Microwave thermography as a noninvasive assessment of disease activity in inflammatory arthritis.

Microwave thermography is the technique of measuring natural thermal radiation from body tissues of clinical interest. It is safe, requires no control of environmental conditions and exposes the patient to no ionising radiation. In this study, we found that microwave thermography of the knee joints showed weak correlation with some global parameters of disease activity. Bed rest alone for three days had no significant effect on microwave thermographic index (MTI). Intra-articular steroid injection, however, was associated with a marked fall in MTI both in the injected knee and the contra-lateral knee. We conclude that microwave thermography can measure inflammatory activity in the knee joints of patients with inflammatory arthritis and can respond to clinical change brought about by major treatment intervention.