Whole-Brain SNR-Efficient Pseudo-Continuous Arterial Spin Labeling at 7T

Motivation: The high SAR burden of PCASL at 7T typically requires long TRs and short label durations, reducing SNR efficiency and perfusion measurement accuracy. Goal(s): Our goal was to maximize the SNR efficiency of PCASL at 7T. Approach: We optimized the PCASL B1+/gradient parameters and background suppression pulses to maximize SNR efficiency (i.e., balancing labeling efficiency and SAR), and utilized VERSE and dynamic B0 shimming to reduce SAR. Results: Compared to optimizing the PCASL parameters for maximum labeling efficiency, our max-SNR efficiency optimized parameters increased SNR efficiency by 38% and reduced TRs by 41% in vivo. Impact: The improved SNR efficiency of our optimized 7T PCASL parameters increases the advantages of ultra-high field perfusion measurements, enabling robust and high-SNR perfusion measurement in clinically viable scan times.