PI-RADS Version 2: A Pictorial Update

Area of Science:

• Radiology
• Oncology
• Medical Imaging

Background:

• The Prostate Imaging Reporting and Data System (PI-RADS) is crucial for standardizing prostate multiparametric MRI interpretation.
• Previous versions aimed to improve the detection of clinically significant prostate cancer.
• An international collaborative effort led to the development of PI-RADS.

Purpose of the Study:

• To introduce and explain the key changes in PI-RADS version 2.
• To provide a guide for assessing the likelihood of clinically significant prostate cancer using multiparametric MRI.
• To promote the consistent application of PI-RADS version 2 in clinical practice.

Main Methods:

• Revision of the original PI-RADS guidelines based on expert consensus and emerging evidence.
• Focus on diffusion-weighted imaging (DWI) with high b values (≥1400 sec/mm²) and apparent diffusion coefficient (ADC) maps for peripheral zone assessment.
• Emphasis on T2-weighted imaging for transition zone lesion assessment.
• Streamlined role for dynamic contrast-enhanced (DCE) MRI as an ancillary tool.

Main Results:

• PI-RADS version 2 prioritizes DWI-ADC parameters for peripheral zone lesion assessment.
• T2-weighted imaging is the dominant parameter for transition zone lesion evaluation.
• DCE-MRI plays a supportive role, particularly for equivocal findings and detecting missed lesions.
• MR spectroscopic imaging is excluded from lesion assessment in PI-RADS version 2.

Conclusions:

• PI-RADS version 2 refines the assessment of clinically significant prostate cancer likelihood using multiparametric MRI.
• The updated system emphasizes specific imaging sequences for different prostate zones.
• PI-RADS version 2 is expected to evolve with further research and technological advancements.