Evaluation of the triangular cord sign in the diagnosis of biliary atresia

Background. Infantile cholestasis continues to represent a diagnostic challenge. It is very important to diagnose surgically correctable disorders, such as biliary atresia, in a timely manner to prevent progressive damage to the liver. It has been recently suggested that the triangular cord (TC) sign is a simple and useful tool in the diagnosis of biliary atresia. Methods. We prospectively studied 65 infants presenting with conjugated hyperbilirubinemia (age range: 32-161 days). All patients underwent ultrasonographic examination with a 7.0-MHz transducer (Acuson, Mountain View, CA). The TC was defined as a triangular, or tubular, echogenic density seen immediately cranial to the portal vein bifurcation. Results. The TC sign was identified in 25 infants, and all of them had histologic features suggestive of biliary atresia; the diagnosis was confirmed at surgery by gross morphology of hepatobiliary system, and liver biopsy, with or without intraoperative cholangiogram. Among the 40 patients who did not have the TC sign, 6 had paucity of the intrahepatic bile ducts. Three had alph-1-antitrypsin deficiency, and 31 had neonatal hepatitis. None of the 40 patients who did not have the TC sign developed acholic stools. Seven patients with biliary atresia were followed by ultrasonographic examination for 6 months after the Kasai procedure. The TC sign disappeared in all patients after the surgery; however, the TC sign reappeared in 3 patients who developed progressive cholestasis after the procedure. Conclusion. The TC sign is a simple, timesaving, and reliable diagnostic tool in the evaluation of infants with infantile cholestasis. The TC sign may also prove to be helpful in following patients after hepatoportoenterostomy. We suggest a new diagnostic strategy for patients suspected to have biliary atresia. When the TC sign is visualized, the patient should undergo intraoperative cholangiogram to confirm the diagnosis of biliary atresia, reserving percutaneous liver biopsy for those patients in whom the TC sign could not be detected.