Spatial coefficient of variation applied to arterial spin labeling MRI may contribute to predict surgical revascularization outcomes in pediatric moyamoya vasculopathy

In moyamoya vasculopathy, prolonged arterial transit time may increase the arterial spin labeling (ASL) signal heterogeneity, which can be quantitatively expressed by the spatial coefficient of variation of ASL-CBF (ASL-sCoV). The aim was to compare the accuracy of ASL-sCoV and ASL-CBF with dynamic susceptibility contrast (DSC)-CBF and time-to-peak (DSC-TTP) in the evaluation of perfusion changes and clinical outcome after encephalo-duro-arterio-myo-synangiosis (EDAMS) in pediatric moyamoya patients. A total of 37 children with moyamoya vasculopathy (mean age 6.31 years (1.12–15.42)) underwent ASL and DSC perfusion imaging at 3T before and up to 24 months after EDAMS. Mean DSC-CBF, mean DSC-TTP, mean ASL-CBF, and ASL-sCoV were calculated in middle cerebral artery territories. Generalized linear model analyses were used to evaluate temporal variations of postoperative perfusion changes and to compare these variations between patients developing valid pial collateralization and those without angiographic improvement. Relationship between perfusion parameters and clinical outcome after surgery was tested using multivariate regression analysis. Significant reduction was observed after EDAMS for ASL-sCoV (P = .002; eta-squared (η${}^2$) = 0.247) and DSC-TTP (P < .001; η${}^2$ = 0.415), whereas only a trend of increase was observed for DSC-CBF and ASL-CBF, with larger discrepancy before and 6 months after surgery. At last follow-up, children developing pial collateralization showed lower absolute ASL-sCoV (P = .002 Cohen's d = 0.84) and DSC-TTP (P = .027; Cohen's d = 0.64) and higher DSC-CBF (P = .002; Cohen's d = − 0.55) compared with those without vascular improvement. Low preoperative and early post-surgical ASL-sCoV predicted better long-term neurological outcome (P < .001; ß = − 0.631). ASL-sCoV may contribute to predict surgical outcomes in pediatric moyamoya patients undergoing EDAMS.