An MRI assessment of prostate cancer local recurrence using the PI-RR system: diagnostic accuracy, inter-observer reliability among readers with variable experience, and correlation with PSA values.

• In this retrospective study, the PI-RR system revealed promising diagnostic performances among five readers with different experience (sensitivity 79-86%; specificity 64-86%; accuracy 79-87%). • The inter-observer reliability among the five readers resulted good or excellent (κ ranges: 0.52-0.77) with an intraclass correlation coefficient of 0.8. • The PI-RR assessment score may facilitate standardisation and generalizability in the evaluation of prostate cancer local recurrence among radiologists.