HIGH-RESOLUTION MR-IMAGING OF JOINT DEGENERATION IN THE KNEE OF THE STR ORT MOUSE/

MR imaging of the knee joints of the mouse at 2.35 T produces an in-pl ane resolution of 35 x 70 mu m and a slice thickness of 600 mu m from the sagittal and coronal planes, in less than 60 min. In normal, five DBA mice, which have no known pathology, the images clearly resolve ma ny joint structures, such as the cruciate ligaments, menisci, and arti culating surfaces of the femur and tibia. Gross pathological changes w ere identified first in excised knees from cadaver mice of the STR/ORT strain. Males of this strain spontaneously exhibit rapid joint degene ration with increasing age compared to females, in which much milder s ymptoms develop more slowly, Thickening of the patellar tendon, displa cement of the patella, deformity, and sclerosis were clearly distingui shable in males compared with females older than 7 mo of age. The same degenerative features were evident in MR images of the knees of the l ive male but not female STR/ORT mice of this age, indicating that it w ould be possible to monitor longitudinally by MR imaging progressive d evelopment of joint changes in this osteoarthritic model.