A comparison of sonourethrography and retrograde urethrography in evaluation of anterior urethral strictures.

AIM: This prospective study was undertaken to evaluate the abnormalities of the male anterior urethra using high-resolution ultrasound (sonourethrography) and to compare the efficacy with that of retrograde urethrography (RGU) using operative findings as the gold standard.
MATERIALS AND METHODS: Seventy patients with symptoms of lower urinary tract obstruction underwent RGU followed by sonourethrography. The sonologist was blinded to the findings of RGU. The parameters studied were compared with the intra-operative findings as gold standard, and the sensitivity, specificity and overall accuracy for the procedures were calculated. Chi-square test and kappa statistics were used where appropriate.
RESULTS: All patients found to have urethral stricture disease by RGU were also detected by sonourethrography and confirmed intra-operatively. In the estimation of stricture length, RGU showed a lower sensitivity (60-80%) for lengths 1-4 cm, compared with sonourethrography (73.3-100%). Spongiofibrosis was detected by sonourethrography with a sensitivity of 77.3-83.3%. All the false tracts and calculi detected at sonourethrography were confirmed at surgery, whereas RGU showed a low sensitivity in their detection. The complications encountered during the procedures were pain, urethral bleeding and contrast intravasation. The frequency of pain during RGU was greater (p < 0.001); however, the difference in frequency of bleeding after the two procedures was not significant (p < 0.5).
CONCLUSION: RGU and sonourethrography are equally efficacious in detection of anterior urethral strictures. Further characterization of strictures in terms of length, diameter and periurethral pathologies, like spongiofibrosis and false tracts, is done with greater sensitivity using sonourethrography as compared with RGU, with the added benefit of lower incidence of complications. Copyright 2004 The Royal College of Radiologists