Effects of surgical revascularization on cerebral oxygen metabolism in patients with Moyamoya disease: an 15O-gas positron emission tomographic study.

BACKGROUND AND PURPOSE This prospective study was aimed to evaluate the effects of surgical revascularization on cerebral oxygen metabolism in moyamoya disease. METHODS This study included totally 69 hemispheres of 42 patients who underwent superficial temporal artery to middle cerebral artery anastomosis and indirect bypass for moyamoya disease between 2000 and 2011. There were 12 children and 30 adults. MRI and (15)O-gas positron emission tomography were performed before and 3 to 4 months after surgery. Hemodynamic and metabolic parameters were precisely quantified and statistically analyzed. RESULTS Preoperative positron emission tomographic scans revealed that cerebral blood flow was decreased, cerebral blood volume was increased, and cerebral metabolic rate for oxygen was decreased in both pediatric and adult patients. Cerebral metabolic rate for oxygen reduction was observed in ≈80% of pediatric (16/21; 76%) and adult hemispheres (38/48; 79%). Surgical revascularization resolved hemodynamic compromise in all operated hemispheres. Cerebral metabolic rate for oxygen significantly improved in pediatric patients without parenchymal lesions (n=8), but not those with parenchymal lesions (n=8). Multivariate analysis revealed that cerebral metabolic rate for oxygen significantly improved in younger adult patients without parenchymal lesions (P=0.0264; odds ratio, 0.88; 95% confidence interval, 0.79-0.99). CONCLUSIONS Cerebral oxygen metabolism is significantly depressed in ≈80% of the involved hemispheres of moyamoya disease and improves in pediatric and younger adult patients without parenchymal lesions after bypass surgery. Cerebral oxygen metabolism may be reversibly depressed in response to cerebral ischemia in them although the underlying mechanisms are still unclear.