The simulation of magnetic resonance elastography through atherosclerosis

Research output: Contribution to journalArticle

Authors

  • Lyam Hollis
  • Dieter Klatt
  • Ingolf Sack
  • Neil Roberts
  • Pankaj Pankaj
  • Peter Hoskins

Colleges, School and Institutes

External organisations

  • University of Edinburgh
  • Charité Universitätsmedizin, Berlin, Germany.

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.

Details

Original languageEnglish
Pages (from-to)1781-1788
Number of pages8
JournalJournal of Biomechanics
Volume49
Issue number9
Early online date16 Apr 2016
Publication statusPublished - 14 Jun 2016

Keywords

  • Finite element analysis (FEA), Atherosclerosis, Elastography, Magnetic resonance elastography (MRE)