Malignant Supratentorial Astrocytoma Treated with Postoperative Radiation Therapy: Prognostic Value of Pretreatment Quantitative Diffusion-weighted MR Imaging

Purpose: To retrospectively evaluate whether the minimum apparent diffusion coefficient (ADC) of the tumor seen on pretreatment magnetic resonance (MR) images is of prognostic value in patients with malignant supratentorial astrocytoma. Materials and Methods: The study was approved by the institutional review board; the requirement for informed patient consent was waived. Between June 1996 and November 2003, 79 patients (44 male, 35 female; age range, 16–76 years) with malignant supratentorial astrocytoma underwent pretreatment MR imaging. Patient age, symptom duration, neurologic function, mental status, Karnofsky performance scale (KPS) score, extent of surgery, histopathologic diagnosis, tumor component enhancement, and minimum ADC were assessed at factor analysis of survival. Radiation Therapy Oncology Group–recursive partitioning analysis (RTOG-RPA) criteria were used to validate the prognostic value of the minimum ADC. Kaplan-Meier survival curves, the log-rank test, and the multivariate Cox proport...