Dynamic B0 field shimming for improving pseudo-continuous arterial spin labeling at 7 Tesla

Motivation: Increased B0 inhomogeneity along the length of brain-feeding arteries at 7 Tesla is one major issue for pseudo-continuous arterial spin labeling (PCASL), which reduces the labeling efficiency, leading to loss of perfusion signal. Goal(s): Our goal is to improve PCASL at 7 Tesla by specifically improving B0 field homogeneity of the vessels within the inversion region. Approach: We propose a vessel-specific dynamic B0 shimming method to optimize labeling efficiency without compromising the static shim over the imaging region. Results: Preliminary perfusion images indicate the superior performance of our proposed 3D dynamic shimming method over global or 2D-based correction methods. Impact: Our proposed dynamic B0 shimming method demonstrates strong potential in improving the robustness and effectiveness of PCASL, allowing the high sensitivity and spatial resolution of 7T ASL to be fully utilized.