Nuclear magnetic resonance (NMR) tomographic imaging for popliteal cysts in rheumatoid arthritis.

The ability of nuclear magnetic resonance (NMR) tomographic imaging to show a change in proton spin-lattice relaxation time (T1 value) in the joints of patients with rheumatoid arthritis before and after treatment with intra-articular steroid has been assessed. Six patients with seropositive rheumatoid arthritis and clinical evidence of a popliteal cyst were examined by both NMR tomography and arthrography. In all cases the presence of active rheumatoid arthritis was shown by an increase in the T1 values of the synovium of the joints. After arthrography a consistent but small rise in T1 value was noted which fell to below the initial reading after treatment by intra-articular injection of an anti-inflammatory agent. In all cases the presence of the popliteal cyst was clearly shown by both NMR tomography and arthrography. The findings indicate that NMR tomography provides a sensitive method for the demonstration of inflammatory joint disease, popliteal cysts, and possibly for monitoring response to therapy.