Reply to Erik Rud and Eduard Baco's Letter to the Editor re: Re: Jeffrey C. Weinreb, Jelle O. Barentsz, Peter L. Choyke, et al. PI-RADS Prostate Imaging - Reporting and Data System: 2015, Version 2. Eur Urol 2016;69:16-40.

Importantly, PI-RADS v.2 only addresses the detection of significant prostate cancer (PCa) in patients with clinical suspicion for PCa in the prebiopsy or postbiopsy setting. It does not address the use of MRI for detection of suspected recurrent PCa following therapy, for which DCE is thought to be important, or of progression during active surveillance. A major goal of PI-RADS v.2 was to simplify the acquisition, interpretation, and reporting of prostate mpMRI data. In their letter, Rud and Baco question the necessity for inclusion of DCE in routine mpMRI for the detection of clinically significant PCa. As they point out, omission of DCE would not only simplify and shorten the examination but also eliminate the cost and potential risk of injection of a gadolinium-based contrast agent. In fact, DCE was among the most challenging issues for members of the PI-RADS Steering Committee that built PI-RADS v.2 over 3 yr, and it reflects in part the challenge of making any recommendation in the face of changing and evolving knowledge. An explanation is certainly warranted. In 2012, when the PI-RADS Steering Committee began its work, DCE was almost universally considered to play a critical role in prostate mpMRI. On the basis of past experience and peer-reviewed scientific publications, most