Abstract
OBJECTIVES: To propose an easy-to-use binary scoring system for background signal intensity changes in prostate MRI that may affect diagnostic image interpretation and to evaluate its impact on cancer detection. MATERIALS AND METHODS: This retrospective single-center study included 200 patients. Four readers independently assigned background scores of A or B according to the proposed scoring system and assessed the presence or absence of cancer. Light's kappa was used to evaluate inter-reader agreement on the score and on the presence of clinically significant prostate cancer in dependence of the score. Sensitivity and specificity in detecting clinically significant cancer were assessed relative to histology as the gold standard. RESULTS: Due to suboptimal image quality according to the PI-QUAL score, 45 patients were secondarily excluded. Inter-reader agreement on the score was substantial (kappa = 0.62, 95% CI = 0.54-0.71). Inter-reader agreement on the presence of cancer was higher for a background score A (kappa = 0.49, 95% CI = 0.38-0.61) than B (kappa = 0.34, 95% CI = 0.20-0.51). Sensitivity in detecting cancer was high regardless of the background score (86.61% and 89.42% for scores A and B), while specificity decreased markedly in readers with little experience (53.47% and 43.75% for scores A and B), potentially increasing false positives. CONCLUSION: After further validation, the easy-to-use binary background score could enable routine evaluation of normal changes in the peripheral zone, identifying cases with increased false-positive risk among inexperienced readers. CRITICAL RELEVANCE STATEMENT: The easy-to-use binary background score for daily clinical routine allows the communication of potential diagnostic uncertainties in mpMRI image interpretation of the prostate that arise due to normal changes in the peripheral zone, especially for less experienced readers. KEY POINTS: An easy-to-use binary scoring system for addressing background signal intensity changes in the prostate is proposed for MRI interpretation. Inter-reader agreement of the score was substantial, and agreement between readers regarding the presence or absence of cancer was higher for a background score of A than B. The background score could be used to communicate a potential diagnostic uncertainty related to the normal change in the peripheral zone, particularly for less experienced readers.