title: Coronary Stent Artifact Reduction with an Edge-Enhancing Reconstruction Kernel - A Prospective Cross-Sectional Study with 256-Slice CT.
abstract: Metallic artifacts can result in an artificial thickening of the coronary stent wall which can significantly impair computed tomography (CT) imaging in patients with coronary stents. The objective of this study is to assess in vivo visualization of coronary stent wall and lumen with an edge-enhancing CT reconstruction kernel, as compared to a standard kernel.
  
  
  
  This is a prospective cross-sectional study involving the assessment of 71 coronary stents (24 patients), with blinded observers. After 256-slice CT angiography, image reconstruction was done with medium-smooth and edge-enhancing kernels. Stent wall thickness was measured with both orthogonal and circumference methods, averaging thickness from diameter and circumference measurements, respectively. Image quality was assessed quantitatively using objective parameters (noise, signal to noise (SNR) and contrast to noise (CNR) ratios), as well as visually using a 5-point Likert scale.
  
  
  
  Stent wall thickness was decreased with the edge-enhancing kernel in comparison to the standard kernel, either with the orthogonal (0.97 ± 0.02 versus 1.09 ± 0.03 mm, respectively; p<0.001) or the circumference method (1.13 ± 0.02 versus 1.21 ± 0.02 mm, respectively; p = 0.001). The edge-enhancing kernel generated less overestimation from nominal thickness compared to the standard kernel, both with the orthogonal (0.89 ± 0.19 versus 1.00 ± 0.26 mm, respectively; p<0.001) and the circumference (1.06 ± 0.26 versus 1.13 ± 0.31 mm, respectively; p = 0.005) methods. The edge-enhancing kernel was associated with lower SNR and CNR, as well as higher background noise (all p < 0.001), in comparison to the medium-smooth kernel. Stent visual scores were higher with the edge-enhancing kernel (p<0.001).
  
  
  
  In vivo 256-slice CT assessment of coronary stents shows that the edge-enhancing CT reconstruction kernel generates thinner stent walls, less overestimation from nominal thickness, and better image quality scores than the standard kernel.
authors.affiliation: Radiology, University of Montreal Medical Center (CHUM), Montreal, Canada.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Tan
authors.affiliation: Radiology, University of Montreal Medical Center (CHUM), Montreal, Canada.|University of Montreal Medical Center Research Center, Montreal, Canada.
authors.forename: Gilles
authors.initials: G
authors.lastname: Soulez
authors.affiliation: Radiology, Centre Hospitalier Universitaire de Sherbrooke (CHUS), Sherbrooke, Canada.
authors.forename: Patricia
authors.initials: P
authors.lastname: Diez Martinez
authors.affiliation: University of Montreal Medical Center Research Center, Montreal, Canada.|Biostatistics, Pennington Biomedical Research Center, Bâton Rouge, Louisiana, United States of America.
authors.forename: Sandra
authors.initials: S
authors.lastname: Larrivée
authors.affiliation: University of Montreal Medical Center Research Center, Montreal, Canada.|Cardiac Surgery, University of Montreal Medical Center (CHUM), Montreal, Canada.
authors.forename: Louis-Mathieu
authors.initials: LM
authors.lastname: Stevens
authors.affiliation: Electrical Engineering, Ecole Polytechnique de Montréal, Montreal, Canada.
authors.forename: Yves
authors.initials: Y
authors.lastname: Goussard
authors.affiliation: University of Montreal Medical Center Research Center, Montreal, Canada.|Cardiology, University of Montreal Medical Center (CHUM), Montreal, Canada.
authors.forename: Samer
authors.initials: S
authors.lastname: Mansour
authors.affiliation: Radiology, University of Montreal Medical Center (CHUM), Montreal, Canada.|University of Montreal Medical Center Research Center, Montreal, Canada.
authors.forename: Carl
authors.initials: C
authors.lastname: Chartrand-Lefebvre
mesh_terms: D000368:Aged; D016477:Artifacts; D017023:Coronary Angiography / Q000379:methods*; D003331:Coronary Vessels / Q000473:pathology / Q000601:surgery*; D003430:Cross-Sectional Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008670:Metals; D008875:Middle Aged; D011446:Prospective Studies; D059629:Signal-To-Noise Ratio; D062206:Spatial Analysis; D015607:Stents; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D008670:Metals