An 11-year-old boy was admitted to the hospital complaining of progressive weakness of the right arm for the past 6 days and unclear enunciation, accompanied by nausea and vomiting for the past 2 days. An MR examination raised questions as to a cerebral infarction of the left parietal and frontal lobe, which was confirmed by a CT 11 days later (Fig. 1). DSA images (Fig. 2) indicated the possibility of a Moyamoya disease. CTA and Volume Perfusion CT (VPCT) examinations were ordered for preoperative planning.