Value of contrast-enhanced colosonography in the assessment of anorectal malformations

BACKGROUND: Anorectal malformations are common congenital anomalies. Accurate preoperative imaging of fistulous connections is crucial for surgical planning. Traditional imaging uses ionizing radiation and often requires sedation. Contrast-enhanced colosonography, based on the application of ultrasound contrast agents, has been developed to overcome these limitations while still providing high-resolution structural information for the evaluation of anorectal malformations. The indications of laparoscopically assisted anorectoplasty for recto-bulbar urethral fistulas remain debated. OBJECTIVES: This study aimed to evaluate the diagnostic accuracy of contrast-enhanced colosonography in detecting anorectal malformations and its value in guiding surgical approach selection. MATERIALS AND METHODS: The diagnostic performance of preoperative contrast-enhanced colosonography and fluoroscopic colostography was compared in 72 cases, with surgical findings serving as the reference standard. Additionally, the relationship between surgical approach and the data from recto-urethral fistula was evaluated. RESULTS: Contrast-enhanced colosonography showed higher sensitivity for fistula detection rate than fluoroscopic colostography (98.6% vs. 83.3%, P<0.001). Concordance with surgical anatomy was 98.6% for contrast-enhanced colosonography, while 73.6% for fluoroscopic colostography. Among patients with recto-bulbar urethral fistula, a pouch-perineum (P-P) cutoff value of 23.5 mm (sensitivity 66.7%, specificity 76.0%) yielded an area under the curve of 0.747 (P=0.01, 95% CI 0.589-0.904). CONCLUSION: Contrast-enhanced colosonography appears to be a safe, effective, and versatile method for obtaining critical preoperative structural information in patients with anorectal malformations. For patients with recto-urethral fistulas, contrast-enhanced colosonography enables further differentiation between recto-membranous and recto-bulbar urethral fistulas. In specified cases, the P-P measurement may be helpful in selecting the appropriate surgical approach.