Shear wave Vibro Magneto Acoustography for measuring tissue mimicking phantom elasticity and viscosity

Abstract

Estimating the rheological properties of soft tissues is a useful procedure to identify and evaluate pathologies in medical diagnosis. Quantification of soft tissue viscoelasticity can be achieved by generating and tracking shear wave propagation. Many ultrasound-based techniques have been used to evaluate the induced shear wave. The viscosity and elasticity can be measured by shear wave dispersion. The Magneto Motive Ultrasound induces motion within magnetically labeled tissue. This paper describes the Shear wave Dispersion Vibro Magneto Acoustography (SDVMA) technique for analysis and quantifying the viscoelasticity through shear wave propagation in gelatin phantoms labeled with ferromagnetic nanoparticles. Phantoms were excited applying an external magnetic field gradient and the movements induced in the internal phantom structure due to the interaction of the field with the particles were obtained through pulse-echo equipment ultrasound. The movement information were processed to get values of elasticity and viscosity of the medium.

A magneto-motive ultrasound platform designed for pre-clinical and clinical applications

“…A continuous-time harmonic magnetic field with frequency in order of few Hertz, or a burst of magnetic field pulses, usually excites the magnetic nanoparticles (Mehrmohammadi et al, 2011c). Using this technique researchers have also investigated MMUS to evaluate the viscoelasticity of soft tissues by tracking the shear waves induced by motion of the magnetic nanoparticles (Almeida et al, 2014;Pavan et al, 2012), a method known as shear-wave dispersion magneto-motive ultrasound (SDMMUS) (Almeida et al, 2014). The velocity and attenuation of the shear waves can be analyzed to obtain the elasticity and viscosity of the medium (Zhao et al, 2010).…”

Nanopartículas de magnetita dopadas com zinco para fins teranósticos: magnetoacustografia e hipertermia magnética

“…This timevariant magnetization induces a time-variant voltage inductively coupled pickup coil to generate the images. Finally, magnetomotive ultrasound (MMUS) imaging [44] is a recent radiation-free modality to acquire molecular images [45], obtain viscoelastic properties [46,47], and also to localize magnetic nanoparticles within tissues [48]. Ultrasound is noninvasive, cost effective, portable, and deep penetrating; therefore, being the most widely used medical imaging modality; however, relatively low contrast has limited it to be considered as a molecular imaging technique.…”

Multifunctional nanoparticles for ultrasound-guided theranostic application

“…MMUS imaging, a combination of magnetism and ultrasound, is proposed to overcome the poor contrast of stand-alone ultrasound imaging for the localization of MNPs [10] . This technique is one of the recent imaging modalities that benefits from superparamagnetic NPs as contrast agents to visualize molecular and cellular levels through ultrasound imaging while providing viscoelastic properties within the tissue filled with MNPs [79,80] . This approach applies an external time-varying magnetic field to move a magnetically labeled tissue.…”