Modified sonourethrography assists urethral catheterization.

Sonourethrography (SUG) is an infrequently used modality to observe the male urethra. We modified SUG to examine the reasons for difficulty in urethral catheterization and to determine a safe approach to resolve these problems. Following retrograde urethral jelly injection, modified SUG (mSUG) was performed in male patients with difficulty in urethral catheterization. mSUG was performed using transcutaneous ultrasonography in patients for whom the catheter became lodged in the penile urethra. In other patients, mSUG was performed using transrectal ultrasonography. We divided the causes of difficult indwelling urethral catheterization into physiological and pathological conditions. With regard to physiological conditions, the urethral catheter became stuck in the bulbous portion, membranous urethra, and prostatic urethra. mSUG distinguished the problematic part of the urethra in real time, and it assisted in overcoming the problem. With regard to pathological conditions, urethral stricture after trauma or surgery was clearly demonstrated in the penile and prostatic portions of the urethra. As with physiological conditions, mSUG images assisted in navigating the catheter through the problematic pathological areas or demonstrated the need to abandon the catheterization. mSUG can visualize the male urethra clearly during urethral catheterization and provide real-time assistance with the procedure.