Application of DENSE‐MR‐elastography to the human heart

Robert, Benjamin; Sinkus, Ralph; Gennisson, Jean‐Luc; Fink, Mathias

doi:10.1002/mrm.22124

Cited by 46 publications

(61 citation statements)

References 32 publications

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“…Contrary to ultrasound, MRI is not capable to acquire the displacement field in real-time. The finite sampling provides in return broad-band sensitivity which can be used to accelerate or improve data acquisition [25,26].…”

Section: Mr-elastography Data Acquisition and Reconstructionmentioning

confidence: 99%

Elasticity Imaging via MRI: Basics, Overcoming the Waveguide Limit, and Clinical Liver Results

Sinkus¹,

Daire²,

Vilgrain³

et al. 2012

CMIR

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Elasticity imaging is a rather recent non-invasive imaging modality which provides in-vivo data about the viscoelastic properties of tissue. With manual palpation being an integral part of many diagnostic procedures, it is obvious that elasticity imaging has many interesting and promising potentials in medical imaging, i.e. from tissue/lesion characterization over therapy follow-up to guidance during interventions which involve ablation. The general concept of this method is to displace the material mechanically and infer from displacement measurements the intrinsic local viscoelastic properties. Many different technical realizations exist (static, dynamic, transient) utilizing different imaging modalities (MRI, ultrasound) which all probe different frequency domains. Since viscoelastic properties of tissue change strongly with frequency, care must be taken when interpreting the data in terms of elastic and viscous component. In this review we will focus on the dynamic 3D approach via MRI, i.e. a mono-frequent mechanical excitation and a volumetric assessment of the displacement field. This allows overcoming several physical difficulties: firstly compressional waves can be properly suppressed via the application of the curl-operator, secondly waveguide effects are eliminated and finally the calculation of the complex shear modulus does not necessitate any assumption of the underlying rheological model. Clinical results on a large patient collective show that mechanical parameters are very pertinent for the differentiation between low-grade and mid/high-grade liver fibrosis. They outperform the well establish classical APRI blood test as well as a 1D ultrasound-based approach for elasticity imaging.

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Section: Mr-elastography Data Acquisition and Reconstructionmentioning

confidence: 99%

Elasticity Imaging via MRI: Basics, Overcoming the Waveguide Limit, and Clinical Liver Results

Sinkus¹,

Daire²,

Vilgrain³

et al. 2012

CMIR

Self Cite

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“…A faster imaging method was therefore required. Uses of single-shot EPI sequences for MRE had been published before [32,45,79], but they were limited to low spatial resolutions (or small fields of view) and were not widely adapted for diagnostic purposes. Therefore, the development of a new and improved version of a motion-sensitized single-shot EPI sequence was the first part of the work described in this thesis.…”

Section: Signal Equationmentioning

confidence: 99%

Compression-sensitive magnetic resonance elastography

et al. 2013

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ZusammenfassungResults illustrate that compression-sensitive MRE is capable of quantifying volumetric strain in phantoms and in human organs. It was found that volumetric strain was sensitive toward pressure changes associated with different physiological states, whereas shear strain remained constant.In an additional study, pulsation of the human brain, driven by the heart cycle, was used as the actuation source instead of the external vibration generator. Volumetric strain velocity was tracked over the cardiac cycle. Results indicate local expansion of brain parenchyma upon the arrival of the arterial pulse wave, followed by a slow return to the initial state during the diastolic phase.Numerical values for the pressure wave modulus M were calculated from measured volumetric strain through inversion of the pressure wave equation. Measurement noise was identified as the primary effect causing a severe underestimation of M .

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“…Plewes et al, (2000) estimated isotropic elastic properties of breast tissue, whereas Sinkus et al (2005a, 2005b) probed both isotropic and anisotropic viscoelastic properties. MRE has been applied to the human brain (Kruse et al, 2008, Hamhaber et al, 2007), liver (Asbach et al, 2008, Rouviere et al, 2006, Yin et al, 2007a), heart (Elgeti et al, 2008, Sack et al, 2009, Robert et al, 2009), and prostate (Kemper et al, 2004). …”

Section: Introductionmentioning

confidence: 99%

Frequency-dependent viscoelastic parameters of mouse brain tissue estimated by MR elastography

2011

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Viscoelastic properties of mouse brain tissue were estimated non-invasively, in vivo, using magnetic resonance elastography (MRE) at 4.7 T to measure the dispersive properties of induced shear waves. Key features of this study include: (i) the development and application of a novel MR-compatible actuation system which transmits vibratory motion into the brain through an incisor bar; and (ii) the investigation of the mechanical properties of brain tissue over a 1200 Hz bandwidth from 600 Hz –1800 Hz. Displacement fields due to propagating shear waves were measured during continuous, harmonic excitation of the skull. This protocol enabled characterization of the true steady-state patterns of shear wave propagation. Analysis of displacement fields obtained at different frequencies indicates that the viscoelastic properties of mouse brain tissue depend strongly on frequency. The average storage modulus (G') increased from approximately 1.6 kPa to 8 kPa over this range; average loss modulus (G”) increased from approximately 1 kPa to 3 kPa. Both moduli were well-approximated by a power-law relationship over this frequency range. MRE may be a valuable addition to studies of disease in murine models, and to pre-clinical evaluations of therapies. Quantitative measurements of the viscoelastic parameters of brain tissue at high frequencies are also valuable for modeling and simulation of traumatic brain injury (TBI).

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Application of DENSE‐MR‐elastography to the human heart

Cited by 46 publications

References 32 publications

Elasticity Imaging via MRI: Basics, Overcoming the Waveguide Limit, and Clinical Liver Results

Elasticity Imaging via MRI: Basics, Overcoming the Waveguide Limit, and Clinical Liver Results

Compression-sensitive magnetic resonance elastography

Frequency-dependent viscoelastic parameters of mouse brain tissue estimated by MR elastography

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