title: Biliary atresia: US diagnosis.
abstract: OBJECTIVE
  To evaluate prospectively the sensitivity of ultrasonography (US) in the diagnosis of biliary atresia (BA), with surgery as the reference standard.
  
  
  METHODS
  After institutional ethical approval and with informed parental consent, 90 consecutive fasting infants with conjugated hyperbilirubinemia underwent detailed US studies performed by a single operator with a 7.5-MHz curvilinear transducer and a 13.5-MHz linear-array transducer. The following features were prospectively recorded: gallbladder morphology, triangular cord sign, presence of a common bile duct, liver size and echotexture, splenic appearance, and vascular anatomy. The operator was blinded to results of other investigations. Sensitivity, specificity, and positive and negative predictive values were calculated for each US variable. BA and non-BA groups were compared by means of the Fisher exact test for categorical variables and an unpaired t test for continuous variables.
  
  
  RESULTS
  Thirty infants (13 male, 17 female) had surgically confirmed BA, and 60 (35 male, 25 female) had other documented causes of neonatal jaundice; the mean ages at US assessment were 48.5 and 52.4 days, respectively (P>.5). Eight US features showed a significant difference between BA and non-BA groups (P<.001, Fisher exact test). The features with the greatest individual sensitivity and specificity, respectively, in the diagnosis of BA were triangular cord sign (73% and 100%), abnormal gallbladder wall (91% and 95%) and shape (70% and 100%), and an absent common bile duct (93% and 92%). The hepatic artery diameter was significantly larger in infants with BA than in those without BA (mean+/-standard deviation, 2.2 mm+/-0.59 vs 1.6 mm+/-0.40, P<.001), but portal vein diameters were not significantly different. By means of all these US features, 88 of 90 infants were correctly classified as having or not having BA, for an overall accuracy of 98%.
  
  
  CONCLUSIONS
  BA can be distinguished with US from other causes of conjugated hyperbilirubinemia in 98% of infants if multiple US features are carefully evaluated.
authors: Department of Radiology and Children's Liver & GI Unit, St James's University Hospital, Beckett Street, Leeds LS9 7TF, England. teresa.humphrey@leedsth.nhs.uk
authors: Terry M
authors: TM
authors: Humphrey
authors: Mark D
authors: MD
authors: Stringer
mesh_terms: D001656:Biliary Atresia / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography