E104 Time-Resolved Three-Dimensional Phase-Contrast MRI による脳動脈瘤内血流可視化

The purpose of our study was to visualize hemodynamics in a silicon vascular model with a middle cerebral aneurysm using Time-Resolved Three-Dimensional Phase-Contrast MR Imaging (4D-Flow). We created a realistic silicon model of a right middle cerebral artery bifurcation aneurysm. We ran an aqueous solution of glycerol as a flowing fluid through the silicon vessel model with a pulsatile pump. The 4D-Flow technique is based on a radiofrequency-spoiled gradient-echo sequence and it encodes flow velocity in three orthogonal directions. This technique was carried out using 1.5T MR scanner with a voxel size of 0.88x0.88x3mm, 20 phases during one cardiac cycle, and imaging time of 48min. Time-resolved images of three-dimensional streamlines clearly demonstrated that the aneurysm had three-dimensional complex vortex flows within it during systolic phase. A helical flow at the left aspect of the aneurysm was seen along the aneurysmal wall. The point where the helical flow reversed direction was coincident with the bleb. Flow rate of the bleb was low. In our model the 4D-Flow technique provided us with time-resolved three-dimensional hemodynamic information about the intracranial aneurysm and the adjacent parent artery.