title: A prospective randomized trial comparing image quality, study interpretability, and radiation dose of narrow acquisition window with widened acquisition window protocols in prospectively ECG-triggered coronary computed tomography angiography.
abstract: BACKGROUND
  Prospectively triggered coronary computed tomography angiography (CTA) is commonly performed with a widened acquisition window to provide flexibility in image reconstruction.
  
  
  OBJECTIVE
  We conducted a randomized controlled trial to determine whether the use of a narrow acquisition window in prospectively triggered coronary CTA would allow lower radiation dose while preserving image quality and interpretability.
  
  
  METHODS
  Prospective 2-center 2- platform randomized trial that evaluated 205 consecutive patients 96 with widened acquisition (WA) and 109 narrow acquisition (NA) referred for coronary CTA in sinus rhythm and heart rate <65 beats/min. Patients scanned with WA had phases reconstructed at 5% intervals, and each phase was assigned an individual study ID. Images were reviewed with individual phase reconstructions interpreted randomly by 2 level 3 readers with a third for consensus. Images were evaluated with a 5-point Likert scale on a per-vessel basis (best score on any phase). Scores were then dichotomized into diagnostic (score 3-5) compared with nondiagnostic (score 1-2). Readers also reported obstructive coronary artery disease on a per-patient basis. Agreement for the diagnosis of obstructive disease and per-artery interpretability was performed. Signal and noise measurements were also performed.
  
  
  RESULTS
  No difference in demographics between groups (P = NS). The signal-to-noise ratio was comparable 12.99 ± 3.4 NA and 12.53 ± 4.13 for the WA (P = 0.45). The median effective dose was 1.78 mSv for NA compared with 3.26 mSv for WA (P < 0.001). Image quality, diagnostic interpretability, interreader agreement, and downstream testing were not significantly different between the 2 groups (P= NS for all).
  
  
  CONCLUSIONS
  Coronary CTA with NA resulted in a 47% lower radiation dose without significant difference in study interpretability or image quality or increased downstream resource use or testing.
authors: Department of Radiology and Department of Medicine, Division of Cardiology, University of British Columbia, Vancouver, BC, Canada. JLeipsic@providencehealth.bc.ca
authors: Jonathon
authors: J
authors: Leipsic
authors: Troy M
authors: TM
authors: LaBounty
authors: Amr M
authors: AM
authors: Ajlan
authors: James P
authors: JP
authors: Earls
authors: E
authors: E
authors: Strovski
authors: Mark
authors: M
authors: Madden
authors: David A
authors: DA
authors: Wood
authors: Cameron J
authors: CJ
authors: Hague
authors: Rohan
authors: R
authors: Poulter
authors: Kelly
authors: K
authors: Branch
authors: Ricardo C
authors: RC
authors: Cury
authors: Brett
authors: B
authors: Heilbron
authors: Carolyn
authors: C
authors: Taylor
authors: Gilat
authors: G
authors: Grunau
authors: Lawrence
authors: L
authors: Haiducu
authors: James K
authors: JK
authors: Min
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055424:Cardiac-Gated Imaging Techniques / Q000706:statistics & numerical data*; D017023:Coronary Angiography / Q000706:statistics & numerical data*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015995:Prevalence; D011446:Prospective Studies; D011829:Radiation Dosage; D011835:Radiation Protection / Q000706:statistics & numerical data; D011874:Radiometry / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology; D055815:Young Adult