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Dual Objective Approach Using A Convolutional Neural Network for Magnetic Resonance Elastography
[article]
2018
arXiv
pre-print
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Our network is demonstrated to be effective for generating MRE images that compare well with equivalents from the nonlinear inversion method. ...
Traditionally, nonlinear inversion, direct inversion, or wave estimation methods have been used for reconstructing images from MRE displacement data. ...
Figure 3 shows the reconstructed images from the proposed CNN network for various actuation frequencies compared with estimated µ images from the standard non-linear inversion MRE algorithm. ...
arXiv:1812.00441v1
fatcat:25c7v6hru5fbriolwx3yoefn2y
Frequency-dependent viscoelastic parameters of mouse brain tissue estimated by MR elastography
2011
Physics in Medicine and Biology
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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 ...
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. ...
Dr Mark Conradi supported MR Tx/Rx coil development. Special thanks to colleagues in the Biomedical Magnetic Resonance Laboratory at Washington University for additional assistance. ...
doi:10.1088/0031-9155/56/8/005
pmid:21427486
pmcid:PMC3158029
fatcat:ab4g55lq3vakjeqojlwzc4s6za
Scattering and Diffraction of Elastodynamic Waves in a Concentric Cylindrical Phantom for MR Elastography
2016
IEEE Transactions on Biomedical Engineering
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A customized spin-echo based MR elastography sequence with a sinusoidal motion-sensitizing gradient was used for data acquisition on a 9.4 T Agilent small-animal MR scanner. ...
Petrov et al. investigated complex heterogenous geometries (using tofu and gelatin phantoms) in low-range (< 125 Hz) multi-frequency MRE and a non-linear Schwartz et al. ...
In MR elastography an object is perturbed with harmonic oscillations from a mechanical actuator. ...
doi:10.1109/tbme.2016.2527825
pmid:26886963
pmcid:PMC5097039
fatcat:25vigocoqrawre6lcepbkjk4oe
Viscoelasticity Imaging of Biological Tissues and Single Cells Using Shear Wave Propagation
2021
Frontiers in Physics
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Changes in biomechanical properties of biological soft tissues are often associated with physiological dysfunctions. ...
Finally, current limitations and future directions in shear wave elastography are presented. ...
Uniqueness of Poroelastic and Viscoelastic Nonlinear Inversion MR Elastography at Low Frequencies. ...
doi:10.3389/fphy.2021.666192
fatcat:qvn4pciaxbdbfhynp4spzszrii
Magnetic Resonance Elastography of Rodent Brain
2018
Frontiers in Neurology
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These three steps require an acoustic-frequency mechanical actuator, magnetic resonance imaging acquisition, and a post-processing tool for which no turnkey technology is available. ...
Magnetic resonance elastography (MRE) is a non-invasive imaging technique, using the propagation of mechanical waves as a probe to palpate biological tissues. ...
Different methods have been developed: wavelength estimation method (40, 41) , nonlinear inversion finite-element method (42) , or direct inversion (43, 44) . ...
doi:10.3389/fneur.2018.01010
pmid:30538670
pmcid:PMC6277573
fatcat:zduhdpykobgfvpdy5drxecbfdq
Elasticity reconstruction from experimental MR displacement data: initial experience with an overlapping subzone finite element inversion process
2000
Medical Physics (Lancaster)
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as measured by a phase contrast MR technique. ...
The determination of the elastic property distribution in heterogeneous gel samples with a finite element based reconstruction scheme is considered. ...
Independent measurements of actuator motion using a capacitively coupled displacement probe have demonstrated that the response of the actuators is linear in the applied voltage for a given frequency, ...
doi:10.1118/1.598861
pmid:10659743
fatcat:r5cne5prbbdj5fy2fqfjdd4jyq
Multiresolution MR elastography using nonlinear inversion
2012
Medical Physics (Lancaster)
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Purpose: Nonlinear inversion (NLI) in MR elastography requires discretization of the displacement field for a finite element (FE) solution of the "forward problem", and discretization of the unknown mechanical ...
property field for the iterative solution of the "inverse problem". ...
CONCLUSIONS The multiresolution approach presented provides a flexible framework for NLI MR elastography. ...
doi:10.1118/1.4754649
pmid:23039674
pmcid:PMC3477197
fatcat:oxktyqgzdrgkrivmguuiin573u
Time-harmonic magnetic resonance elastography of the normal feline brain
2010
Journal of Biomechanics
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MR elastography is an imaging technique that can estimate mechanical properties of tissue non-invasively and in vivo. ...
Results fell within the range of values reported in the literature and showed a mean shear modulus across the subject group of 7-8 kPa with all but one animal falling within 5-15 kPa. ...
In effect, MRE performs non-invasive palpation by gently applying low frequency mechanical waves, measuring the resulting time-harmonic tissue motion with a phasesensitive MR sequence, and generating a ...
doi:10.1016/j.jbiomech.2010.06.008
pmid:20655045
pmcid:PMC2963725
fatcat:oo3a7ylxtjfr3bt5b2t2enzzvm
Magnetic resonance elastography (MRE) in cancer: Technique, analysis, and applications
2015
Progress in nuclear magnetic resonance spectroscopy
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Magnetic resonance elastography (MRE) is a noninvasive technique capable of quantifying tissue mechanical properties in vivo. ...
Tissue mechanical properties are significantly altered with the development of cancer. ...
Ultimately, a frequency of 85 Hz was determined to be optimal in balancing low spatial resolution at low frequencies with high attenuation at high frequencies. ...
doi:10.1016/j.pnmrs.2015.06.001
pmid:26592944
pmcid:PMC4660259
fatcat:q7e5tzbfkjdlvcf62s5f2ptpke
An Overview of Elastography-An Emerging Branch of Medical Imaging
2011
Current Medical Imaging Reviews
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Since 2005 however, increasing numbers of mainstream manufacturers have added EI to their ultrasound systems so that today the majority of manufacturers offer some sort of Elastography or tissue stiffness ...
Applying a sinusoidal excitation at low frequencies with a mechanical actuator with a small cylindrical footprint can cause biases due to wave diffraction from the cylindrical source. ...
As such, the elastic modulus measured at low frequency (as in quasi-static elastography) will be predictably lower than the elastic modulus measured with radiation force techniques. ...
doi:10.2174/157340511798038684
pmid:22308105
pmcid:PMC3269947
fatcat:4a3lmhnbpndstc4t4qmkxki25a
Quantitative Compression Optical Coherence Elastography as an Inverse Elasticity Problem
2016
IEEE Journal of Selected Topics in Quantum Electronics
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These methods use a calibration layer with known mechanical properties to sense the stress at the tissue surface, which combined with strain, is used to estimate the tissue's elastic moduli by assuming ...
Recently, novel quantitative elasticity imaging approaches to compression elastography have been developed. ...
Actuation frequency was set below 25 Hz, which was experimentally verified to avoid any detectable wave propagation. ...
doi:10.1109/jstqe.2015.2512597
fatcat:jx335olchrcelnsrqpxch3mmny
MR elastography at 1 Hz of gelatin phantoms using 3D or 4D acquisition
2018
Journal of magnetic resonance (San Diego, Calif. 1997 : Print)
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In-vivo MRE is commonly performed at frequencies of 30-100 Hz using external actuation, however, using cerebro-vascular pulsation at 1 Hz as a form of intrinsic actuation (IA-MRE) eliminates the need for ...
Overall, the hydraulic 1 Hz actuation system when coupled with 4D sequence acquisition produced a fast reliable approach for future IA-MRE phantom evaluation and contrast detail studies needed to benchmark ...
acquired with the low frequency actuation system ...
doi:10.1016/j.jmr.2018.08.012
pmid:30241018
pmcid:PMC6235749
fatcat:g372u5hvufg4zbv6fmhmrw427a
Clinical studies of magnetic resonance elastography from 1995 to 2021: Scientometric and visualization analysis based on CiteSpace
2022
Quantitative Imaging in Medicine and Surgery
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velocities of shear waves, which are then transformed into biological properties via linear or nonlinear inversion algorithms. ...
When low-vibration frequencies are used, the minimum echo time is increased and the images acquired can be prone to a low phase-to-noise ratio, especially in tissues with short T 2 relaxation, such as ...
Actuator ...
doi:10.21037/qims-22-207
fatcat:6j5ztia6lbhgtg33dkp3oqfzzu
Phantom evaluations of nonlinear inversion MR elastography
2018
Physics in Medicine and Biology
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This study evaluated non-linear inversion MRE (NLI-MRE) based on viscoelastic governing equations to determine its sensitivity to small, low contrast inclusions and interface changes in shear storage modulus ...
The NLI-MRE technique detected inclusions as small as 8mm with a stiffness contrast as low as 14%. Storage modulus images also showed an interface edge response distance of 11mm. ...
For human brain with an actuation frequency of 60Hz, L s is approximately 30.5mm (0.64L s ≈ 19.5mm). ...
doi:10.1088/1361-6560/aacb08
pmid:29877194
pmcid:PMC6095192
fatcat:bccn32gvhvdg5dpnmqkfdvxp2i
Nonlinear multiscale regularisation in MR elastography: Towards fine feature mapping
2017
Medical Image Analysis
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Highlights • New Magnetic Resonance Elastography (MRE) software pipeline incorporating wavelet-based denoising and feature-detection techniques • Systematic noise testing with new Finite Element Method ...
|G * | and loss angle φ) that preserve fine-scale information through nonlinear, multi-scale extensions of typical MRE postprocessing techniques. ...
First, the underestimation of the hard target |G * | values by MDEV can be ascribed to loss of low-frequency bandwidth from the inversion of numerically estimated gradients, which have suppressed low-range ...
doi:10.1016/j.media.2016.05.012
pmid:27376240
fatcat:vvtsztxr45eadbv5qlj2nzco6m
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