To evaluate the feasibility of intraoperative transurethral contrast-enhanced ultrasound for the assessment of male urethral fistulas.
Patients in a prospective database who underwent intraoperative two-dimensional ultrasound, transurethral saline-enhanced ultrasound, and contrast-enhanced ultrasound between January 2017 and July 2022 were included. All patients were clinically diagnosed with urethral fistulae (UF) in the outpatient setting based on clinical presentations, traditional two-dimensional ultrasound, and/or other imaging modalities and confirmed during surgical repair. Dynamic videos of the scans were independently analyzed by two experienced ultrasonologists.
Thirty-nine patients with an average age of 51 years were included. The UF were located in the anterior urethra in 22 (56.4%) patients and in the bulbar urethra in 14 (63.6%) patients. UF were located in the posterior urethra in 17 (436%) patients and in the prostatic urethra in 13 (76.5%) patients. Contrast-enhanced ultrasonography revealed UF in all patients. In patients with anterior UF, saline-enhanced ultrasound images did not show a UF in 15 (68.2%, 15/22) patients, 13 (86.7%, 13/15) of whom had fistulae with diameters <3 mm. Saline-enhanced ultrasound images did not reveal posterior UF in 13 (76.5%, 13/17) patients. The fistula diameters in eight (61.5%, 8/13) patients were <3 mm. The duration for contrast-enhanced ultrasonography was approximately 3 minutes. The duration for surgical repair was approximately 2 hours.
Transurethral contrast-enhanced ultrasound is a real-time, noninvasive, and radiation-free method that allows intraoperative imaging and accurate assessment of male UF. Its sensitivity is higher than that of both two-dimensional ultrasound and transurethral saline-enhanced ultrasound. The location, size, and course of the fistulae can be clearly seen due to greater contrast during contrast-enhanced ultrasound.