title: Diagnostic quality of dual-source coronary CT examinations performed without heart rate control: importance of obesity and heart rate on image quality.
abstract: OBJECTIVE
  For dual-source cardiac computed tomography (CT) scans without heart rate (HR) control, the influence of body habitus on quality is uncertain. We evaluated study quality across a range of HRs and body size.
  
  
  METHODS
  One hundred sixty subjects were randomly selected for 4 HR groups (<70, 70-79, 80-89, ≥90 beats per minute) from 703 subjects who underwent cardiac CT without premedication. Coronary visualization quality was scored on a 3-point scale (1, nondiagnostic; 2, diagnostic; 3, excellent).
  
  
  RESULTS
  Ninety-nine percent of coronaries were diagnostic quality. Six vessels were nondiagnostic, mostly due to motion. Nondiagnostic or diagnostic scores (<3) were greatest in the group with HR of more than or equal to 90 beats per minute. All normal weight subjects had excellent quality, but 6% of vessels in overweight and 17% in obese subjects had diagnostic scores less than 3. The mean effective dose was 11.4 mSv and correlated with body size.
  
  
  CONCLUSIONS
  Diagnostic quality cardiac CT examinations can be obtained without premedication regardless of body size.
authors.affiliation: From the *Department of Radiology, and †Johns Hopkins GeneSTAR Research Program, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.
authors.forename: Stefan L
authors.initials: SL
authors.lastname: Zimmerman
authors.forename: Brian G
authors.initials: BG
authors.lastname: Kral
authors.forename: Elliot K
authors.initials: EK
authors.lastname: Fishman
mesh_terms: D017023:Coronary Angiography / Q000379:methods* / Q000592:standards*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed