Agarose and Wax Tissue-Mimicking Phantom for Dynamic Magnetic Resonance Imaging of the Liver

Abstract

Objectives: Polymer phantoms can be used to simulate the properties of tissues or organs such as the liver during magnetic resonance imaging (MRI). Although there are reports of simulated liver phantoms with hepatocellular carcinoma (HCC); no studies have documented the simulating of the typical dynamic pattern. Aim: The present study aimed to investigate properties of developed phantoms with respect to the stability, including chemical, mechanical, electrical, as well as MRI properties (T1- and T2- signal intensities), in addition to simulating HCC in a dynamic way. Methods: In this study, liver parenchyma of size 23 ×18 ×13 cm was simulated using three different agarose-wax samples (agarose at concentrations of 2.5 wt%, 4.5 wt%, and 6.0 wt%) mixed with a fixed wax concentration of 2.6 wt%.. HCC samples were fabricated using polyurethane and glycerol of various diameters (0.5, 1.0, and 2.0 cm). Results: The results showed that the agarose-wax sample with a concentration of 2.5 wt% was the most stable sample among the other samples (P-value, 0.468) in mechanical and T1 and T2 intensities. It was also noted that the sample at the concentration of 4.5 wt% had the closest density value to human liver with a difference of 7.88%. Moreover, the agarose-wax sample at a concentration of 2.5 wt% had the closest compressibility and conductivity values, and T1-relaxation time compared to the human liver. However, the largest changes in relaxation times were observed in the fifth week of all samples (P-value = 0.047). The typical enhancement pattern for a simulated HCC of a minimum size, which can be measured with MRI, was 1.0 cm, using a body coil, and 0.5 cm using a head coil. Conclusions: The chemical, electrical density, compressive strength, density, and MR imaging properties of the phantom were measured and compared to those of the human body.