title: Assessment of left ventricular ejection fraction using low radiation dose computed tomography.
abstract: Cardiac CT is a non-invasive modality with the ability to estimate LVEF. However, given its limited temporal resolution and radiation, there has been initial resistance to use CT to measure LVEF. Developing an accurate, fast, low radiation dose protocol is desirable.
  
  
  
  The objective of this study is to demonstrate that a 'low radiation dose' 64 slice cardiac computed tomography (CT) protocol is feasible and can accurately measure left ventricular ejection fraction (LVEF) while delivering a radiation dose lower than radionuclide angiography (RNA).
  
  
  
  Patients undergoing RNA were prospectively screened and enrolled to undergo a 'low-dose' 64 slice CT LVEF protocol. LVEF measures, duration of each study and radiation dose between CT and RNA were compared.
  
  
  
  A total of 77 patients (mean age = 61.8 ± 12.2 years and 58 men) were analyzed. The mean LVEF measured by CT and RNA were 41.9 ± 15.2% and 39.4 ± 13.9%, respectively, (P = 0.154) with a good correlation (r = 0.863). Bland-Altman plot revealed a good agreement between the CT and RNA LVEF (mean difference of -2.4). There was good agreement between CT LVEF and RNA for identifying patients with LVEF ≤30% (kappa = 0.693) and LVEF ≥50% (kappa = 0.749). The mean dose estimated effective dose for CT and RNA were 4.7 ± 1.6 and 9.5 ± 1.0 mSv, respectively. The mean CT LVEF imaging duration (4:32 ± 3:05 minutes) was significantly shorter than the RNA image acquisition time (9:05 ± 2:36 minutes; p < 0.001).
  
  
  
  The results of our study suggest that low-dose CT LVEF protocol is feasible, accurate, and fast while delivering a lower radiation dose than traditional RNA.
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON, K1Y 4W7, Canada.
authors.forename: YiQi
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON, K1Y 4W7, Canada.
authors.forename: Yeung
authors.initials: Y
authors.lastname: Yam
authors.affiliation: Cardiovascular Research Methods Centre, University of Ottawa Heart Institute, Ottawa, Canada.
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON, K1Y 4W7, Canada.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Aljizeeri
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON, K1Y 4W7, Canada.
authors.forename: Siamak
authors.initials: S
authors.lastname: Aliyary Ghraboghly
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON, K1Y 4W7, Canada.
authors.forename: Ibraheem
authors.initials: I
authors.lastname: Al-Harbi
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON, K1Y 4W7, Canada.
authors.forename: Ally
authors.initials: A
authors.lastname: Pen
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON, K1Y 4W7, Canada.|Department of Radiology, University of Ottawa, Ottawa, Canada.
authors.forename: Terrence D
authors.initials: TD
authors.lastname: Ruddy
authors.affiliation: Division of Cardiology, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, ON, K1Y 4W7, Canada. bchow@ottawaheart.ca.|Department of Radiology, University of Ottawa, Ottawa, Canada. bchow@ottawaheart.ca.
authors.forename: Benjamin J W
authors.initials: BJ
authors.lastname: Chow
mesh_terms: D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011875:Radionuclide Angiography / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D014057:Tomography, X-Ray Computed / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*
keywords: Computed tomography; ejection fraction; radionuclide angiography