What is the role of cholescintigraphy in diagnosing biliary atresia?
If the patient is properly prepared for the examination, cholescintigraphy can be helpful in excluding the diagnosis of biliary atresia. The other primary differential diagnostic possibility in neonates is severe neonatal hepatitis. The role of scintigraphy is not to diagnose biliary atresia but rather to rule out biliary atresia as a possible diagnosis. To improve the sensitivity of the study, premedication of the neonate with oral phenobarbital (5 mg/kg/day in divided doses for 5 days) is imperative, because it stimulates hepatic activity and increases the ability of the liver to extract the radiopharmaceutical. The importance of therapeutic serum levels of phenobarbital cannot be overemphasized because a scan resulting from poor preparation is indistinguishable from a scan consistent with biliary atresia or neonatal hepatitis. If the radiotracer is not seen in the small bowel, delayed images must be obtained and if small bowel is visualized, biliary atresia is ruled out.
Unfortunately, severe hepatic dysfunction and hepatitis may have a similar appearance to biliary atresia. Additional delayed images should be obtained to assess for activity in the small bowel, which excludes the diagnosis of a high-grade obstruction or biliary atresia.