An 8-week-old infant with persistent conjugated hyperbilirubinemia undergoes high-resolution ultrasonography. A triangular echogenic focus is seen anterior to the right portal vein at the porta hepatis, measuring more than 4 mm in thickness. This 'triangular cord sign' supports which diagnosis?
- A Choledochal cyst
- B Biliary atresia ✓
- C Neonatal hepatitis
- D Alagille syndrome
Correct answer: B. Biliary atresia
Explanation
The triangular cord sign represents the fibrotic obliterated extrahepatic bile duct remnant seen as a triangular echogenic density cranial to the portal vein bifurcation; thickness over 4 mm is highly suggestive of biliary atresia. Neonatal hepatitis shows a normal or non-visualised gallbladder without this echogenic cord. Choledochal cyst appears as a cystic structure separate from the gallbladder in the porta hepatis. Alagille syndrome shows paucity of intrahepatic ducts on biopsy, not a triangular echogenic focus on ultrasound.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.