COMPARISON OF DIAGNOSTIC-ACCURACY WITH CARBON-DIOXIDE VERSUS IODINATED CONTRAST MATERIAL IN THE IMAGING OF HEMODIALYSIS ACCESS FISTULAS

PURPOSE: 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. PATIENTS AND METHODS: Thirty-two patients underwent digital subtraction imaging of the fistulas performed with both iodinated contrast material and C O2 to evaluate the venous anastomosis. The images were blinded and the degree of stenosis was graded in 10% increments by two physicians. St atistical analysis including sensitivity, specificity, and accuracy of CO2 images was performed. RESULTS: There was no significant differenc e in physician ratings of the degree of venous stenosis (P > .30). Est imation of the degree of stenosis was significantly higher with CO2 th an with ionic contrast material (P = .0001). When iodinated contrast m aterial is used as the gold standard, the sensitivity, specificity, an d accuracy of CO2 were 94%, 58%, and 75%, respectively. CONCLUSIONS: C O2 has a role as a contrast agent in the imaging of dialysis access gr afts when the use of iodinated contrast material is of concern. CO2 is safe for venous injections; however, it should not be used to evaluat e the arterial anastomosis with the ''reflux technique.''