Combining Machine-Measured Morphometric, Geometric, and Hemodynamic Factors to Predict the Risk of Aneurysm Rupture at the Middle Cerebral Artery Bifurcation

Abstract

Middle Cerebral Artery Bifurcation Aneurysm (MbifA) is associated with a high risk of rupture and poor overall prognosis in patients once it ruptures. Morphological, geometric, and hemodynamic parameters have been identified as factors contributing to the rupture of intracranial aneurysms. However, there are no studies that combine these 3 types of parameters to specifically target MbifA rupture. This study enrolled all patients with MbifAs diagnosed at our treatment center from 1 April 2021 to 31 July 2023 who met the study criteria. All patients underwent digital subtraction angiography examination to obtain 3D rotational angiography data. We imported the complete image data into the Aneurysm/Artery Reconstruction and Analysis machine to obtain 13 morphological parameters (Dneck, Ddome, Height, Dmax, Dartery, aspect ratio [AR], size ratio, dome-neck-ratio [DNR], height-artery-ratio, bottleneck factor, Inflow Angle, Incline Angle, Arterial Angle), 5 geometric parameters (V,S,undulation index [UI], ellipticity index [EI],nonsphericity index [NSI]), and 5 hemodynamic parameters (wall shear stress [WSS], the maximum WSS, the parent artery WSS, the normalized WSS [NWSS], oscillatory shear index [OSI]). All the above significant parameters were tested by univariate and multivariate analyses to find out the independent discriminatory factors. A total of 49 MbifAs (16 ruptured and 33 unruptured) from 44 patients were included in the study. Height (P= 0.033), AR (P= 0.007), DNR (P= 0.011), EI (P= 0.042), NSI(P= 0.030), UI(P= 0.027), WSS(P= 0.033), and NWSS(P= 0.002) were all associated with MbifA rupture in univariate analyses, but only NWSS was an independent risk factor (P= 0.036, OR=0.046, 95% CI: 0.003-0.815) in multivariate logistic regression analysis. Height, AR, DNR, EI, UI, NSI, WSS, and NWSS may be correlated with MbifA rupture, but only NWSS was an independent risk factor. A lower NWSS was associated with a higher risk of MbifA rupture. No significant differences were observed in the angle parameters, including the Inflow Angle, between ruptured and unruptured MbifAs. OSI was significantly increased at the dome of the aneurysm but the mean OSI was not found to be associated with MbifA rupture.