Conjugated jaundice beyond two weeks: the triangular cord sign, an absent or small irregular gallbladder and hepatic subcapsular flow on ultrasound, and no bowel excretion on hepatobiliary scintigraphy point to biliary atresia — surgery (Kasai) before 60 days improves outcome.
Orient first
- Time-critical: early Kasai portoenterostomy improves native liver survival.
- Ultrasound after a 4-hour fast; a normal-sized gallbladder that contracts after a feed argues against atresia.
- Associated splenic malformation syndrome (polysplenia, preduodenal portal vein) in some.
Acquire the study
- High-frequency linear and curvilinear probes; fasting and post-feed gallbladder images; colour Doppler of the hepatic artery.
The manoeuvre
- Triangular cord: echogenic tissue anterior to the portal vein bifurcation ≥ 3–4 mm thick (verify threshold).
- Gallbladder: absent, small (< 1.5 cm) or irregular wall — measure length in mm; contraction after feed.
- Hepatic subcapsular flow on colour Doppler; enlarged hepatic artery.
- Polysplenia, situs anomalies, preduodenal portal vein.
What confirms it
- Intraoperative cholangiography or histology.
What licenses you to exclude it
- Bowel excretion on hepatobiliary scintigraphy essentially excludes biliary atresia.
The classic misread
- A normal gallbladder does not fully exclude atresia.