Objective: This study addressed the following questions: How does 99mTc-IgG scintigraphy compare to physical examination in the detection of synovitis as determined histologically, and is 99mTc-IgG scintigraphy a sensitive detector of histologically documented synovitis activity in the absence of clinically detectable knee joint swelling?
Methods: The results of measuring synovitis activity by physical examination and by scintigraphy with technetium-99m labelled polyclonal human immunoglobulin G (99mTc-IgG) were compared with the results of histological examination of synovial biopsies taken from the knee joints of patients with rheumatoid arthritis (n = 21), osteoarthritis (n = 9) and various other rheumatic diseases (n = 10).
Results: The sensitivity of 99mTc-IgG scintigraphy in detecting synovitis activity, as determined histologically (85%), was higher than the sensitivity of joint swelling (65%). In the absence of clinically detectable knee joint swelling the sensitivity of 99mTc-IgG scintigraphy was 83%.
Conclusion: This study shows that 99mTc-IgG scintigraphy is a more sensitive method than physical examination in detecting histologically documented synovitis activity.