Velocity-selective continuous arterial spin labeling

Motivation: Velocity-selective arterial spin labeling (VSASL) addresses transit delay errors of conventional ASL methods, but suffers from a lower signal-to-noise ratio (SNR) than standard pseudocontinuous ASL (PCASL). Goal(s): To develop velocity-selective continuous ASL (VS-CASL) for improved SNR with the removed transit delay. Approach: A delay alternating with nutation for tailored excitation (DANTE) pulse was applied immediately after global saturation to maintain the magnetization of flowing spins at a very low level until these spins decelerate below a cutoff velocity, serving as velocity-selective continuous labeling. Results: The proposed approach of VS-CASL demonstrated a similar contrast to other ASL methods with increased SNR. Impact: This work demonstrated a novel approach to ASL perfusion imaging, combining the advantages of VSASL and PCASL, and showing the potential to eliminate transit delay and enhance SNR.