Jon-Fredrik Nielsen1, Luis Hernandez-Garcia1
1Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States
Arterial Spin Labeling (ASL) provides quantitative and reproducible measurements of cerebral blood flow, and is an attractive method for functional MRI. Most existing ASL fMRI protocols are based on 2D multislice or 3D spin-echo, and suffer from low image signal-to-noise ratio (SNR) or through-plane blurring. 3D ASL with multi-shot (segmented) readouts can improve the SNR efficiency relative to 2D multislice, and does not suffer from T2-blurring. We characterize the temporal SNR of a segmented 3D spiral ASL sequence, and investigate the effects of RF phase-cycling scheme and flip angle schedule on the ASL time-course signal. We conclude that RF-spoiled segmented 3D spiral ASL with a cubic flip angle schedule starting at 15o can produce high-quality functional activation maps with only modest through-plane blurring.