title: Reduced iodine load with CT coronary angiography using dual-energy imaging: a prospective randomized trial compared with standard coronary CT angiography.
abstract: BACKGROUND
  There is concern regarding the administration of iodinated contrast to patients with impaired renal function because of the increased risk of contrast-induced nephropathy.
  
  
  OBJECTIVE
  Evaluate image quality and feasibility of a protocol with a reduced volume of iodinated contrast and utilization of dual-energy coronary CT angiography (DECT) vs a standard iodinated contrast volume coronary CT angiography protocol (SCCTA).
  
  
  METHODS
  A total of 102 consecutive patients were randomized to SCCTA (n = 53) or DECT with rapid kVp switching (n = 49). Eighty milliliters and 35 mL of iodinated contrast were administered in the SCCTA and DECT cohorts, respectively. Two readers measured signal and noise in the coronary arteries; signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. A 5-point signal/noise Likert scale was used to evaluate image quality; scores of <3 were nondiagnostic. Agreement was assessed through kappa analyses.
  
  
  RESULTS
  Demographics and radiation dose were not significantly different; there was no difference in CNR between both cohorts (P = .95). A significant difference in SNR between the groups (P = .02) lost significance (P = .13) when adjusted for body mass index. The median Likert score was inferior for DECT for reader 1 (3.6 ± 0.6 vs 4.3 ± 0.6; P < .001) but not reader 2 (4.1 ± 0.6 vs 4.3 ± 0.5; P = .06). Agreement in diagnostic interpretability in the DECT and SCCTA groups was 91% (95% confidence interval, 86%-100%) and 96% (95% confidence interval, 90%-100%), respectively.
  
  
  CONCLUSIONS
  DECT resulted in inferior image quality scores but demonstrated comparable SNR, CNR, and rate of diagnostic interpretability without a radiation dose penalty while allowing for >50% reduction in contrast volume compared with SCCTA.
authors.affiliation: Department of Radiology and Division of Cardiology, St Paul's Hospital, 1081 Burrard Street, Vancouver V6Z 1Y6, BC, Canada.
authors.forename: Rekha
authors.initials: R
authors.lastname: Raju
authors.affiliation: Department of Radiology and Division of Cardiology, St Paul's Hospital, 1081 Burrard Street, Vancouver V6Z 1Y6, BC, Canada.
authors.forename: Angus G
authors.initials: AG
authors.lastname: Thompson
authors.affiliation: Department of Radiology and Division of Cardiology, St Paul's Hospital, 1081 Burrard Street, Vancouver V6Z 1Y6, BC, Canada.
authors.forename: Kristy
authors.initials: K
authors.lastname: Lee
authors.affiliation: Department of Radiology and Division of Cardiology, St Paul's Hospital, 1081 Burrard Street, Vancouver V6Z 1Y6, BC, Canada.
authors.forename: Bruce
authors.initials: B
authors.lastname: Precious
authors.affiliation: Department of Radiology and Division of Cardiology, St Paul's Hospital, 1081 Burrard Street, Vancouver V6Z 1Y6, BC, Canada.
authors.forename: Tae-Hyun
authors.initials: TH
authors.lastname: Yang
authors.affiliation: Department of Radiology and Division of Cardiology, St Paul's Hospital, 1081 Burrard Street, Vancouver V6Z 1Y6, BC, Canada.
authors.forename: Adam
authors.initials: A
authors.lastname: Berger
authors.affiliation: Department of Radiology and Division of Cardiology, St Paul's Hospital, 1081 Burrard Street, Vancouver V6Z 1Y6, BC, Canada.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Taylor
authors.affiliation: Department of Radiology and Division of Cardiology, St Paul's Hospital, 1081 Burrard Street, Vancouver V6Z 1Y6, BC, Canada.
authors.forename: Brett
authors.initials: B
authors.lastname: Heilbron
authors.affiliation: Department of Radiology and Division of Cardiology, St Paul's Hospital, 1081 Burrard Street, Vancouver V6Z 1Y6, BC, Canada.
authors.forename: Giang
authors.initials: G
authors.lastname: Nguyen
authors.affiliation: Fairfax Radiology, Virginia, USA.
authors.forename: James
authors.initials: J
authors.lastname: Earls
authors.affiliation: New York Presbyterian/Weil Cornell Medical College, New York, NY, USA.
authors.forename: James
authors.initials: J
authors.lastname: Min
authors.affiliation: Department of Radiology, Buenos Aires University School of Medicine, Buenos Aires, Argentina.
authors.forename: Patricia
authors.initials: P
authors.lastname: Carrascosa
authors.affiliation: Department of Radiology and Division of Cardiology, St Paul's Hospital, 1081 Burrard Street, Vancouver V6Z 1Y6, BC, Canada.
authors.forename: Darra
authors.initials: D
authors.lastname: Murphy
authors.affiliation: Department of Radiology and Division of Cardiology, St Paul's Hospital, 1081 Burrard Street, Vancouver V6Z 1Y6, BC, Canada.
authors.forename: Cameron
authors.initials: C
authors.lastname: Hague
authors.affiliation: Department of Radiology and Division of Cardiology, St Paul's Hospital, 1081 Burrard Street, Vancouver V6Z 1Y6, BC, Canada. Electronic address: jleipsic@providencehealth.bc.ca.
authors.forename: Jonathon A
authors.initials: JA
authors.lastname: Leipsic
mesh_terms: D001955:British Columbia; D003287:Contrast Media / Q000009:adverse effects; D017023:Coronary Angiography / Q000379:methods*; D004311:Double-Blind Method; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000139:chemically induced / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D015203:Reproducibility of Results; D012307:Risk Factors; D059629:Signal-To-Noise Ratio; D014057:Tomography, X-Ray Computed; D014283:Triiodobenzoic Acids / Q000009:adverse effects
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C044834:iodixanol
keywords: Coronary CT angiography; Diagnostic Efficacy; Dual energy CT; Image quality; Reduced iodinated contrast