Intraobserver and interobserver reliability of the three-dimensional ultrasound imaging of female urethral sphincter using a translabial technique

The aim of the study was to assess the interobserver and intraobserver reliability of translabial 3D ultrasound imaging of the urethral sphincter in non-pregnant nulliparous asymptomatic women. A study using a 3D translabial ultrasound on thirty-seven women was performed. Urethral sphincter parameters were measured by the same experienced clinician 2 weeks apart. Multiple axial cross-sectional areas at 1-mm distances were used to calculate urethral sphincter volumes. The same measurements were carried out by a second experienced clinician to assess the interobserver reliability. We found an excellent intraobserver reliability (interclass correlation coefficient, ICC > 0.8) and good interobserver reliability (ICC > 0.6). The described technique using multiple axial cross-sectional areas at set distances and a translabial approach is a reliable and accurate tool in the evaluation of the urethral sphincter. This should be used instead of mathematical formulas as the urethral sphincter is not a uniform geometrical sphere. The technique and values reported may help clinicians in the assessment of women with lower urinary tract disorders.