title: Venous reflux on carotid computed tomography angiography: relationship with left-arm injection.
abstract: OBJECTIVE
  We evaluated the relationship between image degradation due to the reflux of contrast agent into the major neck veins and use of a left-arm injection site during computed tomographic (CT) angiography of the carotid arteries.
  
  
  METHODS
  A total of 364 patients underwent 4-section carotid CT angiography performed with an injection into the right (n = 183) or left (n = 181) arm. We calculated the volume of refluxed contrast medium and measured the retrosternal distance measured as the shortest distance between the sternum and the arch or its branches. Nine patients underwent follow-up CT angiography weeks later by using the side of injection not used before for comparison.
  
  
  RESULTS
  The amount of refluxed contrast medium was greater with left-arm injection than with right-arm injection (P < 0.001). With left-arm injection, the volume was significantly correlated with the retrosternal distance (r = -0.514, P < 0.001), even after we adjusted for age and sex in the linear regression model (P < 0.001). Five of the 9 patients who received injections in both arms had no reflux of contrast medium, whereas 4 patients had obvious reflux after left-arm but not right-arm injection.
  
  
  CONCLUSIONS
  Normal compression of the left brachiocephalic vein due to a developmental decreased retrosternal space may degrade carotid CT angiograms because of reflux of contrast material into the cervical veins. This degradation can be avoided if right-arm injection is used.
authors.affiliation: Department of Radiology, E-Da Hospital, I-Shou University, Kaohsiung County, Taiwan, ROC.
authors.forename: Ying-Chi
authors.initials: YC
authors.lastname: Tseng
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Hsu
authors.forename: Tsong-Hai
authors.initials: TH
authors.lastname: Lee
authors.forename: Chi-Jen
authors.initials: CJ
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001132:Arm / Q000098:blood supply*; D016121:Brachiocephalic Veins; D002339:Carotid Arteries; D002533:Cerebral Angiography / Q000379:methods*; D016009:Chi-Square Distribution; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000098:blood supply*; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D036542:Tomography, Spiral Computed
chemical_list: D003287:Contrast Media