Anisotropic elastic moduli reconstruction in transversely isotropic model using MRE

Abstract

Magnetic resonance elastography (MRE) is an elastic tissue property imaging modality in which the phase-contrast based MRI imaging technique is used to measure internal displacement induced by a harmonically oscillating mechanical vibration. MRE has made rapid technological progress in the past decade and has now reached the stage of clinical use. Most of the research outcomes are based on the assumption of isotropy. Since soft tissues like skeletal muscles show anisotropic behavior, the MRE technique should be extended to anisotropic elastic property imaging. This paper considers reconstruction in a transversely isotropic model, which is the simplest case of anisotropy, and develops a new non-iterative reconstruction method for visualizing the elastic moduli distribution. This new method is based on an explicit representation formula using the Newtonian potential of measured displacement. Hence, the proposed method does not require iterations since it directly recovers the anisotropic elastic moduli. We perform numerical simulations in order to demonstrate the feasibility of the proposed method in recovering a twodimensional anisotropic tensor.

Magnetic resonance elastography of skeletal muscle deep tissue injury

“…61,62 Others proposed the use of a linear (visco) elastic transverse isotropic material approach as an intermediate solution. [63][64][65][66] Using this approach, Qin et al found a decrease in anisotropic ratio, related to necrosis, in an MDX mouse model of diseased skeletal muscle. 67 However, to date the transverse isotropic MRE inversion is still rarely used, as muscle fiber directions obtained, for example by diffusion tensor imaging (DTI), are needed as input.…”

“…Although this approach is used by several groups, it is a simplification for skeletal muscle which generally exhibits nonlinear viscoelastic anisotropic material behavior . Others proposed the use of a linear (visco) elastic transverse isotropic material approach as an intermediate solution . Using this approach, Qin et al found a decrease in anisotropic ratio, related to necrosis, in an MDX mouse model of diseased skeletal muscle .…”

Viscoelastic Modulus Reconstruction Using Time Harmonic Vibrations

“…Although significant progress has been made in the development of shear modulus imaging technology, problems remain image quality relating to the enhancement of images of local tissue shear viscosity and shear modulus [10,13,15,19,29,30,31,35]. This paper focuses on the image reconstruction methods for tissue viscoelasticity imaging.…”

Magnetic Resonance Imaging of Pediatric Muscular Disorders

“…78 One of the main limitations of MR elastography of the muscle is that the stiffness is still assessed with a manual technique, which could show subjective variation, but ongoing work in this domain may address this issue in the near future. 79 …”