Jianping Song1, Fengping Zhu1,2, Yi Qian2, Chubin Ou3, Jiajun Cai1, Xiang Zou1, Zehan Wu1, Wei Zhu1, Liang Chen1, Ying Mao1. 1. Department of Neurosurgery, Huashan Hospital, Fudan University, Shanghai, China. 2. Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, Australia. 3. Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology, Hong Kong, China.
Abstract
BACKGROUND: The morphological and hemodynamic features differ between middle cerebral artery (MCA) bifurcations with and without aneurysms. OBJECTIVE: To investigate the morphological and hemodynamic differences between aneurysmal MCA bifurcation and contralateral nonaneurysmal anatomy. METHODS: Computed tomography angiography of 36 patients with unilateral small saccular MCA bifurcation aneurysms was evaluated. The parent-daughter angles (φ1 for larger branch and φ2 for smaller branch), bifurcation angle (φ = φ1 + φ2), inclination angle (γ angle), and their relationships with the MCA bifurcation locations were analyzed. Computational fluid dynamics simulation was performed in 6 cases to explore the hemodynamics influenced by the bifurcation morphology. RESULTS: The φ angle was significantly higher in aneurysmal than contralateral nonaneurysmal bifurcations (160.8° ± 31.0° vs 99.0° ± 19.2°, respectively; P = .000); the φ1, φ2, and γ angles were also higher. However, by regression analysis combined with MCA bifurcation locations, only the φ angle might be associated with the aneurysm presence (odds ratio = 1.120, 95% confidence interval = 1.059-1.185) and a φ angle cut-off of 124.8° was established. Computational fluid dynamics simulation demonstrated that flow resistance of the wider aneurysmal MCA bifurcation was significantly higher than that on the contralateral side. CONCLUSION: A larger φ angle was more prevalent in aneurysmal than nonaneurysmal MCA bifurcations, and the higher flow resistance caused by the larger φ angle might be a potential hemodynamic factor associated with MCA aneurysm presence.
BACKGROUND: The morphological and hemodynamic features differ between middle cerebral artery (MCA) bifurcations with and without aneurysms. OBJECTIVE: To investigate the morphological and hemodynamic differences between aneurysmal MCA bifurcation and contralateral nonaneurysmal anatomy. METHODS: Computed tomography angiography of 36 patients with unilateral small saccular MCA bifurcation aneurysms was evaluated. The parent-daughter angles (φ1 for larger branch and φ2 for smaller branch), bifurcation angle (φ = φ1 + φ2), inclination angle (γ angle), and their relationships with the MCA bifurcation locations were analyzed. Computational fluid dynamics simulation was performed in 6 cases to explore the hemodynamics influenced by the bifurcation morphology. RESULTS: The φ angle was significantly higher in aneurysmal than contralateral nonaneurysmal bifurcations (160.8° ± 31.0° vs 99.0° ± 19.2°, respectively; P = .000); the φ1, φ2, and γ angles were also higher. However, by regression analysis combined with MCA bifurcation locations, only the φ angle might be associated with the aneurysm presence (odds ratio = 1.120, 95% confidence interval = 1.059-1.185) and a φ angle cut-off of 124.8° was established. Computational fluid dynamics simulation demonstrated that flow resistance of the wider aneurysmal MCA bifurcation was significantly higher than that on the contralateral side. CONCLUSION: A larger φ angle was more prevalent in aneurysmal than nonaneurysmal MCA bifurcations, and the higher flow resistance caused by the larger φ angle might be a potential hemodynamic factor associated with MCA aneurysm presence.