Doppler Studies of the Lower Urinary Tract

Abstract

Ultrasound of the lower urinary tract poses problems for the sonographer. Clear views of the pelvis through the abdomen rely on the urine-filled bladder to act as an acoustic window and this is useful for delineating bladder tumours [2] and measuring post-void residuals [14]; however, by filling the bladder its structure is difficult to visualise. The retropubic position of the bladder neck and urethra make transvaginal [15], transrectal [17, 18] and transperineal ultrasound [11] the ideal methods of visualising the bladder and urethra. The transabdominal approach does not reliably image the bladder neck and urethra, particularly in the obese or in women suffering genuine stress incontinence. The transvaginal approach, when used to image urinary leakage into the proximal urethra, should be interpreted with caution, as compression of the urethra can occur [19]. The transrectal approach does not alter any urodynamic parameter, but there can be problems in visualising the bladder neck and urethra if a rectocele is present [18]. The transperineal approach has the advantage of direct contact with the distal end of the urethra, and the proximity of the probe ensures good images of the periurethral structures despite vaginal prolapse [9].