title: Which concentration to choose in dual flow cardiac CT?: dual flow cardiac CT.
abstract: OBJECTIVE
  An extensive number of protocols have been suggested to allow for functional diagnostics; however, no data is available about the minimal amount of contrast medium to achieve reliable imaging properties. None of the plethora of existing studies report a rational why the specific concentration was chosen.
  
  
  METHODS
  A total of 40 patients were included in this prospective, controlled study. They were divided up into four equal groups getting a different concentration (10%, 20%, 30% or 40%) of a second contrast medium bolus. Corresponding septal and right ventricular ROIs were compared. A visual score was established. Coronary attenuation was measured in the right and left coronary artery. Streak artifacts in the right atrium/ventricle were assessed.
  
  
  RESULTS
  In the 10% contrast medium (CM) group only in 5/10 (50%) patients full septal delineation was reached. In all other groups full septal visualization was obtained. No group showed a relevant difference of mean density measured in HU units of the left ventricle or the coronary arteries. All study groups except of group 1 (10% CM) showed streak artifacts in the right atrium.
  
  
  CONCLUSIONS
  The dual flow protocol with a minimum concentration of 20% improves septal visualization as basis for left ventricular functional assessment, however, does not allow for reliable right ventricular or atrial visualization. There is no significant difference between the different concentration protocols in terms of coronary attenuation.
authors.affiliation: Radiological Institute, Friedrich-Alexander-University-Erlangen-Nuremberg, Germany. wolfgang.wuest@uk-erlangen.de
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wuest
authors.forename: Katharina
authors.initials: K
authors.lastname: Anders
authors.forename: Michael
authors.initials: M
authors.lastname: Scharf
authors.forename: Matthias
authors.initials: M
authors.lastname: May
authors.forename: Michael
authors.initials: M
authors.lastname: Brand
authors.forename: Michael
authors.initials: M
authors.lastname: Uder
authors.forename: Dieter
authors.initials: D
authors.lastname: Ropers
authors.forename: Stephan
authors.initials: S
authors.lastname: Achenbach
authors.forename: Axel
authors.initials: A
authors.lastname: Kuettner
mesh_terms: D000465:Algorithms; D003287:Contrast Media / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D055414:Myocardial Perfusion Imaging / Q000379:methods*; 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*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*
chemical_list: D003287:Contrast Media