title: Continuous flow-driven inversion for arterial spin labeling using pulsed radio frequency and gradient fields.
abstract: Continuous labeling by flow-driven adiabatic inversion is advantageous for arterial spin labeling (ASL) perfusion studies, but details of the implementation, including inefficiency, magnetization transfer, and limited support for continuous-mode operation on clinical scanners, have restricted the benefits of this approach. Here a new approach to continuous labeling that employs rapidly repeated gradient and radio frequency (RF) pulses to achieve continuous labeling with high efficiency is characterized. The theoretical underpinnings, numerical simulations, and in vivo implementation of this pulsed continuous ASL (PCASL) method are described. In vivo PCASL labeling efficiency of 96% relative to continuous labeling with comparable labeling parameters far exceeded the 33% duty cycle of the PCASL RF pulses. Imaging at 3T with body coil transmission was readily achieved. This technique should help to realize the benefits of continuous labeling in clinical imagers.
authors.affiliation: Department of Radiology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, USA.
authors.forename: Weiying
authors.initials: W
authors.lastname: Dai
authors.forename: Dairon
authors.initials: D
authors.lastname: Garcia
authors.forename: Cedric
authors.initials: C
authors.lastname: de Bazelaire
authors.forename: David C
authors.initials: DC
authors.lastname: Alsop
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000098:blood supply / Q000502:physiology*; D002536:Cerebral Arteries / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011846:Radio Waves; D015203:Reproducibility of Results; D012212:Rheology / Q000379:methods*; D012680:Sensitivity and Specificity; D013113:Spin Labels; D055815:Young Adult
chemical_list: D013113:Spin Labels