title: Coronary CT angiography with single-source and dual-source CT: comparison of image quality and radiation dose between prospective ECG-triggered and retrospective ECG-gated protocols.
abstract: BACKGROUND
  This study is conducted to investigate and compare image quality and radiation dose between prospective ECG-triggered and retrospective ECG-gated coronary CT angiography (CCTA) with the use of single-source CT (SSCT) and dual-source CT (DSCT).
  
  
  METHODS
  A total of 209 patients who underwent CCTA with suspected coronary artery disease scanned with SSCT (n=95) and DSCT (n=114) scanners using prospective ECG-triggered and retrospective ECG-gated protocols were recruited from two institutions. The image was assessed by two experienced observers, while quantitative assessment was performed by measuring the image noise, the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR). Effective dose was calculated using the latest published conversion coefficient factor.
  
  
  RESULTS
  A total of 2087 out of 2880 coronary artery segments were assessable, with 98.0% classified as of sufficient and 2.0% as of insufficient image quality for clinical diagnosis. There was no significant difference in overall image quality between prospective ECG-triggered and retrospective gated protocols, whether it was performed with DSCT or SSCT scanners. Prospective ECG-triggered protocol was compared in terms of radiation dose calculation between DSCT (6.5 ± 2.9 mSv) and SSCT (6.2 ± 1.0 mSv) scanners and no significant difference was noted (p=0.99). However, the effective dose was significantly lower with DSCT (18.2 ± 8.3 mSv) than with SSCT (28.3 ± 7.0 mSv) in the retrospective gated protocol.
  
  
  CONCLUSIONS
  Prospective ECG-triggered CCTA reduces radiation dose significantly compared to retrospective ECG-gated CCTA, while maintaining good image quality.
authors.affiliation: Discipline of Medical Imaging, Department of Imaging and Applied Physics, Curtin University, GPO Box U1987, Perth, Western Australia 6845, Australia; Diagnostic Imaging & Radiotherapy Programme, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia.
authors.forename: Akmal
authors.initials: A
authors.lastname: Sabarudin
authors.forename: Zhonghua
authors.initials: Z
authors.lastname: Sun
authors.forename: Ahmad Khairuddin Md
authors.initials: AK
authors.lastname: Yusof
mesh_terms: D000328:Adult; D000368:Aged; D017023:Coronary Angiography / Q000379:methods / Q000592:standards*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D004562:Electrocardiography / Q000379:methods / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011829:Radiation Dosage; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000592:standards*
keywords: Dual-source CT; Image quality; Prospective ECG triggering; Radiation dose; Retrospective ECG gating; Single-source CT