title: Difference of CBD width on US vs. ERCP.
abstract: OBJECTIVE
  To investigate the relationship between US and ERCP in the measurement of common bile duct (CBD) width after application of Compound and Harmonic imaging on ultrasound.
  
  
  METHODS
  We prospectively evaluated the CBD width as measured on endoscopic retrograde cholangiopancreatography (ERCP) and ultrasonography (US), applying Compound and Harmonic US techniques, on 100 patients. Furthermore, we retrospectively re-examined US and ERCP images of 48 patients who underwent ERCP and US during the same hospitalization period.
  
  
  RESULTS
  The average difference in measurements by US compared to ERCP was 2.3 mm (P < 0.01) in the retrospective and 1.9 mm in the prospective study (P < 0.001). The average difference in measurements between US and ERCP in post-cholecystectomy patients was 4.0 mm in the retrospective study (10 patients), and 3.8 in the prospective study (25 patients). The difference between the measurements on both examinations decreased with increasing CBD width. There was a good correlation between ERCP and US measurements of CBD width (r = 0.73 for all patients and r = 0.88 for patients with intact gallbladder, P < 0.001).
  
  
  CONCLUSIONS
  There is a gap between measurement of CBD width on US and ERCP of about 2 mm. The application of Compound and Harmonic techniques in the prospective study probably enabled a more accurate sonographic measurement.
authors.affiliation: Department of Diagnostic Imaging, Ultrasound Unit, Rambam Medical Center, POB 9602, Haifa, 31096, Israel. o_brook@rambam.health.gov.il
authors.forename: Olga R
authors.initials: OR
authors.lastname: Brook
authors.forename: Alain
authors.initials: A
authors.lastname: Suissa
authors.forename: Iyad
authors.initials: I
authors.lastname: Khamaysi
authors.forename: Dorit
authors.initials: D
authors.lastname: Koren
authors.forename: Diana
authors.initials: D
authors.lastname: Gaitini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000379:methods*; D003135:Common Bile Duct / Q000033:anatomy & histology* / Q000473:pathology*; D003952:Diagnostic Imaging / Q000592:standards; D019723:Endoscopes; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013997:Time Factors; D014463:Ultrasonography / Q000295:instrumentation / Q000379:methods*