Intracavitary Contrast-Enhanced Ultrasound Combined with Pelvic FloorUltrasound: A Real-Time, Non-Invasive, Radiation-Free Method for AssessingVesicovaginal Fistulas

Objective To evaluate the diagnostic efficacy of transperineal pelvic floor ultrasound combined with intracavitary ultrasound in the assessment of vesicovaginal fistula (VVF). Methods A total of 17 patients suspected of VVF who were referred to Jinhua Central Hospital between March 2015 and May 2025 underwent transperineal pelvic floor ultrasonography using a three-dimensional intracavitary volumetric ultrasound probe. A 1:50 dilution of SonoVue contrast agent was injected into the bladder via catheter, and the presence of fistulous communication between the bladder and vagina was dynamically observed in two-dimensional harmonic imaging mode. Three- dimensional Render mode was used to reconstruct images for visualization of the fistula’s size, number, and anatomical location. In addition, three-dimensional ultrasound tomography was employed to measure the distance between the lateral opening of the bladder and the ureteral orifice of the VVF. The ultrasound findings were subsequently compared with surgical observations. Results Under intracavitary ultrasound with contrast enhancement, all 17 patients were diagnosed with VVF within 5–15 seconds of contrast injection, and all demonstrated an abnormal communication between the posterior wall of the bladder and the anterior wall of the vagina. All cases presented with a single VVF; 9 were located at the bladder neck or trigone, with a mean fistula diameter of 8.7 ± 4.9 mm. The mean distances from the VVF to the right and left ureteral openings were − 9.2 ± 2.3 mm and − 8.1 ± 2.1 mm, respectively, while the mean distance from the VVF to the bladder neck was 7.3 ± 1.7 mm. Among these, 8 cases were classified as high VVFs, with a mean fistula diameter of 10.4 ± 7.1 mm. The mean distances from the VVF to the right and left ureteral openings were 27.1 ± 14.0 mm and 28.8 ± 15.4 mm, respectively. No significant difference was observed between high and low VVFs in terms of distance from the left or right ureteral openings (P > 0.05). The ultrasound findings were consistent with intraoperative observations. Conclusion Transperineal pelvic floor ultrasound combined with intracavitary ultrasound provides accurate diagnosis and localization of VVF. The proposed four-step standardized ultrasound protocol demonstrates strong clinical applicability and potential for widespread adoption.