The cerebral metabolism, such as the oxygen extraction fraction (OEF), in remote ischemic lesions following revascularization for moyamoya disease (MMD) has not yet been fully elucidated. We herein report a patient with an increased OEF in a remote ischemic lesion after revascularization in a case of adult-onset MMD. A 21-year-old woman suffered from a left parietal lobe infarction due to MMD. At 2 months after onset, left superficial temporal artery (STA)-middle cerebral artery (MCA) bypass and encephalo-myo-synangiosis (EMS) were performed. The postoperative course was uneventful. 15O-positron emission tomography (PET) performed at 2 months after the first operation revealed an increased OEF in the contralateral (right) frontal lobe that was suspected of being possible remote ischemia. The patient underwent right STA-MCA bypass and EMS. 15O-PET at 14 days after the second operation revealed an increased OEF in the contralateral (left) occipital lobe that was suspected of potentially being remote ischemia caused by a watershed shift. Two years after the second surgery, left occipital artery (OA)-posterior cerebral artery (PCA) anastomosis and EMS were performed due to transient right hemianopsia. Neither rebleeding nor ischemic complications occurred 2 years after the third surgery. We need to be alert for the possible progression of PCA stenosis in MMD after revascularization. It might induce remote ischemia after revascularization. OA-PCA bypass is therefore considered to be an effective treatment option in such cases.
Keywords: moyamoya disease; oxygen extraction fraction; remote ischemia; watershed shift.
© The Author(s) 2021.