Purpose: To determine whether cerebral atrophy in systemic lupus erythematosus is associated with decreased levels of the neuronal marker N-acetyl-aspartic acid.
Methods: Two groups of patients with systemic lupus erythematosus were studied, those with significant atrophy (n = 11) and those without significant atrophy (n = 10), using proton MR spectroscopy on a 1.5-T imaging unit. The solvent-suppressed, short-echo, volume-localized proton spectroscopy technique showed typical brain metabolites, including N-acetylaspartate, creatine/phosphocreatine, and choline-containing compounds.
Results: The N-acetylaspartate-to-creatine/phosphocreatine ratio was smaller in those patients with significant cerebral atrophy (1.68 +/- 0.27) than in those patients with minimal or no atrophy (2.17 +/- .30). The degree of atrophy was negatively correlated with the N-acetylaspartate-to-creatine/phosphocreatine ratio. The choline-to-creatine/phosphocreatine ratio was not significantly altered in systemic lupus erythematosus patients with atrophy.
Conclusion: These data suggest that cerebral atrophy in systemic lupus erythematosus is associated with neuronal dropout (or damage), which results in decreased N-acetylaspartate ratios. A change in choline ratios is not implicated in the biochemical changes associated with cerebral atrophy. Proton MR spectroscopy may be useful in correlating brain metabolites with cerebral structural changes in patients with autoimmune diseases.