PI-RADS v2.1 for prostate MRI: current applications, ongoing debates, and synergies with advanced technologies-a narrative review.

BACKGROUND AND

OBJECTIVE

Prostate Imaging Reporting and Data System (PI-RADS) version 2.1 is the current standard for prostate multiparametric magnetic resonance imaging (mpMRI) reporting, aimed at improving diagnostic consistency for clinically significant prostate cancer (csPCa). This review aims to summarize the current applications of PI-RADS v2.1, analyze its diagnostic performance and limitations, and explore emerging synergies with biomarkers, biparametric MRI (bpMRI), artificial intelligence (AI), and advanced quantitative MRI techniques.

METHODS

A comprehensive literature search was conducted in PubMed and Web of Science databases up to December 2025, covering English-language articles on PI-RADS v2.1, prostate MRI, and related diagnostic innovations. Both original research and systematic reviews were considered to provide a balanced overview.

KEY CONTENT AND FINDINGS: Compared with version 2.0, PI-RADS v2.1 refines technical specifications and interpretive criteria, but persistent challenges remain, including inter-reader variability and ambiguous guidance on patient preparation. Integration with prostate-specific antigen (PSA) density helps optimize risk stratification for PI-RADS 3 lesions. The bpMRI pathway offers a contrast-free, time-efficient alternative with comparable diagnostic accuracy. AI, particularly deep learning and radiomics, augments lesion detection, classification, and workflow efficiency, narrowing the experience gap among radiologists. Emerging techniques such as amide proton transfer-weighted imaging, restriction spectrum imaging, and magnetic resonance elastography provide complementary quantitative data that may further improve csPCa detection when combined with PI-RADS v2.1.

CONCLUSIONS

PI-RADS v2.1 has advanced standardization of prostate MRI, but its limitations-especially in patient preparation and transition zone assessment-require attention. Combining PI-RADS with clinical biomarkers and emerging technologies moves toward more precise and personalized diagnosis. Future prospective studies are needed to validate these integrated approaches across diverse clinical settings.