TRIANGULAR CORD - A SONOGRAPHIC FINDING APPLICABLE IN THE DIAGNOSIS OF BILIARY ATRESIA

Biliary atresia (BA) is characterized by luminal obstruction of the ex trahepatic bile duct with fibrous remnants. The authors reviewed ultra sonographic examinations of the fibrous tissue in the bifurcation of t he portal vein at the porta hepatis and identified the triangular- or tubular-shaped echogenic density, the so-called ''triangular cord'' (T C), in the vicinity of the portal vein on a transverse or longitudinal scan. In this prospective study, the authors investigated whether TC was useful in the noninvasive diagnosis of biliary atresia in 18 infan ts who had persistent neonatal jaundice. This was done by comparing th e ultrasonographic examination with the histopathologic examination (H PE) of liver specimens obtained from a needle biopsy. The TC was ident ified in nine patients, all of whom were confirmed to have BA by HPE. The TC was not observed in the other nine patients, who had neonatal h epatitis (NH). The mean size of the TC was 13 mm (wide) x 6 mm (thick) (width range, 5 to 21 mm; thickness range, 4 to 12 mm). The diagnosis of BA was confirmed at the time of Kasai hepatoportojejunostomy in ei ght of the nine patients whose TC was noted by ultrasonography (US). T he other patient was discharged because his parents refused the operat ion; he died of liver failure at 15 months of age. The nine patients w ith absent TC were treated medically for NH. Eight of them improved cl inically. The other, diagnosed to have NH by needle and wedge liver bi opsies, was reexamined 40 days after the initial examination because o f worsening jaundice. A 18 x 12-mm TC was visualized ultrasonographica lly. Additionally, a percutaneous liver biopsy specimen showed BA with severe portal fibrosis and ductal proliferation. The patient underwen t a Kasai hepatoportoentarostomy. On the basis of these results, the a uthors conclude that TC is a very specific ultrasonographic finding, r epresenting the fibrous cone at the porta hepatis, and is a useful too l in the noninvasive diagnosis of BA. However, early exploration or cl ose US follow-up is recommended for any patient suspected of having BA clinically, even if a liver biopsy confirms the NH. Copyright (C) 199 6 by W.B. Saunders Company