Abstract
The purpose of this study is to determine if MR images detect morphological changes in the early stages of osteoarthritis. A total of 11 Japanese white rabbits were used as an experi mental model of osteoarthritis, and sectioning of the anterior cruciate ligament was performed. At 1, 3, 6 and 24 months after operation we performed MR imaging under general anesthesia, and then the animals were sacrificed. Finally we examined the sections from each specimen by gross and histological observation. Until three months after operation there were no signal changes in the MR images. Histologically, however, partial-thickness chondral lesions were detected. At 6 months after operation, signal intensity on Ti and T2- weighted spin-echo images was found to be decreased in subchondral areas. These changes indicated early stages of osteoarthritis. The changes were confirmed by histological observation as indicating full-thick-ness chondral defects. At 24 months after operation osteoarthritis was manifested on standard radiographs. MR imaging is a useful tool for detecting osteochondral lesions in the early stages of osteoarthritis.
