A Study on Magnetic Nanoparticles Concentration in Shear Wave Dispersion Magnetomotive Ultrasound

There are various elasticity modalities to obtain mechanical properties of human tissue. Measuring these properties are valuable in clinical diagnosis because it can lead to diagnose some diseases such as cancer and liver fibrosis. In recent years, an imaging technique called magneto-motive ultrasound (MMUS) imaging has been introduced as a technique to improve the sensitivity of ultrasound using magnetic nanoparticles (MNPs) as contrast agent. An external alternating magnetic field gradient is applied to induce a displacement in the soft tissue labeled with iron oxide nanoparticles and the resulting displacement in the medium is detected by ultrasound. In this study, a type of MMUS was used which is known as Shear Wave Dispersion Magnetomotive Ultrasound (SDMMUS). This modality, which is a novel elasticity method, estimates viscoelastic properties of a medium labeled with magnetic nanoparticles (Fe3O4) by generating shear waves created via an alternating magnetic field. Here, 2 different gelatin tissue-mimicking phantoms (4% of gelatin concentration) were made, in which including an inclusion of iron oxide nanoparticles with certain concentrations of 1.2% and 0.3%. The lowest possible concentration was 0.3% to observe shear wave (SW) and demonstrate a satisfactory contrast in SDMMUS.