NEW YORK (Reuters Health) Jun 24 - In patients with early rheumatoid arthritis (RA), bone marrow edema on MRI predicts erosive progression, according to a report in the July Annals of the Rheumatic Diseases.

This finding is from a study conducted by Dr. E. A. Haavardsholm from University of Oslo, Norway and colleagues, in which they examined the spectrum and severity of MRI findings in patients with RA of less than 1 year's duration, as well as the predictive value of these findings for subsequent development of conventional radiographic damage and MRI erosions.

X-rays, MRI studies, and core measures of disease activity were obtained at the start of the study and 3, 6, 9 and 12 months later. MRI findings reflecting inflammation decreased during the 1 year of follow-up, the authors report, whereas MRI erosion scores and conventional radiographic damage increased slightly.

"The proportion of patients with erosive progression at 1 year was 48% for conventional radiography and 66% for MRI," the authors said.

Bone marrow edema on the baseline MRI study was an independent predictor of erosive progression both on conventional x-rays and on MRI.

"In this study of early RA we found that MRI findings were common and associated with erosive progression," the authors write. They add, "These findings, taken together with results from previous smaller studies, suggest that MRI scans of the dominant wrist may assist the clinicians in their considerations of which patients need early and aggressive treatment to avoid subsequent joint damage."

"MRI bone marrow edema should be recognized as an important prognostic factor in early RA," the researchers conclude.

Ann Rheum Dis 2008;67:794-800.