Role of three-dimensional ultrasound in assessment of women undergoing urethral bulking agent therapy

Purpose of review: The technique of three-dimensional ultrasound imaging has been developed over the past 15 years, and has been particularly embraced by the field of obstetrics. More recently, advances have been made in gynecological applications, with promise demonstrated in pelvic floor and lower urinary tract imaging. A clinically useful extension of three-dimensional ultrasound imaging of the lower urinary tract is the assessment of urethral bulking agent therapy, as three-dimensional ultrasound imaging provides an objective means of assessing technical outcomes (i.e. periurethral position, configuration and volume of bulking agent). Our aim is to review recent developments in the use of three-dimensional ultrasound imaging in female incontinence, focusing on its role in the assessment of women undergoing urethral bulking agent therapy for stress urinary incontinence. Recent findings: Three-dimensional ultrasound imaging provides reproducible, affordable and clinically relevant information in the assessment of urethral bulking agent therapy with collagen. Serial, long-term three-dimensional ultrasound imaging assessment has enabled a definition of the technical outcome associated with a durable improvement in continence. The optimal volume varies widely between patients, but a circumferential or horseshoe-shaped periurethral configuration of collagen is strongly correlated with a durable improvement in continence. This finding is in agreement with limited data from a two-dimensional ultrasound assessment of Macroplastique. Summary: Three-dimensional ultrasound imaging provides an objective means of assessing technical outcomes from urethral bulking agent therapy not available previously. The volume and configuration information obtained allows for rational therapeutic decision-making, particularly with regard to determining the need for re-injection and recognizing the failure of an adequate therapeutic trial.