We report a patient with an unruptured, large arteriovenous malformation that was treated by staged, superselective embolization with liquid agents and by an investigation of the hemodynamic changes accompanying embolization. A 29-year-old man presented with headache and left upper quadrantanopsia. A neuroradiological study revealed a large right temporo-occipital arteriovenous malformation, and angiography disclosed poor filling of the adjacent vessels. In the venous phase, marked cortical reflux, suggesting venous hypertension, was also observed. Single photon emission computed tomography scanning with N-isopropyl-p-iodine-123- iodoamphetamine disclosed a low-perfusion area in the ipsilateral occipital and temporal lobes. After embolization, cerebral blood flow and the clinical symptoms attributed to ischemia improved. A follow-up study 1 year later demonstrated that the patient's improvement was stable. Single photon emission computed tomography confirmed that embolization achieves an improved cerebral blood flow.