Diagnostic value of MR elastography in addition to contrast-enhanced MR imaging of the breast—initial clinical results

Siegmann, K. C.; Xydeas, T.; Sinkus, Ralph; Kraemer, Bernhard; Vogel, U.; Claussen, Claus D.

doi:10.1007/s00330-009-1566-4

Cited by 65 publications

(73 citation statements)

References 32 publications

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“…Magnetic resonance elastography (MRE) is a technique to produce images of tissue mechanical properties, where changes in shear modulus have been linked to diseases in organs including the brain, [1][2][3] liver, 4 breast, 5 and heart. 6,7 In MRE, motion sensitive MRI sequences are employed to measure the displacement of tissue resulting from some mechanical stimulus.…”

Section: Introductionmentioning

confidence: 99%

Suitability of poroelastic and viscoelastic mechanical models for high and low frequency MR elastography

et al. 2015

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Purpose: Descriptions of the structure of brain tissue as a porous cellular matrix support application of a poroelastic (PE) mechanical model which includes both solid and fluid phases. However, the majority of brain magnetic resonance elastography (MRE) studies use a single phase viscoelastic (VE) model to describe brain tissue behavior, in part due to availability of relatively simple direct inversion strategies for mechanical property estimation. A notable exception is low frequency intrinsic actuation MRE, where PE mechanical properties are imaged with a nonlinear inversion algorithm. Methods: This paper investigates the effect of model choice at each end of the spectrum of in vivo human brain actuation frequencies. Repeat MRE examinations of the brains of healthy volunteers were used to compare image quality and repeatability for each inversion model for both 50 Hz externally produced motion and ≈1 Hz intrinsic motions. Additionally, realistic simulated MRE data were generated with both VE and PE finite element solvers to investigate the effect of inappropriate model choice for ideal VE and PE materials. Results: In vivo, MRE data revealed that VE inversions appear more representative of anatomical structure and quantitatively repeatable for 50 Hz induced motions, whereas PE inversion produces better results at 1 Hz. Reasonable VE approximations of PE materials can be derived by equating the equivalent wave velocities for the two models, provided that the timescale of fluid equilibration is not similar to the period of actuation. An approximation of the equilibration time for human brain reveals that this condition is violated at 1 Hz but not at 50 Hz. Additionally, simulation experiments when using the "wrong" model for the inversion demonstrated reasonable shear modulus reconstructions at 50 Hz, whereas cross-model inversions at 1 Hz were poor quality. Attenuation parameters were sensitive to changes in the forward model at both frequencies, however, no spatial information was recovered because the mechanisms of VE and PE attenuation are different. Conclusions: VE inversions are simpler with fewer unknown properties and may be sufficient to capture the mechanical behavior of PE brain tissue at higher actuation frequencies. However, accurate modeling of the fluid phase is required to produce useful mechanical property images at the lower

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Section: Introductionmentioning

confidence: 99%

Suitability of poroelastic and viscoelastic mechanical models for high and low frequency MR elastography

et al. 2015

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“…Tumour size is usually assessed using a clinical examination, mammography, ultrasound and magnetic resonance imaging of the breast, or combinations of these methods [6][7][8][9]. Mammographic and ultrasound assessment of tumour size have been described previously elsewhere.…”

Section: Introductionmentioning

confidence: 99%

Assessment of breast cancer tumour size using six different methods

Meier-Meitinger

Häberle²,

Fasching³

et al. 2010

Eur Radiol

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“…In vivo MRE has been successfully applied to reveal the stiffness of a variety of human tissues and organs such as the brain [4] [6], breast [4] [7], liver [4] [8], prostate [9] [10], and skeletal muscles [4] [10].…”

Section: Introductionmentioning

confidence: 99%

Partial Volume Effect on MR Elastography

Ito¹,

Numano²,

Mizuhara³

et al. 2017

OJMI

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Magnetic resonance elastography (MRE) allows the quantitative assessment of the stiffness of tissues based on the tissue response to oscillatory shear stress. Shear wave displacements of the tissues are encoded as phase shifts and converted to stiffness (elastogram). Generally, a partial volume effect occurs when different materials are encompassed on the same voxel. In MRE, however, the partial volume effect occurs even if the voxel is filled with the same materials because wave displacements due to vibrations are spatially distributed. The purpose of this study was to investigate how the partial volume effect can affect the phase shift and the elastogram in MRE. We assumed that the partial volume effect appears only in the slice thickness direction and performed a simulation and MRE experiment with various slice thicknesses (1 -19 mm), two types of imaging plane (coronal and axial) and two types of vibration frequency (100 and 200 Hz). The results of the simulation and the MRE experiment were similar, and indicated that the phase shift and the elastogram changed variously depending on the slice thickness, the wave pattern and the vibration frequency, even if the voxel was filled with the same material. To reduce the partial volume effect, it is necessary to perform the MRE under the following conditions: Use a wave pattern which barely causes this artefact, a smaller voxel size and a lower vibration frequency.

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Diagnostic value of MR elastography in addition to contrast-enhanced MR imaging of the breast—initial clinical results

Abstract: In this study, the combination of MRE and ce MRI could increase the diagnostic performance of breast MRI. Further investigations of larger cohorts and smaller lesions (in particular those only visible on MRI) are necessary to validate these results.

Cited by 65 publications

References 32 publications

Suitability of poroelastic and viscoelastic mechanical models for high and low frequency MR elastography

Suitability of poroelastic and viscoelastic mechanical models for high and low frequency MR elastography

Assessment of breast cancer tumour size using six different methods

Partial Volume Effect on MR Elastography

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