title: A computer-simulation study on the effects of MRI voxel dimensions on carotid plaque lipid-core and fibrous cap segmentation and stress modeling.
abstract: BACKGROUND
  The benefits of a decreased slice thickness and/or in-plane voxel size in carotid MRI for atherosclerotic plaque component quantification accuracy and biomechanical peak cap stress analysis have not yet been investigated in detail because of practical limitations.
  
  
  METHODS
  In order to provide a methodology that allows such an investigation in detail, numerical simulations of a T1-weighted, contrast-enhanced, 2D MRI sequence were employed. Both the slice thickness (2 mm, 1 mm, and 0.5 mm) and the in plane acquired voxel size (0.62x0.62 mm2 and 0.31x0.31 mm2) were varied. This virtual MRI approach was applied to 8 histology-based 3D patient carotid atherosclerotic plaque models.
  
  
  RESULTS
  A decreased slice thickness did not result in major improvements in lumen, vessel wall, and lipid-rich necrotic core size measurements. At 0.62x0.62 mm2 in-plane, only a 0.5 mm slice thickness resulted in improved minimum fibrous cap thickness measurements (a 2-3 fold reduction in measurement error) and only marginally improved peak cap stress computations. Acquiring voxels of 0.31x0.31 mm2 in-plane, however, led to either similar or significantly larger improvements in plaque component quantification and computed peak cap stress.
  
  
  CONCLUSIONS
  This study provides evidence that for currently-used 2D carotid MRI protocols, a decreased slice thickness might not be more beneficial for plaque measurement accuracy than a decreased in-plane voxel size. The MRI simulations performed indicate that not a reduced slice thickness (i.e. more isotropic imaging), but the acquisition of anisotropic voxels with a relatively smaller in-plane voxel size could improve carotid plaque quantification and computed peak cap stress accuracy.
authors: Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands.
authors: Harm A
authors: HA
authors: Nieuwstadt
authors: Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands; Department of Radiology, Erasmus MC, Rotterdam, the Netherlands.
authors: Zaid A M
authors: ZA
authors: Kassar
authors: Department of Radiology, Erasmus MC, Rotterdam, the Netherlands.
authors: Aad
authors: A
authors: van der Lugt
authors: Philips Healthcare, Best, the Netherlands; Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, the Netherlands.
authors: Marcel
authors: M
authors: Breeuwer
authors: Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands; Department of Imaging Science and Technology, Delft University of Technology, Delft, the Netherlands.
authors: Anton F W
authors: AF
authors: van der Steen
authors: Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands.
authors: Jolanda J
authors: JJ
authors: Wentzel
authors: Department of Biomedical Engineering, Erasmus MC, Rotterdam, the Netherlands.
authors: Frank J H
authors: FJ
authors: Gijsen
mesh_terms: D016880:Anisotropy; D002339:Carotid Arteries / Q000378:metabolism / Q000473:pathology; D016893:Carotid Stenosis / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D003198:Computer Simulation; D006801:Humans; D008055:Lipids / Q000737:chemistry; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008955:Models, Cardiovascular; D058226:Plaque, Atherosclerotic / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology
chemical_list: D008055:Lipids