Search results for: Mostafa Fatemi

Items from 1 to 20 out of 58 results

article

Shear wave elastography of the median nerve: A mechanical study

Verena J.M.M. Schrier, Jason Lin, Adriana Gregory, Andrew R. Thoreson, more

Background Shear wave elastography (SWE) shows promise in peripheral neuropathy evaluation but has potential limitations due to tissue size and heterogeneity. We tested SWE sensitivity to elasticity change and the effect of probe position in a median nerve cadaver model. Methods Ten specimens were used to measure median nerve elasticity under increasing loads using SWE and indentation. Measurements...

article

Ultrasound Characterization of Bone Demineralization Using a Support Vector Machine

Max Denis, Leighton Wan, Mostafa Fatemi, Azra Alizad

Ultrasound in Medicine & Biology > 2018 > 44 > 3 > 714-725

We propose an ultrasound-guided remote measurement technique, utilizing an acoustic radiation force beam as our excitation source and a receiving hydrophone, to assess non-invasively a bone's mechanical properties. Features, such as velocity, were extracted from the acoustic pressure received from the bone surface. The typical velocity of an intact bone (3540 m/s) was higher in comparison to that...

chapter

Acoustoelasticity modeling of bladder tissue nonlinearity: Ex vivo study

Mahdi Bayat, Aprana Singh, Jeremy Webb, Viksit Kumar, more

2017 IEEE International Ultrasonics Symposium (IUS) > 1 - 4

2017 IEEE International Ultrasonics Symposium (IUS)

A method for measurement of the bladder wall nonlinear elasticity is presented. The method is based on acoustoelasticity modeling of the bladder tissue modulus of elasticity changes at different volumetric loading levels. At each loading volume, tissue strain is obtained from the real-time images. Using acoustic radiation force, a transient Lamb wave is excited on the bladder wall and shear elasticity...

chapter

Acoustoelasticity modeling of bladder tissue nonlinearity: Ex vivo study

Mahdi Bayat, Aparna Singh, Jeremy Webb, Viksit Kumar, more

2017 IEEE International Ultrasonics Symposium (IUS) > 1

2017 IEEE International Ultrasonics Symposium (IUS)

Bladder is a complex organ and its proper function is closely tied to the mechanobiology of its multi-layer wall. Characterization of the bladder wall mechanical properties is crucial in diagnosis of diseases that can lead to lower tract infection and incontinence. Ultrasound bladder vibrometry has emerged as a noninvasive method for characterization of the bladder tissue elasticity using Lamb wave...

chapter

Viscoelastic properties of breast masses: A frequency dispersion analysis using acoustic radiation force

Viksit Kumar, Mahdi Bayat, Max Denis, Adriana Gregory, more

2017 IEEE International Ultrasonics Symposium (IUS) > 1

2017 IEEE International Ultrasonics Symposium (IUS)

Elasticity values reported by shear wave elastography techniques for Breast tissue/mass are a combination of elasticity and viscosity at the frequency with peak shear wave energy; thus, resulting in overestimation of tissue elasticity. To better estimate shear elasticity and to understand the role of shear viscosity in suspicious breast masses at different frequencies, the frequency dispersion of...

chapter

Background-free visualization of microvasculature networks

Mahdi Bayat, Mostafa Fatemi, Azra Alizad

2017 IEEE International Ultrasonics Symposium (IUS) > 1

2017 IEEE International Ultrasonics Symposium (IUS)

Recent studies have shown the ability of concurrent spatial-temporal processing methods such as singular value decomposition (SVD) filtering in visualization of the small vessels without using any type of contrast agents. The vessel images resulting from SVD filtering suffer from local and global residual background that limit the visibility of the entire vessel networks within a fixed dynamic range...

chapter

A study of synthetic aperture focusing using plane waves to provide wider field of view ultrasound imaging without side-lobe artifacts due to the use of sampling angle in transmitting inclined plane waves

Bae-Hyung Kim, Azra Alizad, Mostafa Fatemi

2017 IEEE International Ultrasonics Symposium (IUS) > 1

2017 IEEE International Ultrasonics Symposium (IUS)

Synthetic aperture focusing based on planar waves also known as coherent plane wave compounding (CPWC) was introduced to reduce the diffraction spreading effect of ultrasound at depths (Song et al. US Patent 6736780, 2004). CPWC has been widely used in shear wave elasticity imaging due to its capability of ultrafast frame rate (Montaldo, et al. IEEE TUFFC, vol. 56, 2009). However, CPWC based on unfocused...

article

Acoustically Active Catheter for Intracardiac Navigation by Color Doppler Ultrasonography

Minako Katayama, David Zarbatany, Stephen S. Cha, Mostafa Fatemi, more

Ultrasound in Medicine & Biology > 2017 > 43 > 9 > 1888-1896

Navigation of intracardiac catheters by echocardiography is challenging because of the fundamental limitations of B-mode ultrasonography. We describe a catheter fitted with a piezoelectric crystal, which vibrates and produces an instantaneous marker in color flow Doppler scans. The navigation learning curve was explored first in six pigs. Accuracy and precision of targeting with the navigation marker...

article

Automated Compression Device for Viscoelasticity Imaging

Alireza Nabavizadeh, Randall R. Kinnick, Mahdi Bayat, Carolina Amador, more

IEEE Transactions on Biomedical Engineering > 2017 > 64 > 7 > 1535 - 1546

Noninvasive measurement of tissue viscoelastic properties is gaining more attention for screening and diagnostic purposes. Recently, measuring dynamic response of tissue under a constant force has been studied for estimation of tissue viscoelastic properties in terms of retardation times. The essential part of such a test is an instrument that is capable of creating a controlled axial force and is...

article

Fully Automated and Robust Tracking of Transient Waves in Structured Anatomies Using Dynamic Programming

Zeynettin Akkus, Mahdi Bayat, Mathew Cheong, Kumar Viksit, more

Ultrasound in Medicine & Biology > 2016 > 42 > 10 > 2504-2512

Tissue stiffness is often linked to underlying pathology and can be quantified by measuring the mechanical transient transverse wave speed (TWS) within the medium. Time-of-flight methods based on correlation of the transient signals or tracking of peaks have been used to quantify the TWS from displacement maps obtained with ultrasound pulse-echo techniques. However, it is challenging to apply these...

chapter

Ultrasound Stimulated Vibro-acoustography

James F. Greenleaf, Mostafa Fatemi, Marek Belohlavek

Lecture Notes in Computer Science > Computer Vision and Mathematical Methods in Medical and Biomedical Image Analysis > Acquisition Techniques > 1-10

Vibro-acoustography is a method of imaging and measurement that uses ultrasound to produce radiation force to vibrate objects. The radiation force is concentrated laterally by focusing the ultrasound beam. The radiation force is limited in depth by intersecting two beams at different frequencies so that there is interference between the beams at the difference frequency only at their intersection...

chapter

Imaging the Viscoelastic Properties of Tissue

Mostafa Fatemi, James F. Greenleaf

Topics in Applied Physics > Imaging of Complex Media with Acoustic and Seismic Waves > 257-276

Elasticity and viscosity of soft tissues are often related to pathology. These parameters, along with other mechanical parameters, determine the dynamic response of tissue to a force. Tissue mechanical response, therefore, may be used for diagnosis. Measuring and imaging of the mechanical properties of tissues is the aim of a class of techniques generally called elasticity imaging or elastography...

chapter

Vibro-Acoustography of Arteries

Cristina Pislaru, James F. Greenleaf, Birgit Kantor, Mostafa Fatemi

Atherosclerosis Disease Management > Molecular and Emerging Technologies > 679-698

Vibro-acoustography can reconstruct a map of the object by measuring the acoustic field resulting from object vibration at a specified low frequency (low kilohertz range). This method has been successfully utilized to image arterial calcifications in vitro and in vivo. Recent achievements in transducer technology and software implementation in existing commercial ultrasound machines should facilitate...

chapter

How calcifications affect shear wave speed estimations? An experimental study

Adriana Gregory, Qiang Bo, Mahdi Bayat, Max Denis, more

2015 IEEE International Ultrasonics Symposium (IUS) > 1 - 4

2015 IEEE International Ultrasonics Symposium (IUS)

In this study, comb-push ultrasound shear elastography was the method used to investigate the effect of calcifications on shear wave elastography estimates. The study was divided in two parts. The first part included a finite element method (FEM) simulation to observe closely the effect of calcifications on shear-wave elastography. The second part involved two phantom experiments to investigate the...

chapter

Viscoelastic tissue mimicking phantom validation study with shear wave elasticity imaging and viscoelastic spectroscopy

Carolina Amador, Randall R. Kinnick, Matthew W. Urban, Mostafa Fatemi, more

2015 IEEE International Ultrasonics Symposium (IUS) > 1 - 4

2015 IEEE International Ultrasonics Symposium (IUS)

Acoustic radiation force-based shear wave elasticity (SWE) methods are used to characterize soft tissue pathologies by quantifying tissue viscoelastic (VE) properties. To adequately evaluate SWE methods measurements of VE properties, it is important to characterize VE properties of tissue mimicking phantoms with an independent method. In this study a VE tissue mimicking phantom was developed and its...

chapter

Pixel-based ultrasound image reconstruction: Impact of grid size on signal frequency content

Mahdi Bayat, Alireza Nabavizadeh, Azra Alizad, Mostafa Fatemi

2015 IEEE International Ultrasonics Symposium (IUS) > 1 - 3

2015 IEEE International Ultrasonics Symposium (IUS)

The effect of grid size on the frequency content of the pixel-based image reconstruction algorithms is discussed. It is shown that coarse grid sizes result in simultaneous decimation and down conversion of the axial data. Results of simulations and phantom studies are presented which show the amount of decimation and predicted frequency shifts. The effect of this frequency shift and down-sampling...

chapter

Ultrasound radiation force noninvasive bone assessment

Leighton Wan, Mathew Cheong, Max Denis, Mostafa Fatemi, more

2015 IEEE International Ultrasonics Symposium (IUS) > 1 - 4

2015 IEEE International Ultrasonics Symposium (IUS)

In this work, a novel ultrasound-guided remote measurement technique is proposed for bone quality assessment. The technique utilizes an acoustic radiation force (ARF) excitation source to generate vibrational waves from the bone, and the ensuing radiating acoustic pressure is captured for analysis. Of particular interest, are extracting acoustic features related to the bone mechanical properties....

chapter

An experimental phantom study on the effect of calcifications on ultrasound shear wave elastography

Adriana Gregory, Mahdi Bayat, Max Denis, Mohammad Mehrmohammadi, more

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) > 3843 - 3846

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

In this study, we investigated the effects of single macrocalcifications and groups of microcalcifications on shear wave elastography. Supersonic shear imaging (SSI) and comb-push ultrasound shear elastography (CUSE) were performed on three sets of phantoms to investigate how calcifications of different sizes and distributions influence measured elasticity. Our results demonstrate that the presence...

article

Quantifying vitamin K-dependent holoprotein compaction caused by differential γ-carboxylation using high-pressure size exclusion chromatography

Nicholas C. Vanderslice, Amanda S. Messer, Kanagasabai Vadivel, S. Paul Bajaj, more

Analytical Biochemistry > 2015 > 479 > Complete > 6-14

This study uses high-pressure size exclusion chromatography (HPSEC) to quantify divalent metal ion (X ²⁺ )-induced compaction found in vitamin K-dependent (VKD) proteins. Multiple X ²⁺ binding sites formed by the presence of up to 12 γ-carboxyglutamic acid (Gla) residues are present in plasma-derived FIX (pd-FIX) and recombinant FIX (r-FIX). Analytical ultracentrifugation (AUC) was...

article

2089097 Effect of Benign Calcifications Of Breast Masses On Shear Wave Elastography

Adriana Gregory, Mohammad Mehrmohammadi, Max Denis, Mahdi Bayat, more

Ultrasound in Medicine & Biology > 2015 > 41 > 4 Supplement > S143

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INFONA - science communication portal

Search results for: Mostafa Fatemi

Shear wave elastography of the median nerve: A mechanical study

Ultrasound Characterization of Bone Demineralization Using a Support Vector Machine

Acoustoelasticity modeling of bladder tissue nonlinearity: Ex vivo study

Acoustoelasticity modeling of bladder tissue nonlinearity: Ex vivo study

Viscoelastic properties of breast masses: A frequency dispersion analysis using acoustic radiation force

Background-free visualization of microvasculature networks

A study of synthetic aperture focusing using plane waves to provide wider field of view ultrasound imaging without side-lobe artifacts due to the use of sampling angle in transmitting inclined plane waves

Acoustically Active Catheter for Intracardiac Navigation by Color Doppler Ultrasonography

Automated Compression Device for Viscoelasticity Imaging

Fully Automated and Robust Tracking of Transient Waves in Structured Anatomies Using Dynamic Programming

Ultrasound Stimulated Vibro-acoustography

Imaging the Viscoelastic Properties of Tissue

Vibro-Acoustography of Arteries

How calcifications affect shear wave speed estimations? An experimental study

Viscoelastic tissue mimicking phantom validation study with shear wave elasticity imaging and viscoelastic spectroscopy

Pixel-based ultrasound image reconstruction: Impact of grid size on signal frequency content

Ultrasound radiation force noninvasive bone assessment

An experimental phantom study on the effect of calcifications on ultrasound shear wave elastography

Quantifying vitamin K-dependent holoprotein compaction caused by differential γ-carboxylation using high-pressure size exclusion chromatography

2089097 Effect of Benign Calcifications Of Breast Masses On Shear Wave Elastography

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