Biliary atresia (BA) is characterized by a hypoplastic or atretic extrahepatic biliary tree, typically presenting as persistent neonatal jaundice from day one. Abdominal ultrasound and hepatobiliary scans are key diagnostic tools, with ultrasound revealing absent or irregular gall bladder and fibrotic remnants, while a lack of intestinal excretion on hepatobiliary scans confirms BA. Additional anomalies may be present, and premedication with phenobarbital can enhance diagnostic accuracy.

1. Biliary atresia (BA)
Imaging findings

2. Definition
hypoplastic, atretic, or fibrosed
extrahepatic biliary tree

3. Presentation
persistent neonatal jaundice
starting with day 1
with increased conjugated bilirubin

4. Best imaging tools
abdominal ultrasound – suggests diagnosis
hepatobiliary scan – confirms diagnosis

5. MRCP – not reliable
failure to see complete biliary tree in 25-40%
of normal < 3 months age
ERCP – rarely performed
shows no biliary enteric channel

6. Ultrasound
absent or small and irregular gall bladder
absent extrahepatic duct
triangular echogenic cord anterior to portal vein
fibrotic remnant of common bile duct typically anterior to portal bifurcation
 all strongly suggest BA

7. Ultrasound
look for associated anomalies
preduodenal portal vein
malrotation
asplenia
polysplenia

8. Hepatobiliary scan with DISIDA or BRIDA
premedication with phenobarbital 5 days induces liver enzymes
 increases accuracy
gall bladder seen in 25% does not exclude diagnosis

9. Hepatobiliary scan with DISIDA or BRIDA
lack of excretion into intestines on 24h images
 confirms BA or other cause of obstruction
excretion into intestines = BA excluded