Abbreviated Biparametric Prostate MR Imaging in Men with Elevated Prostate-specific Antigen

Purpose: To determine the diagnostic accuracy for clinically significant prostate cancer achieved with abbreviated biparametric prostate magnetic resonance (MR) imaging in comparison with full multiparametric contrast material-enhanced prostate MR imaging in men with elevated prostatespecific antigen (PSA) and negative transrectal ultrasonography (US)guided biopsy findings; to determine the significant cancer detection rate of biparametric versus full multiparametric contrast-enhanced MR imaging and between-reader agreement for interpretation of biparametric MR imaging. Materials and Methods: In this institutional review board-approved retrospective review of prospectively acquired data, men with PSA greater than or equal to 3 ng/mL after negative transrectal US-guided biopsy findings underwent state-of-the-art, full multiparametric contrast-enhanced MR imaging at 3.0-T including high-spatial-resolution structural imaging in several planes, diffusion-weighted imaging at 0, 800, 1000, and 1400 mm(2)/ sec, and dynamic contrast-enhanced MR imaging, obtained without endorectal coil within 34 minutes 19 seconds. One of four radiologists with different levels of expertise (1-9 years) first reviewed only a fraction of the full multiparametric contrast-enhanced MR images, consisting of single-plane (axial) structural imaging (T2-weighted turbo spin-echo and diffusion-weighted imaging), acquired within 8 minutes 45 seconds (referred to as biparametric MR imaging), and established a diagnosis according to the Prostate Imaging Reporting and Data System (PI-RADS) version 2; only thereafter, the remaining full multiparametric contrast-enhanced MR images were read. Men with PI-RADS categories 3-5 underwent MR-guided targeted biopsy. Men with PI-RADS categories 1-2 remained in urologic follow-up for at least 2 years, with rebiopsy (transrectal US-guided or transperineal saturation) where appropriate. McNemar test was used to compare diagnostic accuracies. To investigate between-reader agreement, biparametric MR images of 100 patients were read independently by all three radiologists. Results: A total of 542 men, aged 64.8 years 6 8.2 (median PSA, 7 ng/mL), were included. Biparametric MR imaging helped detect clinically significant prostate cancer in 138 men. Full multiparametric contrastenhanced MR imaging allowed detection of one additional clinically significant prostate cancer (a stage pT2a, intermediate-risk cancer with a Gleason score of 3+ 4) and caused 11 additional false-positive diagnoses. Diagnostic accuracy for detection of clinically significant cancer of biparametric MR imaging (89.1%, 483 of 542) was similar to that of full multiparametric contrast-enhanced MR imaging (87.2%, 473 of 542). Between-reader agreement of biparametric MR imaging interpretation was substantial (k = 0.81). Conclusion: Biparametric MR imaging allows detection of clinically significant prostate cancer missed by transrectal US-guided biopsy. Biparametric prostate MR imaging takes less than 9 minutes examination time, works without contrast agent injection, and offers a diagnostic accuracy and cancer detection rate that are equivalent to those of conventional full multiparametric contrast-enhanced MR imaging protocols. (C) RSNA, 2017