MRI of large intraosseous lesions in patients with inflammatory arthritis

OBJECTIVE. The purpose of our study was to evaluate on MRI the occurrence of large cystlike intraosseous lesions in patients with inflammatory arthritis. SUBJECTS AND METHODS. We prospectively reviewed contrast-enhanced MR images of 128 hands and wrists in 44 patients with clinical presentation of inflammatory arthritis. Large lesions (≥ 1 cm) found on MR images were further evaluated for the presence of a cortical break and intraarticular extension. These data were correlated with clinical and laboratory findings and the duration of arthritis. RESULTS. We found 26 patients with rheumatoid arthritis, seven with psoriatic arthritis, two with systemic lupus erythematosus, one with HIV-associated arthritis, one with mixed connective tissue disorder, one with paraneoplastic-associated arthritis, one with inflammatory bowel disease arthritis, and five patients with early unclassified inflammatory arthritis. Twelve patients had 16 large intraosseous lesions, none of which were detected on available radiographs (availability of radiographs for large erosions was 75%). A cortical break with intraarticular extension of the large lesions was seen in 12 cases. Four lesions were not intraarticular. CONCLUSION. Even large intraosseous lesions may be occult on radiography. MRI is a superior technique for detecting these lesions in the small joints of the hand and wrist in inflammatory arthritis. Although large intraosseous erosions often communicate with joints, we observed four large purely intraosseous enhancing lesions without intraarticular connection. Patients with large erosions have a longer duration of inflammatory arthritis.