Magnetic Resonance Imaging (MRI) of Water Diffusion in 2-Hydroxyethyl Methacrylate (HEMA) Gels

Abstract

ABSTRACTA fundamental study focusing on correlating the local water self-diffusion coefficient to the local free water content in 2-hydroxyethyl methacrylate (HEMA) gels was conducted. HEMA gels were synthesized with different nominal water content (50% to 90%). MRI measurements of local diffusion coefficient distribution and local water content profiles are conducted on a 600 MHz scanner. The local water content is measured via two spin-echo images with sufficiently long repetition time (TR) to eliminate T1-weighting and two values for the echo time (TE) in order to account for T2-weighting. The local diffusion coefficient is determined using a standard pulsed-field gradient spin-echo sequence. The measured local water content and diffusion coefficient data are compared with several single-parameter diffusion models for interstitial diffusion in the hydrogel (Makie-Meares, Stokes-Einstein, Brownian motion around overlapping spheres).