title: Radiation dose in coronary artery angiography with 320-detector row CT and its diagnostic accuracy: comparison with 64-detector row CT.
abstract: OBJECTIVE
  The aim of this study was the comparison of image quality, diagnostic accuracy and radiation dose of ECG-gated volume scan mode of 320-detector row CT with 64-detector row CT.
  
  
  METHODS
  A hundred and twenty patients receiving coronary artery CT angiography (CTA) were divided into two groups. Sixty patients in Group A underwent 64-detector row CTA; for the remainder, Group B, 320-detector row CT was used. Conventional coronary angiography was then performed in all patients. In Group B, patients with a pulse <65 beat/min underwent a prospective ECG-gated volume scan using a 70-80% R-R phase window and 1-beat, whereas a 30-80% R-R phase window, 2-beat CT was performed in patients with a pulse >65 beat/min.
  
  
  RESULTS
  In Group A, 247 vessels and 920 segments were assessed; in Group B, 242 and 906. In 320-detector row CTA, the coronary stenosis diagnosis' specificities were 98%, 96%, and 95% at the segmental, vessel, and patient levels, respectively (98%, 94%, and 92% in 64-detector row CTA); the negative predictive values were 99%, 98%, and 100% (98%, 97%, and 95% in 64-detector row CTA). There was no significant difference in specificity or negative predictive values between the groups. The average effective radiation dose in Group B was lower than in Group A (P<0.001). In Group B, the dose for 48 patients with 70-80% R-R phase window, 1-beat scan, was lower than for the remaining 12 patients (30-80% R-R phase window, 2-beat) (P<0.001).
  
  
  CONCLUSIONS
  The 320-detector CT reduces the radiation exposure by approximately 80% compared with 64-detector CT, with similar diagnostic accuracy and image quality.
authors.affiliation: Department of Radiology, Harbin Medical University, Harbin, China.
authors.forename: T
authors.initials: T
authors.lastname: Zhang
authors.forename: Z
authors.initials: Z
authors.lastname: Luo
authors.forename: D
authors.initials: D
authors.lastname: Wang
authors.forename: D
authors.initials: D
authors.lastname: Han
authors.forename: J
authors.initials: J
authors.lastname: Bai
authors.forename: X
authors.initials: X
authors.lastname: Meng
authors.forename: B
authors.initials: B
authors.lastname: Shen
mesh_terms: D000328:Adult; D000368:Aged; D017023:Coronary Angiography / Q000379:methods* / Q000592:standards; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods* / Q000592:standards; D011829:Radiation Dosage; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors