3-DIMENSIONAL NMR MICROSCOPY OF RAT SPLEEN AND LIVER

Three-dimensional microscopic NMR images of spleen and liver specimens from rats injected with dextran magnetite particles and from controls were obtained at 4.7 T, using a specially designed probe in conjuncti on with a 3D filtered back projection reconstruction algorithm. All of the images were reconstructed as 64(3) arrays with (25 mum)3 isotropi c voxels. With the aid of the MR contrast agent, the red pulp and marg inal zone of the spleen and the portal triad of the liver could be dis tinguished from the surrounding tissue in T2-weighted images. For matu re rat spleen, natural contrast in T2-weighted images was found to dis tinguish the same features. Histological examinations of the tissues w ith and without contrast agent were also performed using an optical mi croscope. Microscopic NMR images, despite their lower resolution, clea rly revealed many features seen in the optical images.