Ultrasound carves out integral role in urinary tract

Ultrasound-guided therapy using adult stem cells could expand the modality's role in the diagnosis and management of urethral and bladder conditions. New applications include endoluminal probes, Doppler technology, and 3D imaging capabilities, according to papers presented at the RSNA meeting Sunday.

Urinary incontinence affects many women and is becoming a concern for an increasing number of men. Current treatment standards do not guarantee successful long-term results, however, and they involve either invasive surgery or socially unpleasant solutions.

In a major breakthrough, researchers in Austria have developed an ultrasound-guided technique to repair the urinary tract by injecting stem cells harvested from the patient's own body. They found that almost every patient had been cured one year after the stem cell treatment took place.

In 2002, Dr. Ferdinand Frauscher and colleagues at the Medical University of Innsbruck enrolled 20 female patients aged 36 to 84 with urinary stress incontinence. They underwent left arm biopsies designed to obtain autologous myoblasts and fibroblasts that were then cultured in a lab for six weeks.

Using ultrasound guidance, the researchers injected the stem cells into the patients' urethral wall and sphincter muscles. Transurethral ultrasound showed a significantly increased thickness of the urethra and the rhabdosphincter (p

"This technique seems to have the potential to become an effective and revolutionary treatment of urinary incontinence," Frauscher said.

Ultrasound-guided stem cell injection represents a minimally invasive, cost-effective alternative, according to Frauscher. It can be performed as an outpatient procedure in 15 minutes with local anesthesia and can be done repeatedly. Current treatments such as surgery and collagen injection do not have long-lasting effects. Use of adult diapers as a long-term solution is not only costly but socially embarrassing.

In a different study, the same investigative team evaluated the viability of color Doppler ultrasound for the assessment of urethral function in healthy and incontinent women using an endoluminal probe. They enrolled 10 healthy and 10 incontinent women as well as 10 female patients who underwent incontinence surgery with either Burch colposuspension or prolene mesh suspension techniques.

The investigators confirmed a sliding movement from the distal to the proximal urethra in addition to the known constrictive ability of the female sphincter. This may be useful in evaluating both continent and incontinent subjects.

All patients underwent intraurethral gray-scale ultrasound with a 10-French catheter endoluminal probe and standardized bladder filling of 250 mL. Gray-scale and color Doppler frequencies used were 10 MHz and 9 MHz, respectively.

In a third study, Russian investigators evaluated the possibility of staging bladder tumors preoperatively using 3D endocavity ultrasound. Sixteen patients with bladder cancer confirmed at biopsy underwent 3D power Doppler two weeks before surgery. Using multiplanar and surface rendering reconstructions, the researchers found that "virtual" urethro-cystoscopy images were a sensitive tool for bladder tumor staging and a helpful complement to conventional ultrasound images.