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.