Purpose: To present a constrained slice-dependent (CSD) background-suppression (BS) scheme in 2D arterial spin labeling (ASL) using simultaneous multislice acquisition with blipped-CAIPIRINHA (controlled aliasing in parallel imaging results in higher acceleration). Methods: Background suppression for 2D acquisition is challenging because of the multiple nulling points required for sequential slice readout. Constrained slice-dependent BS exploits the simultaneous multislice technique to reduce the readout duration, and uses slice-dependent premodulation pulses to achieve BS across slice groups. The proposed scheme was evaluated by in vivo brain experiments at 3 Tesla with multiband acceleration factors up to four. The utility of CSD BS was demonstrated through comparison against standard 2D acquisitions as well as 3D-BS pseudo-continuous ASL (pCASL). Results: An average of 95% background signal reduction was achieved with CSD BS. As a result, the temporal signal-to-noise ratio (SNR) increased 48.2/39.9/36.9/36.0% and spatial SNR increased 132.5/80.0/63.5/54.2 in CSD-BS MB-1/2/3/4 scans, respectively. Whole-brain coverage was achievable with CSD-BS pCASL with MB-4, which yielded comparable spatial SNR as 3D BS pCASL. Conclusions: The proposed CSD-BS scheme for 2D-SMS pCASL offers a promising approach for effective suppression of background signals across a wide range of T1 to achieve whole-brain perfusion imaging. Magn Reson Med 79:394–400, 2018.
Bibliographical noteFunding Information:
This research was supported by the National Institute of Health (NIH) Grants UH2-NS100614, R01-EB014922, and P41-EB015894. Received 20 September 2016; revised 20 January 2017; accepted 24 January 2017 DOI 10.1002/mrm.26643 Published online 15 February 2017 in Wiley Online Library (wileyonlinelibrary. com).
- arterial spin labeling (ASL)
- background suppression (BS)
- controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA)
- simultaneous multislice (SMS)