DCE-MRI of the prostate using shutter-speed vs. Tofts model for tumor characterization and assessment of aggressiveness.

Purpose: To quantify Tofts model (TM) and shutter-speed model (SSM) perfusion parameters in prostate cancer (PCa) and noncancerous peripheral zone (PZ) and to compare the diagnostic performance of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to Prostate Imaging and Reporting and Data System(PI-RADS) classification for the assessment of PCa aggressiveness. Materials and Methods: Fifty PCa patients (mean age 60 years old) who underwent MRI at 3.0T followed by prostatectomy were included in this Institutional Review Board-approved retrospective study. DCE-MRI parameters (K-trans, v(e), k(ep) [TM& SSM] and intracellular water molecule lifetime si [SSM]) were determined in PCa and PZ. Differences in DCE-MRI parameters between PCa and PZ, and between models were assessed using Wilcoxon signed-rank tests. Receiver operating characteristic (ROC) analysis for differentiation between PCa and PZ was performed for individual and combined DCE-MRI parameters. Diagnostic performance of DCE-MRI parameters for identification of aggressive PCa (Gleason >= 8, grade group [GG] >= 3 or pathology stage pT3) was assessed using ROC analysis and compared with PI-RADSv2 scores. Results: DCE-MRI parameters were significantly different between TM and SSM and between PZ and PCa (P < 0.037). Diagnostic performances of TM and SSM for differentiation of PCa from PZ were similar (highest AUC TM: K-trans+k(ep) 0.76, SSM: tau(i)+k(ep) 0.80). PI-RADS outperformed TM and SSM DCE-MRI for identification of Gleason >= 8 lesions (AUC PI-RADS: 0.91, highest AUC DCE-MRI: K-trans+tau(i) SSM 0.61, P=0.002). The diagnostic performance of PI-RADS and DCE-MRI for identification of GG >= 3 and pT3 PCa was not significantly different (P > 0.213). Conclusion: SSM DCE-MRI did not increase the diagnostic performance of DCE-MRI for PCa characterization. PI-RADS outperformed both TM and SSM DCE-MRI for identification of aggressive cancer.