Optimization of 3D-variable refocusing flip angle RARE imaging for high-resolution volumetric black-blood angiography.

3D rapid acquisition with relaxation enhancement or turbo spin-echo sequence is promising for black-blood angiography. In this paper, we propose a new scheme of sequence parameter optimization for "flow-void enhanced" volumetric black-blood angiography. Although black-blood imaging has numerous applications, we focused on the carotid artery in this study. All experiments were performed on a 3.0-T imager. The methods used were a flow phantom study and a volunteer study. From the results, the optimal parameters for black-blood angiography were the use of very-low refocusing flip angles, use of a "90° + α/2" refocusing flip angle sweep, and "flow sensitization" at the "in-plane flow" situational imaging plane. This sequence can be used for 3D volumetric black-blood angiography and vessel wall imaging.