Triangular cord sign represents the fibrous ductal remnant of the extrahepatic bile duct in biliary atresia. The objective criterion for positive triangular cord sign has been described as 4 mm thickness or more of the echogenicity along anterior wall of right portal vein on oblique longitudinal scan. In an infant presenting with hyperbilirubinemia and small diminutive gall bladder, sonographic visualization of the triangular cord sign can be invaluable in reliably predicting biliary atresia and helping to decide further management.
The infant underwent a liver biopsy which showed moderate to severe cholestasis and perforating bile ducts consistent with extrahepatic biliary atresia.
During exploratory laparotomy, a cholangiogram performed via a catheter in the remnant gallbladder did not show any tracking of the biliary system. Hence a portoenterostomy or Kasai procedure was performed.