A Preliminary Ultrasound Elastography Study On Ferumoxytol Containing Agarose Phantom

Ultrasound imaging can consist of real-time images and is a safe, low-cost and mobile method in radiology. Ultrasound-based elastography has emerged as a very useful technique for characterizing the acoustic and mechanical properties of living soft tissues. Tissue mimicking phantoms have a crucial role in the development, validation and exploitation of elastography application. In this study, we introduce the working principles of ultrasound elastography and provide information for tissue-mimicking phantom materials; in particular, we discuss how the ultrasound-based elastography imaging process changes and occurs at different concentrations of ferumoxytol and agar. Samples that mimic the tissue were prepared by placing a 5cm and 10cm high silicon ball in different ferumoxytol concentrations, containing different amounts of agar. Agar concentrations were determined as 1% and 1.75% (w/v) (g/100ml), and ferumoxytol concentrations were determined as 0.01 mM, 0.1 mM and 1 mM. In addition, a control group without ferumoxytol at the same agar concentration was prepared for comparison with samples containing ferumoxytol. All prepared samples were made with the LOGIQ E9 (GE) device using a linear probe (9L-D, GE) with a bandwidth of 2-8 MHz. Using standard settings for shear wave elastography, scans were performed parallel to the cylinder axis, and the elastic modulus and shear wave velocity were measured with the 2D-SWE setting. The average and standard deviation three measurements of the elastic modulus and shear wave velocities were obtained for the samples. The best results were obtained at a height of 5 cm. The results indicated that the mechanical properties increased with the concentration of agarose hydrogel and ferumoxytol, declining after 5 mM ferumoxytol concnetration. Studies on the development of the phantom are carried on with its standardization.