We analyzed cortical microvascular parameters using intraoperative ICG (Indocyaninegreen)-Videoangiography in 13 patients with Moyamoya disease, and carried out correlative studies by comparing them with clinical parameters obtained by digital subtraction angiography, physical examination, and regional cerebral blood flow studies. Patients with reduced cerebrovascular reserve capacity were characterized by increased microvascular surface area (MVSA). In addition, MVSA correlated positively with arterial microvascular transit time. Asymptomatic patients were characterized by increased arterial microvascular transit time. We show that patients with a higher arteriogenic potential to alter cortical microvasculature are characterized by a more favorable hemodynamic situation and reduced clinical symptoms.