Abstract WP223: Chronic Atherosclerotic Moyamoya Syndrome of the Middle Cerebral Artery: A Hemodynamic Study with CT Perfusion

Abstract

Background: Moyamoya vessels, an abnormal vascular collateral network at the base of the brain, are associated with moyamoya disease and secondary moyamoya syndrome. Several studies have suggested that ischemic symptoms in patients with moyamoya vessels are most closely related to hemodynamic impairment. However, few studies have evaluated cerebral perfusion state in secondary atherosclerotic moyamoya syndrome. The purpose of our study was to evaluate cerebral hemodynamics measured by acetazolamide CT perfusion (CTP) imaging in patients with moyamoya syndrome associated with symptomatic atherosclerotic occlusion of the unilateral middle cerebral artery (MCA). Methods: Multidetector helical CTP imaging was performed in 14 patients (mean age, 54.4 years), who were clinically diagnosed to have moyamoya syndrome associated with unilateral atherosclerotic steno-occlusion of the proximal MCA. All patient underwent cerebral angiography and CTP imaging. Hemodynamic quantitative parameters of regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), and mean transit time (rMTT) were measured in the anterior cerebral artery (ACA), MCA, and posterior cerebral artery (PCA) territories of both hemispheres separately. The Cerebral vascular reserve (CVR) capacity was measured using acetazolamide. Results: Mean resting rCBF in the ipsilesional ACA and MCA territories were significantly lower than in the contralateral territories (P<0.05). After acetazolamide infusion, the rCBF was significantly increased in the ipsilesional ACA, PCA, and all three contralateral territories (P<0.05) and rCBV was significantly increased in the all ipsilesional and contralateral territories (P<0.05). The CVR capacity changes were not significantly different between ipsilesional and contralateral territories. Conclusions: These findings suggest that the affected MCA territory has decreased perfusion with poor vasomotor reactivity despite abundant collateral circulation through the basal moyamoya vessels in patients with atherosclerotic moyamoya syndrome.