Biliary Atresia in High Resolution Ultrasonography

Background: Biliary atresia (BA) is the progressive obstructive pathological change in the intra-hepatic and extra-hepatic ducts, causing immediate cirrhosis and leading to death in the first year of life. It is the most common cause of neonatal cholestasis and most common indication for liver transplantation in children. But early diagnosis of biliary atresia and Kasai operation within first 2 months of life may give jaundice-free survival in >60% of these cases. The Case: This was a 48 days old male child who was delivered by normal vaginal delivery, came with prolonged jaundice since for 44 days; birth weight of 3.2 Kg. There was mild hepatomegaly and prominent jaundice. Serum total bilirubin was 11 mg/dl and direct bilirubin was 7.73 mg/dl. Serum ALT was 111U/L and alkaline phosphatase was revealed as 1611, 2202 and 2500 U/L respectively.   PT and APPT were prolonged even after administering vitamin K. HIDA scan was suggestive for extra-hepatic biliary atresia. The equipment used was a Volusion 8 pro ultrasonography system with a curvilinear (2-5 MHz) and linear-array transducer (6-12 MHz). Curvilinear (2-5 MHz) transducer revealed mild diffuse hepatomegaly with small and irregular gallbladder. Linear-array (12-MHz) transducer revealed an irregular wall with distortion of the usual shape of gall bladder with length approximately 12.7 mm (Fig-1). A probable diagnosis of biliary atresia (BA) was found by the “triangular cord (TC) sign” (Fig- 2) (a focal area of increased echogenicity about 5.8 mm in thickness, anterior to portal vein bifurcation). Finer details of gallbladder morphology (length, distortion of shape, and irregularity of wall) and triangular cord (TC) sign were better evaluated with high-frequency linear transducer as compared to the curvilinear probe. Conclusion: Differentiation of biliary atresia from neonatal hepatitis or other causes of infantile cholestatic jaundice is important and the present study summarizes that ultrasonic findings using high-frequency linear transducer as compared to the curvilinear probe can help better in the diagnosis of biliary atresia.