[A clinical study on the diagnosis of early rheumatoid arthritis using bone imaging with 99mTc-MDP]

This study aimed to explore the usefulness of 99mTechnetium methylenediphosphonate (99mTc-MDP) bone imaging in diagnosticating rheumatoid arthritis (RA). In 66 patients with RA, 99mTc-MDP whole body bone imaging, feet and hands regional bone imaging and ROI were performed. And from each patient, X-ray film, rheumatoid factor (RF), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were taken for examination. By the use of 99mTc-MDP, abnormal bone images were observed in 55 cases of RA; the total positive rate of incidence (83.3%) was significantly higher than those by use of X-ray (45.5%), RF (51.5%), CRP (63.6%) and ESR (69.7%); the positive rates of imaging with 99mTc-MDP in the 55 cases of RA (divided into 4 groups according to the course of disease; namely, < 1,1-, 5- and >10-year groups) were 75.0%, 88.9%, 92.3% and 100.0% respectively, whereas the positive rates of those year-groups by use of X-ray were 10.7%, 33.3%, 84.6%, 100.0% respectively; comparison of the two methods, showed statistically significant difference: P<0.01 (< 5-year group); P >0.05 (> 5-year group). In 177 joint lesions detected by bone images, 144 lesions (81.4%) were symmetric, and 33 lesions (18.6%) were single. The most frequently detected lesions were at metacarpophalangeal joints or interphalangeal and wrist joints, metatarsophalangeal or ankle joints, and knee joints. We have noticed that 99mTc-MDP bone imaging can elevate the detectability at the early stage of RA, so it is of value for the treatment of RA.