Myocardial involvement in systemic lupus erythematosus detected by magnetic resonance imaging.

Myocardial involvement in systemic lupus erythematosus is commonly found at autopsy but seldom recognized clinically or by routine cardiological investigations. As the magnetic resonance relaxation parameter, T1, is altered by changes in tissue cellularity, we carried out magnetic resonance imaging in 10 patients with systemic lupus erythematosus. Five had active systemic lupus erythematosus when assessed using the lupus activity criteria count. The mean (+/- SD) T1 was 319 +/- 12 in normal volunteers and 321 +/- 10 in a second control group with hypertrophic cardiomyopathy. In the group with systemic lupus erythematosus, there was a higher mean value of 336 ms with a wider scatter of individual results (SD +/- 22 ms). In the subgroup of patients with active disease, T1 was significantly higher (349 +/- 24) than in either of the two control groups. In addition, there was an inverse correlation between serum complement and myocardial T1 in patients with systemic lupus erythematosus. Myocardial abnormalities in systemic lupus erythematosus were demonstrated by magnetic resonance imaging even where other non-invasive cardiac investigations were negative. We conclude that T1 calculated from magnetic resonance imaging is often abnormal in systemic lupus erythematosus and probably indicates myocardial involvement.