Comment on Hatzoglou et al: Dynamic contrast-enhanced MRI perfusion versus 18FDG PET/CT in differentiating brain tumor progression from radiation injury.

We read with great interest the paper by Hatzoglou et al, recently published in Neuro-Oncology,1 concerning the discrimination between progressive disease and radiotherapy-induced changes in brain tumors, which is a clinical challenge of paramount importance. To address this diagnostic problem, the authors compared dynamic contrast enhanced (DCE) MRI and fluorine-18-fluorodeoxyglucose (FDG) PET/CT in a total of 53 patients with primary brain tumors (n = 29) or brain metastases (n = 26). They found that the DCE MRI–derived plasma volume ratio (Vpratio) and transfer coefficient ratio (Ktransratio), as well as the FDG PET–derived standardized uptake value ratio (SUVratio) were useful in distinguishing between progression and radiation injury, both in the overall cohort and in the 2 main subgroups (primary and secondary brain tumors). They concluded, however, that DCE MRI–derived Vpratio was the “most robust” predictor of progression after showing a trend toward higher performances for Vpratio with respect to SUVratio (sensitivity and specificity = 92% and 77% vs 68% and 82%; AUC = 0.87 vs 0.75, P = .061, for Vpratio and SUVratio, respectively)