Hepatobiliary scintigraphy and gamma-GT levels in the differential diagnosis of extrahepatic biliary atresia.

Aim: The aim of this paper is to identify extrahepatic biliary atresia (EHBA) as the cause of cholestasis in neonates with prolonged jaundice and thus accelerate the decision for surgical intervention, which is critical for prognosis.
Methods: We retrospectively studied 21 infants (13 girls, 8 boys) aged 2-16 weeks who have undergone( 99m)Tc-mebrofenin iminodiacetate ((99m)Tc-BrIDA) scintigraphy. They were referred because of direct hyperbilirubinemia and jaundice persisting beyond the 2nd postnatal week. They had received phenobarbitone premedication prior to scintigraphy. Dynamic images for 30 min and then static images (if required) at 1, 2 and 24 h postinjection were acquired. Images were evaluated visually and semiquantitatively, by calculating the liver-to-heart (L/H) ratio. Age, L/H ratios, and serum gamma glutamyl transpeptidase (gamma-GT) levels were compared (Mann-Whitney U test) between infants with EHBA (Group A) and infants without (Group B). The L/H ratios were correlated with age in each group and with gamma-GT in the entire population.
Results: A total of 7/21 infants were classified in Group A and 14/21 in Group B. The L/H ratios were significantly lower in Group A. The correlation between L/H ratio and age was negative in EHBA and positive in non-atretic infants. The gamma-GT levels were inversely correlated with the L/H ratios in the entire population, being significantly higher in Group A.
Conclusion: In long-standing neonatal direct hyperbilirubinemia, (99m)Tc-BrIDA scintigraphy and the L/H ratio index seem to give useful information in the differential diagnosis of EHBA, especially when associated with markedly elevated serum gamma-GT levels.