Magnetic resonance urethrography versus conventional retrograde urethrography in the evaluation of urethral stricture: Comparison with surgical findings

摘要

Back ground Urethral stricture means fibrous scarring of the urethra caused by collagen and fibroblast proliferation. Magnetic resonance urethrography was emerging as a new modality for imaging the male urethra. Objectives To evaluate the accuracy of MR urethrography in comparison to the conventional retrograde urethrography (RUG) in the evaluation of urethral stricture in comparison with surgical findings. Design, setting and participants: This prospective study was done in the period from January 2010 to March 2012 including 20 male patients with initial diagnosis of anterior urethral stricture (diagnosed by RUG). Both newly diagnosed and recurrent cases were included regardless of the etiology of stricture. The mean age was 49.6 ± 16.4 years (ranged from 19 to 70). All patients were evaluated by conventional retrograde urethrography (RUG) and magnetic resonance urethrography (MR urethrography). Outcome measurements and statistical analysis Magnetic resonance urethrography images were analyzed, focusing on the signal intensity, location and length of the stricture. Additionally, MR findings were evaluated regarding the urethra proximal to the stricture, the corpora spongiosa surrounding the stricture, adjacent organ injuries, and the associated complications. Data obtained were compared with operative findings in all patients. Results and limitations The mean stricture length as measured by MR urethrography and RGU was 1.32 ± 0.85 and 1.75 ± 1.02 respectively with a significant difference ( p 0.001). The mean intra-operative stricture length was 1.29 ± 0.83. MR urethrography was accurate in 19 patients (95%) while RUG was accurate in 15 patients (75%). This study has some limitations, firstly, a small number of patients are involved in this study, secondly, a 1 T magnet is used and finally, interobserver agreement was not obtained. Conclusion MR urethrography has a higher diagnostic accuracy in the detection of urethral stricture length than conventional RUG, that is crucial for proper selection of treatment modality.