Passive elastography: shear-wave tomography from physiological-noise correlation in soft tissues

Gallot, Thomas; Catheline, Stéfan; Roux, Philippe; Brum, Javier; Benech, N.; Negreira, Carlos

doi:10.1109/tuffc.2011.1920

Cited by 90 publications

(90 citation statements)

References 28 publications

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“…9 One component (along the z direction) of the complex elastic field is measured in the (x,z) plane by a standard speckle tracking technique, 29,30 using an ultrasonic linear 64 element array, 6 MHz central frequency, and an ultrafast scanner (1000 fps, Lecoeur Electronique, France). In each experiment, long duration signals of total time T ¼ 6 s are acquired sampled at 1000 Hz.…”

Section: Experimental Implementationmentioning

confidence: 99%

“…A non-exhaustive list includes ultrasound, 1 room acoustics, 2 seismology, 3,4 helioseismology, 5 ocean acoustics, 6 and elastography. [7][8][9] The resulting Green's function is the field that would be recorded in one of the observing points if there were an impulsive source at the other. Because there are no real sources at this point, the term virtual source has been used to denote the observed fields.…”

Section: Introductionmentioning

confidence: 99%

“…21,22 In a previous work, the shear elastic modulus of human liver was estimated in vivo from cross-correlation of the displacement field created by physiological noise. 9 Following the analogy between this noise-correlation-based field and a time-reversal field, the refocusing obtained by crosscorrelation can be analyzed. The spatial focusing presents a directionality dependence associated with a point body-force radiation pattern.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Near-field effects in Green's function retrieval from cross-correlation of elastic fields: Experimental study with application to elastography

Benech¹,

Brum²,

Catheline

et al. 2013

The Journal of the Acoustical Society of America

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In a lossless system, the causal and acausal Green's function for elastic waves can be retrieved by cross-correlating the elastic field at two positions. This field, composed of converging and diverging waves, is interpreted in the frame of a time-reversal process. In this work, the near-field effects on the spatio-temporal focusing of elastic waves are analyzed through the elastodynamic Green's function. Contrary to the scalar field case, the spatial focusing is not symmetric preserving the directivity pattern of a simple source. One important feature of the spatial asymmetry is its dependency on the Poisson ratio of the solid. Additionally, it is shown that the retrieval of the bulk wave speed values is affected by diffraction. The correction factor depends on the relative direction between the source and the observed field. Experimental verification of the analysis is carried out on the volume of a soft-solid. A low-frequency diffuse-like field is generated by random impacts at the sample's free surface. The displacement field is imaged using ultrasound by a standard speckle tracking technique. One important application of this work is in the estimation of the shear elastic modulus in soft biological tissues, whose quantification can be useful in non-invasive diagnosis of various diseases.

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Section: Experimental Implementationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Near-field effects in Green's function retrieval from cross-correlation of elastic fields: Experimental study with application to elastography

Benech¹,

Brum²,

Catheline

et al. 2013

The Journal of the Acoustical Society of America

View full text Add to dashboard Cite

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“…These methods were first developed in the field of helio-seismology 1 and acoustics, 2 and they have seen growing interest in seismology over the last decade. [3][4][5][6][7][8] Despite remarkable passive imaging results that have been obtained from cross-correlation techniques, 6,9,10 the hypothesis of the homogeneous repartition of sources 11 for exact Green's function reconstruction is rarely achieved. In geophysics, for example, the seismic ambient noise has been shown to be directive 12,13 and most experimental results can suffer from the effects of the nonisotropic illumination of the receiver array.…”

Section: Introductionmentioning

confidence: 99%

A passive inverse filter for Green’s function retrieval

Gallot

Catheline

Roux

et al. 2011

The Journal of the Acoustical Society of America

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Passive methods for the recovery of Green's functions from ambient noise require strong hypotheses, including isotropic distribution of the noise sources. Very often, this distribution is nonisotropic, which introduces bias in the Green's function reconstruction. To minimize this bias, a spatiotemporal inverse filter is proposed. The method is tested on a directive noise field computed from an experimental active seismic data set. The results indicate that the passive inverse filter allows the manipulation of the spatiotemporal degrees of freedom of a complex wave field, and it can efficiently compensate for the noise wavefield directivity.

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“…Living tissue is also full of unexploited vibrations. Their detection with ultrafast ultrasound scanners that can reach thousands of frames per second (5-7) has recently opened up the medical field to correlation techniques and therefore, passive elastography (8). However, ultrasound is not suitable for brain imaging.…”

mentioning

confidence: 99%

Brain palpation from physiological vibrations using MRI

Zorgani

Souchon

Dinh

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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We present a magnetic resonance elastography approach for tissue characterization that is inspired by seismic noise correlation and time reversal. The idea consists of extracting the elasticity from the natural shear waves in living tissues that are caused by cardiac motion, blood pulsatility, and any muscle activity. In contrast to other magnetic resonance elastography techniques, this noise-based approach is, thus, passive and broadband and does not need any synchronization with sources. The experimental demonstration is conducted in a calibrated phantom and in vivo in the brain of two healthy volunteers. Potential applications of this "brain palpation" approach for characterizing brain anomalies and diseases are foreseen.elastography | brain | correlation T he complexity of wave fields can sometimes be an advantage for imaging. Such is the case in multiple scattering or reverberating media, where wave fields contain information about their sources and the medium itself. Turning this wave noise into useful measurements through correlation techniques has provided a breakthrough in a wide variety of domains, which range from seismology (1) to acoustics (2, 3) and electromagnetism (4). Living tissue is also full of unexploited vibrations. Their detection with ultrafast ultrasound scanners that can reach thousands of frames per second (5-7) has recently opened up the medical field to correlation techniques and therefore, passive elastography (8). However, ultrasound is not suitable for brain imaging. MRI can image the brain, but its relatively low acquisition rate of a few frames per second is an issue. Synchronization with the shear-wave source is, thus, necessary (9, 10), which penalizes its potential implementation based on natural shear waves.We describe a magnetic resonance elastography (MRE) -based method that is free from the need for synchronization and any controlled source. This approach extracts information related to the mechanical properties of the soft tissue from hundreds of snapshots of randomly fluctuating shear-wave fields. The key to decrypting the complex field is correlation or similarly but from a physical point of view, time reversal (11, 12). Not only does this wide-band approach maximize the signal-to-noise ratio, as any matched filter would, but it also avoids the Nyquist-Shannon problem that is inherent to slow imaging devices. Indeed, although time information is definitely lost, the spatial information is still present and allows shear-wavelength tomography to be conducted. This wavelength is closely related to the shear elasticity and thus, the intuitive estimation of the stiffness felt by physicians during palpation examination. To start, this concept is shown using MRI in a calibrated elastography phantom under randomly sampled vibrations. Arterial pulsation can produce motion in the brain as high as 1 mm (13); the resulting natural shear-wave field is analyzed through correlation algorithms, and passive brain palpation reconstructions are presented. ResultsPhantom Experiments. As s...

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Passive elastography: shear-wave tomography from physiological-noise correlation in soft tissues

Cited by 90 publications

References 28 publications

Near-field effects in Green's function retrieval from cross-correlation of elastic fields: Experimental study with application to elastography

Near-field effects in Green's function retrieval from cross-correlation of elastic fields: Experimental study with application to elastography

A passive inverse filter for Green’s function retrieval

Brain palpation from physiological vibrations using MRI

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