Diffusion-weighted MRI, 11C-choline PET/CT, and 18F-FDG PET/CT for predicting the Gleason score in prostate cancer.

Abstract

To evaluate diffusion-weighted magnetic resonance imaging (DWI), 11C-choline positron emission tomography (PET), and fluorine-18-fluorodeoxyglucose (18F-FDG) PET for predicting Gleason score in prostate cancer patients. The study cohort included 11 patients with biopsy-proven prostate cancer who underwent DWI, 11C-choline PET, and 18F-FDG PET examinations before treatment. The correlations of Gleason score with those findings were determined using Spearman's test. Multi-technique imaging performance for separating higher Gleason score (≥8) cases was also examined. Both diffusion coefficient (ADC) map and 11C-choline PET/computed tomography (CT) findings showed prostate cancer in all 11 patients, while 18F-FDG PET/CT was only successful in 6 (54.5%) cases, thus no further evaluations of that modality were performed. A moderately negative correlation was observed between Gleason score and ADC value for the primary tumor shown by DWI, though the difference was not significant (r=-0.49, P=0.13). In contrast, a strongly significant positive correlation was observed between Gleason score and maximum standardized uptake value (SUVmax) for the primary tumor in 11C-choline PET findings (r=0.85, P=0.0010). Sensitivity, specificity, and accuracy for separating higher (≥8) from lower (≤7) Gleason score were 87.5%, 33.3%, and 72.7%, respectively, with a best cut-off value of 0.78 for ADC map, and 87.5%, 100%, and 90.9%, respectively, with a best cut-off value of 6.0 for 11C-choline PET. Carbon-11-choline PET was found have a greater correlation with Gleason score than DWI and is considered to be more useful to predict a higher score in patients with prostate cancer. Fluorine-18-FDG PET was limited because of low sensitivity.