title: Prospective-triggered sequential dual-source end-systolic coronary CT angiography for patients with atrial fibrillation: a feasibility study.
abstract: BACKGROUND
  Obtaining diagnostic coronary CT angiography with low radiation exposure in patients with irregular heart rhythms such as atrial fibrillation (AF) remains challenging.
  
  
  OBJECTIVE
  We evaluated image quality and inter-reader variability with the use of prospective electrocardiographic (ECG)-triggered sequential dual-source acquisition at end systole for coronary artery disease (CAD) evaluation in patients with AF.
  
  
  METHODS
  Thirty consecutive patients with AF who underwent prospective ECG-triggered sequential dual-source acquisition were evaluated. Images were reconstructed every 50 milliseconds from 250 to 400 milliseconds after the R wave. Two independent, blinded readers evaluated the coronaries for image quality on a 5-point scale (worst to best) and stenosis on 5-point semiquantitative (none to severe) and binary scales (>50% or <50%). Diagnostic image quality was graded for each reconstruction.
  
  
  RESULTS
  Eleven patients (37%) had significant (≥50% stenosis) CAD. Average heart rate was 82 ± 20 beats/min and variability range was 71 ± 22 beats/min. Mean effective radiation dose was 6.5 ± 2.4 mSv. Diagnostic image quality was noted in 97.9% of 304 coronary segments with median image quality of 3.0. The 300-millisecond reconstruction phase provided the highest image quality; 70% of patients showed diagnostic image quality. Combination of all phases (250-400 milliseconds) performed significantly better than single or other phase combinations (P < 0.0005 for all comparisons). Inter-reader variability for stenosis detection was excellent, with 98.4% concordance by using a binary scale (50% stenosis cutoff).
  
  
  CONCLUSIONS
  Prospective ECG-triggered sequential dual-source CT acquisition with the use of end-systolic acquisition provides diagnostic image quality with potentially low radiation doses for evaluation of CAD in patients with AF. Use of multiple end-systolic phases over a 150-millisecond window improves diagnostic image quality.
authors.affiliation: Department of Medicine, Cardiology Division, Medstar Georgetown University Hospital, 3800 Reservoir Road NW, 5PHC, Washington, DC 20007, USA. srichai@alum.mit.edu
authors.forename: Monvadi B
authors.initials: MB
authors.lastname: Srichai
authors.forename: Mitya
authors.initials: M
authors.lastname: Barreto
authors.forename: Ruth P
authors.initials: RP
authors.lastname: Lim
authors.forename: Robert
authors.initials: R
authors.lastname: Donnino
authors.forename: James S
authors.initials: JS
authors.lastname: Babb
authors.forename: Jill E
authors.initials: JE
authors.lastname: Jacobs
mesh_terms: D000465:Algorithms; D001281:Atrial Fibrillation / Q000150:complications / Q000000981:diagnostic imaging*; D055424:Cardiac-Gated Imaging Techniques / Q000379:methods*; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*