Prediction of postoperative neovascularization after indirect bypass in adult moyamoya disease: a preoperative clinical and perfusion-based model.

Abstract

The aim of this study was to identify preoperative clinical, angiographic, and quantitative perfusion predictors of postoperative neovascularization (PNV) after indirect bypass (IB) in adult moyamoya disease (MMD). The authors retrospectively reviewed 128 hemispheres in 106 adults with MMD who underwent IB at a single institution between January 2018 and December 2024. Preoperative time-to-maximum (Tmax) volumes were obtained from CT perfusion analysis using thresholds of > 4 seconds and > 6 seconds. PNV was evaluated 6 months after surgery using the Matsushima grading system. Multivariable logistic regression analyses were performed to identify independent predictors of favorable PNV in two models, defined as Matsushima grade (MG) A and as MG A or B, respectively. Receiver operating characteristic curve analysis was used to determine optimal cutoff values. At 6 months postoperatively, 38.3% of hemispheres achieved MG A PNV, and 67.2% achieved MG A or B PNV. For MG A PNV, younger age (OR 0.95, 95% CI 0.91-0.99; p = 0.009) and larger preoperative volume of Tmax > 6 seconds (OR 1.022, 95% CI 1.01-1.03; p < 0.001) were significant predictors, with an optimal cutoff value of 33.5 mL for Tmax > 6 seconds (area under the curve [AUC] 0.805, sensitivity 76%, specificity 75%). For MG A or B PNV, transient ischemic attack at presentation (OR 2.90, 95% CI 1.12-7.97; p = 0.033) and larger preoperative volume of Tmax > 4 seconds (OR 1.019, 95% CI 1.01-1.03; p < 0.001) were identified as significant predictors, with an optimal cutoff value of 111.5 mL for Tmax > 4 seconds (AUC 0.817, sensitivity 70%, specificity 93%). In adult MMD, greater preoperative ischemic burden measured by volumes of tissue with Tmax delays > 4 seconds or > 6 seconds predicted favorable PNV after IB. Younger age and transient ischemic attack at presentation were also associated with better PNV. This study highlights the role of perfusion parameters, together with clinical factors, in surgical decision-making and individualized treatment planning.