title: Pseudo gallbladder sign in biliary atresia--an imaging pitfall.
abstract: BACKGROUND
  Ultrasound (US) is used to identify causes of neonatal cholestasis. We describe a potential sonographic pitfall, the "pseudo gallbladder," in biliary atresia (BA).
  
  
  OBJECTIVE
  To describe the Pseudo Gallbladder sign (PsGB sign).
  
  
  METHODS
  Sonograms/clinical records of 20 confirmed BA infants and 20 non-BA cases were reviewed retrospectively. For the BA group, preoperative sonography and surgical and pathological findings were examined. For the non-BA group, sonographic features and pathological findings were examined. The PsGB sign is defined as a fluid-filled structure, located in the expected region of the gallbladder, measuring ≤ 15 mm in length but without a well-defined or normal-appearing gallbladder wall.
  
  
  RESULTS
  A recognizable gallbladder and normal gallbladder wall were present in all non-BA infants. However, none of the BA infants had a sonographically normal gallbladder. Seventy-three percent of BA patients had a PsGB, and in 27% no gallbladder or gallbladder-like structure was detected.
  
  
  CONCLUSIONS
  A gallbladder-like structure in BA is common and can be misinterpreted as a normal gallbladder, delaying diagnosis and therapy. Recognition of this imaging pitfall, described here as the pseudo gallbladder sign, will help avoid this error.
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94143-0628, USA. seerat.aziz@ucsf.edu
authors.forename: Seerat
authors.initials: S
authors.lastname: Aziz
authors.forename: Yvette
authors.initials: Y
authors.lastname: Wild
authors.forename: Philip
authors.initials: P
authors.lastname: Rosenthal
authors.forename: Ruth B
authors.initials: RB
authors.lastname: Goldstein
mesh_terms: D001656:Biliary Atresia / Q000000981:diagnostic imaging*; D002779:Cholestasis / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D005260:Female; D005704:Gallbladder / Q000000981:diagnostic imaging*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012189:Retrospective Studies; D014463:Ultrasonography