Ultrasound: a noninvasive screening test for detrusor instability

OBJECTIVE: To determine whether transvaginal ultrasound measurement of bladder wall thickness can be used as a screening test for detrusor instability in women with urinary symptoms. DESIGN: A blinded prospective study. SETTING: A London teaching hospital. PARTICIPANTS: One hundred and eight-four symptomatic women presenting to a urodynamic clinic. MAIN OUTCOME MEASURE: The detection of detrusor instability by means of videocystourethrography (VCU) and ambulatory urodynamics in women with a mean bladder wall thickness of greater than 5 mm measured by transvaginal ultrasound. RESULTS: One hundred and eight women had a mean bladder wall thickness of greater than 5 mm. Ninety-four percent (102) of these women had detrusor instability either when undergoing VCU or ambulatory urodynamics. Seventeen women had a bladder wall thickness of less than 3.5 mm of whom three were found to have detrusor instability on VCU. CONCLUSION: The measurement of a mean bladder wall thickness greater than 5 mm with transvaginal ultrasound is a sensitive screening method for diagnosing detrusor instability in symptomatic women without outflow obstruction.