PI-RADS is an

acronym An acronym is a type of abbreviation consisting of a phrase whose only pronounced elements are the initial letters or initial sounds of words inside that phrase. Acronyms are often spelled with the initial Letter (alphabet), letter of each wor ...

for Prostate Imaging Reporting and Data System, defining standards of high-quality clinical service for multi-parametric

magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ...

(mpMRI), including image creation and reporting.

History

In 2007, the AdMeTech Foundation's International Prostate MRI Working Group convened the key global experts, including members of th
European Society of Urogenital Radiology
(ESUR) and the

American College of Radiology The American College of Radiology (ACR), founded in 1923, is a professional medical society representing nearly 40,000 diagnostic radiologists, radiation oncologists, interventional radiologists, nuclear medicine physicians and medical physicists ...

(ACR). In March 2009 in Vienna an ESUR Prostate MRI Committee was formed, with the aim to produce minimal and maximal standards for acquisition and reporting of prostate MRI. This standardization was endorsed by the results of a consensus meeting in London in December 2009 Dr. Jelle Barentsz published with the ESUR Prostate MRI Committee the first PI-RADS (v.1) version in December 2011. Following this initiative the ACR, ESUR, and the AdMeTech Foundation formed a Joint Steering Committee, and by 2016 published a second version of PI-RADS (v.2) in European Urology. This paper enabled acceptance of the urologists of prostate MRI and was awarded “Best clinical scientific paper of 2016 in European Urology”. In 2019 the PI-RADS Steering Committee published an updated version: PI-RADS v2.1.

Purpose

The aim of prostate MRI using PI-RADS is to assess the risk of clinically significant prostate cancer being present. Furthermore, the PI-RADS v2 system is designed to standardize prostate MRI.

Performance

Various studies have compared the predictive performance of PI-RADS v1 for detecting significant prostate cancer against either image-guided biopsy results (definitive

pathology Pathology is the study of disease. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in the context of modern medical treatme ...

) and/or prostatectomy specimens (

histopathology Histopathology (compound of three Greek words: 'tissue', 'suffering', and '' -logia'' 'study of') is the microscopic examination of tissue in order to study the manifestations of disease. Specifically, in clinical medicine, histopatholog ...

). In a 2015 articles in the Journal of Urology, Thompson reported multi-parametric MRI detection of significant prostate cancer had sensitivity of 96%, specificity of 36%, negative predictive value and positive predictive values of 92% and 52%; when PI-RADS was incorporated into a multivariate analysis (PSA, digital rectal exam, prostate volume, patient age) the area under the curve (AUC) improved from 0.776 to 0.879, p<0.001. A similar paper in European Radiology found that when correlated with histopathology, PI-RADS v2 correctly identified 94-95% of prostate cancer foci ≥0.5 mL, but was limited for the assessment of GS ≥4+3 (significant) tumors ≤0.5 mL; in their series, DCE-MRI offered limited added value to T2WI+DW-MRI. Other applications for which PI-RADS may be useful include prediction of termination of Active Surveillance due to

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

progression/aggressiveness, detection of extraprostatic extension of prostate cancer, and supplemental information when considering whether to re-biopsy patients with a history of previous negative biopsy. PI-RADS v2 is designed to improve detection, characterization and risk stratification in patients suspected of prostate cancer with a goal of better treatment decisions, improved outcomes and simplified reporting.

References

{{Reflist Medical imaging Prostate cancer Magnetic resonance imaging Radiology