title: Optimization of coronary attenuation in coronary computed tomography angiography using diluted contrast material.
abstract: BACKGROUND
  The purpose of this study was to evaluate a personalized protocol with diluted contrast material (CM) for coronary computed tomography angiography (CTA).
  
  
  RESULTS
  One hundred patients with suspected coronary artery disease underwent retrospective electrocardiogram-gated coronary CTA on a 256-slice multidetector-row CT scanner. In the diluted CM protocol (n=50), the optimal scan timing and CM dilution rate were determined by the timing bolus scan, with 20% CM dilution (5ml/s during 10s) being considered suitable to achieve the target arterial attenuation of 350 Hounsfield units (HU). In the body weight (BW)-adjusted protocol (n=50, 222mg iodine/kg), only the optimal scan timing was determined by the timing bolus scan. The injection rate and volume in the timing bolus scan and real scan were identical between the 2 protocols. We compared the means and variations in coronary attenuation between the 2 protocols. Coronary attenuation (mean±SD) in the diluted CM and BW-adjusted protocols was 346.1±23.9 HU and 298.8±45.2 HU, respectively. The diluted CM protocol provided significantly higher coronary attenuation and lower variance than did the BW-adjusted protocol (P<0.05, in each).
  
  
  CONCLUSIONS
  The diluted CM protocol facilitates more uniform attenuation on coronary CTA in comparison with the BW-adjusted protocol.
authors.affiliation: Department of Radiology, Ehime University Graduate School of Medicine.
authors.forename: Naoto
authors.initials: N
authors.lastname: Kawaguchi
authors.forename: Akira
authors.initials: A
authors.lastname: Kurata
authors.forename: Teruhito
authors.initials: T
authors.lastname: Kido
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Nishiyama
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kido
authors.forename: Masao
authors.initials: M
authors.lastname: Miyagawa
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Ogimoto
authors.forename: Teruhito
authors.initials: T
authors.lastname: Mochizuki
mesh_terms: D000368:Aged; D001835:Body Weight; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media