title: Monochromatic image reconstruction by dual energy imaging allows half iodine load computed tomography coronary angiography.
abstract: OBJECTIVE
  To compare image interpretability and diagnostic performance of dual-energy CT coronary angiography (DE-CTCA) performed with 50% iodine load reduction versus single energy acquisitions (SE-CTCA) with full iodine load.
  
  
  METHODS
  The present prospective study involved patients with suspected coronary artery disease (CAD) clinically referred for CTCA. DE-CTCA with 50% iodine volume load was performed first, and after heart rate returned to baseline SE-CTCA was performed using full iodine volume load. The primary endpoint was to compare image interpretability between groups. DE-CTCA was performed by rapid switching between low and high tube potentials (80-140 kV) from a single source, allowing the generation of monochromatic image reconstructions ranging from 40 to 140 keV. Image quality assessment was performed using a 5-point Likert scale.
  
  
  RESULTS
  Thirty-six patients constituted the study population. The mean heart rate before the CT scan (DE-CTCA 57.3 ± 10.7 bpm vs. SE-CTCA 58.5 ± 11.2 bpm, p=0.29) and the mean effective radiation dose (3.5 ± 1.9 mSv vs. 3.8 ± 0.9 mSv, p=0.48) did not differ between groups. Likert image quality scores were similar between groups (DE-CTCA 4.42 ± 0.98 vs. SE-CTCA 4.43 ± 0.84, p=0.67). Signal-to-noise and contrast-to-noise ratios were significantly lower with DE-CTCA, driven by lower signal density levels at 60 keV compared to SE-CTCA. The sensitivity and specificity for the detection of stenosis >50% was indistinguishable between groups (DE-CTCA 84.4% (69.9-93.0%), 87.1% (81.6-91.2%); SE-CTCA 84.4% (69.9-93.0%), 87.1% (81.6-91.2%).
  
  
  CONCLUSIONS
  In this pilot, prospective study, dual energy CTCA imaging with half iodine load achieved comparable interpretability than full iodine load with single energy CTCA.
authors.affiliation: Department of Computed Tomography, Diagnostico Maipu, Buenos Aires, Argentina. Electronic address: investigacion@diagnosticomaipu.com.ar.
authors.forename: Patricia
authors.initials: P
authors.lastname: Carrascosa
authors.affiliation: Medical Imaging, St. Paul's Hospital, Vancouver, BC, Canada.
authors.forename: Jonathon A
authors.initials: JA
authors.lastname: Leipsic
authors.affiliation: Department of Computed Tomography, Diagnostico Maipu, Buenos Aires, Argentina.
authors.forename: Carlos
authors.initials: C
authors.lastname: Capunay
authors.affiliation: Department of Computed Tomography, Diagnostico Maipu, Buenos Aires, Argentina.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Deviggiano
authors.affiliation: Department of Computed Tomography, Diagnostico Maipu, Buenos Aires, Argentina.
authors.forename: Javier
authors.initials: J
authors.lastname: Vallejos
authors.affiliation: Department of Interventional Cardiology, Sanatorio Guemes, Buenos Aires, Argentina.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Goldsmit
authors.affiliation: Department of Computed Tomography, Diagnostico Maipu, Buenos Aires, Argentina.
authors.forename: Gaston A
authors.initials: GA
authors.lastname: Rodriguez-Granillo
mesh_terms: D000368:Aged; D016477:Artifacts; D003287:Contrast Media / Q000008:administration & dosage*; D017023:Coronary Angiography / Q000379:methods* / Q000706:statistics & numerical data; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods* / Q000706:statistics & numerical data; D007455:Iodine / Q000008:administration & dosage*; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement / Q000379:methods; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000706:statistics & numerical data
chemical_list: D003287:Contrast Media; D007455:Iodine
keywords: Atherosclerosis; Contrast material; Coronary artery disease; Imaging; Volume