Sonography in the evaluation of the male anterior urethra.

Contrast ascending urethrography is the technique most commonly used to evaluate the male anterior urethra. Sonography of the anterior urethra was prospectively evaluated in 24 consecutive referrals for conventional urethrography. In 11 patients both the sonographic and the contrast urethrograms were considered normal. Both studies demonstrated one or more strictures in nine patients but ultrasound also demonstrated periurethral cuffing in three of these. Sonography demonstrated a mucosal flap missed on the contrast study and also showed that suspected bubbles seen on the contrast study were true urethral filling defects. Diverticula were seen in three contrast studies. Two were demonstrated sonographically but the third, a shallow diverticulum in a patient with a complex stricture, was not seen on the sonogram. Mucosal irregularity was observed in five patients, and lack of urethral distensibility was demonstrated in a further five patients, by both techniques. Reflux into prostatic and Cowper's ducts could not be detected by ultrasound. Sonography offers advantages over conventional urethrography both in terms of abnormalities detected and convenience of the study.