PI-RADS
PI-RADS (Prostate Imaging Reporting and Data System) is a standardized scoring system used in multiparametric magnetic resonance imaging (mpMRI) of the prostate to assess the likelihood of clinically significant prostate cancer. It aims to improve the detection, localization, and risk stratification of prostate cancer by providing a structured reporting framework for radiologists.
The PI-RADS system assigns a score from 1 to 5 to regions of interest (ROIs) within the prostate gland based on the findings observed on different MRI sequences, including T2-weighted imaging, diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging.
- PI-RADS 1: Very low probability of clinically significant cancer. Findings are considered normal or benign.
- PI-RADS 2: Low probability of clinically significant cancer. Findings are more likely benign, but some suspicious features may be present.
- PI-RADS 3: Intermediate probability of clinically significant cancer. Findings are equivocal, meaning that they are neither clearly benign nor clearly malignant. Further evaluation may be considered.
- PI-RADS 4: High probability of clinically significant cancer. Findings are suspicious for malignancy and warrant further investigation, such as a biopsy.
- PI-RADS 5: Very high probability of clinically significant cancer. Findings are highly suggestive of malignancy and typically lead to biopsy and treatment planning.
The latest version of the scoring system is PI-RADS version 2.1. This version was released to clarify certain aspects of image interpretation and to improve the consistency of PI-RADS assessments among radiologists.
The PI-RADS score, along with other clinical factors such as PSA level and digital rectal exam findings, is used by clinicians to guide decisions regarding prostate biopsy, active surveillance, or treatment. The goal of PI-RADS is to reduce unnecessary biopsies while improving the detection of clinically significant prostate cancers that require intervention.