Contrast‐Enhanced Ultrasound: A Real‐Time, Noninvasive, Radiation‐Free Method for Intraoperative Male Urethral Fistula Assessment

Abstract

ObjectivesTo evaluate the feasibility of intraoperative transurethral contrast‐enhanced ultrasound for the assessment of male urethral fistulas.MethodsPatients 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.ResultsThirty‐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.ConclusionsTransurethral 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.