title: First experience with single-source, dual-energy CCTA for monochromatic stent imaging.
abstract: OBJECTIVE
  Single-source, dual-energy coronary computed tomography angiography (CCTA) with monochromatic image reconstruction allows significant noise reduction. The aim of the study was to evaluate the impact of monochromatic CCTA image reconstruction on coronary stent imaging, as the latter is known to be affected by artefacts from highly attenuating strut material resulting in artificial luminal narrowing.
  
  
  RESULTS
  Twenty-one patients with 62 stents underwent invasive coronary angiography and single-source, dual-energy CCTA after stent implantation. Standard polychromatic images as well as eight monochromatic series (50, 60, 70, 80, 90, 100, 120, and 140 keV) were reconstructed for each CCTA. Signal and noise were measured within the stent lumen and in the aortic root. Mean in-stent luminal diameter was assessed in all CCTA reconstructions and compared with quantitative invasive coronary angiography (QCA). Luminal attenuation was higher in the stent than in the aortic root throughout all monochromatic reconstructions (P < 0.001). An increase in monochromatic energy was associated with a decrease in luminal attenuation values (P < 0.001). The mean in-stent luminal diameter underestimation by monochromatic CCTA compared with QCA was 90% at low monochromatic energy (50 keV) and improved to 37% at high monochromatic (140 keV) reconstruction while stent diameter was underestimated by 39% with standard CCTA.
  
  
  CONCLUSIONS
  Monochromatic CCTA can be used reliably in patients with coronary stents. However, reconstructions with energies below 80 keV are not recommended as the blooming artefacts are most pronounced at such low energies, resulting in up to 90% stent diameter underestimation.
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, CH-8091 Zurich, Switzerland.
authors.forename: Julia
authors.initials: J
authors.lastname: Stehli
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, CH-8091 Zurich, Switzerland.
authors.forename: Tobias A
authors.initials: TA
authors.lastname: Fuchs
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, CH-8091 Zurich, Switzerland.
authors.forename: Adrian
authors.initials: A
authors.lastname: Singer
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, CH-8091 Zurich, Switzerland.
authors.forename: Sacha
authors.initials: S
authors.lastname: Bull
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, CH-8091 Zurich, Switzerland.
authors.forename: Olivier F
authors.initials: OF
authors.lastname: Clerc
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, CH-8091 Zurich, Switzerland.
authors.forename: Mathias
authors.initials: M
authors.lastname: Possner
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, CH-8091 Zurich, Switzerland Department of Cardiology, University Hospital Zurich, Ramistrasse 100, NUK C 42, CH-8091 Zurich, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Gaemperli
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, CH-8091 Zurich, Switzerland.
authors.forename: Ronny R
authors.initials: RR
authors.lastname: Buechel
authors.affiliation: Department of Nuclear Medicine, Cardiac Imaging, University Hospital Zurich, CH-8091 Zurich, Switzerland pak@usz.ch.
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Kaufmann
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D055424:Cardiac-Gated Imaging Techniques; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D062645:Percutaneous Coronary Intervention; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D012680:Sensitivity and Specificity; D015607:Stents; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014283:Triiodobenzoic Acids
chemical_list: D003287:Contrast Media; D014283:Triiodobenzoic Acids; C044834:iodixanol
keywords: Gemstone Spectral Imaging; single-source dual-energy CCTA; stent imaging