title: Intraductal US is a useful adjunct to ERCP for distinguishing malignant from benign biliary strictures.
abstract: BACKGROUND
  Distinguishing malignant from benign biliary strictures remains a challenge. This prospective study assessed intraductal US as an adjunct to endoscopic retrograde cholangiography and tissue sampling for diagnosis of malignant and benign biliary strictures.
  
  
  METHODS
  Sixty-two patients were enrolled who had biliary strictures suspected to be malignant but with negative tissue sampling by endoscopic retrograde cholangiography, or suspected biliary strictures based on clinical manifestations and/or cross-sectional imaging. Intraductal US was performed with an over-the-wire 2.4-mm diameter 20 MHz catheter US probe. The diagnostic accuracy of endoscopic retrograde cholangiography plus tissue sampling with and without intraductal US was compared with surgical findings or clinical outcome at a 12-month follow-up (benign/malignant) in nonsurgical cases. Tissue sampling results were reported as malignant, suspicious for malignancy, atypical, or normal. Analysis was by intention-to-treat.
  
  
  RESULTS
  Two patients (3%) were excluded from analysis because the stricture could not be traversed with the intraductal US probe. Of the 60 remaining patients (37 men, mean age 64 years, range 27-89 years), 31 had malignant strictures (12 cholangiocarcinoma, 8 pancreatic, 5 metastatic, 3 gallbladder, 3 papilla), and 29 had benign strictures. Sphincterotomy was not required in any case to facilitate intraductal US. Fourteen patients (23%) underwent subsequent surgery including 11 with a preoperative diagnosis of resectable tumor. Endoscopic retrograde cholangiography/tissue sampling (atypia considered equivalent to benign) correctly identified 15 of 31 malignant strictures (p = 0.001) and all 29 benign strictures (p = 0.16) (accuracy 73%, sensitivity 48%, specificity 100%). The addition of intraductal US correctly identified 28 of 31 malignant strictures and 27 of 29 benign strictures (accuracy 92%, sensitivity 90%, specificity 93%). Of 11 patients with tumors who came to surgery, intraductal US correctly staged 4 (36%), understaged 5 (45%), missing metastatic lymph nodes in all cases and vascular invasion in 1 patient, and overstaged 2 (18%), with a false-positive diagnosis of metastatic lymph nodes in 1 and tumor mass in 1 patient who had no cancer at surgery.
  
  
  CONCLUSIONS
  Technically easy, intraductal US is a valuable adjunct to endoscopic retrograde cholangiography/tissue sampling that increases the ability to distinguish malignant from benign strictures. Intraductal US is unsuitable for assessing lymph nodes associated with malignant strictures.
authors.affiliation: Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Farrell
authors.forename: Banke
authors.initials: B
authors.lastname: Agarwal
authors.forename: Steven L
authors.initials: SL
authors.lastname: Brandwein
authors.forename: John
authors.initials: J
authors.lastname: Underhill
authors.forename: Ram
authors.initials: R
authors.lastname: Chuttani
authors.forename: Douglas K
authors.initials: DK
authors.lastname: Pleskow
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001660:Biliary Tract Diseases / Q000000981:diagnostic imaging* / Q000601:surgery; D002760:Cholangiopancreatography, Endoscopic Retrograde; D019160:Endosonography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012680:Sensitivity and Specificity