Computational fluid dynamics analysis of blood blister aneurysms: A comparative study with normal supraclinoid...

The purpose of this study was to evaluate hemodynamic differences between blood blister aneurysms (BBAs) and normal supraclinoid internal carotid arteries (ICAs) using patient-specific vascular models.

Thirteen models of ruptured BBA and 13 models of normal ICA were constructed from the petrous ICA proximally to M1 and A1 segments distally via 3D rotational angiography or MR angiography. Computational fluid dynamics (CFD) simulation was employed to calculate hemodynamic parameters, including time-average wall shear stress (TAWSS), wall shear stress gradient (WSSG), pressure difference (PD), oscillatory shear index (OSI), and relative residence time (RRT). Mann-Whitney U Test was used to identify differences between BBA and normal ICAs RESULTS: Compared with normal ICAs, BBAs exhibited significantly higher OSI (average and maximum: 0.0097/ 0.22 vs 0.0035/ 0.0135, p < 0.01), higher RRT (average and maximum: 0.60/ 8.50 vs 0.28/ 0.54, p = 0.018 & < 0.01), higher maximum WSSG (20,492 vs 9208, p = 0.012), higher maximum PD (1.34 vs 0.89, p = 0.027) and lower minimum TAWSS (0.35,Pa vs 2.55,Pa, P < 0.01). A swirling TAWSS pattern was identified in three of the four BBAs with early rebleeding post-treatment and in the two cases with in-hospital mortality.

BBAs demonstrated low and multi-directional wall shear stress on the aneurysmal wall with higher OSI and RRT compared to normal ICAs. A swirling pattern in the TAWSS map was identified as a poor prognostic factor. The findings support CFD as a promising tool for assessing rupture risk and guiding clinical decisions of BBAs.