Morphological Distinguish of Rupture Status between Sidewall and Bifurcation Cerebral Aneurysms Caracterización Morfológica del Estado de Ruptura entre Aneurismas Cerebrales en Paredes Laterales y Bifurcaciones

We suspect that morphological change of two types of aneurysms in ruptured and unruptured aneurysms are distinguishing because of different location and haemodynamics. So it is necessary to discuss sidewall and bifurcation type aneurysms in ruptured and unruptured state respectively. We used 209 consecutive aneurysms (144 ruptured, 65 bifurcation type) to assess the following parameters in 3D: maximum diameter (Dmax), maximum height (Hmax), aspect ratio (AR), size ratio (SR), height/width ratio (HW), bottleneck factor (BNF, width/neck) and inflow angle (IR). These aneurysms were divided into four groups by whether ruptured and sidewall or bifurcation. 4 groups were pairwise compared by univariate analysis and some parameters with significant variation were analyzed by multinomial logistic. Hmax (P=0.014) and HW (P=0.001) were different significantly between ruptured bifurcation and sidewall by multinomial logistic. There was no difference between unruptured bifurcation and sidewall (P>0.05) except for SR (P=0.002) by multinomial logistic. All data of ruptured aneurysms are different significantly from unruptured aneurysms (P<0.05) except for sidewall HW (P=0.414) by univariate analysis. But only SR (P < 0.001) and IR (P=0.006) of sidewall and SR (P=0.011) and HW (P=0.001) of bifurcation was significantly different by multinomial logistic. Volume of sidewall aneurysms are larger than bifurcation aneurysms and stretch characteristic of bifurcation is more obvious in ruptured aneurysms. Flow angle is the important criteria to predict fracture not in bifurcation aneurysms but in sidewall aneurysms. Size ratio is always a very important parameter to predict rupture of aneurysm no matter in bifurcation and sidewall type.