DEGENERATIVE JOINT DISEASE IN THE GUINEA-PIG - USE OF MAGNETIC-RESONANCE-IMAGING TO MONITOR PROGRESSION OF BONE PATHOLOGY

Objective, The suitability of magnetic resonance imaging (MRI) for ser ial monitoring of bone pathology in the guinea pig stifle joint, an in vivo model of osteoarthritis, was investigated, Methods. MR images we re compared with histologic features and radiographs of 1-mm-thick sec tions to determine the MR correlates of the bone changes. Ten guinea p igs were then imaged on 7 occasions over the first year of life, enabl ing serial measurements of subchondral bone thickness, subchondral pse udocysts, and osteophytes. Results, The signal intensity of trabecular bone in MR images accurately reflected the degree of osteopenia and t rabecular thinning noted around the cruciate ligament insertions, The extent of subchondral sclerosis and the development of marginal osteop hytes were also accurately represented, Serial observations revealed t hat MRI can detect highly significant progression of lytic bone lesion s, subchondral sclerosis, and osteophyte size over periods of 6 weeks, Conclusion, MRI is not only a reliable technique for the assessment o f bone pathology but is also a useful tool for monitoring the progress ion of bone damage in osteoarthritis.