Ruptured middle cerebral artery bifurcation aneurysms with concomitant intracerebral hematoma: Clinical and morphological risk factors

The prognosis for intracerebral hematoma (ICH) following the rupture of a middle cerebral artery bifurcation (Mbif) aneurysm is poor. We compared patients with isolated diffuse subarachnoid hemorrhage (SAH) (without ICH) following Mbif aneurysm rupture to those with both SAH and ICH to evaluate clinical and morphological risk factors for ICH. A retrospective study was conducted on 112 patients with ruptured Mbif aneurysms treated between July 2016 and December 2021. We investigated age, sex, medical history (hypertension, diabetes mellitus, and smoking), rebleeding, aneurysm neck and dome size, bottleneck factor, aspect ratio, dome projection, trunk diameters and ratios, parent artery (M1) dimensions, angles between both trunks (γ1, γ2, γ3), as well as M1 length and diameter, and internal carotid artery/M1 (α) and internal carotid artery/anterior cerebral artery (β) angles. These measurements were obtained using computerized tomography angiography to assess risk factors. A total of 88 patients (78.6%) with ruptured Mbif aneurysms who met the inclusion criteria were included in the study. A total of 39 (44.3%) patients had SAH with ICH, while 49 (53.7%) patients had pure diffuse SAH. Rebleeding was significantly higher in patients with ICH (P = .02). Morphological analysis revealed that the decrease in M1 diameter and α angle, along with an increase in aneurysm size and neck, were significantly different in the ICH group (P = .025, P = .012, P = .009, and P = .005, respectively). Receiver operating characteristic curve analysis showed that a cutoff value of α = 125° had the highest diagnostic accuracy (area under the curve = 0.71), with a sensitivity of 86.26% and specificity of 68.7%. The formation of ICH following the rupture of Mbif aneurysms is associated with specific morphological parameters.