Comparison of visual and semiquantitative analysis of 18F-FDOPA-PET/ CT for recurrence detection in glioblastoma patients

Background. Amino acid transport imaging with 18F-FDOPA PET is increasingly used for detection of glioblastoma recurrence. However, a standardized image interpretation for 18F-FDOPA brain PET studies has not yet been established. This study compares visual and semi-quantitative analysis parameters for detection of tumor recurrence and correlates them with progression-free survival (PFS). Methods.One-hundred ten patients (72 male:38 female) with suspected tumor recurrence who underwent 18F-FDOPA PET imaging were studied. PETscans were analyzed visually (5-point scale) and semiquantitatively (lesion-to-striatum- and lesion- to-normal-brain-tissue ratios using both SUVmean and SUVmax). Accuracies for recurrence detection were calculated using histopathology and clinical follow-up for validation. Receiving operator characteristic and Kaplan-Meier survival analysis were performed to derive imaging-based prediction of PFS and overall survival (OS). Results.Accuracies for detection of glioblastoma recurrence were similar for visual (82%) and semiquantitative (range, 77%–82%) ana-lysis. Both visual and semiquantitative indices were significant predictors of PFS, with mean lesion-to normal brain tissue ratios providing the best discriminator (mean survival, 39.4 vs 9.3 months; P,.001). None of the investigated parameters was predictive for OS. Conclusions. Both visual and semiquantitative indices detected glioblastoma recurrence with high accuracy and were predictive for PFS