Analyses of risk factors for basilar tip aneurysms rupture using CT angiography / 中华放射学杂志

ABSTRACT

Objective:To analyze risk factors for the rupture of basilar tip aneurysms (BTA) using morphological parameters assessed on CTA.Methods:The clinical data and CTA imaging characteristics of 62 patients with BTA from March 2016 to November 2020 in Huanhu Hospital of Tianjin were analyzed retrospectively. The patients were divided into un-rupture ( n=44) and rupture ( n=18) groups according to whether the BTA ruptured. The morphological parameters of aneurysms were measured and recorded. The number, shape and orientation of aneurysms were analyzed by χ 2 test between the two groups. The length (H max), height (H p), neck width (N D), aspect ratio (AR), size ratio (SR), angle of aneurysms (AA), flow angle (FA), basilar vessel angle (BVA), the angle between the proximal long axis of bilateral posterior cerebral artery P1 segment (P1-P1 angle), the angle between the proximal long axis of bilateral superior cerebellar arteries and bifurcation angle (the sum of the angle between the basilar artery and the bilateral posterior cerebral arteries) were analyzed by independent-sample t test between the two groups. On the basis of univariate analysis, logistic regression was used to identify the independent risk factors for BTA rupture. ROC curve analysis was further performed. Results:BTA with irregular shape was more likely to break (χ 2=5.412, P<0.05). The H max[(4.18±2.11)mm], N D [(3.06±1.75)mm], P1-P1 angle (148°±18°) in the rupture group were smaller than those in the un-rupture group [(6.38±2.21)mm, (5.20±1.59)mm, 178°±25°], with statistically significant difference ( P<0.05). While AR (1.19±0.13), BVA (82°±11°), and bifurcation angle (212°±18°) in the rupture group were larger than those in the un-rupture group (1.05±0.18, 70°±10°, 181°±27°), with statistically significant difference ( P<0.05). The logistic regression analysis showed that the shape of aneurysms (β=4.878, OR=11.418, P=0.019), BVA (β=0.165, OR=1.177, P=0.043), and P1-P1 angle (β=-0.223, OR=1.080, P=0.029) were independent risk factors for BTA rupture. The ROC curve analysis showed that the cut-off value of BVA and P1-P1 angle to predict the BTA rupture were 76.7° and 158.5°, and area under curve (AUC) were 0.79 and 0.86, respectively. The AUC of combined BVA with P1-P1 angle was 0.89. Conclusion:The shape of aneurysms, BVA and P1-P1 angle are independent risk factors for BTA rupture. BTA are prone to rupture when the shape of aneurysm is irregular, BVA>76.7 ° and P1-P1 angle<158.5 °.