Performance of Prostate Imaging Reporting and Data System Version 2.1 for Diagnosis of Prostate Cancer: A Systematic Review and Meta-Analysis.

BACKGROUND: The Prostate Imaging Reporting and Data System (PI-RADS) was introduced in 2012 and updated to version 2.1 (v2.1) in early 2019 to improve diagnostic performance and interreader reliability. PURPOSE: To evaluate the diagnostic performance of PI-RADS v2.1 in comparison with v2. METHODS: A systematic review and meta-analysis of the literature was performed using MEDLINE, EMBASE, and Cochrane databases to identify studies evaluating the diagnostic performance of PI-RADS v2.1 for diagnosing clinically significant prostate cancer (csPCa). STUDY TYPE: Systematic review and meta-analysis. SUBJECT: One thousand two hundred forty-eight patients with 1406 lesions from 10 eligible articles. FIELD STRENGTH/SEQUENCE: Conventional MR sequences at 1.5 T and 3 T. ASSESSMENT: Two reviewers independently identified and reviewed the original articles reporting diagnostic performance of PI-RADS v2.1. STATISTICAL TESTS: Meta-analytic summary sensitivity and specificity were calculated using a bivariate random effects model. Meta-analytic sensitivity and specificity between PI-RADS v2 and v2.1 were compared. RESULTS: The pooled sensitivity and specificity of PI-RADS v2.1 were 87% (95% confidence intervals, 82-91%) and 74% (63-82%), respectively. In five studies available for a head-to-head comparison between PI-RADS v2.1 and v2, there were no significant differences in either sensitivity (90% [86-94%] vs. 88% [83-93%], respectively) or specificity (76% [59-93%] vs. 61% [39-83%], respectively; P = 0.37). The sensitivity and specificity were 81% (73-87%) and 82% (68-91%), respectively, for a PI-RADS score cutoff of ≥4, and 94% (88-97%) and 56% (35-97%) for ≥3. Regarding the zonal location, the sensitivity and specificity for the transitional zone only were 90% (84-96%) and 76% (62-90%) respectively, whereas for the whole gland they were 85% (79-91%) and 71% (57-85%). DATA CONCLUSION: PI-RADS v2.1 demonstrated good overall performance for the diagnosis of csPCa. PI-RADS v2.1 tended to show higher specificity than v2, but the difference lacked statistical significance. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 3.