Morphological differences between ruptured and unruptured basilar bifurcation aneurysms

Abstract

Background: Aspect ratio (AP), daughter artery ratio (DA), and lateral angle ratio (LA) have been reported in middle cerebral artery bifurcation aneurysms to correlate with rupture status. Objective: To study the differences in AP, DA, LA, and aneurysm orientation between ruptured and unruptured basilar bifurcation aneurysms. Methods: Three-dimensional (3D) angiograms of patients with basilar bifurcation aneurysms were analyzed for AP, DA, and LA. Aneurysm projection was classi fied as type A if the long axis of aneurysm was along basilar artery and type-B if otherwise. Results: Thirty-one ruptured and 17 unruptured aneurysms were analyzed. The APs were significantly different (p = 0.008), 2.63 ± 1.1 for ruptured aneurysms and 1.7 ± 0.55 for unruptured aneurysms. AP ≥ 1.9 correlated with rupture status with 68% sensitivity and 70% specificity. Type-A configuration was significantly associated with ruptured aneurysms with an odds ratio (OR) of 5.9. LAs were 0.9 > 0.4 and 1.4 ± 0.8 for ruptured and unruptured aneurysms, respectively, and the difference tended to be significant (p = 0.56). DAs were 1.25 ± 0.22 and 1.21 ± 0.19 for ruptured and unruptured aneurysms without any statistical difference. Conclusion: AP > 1.9, type-A configuration, and lower LA is associated with ruptured basilar bifurcation aneurysms. DA did not differ between ruptured and unruptured aneurysms © 2013 Georg Thieme Verlog KG.