title: Emergency biliary sonography: utility of common bile duct measurement in the diagnosis of cholecystitis and choledocholithiasis.
abstract: BACKGROUND
  Measurement of the common bile duct (CBD) has traditionally been considered an integral part of gallbladder sonography, but accurate identification of the CBD can be difficult for novice sonographers.
  
  
  OBJECTIVE
  To determine the prevalence of isolated sonographic CBD dilation in emergency department (ED) patients with cholecystitis or choledocholithiasis without laboratory abnormalities or other pathologic findings on biliary ultrasound.
  
  
  METHODS
  We conducted a retrospective chart review on two separate ED patient cohorts between June 2000 and June 2010. The first cohort comprised all ED patients undergoing a biliary ultrasound and subsequent cholecystectomy for presumed cholecystitis. The second cohort consisted of all ED patients receiving a biliary ultrasound who were ultimately diagnosed with choledocholithiasis. Ultrasound data and contemporaneous laboratory values were collected. Postoperative gallbladder pathology reports and endoscopic retrograde cholangiopancreatography (ERCP) reports were used as the criterion standard for final diagnosis.
  
  
  RESULTS
  Of 666 cases of cholecystitis, there were 251 (37.7%) with a dilated CBD > 6 mm and only 2 cases (0.3%; 95% confidence interval [CI] 0.0-0.7%) of isolated CBD dilation with an otherwise negative ultrasound and normal laboratory values. Of 111 cases of choledocholithiasis, there were 80 (72.0%) with a dilated CBD and only 1 case (0.9%; 95% CI 0.0-2.7%) with an otherwise negative ultrasound and normal laboratory values.
  
  
  CONCLUSIONS
  The prevalence of isolated sonographic CBD dilation in cholecystitis and choledocholithiasis is <1%. Omission of CBD measurement is unlikely to result in missed cholecystitis or choledocholithiasis in the setting of a routine ED evaluation with an otherwise normal ultrasound and normal laboratory values.
authors.affiliation: Department of Emergency Medicine, York Hospital (Wellspan Health), York, Pennsylvania.
authors.forename: Brent A
authors.initials: BA
authors.lastname: Becker
authors.affiliation: Department of Emergency Medicine, San Antonio Uniformed Service Health Education Consortium, San Antonio Military Medical Center, Fort Sam Houston, Texas.
authors.forename: Eric
authors.initials: E
authors.lastname: Chin
authors.affiliation: Department of Emergency Medicine, University of California, Irvine, Orange, California.
authors.forename: Eric
authors.initials: E
authors.lastname: Mervis
authors.affiliation: Department of Emergency Medicine, University of California, Irvine, Orange, California.
authors.forename: Craig L
authors.initials: CL
authors.lastname: Anderson
authors.affiliation: Department of Emergency Medicine, Kaiser Permanente South Sacramento, Sacramento, California.
authors.forename: Masaru H
authors.initials: MH
authors.lastname: Oshita
authors.affiliation: Department of Emergency Medicine, University of California, Irvine, Orange, California.
authors.forename: J Christian
authors.initials: JC
authors.lastname: Fox
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002760:Cholangiopancreatography, Endoscopic Retrograde; D002763:Cholecystectomy; D002764:Cholecystitis / Q000000981:diagnostic imaging* / Q000601:surgery; D042883:Choledocholithiasis / Q000000981:diagnostic imaging*; D003135:Common Bile Duct / Q000000981:diagnostic imaging* / Q000473:pathology; D004108:Dilatation, Pathologic / Q000000981:diagnostic imaging; D004636:Emergency Service, Hospital; D005260:Female; D005704:Gallbladder / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014463:Ultrasonography; D055815:Young Adult
keywords: biliary tract diseases; cholecystitis; choledocholithiasis; common bile duct; emergency department; gallbladder; ultrasonography