Transperineal and endovaginal ultrasound for evaluating suburethral masses: comparison with magnetic resonance imaging

OBJECTIVE

To evaluate the utility of pelvic floor ultrasound (US) in the detection and evaluation of suburethral masses, using magnetic resonance imaging (MRI) as the reference standard.

METHODS

This was a retrospective analysis of US and MRI scans of all women with a suburethral mass on clinical examination at a single urogynecology clinic over a 13-year period (February 2007 to March 2020). All women were examined using two-dimensional transperineal US (2D-TPUS) with or without three-dimensional endovaginal US (3D-EVUS). All patients underwent unenhanced T1-weighted and T2-weighted MRI, which was considered the reference standard in this study. Presence of a suburethral mass and its size, location, connection with the urethral lumen and characteristics were evaluated on both pelvic floor US and MRI. Agreement between pelvic floor US and MRI was assessed using intraclass correlation coefficients (ICC; 3,1).

RESULTS

Forty women suspected of having a suburethral mass on clinical examination underwent both MRI and US (2D-TPUS with or without 3D-EVUS). MRI detected a suburethral mass in 34 women, which was also detected by US. However, US also identified a suburethral mass in the remaining six women. Thus, the agreement between US and MRI for detecting a suburethral mass was 85% (95% CI, 70.2-94.3%). The ICC analysis showed good agreement between MRI and 2D-TPUS for the measured distance between the suburethral mass and the bladder neck (ICC, 0.89; standard error of measurement (SEM), 3.64 mm) and excellent agreement for measurement of the largest diameter of the mass (ICC, 0.93; SEM, 4.31 mm). Good agreement was observed between MRI and 3D-EVUS for the measured distance from the suburethral mass to the bladder neck (ICC, 0.88; SEM, 3.48 mm) and excellent agreement for the largest diameter of the suburethral mass (ICC, 0.94; SEM, 4.68 mm).

CONCLUSIONS

2D-TPUS and 3D-EVUS are useful in the imaging of suburethral masses. US shows good-to-excellent agreement with MRI in identifying and measuring suburethral masses; therefore, the two modalities can be used interchangeably depending on availability of equipment and expertise. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. - Legal Statement: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.