Quantitative analysis of early postoperative cerebral blood flow contributes to the prediction and diagnosis of cerebral hyperperfusion syndrome after revascularization surgery for moyamoya disease

Objective: Cerebral hyperperfusion syndrome (HPS) is a potential complication of extracranial-intracranial (EC-IC) bypass for moyamoya disease; however, the pathological threshold of the early cerebral blood flow (CBF) increases after EC-IC bypass has yet to be determined. The purpose of this study is to evaluate the predictive and diagnostic values of early quantitative CBF analysis for the detection of HPS after EC-IC bypass for moyamoya disease. Methods: We quantitatively evaluated regional CBF at the site of the anastomosis in 23 patients with moyamoya disease aged between 18 and 66 years (mean, 39.6) before and 1 day after superficial temporal artery-middle cerebral artery anastomosis by an auto-radiographic method using N-isopropyl-p-[I-123] iodoamphetamine single-photon emission computed tomography. Results: Regional CBF 1 day after surgery was significantly higher in patients with HPS (n = 5; mean, 54.6 ml/100 g/minutes) than in patients without HPS (n = 18; mean, 40.5 ml/100 g/minutes) (P = 0.038). The postoperative/preoperative CBF ratio was significantly higher in patients with HPS (1.84) than in patients without HPS (1.34) (P = 0.044). Multivariate analyses showed that the regional CBF value 1 day after surgery (P = 0.036) and operating on the left hemisphere (P = 0.026) significantly correlated with HPS. All patients with HPS developed symptoms and/or intracerebral hemorrhage more than 2 days after EC-IC bypass. Receiver operating characteristic analysis indicated that the cutoff value of pathological postoperative CBF increase was 46.1 ml/100 g/minutes (sensitivity = 80%, specificity = 77.8%, AUC value = 0.81). Conclusion: Quantitative analysis of early postoperative CBF is useful for predicting and diagnosing HPS after revascularization surgery for moyamoya disease.