The normal post-surgical anatomy of the male pelvis following radical prostatectomy as assessed by magnetic resonance imaging.

The magnetic resonance imaging (MRI) appearances of recurrent prostate cancer following radical prostatectomy have been documented in the radiology literature; however little has been written on the range of normal post-operative appearances. Common routes of surgical access for radical prostatectomy include retropubic and transperineal, although newer minimally invasive methods are gaining increasing acceptance. Specifically the range of appearances of the anastomotic site, the prostatic bed, the position of the bladder base, periurethral tissue, levator sling, rectum and residual seminal vesicles (if present) are demonstrated. A non-enhancing low signal nodule is frequently seen at the vesicourethral anastomosis or within the seminal vesicle remnant and usually represents fibrosis. Appearances following different surgical accesses do not differ tremendously, although the retropubic fat pad is reduced or absent following a retropubic approach. Anterior rectal-wall scarring may be present following a transperineal approach. Other post-surgical findings that may mimic disease include a lymphocoele and injected bladder-neck bulking agent. Many patients referred for MRI following radical prostatectomy will have a pathological study showing disease recurrence, although in non-pathological studies the radiological features can differ significantly. It is important for the radiologist to be aware of the spectrum of normal post-surgical appearances so not to confuse these with locally recurrent disease.