The purpose of this study was to determine the role of MR imaging in the diagnosis of urethral diverticula in women.

In 20 patients (mean age, 47 years), MR imaging was performed (1.5-T); unenhanced T1-weighted and T2-weighted images and contrast-enhanced T1-weighted images were obtained. MR imaging findings were compared with findings on urethrograms (including voiding cystourethrograms or double balloon catheter studies) in 16 patients, urethroscopic findings in 18, and surgical findings in 13. MR images were assessed for the presence, size, number, and location (anterior or posterior to the urethral lumen and relationship to the neck of the bladder) of diverticula, visualization of ostia, and presence of any concomitant complications. Sixteen of 20 patients had urethral diverticula: uncomplicated (simple) urethral diverticula in 13 patients; a diverticulum with a stone in one; a diverticulum with chronic granulation in one; and a diverticulum with adenocarcinoma in one. In the remaining four patients, the diagnoses included Gartner's duct cyst (one) and paraurethral cyst (one); urethras were deemed to be normal in two.

In 13 patients who had surgery, MR images correctly showed the presence or absence of diverticula, whereas urethrography was correct in nine (69%) and urethroscopy in 10 (77%). Compared with surgical findings (20 diverticula in 12 patients), MR images depicted 14 (70%) of 20 diverticula and urethrography and urethroscopy each depicted 11 (55%) of 20. The ostium of the diverticulum could not be identified on MR images. The use of MR contrast material did not contribute to lesion detection, but the enhanced images were superior to unenhanced images in showing granulation tissue and carcinoma, although they did not help in their differentiation.

MR imaging is accurate for showing urethral diverticula, but owing to its high cost, it should be considered only when urethroscopic or urethrographic findings are equivocal or when patients are unable to undergo these procedures and clinical findings strongly suggest a urethral diverticulum.