Prostate MRI technical parameters standardization: A systematic review on adherence to PI-RADSv2 acquisition protocol

Purpose: The Prostate Imaging-Reporting and Data System has been developed to standardize prostate MRI in terms of acquisition, interpretation and reporting. It received a major revision in late 2014 (PI-RADSv2). Recently, doubts have been raised on imaging facilities adherence to its acquisition protocol. With this systematic review, we assessed adherence to PI-RADSv2 minimum technical specifications in literature, to achieve a better understanding of issues limiting their diffusion. Method: Multiple medical literature databases were extensively searched to retrieve original studies published after January 2016 performing prostate MRI. Information pertaining acquisition protocols and patient enrolment were recorded for analysis. Technical parameters were dichotomized in relation to adherence to the corresponding minimal technical requirements. Results: A total of 150 studies were included for analysis. Only 5% reported every technical parameter specified in the PI-RADSv2 document requirements, none of which completely met guideline specifications. Overall, 19% were in line with PI-RADSv2 for all reported MRI acquisition parameters. The adherence was lowest for T2-weighted frequency in-plane resolution (12%), diffusion-weighted imaging field of view (40%), apparent diffusion coefficient map low b-value (27%) and dynamic contrast-enhanced imaging temporal resolution (43%). Considering its role in image interpretation, it must be highlighted that only 59% of studies reporting diffusion-weighted imaging high b-value follow recommendations. Conclusions: Adherence to PI-RADSv2 minimum technical standards is heterogeneous in the scientific community. Our findings endorse the need for greater diffusion of PI-RADSv2 guidelines to achieve protocol standardization and support the notion that some requirements might benefit from streamlining to improve clinical applicability.