Comparison of 18F-FDG PET/CT imaging with different dual time 18F-FDG PET/CT with forced diuresis in clinical diagnosis of prostate cancer

The aim of this study was to compare the capability of different dual time (interval 1, 2, 3, or 4 hours) 18F-fluorodeoxyglucose (F-18-FDG) positron emission tomography/computed tomography (PET/CT) with forced diuresis to diagnose prostate cancer (PCa). A retrospective review of 273 male patients from March 2009 to June 2019, with any focal F-18-FDG uptake in the prostate gland during PET/CT imaging. Early PET/CT imaging was performed 60 minutes after FDG injection. Delayed imaging was performed 1 to 4 hours after diuretic injection. For prostate lesions with increased F-18-FDG uptake, a spheroid-shaped volume of interest was drawn, including the entire lesion, and the maximum standard uptake value (SUVmax) of the lesion was measured. The SUVmax > 2.5 after delayed imaging and the retention index > 15% were used as the diagnostic criteria for PET/CT in the diagnosis of PCa. Otherwise, it was diagnosed as the benign prostate disease. The final diagnosis was based on histological examination, associated imaging studies, or/and clinical follow-up. The results of inter-group comparison showed that the SUVmax of 1-, 2-, 3-, and 4-hour delayed imaging after diuresis in PCa group was significantly higher than that in control group (P < .05), but there was no statistical difference in SUVmax of early imaging between PCa and control group (P > .05). And the retention index of PCa group that delayed 1, 2, 3, and 4 hours after diuresis were significantly higher than those of control group, respectively (P < .05). The diagnostic sensitivity of imaging delayed 1, 2, 3, and 4 hours after diuresis was 68.8%, 81.2%, 85.7 %, and 71.4%, the specificity was 52.5%, 74.5%, 70.6%, and 65.0%, and the accuracy was respectively 58.2%, 77.4%, 76.4%, and 67.6%, the positive predictive values were 44.0%, 68.9%, 64.3%, and 58.8%, and the negative predictive value were 75.6%, 85.4%, 88.9%, and 76.5%, respectively. F-18-FDG PET/CT imaging as an imaging tool lacks certain specificity in the diagnosis of PCa, regardless of whether the imaging is delayed. The main advantage of delayed diuretic imaging in PCa is that it can significantly improve the sensitivity, especially the diagnostic effect delayed 2 hours after diuresis is better.