MRI in Stroke: Vessels, Flow & Tissue Structure
Neuro Thursday, 20 May 2021

Oral Session - MRI in Stroke: Vessels, Flow & Tissue Structure
Neuro
Thursday, 20 May 2021 16:00 - 18:00
  • Evaluation of primary and secondary collateral pathways in carotid artery stenosis patients before and after revascularization therapy
    Lena Schmitzer1, Alexander Seiler2, Nico Sollmann1, Christine Preibisch1,3, Kilian Weiss4, Claus Zimmer1, Fahmeed Hyder5, Jens Göttler1,5, and Stephan Kaczmarz1,5
    1School of Medicine, Department of Neuroradiology, Technical University of Munich, Munich, Germany, 2Department of Neurology, Goethe University Frankfurt, Frankfurt, Germany, 3School of Medicine, Clinic of Neurology, Technical University of Munich, Munich, Germany, 4Philips Healthcare, Hamburg, Germany, 5MRRC, Yale University, New Haven, CT, United States
    Therapy outcome in patients with internal carotid artery stenosis (ICAS) might be determined by collateral flow. We thus investigated primary and secondary collaterals in ICAS patients and found protective effects of an intact Circle of Willis.

    Figure 3. Box plots of DC indicate stronger spatial shifts of iWSAs in patients with poor Circle of Willis configuration.

    The boxes contain all single-subject DC values between the first and third quartiles, the line inside marks the median, and the whiskers reach from minimum to maximum (not including outliers). In patients with poor Circle of Willis configuration (left), iWSA overlap between scan 1 and 2 differed more between hemispheres (p=0.007) while patients with sound configuration of the CoW did not present significant side differences (p=0.938).

    Figure 4. Paired Scatter Plots comparing single-subject coefficients of variance within the high CoV mask.

    Data points represent mean coefficients of variance (CoV) of each subject for each hemisphere, lines connect the mean CoV between hemispheres. The red dashed line displays the group average. Stable CoV was found between hemispheres for both groups and scans. A two-sided t-test revealed no significant differences between hemispheres (controls in scan 1/2: p=0.86/0.94; patients in scan 1/2: p=0.92/0.92).

  • Inner volume 3D TSE using optimized spatially selective excitation pulses for vessel wall imaging of intracranial perforating arteries at 7T
    Qingle Kong1,2, Yue Wu1, Dehe Weng3, Jing An3, Yan Zhuo1,4, and Zihao Zhang1,4
    1Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 2MR Collaboration, Siemens Healthcare Ltd, Beijing, China, 3Siemens Shenzhen Magnetic Resonance Ltd, Shenzhen, China, 4The Innovation Center of Excellence on Brain Science, Chinese Academy of Sciences, Beijing, China
    The inner-volume 3D TSE sequence with optimized spatially selective excitation RF pulses was developed to achieve isotropic 0.30 mm black-blood images within ten minutes for the first time. The IV-SPACE images showed clearer delineation of vessel wall of LSA than conventional SPACE images.
    Figure 4. Coronal MinIP images of 2D RF (a), optimized method (b), and conventional SPACE (c). The optimization method achieves more thorough signal suppression compare to traditional 2D RF and suffer from fewer aliasing artifacts (white arrow). Due to the increase in spatial resolution, the optimized method shows more branches that are invisible to conventional SPACE images (yellow arrows).
    Figure 5. The comparisons of IV-SPACE and conventional SPACE in the coronal plane. The enlarged images were shown on the right side. The lumen and orifice of an LSA are clearly depicted in the IV-SPACE image, whereas the lumen and orifice of the vessel were blurred in conventional SPACE. The depiction of the LSA vessel wall of IV-SPACE is also better than conventional SPACE.
  • Evaluation of leptomeningeal collaterals by DSC-based signal variance and hemodynamic features in asymptomatic carotid artery stenosis
    Stephan Kaczmarz1,2, Lena Schmitzer1, Jens Göttler1,2, Kilian Weiss3, Christian Sorg1, Claus Zimmer1, Fahmeed Hyder2, Christine Preibisch1, and Alexander Seiler4
    1School of Medicine, Department of Neuroradiology, Technical University of Munich (TUM), Munich, Germany, 2MRRC, Yale University, New Haven, CT, United States, 3Philips Healthcare, Hamburg, Germany, 4Department of Neurology, Goethe University Frankfurt, Frankfurt, Germany
    Signal variance characteristics of perfusion-weighted MRI did not indicate leptomeningeal collateralization in asymptomatic carotid artery stenosis, but may detect vascular voxels at risk for future collateral recruitment according to multi-parametric hemodynamic characterization
    Figure 1: MRI Protocol and derived parameters. Grey matter (GM) masks were derived from structural imaging, cerebral blood flow (CBF) by pseudo-continuous arterial spin labeling (pCASL),17 relative cerebral blood volume (rCBV) by dynamic susceptibility contrast (DSC)16 and combined with T2* and T2 yielding relative oxygen extraction fraction (rOEF)17. Based on the DSC time-series, voxels with high coefficient of variation (CoV, see Eq.1) were segmented (orange)12 and applied to hemodynamic parameters (green) after exclusion of ventricles and large vessels15 (red).

    Figure 4: Hemodynamic characteristics in high-CoV voxels. CBF (A), rCBV (B) and rOEF (C) are compared in grey matter (GM; yellow) vs. high-CoV voxels (CoV; red) in healthy controls (HC; green) and ICAS patients (orange). Dots show mean parameter values, black lines connect the same subject’s mean values and red dashed lines represent group average values. CBF was systematically lower due to background suppression13 and rOEF elevated due to T2 bias26. In high-CoV voxels of both groups, all parameters showed significant effects. While CBF (A) and rCBV (B) were higher, rOEF was lower (C).

  • GraspMRA: High Temporal Resolution, Non-Contrast Enhanced, Time-Resolved 4D MR Angiography Using Golden-angle Radial Sparse Parallel Imaging
    Li Feng1 and Lirong Yan2
    1Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, 2USC Stevens Neuroimaging and Informatics Institute, University of Southern California, Los Angeles, CA, United States
    Highly-accelerated 4D MRA using golden-angle radial sparse parallel imaging with subspace-based image reconstruction (GraspMRA) was proposed and evaluated, which can achieve temporal resolution of up to 50 ms with 10 spokes per frame.
    Figure 1. The flowchart of GRASP-Pro reconstruction. In an intermediate step, standard GRASP reconstruction is performed on the low-resolution portion of the sorted radial k-space for estimating temporal basis (U). In the second step, GRASP-Pro is then performed on the full-resolution radial k-space incorporating the pre-learned basis (UK with only the first dominant K basis components) to reconstruct VK, the coefficients to represent the fully-resolution image-series under UK. The final images m is then computed as UKVK.
    Figure 3. MRA MIP images at 5 representative phases with 10 and 20 spokes per frame, respectively. MIP images at the same TIs were shown for the two reconstructions for better comparison.
  • Cerebrovascular relative pressure assessment using 4D Flow MRI – accuracy of image-based estimation approaches
    David Marlevi1, Jonas Schollenberger2, Maria Aristova3, Edward Ferdian4, Alistair A Young4,5, Elazer R Edelman1, Susanne Schnell3,6, C. Alberto Figueroa2, and David Nordsletten2,5
    1Massachusetts Institute of Technology, Cambridge, MA, United States, 2University of Michigan, Ann Arbor, MI, United States, 3Northwestern University, Chicago, IL, United States, 4University of Auckland, Auckland, New Zealand, 5King's College London, London, United Kingdom, 6University of Greifswald, Greifswald, Germany
    Using in-silico and in-vivo experiments, we show how accurate estimates of cerebrovascular relative pressure can be achieved by 4D Flow MRI. However, accuracy depends on resolution (dx < 0.75 mm3) and estimation approach (optimized by a virtual work-energy relative pressure (vWERP) method). 
    Figure 1: (left) In-silico model of the arterial cerebrovascular space, showing the extracted velocity and pressure field of the main vessels of the circle of Willis; (right) Example output from the separate in-vivo 4D Flow MRI analysis, showing time-integrated pathlines within vessel regions superimposed on axial magnitude images for two individuals, each at dx = 1.1 and 0.3 mm3.
    Figure 2: Linear regression plots for different spatial resolutions, comparing estimated relative pressure output ( by RB, UB, and vWERP) against reference CFD relative pressure ($$$\Delta p$$$). Colors indicate estimates over individual vascular sections shown in the diagram to the left.
  • Vessel distance mapping for deep gray matter structures
    Hendrik Mattern1, Stefanie Schreiber2,3,4, and Oliver Speck1,3,4,5
    1Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany, 2Department of Neurology, Otto-von-Guericke-University, Magdeburg, Magdeburg, Germany, 3German Center for Neurodegenerative Disease, Magdeburg, Germany, 4Center for Behavioral Brain Sciences, Magdeburg, Germany, 5Leibniz Institute for Neurobiology, Magdeburg, Germany
    Vessel distance mapping (VDM) is proposed as a novel tool to enable quantitative and qualitative assessment of vascular patterns in deep gray matter structures. 

    Figure 1: Data processing workflow: Image data and ROI masks are taken as inputs. Vessels are first enhanced and then segmented. After generating the skeleton, a vessel distance map can be computed by applying the Euclidian distance transform. Local vessel density and VDM estimates are computed from the segmentation and distance maps respectively.

    MIP – Maximum Intensity Projection; ROI – Region of Interest; VDM – Vessel Distance Mapping

    Figure 5: Arterial and venous distance maps of the left hippocampus (central slice shown). By co-registering all subjects to the study template space a group VDM average could be computed. For comparison, all segmentations have been averaged in the template space (shown as MIP) to show the overlap of the vascular patterns.

    MIP – Maximum Intensity Projection; VDM – Vessel Distance Mapping

  • Recanalization of Acute Intracranial Large Vessel Occlusions: Novel Findings from High-Resolution Vessel Wall Imaging
    Chen Cao1,2, Jing Lei2, Yan Gong3, Song Jin2, Jinxia Zhu4, Ming Wei5, and Shuang Xia6
    1Department of Radiology, First Central Clinical College, Tianjin Medical University, Tianjin, China, 2Department of Radiology, Tianjin Huanhu Hospital, Tianjin, China, 3Department of Radiology, Tianjin Medical University Nankai Hospital, Tianjin, China, 4MR Collaboration, Siemens Healthcare Ltd., Beijing, China, 5Department of Neurosurgery, Tianjin Huanhu Hospital, Tianjin, China, 6Department of Radiology, Tianjin First Central Hospital, School of Medicine, Nankai University, Tianjin, China
    HRMRI determined the cause and length of intracranial large-vessel occlusion, with good agreement with intraoperative angiography.  Pre-canalization intraluminal enhancement was higher among patients who received vessel stenting than in those who did not receive stenting.
    A diagram of acute LVO characteristics and the corresponding typical HRMRI images. HRMRI distinguishes the occluded segments (filled arrowhead) from the slow-flow areas (empty arrowhead). A. ICAS-LVO treated with rescue stenting. Grade 1 enhancement is present on HRMRI, which could reflect higher atherosclerosis plaque percentages compared with those of clots. B. An ICAS-LVO not treated with a stent procedure. Grade 0 enhancement is present on HRMRI, reflecting a higher percentage of clot formation. C. An embolic occlusion treated with a stent retriever.
    A representative case of occluded segment lengths measured with HRMRI in acute MCA occlusion 7 h after the onset of stroke. The occluded segment lengths measured with angiography (A) and HRMRI (Pre- [B1] and postcontrast [B2] imaging) were 19.9 and 16.2 millimeters, respectively. Slow-flow segments were present at the distal and proximal ends of the occluded segment (arrowhead). (C) The time-of-flight image revealed obstruction of the MCA but did not show the occlusion site specifically. (D1) a gross photograph of a clot. (D2) an H&E-stained section of the clot.
  • Characterization of radiological findings in mouse models of cerebral small vessel diseases using multimodal MRI at 14.1 Tesla
    Xiao Gao1, Xiaowei Wang2, Kai Qiao1, Cassandre Labelle-Dumais2, Douglas Gould2, and Myriam M. Chaumeil1
    1Department of Radiology, University of California, San Francisco, San Francisco, CA, United States, 2Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, United States
    Multi-modal MRI at 14.1 Tesla revealed that Col4a1 mutant mouse models faithfully recapitulate the radiological manifestations of cSVDs. Notably, we show that allelic heterogeneity influences disease severity as well as the nature and distribution of lesions.
    (A) All mice were imaged under 1.3-1.8% isoflurane using 4 optimized sequences whose parameter settings have been listed here, with total scan time of ~55 min/animal. (B) An atlas-based imaging data analysis pipeline was used to register mouse brain anatomical and pathological information to the Allen Brain Reference Atlas while K-means algorithm was used to cluster and quantify different lesion types.
    (A) SWI detected hypointense lesions overlooked by T2W imaging. As shown in the pie chart, where the pie radius reflects the total lesion volume per mouse, allelic heterogeneity was shown to influence disease severity and regional distribution of brain regions. Notably, lesions in cortical regions were only observed in the G1038S cohort. (B) The volume of SWI-sensitive lesions was significantly higher in mutant groups (G1038S and G1344D) compared to WT (as expected), and differ between Col4a1 mutant strains.
  • Mechanisms of cerebral ischemic stroke recovery from stem cell derived therapies assessed via MRI at 21.1 T
    Shannon Helsper1,2, Xuegang Yuan1,2, and Samuel Colles Grant1,2
    1National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, United States, 2Chemical & Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL, United States
    23Na chemical shift imaging and relaxation-enhanced MR spectroscopy at 21.1 T provides insight into mechanism of ionic and metabolic homeostasis recovery in cerebral ischemia following hMSC-derived treatments. Methods of EV labeling suitable for in vivo application are demonstrated.
    Fig4. Representative schematic of Na+/K+ ATPase displays the biological explanation for utilizing 23Na MRI to assess cerebral ischemia onset and recovery with treatment. Fractional changes in lesion volume and signal via 23Na CSI provide a sensitive metric to assess treatments.
    Fig1. T2 relaxation images and corresponding rate decays demonstrate SPIO uptake in hMSC EV via sonication and compared to EV exposed to SPIO but not sonication. Lower layers corresponding to supernatant, with this layer in the un-sonicated sample displaying significant diffusion of SPIO into surrounding gel.
  • Mesenchymal Stem Cell Impacts on Cerebral Microstructural Diffusion Recovery After Ischemic Attack
    Frederick A Bagdasarian1,2, Xuegang Yuan1,2, and Samuel Colles Grant1,2
    1National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL, United States, 2Chemical & Biomedical Engineering, FAMU-FSU College of Engineering, Tallahassee, FL, United States
    Human mesenchymal stem cells promote recovery of diffusion metrics after ischemic stroke via DTI, NODDI and DKI analysis. Differences in recovery are evident between white and grey matter.
    Intracellular volume fraction (ICVF) and orientation dispersion index (ODI) for the ipsilateral external capsule and striatum. Representative NODDI maps are provided for a specimen from the hMSC group. * with bracket = significant difference between treatment groups, + = significant difference between treatment group & naïve. #, ¥ and ● = significant difference within group from D3, 7 and 21, respectively. Significance level set at p<0.05.
    Mean, Axial and Radial Diffusivity (MD, AD, RD) and Fractional Isotropy for the ipsilateral external capsule and striatum. Representative DTI maps are provided for a specimen from the hMSC group. * with bracket = significant difference between treatment groups, + = significant difference between treatment group & naïve. #, ¥ and ● = significant difference within group from D3, 7 and 21, respectively. Significance level set at p<0.05.
Back to Top
Digital Poster Session - Perfusion, Diffusion & Other Variables in Stroke Imaging
Neuro
Thursday, 20 May 2021 17:00 - 18:00
  • Perfusion And Permeability Imaging as Diagnostic And Prognostic Biomarkers of Cavernous Angioma with Symptomatic Hemorrhage
    Je Yeong Sone1, Yan Li1,2, Nicholas Hobson1, Sharbel G. Romanos1, Abhinav Srinath1, Seán B. Lyne1, Abdallah Shkoukani1, Julián Carrión-Penagos1, Agnieszka Stadnik1, Kristina Piedad1, Rhonda Lightle1, Thomas Moore1, Ying Li1, Dehua Bi1,3, Timothy Carroll4, Yuan Ji3, Romuald Girard1, and Issam A. Awad1
    1Neurovascular Surgery Program, Section of Neurosurgery, Department of Surgery, University of Chicago Medicine and Biological Sciences, Chicago, IL, United States, 2Bioinformatics Core, Center for Research Informatics, The University of Chicago, Chicago, IL, United States, 3Department of Public Health Sciences, The University of Chicago, Chicago, IL, United States, 4Department of Diagnostic Radiology, University of Chicago Medicine and Biological Sciences, Chicago, IL, United States
    Perfusion derivations helped distinguish CASH 3–12 months prior with 80% sensitivity and 82% specificity. A combination of permeability and perfusion derivations predicted subsequent CA bleeding/growth with 77% sensitivity and 72% specificity.
    Figure 1. The best diagnostic biomarker of CASH 3–12 months prior to DCEQP imaging. (A) Weighted βi coefficients of covariates (all p<0.05) in the perfusion biomarker of CASH 3–12 months prior; error bars are SE. (B) The biomarker distinguished CASH 3–12 months prior (AUC=0.86, p<0.0001) better than entropy (AUC=0.62, p=0.003) or skewness (AUC=0.62, p=0.003) alone. Abbreviations: area under the curve (AUC), cavernous angioma with symptomatic hemorrhage (CASH), dynamic contrast-enhanced quantitative perfusion (DCEQP); standard error (SE).
    Figure 2. The best prognostic biomarker of bleeding/growth within a year after DCEQP imaging. (A) Weighted βi coefficients of covariates (all p<0.05) in the prognostic biomarker; error bars are SE. One outlier (studentized residual>3) was excluded. (B) The biomarker (AUC=0.80, p<0.0001) predicted bleeding/growth better than mean permeability (AUC=0.65, p=0.019) or low-perfusion cluster mean (AUC=0.67, p=0.007) alone. Abbreviations: area under the curve (AUC), dynamic contrast-enhanced quantitative perfusion (DCEQP); standard error (SE).
  • Differences in acute cerebral infarction distribution patterns between young and elderly patients: a MRI study
    Dandan Yang1,2, Yongjun Han3, Dongye Li4, Huiyu Qiao2, Hualu Han2, Rui Shen2, Zihan Ning2, and Xihai Zhao2
    1Capital Medical University, Beijing, China, 2Tsinghua University, Beijing, China, 3Aerospace Center Hospital, Beijing, China, 4Sun Yat-Sen Memorial Hospital, Guangzhou, China
    Of the patients with acute cerebral infarction (ACI), young patients had significantly higher prevalence of multiple ACI lesions in more than one vascular territory and higher percentage of lesions in both anterior and posterior circulations than elderly patients.
    Fig.3. Comparison of acute cerebral infarction patterns between young and elderly patients. The left and right pies above showed the percentage of different distribution patterns of acute cerebral infarction lesions in young and elderly patients, respectively.
    Fig.5. Bar charts of vascular territory patterns of acute cerebral infarction lesions between young and elderly patients. Young patients had significantly higher percentage of lesions in both anterior and posterior circulations than elderly patients.
  • Computer-Aided Detection of Lacunes from FLAIR and T1-MPRAGE MR Images via 3D Multi-Scale Residual Networks
    Mohammed A. Al-masni1, Woo-Ram Kim2, Eung Yeop Kim3, Young Noh4, and Dong-Hyun Kim1
    1Department of Electrical and Electronic Engineering, College of Engineering, Yonsei University, Seoul, Korea, Republic of, 2Neuroscience Research Institute, Gachon University, Incheon, Korea, Republic of, 3Department of Radiology, Gachon University College of Medicine, Gachon University, Incheon, Korea, Republic of, 4Department of Neurology, Gachon University College of Medicine, Gachon University, Incheon, Korea, Republic of

    This study proposes a 3D multi-scale ResNet for lacunes detection. The network conducts multiple parallel paths using different input scales from two image modalities. This enables to learn global features of the lacunes’ anatomical location and hence achieve better detection performance.

    Figure 1. A detailed structure of the proposed 3D multi-scale ResNet.
    Figure 4. Some exemplar results of the proposed 3D multi-scale ResNet. The drawn orange and blue circles refer to the truly detected lacune and non-lacune lesions, respectively.
  • Abnormalities of Cortical Morphology and Structural Covariance Network in Patients With Subacute Basal Ganglia Stroke
    Su Yan1, Guiling Zhang1, Weiyin Vivian Liu2, and Wenzhen Zhu1
    1Radiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China, 2MR Research, GE Healthcare, Beijing, China
    The main findings were that BS could cause cortical atrophy of bilateral frontal and temporal lobes and abnormal structural covariance patterns, featured by decreased global efficiency. In addition, the SCNs of BS also exhibit fragile topological properties in reaction to target attacks.
    Figure 1 | Brain regions show CT differences between BS and HCs. The thinner cortices are observed mainly in the bilateral frontal and temporal lobes. CT, cortical thickness; BS, basal ganglia stroke; HCs, healthy controls; L, left; R, right.
    Figure 3 | Within-group global network measures, and between-group differences of these measures. Clustering coefficient (A,B),Transitivity(C,D) and Global Efficiency (E,F)of the BS and HC networks. The red star indicates the difference between the two groups (B,D,F). BS, basal ganglia stroke; HCs, healthy controls.
  • Relationship between MRI-derived lesion metrics and clinical characteristics in patients with Familial Cerebral Cavernous Malformations
    Sivakami Avadiappan1, Jeffrey Nelson2, Marc Mabray3, Blaine Hart3, Leslie Morrison4, Atif Zafar4, Michel Torbey4, Helen Kim2,5, and Janine Lupo1
    1Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States, 2Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, United States, 3Department of Radiology, University of New Mexico, Albuquerque, NM, United States, 4Department of Neurology, University of New Mexico, Albuquerque, NM, United States, 5Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, United States
    Lesion burden and count of segmented cerebral cavernous malformation lesions were significantly correlated with age and obesity.  Lesion burden in the brainstem and temporal lobes were related to hemorrhagic and seizure events.
    Figure 2. A. 3D visualization of CCM lesions in baseline (pink) and follow-up (green) scans for 2 patients. The lesions that are enlarged in the follow-up scan are highlighted with the blue circle while new lesions are denoted by an arrow. B. The enlargement of the lesion (blue circle) in the follow-up scan compared to the baseline is evident in the consecutive slices from a patient.
    Figure 1. Pipeline for detecting the different sized lesions. (Top) Pipeline for small lesion detection. (Bottom) Pipeline for larger lesion detection. The potential lesion candidates are fed to the GUI where the user labels the lesions.
  • Comparing venous diameter from SWI with ground-truth venous diameter in straight sinus
    Mehdi Zoghinia1, Mohammed Ayoub Alaoui Mhamdi1, and Russell Butler1,2
    1Bishops university, sherbrooke, QC, Canada, 2Diagnostic Radiology, University of Sherbrooke, sherbrooke, QC, Canada
    Comparing venous diameter from SWI with ground-truth venous diameter in straight sinus
    The straight sinus on both SWI and TOF
    diameters
  • ADC and Size Dependent Segmentation Performance using Deep Learning
    Chun-Jung Juan1, Yi-Jui Liu2, Shao-Chieh Lin3, and Yi-Hung Jeng4
    1Department of Medical Imaging, China Medical University Hsinchu Hospital, Hsinchu, Taiwan, 2Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, 3Ph.D. program in Electrical and Communication Engineering, Feng Chia University, Taichung, Taiwan, 4Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, Hsinchu, Taiwan
    Verifies the value of ADC threshold on the performance of the deep learning models in segmenting acute ischemic infarction with increasing the Dice similarity coefficient (DSC).
    (a)Stroke images and labeling region; (b) GT, Prediction and Overlap in each mask.
    The DSCs between the GT and the prediction in different ADC thresholds and different stroke sizes.
  • Cortical microinfarcts on 7T MRI correlate with medial temporal lobe thinning in healthy aging
    Shokufeh Sadaghiani1, M. Dylan Tisdall2, Sandhitsu R. Das1, David A. Wolk1, and John A. Detre1
    1Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States, 2Department of Radiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
    A significant negative correlation was seen between the number of cortical microinfarcts and mean parahippocampal cortical thickness. We also showed that only 26% of total CMIs visible on 7T MRI scans are also visible on 3T scans.
    Figure 1. A. A cortical microinfarct visible on 7T T1-weighted MP2RAGE MRI scan. The CMI is not visible on B. 7T FLAIR MRI scan, C. 3T T1-weighted MRI scan and D. 3T FLAIR MRI scan.
    Table 2. 7T and 3T MRI sequences parameters.
  • 3D high resolution CUBE imaging in evaluating the imaging features of intracranial vasculopathy long after cranial irradiation
    Huimin Mao1, Weiqiang Dou2, Xinyi Wang1, Xinyu Wang1, Kunjian Chen1, and Yu Guo1
    1The First Affiliated Hospital of Shandong First Medical University, Jinan, China, 2GE Healthcare, MR Research China, Beijing, P.R. China, Beijing, China
     Intracranial vasculopathy is not a rare complication after cranial irradiation, even in young patients. Patients after cranial irradiation should be followed up with MR imaging including HR-MRI.
    Figure 1. A 45-year-old man who had undergone radiation therapy after surgical resection of frontal lobe glioma at 26 years old. (A) FLAIR imaging shows peri-lesion white matter lesions. (B) and (C) SWI shows multiple cerebral microbleeds locating widespread the brain. (D) MRA shows multiple intracranial arteries stenosis. (E) Post-contrast 3D T1W HR-MRI shows eccentric plaques with moderate focal enhancement (E, arrow) in right M1 segment of middle cerebral artery. (F) Post-contrast 3D T1W HR-MRI shows prominent circle enhancement in bilateral V4 segment of vertebral arteries.
    Figure 2. A 47-year-old woman who had undergone radiation therapy for pituitary adenoma at 36 years old. Pre-contrast (A) and post-contrast (B) 3D T1W HR-MRI show concentric wall thickening (A, arrow) with prominent circle enhancement (B, arrow) in bilateral V4 segment of vertebral arteries on coronal images. Pre-contrast (C) and post-contrast (D) 3D T1W HR-MRI show track train sign-concentric wall thickening (C, arrow) with prominent homogeneous enhancement (D, arrow) in right V4 segment of vertebral artery on axial images.
  • Neuropathologic correlates of cerebral microbleeds in community-based older adults
    Grant Nikseresht1, Ashish A. Tamhane2, Nazanin Makkinejad3, Carles Javierre-Petit3, Gady Agam1, David A. Bennett2, Julie A. Schneider2, and Konstantinos Arfanakis2,3
    1Department of Computer Science, Illinois Institute of Technology, Chicago, IL, United States, 2Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, United States, 3Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL, United States
    Cerebral microbleeds in community-based older adults are associated with cerebral amyloid angiopathy and arteriolosclerosis. This was true when considering the total number of microbleeds as well as the number of microbleeds in the frontal lobe.
    Figure 2. Neuropathologic characteristics.
    Figure 1. Demographic and clinical characteristics.
  • Personalized MR-derived brain temperature predictions after ischemic stroke – a case study
    Dongsuk Sung1, Peter A. Kottke2, Jason W. Allen1,3,4, Benjamin B. Risk5, Fadi Nahab4, Andrei G. Fedorov2,6, and Candace C. Fleischer1,3,6
    1Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, United States, 2Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, United States, 3Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States, 4Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States, 5Department of Biostatistics and Bioinformatics, Emory University, Atlanta, GA, United States, 6Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, United States
    A personalized MR-derived brain temperature model was developed using patient data. Simulated brain temperatures after right middle cerebral artery occlusion were highest in the ischemic penumbra followed by infarct core, contralateral healthy tissue, and ipsilateral healthy tissue.
    Figure 2. Representative images from a patient with ischemic stroke showing the ability of brain temperature to differentiate regions after ischemic stroke. (A) Tissue regions defined from MR images include infarct core (purple), ischemic penumbra (blue), ipsilateral (green), and contralateral (yellow) healthy tissue; (B) Simulated brain temperature map before occlusion; (C) Simulated brain temperature map after 100% occlusion; (D) Brain temperature difference map (post- minus pre-occlusion). The green boundaries are major continuous regions of ischemic penumbra.
    Figure 3. Predicted brain temperature evolution from onset to 8 hours after right middle cerebral artery occlusion in four regions: ipsilateral healthy tissue (ipsi-healthy), contralateral tissue (contra-healthy), infarct core (infarct), and ischemic penumbra (penumbra), where steady state brain temperatures were 37.21 ˚C, 37.37 ˚C, 37.49 ˚C, and 37.70 ˚C, respectively. These in silico results are consistent with previous in vivo studies and suggest that brain temperature may be used as a predictive biomarker to identify hemodynamically distinct regions.
  • Automated Segmentation of Salvageable Ischemic Brain Tissue using Convolutional Neural Networks with DWI and FLAIR MRI
    Ryan Andrew Rava1,2, Kenneth V. Snyder2,3, Muhammad Waqas2,3, Elad I. Levy2,3, Jason M. Davies2,3, Adnan H. Siddiqui2,3, and Ciprian N. Ionita1,2,3
    1Biomedical Engineering, University at Buffalo, Buffalo, NY, United States, 2Canon Stroke and Vascular Research Center, Buffalo, NY, United States, 3Neurosurgery, University at Buffalo, Buffalo, NY, United States
    Two neural networks were developed to segment penumbra using FLAIR and DWI. Metrics comparing predictions with ground truth penumbra ((dual network, multi-input network): Dice=(0.61, 0.61), PPV=(0.59, 0.64)) indicate a multi-input network is more capable of segmenting penumbra.   
    Figure 3: Top images indicate DWI and FLAIR slices fed into each network to segment the penumbra seen in the bottom images. The dual network prediction indicates the subtraction of FLAIR segmented infarct from DWI segmented ischemic tissue. The multi-input prediction indicates predicted penumbra using both DWI and FLAIR as network input and the red line is an outline of the ground truth penumbra for this slice. Dual and multi-input Dice coefficients for this slice are 0.83 and 0.78 respectively.
    Table 1. Dice Coefficients, sensitivity, positive predictive values, infarct/ischemic tissue/penumbra volume differences, and Spearman correlation coefficients, with 95% confidence intervals, for each network’s segmentation performance of either ischemic tissue (DWI), infarct (FLAIR), or penumbra (Dual Network and Multi-Input).
  • Integrating clinical and imaging features to predict recurrence of cerebrovascular events —— A machine learning study
    mengting wei1, jinhao lv2, liuxian wang2, senhao zhang2, dongshan han2, xinrui wang2, and xin lou2
    1Chinese PLA General Hospital, BeiJing, China, 2Chinese PLA General Hospital, beijing, China
    55 patients were enrolled in this study. After feature selection, 11 variables were included in the study, and the first three variables with greater contribution were HCR, mRS on admission  and diabetes history. FVH score and collateral circulation grade had no significant contribution to recurrent stroke. Then it was divided into model A and model B according to whether the HCR is included or not. The results show that RandomForest and NaiveBayes are the optimal algorithms to identify patients with recurrent cerebrovascular events within one year through machine learning. In addition, there were significant differences between model A and model B.
    Man, 73 years old, Paroxysmal weakness of both lower limbs for 5 months. Figure A ,PWI raw image; Figure B , MRA showed right middle cerebral artery occlusion; Figure C ,Tmax 4s was 238.04ml, Tmax 6s was 113.60ml, Tmax 8s was 29.66ml, Tmax 10s was 4.42ml ( HCR=47.72% ; HIR = 3.89%).
    Comparison between models
  • FLAIR Vascular Hyperintensity May Predict Ischemic Event in Patients with Internal Carotid Artery or Middle Cerebral Artery Occlusion
    Jinhao Lyu1, Mengting Wei1, Xiangbing Bian1, Liuxian Wang1, Senhao Zhang1, Lin Ma1, and Xin Lou1
    1Radiology, Chinese PLA General Hospital, The First Medical Center, Beijing, China
    The presence of Fluid-Attenuated Inversion Recovery vascular hyperintensity (FVH) is able to discriminate symptomatic patients from asymptomatic patients in intracranial internal carotid artery or middle cerebral artery occlusion.
    Figure 4 represents subgroup comparisons of the proportion of absence of FVH between symptomatic occlusion and asymptomatic occlusion. TIA: transit ischemic attack.
    Figure 1 represents insular and M1-M6 regions for Fluid-Attenuated Inversion Recovery vascular hyperintensity Alberta Stroke Program Early Computed Tomography Score (FVH-ASPECTS) assessment. The illustrative case is scored as 3.
  • Optimized Acceleration Factor in Phase Measurement of Brain Deep Veins using SWI with Compressed Sensing
    Jing Yang1, Yanwei Miao1, Yangyingqiu Liu 1, Yu Bing1, Bingbing Gao1, Jiazheng Wang2, Zhiwei Shen2, Ailian Liu1, Qingwei Song1, and Renwang Pu1
    1First Affiliated Hospital of Dalian Medical University, Dalian, China, 2Philips Healthcare, Dalian, China
    The SWI with compressed sensing can reduce the scan time and ensure the image resolution. Meanwhile the optimized acceleration factor and the information of venous oxygen content can be obtained by measuring the phase value in the deep veins.
    Figure 4. It shows the difference of image quality of each vein with different acceleration factors. SV: septal vein, ICV: internal cerebral vein, STV: superior thalamostriate vein, BV: basal vein, DNV: dentate nucleus vein
    Figure 3. It shows the CNR and SNR of the image with the different acceleration factors. SV: septal vein, ICV: internal cerebral vein, STV: superior thalamostriate vein, BV: basal vein, DNV: dentate nucleus vein
  • Effect of Small Vessel Disease Burden on Collateral Perfusion in Symptomatic Large Vessel Stenosis or Occlusion
    Liu-xian Wang1, Dong-shan Han1, Jin-hao Lyu1, and Xin Lou1
    1the First Medical Center, Chinese PLA General Hospital, Beijing, China
    In patients with ICA/MCA severe stenosis/occlusion, those with SVD were older and showed higher incidence of diabetes mellitus. Total SVD burden were not associated with collateral circulation. Perivascular space could affect collaterals.
    Figure 2. Descriptive figures of the change of collateral perfusion and total SVD score along with the interval from symptom onset to imaging (A). Collateral perfusion decreased with the increase of total SVD score (B). Collateral perfusion was defined as (CBF 2.5s minus CBF 1.5s) at lesion side minus (CBF 2.5s minus CBF 1.5s) at normal side. SVD, small vessel disease.
    Figure 3. Cross-sectional correlates of collateral perfusion in symptomatic ICA/MCA severe stenosis or occlusion. ICA, internal carotid artery; MCA, middle cerebral artery; SVD, small vessel disease. a, interval from symptom onset to imaging (days); b, total SVD score. * p < 0.05.
  • Using ASL perfusion images for spatial normalization in a pediatric population with craniosynostosis.
    Catherine A. de Planque1, Henk J. Mutsaerts2, Vera C.W. Keil2, Nicole S. Erler1, Marjolein Dremmen1, Irene M.J. Mathijssen1, and Jan Peter3
    1Erasmus University Medical Center, Rotterdam, Netherlands, 2Amsterdam UMC, Amsterdam, Netherlands, 3Institute of Radiopharmaceutical Cancer Research, Dresden, Germany

     ASL CBF contrast is a viable spatial normalization alternative when structural images are not available or have poor contrast

    Figure 3. An interaction plot from the least square means of the mixed model to predict the TC of different registrations types in control vs patients.
    Figure 2. A boxplot of the tanimoto coefficient of the 4 registration types in patients and controls
  • Can different etiologies provide converging evidence regarding the neural correlates of cognitive performance? Tumor versus stroke
    Eva van Grinsven1, Anouk Smits1, Emma van Kessel1, Mathijs Raemaekers1, Edward de Haan2, Irene Huenges Wajer1,3, Veerle Ruijters1, Marielle Philippens4, Joost Verhoeff4, Pierre Robe1, Tom Snijders1, and Martine van Zandvoort1,3
    1Department of Neurology & Neurosurgery, University Medical Center Utrecht Brain Center, Utrecht University, Utrecht, Netherlands, 2Department of Psychology, University of Amsterdam, Amsterdam, Netherlands, 3Department of Experimental Psychology and Helmholtz Institute, Utrecht University, Utrecht, Netherlands, 4Department of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands
    Despite several differences in the lesion-symptom maps when comparing a tumor and stroke population, our preliminary conclusion is that these two populations can provide complementary information regarding involvement of brain regions for given cognitive tasks.
    Lesion prevalence maps for the tumor (panel A) and stroke group (panel B) are shown superimposed on the MNI brain in radiological view. The colors refer to the number of patients with a lesion at that voxel, with red indicating a higher number of patients. The maximum overlap is 48 and 17 for the tumor and stroke group, respectively. The MNI brain on the right indicates the location of the slices shown in the figure.
    Lesion symptom results for the Boston Naming Task. Lesion overlap indicating those regions in which at least 3 patients had a lesion for the tumor group in blue (N=172), the stroke group in pink (N=103), and overlapping regions shown in the green outlined purple area (Panel A). Voxels significantly associated with performance on this task for the tumor group (red) and stroke group (blue) with the green outline indicating overlapping lesion coverage, as shown in the above panel (Panel B). Maps are shown on the MNI standard brain in radiological view.
  • FREQUENCY DEPENDENT ALTERED FUNCTIONAL CONNECTIVITY OF DECLARATIVE MEMORY NETWORKS IN PATIENTS WITH DURAL ARTERIO-VENOUS FISTULA
    Bejoy Thomas1, Josline Elsa Joseph1, Sabarish S Sekar1, Santhosh Kannath1, and Ramshekhar N Menon2
    1Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, India, 2Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, India
    Dural Arteriovenous fistula (dAVF) causes cognitive deficits and associated memory impairment. Results of this study reveal reduced functional connectivity, in a frequency dependent fashion, among  regions involved in declarative memory functional processing.
    Table 1: rsFC analysis among memory related structures for DP>HC(pFDR<0.01) at different frequency bands.
    Fig1: Weaker rsFC among medial temporal lobe structures in DP than HC
  • Usefulness of low intensity rim sign on DWI for differentiating brain abscess, acute ischemic stroke, and hemorrhagic stroke.
    Takashi Abe1,2, Maki Otomo2, Rintaro Ito1, Rei Nakamichi1, Yumi Abe1, Toshiki Nakane1, Hisashi Kawai1, Toshiaki Taoka1, Shinji Naganawa1, and Masafumi Harada2
    1Nagoya University, Nagoya, Japan, 2Tokushima University, Tokushima, Japan
    In this retrospective image interpretation study showed an accuracy of 70% for differentiating brain abscess, acute ischemic, and hemorrhagic stroke, but by focusing on the low intensity rim, the accuracy increased to 86% (p = 0.025), confirming the importance of low intensity finding on DWI.
    This retrospective study included 14 cases of untreated brain abscess, 20 cases of acute ischemic stroke and 26 cases of acute hemorrhagic stroke. One representative DWI was selected and randomly divided into two groups. Six radiologists (7 to 20 years of experience) reviewed one group consists of 30 DW image before any guidance. The interpretation of another group was carried out after the explanation about the characteristics of low intensity on DWI.
    Data are presented as the; mean (range). Each diagnostic radiologist spent 14.8 min. for the first reading and the accuracy was 70.3%. The reading time after the explanation about the low intensity rim sign was 7.3 min. The accuracy was increased to 85.8 % (p = 0.025).
Back to Top
Digital Poster Session - Vessel Walls, Flow & Angiography in Stroke Imaging
Neuro
Thursday, 20 May 2021 17:00 - 18:00
  • High-Resolution Vessel Wall Imaging: Association of Plaque with Morphological Changes of Lenticulostriate Arteries in SSIs
    Hui Wang1, Xianchang Zhang2, Quanzhi Feng1, Yutian Li1, Jinli Li1, Yujun Wang3, Guangzhao Yang3, Qingle Kong2, Zihao Zhang4, and Tong Han1
    1Radiology, Tianjin Huanhu Hospital, Tianjin, China, 2MR Collaboration, Siemens Healthcare Lid., Beijing, China, 3Radiology, Tongde Hospital of Zhejiang Province, Hangzhou, China, 4State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
    Non-stenotic MCA plaques are effectively detected using HR-VWI. Coupled with a derived biomarker of laterality index, this method may be promising for the identification of BAD in SSIs.  [A1]is? might be?
    Figure 3: Comparison of laterality index (L_index) of LSA morphological parameters between the plaque and non-plaque groups. The L_Index of LSA branches and total length in the plaque group were significantly higher (*, p<0.05) than those in the non-plaque. There was no statistical difference in L_Index of LSA stems.
    Figure1: Plaque group, a 69-year-old female with right lenticulostriate infarction (B) and non-stenotic MCA (A). C: HR-VWI shows the plaque on the upper wall of the MCA-M1 segment (red arrow). LSA skeletons (G-I, from D-E) are shown. The numbers of LSA stems and branches and the total length of LSA on infarcted and healthy sides were 4/6/125 mm and 3/4/89 mm, respectively. The calculated laterality indexes were 0.14/0.30/0.17, respectively.
  • Quantification of hemodynamics of cerebral arteriovenous malformations after stereotactic radiosurgery using 4D Flow MRI
    Shanmukha Srinivas1, Tara Retson1, Aaron Simon2, Marc Alley3, Shreyas Vasanawala3, Jona Hattangadi-Gluth2, Albert Hsiao1, and Nikdokht Farid1
    1Department of Radiology, University of California San Diego, San Diego, CA, United States, 2Department of Radiation Medicine and Applied Sciences, University of California San Diego, San Diego, CA, United States, 3Department of Radiology, Stanford University, Stanford, CA, United States
    Feeding arterial and draining venous blood flow, as measured on 4D flow MRI, decreased in cerebral AVMs after SRS. Pulsatility index increased within the feeding artery. Arterial circumference did not decrease significantly unlike AVM nidus volume and venous circumference.
    Bar graph of total changes in arterial flow, circumference, pulsatility index and AVM volume before and after SRS. Ipsilateral artery flow was significantly greater than contralateral artery flow pre-SRS and decreased significantly post-SRS. Ipsilateral artery circumference was greater than contralateral artery circumference before and after SRS. Ipsilateral artery pulsatility was lower than contralateral artery pulsatility prior to SRS and increased significantly after SRS. Volume significantly decreased after SRS.
    33 year old female with left posterior temporal-occipital AVM treated with a single-stage of SRS (1600 cGy). While T2W imaging (1A, G) and MRA (1B) demonstrate gradual decrease of the nidus from before SRS to 2 years after SRS, 4D Flow (1C, D, F) demonstrates a 61.2% reduction in feeding artery blood flow and 76.5% reduction in draining vein blood flow by 2 months, and normalization of feeding artery blood flow by 2 years. In comparison, there is only 2.3% reduction in feeding artery circumference with a more substantial reduction in draining vein circumference (50.6%) by 2 months (1E).
  • Generating virtual brains for MRI-based 3D cerebral blood flow simulations
    Tamás I. Józsa1, Jan Petr2, Alle Meije Wink3, Frederik Barkhof3, Henk J. M. M. Mutsaerts3, and Stephen J. Payne1
    1Department of Engineering Science, University of Oxford, Oxford, United Kingdom, 2Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany, 3Department of Radiology and Nuclear Medicine, Amsterdam University Medical Center, Amsterdam, Netherlands
    Virtual brains were generated for a mechanistic perfusion simulator. Semi-patient-specific brain meshes were obtained based on T1-weighted MRI scans. Model parameters, such as tissue permeabilities, were optimised to match perfusion statistics obtained from ASL perfusion MRI.
    Figure 1. Schematic drawing of the virtual patient generation pipeline. Solid boxes: input; dash-dotted box: output; dotted boxes: quasi-patient-specific mesh generation; dashed boxes: model parameter tuning.
    Figure 2. (a) Coronal view of the affine registration from the mesh to the patient space, with overlap (green), patient only (yellow) and mesh only (red). (b) Bland-Altman plot of the brain volume corresponding to virtual ($$$V_{vp}$$$) and real patients ($$$V_{rp}$$$). (c) Average (ave) CBF values in virtual ($$$F_{vp}$$$) and real ($$$F_{rp}$$$) patients. (d) Minimum (min) and maximum (max) CBF values in real and virtual patients.
  • Measuring pulse wave velocity in the cerebral arterial tree using 4D flow MRI
    Cecilia Björnfot1, Anders Garpebring1, Sara Qvarlander1, Jan Malm2, Anders Eklund1, and Anders Wåhlin1,3
    1Department of Radiation Sciences, Umeå University, Umeå, Sweden, 2Department of Clinical Sciences, Umeå University, Umeå, Sweden, 3Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
    We present a 4D flow MRI method to estimate pulse wave velocity in the intracranial arterial tree. The method is shown to be stable in an internal consistency test, and of sufficient sensitivity to robustly detect age-related increases in intracranial pulse wave velocity
    Figure 1. (a) Angiographic image and (b) a corresponding centerline representation with calculated vascular depth. (c) The average flow rate waveforms obtained in the most proximal (depth<50mm) as well as in the most distal aspects (depth>250mm) of the visible vasculature. (d) The initial guess, 3rd and 33rd iteration of the estimated arterial waveform obtained from the minimization process. (e) Histogram illustrating the average number of cross sections available as a function of depth in the vascular tree.
  • Integration of high-resolution ultra-high-field 7T magnetic resonance vessel neuroimaging into clinical routine: preliminary results
    Piotr Radojewski1, Arun Joseph2,3,4, Gabriele Bonnano2,3,4, Tom Hilbert5,6,7, Tobias Kober5,7,8, Jan Gralla1, Roland Wiest1, and Pasquale Mordasini1
    1Institute of Diagnostic and Interventional Neuroradiology, Bern University Hospital, Inselspital,, Bern, Switzerland, 22. Advanced Clinical Imaging Technology, Siemens Healthcare AG, Bern, Switzerland, 33. Translational Imaging Center, Sitem-Insel, Bern, Switzerland, 44. Departments of Radiology and Biomedical Research, University of Bern, Bern, Switzerland, 55. Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland, 66. Department of Radiology, , Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland, 77. LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, 86. Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
    Integration of ultra-high-field MR neurovascular vessel imaging at 7 Tesla into clinical routine is feasible providing higher spatial resolution and contrast which may result in an increased diagnostic confidence.
    Scan parameters of T1 SE, T1 SPACE, MPRAGE, ToF, T2 TSE, and SWI protocols used for the vessel wall imaging measurements at 7T.
    Anatomico-morphological characterization. 3D reconstruction of arterial ToF sequence at 3T MRI (left panel) and 7T MRI (right panel) in a case of a suspected UIA. 7T revealed the presence of an infundibulary branch mimicking UIA.
  • Cerebrovascular dual-venc 4D flow MRI: Assessment of arterial pulsatility and resistance measures in intracranial atherosclerotic disease
    Jackson Moore1, Maria Aristova1, Ramez Abdalla1, Ann Ragin1, Eric Russell1, Fan Caprio2, Michael Hurley1, Susanne Schnell3, Sameer A. Ansari1, and Michael Markl1
    1Radiology, Northwestern University, Chicago, IL, United States, 2Neurology, Northwestern University, Chicago, IL, United States, 3Universitaet Greifswald, Greifswald, Germany
    Cerebrovascular dual-venc 4D flow MRI: Comprehensive assessment of arterial pulsatility and resistance measures in intracranial atherosclerotic disease patients
    Figure 1: Analysis workflow. Preprocessing (noise, phase offset, velocity anti-aliasing corrections) and generation of dual-venc phase-contrast MR angiogram workflow not shown. A – TOF MRA DICOMS imported for segmentation. B – 3D segmentation of Circle of Willis from in-house analysis tool. TOF is registered with PC MRA to extract 4D flow information. C – Vessel branch centerline extraction for further analysis. D – Placement of analysis planes along example vessel every 1 mm. E – View of single plane ROI delineating vessel contours, velocity map, and velocity vector profile.
    Figure 2: Asymmetry index analysis results for PI and RI in ICAD patients with symptomatic MCA vessels. PI and RI comparisons to controls showed statistical significance (p < 0.05).
  • Reproducibility of quantitative measures of intracranial arterial geometry: dependence on sequence and scanner platform differences
    Niranjan Balu1, Wenjin Liu1, Zhensen Chen1, Anders Gould1, Dan S Hippe1, Li Chen1, Binbin Sui2, Mi Shen2, Peiyi Gao2, Thomas S Hatsukami1, and Chun Yuan1
    1Radiology, University of Washington, Seattle, WA, United States, 2Beijing Tiantan Hospital, Beijing, China
    Dependence of measurement reproducibility of intracranial distal vessel length on TOF-MRA on protocol and scanner platform variation was investigated.  High reproducibility was achieved suggesting feasibility of quantitative vessel length measurements for multi-platform studies.
    Figure 1: Segmented arteries by iCafe from two Philips 3T TOF-MRA (S/I FOV 7.2cm) 2 weeks apart. The different colors indicate different arteries as denoted by the labels (Left (denoted by suffix L) and right (denoted by suffix R) sided ICA- internal carotid artery, M1/A2 – Middle cerebral artery M1, M2 branches, A1/A2 - Anterior cerebral artery A1, A2 branches), BA – Basilar artery, P1/P2 – posterior cerebral artery P1, P2 branches, PComm – posterior communicating artery). Quantitative artery length measurements can be derived based on the centerlines from these iCafe segmentations.
    Table 2. Comparison of scan-rescan reproducibility based on different protocol parameters on Siemens 3T
  • Preliminary study on plaque characteristics of intracranial artery atherosclerotic stroke in young adults
    Ling Li1, Xiao Ling Zhang1, Min Tang1, Xue jiao Yan1, Nian E Ma1, Xiao Yan Lei1, Xin Zhang1, Juan Li1, and Kai Ai2
    1Department of MRI, Shaanxi Provincial People's Hospital, Xi'an, China, 2Philips Healthcare, Xi'an, China
    We found some differences in atherosclerotic plaque characteristics and clinical data between young and old patients, which is helpful to explore the potential pathophysiological mechanism of atherosclerotic stroke plaque formation in young people.
    Figure 1. Measurements of vessel plaque characteristics. In a young patient (31 years old ) with an infarction in the left hemisphere (A), left MCA stenosis (B, arrowhead) was observed, A eccentric plaque in vessel wall (C, arrowhead) on high-resolution MRI was measured. In a old patient (68 years old ) with an infarction in the left basal ganglia (D), left MCA stenosis (E, arrowhead) was observed, A diffuse plaque in vessel wall (F, arrowhead) on high-resolution MRI was measured.
    The vessel wall characteristics of plaque were summarized in Table 1. The demographic data were summarized in Table 2. P < 0.05 indicates a significant difference.
  • Ultrahigh Resolution 3T Clinical Black-blood Angiography: A new imaging biomarker of aneurysm occlusion following endovascular therapy
    Adam E. Goldman-Yassen1, Eytan Raz2, Anna Derman2, Ahrya Derakhshani3, and Seena Dehkharghani2,4
    1Department of Radiology, Children's Healthcare of Atlanta, Atlanta, GA, United States, 2Department of Radiology, New York University Langone Medical Center, New York, NY, United States, 3Department of Radiology, UCLA Health, Los Angeles, CA, United States, 4Department of Neurology, New York University Langone Medical Center, New York, NY, United States
    High-resolution black-blood vessel wall imaging optimized with robust flow suppression offers reproducible, reliable, and non-invasive evaluation of flow diversion treated aneurysms, with superior overall classification accuracy relative to conventional TOF or dynamic MRA.
    DSA (A) and TOF MRA (B) show an aneurysm at the left SCA and PCA junction (blue circle). Followup DSA (C) after basilar/left PCA flow-diverting stent placement demonstrates complete occlusion. MRA demonstrates questionable flow-related enhancement not easily discriminated from T1 shine through from organizing clot (D). Pre (E) and postcontrast (F) VWI demonstrate preserved high-resolution black blood angiography across the stented PCA segment (dashed arrow). Organizing clot within the aneurysm sac (orange circle) is noted, likely fed through a vasa vasorum, without flow voids.
    Comparison of patient characteristics and vessel wall imaging findings between subjects with and without complete aneurysm occlusion of followup angiogram after flow diverter placement.
  • Material investigation for in vitro aneurysm flow model that mimics the arterial vessel and examining the flow in rigid wall model using 4D Flow MRI
    Isil Unal1, Duygu Dengiz2, Eckhard Quandt2, Mona Salehi Ravesh1, Jan-Bernd Hövener3, Mariya Pravdivtseva1, and Olav Jansen1
    1Department for Radiology and Neuroradiology, University Hospital Schleswig-Holstein, Campus Kiel, Germany, Kiel, Germany, 2Institute for Materials Science, Faculty of Engineering, University of Kiel, Germany., Kiel, Germany, 3Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Kiel, Germany
    The models produced using various resins were effective in obtaining a value close to the elastic modulus of the real brain artery. Thus, more realistic results can be obtained in in vitro flow measurements usind 4D Flow MRI. 
    Figure 2. Illustration of tensile test setup (a), The stress-strain data (blue) was fitted with a linear function (black) to obtain the elastic module (material-2 at a = 0°) as a result of 0.50 MPa.
    Figure 4. Elastic modulus of samples with respech to the real artery. Elastic modulus of all samples (b). As shown in the graph and the table to the graph elastic modulus values are in the range except material-2/Sample-1/45⁰; material-2/Sample 1 and 3/90⁰.
  • The application of High-Resolution Vessel Wall MRI(HR-VW-MRI) in determining the stability of intracranial MCA and BA plaques
    Hongwei Zhou1, Derui Kong1, and Tianjing Zhang2
    1The First Hospital of JiLin University, Changchun City,Jilin Province, China, 2Philips healthcare, Guangzhou City,Guangdong Province, China
    High-resolution vessel wall MR imaging(HR-VW-MRI) method could demonstrate the abnormality of the vessel wall .It could also potentially evaluate the stability of the intracranial artery.

    Figure 2:Hyper signal could be seen in the right corona radiata,so the MCA plaque is a symptomatic plaque(A).

    MRA showed the mild stenosis of the right middle cerebral artery.(B)

    The maximum wall thickness as measured using the MRI-PlaqueView software at the leision slice of the right middle artery was 0.81 mm.(C)

    The plaque distribution range measured using RadiAnt DICOM Viewer software at the leison slice of the right middle artery was 116°.(D)

    Figure 3:Hyper signal could be seen in the left cerebral peduncle, so the plaque was a symptomatic plaque(A).

    The plaque distribution range at the leision slice of BA was 136°.(B)

    The maximum wall thickness and the minimum wall thickness for the lesion slice were 2.07 mm and 0.41 mmrespectively (C and D)

  • Significant lower WSS and higher OSI on enhanced wall area of intracranial aneurysm
    Mingzhu Fu1, Shuo Chen1, Miaoqi Zhang1, and Rui Li1
    1Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China
    Relationship between aneurysm wall enhancement and distribution of WSS and OSI from pixel-wise perspective based on the self-control of aneurysm was studied. Statistics indicated that enhanced wall area of intracranial aneurysm had significant lower WSS and higher OSI.
    Figure.1 A, MRA. B, Enhancement on aneurysm (large arrow) and pituitary infundibulum (small arrow). C, Corresponding image of aneurysm on MR-VW postgadolinium T1WI (left), TOF (inset, middle) and 4D Flow MRI (inset, right). D, Normal vectors of vessel wall. E, Joint visualization of MR-VW postgadolinium T1WI and vessel model. F, Distribution of enhancement values on low enhanced area (black) and high enhanced area (polychrome). G, WSS distribution. H, OSI distribution. The high enhanced area (large arrow) had lower WSS and higher OSI than low enhanced area (small arrow).
    Figure.2 Scatter plot of distributions of WSS (A) and OSI (B) on low enhanced area (blue dots) and high enhanced area (red dots) of aneurysm located at the end of M1 of middle cerebral artery.
  • Silent MR Angiography for the Depiction of cerebral arteriovenous Malformations: A Comparison of Techniques
    Chunxue Wu1, Mengqi Dong1, Tao Hong2, Hongqi Zhang1, and Jie Lu1
    1Xuanwu Hospital Capital Medical University, Beijing, China, 22030921@qq.com, Beijing, China
    Digital subtraction angiography (DSA) is the golden standard of radiological technique for diagnosis and treatment evaluation of cerebral arteriovenous malformations (CAVMs). However, DSA is invasive and ionizing radiative. Silent MRA, which combines arterial spin labeling (ASL) and an ultrashort time echo (UTE), is used for CAVM structure visualization. The silent MRA is superior to TOF-MRA and enables the same Spetzler-Martin classification of cerebral AVM as that at DSA.
    Figure 1: DSA, silent and TOF MRA images of a 14-year-old male patient with a left frontal CAVM. DSA anterior(a) and lateral (b) projection from the left internal carotid artery reveals AVM nidus (*) fed primarily by the left anterior and middle cerebral artery (arrowhead) and its drainer (arrow). The nidus (asterisk) feeders (arrowhead) and drainer (arrow) are better delineated on Silent MRA images (c,d) than the TOF MRA ones (e,f ).
    Figure 2: DSA , silent and TOF MRA images of a 33-year-old female patient with a right basal ganglia CAVM. DSA anterior(a) and lateral (b) projection from the right internal carotid artery reveals AVM nidus (*) fed primarily by the right anterior and middle cerebral artery (arrowhead) and its deep venous drainer (arrow). The nidus (asterisk) and drainer (arrow) are better delineated on Silent MRA images (c,d) than the TOF MRA ones (e,f )
  • Comparisons of high-resolution intracranial vessel wall MRI findings in different types of middle cerebral artery territory infarction
    So Yeon Won1, Jihoon Cha1, Hyun Seok Choi1, Young Dae Kim2, Hyo Suk Nam2, Ji Hoe Heo2, and Seung-Koo Lee1
    1Radiology, Severance Hospital, Seoul, Korea, Republic of, 2Neurology, Severance Hospital, Seoul, Korea, Republic of
    In patients with BOD, the plaque margin was closer to perforator orifice with less stenosis and enhancement than patients with artery to artery embolism.
    Figure 2. Representative case with BOD. A. Longitudinal plane of MCA with fusion image (PD+T1CE). B. Cross-sectional image where perforator arouses. Perforator (red arrow), plaque (white arrow) C. Plaque distribution was expressed as an angle. Perforator was located at margin of the plaque.
    Figure 1.Diagram of patient selection.
  • Application of 3D vessel wall high-resolution MR(3D VW-MR) imaging in Primary Angiitis of the Central Nervous System
    Hongwei Zhou1, Derui Kong1, and Tianjing Zhang2
    1The First Hospital of JiLin University, Changchun City,Jilin Province, China, 2Philips healthcare, Guangzhou City,Guangdong Province, China
    The purpose of our study was to summarize the typical imaging performance of PACNS and evaluate the value of 3D- VW-MRI sequence in demonstrating the detailed information in detection, diagnosis, evaluation, and follow-up for PACNS.
    Figure 1:(A): MRA demonstrated smooth wall and no obvious stenosis. (B): Head MRI showed abnormal signals in the left oculomotor nucleus. (C-E): 3D VW-MRI showed unevenly thickening and abnormal enhancement of basilar artery,bilateral posterior cerebral artery and middle cerebral artery. (F-G):Curved plannar reconstruction by 3D-VW-MRI showed the left and right middle cerebral artery had no apparent enhancement after 4 months therapy, while the vessel wall was getting thickness.
    Figure 2:(A):MRA revealed multiple stenosis of both the anterior circulation and the posterior circulation. (B~H)3D VW-MRI showed smooth, concentric arterial wall thickening and enhancement of bilateral vertebral artery, the left internal carotid artery and middle cerebral artery.
  • Application Value of High-resolution Vessel Wall Imaging for Quantitative Analysis of Lipid-rich Necrotic
    Mengjiao Wei1, Yang Gao1, Qiong Wu1, Shaoyu Wang2, and Huapeng Zhang2
    1Department of Radiology, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, China, 2MR Scientific Marketing, Siemens Healthineers, Shanghai, China
    The maximum wall thickness, the maximum lipid-rich necrotic core percentage and the CAS score can accurately predict the risk of stroke and provide evidence for diagnosis and treatment.
    Figure 1. Typical images of the right internal carotid artery(R-ICA). (A)(B)(D)HR-VWI shows an isointensity plaque on T1WI, T2WI and TOF sequences on the right internal carotid artery wall (arrow) without postgadolinium enhancement(E). (C)3D fusion image shows that maximum lipid-rich necrotic core percentage > 40%. (F)Pathological result shows that a large amount of lipid components in the plaque.
  • Evaluation of registration accuracy for cerebral vessel on pre- and postcontrast T1 black blood images by Elastix
    Wei Qiu1, Hanyu Wei1, Shuo Chen1, and Rui Li1
    1Center for Biomedical Image Research, Department of Medicine, Tsinghua University, Beijing, China
    Using Elastix to register pre- and postcontrast T1 brain images is reproducible and effective and helpful to get some contrast information automatically.
    Figure 1. A schematic diagram of the selected areas(yellow) of part 1(left, Random irregular regions) and part 2(right, axial direction of special vessels).
    Figure 2. The registration results from representative slices are shown.
  • The Impact of Acceleration Factors of  Compressed Sensing on the Image Quality of 3D-TOF-MRA for Cervical Vessels
    Haonan Zhang1, Qingwei Song1, Jiazheng Wang2, Peng Sun2, Renwang Wang1, Nan Zhang1, and Ailian Liu1
    1Department of Radiology, the First Affiliated Hospital of Dalian Medical University, Dalian, China, 2PHILIPS——Philips Healthcare, beijing, China
    In this study, we demonstrated that a large CS acceleration factor will degrade the image quality of 3D-TOF-MRA for cervical vessels significantly. CS factor of 6 is recommended for the compromise between imaging time and image quality of clinical 3D-TOF carotid MRA.
    Figure 2. Reconstruction of cervical vessels, from left to right: default, CS4-CS8.
    Figure 1. Male, 68 years old. Use ROI to measure SI and SD on both sides. The measured left blood vessel SI value was 2485.45, muscle SI value was 523.2, and muscle SD value was 24.3. The measured right blood vessel SI value was 2152.71, muscle SI value 566.59, and muscle SD value 20.49. The largest and smallest diameters of internal carotid arteries on both sides were measured. The largest diameter measured on the right side is 7.13mm, and the smallest diameter is 6.25mm. The maximum diameter on the left is 6.76mm and the minimum diameter is 6.25mm.
  • Investigation into the Cerebrovascular Effects of Gender Affirming Therapy in Transgender Men using TOF-MRA and pCASL
    Samantha Cote1, Reihaneh Forouhandehpour1, Etienne Croteau1, Diane Rottembourg2, Jean-Francois Lepage2, and Kevin Whittingstall3
    1Département de médecine nucléaire et radiobiologie, Université de Sherbrooke, Sherbrooke, QC, Canada, 2Département de pédiatrie, Université de Sherbrooke, Sherbrooke, QC, Canada, 3Département de radiologie diagnostique, Université de Sherbrooke, Sherbrooke, QC, Canada
    In the present study we observed a decrease in whole brain CBF accompanied by a decrease in arterial diameters after gender affirming therapy in transgender men that appears proportional to their change in serum testosterone

    A) Whole-brain CBF pre and post GAHT treatment in participant 1.

    B) Whole-brain CBF pre and post GAHT treatment in participant 2.

    C) Percent change in average whole-brain CBF. Note that percent change in CBF appears to be of the same magnitude as the change in Serum T shown in D.

    D) Percent change in Serum T.

    A) 3D projection of segmented vascular tree, with diameter values in participant 1. White arrows indicate regions where TOF-Voxels decreased after GAHT.

    B) 3D projection of segmented vascular tree, with diameter values in participant 2. White arrows indicate regions where TOF-Voxels decreased after GAHT.

    C) Percent change of TOF-Voxels. The decrease of TOF-Voxels is of the same magnitude as the decrease in CBF.

    D) Change in arterial diameter in small arteries. Note that across all groups of small vessels there was a decrease in the number of voxels with in each diameter class.

  • Type and Time of Dialysis Are Independent Indicators for Carotid Atherosclerosis in End-stage Renal Disease Patients on Dialysis
    Yuze Li1, Chunmiao Chen2, Yajie Wang1, Jie Li2, Xiaoli Sun2, Shuiwei Xia2, Lie Jin2, Yani Ye2, Jiansong Ji2, and Huijun Chen1
    1Center for Biomedical Imaging Research, Medical School, Tsinghua University, Beijing, China, 2The Central Hospital of Zhejiang Lishui, Lishui, China
    The vessel wall characteristics of carotid artery was measured on T1w, T2w and SNAP images in end-stage renal disease patients on dialysis. The presence of plaque was found to be significantly and independently associated with the dialysis type and time on dialysis.
    Table 4. Univariate and multivariate logistic regression of clinical factors associated with the presence of plaque
    Figure 1. (A) The carotid vessel wall images of a 62-year-old male patient with 6 months of hemodialysis. (B)The carotid vessel wall images of a 58-year-old male patient with 62 months of hemodialysis;