MAGNETIC-RESONANCE-IMAGING, HISTOLOGY, AND X-RAY OF 3 STAGES OF DAMAGE TO THE KNEES OF STR ORT MICE/

RATIONALE AND OBJECTIVES. The authors develop a scoring system for ass essing those features of degeneration of the STR/ORT mouse knee visual izable by magnetic resonance (MR) imaging, and to validate those MR sc ores by comparison with x-ray and histology. METHOD. Magnetic resonanc e imaging, histology, and x-ray have been used in a cross-sectional st udy to visualize the anatomy and pathology of the knees of three pairs of male STR/ORT mice and their approximately age-matched female pairs , A scoring system was developed that distinguished the faster rate of damage of the males from the slower progressive changes seen in the f emales. RESULTS. Changes in the patellar tendon were observed in MR im aging of the 5-month-old male knee, Sagittal images showed other degen erative features such as sclerosis and lass of signal from synovial fl uid after 9 months; osteophytes and degeneration of the tibial plateau were better visualized in the coronal plane, Cysts were poorly correl ated to the progression of the disease, Similar trends were observed f or four features scored in x-rays (sclerosis, joint space narrowing, c ysts, and osteophytes) and cartilage degradation assessed using histol ogy, In contrast, the age-matched females were less affected. CONCLUSI ONS. Magnetic resonance imaging can identify joint degeneration in the knees of male mice, which develops more rapidly than in age-matched f emales, Those observations were validated by radiology and histology.