title: Detectability of choledocholithiasis on CT: The effect of positive intraduodenal enteric contrast on portovenous contrast-enhanced studies.
abstract: OBJECTIVE
  To retrospectively assess the accuracy of intravenous (IV) contrast-enhanced multidetector CT (MDCT) in choledocholithiasis detectability, in the presence and absence of positive intraduodenal contrast.
  
  
  METHODS
  Over a 3-year period, patients in whom endoscopic retrograde cholangiopancreatography (ERCP) was performed within a week from a portovenous (PV)-enhanced abdominal CT were identified. The final cohort consisted of 48 CT studies in which the entire common bile duct (CBD) length was visualized (19 males, 29 females; mean age, 68 years). We identified two groups according to the absence (n = 31) or presence (n = 17) of positive intraduodenal contrast. CT section thickness ranged from 1.25 to 5 mm. Two radiologists, blinded to clinical information and ERCP results, independently evaluated the CT images. Direct CBD stone visualization was assessed according to previously predefined criteria, correlating with original electronic CT reports and using ERCP findings as the reference standard. A third reader retrospectively reviewed all discordant results. The diagnostic performances of both observers and interobserver agreement were calculated for both groups.
  
  
  RESULTS
  77%-88% sensitivity, 50%-71% specificity, and 71%-74% accuracy were obtained in the group without positive intraduodenal contrast, versus 50%-80% sensitivity, 57%-71% specificity, and 59%-71% accuracy in the group with positive intraduodenal contrast. With the exception of the positive predictive value (PPV), all diagnostic performance parameters decreased in the positive intraduodenal contrast group, mostly affecting the negative predictive value (NPV) (71%-78% vs 50%-67%).
  
  
  CONCLUSIONS
  PV-enhanced MDCT has moderate diagnostic performance in choledocholithiasis detection. A trend of decreasing accuracy was noted in the presence of positive intraduodenal contrast.
authors.affiliation: Department of Radiology, King Abdulaziz University Hospital, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: Amr M
authors.initials: AM
authors.lastname: Ajlan
authors.forename: Benoît
authors.initials: B
authors.lastname: Mesurolle
authors.forename: Lawrence
authors.initials: L
authors.lastname: Stein
authors.forename: Ellen
authors.initials: E
authors.lastname: Kao
authors.forename: Giovanni
authors.initials: G
authors.lastname: Artho
authors.forename: Mashael
authors.initials: M
authors.lastname: Al-Rujaib
authors.forename: Caroline
authors.initials: C
authors.lastname: Reinhold
mesh_terms: D061605:Administration, Intravenous; D000368:Aged; D000369:Aged, 80 and over; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000379:methods; D042883:Choledocholithiasis / Q000000981:diagnostic imaging*; D003135:Common Bile Duct / Q000000981:diagnostic imaging; D003287:Contrast Media / Q000008:administration & dosage; D004386:Duodenum / Q000000981:diagnostic imaging; D005260:Female; D042882:Gallstones / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods; D015588:Observer Variation; D011169:Portal Vein / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D062606:Tertiary Care Centers; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D003287:Contrast Media