Technical innovation for noninvasive and early diagnosis of biliary atresia: the ultrasonographic “triangular cord” sign

In this article, we introduce our experience regarding a new and noninvasive diagnostic tool, using ultrasonography, for the early and definite diagnosis of biliary atresia. We have focussed on the ultrasonographic image of the cone‐shaped periportal fibrous mass in infants with biliary atresia since 1992, and have finally identified a triangular or band‐like periportal echogenicity (“triangular cord” sign), mainly cranial to the portal vein. Based on our experience and other reports from Japan and Singapore, the ultrasonographic triangular cord sign is a simple, time‐saving, highly reliable, and definite tool in the diagnosis of biliary atresia from infantile intrahepatic cholestasis, representing a positive predictive value greater than 95%. We have proposed a new diagnostic strategy in the evaluation of infantile cholestasis, with emphasis on the ultrasonographic triangular cord sign.