Marianna Inglese¹, Shah Islam¹, Matthew Grech-Sollars^1,2, Giulio Anichini³, James Davies⁴, Azeem Saleem^4,5, Matthew Williams^6,7, Kevin S O'Neill³, Adam D Waldman⁸, and Eric O Aboagye^1
1Surgery and Cancer, Imperial College London, London, United Kingdom, ²Imaging, Imperial College London Healthcare NHS Trust, London, United Kingdom, ³Imperial College London Healthcare NHS Trust, London, United Kingdom, ⁴Invicro Imperial College London, London, United Kingdom, ⁵Hull York Medical School, Faculty of Health Sciences, University of Hull, Hull, United Kingdom, ⁶Computational Oncology Group, Department of Surgery and Cancer, Imperial College London, London, United Kingdom, ⁷Institute for Global Health Innovation, Imperial College London, London, United Kingdom, ⁸Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom

¹⁸F-FPIA PET/MRI integrates two imaging modalities that can provide valuable insight into the characterization and classification of brain tumours.

10 patients with primary brain gliomas were recruited to this study. Static and dynamic ¹⁸F-FPIA PET, together with perfusion/diffusion MRI data were post-processed for the extraction of 3D parametric maps for each subject. Correlations among parameters were evaluated with Spearman test. Tumour grade prediction was assessed with a machine learning model.

A strong correlation was found between uptake and influx rate constant of FPIA and MRI perfusion parameters. The PET/MRI methodology provided 100% accuracy in differentiating low from high grade tumours.

Huilou Liang^1,2, Lianwang Li³, Yuchao Liang³, Siqi Cai⁴, Jing An⁵, Yan Zhuo^1,2,6, Lijuan Zhang⁴, Danny JJ Wang⁷, and Rong Xue^1,2,8
1State Key Laboratory of Brain and Cognitive Science, Beijing MRI Center for Brain Research, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, ²University of Chinese Academy of Sciences, Beijing, China, ³Department of Neurosurgery, Beijing Tiantan Hospital of Capital Medical University, Beijing, China, ⁴Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China, ⁵Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen, China, ⁶CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Beijing, China, ⁷Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States, ⁸Beijing Institute for Brain Disorders, Beijing, China

Arterial spin labeling (ASL) perfusion MRI with single post-labeling delay (PLD) has been used to noninvasively predict the IDH1 mutation status in glioblastoma patients. However, single-delay ASL can make inaccurate estimations of cerebral blood flows (CBF) due to the variability of arterial transit times (ATT) among individuals. In this study, we applied multi-delay 3D ASL technique with multiple hemodynamic parameters including quantitative ATT, ATT-corrected CBF and arterial cerebral blood volume (aCBV) in glioblastoma. Our results show that aCBV-based relative perfusion parameters may provide a better identification of IDH1 mutation status and is worthy of further verification in future studies.

Limin Zhou¹, Yiming Wang¹, Marco Da Cunha Pinho^1,2, Edward Pan^3,4,5, Yin Xi^1,6, Joseph A Maldjian^1,2, and Ananth J Madhuranthakam^1,2
1Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, ²Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States, ³Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, DALLAS, TX, United States, ⁴Department of Neurological Surgery, University of Texas Southwestern Medical Center, DALLAS, TX, United States, ⁵Harold C. Simmons Cancer Center, University of Texas Southwestern Medical Center, DALLAS, TX, United States, ⁶Department of Population and Data Sciences, University of Texas Southwestern Medical Center, Dallas, TX, United States

A 3D TSE using Cartesian acquisition with spiral profile reordering (CASPR) in combination with pseudo-continuous arterial spin labeling (pCASL) was developed to improve the robustness of ASL measured perfusion to increased B0 inhomogeneities in GBM patients. Previous results showed high intrasession reliability of this method in GBM patients. In this study, we compared the 3D TSE-CASPR measured perfusion with clinically available 3D GraSE at 3T. With 24 GBM imaging sessions, the results showed that 3D pCASL with TSE-CASPR is more robust to B0 inhomogeneities and has higher intrasession reliability than the clinical sequence, 3D pCASL with GraSE at 3T.

Lu Chen¹, Guo-Yi Su¹, Weiqiang Dou², Yong Shen³, Fei-Yun Wu¹, and Xiao-Quan Xu^1
1Radiology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China, ²GE Healthcare, MR Research China, Beijing, P.R. China, Beijing, China, ³GE Healthcare, MR Enhanced Application China, Beijing, P.R. China, Beijing, China

In this study, we aimed to investigate 3D pcASL with multiple PLDs in evaluating subtypes of parotid gland tumors. By quantitatively measuring tumor blood flow (TBF) and comparing the values within and between subgroups, we found 3D pcASL with multiple PLDs can differentiate parotid gland tumors and reflect changes of TBF. With these findings, 3D pcASL MRI, especially with short PLD was suggested to evaluate patients with parotid gland tumors in routine clinical practice.

Jörn Huber¹, Daniel Hoinkiss¹, and Matthias Günther^1,2
1Fraunhofer MEVIS, Bremen, Germany, ²University of Bremen, Bremen, Germany

Liver perfusion can give valuable functional information about diseases like carcinoma and cirrhosis. Arterial Spin Labeling allows non-invasive assessment of liver perfusion without exogenous contrast agents being especially helpful in patients with renal failure. ASL in abdominal organs like liver faces increased challenges due to low perfusion rates, breathing motion and strong off-resonance as well as B1-inhomogeneity. In this work, a robust implementation of a pulsed ASL (PASL) sequence with FAIR labeling and 3D GRASE readout is provided, addressing these difficulties. 

Peiyao Chen¹, Chao Jin¹, Xianjun Li¹, Miaomiao Wang¹, Congcong Liu¹, Xiaoyu Wang¹, Fan Wu¹, Yuli Zhang¹, Cong Tian¹, Mengxuan Li¹, Xiaocheng Wei², and Jian Yang^1
1First Affiliated Hospital of Xi 'an Jiaotong University, Xi'an, Shaanxi, China, ²MR Research China, GE Healthcare, Beijing, China

Adequate cerebral blood flow (CBF) is essential for development of brain structure and function. However, little is known about the developmental trajectory of CBF across the broad age range in childhood. This study aims to investigate the spatiotemporal evolution of CBF in cerebral cortex and basal ganglia in healthy term children aged from 28 days to 15 years. Our results indicated that the estimated age with highest CBF was earliest in the occipital lobe, followed by temporal and parietal lobe, at last in the frontal lobe. The perfusion of basal ganglia showed a U-shaped curve, which slowly increased with age.

Hongri Chen¹, Weiqiang Dou², and Wei yin Liu^2
1Dalian Medical University, Northern Jiangsu People’s Hospital, Yangzhou, China, Yangzhou, China, ²GE Healthcare, MR Research China, Beijing, P.R. China, Beijing, China

  The present study was to explore regional perfusion changes in patients with Parkinson's disease dementia (PDD) and Alzheimer’s disease (AD) using 3D arterial spin labeling MRI and further assess the corresponding difference between PDD and AD patients. The results revealed that the perfusion pattern in PDD group was distinct from that in AD group despite of overlapped perfusion regions. The resultant normalized cerebral blood flow (CBF) can distinguish PDD from AD. Therefore, normalized CBF provided sensitive imaging-based markers that contribute to the diagnosis and differential diagnosis of the two dementia.

Daniele Mascali¹, Antonio Maria Chiarelli¹, Ilona Lipp^2,3, Anna Digiovanni⁴, Valentina Tomassini^1,3,4, and Richard Geoffrey Wise^1,3
1Institute for Advanced Biomedical Technologies,Department of Neuroscience, Imaging and Clinical Sciences, "G. D'Annunzio University" of Chieti-Pescara, Chieti, Italy, ²Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ³Cardiff University Brain Research Imaging Centre (CUBRIC) School of Psychology, Cardiff University, Cardiff, United Kingdom, ⁴MS Centre, Neurology Unit, SS. Annunziata University Hospital, Chieti, Italy

We investigated the relationship between grey matter perfusion and clinical and conventional MRI measures in patients with relapsing multiple sclerosis (MS) to test the hypothesis that an impaired energy supply is associated with the development of brain damage and clinical disability. Using multi-inversion time pulsed ASL we demonstrated that MS patients have significantly lower cerebral grey matter perfusion when compared to healthy controls. In the patients, lower perfusion correlates with greater tendency to develop irreversible tissue damage and with worse clinical scores, suggesting that altered energy supply may directly contribute to damage and disability in MS.

Clara Delacour¹, Ahmed-Ali El Ahmadi¹, Gilles Brun¹, Nadine Girard^1,2, Christoph Heesen^3,4, Arzu Ceylan Has^3,4, and Jan-Patrick Stellmann^2,3,4,5
1Neuroradiology, APHM La Timone, Marseille, France, ²Aix-Marseille Univ, CNRS, CRMBM, UMR 7339, Marseille, France, ³Institute of Neuroimmunology and MS (INIMS), University Medical Centre Hamburg-Eppendorf, Hamburg-Eppendorf, Germany, ⁴Neurology, University medical centre Hamburg-Eppendorf, Hamburg-Eppendorf, Germany, ⁵APHM La Timone, CEMEREM, Marseille, France

Disability progression in Multiple Sclerosis (MS) is driven by inflammation and neurodegeneration. Arterial spin labelling (ASL) is a non-invasive MRI method for the assessment of brain perfusion without the need for gadolinium. Here, we explored ASL perfusion as a biomarker for diseases progression and disability in a cohort of 77 patients with primary progressive MS (PPMS). While brain perfusion seemed rather stable during the follow-up of up to 5 years, we observed an association between higher regional perfusion rates and cognitive performance and hand functioning. Altered perfusion in PPMS seems thus not closely related to the major pathomechanism neurodegeneration.

Sudipto Dolui¹, Audrey P. Fan^2,3, Moss Y. Zhao³, Greg Zaharchuk³, and John A. Detre^1,4
1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States, ²Departments of Biomedical Engineering and Neurology, University of California, Davis, CA, United States, ³Department of Radiology, Stanford University, Palo Alto, CA, United States, ⁴Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States

Periventricular white matter (PVWM) is exclusively perfused by small vessels, and hence PVWM Cerebral Blood Flow (CBF) can provide a biomarker of cerebral small vessel functional integrity. Although PVWM is weakly perfused, we demonstrate that PVWM-CBF derived from state-of-the-art Arterial Spin Labeling (ASL) acquired twice ~15minutes apart in a cohort of 16 subjects showed high reproducibility that was comparable to other larger regions of interest. Further there was high correlation between PVWM-CBF derived from ASL and concurrently acquired [¹⁵O]-water Positron Emission Tomography data. These findings suggest that PVWM CBF can be reliably measured with advanced ASL methods.

Bhaswati Roy¹, Susana Vacas¹, Kathy McCloy², Rajan Saggar², and Rajesh Kumar^1,3,4,5
1Anesthesiology, University of California Los Angeles, Los Angeles, CA, United States, ²Medicine, University of California Los Angeles, Los Angeles, CA, United States, ³Bioengineering, University of California Los Angeles, Los Angeles, CA, United States, ⁴Radiological Sciences, University of California Los Angeles, Los Angeles, CA, United States, ⁵Brain Research Institute, University of California Los Angeles, Los Angeles, CA, United States

Pulmonary arterial hypertension (PAH) patients show cognitive and mood impairments, and brain tissue injury in those areas. However, the underlying cause of tissue damage in PAH patients remain unclear. Altered cerebral blood flow (CBF) may contribute to develop brain tissue injury and cognitive and mood deficits. We evaluated CBF in PAH patients over controls, and found changes in the prefrontal cortices, insula, cingulate, frontal cortex, corona radiate, temporal, occipital, and parietal gyrus. Significant correlations also emerged between CBF and functional deficits in PAH, including mood and cognition symptoms, implying altered hemodynamic contributing to brain changes and functional deficits.  

Colette C. Milbourn¹, Thomas W. Okell², and Nicholas P. Blockley^1
1The School of Life Sciences, University of Nottingham, Nottingham, United Kingdom, ²Wellcome Centre for Integrative Neuroimaging, FMRIB, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom

New clinical tools are needed for the diagnosis and prognosis of cerebrovascular diseases. Pseudocontinuous Arterial Spin Labelling (pCASL) is recommended for quantifying tissue cerebral blood flow due to its superior signal-to-noise. Stressors to the brain like high carbon dioxide (hypercapnia), used to map Cerebrovascular Reactivity (CVR), are known to reduce the labelling efficiency of pCASL and therefore underestimate CVR. In this study a systematic difference in CVR was observed across measurements made with three different sets of pCASL parameters. Ultimately this work will help to determine pCASL parameters that minimise systematic error and produce robust quantitative estimates of CVR.

Moss Y Zhao¹, Audrey P Fan², David Chen^3,4, Jia Guo⁵, Yosuke Ishii⁶, David Shin⁷, Mohammad Mehdi Khalighi¹, Dawn Holley¹, Kim Halbert¹, Andrea Otte¹, Brittney Williams¹, Jun-Hyung Park¹, Bin Shen¹, Gary Steinberg⁸, and Greg Zaharchuk^1
1Radiology, Stanford University, Stanford, CA, United States, ²Biomedical Engineering and Neurology, University of California Davis, Davis, CA, United States, ³Medical Imaging, Taipei Medical University – Shuan-Ho Hospital, New Taipei City, Taiwan, ⁴Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, ⁵Bioengineering, University of California Riverside, Riverside, CA, United States, ⁶Neurosurgery, Tokyo Medical and Dental University, Tokyo, Japan, ⁷GE Healthcare, Melo Park, CA, United States, ⁸Neurosurgery, Stanford University, Stanford, CA, United States

Cerebrovascular reactivity (CVR) reflects the capacity of the brain to respond to external stress. Impaired CVR leads to a higher risk of stroke. The standard CVR measuring tool relied on PET imaging but is inaccessible to most patients. Here we investigate the CVR of Moyamoya patients using arterial spin labeling (ASL), a non-invasive and quantitative MRI technique. Results showed that significant lower CVR was found in flow territories with severe stenosis or occlusion, making ASL a potential diagnostic tool to predict the risk of stroke for patients with vasculopathy.

Chenyang Zhao¹, Ze Wang², and Danny Wang^1
1Laboratory of Functional MRI Technology (LOFT), Mark & Mary Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, United States, ²Department of Diagnostic Radiology and Nuclear Medicine, School of Medicine, University of Maryland, Baltimore, MD, United States

A digital brain perfusion phantom was designed using a representative 5-delay 3D pCASL protocol and applied to validate the quantification accuracy of 4 ASL post-processing software packages, including ASLtbx, ASL_MRICloud, BASIL, and Cereflow. The 4 tested software can produce generally correct quantification results under normal SNR conditions, however their accuracy may be affected by the limitation occurred in low perfusion regions and low SNR condition. The digital phantom provides a reliable reference with high flexibility to validate ASL post-processing software.

Shichun Chen¹, Yakun Zhang¹, Zongpai Zhang¹, Wenna Duan¹, George Weinschenk¹, Brandon E. Gibb², Wenming Luh³, and Weiying Dai^1
1Department of Computer Science, State University of New York at Binghamton, Binghamton, NY, United States, ²Department of Psychology, State University of New York at Binghamton, Binghamton, NY, United States, ³National Institute on Aging, National Institutes of Health, Baltimore, MD, United States

We investigated the relationship between brain global activity or global topology of brain networks and attentional processes. The former measures were evaluated by dynamic arterial spin labeling (ASL) perfusion fMRI. The latter measures were assessed by P3 amplitude and latency in event-related potentials (ERPs). The P3 properties were significantly correlated with numbers of correct response. We found positive associations between global perfusion and P3 amplitude and between characteristic path length and P3 latency, and negative associations between global perfusion, global efficiency, mean functional connectivity and P3 latency, indicating close correlation of brain global behavior and attention.

Qihao Zhang¹, Jana Ivanidze², Thanh Nguyen², Pascal Spincemaille², and Yi Wang^1
1Cornell University, New York, NY, United States, ²Weill Cornell Medical College, New York, NY, United States

We propose to exam the water exchange rate (k_w) change after caffeine uptake based on an optimized diffusion prepared arterial spin labeling (ASL) sequence and reconstruction method in a previous work1. 5 subjects went through two scans to test the reproducibility of the  reconstruction pipeline. Another 5 subjects are scanned before and half an hour after caffeine uptake. Cerebral blood flow (CBF) and  are reconstructed from the ASL images. A 26% decrease in CBF and 13% decrease of k_w is observed.

Manuel Taso¹, Uri Wollner², Arnaud Guidon³, Rafi Barda², Christopher J Hardy⁴, Sangtae Ahn⁴, and David C Alsop^1
1Division of MRI research, Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, United States, ²GE Research, Herzliya, Israel, ³Global MR Applications and Workflow, GE Healthcare, Boston, MA, United States, ⁴GE Research, Niskayuna, NY, United States

Arterial spin labeling (ASL) has proven to be a powerful research and clinical technique for functional imaging of tissues. The combination of undersampled acquisitions and compressed sensing reconstruction shows promise for increased speed, resolution, and robustness but conventional CS reconstructions are slow and may not be satisfactory, especially for low SNR data. This work explores the feasibility and performance of Deep-Learning based reconstruction of similarly sampled data to realize the full potential of these ASL acquisitions using DCI-net, an unenrolled iterative CS network. We show DCI-net performance at high acceleration rates and potential for fast volumetric ASL perfusion imaging. 

Rebeca Echeverria-Chasco^1,2, Marta Vidorreta³, Veronica Aramendia-Vidaurreta^2,4, David Cano ¹, Gorka Bastarrika^2,4, Nuria Garcia-Fernandez^2,5, Paloma L. Martin Moreno^2,5, and Maria A. Fernandez-Seara^2,4
1Radiology, Clínica Universidad de Navarra, Pamplona, NE, Spain, ²IdiSNA, Instituto de Investigación Sanitaria de Navarra, Pamplona, Spain, ³Siemens Healthineers, Madrid, Spain, ⁴Radiology, Clínica Universidad de Navarra, Pamplona, Spain, ⁵Nephrology, Clínica Universidad de Navarra, Pamplona, Spain

The goals of this work were to test a multiparametric MRI protocol to measure perfusion, diffusion and T1 and to assess inter-session reproducibility in a group of transplanted patients with stable renal function.

18 patients were imaged in 2 exams employing pseudo-continuous arterial spin labeling technique, intravoxel incoherent motion technique and T1 mapping sequence. Reproducibility was assessed using Bland-Altman analysis, within-subject coefficient of variation (CVws) and intra-class correlation coefficient (ICC).

Results of the 3 techniques were promising showing a CVws <20% in most of the cases (especially for T1 and D (<6%)) and high ICC coefficients for PCASL and T1.

Petros Martirosian¹, Rolf Pohmann², Martin Schwartz^1,3, Thomas Kuestner⁴, Manuel Kolb⁴, Ahmed Othman⁴, Cecilia Zhang⁴, Klaus Scheffler^2,5, Konstantin Nikolaou⁴, Fritz Schick¹, and Ferdinand Seith^4
1Section on Experimental Radiology, University of Tübingen, Tübingen, Germany, ²Max Planck Institute for Biological Cybernetics, Tübingen, Germany, ³Institute of Signal Processing and System Theory, University of Stuttgart, Stuttgart, Germany, ⁴Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen, Germany, ⁵Department of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany

Pseudo-continuous-arterial-spin-labeling (PCASL) has been successfully applied in the lung providing high quality perfusion images. The pulmonary blood flow and the respiratory system interact closely: the intrathoracic pressure has impact on the venous return. Therefore, in this work, we evaluate the effects of intrathoracic pressure on lung perfusion by using PCASL imaging in end-expiratory and end-inspiratory breath-hold. PCASL imaging is able to detect changes of parenchymal lung perfusion caused by alterations of the intrathoracic pressure. Perfusion signal measured under end-inspiratory condition were noticeably reduced as compared to end-expiratory breath-hold. This correlated significantly with measured blood flow volume through the pulmonary trunk.

Dapeng Liu^1,2, Dan Zhu³, Wenbo Li^1,2, and Qin Qin^1,2
1Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, ²F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, ³Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States

Prostate perfusion mapping using velocity-selective arterial spin labeling (VSASL) is desired for higher SNR and insensitivity to arterial transit delay. The choice of cutoff velocity (Vc) determines its sensitivity to perfusion-weighted signal (PWS). The utility of Fourier-transform based velocity-selective (FT-VS) pulse trains have been demonstrated in cerebral blood flow and cerebral blood volume mapping. In this study, FT-VS prepared blood flow and blood volume mapping sequences were performed in parallel in both brain and prostate to investigate their Vc dependence to PWS. The results suggest that lower Vc is demanded for prostate VSASL.