title: Reducing Iodine Contrast Volume in CT Angiography of the Abdominal Aorta Using Integrated Tube Potential Selection and Weight-Based Method Without Compromising Image Quality.
abstract: OBJECTIVE
  The purpose of this study is to determine whether image quality was maintained when a weight-based protocol incorporating tube potential selection was used to select lower iodine contrast volumes for aortic CT angiography (CTA).
  
  
  METHODS
  Patients with potentially decreased renal function underwent CTA performed with the iodinated contrast volume determined using a table incorporating different tube potentials and patient weights. The image quality of CTA examinations performed with a reduced iodine volume (hereafter known as "low-iodine CTA examinations"), internal control CTA examinations (i.e., prior examinations), and size-matched control CTA examinations was evaluated in separate reading sessions conducted by three vascular radiologists who were blinded as to the contrast volume and tube potential used. Side-by-side unblinded comparison of the examinations was also performed. Aortic attenuation and the contrast-to-noise ratio were measured. Comparisons were performed using the Wilcoxon signed rank test.
  
  
  RESULTS
  Fifty low-iodine CTA examinations, 36 internal control CTA examinations, and 50 size-matched control CTA examinations were performed. Contrast volumes were 63% lower when the protocol based on tube potential and patient weight was used (mean contrast volume, 49 mL for low-iodine CTA vs 133 mL for internal control CTA and 138 mL for size-matched control CTA). The mean volume CT dose index was 15.1 mGy for low-iodine CTA versus 18.8 mGy for internal control CTA (p < 0.001), and 15.3 mGy for low-iodine CTA versus 17.1 mGy for size-matched control CTA (p = 0.11). Of the image quality and diagnostic confidence evaluations for low-iodine CTA examinations, over 97% had acceptable image quality and diagnostic confidence for blinded (50/50) and unblinded (35/36) comparisons. Aortic attenuation was similar between groups (p = 0.13-0.71).
  
  
  CONCLUSIONS
  A weight-based protocol that incorporates tube potential selection allows the use of substantially lower volumes of iodinated contrast material in aortic CTA while maintaining acceptable image quality.
authors.affiliation: 1 Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905.
authors.forename: Rogerio
authors.initials: R
authors.lastname: Vasconcelos
authors.affiliation: 1 Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905.
authors.forename: Terri J
authors.initials: TJ
authors.lastname: Vrtiska
authors.affiliation: 1 Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Foley
authors.affiliation: 1 Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905.
authors.forename: Thanila A
authors.initials: TA
authors.lastname: Macedo
authors.affiliation: 1 Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905.
authors.forename: Juan C Montoya
authors.initials: JC
authors.lastname: Cardona
authors.affiliation: 1 Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905.
authors.forename: Eric E
authors.initials: EE
authors.lastname: Williamson
authors.affiliation: 1 Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905.
authors.forename: Cynthia H
authors.initials: CH
authors.lastname: McCollough
authors.affiliation: 1 Department of Radiology, Mayo Clinic, 200 First St SW, Rochester, MN 55905.
authors.forename: Joel G
authors.initials: JG
authors.lastname: Fletcher
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D001018:Aortic Diseases / Q000000981:diagnostic imaging*; D001027:Aortography / Q000379:methods*; D000072226:Computed Tomography Angiography / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007455:Iodine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011856:Radiographic Image Enhancement / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018511:Systems Integration; D055815:Young Adult
chemical_list: D003287:Contrast Media; D007455:Iodine
keywords: CT angiography; iodinated contrast; nephrotoxicity; tube potential