RESUMO
We retrospectively evaluated the utility of hepatobiliary scintigraphy and various clinical factors in differentiating intrahepatic cholestasis from biliary atresia in 28 consecutive infants with neonatal cholestasis. One millicurie of technetium-labeled diisopropyliminodiacetic acid (DISIDA) was administered intravenously, and images were obtained for up to 24 hours or until gastrointestinal excretion was noted. Nine separate studies in seven infants with biliary atresia were correctly interpreted as showing no gastrointestinal excretion of radionuclide. Of the 21 patients with intrahepatic cholestasis, only nine had gastrointestinal excretion on the first study; in eight without excretion, a second study was done, and five of these showed gut excretion. All infants with either neonatal hepatitis (six) or inspissated bile syndrome (three) had demonstrable gastrointestinal excretion either on the first or second DISIDA study. However, five of six infants with paucity of intrahepatic bile ducts, two of six infants with cholestasis secondary to total parenteral nutrition, and one infant with cholangiolitis did not show evidence of gastrointestinal excretion. The mean birth weight, mean gestational age, and mean weight at study were significantly greater (P less than 0.005) for infants with biliary atresia without excretion than for infants with intrahepatic cholestasis without excretion. The mean direct bilirubin concentration was 6.0 mg/dL for both infants with biliary atresia and infants with intrahepatic cholestasis without excretion; however, infants with excretion had a significantly lower (P less than 0.02) mean direct bilirubin value of 3.4 mg/dL. Excretion was noted in four infants with total bilirubin values greater than 10.0 mg/dL. The absence of gut excretion on the first DISIDA study was 100% sensitive but only 43% specific for biliary atresia. In infants without gut excretion of DISIDA, birth weight greater than 2200 g was 100% sensitive and 92% specific for biliary atresia. We conclude that DISIDA scanning, together with clinical data, is useful in differentiating extrahepatic from intrahepatic cholestasis. The absence of gut excretion on the first DISIDA study does not necessarily indicate extrahepatic obstruction; the study should be repeated if the diagnosis is not clear.