A system of a unified approach to interpreting prostate magnetic resonance imaging according to the PI-RADSv2 guidelines

The experience with magnetic resonance imaging (MRI) used to diagnose prostate cancer (PC) is more than 35 years. Cardinal changes have occurred over that time. The accumulation of experience and the development of technologies have given rise to multiparameter MRI (mpMRI) involving the assessment of both functional and anatomic images. The International MRI Working Group on PC Diagnosis was set up in 2007. The Group has elaborated the basic principles of the standardization and compatibility of MRI studies, which are embodied in the European Society of Urogenital Radiology (ESUR) guidelines as a PI-RADS. The development of this system could create conditions for reducing variations in MRI procedures, interpretation, and mpMRI report forms for PC. The system has realized a scale of rating categories that summarize levels of suspicion or risk and that may be used to select patients for different tactics, such as biopsy or active monitoring. Furthermore, such an optimized approach allows reproducible MRI studies for monitoring during an active follow-up and for the early detection of recurrences. Therefore, PI-RADS enables one to systematize MRI reports and to unify the language of communication between radiologists, urologists, and oncologists.

Owing to the rapid widespread and introduction of the PI-RADS system, it has become possible to analyze its efficiency and to reveal some critical moments. The pooling of the resources of the American College of Radiology (ACR), (ESUR), and the AdMetech Foundation has permitted an Ad Hoc Coordinating Committee, the activity of which is to obtain scientific evidence and to form expert opinions to improve the system, as a result of which an updated PI-RADSv2 was published in 2015. This paper deals with the basic principles of a prostate MRI analysis in accordance with the PI-RADSv2 grades.