Visualizing artery‐specific blood flow patterns above the circle of Willis with vessel‐encoded arterial spin labeling

• Published in: Magnetic resonance in medicine Vol. 81; no. 3; pp. 1595 - 1604
• Main Authors: Okell, Thomas W., Garcia, Meritxell, Chappell, Michael A., Byrne, James V., Jezzard, Peter
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.03.2019; John Wiley and Sons Inc
• Subjects: Adult; Angiography; Arteries; Arteries - diagnostic imaging; arteriovenous malformation; Arteriovenous Malformations - diagnostic imaging; Automation; Blood flow; Blood Flow Velocity; Brain; Brain - blood supply; Brain - diagnostic imaging; Branches; Cerebrovascular Circulation; Circle of Willis - diagnostic imaging; Coding; dynamic angiography; Feasibility; Feasibility studies; Female; Flow distribution; Full Papers—Imaging Methodology; Healthy Volunteers; Hemodynamics; Humans; Image Enhancement - methods; Image Processing, Computer-Assisted; Imaging, Three-Dimensional - methods; Labeling; Lesions; Male; Medical imaging; Middle Aged; Neuroimaging; Perfusion; Plant tissues; Signal-To-Noise Ratio; Spin labeling; Spin Labels; Territory; vascular territory imaging; Veins & arteries; vessel‐encoded pseudocontinuous arterial spin labeling (VEPCASL); vessel‐selective; arteriovenous malformation; vessel-encoded pseudocontinuous arterial spin labeling (VEPCASL); vessel-selective; dynamic angiography; vascular territory imaging
• ISSN: 0740-3194; 1522-2594
• DOI: 10.1002/mrm.27507

Purpose To establish the feasibility of using vessel‐encoded pseudocontinuous arterial spin labeling (VEPCASL) for noninvasive vascular territory imaging (VTI) and artery‐specific dynamic angiography of a large number of arterial branches above the circle of Willis within a clinically feasible scan time. Methods 3D time‐of‐flight angiography was used to select a labeling plane and establish 7 pairs of encoding cycles. These were used for VEPCASL VTI and dynamic 2D angiography (8 min and 3 min acquisition times, respectively) in healthy volunteers, allowing the separation of signals arising from 13 arterial branches (including extracranial arteries) in postprocessing. To demonstrate the clinical potential of this approach, VEPCASL angiography was also applied in 5 patients with brain arteriovenous malformation (AVM). Results In healthy volunteers, the artery‐specific filling of the vascular tree and resulting perfusion territories were well depicted. SNRs were approximately 5 times higher than those achievable with single‐artery selective methods. Blood supply to the AVMs was well visualized in all cases, showing the main feeding arteries and venous drainage. Conclusions VEPCASL is a highly efficient method for both VTI and dynamic angiography of a large number of arterial branches, providing a comprehensive picture of vascular flow patterns and the effect on downstream tissue perfusion within an acceptable scan time. Automation of labeling plane and vessel‐encoding selection would improve robustness and efficiency, and further refinement could allow quantitative blood flow measurements to be obtained. This technique shows promise for visualizing the blood supply to lesions and collateral flow patterns.