title: Adaptation of contrast injection protocol to tube potential for cardiovascular CT.
abstract: OBJECTIVE
  The purpose of this study was to investigate and validate adaptation of a cardiovascular CT angiography contrast injection protocol for lower tube potential.
  
  
  METHODS
  Eighty-three patients evaluated for thoracic aortic disease with a 256-MDCT scanner were imaged at 120 kV (group 1) or 100 kV (group 2) with the same contrast protocol (90 mL iopromide 370 mg I/mL at 3.5 mL/s). A pharmacokinetic model was validated and used to simulate aortic attenuation in group 2 patients with 20%, 33%, and 44% reduction in contrast volume. A 44% volume reduction was applied to 50 additional patients who underwent imaging at 100 kV (group 3). Patient characteristics, scanning and radiation parameters, and objective and subjective image indexes were compared among groups.
  
  
  RESULTS
  Group 2 patients had higher mean aortic blood attenuation (399±61 HU) than group 1 patients (281±48 HU) (p<0.001) but similar image noise. Group 3 and group 1 patients had similar mean aortic attenuation and noise. Subjective assessment of image quality indicated that group 3 and group 1 had comparable percentages of images with good or excellent diagnostic confidence scores (reader 1, 98% vs 96%; reader 2, 96% vs 96%).
  
  
  CONCLUSIONS
  Lower tube potential (100 kV) for cardiothoracic CT could be accompanied by a 44% reduction in contrast volume with satisfactory aortic blood-pool attenuation in most patients. More personalized adaptation of the contrast protocol that takes into account patient characteristics and tube potential is necessary to ensure sufficient contrast enhancement for all patients.
authors.affiliation: 1 Informatics Research and Strategy, Radiology and Interventional, Bayer HealthCare Medical Care, Indianola, PA.
authors.forename: Yajuan
authors.initials: Y
authors.lastname: Wang
authors.forename: Michael
authors.initials: M
authors.lastname: Bolen
authors.forename: Gregg
authors.initials: G
authors.lastname: Sydow
authors.forename: Anjali
authors.initials: A
authors.lastname: Kottha
authors.forename: Kassem
authors.initials: K
authors.lastname: Soufan
authors.forename: Jennifer
authors.initials: J
authors.lastname: Bullen
authors.forename: Corey
authors.initials: C
authors.lastname: Kemper
authors.forename: John
authors.initials: J
authors.lastname: Kalafut
authors.forename: Sandra S
authors.initials: SS
authors.lastname: Halliburton
mesh_terms: D001018:Aortic Diseases / Q000000981:diagnostic imaging* / Q000378:metabolism; D003198:Computer Simulation; D003287:Contrast Media / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007472:Iohexol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide
keywords: cardiovascular CT; contrast dose; contrast injection protocol; radiation dose; tube potential