Purpose or Case Report: The purpose of this educational exhibit is to:
1.Review the embryology, classification, and imaging features of anorectal malformations (ARMs).
2.Review the indications and techniques of Contrast-enhanced colosonography (CeCS) in pediatric patients with ARMs.
3.Provide sample cases and clinical courses of patients with specific ARMs.

Anorectal malformations(ARMs) are a spectrum of congenital anomalies involving abnormal development of the distal rectum and anus, leading to an interruption or misconnection of the normal passage between the rectum and the perineum. The condition occurs in about 1 in 5,000 live births and can range from mild to complex. Children with ARMs require preoperative imaging to assess the presence and location of a fistula. Identifying the location of these fistulas is crucial for surgical planning.

Contrast-enhanced colosonography (ceCS) has emerged as a valuable tool in diagnosing pediatric ARMs, offering superior anatomical visualization and assessment compared to traditional imaging techniques like fluoroscopy, providing more sensitive and specific evaluation of fistula with real-time contrast filling. CeCS avoids ionizing radiation, and ultrasound contrast agents have a high safety profile with low incidence of adverse events compared to other contrast agents.

Contrast-Enhanced colosonography (CeCS) technique should include survey greyscale ultrasound examination of the pelvis to assess for adequate window. Lumason, the ultrasound contrast agent, is prepared and injected into a bag of saline, with a ratio of 1:500 mL. The mucous fistula is examined, and a small Foley catheter is inserted by the radiologist, then balloon is inflated to create a seal. Contrast is then instilled by gravity drip, and perineal structures are imaged through three standard approaches- transabdominal, transperineal and posterior sagittal approaches.

As well as reviewing the topics above, this review will also provide examples of ARM cases demonstrating high, intermediate, and low fistulas seen on CeCS.

Overall, CeCS enhances the diagnostic accuracy and management of pediatric ARMs. By providing detailed anatomical insights and allowing for accurate classification, it plays a critical role in guiding treatment strategies and improving long-term outcomes for affected patients.
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