Motivation: While interest in multi-delay pseudo-continuous arterial spin labelling (MD-pCASL) is growing, the clinical need for efficient acquisition and visualisation of both short and longer delay times has not been technically established. Goal(s): The goal is to validate short (500 ms) to long (5000 ms) delay combined compact approach MD-pCASL schemes in terms of SNR and quantification. Approach: Three schemes, sequential variable-TR (vTR, 2min 57sec), single-control fixed-TR (fixTR, 2min 25sec) and a hybrid of vTR and time-encoded (Hybrid, 2min 51sec) were implemented and compared on SNR and quantitative values. Results: Highest SNR and reasonable quantitative values were obtained by Hybrid scheme. Impact: Hybrid MD-ASL was shown to cover short to long delays and demonstrated superior in terms of higher SNR, measuring reasonable quantitative parameters, and scan time. Use of the scheme in neurovascular and neuro-oncology applications is expected to be advantageous.
Obara et al. (Tue,) studied this question.