Abnormal brain diffusivity in patients with neuropsychiatric systemic lupus erythematosus

BACKGROUND AND PURPOSE: Neuroimaging techniques have increased our knowledge of the pathogenesis of neuropsychiatric systemic lupus erythematosus (NPSLE) and have been useful in supporting the diagnosis. Nevertheless, new imaging techniques are needed to unravel the exact pathogenesis and to provide diagnostic criteria for NPSLE. In this preliminary study, we investigated whether diffusion-weighted imaging (DWI) can depict cerebral abnormalities in patients with a history of NPSLE, and we assessed whether apparent diffusion coefficient (ADC) histograms in these patients differ from those of healthy control subjects. METHODS: Eleven female patients with a history of NPSLE (mean age [+/- SD], 35 years +/- 9) and 10 healthy control subjects (eight female, two male; mean age, 37 years +/- 16) underwent DWI. DWI and ADC images were assessed by means of visual inspection, and histograms were composed from the ADC images. From these, we derived a variety of parameters that quantitatively reflect the diffusivity of brain parenchyma. RESULTS: Visual inspection of ADC images and DWIs did not reveal any abnormalities in either patients with NPSLE or control subjects. In contrast, ADC histograms of the NPSLE group were, on average, significantly lower and broader, with a higher mean ADC value. CONCLUSION: The data suggest an increased general diffusivity in brain parenchyma of patients with NPSLE, probably based on loss of tissue integrity. In addition to increasing our battery of highly wanted diagnostic tools and our understanding of the pathogenesis of NPSLE, the present method seems to be useful in quantifying the disease burden, enabling monitoring in treatment trials and the study of disease progression.