The use of tomographic ultrasound imaging on three-dimensional translabial ultrasound: a diagnostic sign for urethral diverticulum.

INTRODUCTION AND HYPOTHESIS: The objective was to apply tomographic ultrasound imaging (TUI) to diagnose urethral diverticulum (UD) and summarize the specific imaging findings.

METHODS: This was a retrospective analysis of 42 women with a paraurethral cyst. All women underwent a clinical interview, three-dimensional pelvic floor ultrasound and a transvaginal cystectomy between May 2016 and March 2019. UD was defined on TUI if a tract connecting the paraurethral cyst to the urethral lumen was shown in the urethral rhabdosphincter circular muscle in the pelvic floor axial plane. All patients' demographics, history, clinical evaluation and surgical outcomes were reviewed.

RESULTS: On surgical findings, 33 women had a UD and 9 had a Gartner duct cyst. Characteristics of paraurethral cysts described by TUI were consistent with surgical findings in 40 patients (95%). Good agreement was shown by κ test (κ = 0.88, p < 0.001). Of 33 UD patients, the mean age was 45 years and the mean duration of symptoms was 6.5 months. The most common presenting symptom was recurrent urinary tract infection (17, 52%), followed by stress urinary incontinence and a vaginal lump (15, 46%). The mean maximum diameter of 33 UDs was 26 mm (range 8-45 mm). On TUI, one tract, connecting the paraurethral cyst to the urethral lumen, was identified as a gap in the hyperechoic rhabdosphincter muscle circle in the pelvic floor axial plane in 23 UDs (70%); there were two or more tracts in 8 (24%).

CONCLUSIONS: The diagnostic sign to identify urethral diverticulum is a gap in the hyperechoic urethral rhabdosphincter circle formed between the cyst and urethral lumen in the axial plane.