巨大脳動脈瘤の流体力学的特徴

抄録

We performed a retrospective study to estimate the relationship between aneurysmal thrombosis and geometrical characteristics in giant aneurysms. We used aspect ratio (aneurysm depth/neck) and area ratio (ratio of the cross-sectional area of bifurcated arteries) to evaluate the geometrical characteristics. We analyzed 25 cases with giant saccular aneurysms that underwent precise neuroradiological examinations in our institute over a recent 10-year period. Twelve aneurysms developed at the ICA cavernous portion. These aneurysms were classified as non-branching aneurysms and showed a mean aspect ratio of 5.2. Nine aneurysms classified as bifurcation aneurysms developed at the MCA bifurcation (5 cases) and at the basilar bifurcation (4 cases). All of these aneurysms were buried in the brain tissue. The mean aspect ratios were 8.2 and 5.1, respectively, and the mean area ratios were 2.6 and 1.2, respectively. In the non-branching aneurysms, blood flow was shown along the aneurysmal wall, and intra-aneurysmal thrombuses were shown in the center of the aneurysms. In the bifurcation aneurysms, blood flow was demonstrated around the neck, and intra-aneurysmal thrombus was shown in the dome side. The area of thrombus was positively associated with stagnant areas of blood flow. We discuss the mechanism of intraaneurysmal clotting.