Evaluation of MRI for diagnosis of extraprostatic extension in prostate cancer

Purpose To assess the ability of magnetic resonance imaging (MRI) to diagnose extraprostatic extension (EPE) in prostate cancer. Materials and Methods With Institutional Review Board (IRB) approval, 149 men with 170 ≥0.5 mL tumors underwent preoperative 3T MRI followed by radical prostatectomy (RP) between 2012–2015. Two blinded radiologists (R1/R2) assessed tumors using Prostate Imaging Reporting and Data System (PI‐RADS) v2, subjectively evaluated for the presence of EPE, measured tumor size, and length of capsular contact (LCC). A third blinded radiologist, using MRI‐RP‐maps, measured whole‐lesion: apparent diffusion coefficient (ADC) mean/centile and histogram features. Comparisons were performed using chi‐square, logistic regression, and receiver operator characteristic (ROC) analysis. Results The subjective EPE assessment showed high specificity (SPEC = 75.4/91.3% [R1/R2]), low sensitivity (SENS = 43.3/43.6% [R1/R2]), and area‐under (AU) ROC curve = 0.67 (confidence interval [CI] 0.61–0.73) R1 and 0.61 (CI 0.53–0.70) R2; (k = 0.33). PI‐RADS v2 scores were strongly associated with EPE (P