A novel four-step protocol using intracavitary contrast-enhanced ultrasound combined with pelvic floor ultrasound for the diagnosis and preoperative planning of vesicovaginal fistulas.

BACKGROUND: Vesicovaginal fistula (VVF) is a debilitating condition that significantly impairs quality of life. Accurate preoperative assessment of fistula characteristics is crucial for surgical planning. We aimed to evaluate the diagnostic efficacy of a novel four-step protocol combining transperineal pelvic floor ultrasound with intracavitary contrast-enhanced ultrasound (IC-CEUS) for VVF assessment.

METHODS: This retrospective study included 17 patients with suspected VVF treated at our institution between March 2015 and May 2025. All patients underwent the proposed four-step IC-CEUS protocol: (1) two-dimensional (2D) fan scanning; (2) dynamic observation of contrast flow after intravesical injection of diluted SonoVue; (3) three-dimensional (3D) Render mode reconstruction; and (4) 3D tomographic ultrasound imaging (TUI) for quantitative distance measurements. Findings were compared against intraoperative observations.

RESULTS: IC-CEUS achieved a 100% diagnostic rate for VVF in all 17 patients, compared to only 53% (9/17) with conventional 2D ultrasound. Nine low VVFs (at the bladder neck or trigone) and eight high VVFs (above the interureteric ridge) were identified. High VVFs were located significantly farther from the bilateral ureteral orifices than low VVFs (both P < 0.001). All preoperative IC-CEUS findings were confirmed intraoperatively, and postoperative contrast-enhanced ultrasound verified successful closure in 16 patients.

CONCLUSIONS: The standardized four-step IC-CEUS protocol provides a real-time, non-invasive, and radiation-free method for accurate VVF diagnosis, precise localization, and comprehensive preoperative evaluation, offering valuable guidance for surgical planning.