Visibility of MRI prostate lesions on B-mode transrectal ultrasound

Prostate biopsies are usually done with transrectal ultrasound (TRUS) in B-mode (B TRUS) but multiparametric MRI (mpMRI) is the gold imaging standard for the visualization of clinically significant prostate cancer (PCa), since a lowPCa detection rate is reported for B TRUS. The aim of this study was to assess the visibility of MRI lesions on B TRUS and to determine which factors may influence the visibility on B TRUS.

142 men with 148 lesions reported on mpMRI underwent a B TRUS/mpMRI fusion targeted biopsy of the prostate and were included in this retrospective study. During the biopsy, images were obtained and stored in the institution's PACS. These images were reviewed by two radiologists to determine, whether an mpMRI lesion was or was not visible on B TRUS.

Overall 92 from 148 mpMRI lesions (62.2%) were visible on B TRUS. The location of the lesion in the prostate, the PIRADS classification of the lesions and the size of the lesion had no significant influence on the visibility on B TRUS. Only the prostate volume had a significant influence on visibility: in smaller prostates significantly more lesions were visible on B TRUS than in large glands (p+0.041; 45.1 ml vs 54 ml).

The use of newer high-end ultrasound units as well as experience gained from fusion biopsies enables us to see 62.2 % of all suspicious mpMRI lesions on B TRUS. B TRUS images merit a thorough examination during a conventional biopsy setting.