External Validation of a Previously Developed Deep Learning–based Prostate Lesion Detection Algorithm on Paired External and In-House Biparametric MRI Scans

Purpose To evaluate the performance of an artificial intelligence (AI) model in detecting overall and clinically significant prostate cancer (csPCa)-positive lesions on paired external and in-house biparametric MRI (bpMRI) scans and assess performance differences between each dataset. Materials and Methods This single-center retrospective study included patients who underwent prostate MRI at an external institution and were rescanned at the authors' institution between May 2015 and May 2022. A genitourinary radiologist performed prospective readouts on in-house MRI scans following the Prostate Imaging Reporting and Data System (PI-RADS) version 2.0 or 2.1 and retrospective image quality assessments for all scans. A subgroup of patients underwent an MRI/US fusion-guided biopsy. A bpMRI-based lesion detection AI model previously developed using a completely separate dataset was tested on both MRI datasets. Detection rates were compared between external and in-house datasets with use of the paired comparison permutation tests. Factors associated with AI detection performance were assessed using multivariable generalized mixed-effects models, incorporating features selected through forward stepwise regression based on the Akaike information criterion. Results The study included 201 male patients (median age, 66 years [IQR, 62-70 years]; prostate-specific antigen density, 0.14 ng/mL² [IQR, 0.10-0.22 ng/mL²]) with a median interval between external and in-house MRI scans of 182 days (IQR, 97-383 days). For intraprostatic lesions, AI detected 39.7% (149 of 375) on external and 56.0% (210 of 375) on in-house MRI scans (<i>P</i> < .001). For csPCa-positive lesions, AI detected 61% (54 of 89) on external and 79% (70 of 89) on in-house MRI scans (<i>P</i> < .001). On external MRI scans, better overall lesion detection was associated with a higher PI-RADS score (odds ratio [OR] = 1.57; <i>P</i> = .005), larger lesion diameter (OR = 3.96; <i>P</i> < .001), better diffusion-weighted MRI quality (OR = 1.53; <i>P</i> = .02), and fewer lesions at MRI (OR = 0.78; <i>P</i> = .045). Better csPCa detection was associated with a shorter MRI interval between external and in-house scans (OR = 0.58; <i>P</i> = .03) and larger lesion size (OR = 10.19; <i>P</i> < .001). Conclusion The AI model exhibited modest performance in identifying both overall and csPCa-positive lesions on external bpMRI scans. <b>Keywords:</b> MR Imaging, Urinary, Prostate <i>Supplemental material is available for this article.</i> © RSNA, 2024.