDESS acquisitions. By means of a procine heart, we have shown that this method can be used to indicate fiber direction within the myocardium. Next to this, we have shown that with dwDESS imaging, it is possible to differentiate between older and acute myocardial infacts in a human post mortem case.

James W Goldfarb^1,2
1Research and Education, St Francis Hospital, Roslyn, New York, United States, ²Biomedical Engineering, SUNY Stony Brook, Stony Brook, NY, United States

Phantom experiments across a range of T1-values and heart rates demonstrated an underestimation of longer T1-values at higher heart rates using the conventional MOLLI curve fitting equation. A new fitting equation which includes the effect of incomplete magnetization recovery between inversion pulses provided a significantly better fit to the data and consistent estimates of T1-relaxation times over a range of heart-rates. Measurements in 15 subjects showed a heart rate dependence of T1-estimates of blood in the LV cavity. The new equation provided a significantly better fit (p<0.001) for both myocardial and LV blood T1-estimates without heart rate dependence.

Jing Liu¹, Petter Dyverfeldt¹, Michael Hope¹, and David Saloner^1
1University of California San Francisco, San Francisco, CA, United States

In this study, different undersampling patterns were used to accelerate phase-contrast imaging. Our preliminary results of aorta flow imaging have shown that radial like pattern on Cartesian grid is simple to implement and less sensitive to undersampling artifacts. Image reconstruction with compressed sensing provides good image quality and accurate flow measurements.

Sarah Anne Peel¹, Aruna Arujuna¹, James Harrison¹, Reza Razavi¹, Kawal Rhode¹, Jaswinder Gill¹, Tobias Schaeffter¹, and Rene Botnar^1
1Division of Imaging Sciences and Biomedical Engineering, King's College London, The Rayne Institute, London, United Kingdom

A good correlation has been found between late gadolinium enhancement using the inversion recovery (IR) pre-pulse and the outcome of radiofrequency ablation for atrial fibrillation. However, scar visualization is hampered by strong residual blood signal. Therefore imaging is often performed 25 minutes after contrast administration to ensure the contrast agent has cleared from blood. In this study, we found that the dual-IR pre-pulse achieved superior blood suppression at an earlier time point compared to the IR pre-pulse and without the need for a Look Locker scan. It can potentially improve scar visualization and reduce total scan time.

Christian Bock¹, Faruk Dogan¹, and Hans O. Pörtner^1
1Alfred-Wegener-Institute for Polar and Marine Research, Bremerhaven, Germany

Real-time cardiac MRI together with velocity mapping for blood flow quantification in different arteries were applied to study the cardiovascular performance of the marine crustacean Cancer pagurus, an animal model with a natural cardiovascular disorder. The feasibility of MRI for future monitoring of heart functioning and blood flow in a marine crustacean under conditions of ocean warming and acidification could be shown. Real-time cardiac MRI revealed an increase in heart function under conditions of ocean acidification as expected by the end of this century, whereas almost no increase in blood flow of the main arteries could be observed.

Christopher Nguyen^1,2, Zhaoyang Fan², Rohan Dharmakumar², Troy LaBounty³, James Min³, Daniel Berman³, and Debiao Li^2,4
1Biomedical Engineering Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA, United States, ²Departments of Biomedical Sciences and Imaging, Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States, ³Cedars-Sinai Medical Center, Los Angeles, CA, United States, ⁴Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States

Cardiac diffusion MRI (CDMRI) has the potential to identify acute myocardium ischemia and assess the chronic change of myofiber orientation after a myocardial infraction. Serious technical challenges such as cardiac motion and clinical hardware limitations restrict the technique in vivo. We propose a novel application of DW driven equilibrium balanced steady-state free precession (DW-DE-bSSFP) to include second order MOCO (SOMOCO) that not only allows for longer Tdiff and acceptable b-values, but also takes advantage of the high SNR of bSSFP. We show the feasibility of applying SOMOCO-DW-DE-bSSFP for in vivo CDMRI within clinically human limited MR parameters in healthy volunteers.

Matthias Alexander Dieringer^1,2, Thiago de Quadros^1,2, Jan Hentschel¹, Werner Hoffmann³, Thoralf Niendorf^1,2, and Jeanette Schulz-Menger^1,2
1Berlin Ultrahigh Field Facility, Max-Delbrueck Center for Molecular Medicine, Berlin, Germany, ²Experimental and Clinical Research Center (ECRC), Charité Campus Buch, Humboldt-University, Berlin, Germany, ³Metrology in Medicine, Physikalisch-Technische Bundesanstalt, Berlin, Germany

The development and validation of MR sequences require a high degree of reproducibility including phantom experiments that mimic in vivo. This study demonstrates the design, implementation, application and evaluation of a comprehensive left ventricle model. The model is designed to resemble motion patterns and flow dynamics of a beating heart, as well as signal characteristics and relaxation times of myocardial tissue.

Huijun Chen¹, Jinnan Wang², Chun Yuan¹, and William S Kerwin^1
1University of Washington, Seattle, WA, United States, ²Philips Research North America, United States

Phase-Sensitive Inversion Recovery (PSIR) has been widely used in cardiac imaging to detect infarcts by providing consistent high contrast between infarcts and normal myocardium. Recently, it has been shown as an improved intraplaque hemorrhage detection tool with good blood suppression and as a possible MRA tool in carotid atherosclerosis imaging. However, considerable amount of reconstruction artifacts can be found in PSIR sequence acquired short Inversion Time (TI). In this abstract, we sought to analyze the cause of these artifacts and propose a solution.

Jeremy R McGarvey^1,2, Kevin J Koomalsingh^1,2, Norihiro Kondo², Manabu Takebe², Walter R.T. Witschey^2,3, Gerald A. Zsido², Christen M. Dillard², Kristina Lau², Gabrielle Pilla², Joseph H. Gorman^1,2, Robert C. Gorman^1,2, and James J. Pilla^2,3
1Department of Surgery, University of Pennsylvania Health System, Philadelphia, PA, United States, ²Gorman Cardiovascular Research Lab, Harrison Department of Surgical Research, Glenolden, PA, United States, ³Department of Radiology, University of Pennsylvania Health System, Philadelphia, PA, United States

Treatment of ischemic cardiomyopathy remains a complex clinical problem. We have developed an novel MRI-safe left ventricular assist device which is able to apply directed and synchronized force to an infarct area. In vivo cardiac MRI was utilized to evaluate left ventricular function and geometry after device implantation in a porcine ischemic heart failure model. SGFP cine sequences demonstrated a significant increase in ejection fraction and stroke volume while using the synchronized pulsation device when compared to the unassisted ventricle. As such, MRI was effectively used to quantify and characterize ventricular function using a novel mechanical ventricular assist device.

Glenn S. Slavin¹, Maureen N. Hood², Vincent B. Ho², and Jeffrey A. Stainsby^3
1GE Healthcare, Bethesda, MD, United States, ²Walter Reed National Military Medical Center, Bethesda, MD, United States, ³GE Healthcare, Toronto, ON, Canada

The challenge for cardiac T1 mapping is obtaining sufficient sampling of the T1 relaxation curve in a single breath-hold. Traditional single-point inversion recovery is limited by short delay times and is not feasible in a breath-hold. Multi-point (Look-Locker) inversion recovery is possible in a breath-hold; however, it necessitates both partial Fourier and parallel imaging and long data acquisition windows. Look-Locker imaging also measures “apparent” relaxation times (T1*), rather than true T1. This work demonstrates a cardiac T1 mapping method that measures true T1 in a single breath-hold using multiple single-point saturation recovery with delay times longer than the cardiac cycle.

Sarah Anne Peel¹, Aruna Arujuna¹, Reza Razavi¹, Kawal Rhode¹, Jaswinder Gill¹, Tobias Schaeffter¹, and Rene Botnar^1
1Division of Imaging Sciences and Biomedical Engineering, King's College London, The Rayne Institute, London, United Kingdom

Pulmonary vein isolation using RF ablation is an established treatment for patients with atrial fibrillation. Late gadolinium enhancement (LGE) imaging can be performed acutely after ablation using the inversion recovery (IR) pre-pulse. However, the IR pre-pulse generates high signal from areas of oedema as well as contrast uptake. In this study, we showed that the dual-IR pre-pulse only generates high signal from areas of contrast uptake whilst suppressing the signal from fluid and normal atrial wall. This may help differentiate contrast uptake from oedema in LGE imaging to visualize acute damage caused by RF ablation.

Michael Loecher¹, Steven Kecskemeti², Kevin M Johnson¹, Patrick Turski³, and Oliver Wieben^1,3
1Medical Physics, University of Wisconsin Madison, Madison, WI, United States, ²Physics, University of Wisconsin Madison, Madison, WI, United States, ³Radiology, University of Wisconsin Madison, Madison, WI, United States

This study investigates the performance of a finite difference method and a radial basis function algorithm for removing divergence from 4D-flow images. Noise reduction and visualization improvements are compared in a phantom and in vivo by comparing RMSE, noise levels, and streamline lengths. Overall the RBF method performs better, generally reducing noise by around 25% and improving streamline length by around 22%.

Sohae Chung¹, and Leon Axel^1
1Center for Biomedical Imaging, Radiology Department, NYU Langone Medical Center, New York, NY, United States

To obtain first-pass cardiac perfusion images, a saturation-recovery preparation with TurboFLASH readout can be used to capture the contrast enhancement dynamics. However, when using a SR preparation, non-uniform k-space data weighting in the phase-encoding direction, due to data acquisition during the transition toward the steady state, can lead to a filtering effect. This may lead to systematic overestimation of the image-derived arterial input function (AIF), with a resulting bias in the perfusion calculations. In this work, numerical simulations were used to correct for non-uniform k-space data weighting effects on the AIF.

El-Sayed H Ibrahim¹, Shannon Birchell², and Sherif Elfayoumy^2
1Department of Radiology, University of Florida, Jacksonville, FL, United States, ²School of Computing, University of North Florida, Jacksonville, FL, United States

Manual segmentation of MRI images is inefficient and inconsistent method for measuring ventricular volumes. In this study, new artificial intelligence technique (ISITOAA) is developed and implemented for measuring ventricular volumes. The technique is based on automatic delineation of blood-myocardium border using ant colony optimization with salient isolated thresholding. The technique was implemented on datasets from eight volunteers and the results were compared to manual segmentation. ISITOAA provided both left and right ventricular segmentation in single processing, and provided stability measure of the solution. ISITOAA showed good agreement with the gold standard and was faster and more consistent than manual segmentation.

Chun G Schiros¹, Himanshu Gupta², Steven G. Lloyd², Louis J Dell'Italia², and Thomas S Denney Jr.^1
1Auburn University, Auburn, AL, United States, ²University of Alabama at Birmingham

Approaches for quantifying cardiac function and geometry from cine MRI remain problematic because 1) systolic translocation of the right ventricular (RV) atrio-ventricular annulus is greater than that of the left ventricle (LV), resulting in unequal LV and RV stroke volumes and 2) surface models for measuring ventricular curvatures are usually based on coordinate systems with singularities at the ventricular apexes and assume a circular symmetry that is not applicable in the complex RV. To address these issues, a novel biventricular active mesh model is presented and validated in normal subjects, patients with mitral regurgitation and patients with pulmonary hypertension.

Erol Yeniaras¹, Jason R. Stafford¹, John D. Hazle¹, and Nikolaos V. Tsekos^2
1MD Anderson Cancer Center, Houston, Texas, United States, ²Medical Robotics Lab., University of Houston, Houston, Texas, United States

In this work we evaluate the viability of our computational methodology for MR guidance in minimally invasive cardio-thoracic interventions, particularly transapical aortic valve replacement in beating heart. Our system includes the dedicated software modules that operate synergistically for both processing real-time MR images and adjusting on-the-fly the acquisition parameters of scanner to better suit the particular conditions of interventions as they evolve. To verify the efficacy of the approach, safe access to aortic valve annulus via a small incision at the apex of the heart was simulated for 15 subjects.

Anja Hennemuth¹, Andreas Mahnken², Ola Friman³, Markus Huellebrand⁴, and Heinz-Otto Peitgen^4
1Fraunhofer MEVIS, Bremen, Bremen, Germany, ²Department of Diagnostic and Interventional Radiology, University Hospital Aachen, Aachen, Germany, ³Swedish Defence Research Agency, Linkoeping, Sweden, ⁴Fraunhofer MEVIS, Bremen, Germany

Late enhancement (LE) imaging has become the gold standard for detecting necrotic tissue with MRI. The underlying effect of contrast agent accumulation in defective tissue is observed in CT image data as well. The purpose of this work was the comparison of semi-automatically detected LE volumes from CT and MRI data of pigs with inflicted infarctions. Image data was analyzed with a method that combines a mixture model approach and an additional closing step for the inclusion of microvascular obstructions. The comparison of the results regarding location and volume of the segmented regions showed a good agreement.

Elizabeth J Nett¹, Jie Nguyen², Kevin M Johnson¹, Oliver Wieben^1,2, and Christopher J Francois^2
1Medical Physics, University of Wisconsin, Madison, Wisconsin, United States, ²Radiology, University of Wisconsin, Madison, Wisconsin, United States

In this study, we demonstrated the feasibility of noninvasively quantifying stenosis grade and pressure differences in congential heart disease patients with aortic coarctations or pulmonary artery stenosis using a radially undersampled 4D PC-MRI sequence. Anatomical measurements were compared with CE-MRA and pressure measurements were compared with Doppler ultrasound.

Prashanth Palaniappan¹, Orlando P. Simonetti^2,3, Yu Ding², Rizwan Ahmad², Hui Xue⁴, Ti-chuin Chang⁴, and Christoph Guetter^5
1Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio, United States, ²Davis Heart and Lung Research Institute, The Ohio State University, Columbus, Ohio, United States, ³Department of Radiology, The Ohio State University, Columbus, Ohio, United States, ⁴Siemens Corporate Research, United States, ⁵Siemens Corporate Research

In our current study, we propose a novel approach to de-noise Real-time (RT) cardiac cine images by combining two well established algorithms: Temporal Karhunen-Loeve Transform (KLT) and Spatial Wavelet Filtering. The combined KLT+wavelet approach is very effective in enhancing image Signal-to-Noise ratio (SNR) while preserving the edge sharpness of the image. This is a fully automatic method that does not require estimation or user selection of any free parameters, nor acquisition of training data. In rate 6 real-time cine images, the proposed approach showed superiority to the 3D wavelet filter in terms of image SNR and edge sharpness. The performance of the proposed approach also increased with increasing frame length.

Hui Wang¹, Mo Kadbi¹, Melanie Troughber², and Amir Amini^1
1University of Louisville, Louisville, KY, United States, ²Philips Medical Systems, Cleveland, Oh, United States

Tagged MRI has been an excellent technique for measuring myocardial deformations and cardiac mechanical functions since its development in the late 1980s. In data processing, a number of approaches have been proposed in recent years. Among all, frequency-based methods have become more widely popular for analysis of myocardial displacements . In particular, the SimMod has the following distinct advantages over HARP analysis which has become popular for frequency domain analysis of tagged images. Bandpass filtering the off-center peak of tagged image spectrum is a critical step for accurate recovery of the cardiac motion with SinMod. In this abstract, we compared the performance of three different types of bandpass filters in analyzing myocardial deformation using the SinMod method.

Yu Ding¹, Hui Xue², Ti-chiun Chang², Christoph Guetter², and Orlando Simonetti^1,3
1Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States, ²Siemens Corporate Research, ³Biomedical Engineering, The Ohio State University

Compared to real-time cardiac cine images at rest, the exercise stress real-time cine images show significantly lower SNR. In this abstract, we will demonstrate that the excess high noise level is a motion induced noise. When the motion is severe, every temporal frame cannot be approximated as an instantaneous “snap-shot”. The motion may induce a signal variation which behaves statistically like spatial noise. Using in vivo volunteer study, we found that the apparent noise level in stress MRI raw data with rapid heart rate and breathing is higher than that of the resting real-time cine raw data.

Lei Xu^1,2, Jun Chen¹, Kevin J Glaser¹, Meng Yin¹, Phillip J Rossman¹, and Richard L Ehman^1
1Radiology Department, Mayo Clinic, Rochester, MN, United States, ²Radiology Department, Beijing Anzhen Hospital, Capital Medical University, Beijing, Beijing, China

To investigate the feasibility of using MRE for the evaluation of the mechanical properties of the in vivo aortic wall. The feasibility of performing pulse-gated cine MRE technique in the abdominal aorta was assessed in five healthy volunteers. In the study, the waves were well visualized within the lumen of the abdominal aorta in the diastolic phase, but they were not well visualized during systole. A significant correlation between E*t product of aortic wall in the five volunteers and their age was revealed (r2=0.81). The study shows that MRE is feasible for assessing the elastic properties of the abdominal aorta.

Jesse Habets¹, Herman J.A. Zandvoort², Johannes B. Reitsma³, Frans L. Moll², L. Wilbert Bartels⁴, Joost A. van Herwaarden², and Tim Leiner^1
1Radiology, University Medical Center Utrecht, Utrecht, Netherlands, ²Vascular Surgery, University Medical Center Utrecht, Utrecht, Netherlands, ³Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, Netherlands, ⁴Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands

This systematic review and meta-analysis demonstrates that magnetic resonance imaging (MRI) is a more sensitive imaging modality than computed tomography angiography (CTA) for the detection of endoleaks in patients after endovascular abdominal aortic aneurysm repair (EVAR). Blood pooling contrast agents may have additional diagnostic value compared to extracellular gadolinium chelates.

Elke Angelika Lassel¹, Gina-Lisa Friese¹, Lothar R Pilz², Stefan O Schoenberg¹, and Henrik J Michaely^1
1Department of Clinical Radiology and Nuclear Medicine, University Medical Centre Mannheim, Mannheim, Baden-Württemberg, Germany, ²Statistics, Medical Faculty Mannheim at Heidelberg University, Germany

The aim of this study was to identify MRA-based factors that influence the patient’s outcome, especially the overall survival, the time to infarct and limb amputation. Based on 124 patients with MRA of the lower extremities with at least 1 year follow-up time the impact of different MR-based and clinical parameters on survival and time to the first cardiovascular event were assessed by a Cox proportional hazard model. The only factor with significant impact on overall survival was the number of patent calf vessels (HR=0.688; p=0.0048) while the time to the first cardiovascular event was dependent on various factors.

Conor P Meehan¹, Sarah N Khan¹, Maria Ines Boechat¹, and J Paul Finn^1
1Diagnostic Cardiovascular Imaging, David Geffen School of Medicine, UCLA, Los Angeles, CA, United States

High- resolution contrast enhanced MRA (CEMRA) at 3.0T provides consistent, high quality evaluation of vascular anatomy in pediatric transplant patients and can provide comprehensive vascular information prior to and following liver, small bowel and pancreas transplantation. We report the initial findings in 29 consecutive pediatric patients.

Ronald van 't Klooster¹, Marius Staring¹, Stefan Klein², Robert Kwee³, Eline Kooi³, Johan Reiber¹, Boudewijn Lelieveldt¹, and Rob van der Geest^1
1Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands, ²Biomedical Imaging Group Rotterdam, Depts. Of Radiology & Medical Informatics, Erasmus MC, Rotterdam, Netherlands, ³Department of Radiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, Netherlands

Patient movement during scanning can cause misalignments between multispectral MR images. Correctly aligned images of the carotid artery are needed to accurately classify plaque components inside the vessel wall. Manual alignment of these images is the current procedure but is time-consuming. Automatic image registration can be applied to correct for these misalignments. Various registration techniques were investigated and quantitatively validated with a gold standard. The results show that automatic image registration using a 3D B-spline transform can replace the manual alignment procedure reducing the amount of time needed analyzing carotid vessel wall images.

Qingjun Wang¹, Yong Guo², Jianming Cai³, and Minghua Huang^4
1Department of Radiology, Chinese Navy General Hospital, Beijing, Beijing, China, ²Department of Radiology, Chinese Navy General Hospital, China, ³Chinese PLA General Hospital, ⁴Chinese Navy General Hospital

After comparing with digital subtraction angiography (DSA) and high-resolution two-dimensional oblique-sagittal black-blood magnetic resonance imaging (2D-BB-MRI), we evaluated the value of high-resolution three-dimensional oblique-sagittal black-blood magnetic resonance imaging (3D-BB-MRI) in carotid artery stenting (CAS) for atherosclerotic carotid stenosis with cerebrovascular ischemic events. Two radiologists evaluated the maximum stenosis (Max-stenosis), maximum transverse plaque thickness (Max-TPT) and location of maximal lumen stenosis, plaque rupture, degree of maximal lumen stenosis and maximum longitudinal plaque extension (Max-LPE) on MRI images by consensus, and then compared the results with DSA. Our findings showed that the 3D-BB-MRI can provide a good preoperative preparation for CAS.

Julien Sein¹, Shahram Majidi², Saqib Chaudry², Nauman Tariq², Dingxin Wang^1,3, Gregor Adriany¹, Eddie Auerbach¹, Kamil Ugurbil¹, Muhammad Fareed Suri², and Pierre-Francois Van de Moortele^1
1CMRR, University of Minnesota, Minneapolis, Minnesota, United States, ²Zeenat Qureshi Stroke Research Center, University of Minnesota, Minneapolis, Minnesota, United States, ³Siemens Medical Solutions USA, Inc.

Brain vessel wall MRI is expected to benefit from gains in SNR and tissue contrast at high magnetic fields. A 7-Tesla human MRI scanner was chosen to investigate both ex-vivo and in-vivo achievable cerebral vessel MR. Ex-vivo samples excised from human cadaver brains in the Circle of Willis area were imaged with the 3D SPACE MR sequence. In vivo, a pool of healthy subjects was scanned at 0.64 mm isotropic resolution with same sequence. Comparison of ex-vivo MR images with virtual histology intravascular ultrasound allowed for distinction of vessel wall boundaries and plaque components on MR images.

Vitaliy L. Rayz¹, Monica Sigovan¹, and David Saloner^1
1Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, United States

4D MRI data, providing time-resolved velocity measurements in vivo, can be used to prescribe patient-specific boundary conditions for detailed numerical simulations. This approach connects a computational domain to the proximal and distal circulation, eliminating uncertainties of various modeling assumptions commonly used in the flow modeling practice. We have used 4D MRI to prescribe flow boundaries for computations in a cerebral aneurysm and an arteriovenous fistula and compared these results to computations carried out based on specific different assumptions about the distal circulation. The study demonstrates that boundary conditions based on 4D MRI measurements ensure the accuracy of the numerical simulations.

Delphine Perie¹, Anthony Foudis¹, Gilles Beaudoin², Guillaume Gilbert³, Nagib Dahdah⁴, and Daniel Curnier^5
1Mechanical Engineering, Ecole Polytechnique de Montreal, Montreal, Quebec, Canada, ²Physics and Biomedical Engineering, CHUM Hopital Saint-Luc, Montreal, quebec, Canada, ³MR Clinical Science, Philips Healthcare, Cleveland, OH, United States, ⁴Cardiology, CHU Sainte-Justine, Montreal, Quebec, Canada, ⁵Kinesiology, Universite de Montreal, Montreal, Quebec, Canada

The long-term objective is to develop a sensitive and non-invasive technique allowing the early detection and the follow-up of the changes occurring within the mechanical properties of cardiac tissues with cardiomyopathy. We hypothesized that a relationship exists between mechanical properties and MR parameters of cardiac tissues. Porcine hearts were submitted to a quantitative MRI acquisition followed by a tensile test until rupture. The significant relationship found between the Young’s modulus and the MRI parameters T1, FA and ADC is the basis for the development of an indirect tool for the in vivo evaluation of the mechanical properties of cardiac tissues. Kriging is a powerful tool that optimizes theses relationships.

Maureen N Hood^1,2, Ting Song^1,3, Peter Bedocs⁴, John F Capacchione⁴, Christine E Kasper^2,5, Mark C Haigney⁶, and Vincent B Ho^1
1Radiology & Radiological Sciences, Uniformed Services University, Bethesda, Maryland, United States, ²Graduate School of Nursing, Uniformed Services University, Bethesda, Maryland, United States, ³Global Applied Science Laboratory, GE Healthcare, Bethesda, Maryland, United States, ⁴Anesthesiology, Uniformed Services University, Bethesda, Maryland, United States, ⁵Nursing, department of Veteran Affairs, Washington, District of Columbia, United States, ⁶Cardiology, Uniformed Services University, Bethesda, Maryland, United States

T1 mapping may be a promising technique to quantify myocardial changes in heart failure even when the subject cannot hold their breath. T1 mapping using modified look-locker with saturation recovery in this small swine study shows a quantitative difference in T1 value between healthy baseline and heart failure hearts. The immunochemistry suggests a change in amounts of Type I, III and VI collagen in the myocardium between the control and heart failure swine, but more research needs to be done.