Use of Near Infrared Spectroscopy as an Alternative to Videourodynamics to Detect Detrusor Overactivity in Women With the Overactive Bladder Syndrome

Abstract

To evaluate near infrared spectroscopy as a noninvasive alternative to cystometry for detecting detrusor overactivity in women with overactive bladder (OAB). Although cystometry is considered the "gold standard" investigation for the lower urinary tract, it is invasive. Recently, a noninvasive form of assessment of the lower urinary tract has been introduced using near infrared spectroscopy. This was a prospective pilot study. Women with symptoms of OAB, referred to a tertiary referral one-stop urodynamics clinic were studied. A urodynamic diagnosis was made according to the International Continence Society guidelines. The near infrared spectroscopy monitoring results were analyzed by an independent near infrared spectroscopy Clinical Research Assessor. Both the urodynamics and near infrared spectroscopy assessors reported whether detrusor overactivity was present. Primary outcome measurement was the performance of near infrared spectroscopy as a new diagnostic test. We evaluated the performance of this by calculating the sensitivity and specificity. The clinical usefulness of near infrared spectroscopy was evaluated using positive and negative predictive values. One hundred patients were recruited of whom 95 had traces that could be interpreted. Thirty-one patients were found to have detrusor overactivity on cystometry. Twenty-five of these patients (26%) had detrusor overactivity on near infrared spectroscopy analysis. In 6% of these cases, no near infrared spectroscopy changes identified as suggestive of detrusor overactivity were seen. No detrusor overactivity was detected by cystometry in 64 patients, and in 19% of cases by near infrared spectroscopy. Forty-six patients (48%) had near infrared spectroscopy monitoring events identified as detrusor overactivity but no cystometry changes diagnostic of detrusor overactivity. The results of our study suggest that near infrared spectroscopy is an unreliable method for detecting detrusor overactivity in women with OAB symptoms.