Making the diagnosis of biliary atresia using the triangular cord sign and gallbladder length.

BACKGROUND: To evaluate the accuracy and utility of the triangular cord sign and gallbladder length in diagnosing biliary atresia by sonography.
MATERIALS AND METHODS: Sixty fasted infants with cholestatic jaundice aged 2-12 weeks were examined sonographically using a 5-10 MHz linear array transducer, focusing on the triangular cord sign (as described by Choi et al. [1]), the gallbladder, and ducts. The triangular cord is defined as a triangular or tubular echogenic density seen immediately cranial to the portal vein bifurcation; it represents the fibrotic remnant of the obliterated cord in biliary atresia. The findings were blinded to blood chemistry, (99 m)Tc-DISIDA hepatobiliary scintigraphy, and liver biopsy. Diagnosis of biliary atresia was confirmed at surgery and histology. Non-biliary atresia infants resolved medically. Comparative charges of the various investigations was made.
RESULTS: ++ Twelve infants had biliary atresia, and ten demonstrated a definite triangular cord. The two false-negatives had small or nonvisualized gallbladders. No false-positives were recorded. Gallbladder length ranged from 0-1.45 cm with a mean of 0. 52 cm in biliary atresia compared to a mean of 2.39 cm in nonbiliary atresia infants. (99 m)Tc-DISIDA hepatobiliary scintigraphy showed no excretion (false-positive) in 23 % of nonbiliary atresia cases. Scintigraphy and liver biopsy charges were 2 and 6 times that of sonography, respectively.
CONCLUSION: The triangular cord sign and gallbladder length together are noninvasive, inexpensive, and very useful markers for biliary atresia.