Magnetic resonance imaging (MRI) is a noninvasive
technique that can be used to obtain tomographic images
of opaque organisms.32,33 In comparison to other imaging
techniques such as X-ray or PET, MRI requires no ionizing
radiation while producing images with high spatial and
temporal resolution, excellent soft tissue contrast, and deep
tissue penetration.32 Images are based on the 1H NMR signal
of water with signal intensities proportional to the relaxation
rates of the nuclear spins. Different concentrations and
microenvironments of water in different tissues result in
image contrast