title: Multiphase contrast medium injection for optimization of computed tomographic coronary angiography.
abstract: OBJECTIVE
  Electron beam angiography is a minimally invasive imaging technique. Adequate vascular opacification throughout the study remains a critical issue for image quality. We hypothesized that vascular image opacification and uniformity of vascular enhancement between slices can be improved using multiphase contrast medium injection protocols.
  
  
  METHODS
  We enrolled 244 consecutive patients who were randomized to three different injection protocols: single-phase contrast medium injection (Group 1), dual-phase contrast medium injection with each phase at a different injection rate (Group 2), and a three-phase injection with two phases of contrast medium injection followed by a saline injection phase (Group 3). Parameters measured were aortic opacification based on Hounsfield units and uniformity of aortic enhancement at predetermined slices (locations from top [level 1] to base [level 60]).
  
  
  RESULTS
  In Group 1, contrast opacification differed across seven predetermined locations (scan levels: 1st versus 60th, P < .05), demonstrating significant nonuniformity. In Group 2, there was more uniform vascular enhancement, with no significant differences between the first 50 slices (P > .05). In Group 3, there was greater uniformity of vascular enhancement and higher mean Hounsfield units value across all 60 images, from the aortic root to the base of the heart (P < .05).
  
  
  CONCLUSIONS
  The three-phase injection protocol improved vascular opacification at the base of the heart, as well as uniformity of arterial enhancement throughout the study.
authors.affiliation: Division of Cardiology, Los Angeles Biomedical Research Institute at Harbor-UCLA, Torrance, CA 90502, USA. mbudoff@labiomed.org
authors.forename: Matthew Jay
authors.initials: MJ
authors.lastname: Budoff
authors.forename: Jerold S
authors.initials: JS
authors.lastname: Shinbane
authors.forename: Janis
authors.initials: J
authors.lastname: Child
authors.forename: Sivi
authors.initials: S
authors.lastname: Carson
authors.forename: Alex
authors.initials: A
authors.lastname: Chau
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Liu
authors.forename: SongShou
authors.initials: S
authors.lastname: Mao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001018:Aortic Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003326:Coronary Circulation / Q000187:drug effects; D005260:Female; D006801:Humans; D007269:Injections, Intra-Arterial; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media