Translabial Three-dimensional Ultrasonography Compared with Magnetic Resonance Imaging in Detecting Levator Ani Defects

Objective: To assess the diagnostic performance of translabial three-dimensional ultrasonography in detecting major levator ani defects in women with pelvic organ prolapse compared with magnetic resonance imaging (MRI) and to assess the interobserver agreement in detecting levator ani defects with translabial three-dimensional ultrasonography.

Methods: In a multicenter cohort study, 140 women indicated for primary surgery of pelvic organ prolapse quantification stage II or more cystocele were included. Patients undergoing mesh surgery or concomitant stress incontinence surgery were excluded. All consenting patients underwent translabial three-dimensional ultrasonography and MRI of the pelvic floor before surgery. Two observers (out of a pool of four observers) assessed translabial three-dimensional ultrasound images; two other observers (out a pool of five observers) assessed MRIs for levator ani muscle damage. In case of disagreement, the images were discussed in a consensus meeting.

Results: Of the 135 scans, 45 major levator ani defects were detected on ultrasonogram (33.3%) and 32 were confirmed at MRI (23.7%). Of the 41 major levator ani defects detected on MRI, nine were missed at translabial three-dimensional ultrasonogram. Sensitivity was 0.78 (32 of 41) (95% confidence interval [CI] 0.65-0.91) and specificity was 0.86 (81 of 94) (95% CI 0.79-0.93) in detecting major levator ani defects with translabial three-dimensional ultrasonography compared with MRI. There was good agreement scoring levator ani defects on translabial three-dimensional ultrasonography, with a κ of 0.67 (95% CI 0.58-0.76); agreement in recognizing major levator ani defects was moderate, with a κ of 0.53 (95% CI 0.37-0.69).

Conclusion: Translabial three-dimensional ultrasonography shows reasonable agreement with MRI in detecting major levator defects. Because of the moderate interobserver agreement, it will be difficult to implement ultrasonography in daily practice.

Clinical Trial Registration: Netherlands Trial Register, www.trialregister.nl, NTR2220.