Purpose: We evaluated interreader agreement with PI-RADS® (Prostate Imaging Reporting and Data System) version 2 for detection of prostate cancer.
Materials and methods: We searched MEDLINE®, Embase® and the Cochrane Library between 2015 and June 3, 2019 to identify original research reporting interreader agreement in the use of PI-RADS version 2. Quality of the retrieved studies was assessed by 2 independent reviewers using the Guidelines for Reporting Reliability and Agreement Studies. Pooled κ for PI-RADS version 2 was calculated, and a head-to-head comparison with version 1 was performed for the available studies. Subgroup analysis was performed according to zonal anatomy (peripheral or transitional zone), cutoff value (4 or higher, or 3 or higher) and specific imaging sequences (T2-weighted, diffusion-weighted and dynamic contrast enhanced). Meta-regression analysis was performed to assess the cause of study heterogeneity.
Results: A total of 30 studies (4,095 patients) were included. Pooled κ of PI-RADS version 2 was 0.61 (95% CI 0.55-0.67). In 4 studies evaluating head-to-head comparisons PI-RADS versions 1 and 2 showed similar pooled κ values (0.61, 95% CI 0.33-0.90 vs 0.68, 95% CI 0.57-0.79; p=0.61). Substantial interreader agreement was noted with a cutoff of 4 or higher (κ=0.61) and moderate agreement was observed with a cutoff of 3 or higher (κ=0.57), peripheral zone (κ=0.64), transitional zone (κ=0.49) and the 3 magnetic resonance imaging sequences (κ 0.42-0.58). Difference in reader experience was the single significant factor affecting study heterogeneity (p=0.01).
Conclusions: PI-RADS version 2 provides substantial interreader agreement in overall scoring in patients with suspicious prostate cancer, with a similar level of agreement to version 1.
Keywords: magnetic resonance imaging; prostate; prostatic neoplasms.