Magnetic resonance imaging of the wrist and finger joints in patients withinflammatory joint diseases

Objective. To study magnetic resonance imaging (MRI) features in the wrist and metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal i nterphalangeal (DIP) joints in 4 patient groups: early rheumatoid arthritis (RA) (< 3 yrs); established RA (> 3 yrs); other arthritis; arthralgia. Methods. MRI was obtained before and after contrast (gadodiamide) injection of the wrist and finger joints in 103 patients and 7 controls. The study i ncluded: (1) 28 patients with disease duration < 3 yrs who fulfilled the Am erican College of Rheumatology (ACR) criteria for RA; (2) 25 patients with RA disease duration > 3 yrs who fulfilled the ACR criteria; (3) 25 patients with reactive arthritis, psoriatic arthritis, or mixed connective tissue d isease; and (4) 25 patients with arthralgia. The following MRI variables we re assessed: number of joints with enhancement after contrast injection, nu mber of joints with joint fluid, and number of bones with edema in the wris t and fingers. The volume of the enhancing synovial membrane after contrast injection in the MCF, PIP, and DIP joints was manually outlined. MR images were scored independently under blinded conditions. Results. Bone marrow edema was found in 68% of the patients with establishe d RA, and the number of bones with edema was significantly higher in patien ts with established RA compared to patients with early RA, other arthritis, and arthralgia (Mann-Whitney p < 0.04). Bone edema was not found in patien ts with arthralgia. There was marked overlap within and between the patient groups. No differences in MRI features were found between patients with ea rly RA and patients with other arthritis. The volumes of the synovial membr ane in the MCP, PIP and DIP joints were significantly higher in patients wi th arthritis compared to patients with arthralgia. Conclusion. Although there was marked overlap between the arthritis patient groups, MRI determined bone marrow edema and synovial membrane volumes pro vided additional information about disease activity and may be used as a ma rker of it. Bone marrow edema appeared with the highest percentage in patie nts with long duration of RA (> 3 yrs) and is probably secondary to changes in inflammatory activity.