Gregory J. Metzger1,
Sebastian Schmitter1, Xiufeng Li1, Pierre-Francois Van
de Moortele1, Peter Schmitt2, Xiaoming Bi3
1Center
for Magnetic Resonance Reserach, University of Minnesota, Minneapolis, MN,
United States; 2MR Application & Workflow Development, Siemens
AG, Erlangen, Germany; 3Cardiovascular MR R&D, Siemens Healthcare,
Chicago, IL, United States
Arterial spin labeled (ASL) 4D MRA has been shown to be a valuable method for simultaneously assessing anatomic structure and dynamic filling of cerebral arteries. Beyond improved SNR and parallel imaging performance, performing these studies at ultrahigh will improved visualization of distal vessels, especially in conditions of reduced flow, due to prolonged T1 relaxation times resulting in more persistent labeling. A dynamically applied transmit B1 (B1+) shimming strategy was employed to accommodate limitations on peak B1+, B1+ homogeneity and SAR. Initial results showing signal persistence in distal arteries are shown.