title: The simulation of magnetic resonance elastography through atherosclerosis.
abstract: The clinical diagnosis of atherosclerosis via the measurement of stenosis size is widely acknowledged as an imperfect criterion. The vulnerability of an atherosclerotic plaque to rupture is associated with its mechanical properties. The potential to image these mechanical properties using magnetic resonance elastography (MRE) was investigated through synthetic datasets. An image of the steady state wave propagation, equivalent to the first harmonic, can be extracted directly from finite element analysis. Inversion of this displacement data yields a map of the shear modulus, known as an elastogram. The variation of plaque composition, stenosis size, Gaussian noise, filter thresholds and excitation frequency were explored. A decreasing mean shear modulus with an increasing lipid composition was identified through all stenosis sizes. However the inversion algorithm showed sensitivity to parameter variation leading to artefacts which disrupted both the elastograms and quantitative trends. As noise was increased up to a realistic level, the contrast was maintained between the fully fibrous and lipid plaques but lost between the interim compositions. Although incorporating a Butterworth filter improved the performance of the algorithm, restrictive filter thresholds resulted in a reduction of the sensitivity of the algorithm to composition and noise variation. Increasing the excitation frequency improved the techniques ability to image the magnitude of the shear modulus and identify a contrast between compositions. In conclusion, whilst the technique has the potential to image the shear modulus of atherosclerotic plaques, future research will require the integration of a heterogeneous inversion algorithm.
authors.affiliation: Centre for Cardiovascular Science, University of Edinburgh, Queen׳s Medical Research Institute, 47 Little France Crescent, Edinburgh, UK. Electronic address: l.e.j.thomas-seale@bham.ac.uk.
authors.forename: L E J
authors.initials: LEJ
authors.lastname: Thomas-Seale
authors.affiliation: Centre for Cardiovascular Science, University of Edinburgh, Queen׳s Medical Research Institute, 47 Little France Crescent, Edinburgh, UK.
authors.forename: L
authors.initials: L
authors.lastname: Hollis
authors.affiliation: Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Klatt
authors.affiliation: Department of Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Sack
authors.affiliation: Clinical Research Imaging Centre, University of Edinburgh, 47 Little France Crescent, Edinburgh, UK.
authors.forename: N
authors.initials: N
authors.lastname: Roberts
authors.affiliation: School of Engineering, University of Edinburgh, Alexander Graham Bell Building, The King׳s Buildings, Edinburgh, UK.
authors.forename: P
authors.initials: P
authors.lastname: Pankaj
authors.affiliation: Centre for Cardiovascular Science, University of Edinburgh, Queen׳s Medical Research Institute, 47 Little France Crescent, Edinburgh, UK.
authors.forename: P R
authors.initials: PR
authors.lastname: Hoskins
mesh_terms: D000465:Algorithms; D050197:Atherosclerosis / Q000000981:diagnostic imaging*; D054459:Elasticity Imaging Techniques / Q000379:methods*; D020342:Finite Element Analysis; D006801:Humans
keywords: Atherosclerosis; Elastography; Finite element analysis (FEA); Magnetic resonance elastography (MRE)