title: 128-slice dual-source CT coronary angiography with prospectively electrocardiography-triggered high-pitch spiral mode: radiation dose, image quality, and diagnostic acceptability.
abstract: BACKGROUND
  Dual-source computed tomography (CT) enables CT coronary angiography (CTCA) with a prospectively electrocardiography (ECG)-triggered high-pitch spiral (HPS) mode.
  
  
  OBJECTIVE
  To evaluate the radiation dose, image quality, and diagnostic acceptability of the HPS mode in CTCA and to compare HPS with the step-and-shoot (SAS) and low-pitch spiral (LPS) modes.
  
  
  METHODS
  One hundred and thirty-eight patients who underwent CTCA with a 128-slice dual-source CT scanner were retrospectively included in this study. Seventeen patients (average heart rate of ≤65 beats per minute [bpm] prior to acquisition) were evaluated in the HPS mode, 88 (average heart rate of >65 and ≤80 bpm prior to acquisition) in the SAS mode, and 33 (average heart rate of >80 bpm prior to acquisition or patients with an unstable heart rhythm) in the LPS mode. Radiation dose and image noise were recorded for each patient. Diagnostic acceptability was graded using a four-point scale (1, unacceptable; 2, suboptimal; 3, acceptable; 4, fully acceptable).
  
  
  RESULTS
  The effective dose in the HPS mode was 1.5 ± 0.2 mSv, which was lower than that in SAS (8.9 ± 2.7 mSv) and LPS (21.5 ± 4.3 mSv) modes. There were no significant differences in the image noise levels in the descending aorta and left atrium. The average per-patient diagnostic acceptability was 3.2, 3.6, and 3.7 in HPS, SAS, and LPS modes, respectively.
  
  
  CONCLUSIONS
  The radiation dose is lower with HPS than with other modes, and the HPS mode-acquired images of patients with heart rates of ≤65 bpm are nearly acceptable for diagnostic image interpretation.
authors.affiliation: Department of Quantum Medical Technology, Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan matsuk@mhs.mp.kanazawa-u.ac.jp.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Matsubara
authors.affiliation: Department of Radiological Technology, Kanazawa University Hospital, Kanazawa, Ishikawa Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Sakuda
authors.affiliation: Department of Radiological Technology, Kanazawa University Hospital, Kanazawa, Ishikawa Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Nunome
authors.affiliation: Department of Radiological Technology, Kanazawa University Hospital, Kanazawa, Ishikawa Japan.
authors.forename: Tadanori
authors.initials: T
authors.lastname: Takata
authors.affiliation: Department of Quantum Medical Technology, Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan.
authors.forename: Kichiro
authors.initials: K
authors.lastname: Koshida
authors.affiliation: Department of Radiology, Faculty of Medicine, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Ishikawa Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Gabata
mesh_terms: D000368:Aged; D055424:Cardiac-Gated Imaging Techniques; D017023:Coronary Angiography / Q000379:methods*; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D005260:Female; D006339:Heart Rate; 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*
keywords: CT angiography; adults; cardiac; comparative studies; dosimetry