Pathogenesis of aneurysms on major vessels in moyamoya disease and management outcome

•NOVA showed significantly lower PCA flow in MMD patients with aneurysms.•75% of aneurysms in MMD patients showed enlarged posterior communicating arteries.•Robust blood flow across PCOM potentiates anterior circulation aneurysm formation. Patients with moyamoya disease develop intracranial aneurysms at a higher rate than the general population. The authors aimed to test the hypothesis for development of aneurysms on large arteries in such patients using quantitative vessel imaging. Twenty-six patients representing 3.7% of moyamoya disease patients in our database were retrospectively analyzed with respect to aneurysm characteristics, management modalities, and outcome. Quantitative arterial flow data in patients with and without aneurysms were obtained using noninvasive quantitative vessel imaging technology and microflow-probe in moyamoya. Kruskal-Wallis one-way analysis of variance was used for case-control comparison. Twelve aneurysms were managed surgically, seven using the endovascular route, and eight were observed on follow-up to the primary revascularization procedure. The mean modified Rankin score after aneurysm and disease management was 1.29 at follow-up. The mean quantitative blood flow (ml/min) in the posterior cerebral artery was 98.4 and 133.5 (p = 0.04) in moyamoya disease patients with and without aneurysms. In moyamoya disease, aneurysm development can potentially occur in the anterior circulation due to robust blood flow across communicating arteries from the posterior circulation.