Abstract #4423

Improve conspicuity of distal small vessels in velocity-selective ASL MRA using variable flip angle readout

Lixin Liu¹, Lili Wang¹, Ying Hua Chu², Wenjin Liu³, Hao Li^1,4, Zhensen Chen^1,4, and He Wang^1,4,5

¹Institute of Science and Technology for Brain-inspired Intelligence, Fudan University, Shanghai, China, ²MR Research Collaboration Team, Siemens Healthineers Ltd., Shanghai, China, ³Yangzhou Institute of Precision Medicine for Kidney Diseases, Yangzhou, China, ⁴Key Laboratory of Computational Neuroscience and Brain-Inspired Intelligence (Fudan University), Ministry of Education, Shanghai, China, ⁵Human Phenome Institute, Fudan University, Shanghai, China

Synopsis

Keywords: Data Acquisition, Vessels

Motivation: The conventional velocity-selective ASL-based (VSASL) MRA's acquisition efficiency is low since a long waiting time is used for blood refreshing. A large turbo factor for acquisition window can be used, but will lead to image blurring and degraded depiction of small vessels.

Goal(s): To explore the potential of variable flip angle (VFA) strategy for improving conspicuity of distal small vessels in VSASL MRA.

Approach: Four VFA strategies were designed and compared with constant FA in vessel visualization. Vessel sharpness of ACA, MCA and PCA was calculated.

Results: Compared to constant FA, VFA has higher sharpness and can reduce the blurring of small vessels.

Impact: The sharpness was higher for VFA than constant FA, suggesting the effectiveness of the VFA strategy in reducing blurring and improving the conspicuity of distal small vessels for VSASL MRA.

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