Can biliary atresia be diagnosed by ultrasonography alone?

Abstract

The triangular cord sign (TCS) is a specific ultrasonographic finding, reflecting a fibrotic mass at the porta hepatis in biliary atresia (BA). We evaluated whether BA can be diagnosed by ultrasonography alone using 3 findings: TCS, gallbladder length (GBL), and gallbladder contractility (GBC). Subjects comprised 85 infants (median age, 47 days; range, 4-144 days) with cholestatic jaundice who underwent ultrasonographic examination for diagnosis between May 1996 and June 2006. Medical records were reviewed with regard to TCS, GBL, and GBC. Positive findings for BA included TCS >or=3 mm, GBL <15 mm, and GBC <68% (for < 12 weeks) or <25% (for >or=12 weeks). Biliary atresia was diagnosed in 48 patients surgically, with other cholestatic diseases diagnosed in the remaining 37 patients. Triangular cord sign was positive in 41 of 48 infants with BA and negative in 35 of 37 infants without BA. The 7 patients with BA who displayed negative results for TCS displayed positive findings for GBL or GBC. Positive predictive value in the diagnosis of BA was 98% if positive TCS was combined with abnormal gallbladder findings, whereas negative predictive value in diagnosis of BA was 100% if negative TCS was combined with findings of a normal gallbladder. Biliary atresia can be accurately diagnosed by ultrasonography using the findings of TCS combined with GBL and GBC.