title: Comparison of diagnostic accuracy with carbon dioxide versus iodinated contrast material in the imaging of hemodialysis access fistulas.
abstract: OBJECTIVE
  Imaging of dialysis fistulas was performed with use of carbon dioxide and iodinated contrast material. Images were then compared to assess the quality and accuracy of CO2 as a contrast agent.
  
  
  METHODS
  Thirty-two patients underwent digital subtraction imaging of the fistulas performed with both iodinated contrast material and CO2 to evaluate the venous anastomosis. The images were blinded and the degree of stenosis was graded in 10% increments by two physicians. Statistical analysis including sensitivity, specificity, and accuracy of CO2 images was performed.
  
  
  RESULTS
  There was no significant difference in physician ratings of the degree of venous stenosis (P > .30). Estimation of the degree of stenosis was significantly higher with CO2 than with ionic contrast material (P = .0001). When iodinated contrast material is used as the gold standard, the sensitivity, specificity, and accuracy of CO2 were 94%, 58%, and 75%, respectively.
  
  
  CONCLUSIONS
  CO2 has a role as a contrast agent in the imaging of dialysis access grafts when the use of iodinated contrast material is of concern. CO2 is safe for venous injections; however, it should not be used to evaluate the arterial anastomosis with the "reflux technique."
authors.affiliation: Department of Cardiovascular, Methodist Hospital of Indiana, Indianapolis 46206.
authors.forename: K O
authors.initials: KO
authors.lastname: Ehrman
authors.forename: T E
authors.initials: TE
authors.lastname: Taber
authors.forename: G M
authors.initials: GM
authors.lastname: Gaylord
authors.forename: P B
authors.initials: PB
authors.lastname: Brown
authors.forename: J P
authors.initials: JP
authors.lastname: Hage
mesh_terms: D015901:Angiography, Digital Subtraction / Q000379:methods*; D001166:Arteriovenous Shunt, Surgical; D001807:Blood Vessel Prosthesis; D002245:Carbon Dioxide; D005069:Evaluation Studies as Topic; D005260:Female; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging*; D006801:Humans; D007479:Iopamidol; D008297:Male; D008875:Middle Aged; D011138:Polytetrafluoroethylene; D006435:Renal Dialysis; D012680:Sensitivity and Specificity
chemical_list: D002245:Carbon Dioxide; D011138:Polytetrafluoroethylene; D007479:Iopamidol