title: Intraductal ultrasonography in the diagnosis of bile duct stones: when and whom?
abstract: OBJECTIVE
  Biliary intraductal ultrasonography (IDUS) is highly sensitive in visualizing bile duct stones (BDS). Indications for IDUS, however, in cases of suspected BDS have not yet been established. The aim of the present study was to elucidate adequate indications for IDUS in cases that undergo endoscopic retrograde cholangiopancreatography (ERCP) due to suspected BDS.
  
  
  METHODS
  A total of 213 patients who were suspected of having BDS were included in this retrospective study. The patients were divided into two groups: Group A in which BDS was visualized by ERCP; and Group B in which BDS was demonstrated only by IDUS. Comparison between the groups was carried out.
  
  
  RESULTS
  ERCP successfully visualized BDS in 166 patients. Forty-seven patients underwent IDUS, which revealed BDS and biliary sludge in 12 and eight patients, respectively. The diameter of the largest stone was 13 ± 6 mm in Group A and 5 ± 1 mm in Group B (P < 0.001). The sensitivity, specificity, and accuracy of ERCP in the diagnosis of BDS were 93%, 100%, and 94%, respectively. The sensitivity was influenced by the size of BDS: 100% in cases of stones ≥ 8 mm in size, but 74% in those with stones < 8 mm. In cases with stones < 8 mm, the sensitivity was significantly affected by the bile duct diameter (≥ 12 mm vs < 12 mm, P < 0.05).
  
  
  CONCLUSIONS
  When ERCP fails to visualize stones in patients with suspected BDS, IDUS is recommended, especially in those with a bile duct ≥ 12 mm in diameter.
authors.affiliation: Department of Gastroenterology, Sendai City Medical Center, Sendai, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Endo
authors.forename: Kei
authors.initials: K
authors.lastname: Ito
authors.forename: Naotaka
authors.initials: N
authors.lastname: Fujita
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Noda
authors.forename: Go
authors.initials: G
authors.lastname: Kobayashi
authors.forename: Takashi
authors.initials: T
authors.lastname: Obana
authors.forename: Jun
authors.initials: J
authors.lastname: Horaguchi
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Koshita
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Kanno
authors.forename: Takahisa
authors.initials: T
authors.lastname: Ogawa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002760:Cholangiopancreatography, Endoscopic Retrograde; D019160:Endosonography; D005260:Female; D042882:Gallstones / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016717:Sphincterotomy, Endoscopic