NONINVASIVE 3D MR MICROSCOPY AS A TOOL IN PHARMACOLOGICAL RESEARCH - APPLICATION TO A MODEL OF RHEUMATOID-ARTHRITIS

Magnetic resonance microscopy (MRM) was applied to noninvasively image skeletal structures in the hindpaw of the live rat to characterize th e progression of a heterologous type II collagen-induced arthritic pro cess. Using a resonator, with optimized filling factor, three-dimensio nal (3D) gradient-echo images with voxel dimensions of 94 x 81 x 60 mu m(3) were acquired in 54.6 min. Three-dimensional MRM reduces the sli ce positioning problem, which is critical in longitudinal studies. Mor eover, due to the much smaller slice thickness of images derived from 3D data sets, partial volume effects are less pronounced than in corre sponding 2D images. Distinct pathomorphological changes associated wit h the collagen-induced arthritic process (e.g., increase of metatarsop halangeal joint space, and bone and cartilage erosion) could thus be a nalyzed under in vivo conditions.