Abstract
In order to measure the diffusion coefficients the recovery time of static magnetic field was evaluated to be less than 1 ms after turning-off of the gradient pulse at the maximum intensity 30 gauss/cm. Then an NMR method was developed to measure simultaneously the diffusion coefficients of several different kinds of simple liquids. Each liquid sample was kept in a different small container arrayed along one axis. The reading gradient was applied along the axis to encode the location of the samples in the signals. The spin echo pulse sequence was used and a pair of the motion-probing gradient was placed before and after the 180 degree pulse. We could get the diffusion coefficient values of acetone, water, methanol, and DMSO, in order according to larger to smaller values. The diffusion MRI study was conducted on a brain sample isolated from a rat and kept in a formalin solution. The best resolution image was about 0.1 mm resolution with the slice thickness 0.5 mm. On the diffusion-weighted images the spin echo signals were attenuated faster on the water molecules having the larger value of diffusion coefficient, such as those in the formaldehyde solution. It made us possible to obtain the brain images on the sample kept in the solution when the larger motion probing gradients were used. [J Physiol Sci. 2008;58 Suppl:S198]
