title: Improved image quality at 256-slice coronary CT angiography in patients with a high heart rate and coronary artery disease: comparison with 64-slice CT imaging.
abstract: BACKGROUND
  The 256-slice computed tomography (CT) scanners with wider detector coverage and faster gantry rotation speed are now available. The performance of scanners that feature a rotation speed of 270 ms at coronary CT angiography (CCTA) has not been evaluated in patients with a higher heart rate.
  
  
  OBJECTIVE
  To evaluate the image quality of 256-slice CT with faster gantry rotation speed in patients undergoing CCTA.
  
  
  METHODS
  We enrolled 886 patients; 357(40.3%) underwent study on a 64-slice CT at a rotation speed of 420 ms, the other 529 (59.7%) were examined using a 256-slice CT scanner at 270 ms. Two observers judged the image quality of 2658 imaged coronary arteries on a 4-point scale.
  
  
  RESULTS
  The mean image quality score was significantly higher for the 256 - than the 64-slice CT scans (3.94 ± 0.28 vs. 3.73 ± 0.61; P < 0.01). There was no significant difference in the image quality scores between 64 - and 256-slice scans in patients whose heart rate (HR) was <60 bpm. However, in patients whose HR exceeded 60 bpm these scores were significantly higher for 256-slice CT images (P < 0.01).
  
  
  CONCLUSIONS
  CCTA performed on the 256-slice CT scanner yielded significantly better image quality in patients with an HR exceeding 60 bpm.
authors.affiliation: Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan seisei0430@nifty.com.
authors.forename: Seitaro
authors.initials: S
authors.lastname: Oda
authors.affiliation: Department of Diagnostic Radiology, Kumamoto Chuo Hospital, Kumamoto, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Katahira
authors.affiliation: Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Utsunomiya
authors.affiliation: Department of Diagnostic Radiology, Kumamoto Chuo Hospital, Kumamoto, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Takaoka
authors.affiliation: Department of Diagnostic Radiology, Kumamoto Chuo Hospital, Kumamoto, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Honda
authors.affiliation: Department of Cardiology, Kumamoto Chuo Hospital, Kumamoto, Japan.
authors.forename: Katsuo
authors.initials: K
authors.lastname: Noda
authors.affiliation: Department of Cardiology, Kumamoto Chuo Hospital, Kumamoto, Japan.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Oshima
authors.affiliation: Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yuki
authors.affiliation: Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Namimoto
authors.affiliation: Department of Diagnostic Radiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Yamashita
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D000319:Adrenergic beta-Antagonists
keywords: 256-slice CT; Coronary CT angiography; computed tomography (CT); heart rate; image quality; rotation speed