F-18 FDG PET/CT after diuretic for the patients with bladder cancer: Correlation of SUV on PET with ADC on MRI

1673 Objectives By using diuretics after administration of FDG, bladder activity is significantly decreased and low enough for evaluation of glucose metabolism in bladder lesions. The purpose of the study was to determine the correlations between FDG uptake acquired after diuretic on PET/CT and diffusion weighted MR imaging (DWI) for the patients with bladder cancer. Methods Forty-five consecutive patients with known bladder cancer underwent diuretic PET/CT and MRI. After whole-body PET/CT scan, 0.2mg/ kg body-weight of furosemide was administrated 120 minutes after FDG injection. Delayed PET/CT was performed after an uptake phase of 180 min, followed by a contrast-enhanced CT. All the patients underwent MRI including diffusion-weighted images (b = 1000 sec/mm2) within three days. Maximal SUV (SUVmax), average SUV (SUVmean), minimum apparent diffusion coefficient (ADCmin) and average ADC (ADCmean) of each lesion were measured by placing a region of interest on FDG PET/CT and MRI, respectively. To determine the correlation between glucose metabolism and tumor cellularity in the bladder cancers, the SUVmax and SUVmean on PET were statistically compared with the ADCmin and ADCmean on MRI by the Spearman9s rank test. Results 50 bladder cancers in 45 patients were histo-pathologically confirmed as urothelial carcinomas and were statistically compared between PET/CT and MRI. The mean and standard deviation of SUVmax and SUVmean was 27.1 ± 28.1 and 8.1 ± 4.9, respectively; ADCmin and ADCmean was 0.76 ± 0.17 × 10-3 mm2/sec and 1.27 ± 0.22 × 10-3mm2/sec, respectively. There was significant inverse correlation between SUVmax and ADCmin (r=-0.82, p Conclusions By use of diuretics, FDG uptakes of bladder cancers can be evaluated and compared with ADC values on MRI. SUVmax on diuretic PET statistically correlates with ADCmin on MRI, suggesting the association between glucose metabolism and tumor cellularity in bladder urothelial cancers.