Unfertilized chicken eggs as a biological phantom for prostate imaging using magnetic resonance elastography and diffusion-weighted imaging.

Abstract

Magnetic resonance elastography (MRE) allows noninvasive measurement of tissue viscoelasticity and is increasingly applied to characterize soft tissue biomechanics. This study investigates unfertilized chicken eggs as a biologically significant and cost-effective prostate phantom for combined MRE and diffusion-weighted imaging (DWI). Eggs were measured in two thermal states (soft-boiled and hard-boiled) to systematically alter the protein network structure and thus the mechanical properties of the phantom. All specimens were embedded in agarose gel and scanned using a 3T clinical MRI scanner equipped with multifrequency MRE and DWI. Quantitative parameters including shear wave speed (SWS), mechanical phase angle (φ), and apparent diffusion coefficient (ADC) as surrogates for stiffness, fluidity and water diffusivity, respectively, were analyzed in distinct anatomic compartments (yolk, egg white and germinal disc). Across both thermal states, egg white consistently demonstrated significantly higher values for SWS (medians ranging from 2.56 to 3.50 m/s), φ (0.85-0.86 rad), and ADC (1745.7-1529.1 μm2/s) compared to yolk (SWS: 1.25-1.44 m/s; φ: 0.63-0.67 rad; ADC: 278.8-214.8 μm2/s; all p < 0.01). Thermal processing induced biophysical parameter changes but did not eliminate the overall compartmental contrast. Test-retest reproducibility was variable, ranging from poor to excellent across parameters and compartments. In conclusion, unfertilized chicken eggs may represent a stable and structurally heterogeneous biological phantom for MRE with consistent compartmental differentiation. The consistent contrast between yolk and egg white across different thermal states highlights their potential as a simplified two-compartment model for elastography-based imaging and methodological development.