Correlations Between Quantitative MR Imaging Properties and Viscoelastic Material Properties of Agarose Gel

This study determines and assesses correlations between quantitative magnetic resonance imaging (qMRI) parameters (proton density, diffusion, T1 and T2 relaxation) and viscoelastic material properties (storage modulus) for various low concentrations (0.5–3.0 % weight/volume) of agarose gel. MR imaging was done using a 3T (Philips Achieva) scanner. Dynamic mechanical analysis (DMA) was used to characterize the viscoelastic properties of the gels. The repeatability and accuracy of the DMA measurements have some dependence on various geometric sample and measurement parameters. An optimal set of parameters (for compression mode testing) that would produce reliable and repeatable measurements was identified for ranges of sample geometry. Higher concentrations of agarose were associated with higher storage moduli and lower relaxation times, diffusion coefficients, and proton densities. Of the qMRI parameters, T2 relaxation is the most sensitive to changes in concentration.