title: The use of hepatocyte extraction fraction to evaluate neonatal cholestasis.
abstract: OBJECTIVE
  Hepatobiliary scintigraphy is used routinely to evaluate infants with neonatal cholestasis. Hepatobiliary scintigraphy determines biliary patency by detecting radioactivity in the bowel on imaging, in duodenal and gastric aspirates, or all of these. During hepatobiliary scintigraphy, the hepatocyte extraction fraction (HEF) is calculated by deconvolution analysis. Normal values of HEF are more than 90%. It is believed that HEF may predict hepatic dysfunction, because, during hepatobiliary scintigraphy, the radiopharmaceutical used in this test is extracted by the hepatocytes from the blood stream. Therefore, a low value of HEF is seen with more severe hepatocellular disease. The goal of this study was to determine whether HEF has any correlation with synthetic liver function, whether HEF can differentiate obstructive from nonobstructive lesions that cause neonatal cholestasis, and whether HEF can predict the outcome of the different causes of neonatal cholestasis.
  
  
  METHODS
  A retrospective analysis of 68 hepatobiliary scintigraphy results was done in patients with neonatal cholestasis for a period covering 6 years.
  
  
  RESULTS
  The HEF was available in 67 of these 68 patients, with a median value of 25% (range, 3.3% to 100%). The results of synthetic liver function tests (i.e., albumin and prothrombin time) were normal in all infants with neonatal cholestasis. No significant correlation was detected between HEF and the serum levels of total and direct bilirubin, albumin, alkaline phosphatase, and prothrombin time by exploratory data analysis (R = 0.08; small, P > 0.2). The HEF values in different causes of neonatal cholestasis were compared: extrahepatic biliary atresia, neonatal hepatitis, and a miscellaneous category consisting of alpha1-antitrypsin deficiency, ischemic hepatitis, paucity of bile ducts, and others. The outcomes of these diseases were assessed as resolution, continuing disease, transplantation, or death, but no predictive correlation was found with HEF.
  
  
  CONCLUSIONS
  A single determination of HEF is of no value in assessing synthetic liver function (as assessed by albumin and prothrombin time), specific diagnoses, and outcomes in patients with neonatal cholestasis. Therefore, a low isolated value of HEF should not be considered suggestive of poor prognosis and outcome in these patients.
authors.affiliation: Department of Pediatrics, Children's Hospital of Michigan, Detroit, USA. vtolia@med.wayne.edu
authors.forename: V
authors.initials: V
authors.lastname: Tolia
authors.forename: S R
authors.initials: SR
authors.lastname: Kottamasu
authors.forename: D
authors.initials: D
authors.lastname: Tabassum
authors.forename: P
authors.initials: P
authors.lastname: Simpson
mesh_terms: D001659:Biliary Tract / Q000000981:diagnostic imaging*; D001663:Bilirubin / Q000032:analysis; D002779:Cholestasis / Q000097:blood / Q000000981:diagnostic imaging*; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008099:Liver / Q000000981:diagnostic imaging*; D008297:Male; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D012709:Serum Albumin / Q000032:analysis; D017556:Technetium Compounds; D016896:Treatment Outcome
chemical_list: D012709:Serum Albumin; D017556:Technetium Compounds; D001663:Bilirubin