Transvaginal ultrasound measurement of bladder wall thickness: a more reliable approach than transperineal and transabdominal approaches.

OBJECTIVES To validate transperineal, transabdominal and transvaginal ultrasound (US) techniques to measure bladder wall thickness (BWT). SUBJECTS AND METHODS Women underwent US measurement of BWT at three different anatomical sites: anterior wall, dome and trigone of the bladder by two 'blinded' operators using transabdominal, transperineal and transvaginal approaches at separate visits and by a single operator using transabdominal and transperineal techniques. Bland-Altman analysis was used to determine interobserver reliability for all three techniques and intraobserver reliability for transabdominal and transperineal methods. RESULTS In all, 25 women were scanned. The transperineal US had a high interobserver mean difference when measuring the anterior BWT (-0.34) and a high intraobserver mean difference when measuring the anterior (0.54) and dome BWT (0.33). Transabdominal US had a high interobserver mean difference for all measurements of BWT, and a high intraobserver mean difference when measuring the trigonal thickness (0.56). Transvaginal US had a consistent interobserver mean difference for all three measurements. The transperineal and transabominal approaches had the widest intraobserver and interobserver 95% confidence intervals of the mean difference when compared with the transvaginal approach. CONCLUSIONS Transabdominal and transperineal US for measuring BWT did not have good intraobserver and interobserver reliability for measurement of the three anatomical sites to determine mean BWT. Transvaginal US had good interobserver reliability, thus mean BWT is best measured using the transvaginal approach.