Thursday, July 8, 2010

Biliary Atresia and Neonatal Hepatitis: Role of Nuclear Medicine

HIDA can be used to differentiate biliary atresia from neonatal hepatitis in an infant with jaundice. Administration of 2.5-5 mg/kg phenobarbitol PO BID for 5-7 days before the study may increase diagnostic accuracy by promoting increased hepatic excretion of the radiotracer.

If biliary excretion is visualized on HIDA, biliary atresia can be excluded. Non-visualization of biliary excretion, however, cannot differentiate biliary atresia from severe neonatal hepatitis (see below). 24-hour delayed images can be obtained in such cases; however, we're fighting against the short half life of 99mTc here and delayed imaging beyond 24 hours may not be useful.

Infants younger than 2 months with biliary atresia usually have normal hepatocyte uptake of the radiotracer. Bilirubin levels > 10 mg/dL and severe neonatal hepatitis may result in decreased hepatic radiotracer uptake and non visualization of biliary excretion, simulating biliary atresia.

References

  • Mettler FA and Guiberteau MJ. Chapter 8. In Essentials of Nuclear Medicine Imaging. Fifth Edition. Saunders, Philadelphia. 2006. p 230.
  • Zukotynski K and Babyn PS. Biliary Atresia. eMedicine. Oct 28, 2009.

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