Prospective Validation of an Automated Hybrid Multidimensional MRI Tool for Prostate Cancer Detection Using Targeted Biopsy: Comparison with PI-RADS-based Assessment.

Purpose To evaluate the use of an automated hybrid multidimensional MRI (HM-MRI)-based tool to prospectively identify prostate cancer targets before MRI/US fusion biopsy in comparison with Prostate Imaging and Reporting Data System (PI-RADS)-based multiparametric MRI (mpMRI) evaluation by expert radiologists. Materials and Methods In this prospective clinical trial (ClinicalTrials.gov registration no. NCT03585660), 91 male participants (mean age, 65 years ± 8 [SD]) with known or suspected prostate cancer underwent 3-T MRI with a conventional mpMRI protocol and HM-MRI followed by subsequent biopsy between August 2018 and March 2023. Using the HM-MRI tool, tissue composition was calculated using a three-compartment model, and suspected prostate cancer regions with elevated epithelium (>40%) and reduced lumen (<20%) meeting the minimum size requirement of 25 mm² were identified. Up to two additional biopsy targets per participant were automatically selected with the HM-MRI tool in addition to the biopsy targets selected based on an expert radiologist's mpMRI interpretation (≥PI-RADS 3) using an MRI/US fusion biopsy device. Additional 12-core transrectal US-guided sextant random biopsy cores were also obtained. Detection of clinically significant prostate cancer (≥Gleason 3+4) was compared between HM-MRI and mpMRI by calculating area under the receiver operating characteristic curve and diagnostic accuracy metrics. Results The diagnostic performance of HM-MRI was either higher than mpMRI or showed no evidence of a difference when compared with mpMRI. On a per-participant basis, HM-MRI had significantly higher accuracy (55% vs 44%; P = .02) and specificity (36% vs 14%: P = .002) than mpMRI. On a per-lesion basis, HM-MRI had significantly higher accuracy (58% vs 39%; P < .001) and positive predictive value (31% vs 22%; P = .004) compared with mpMRI. Only one lesion was missed when using the combination of mpMRI and HM-MRI. On a per-sextant basis, HM-MRI showed significantly better performance than mpMRI for all metrics, including primary end points of the area under the receiver operating characteristic curve (0.76 vs 0.65; P < .001) and accuracy (83.9% vs 79.0%; P = .006). Conclusion This study demonstrates that HM-MRI has the potential to improve MRI/US fusion biopsy results for prostate cancer detection by providing complementary information to PI-RADS-based evaluation by expert radiologists. Keywords: Prostate Cancer, Hybrid Multidimensional MRI, Multiparametric MRI, PI-RADS Clinical trial registration no. NCT03585660 ©RSNA, 2025.