Imaging description

A three-week-old boy presented with persistent jaundice, dark urine, and light stool. Laboratory evaluation demonstrated hyperbilirubinemia. An ultrasound (US) of the liver showed normal size and echotexture of the liver. The gallbladder was markedly hypoplastic. The common bile duct could not be localized.

A hepatobiliary iminodiacetic acid (HIDA) scan was obtained after intravenous injection of technetium-99 m-HIDA Choletec with dynamic scans over the region of the abdomen in the anterior projection up to 60 minutes as well as static anterior and posterior views at four and 24 hours post injection (Fig. 47.1). Early scans demonstrated rapid uptake of the radiopharmaceutical by the liver, suggesting good hepatocellular function. However, no tracer excretion into the bile ducts or small bowel was seen at 24 hours post injection, suggesting extrahepatic biliary obstruction.

Importance

Congenital biliary atresia occurs with an incidence of 1/10000 to 1/15000 live births in the USA. The etiology is unknown, although infection/inflammation and autoimmune reactions may play a significant role. Girls are more commonly affected than boys and the disease is more common in Asian populations. Patients with biliary atresia can be subdivided into two groups: those with isolated biliary atresia (postnatal form), which accounts for 65–90% of cases, and patients with associated situs inversus or polysplenia with or without other congenital anomalies (fetal/embryonic form), comprising 10–35% of cases.