ISMRM 21st Annual Meeting & Exhibition 20-26 April 2013 Salt Lake City, Utah, USA

Advanced Neurovascular MRA
Thursday 25 April 2013
Room 255 EF  10:30 - 12:30 Moderators: Brian K. Rutt, David Saloner

10:30 0622.   Cerebrospinal Arterial and Venous Blood Flow Variability Assessed with 4D Flow MRI
Eric Mathew Schrauben1, Kevin M. Johnson1, Jason Huston2, Aaron Field2, and Oliver Wieben1,2
1Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, 2Radiology, University of Wisconsin - Madison, Madison, WI, United States

The testing of the CCSVI hypothesis necessitates reproducible flow quantification in the head and neck veins, which have shown to be affected by many physiological variables. This study demonstrates the use of PC VIPR for testing reproducibility in the cerebrospinal veins.

10:42 0623.   
Comparison of Vessel-Encoded Arterial Spin Labeling Dynamic Angiography with X-Ray Digital Subtraction Angiography in Patients with Vertebrobasilar Disease
Thomas W. Okell1, Ursula G. Schulz2, Michael A. Chappell1,3, Meritxell Garcia4, Wilhelm Küker2, and Peter Jezzard1
1FMRIB Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 2Stroke Prevention Research Unit, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom, 3IBME, Department of Engineering, University of Oxford, Oxford, United Kingdom, 4Division of Diagnostic & Interventional Neuroradiology, Department of Radiology & Nuclear Medicine, University of Basel Hospital, Basel, Switzerland

Vessel-encoded pseudocontinuous arterial spin labelling (VEPCASL) dynamic angiography provides vessel-selective information similar to x-ray digital subtraction angiography (DSA) non-invasively and without contrast agent. Two interventional neuroradiologists performed scoring of images from the two modalities in patients with vertebrobasilar disease. Reasonable agreement was found for the assessment of collateral flow, proximal artery flow and late filling and good agreement for assessing vertebral artery dominance. Some variation in the scores was present due to the subjective nature of the scoring, but x-ray DSA may have overestimated flow in stenosed vessels during the contrast injection due to the applied pressure.

10:54 0624.   Time of Arrival Enhanced 4D MRA
Yijing Wu1, Jane Maksimovic2, Patrick Turski2, and Charles A. Mistretta3
1Medical Physics, University of Wisconsin, Madison, WI, United States, 2Radiology, University of Wisconsin, Madison, WI, United States, 3Medical Physics and Radiology, University of Wisconsin, Madison, WI, United States

High resolution time-resolved contrast-enhanced MRA using hybrid HYPR reconstruction (4D Hybrid HYPR MRA) is able to provide sub-second temporal resolution and sub-millimeter isotropic spatial resolution with whole brain coverage. However, due to the significant dispersion of the contrast bolus resulting from the circulation through the heart and lungs after the venous injection contrast, it is very challenge to achieve similar temporal effects as using the x-ray DSA. Time-of-arrival (TOA) map can be estimated from the 4D MRA dataset and provide quantitative description of contrast material arrival time in each voxel. In this project, we propose to combine the TOA map with the Hybrid HYPR MRA to further enhance the visualization of contrast kinetics and display “DSA” like bolus tracing with intravenous injection.

11:06 0625.   
Non-Contrast-Enhanced High-Temporal-Resolution 4D MRA with an Acquisition Window Covering Two Cardiac Cycles: Assessment of Arteriovenous Malformations in the Brain
Hélène Raoult1,2, Elise Bannier2, Benjamin Robert3, Peter Schmitt4, and Jean-Yves Gauvrit1,2
1Neuroradiology, University Hospital, Rennes, France, 2Unité VISAGES U746 INSERM-INRIA, IRISA UMR CNRS 6074, University of Rennes, Rennes, France, 3Siemens S.A.S., Saint Denis, France, Metropolitan, 4Siemens AG, MR Application & Workflow Development, Erlangen, Germany

The present work applies a bSSFP NCE 4D MRA sequence with a temporal window covering two cardiac cycles (2 RR intervals) and assesses quality and diagnosis performance in ten patients with arteriovenous malformation. The sequence achieves high temporal and spatial resolution, yielding high-quality images with improved depiction of arterial feeding, nidus size and venous drainage compared with DSA. The venous drainage was better depicted with 2-RR than with 1-RR NCE MRA, improving AVM hemorrhagic risk evaluation, without any trade-off for the nidus delineation quality.

11:18 0626.   HYPR FLOW Dynamic MR Angiography in Intracrianal Arterio-Venous Malformations: Comparison to TRICKS MR Angiography and Catheter Angiography.
Raphaël Dautry1, Pauline Roca1, Myriam Edjlali-Goujon1, Cécile Rabrait2, Kevin M. Johnson3, Yijing Wu3, Olivier Naggara1, Christine Rodriguez1, Fawaz Alshareef1, Olivier Wieben3, Catherine Oppenheim1, and Jean-François Meder1
1Neuroradiology, Centre hospitalier Sainte Anne, Paris, France, 2GE healthcare, Vélizy Villacoublay, France, 3Departments of Medical Physics and Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States

Non-invasive MR Angiography (MRA) is routinely used for the characterization of cerebral Arterio-Venous Malformations (AVMs), but the gold-standard imaging technique remains catheter angiography. We compared HYPR FLOW, a novel MRA method that provides sub-millimeter spatial resolution and sub-second temporal resolution, to TRICKS MRA for the characterization of AVMs, using angiography as a reference. HYPR FLOW was superior to TRICKS for the analysis of vascular enhancement kinetics and for the characterization of several AVMs key parameters, including venous drainage, arterial feeders and venous ectasia. HYPR FLOW could replace TRICKS or other MRA techniques for the characterization and follow-up of AVMs.

11:30 0627.   
Natural Course of Intracranial Vessel Wall Lesions in Stroke- And TIA Patients at 7.0 Tesla MRI
Anja G. van der Kolk1, Jaco J.M. Zwanenburg1, Manon Brundel2, Geert Jan Biessels2, Fredy Visser1,3, Peter R. Luijten1, and Jeroen Hendrikse1
1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands, 2Department of Neurology, University Medical Center Utrecht, Utrecht, Netherlands, 3Philips Healthcare, Best, Netherlands

A substantial percentage of patients with cerebrovascular disease have been shown to have intracranial vessel wall lesions. It is, however, not clear whether these are stable lesions, or changing over time. To assess the natural course of these lesions, 35 ischemic stroke- or TIA-patients with an Magnetization Preparation Inversion Recovery (MPIR)-TSE scan at 7.0 Tesla within 1 week and 1 month after the ischemic event were included. The majority of patients had stable lesions, indicating a prolonged cerebral atherosclerotic process. The used MPIR-TSE vessel wall sequence at 7.0 Tesla may allow for assessment over time of (progressive) intracranial atherosclerotic plaques.

11:42 0628.   7 Tesla MRA Enables Differentiation Between Intracranial Aneurysms and Infundibula
Maarten J. Versluis1,2, Matthias J.P. van Osch1,2, Marianne A.A. van Walderveen1, and Marieke J.H. Wermer3
1Radiology, Leiden University Medical Center, Leiden, Netherlands, 2C.J. Gorter Center for High FIeld MRI, Leiden University Medical Center, Leiden, Netherlands, 3Neurology, Leiden University Medical Center, Leiden, Netherlands

In 5 patients in whom a small vascular lesion was detected at 1.5T or 3T, suspect for an aneurysm or infundibulum underwent an additional 7T MR. In all patients we were able to confirm the presence of an infundibulum and exclude an aneurysm based on the 7T images. Our data suggest that the high resolution of 7T TOF MRI is a useful new non-invasive tool that can help in discriminating true intracranial aneurysms from infundibula and can prevent excessive repeated imaging and invasive techniques and exposure to radiation in patients with small vascular lesions

11:54 0629.   Cerebral Aneurysm Wall Permeability, a New Parameter for Assessing Ruptue Risk
Parmede Vakil1, Sameer A. Ansari2, Marie Wasliewski2, Susanne Schnell2, Hunt Batjer3, Christopher S. Eddleman3, Bernard R. Bendok4, Michael Markl2, and Timothy J. Carroll1
1Biomedical Engineering and Radiology, Northwestern University, Chicago, IL, United States, 2Radiology, Northwestern University, Chicago, IL, United States, 3Neurosurgery, University of Texas Southwestern, Dallas, Texas, United States, 4Neurosurgery, Northwestern University, Chicago, IL, United States

Cerebral Aneurysms pose a significant risk to the population at large with over 30,000 ruptures each year. Geometric shape indices and hemodynamic studies of blood velocity and wall shear stress provide non-invasive and quantifiable imaging metrics for assessing rupture risk. We have developed a model for studying wall permeability in cerebral aneurysms using DCE-MRI derived kinetic modeling of contrast agent leakage based on Tofts’ classic model. We have found that the derived non-invasive metrics Ktrans and leakage volume space which describe aneurysm “leakiness” may also be used for rupture risk assessment.

12:06 0630.   Comprehensive Vessel Wall Imaging for Concomitant Extracranial and Intracranial Atherosclerotic Plaques in Symptomatic Patients Using Fast 3D Multicontrast Black-Blood MR Imaging Sequences -permission withheld
Xihai Zhao1, Rui Li1, Jinnan Wang2, Le He1, Zechen Zhou1, Xiping Gong3, Donghua Mi3, Xingquan Zhao3, and Chun Yuan1,4
1Center for Biomecial Imaging research & Department of Biomedical Engineering, Tsinghua University, Beijing, China, 22. Philips Research North America, Briarcliff Manor, NY, United States,3Department of Neurology, Tiantan Hospital, Capical Medical University, Beijing, China, 4Department of Radiology, University of Washington, Seattle, WA, United States

Angiography studies have shown that intracranial and extracranial concomitant atherosclerotic diseases are common in stroke patients. However, stenosis-based approaches underestimate disease severity due to the phenomenon of positive remodeling. Recently proposed 3D vessel wall imaging sequences, such as MERGE, VISTA, and SNAP, may have the potential to perform comprehensive imaging for detection of concomitant plaques at intracranial and extracranial circulations. This study sought to assess neurovascular concomitant atherosclerosis using 3D multicontrast black-blood imaging sequences in symptomatic patients. We found that stroke patients frequently developed concomitant intracranial and extracranial atherosclerosis much more commonly than literature reports (74.1% vs. 43%).

12:18 0631.   Wall Shear Stress Distribution in Carotid Artery Stenosis: Changes Pre- And Post-Intervention by Carotid Endarterectomy
Michael Markl1, Sebastian Berg2, Alex J. Barker1, J Schöllhorn2, Martin Schumacher2, Cornelius Weiller2, and Andreas Harloff2
1Northwestern University, Chicago, IL, United States, 2University of Freiburg, Freiburg, Germany

Low wall shear stress (WSS) and high oscillatory shear index (OSI) have been linked to the development of atherosclerosis. The purpose of this study was to investigate the impact of carotid endarterectomy on the in-vivo WSS and OSI distribution in the carotid bifurcation. In 20 patients, 4D flow MRI was able to selectively quantify regional 3D hemodynamics in patients before and after intervention for high-grade ICA stenosis. Plaque removals lead to significant reductions of WSS and OSI in the ICA while wall parameters in the CCA and ECA remained largely unchanged demonstrating a localized impact of endarterectomy on carotid hemodynamics.