Differentiating low- and high-grade pediatric brain tumors using a continuous-time random-walk diffusion model at high b -values

Purpose To demonstrate that a continuous-time random-walk (CTRW) diffusion model can improve diagnostic accuracy of differentiating low- and high-grade pediatric brain tumors. Methods Fifty-four children with histopathologically confirmed brain tumors underwent diffusion MRI scans at 3Twith 12 b-values (0-4000 s/mm2). The diffusion imageswere fit to a simplified CTRW model to extract anomalous diffusion coefficient, Dm, and temporal and spatial heterogeneity parameters, α and β, respectively. Using histopathology results as reference, a k-means clustering algorithm and a receiver operating characteristic (ROC) analysis were employed to determine the sensitivity, specificity, and diagnostic accuracy of the CTRW parameters in differentiating tumor grades. Results Significant differences between the low- and high-grade tumors were observed in the CTRW parameters (p-values