Effects of dynamic contrast enhancement on diffusion weighted imaging score of 3 in prostate imaging reporting and data system version 2 of peripheral zone

Abstract

Objective: To investigate the effects and value of dynamic contrast-enhanced (DCE) on diffusion-weighted imaging (DWI) score 3 in the prostate imaging data and reporting system version 2(PI-RADS V2)of peripheral zone. Methods: A retrospective study of consecutive 204 cases of prostate disease in peripheral zone was conducted from January 2015 to January 2018, including 169 cases of prostate cancer and 35 cases of non-prostate cancer. All cases were examined multi-parametric MR imaging on a 3-T MR scanner and confirmed by pathology. Images were analyzed according to PI-RADS V2.Inter-reader agreement of scores was evaluated by kappa coefficient. The constituent ratio of clinically significant prostate cancer (csPCa) in PI-RADS V2 overall scores 3, 3+1 and 4 were calculated and analyzed by non-parametric Chi-square test to determine whether the difference in composition ratio was significant. The positive rate of DCE in diffusion weighted imaging (DWI) score 3 and 4 were calculated. Results: There were 68.6%(140/204) cases in 204 patients with peripheral prostate disease who scored PI-RADS V2 overall score of 3,3+1 and 4. Kappa value was higher for the PI-RADS V2 overallscore of 4 than 3 or 3+1 in the PZ (k values of 0.802 vs 0.737 or 0.591, respectively; all P<0.01). The constituent ratio of csPCa in PI-RADS V2 overallscore of 3, 3+1 and 4 were 16.7%(3/18),43.2%(19/44),78.2%(61/78), the difference of which was significant (χ(2)=29.839, P<0.05).There was also a significant difference between the constituent ratio of csPCa in the score of 3+1 and 4 (χ(2)=15.286, P<0.01).The positive rate of DCE in cases of PI-RADS V2 overall score 3,3+1 and 4 was 76.4%(107/140).The positive rate of DCE incases of DWI score 3 and 4 were 71.0%(44/62), 80.8%(63/78),respectively. Conclusion: DCE has a certain value in PI-RADS V2 due to its high positive rate in the detection of prostate cancer in peripheral zone.DCE is helpful to DWI score 3 to improve the detection rate of csPCa.The PI-RADS V2 overall score 3+1 and 4 in the peripheral zone maybe need to be distinguished due to the different detection of csPCa.