title: Iterative reconstruction and individualized automatic tube current selection reduce radiation dose while maintaining image quality in 320-multidetector computed tomography coronary angiography.
abstract: OBJECTIVE
  To assess the effect of two iterative reconstruction algorithms (AIDR and AIDR3D) and individualized automatic tube current selection on radiation dose and image quality in computed tomography coronary angiography (CTCA).
  
  
  METHODS
  In a single-centre cohort study, 942 patients underwent electrocardiogram-gated CTCA using a 320-multidetector CT system. Images from group 1 (n = 228) were reconstructed with a filtered back projection algorithm (Quantum Denoising Software, QDS+). Iterative reconstruction was used for group 2 (AIDR, n = 379) and group 3 (AIDR3D, n = 335). Tube current was selected based on body mass index (BMI) for groups 1 and 2, and selected automatically based on scout image attenuation for group 3. Subjective image quality was graded on a four-point scale (1 = excellent, 4 = non-diagnostic).
  
  
  RESULTS
  There were no differences in age (p = 0.975), body mass index (p = 0.435), or heart rate (p = 0.746) between the groups. Image quality improved with iterative reconstruction and automatic tube current selection [1.3 (95% confidence intervals (CI): 1.2-1.4), 1.2 (1.1-1.2) and 1.1 (1-1.2) respectively; p < 0.001] and radiation dose decreased [274 (260-290), 242 (230-253) and 168 (156-180) mGy cm, respectively; p < 0.001].
  
  
  CONCLUSIONS
  The application of the latest iterative reconstruction algorithm and individualized automatic tube current selection can substantially reduce radiation dose whilst improving image quality in CTCA.
authors.affiliation: University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, Edinburgh, UK. Electronic address: michelle.williams@ed.ac.uk.
authors.forename: M C
authors.initials: MC
authors.lastname: Williams
authors.forename: N W
authors.initials: NW
authors.lastname: Weir
authors.forename: S
authors.initials: S
authors.lastname: Mirsadraee
authors.forename: F
authors.initials: F
authors.lastname: Millar
authors.forename: A
authors.initials: A
authors.lastname: Baird
authors.forename: F
authors.initials: F
authors.lastname: Minns
authors.forename: N G
authors.initials: NG
authors.lastname: Uren
authors.forename: G
authors.initials: G
authors.lastname: McKillop
authors.forename: R K
authors.initials: RK
authors.lastname: Bull
authors.forename: E J R
authors.initials: EJ
authors.lastname: van Beek
authors.forename: J H
authors.initials: JH
authors.lastname: Reid
authors.forename: D E
authors.initials: DE
authors.lastname: Newby
mesh_terms: D000465:Algorithms; D015331:Cohort Studies; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007479:Iopamidol / Q000031:analogs & derivatives; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography / Q000379:methods*; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods
chemical_list: D003287:Contrast Media; C057937:iomeprol; D007479:Iopamidol