Velocity-selective arterial spin labeling.
In pathologies in which slow or collateral flow conditions may exist, conventional arterial spin labeling (ASL) methods that apply magnetic tags based on the location of arterial spins may not provide robust measures of cerebral blood flow (CBF), as the transit delay for the delivery of blood to target tissues may far exceed the relaxation time of the tag. Here we describe current methods for ASL with velocity-selective (VS) tags (termed VSASL) that do not require spatial selectivity and can thus provide quantitative measures of CBF under slow and collateral flow conditions. The implementation of a robust multislice VSASL technique is described in detail, and data obtained with this technique are compared with those obtained with conventional pulsed ASL (PASL). The technical considerations described here include the design of VS pulses, background suppression, anisotropy with respect to velocity-encoding directions, and CBF quantitation issues.
Wong
Eric C
EC
Department of Radiology, University of California-San Diego, La Jolla, 92093, USA. ecwong@ucsd.edu
Cronin
Matthew
M
Wu
Wen-Chau
WC
Inglis
Ben
B
Frank
Lawrence R
LR
Liu
Thomas T
TT
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D001921:Brain / Q000033:anatomy & histology / Q000098:blood supply* / Q000502:physiology*; D002536:Cerebral Arteries / Q000033:anatomy & histology / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D012212:Rheology / Q000379:methods; D013113:Spin Labels
D013113:Spin Labels