Cortical thickness and diffusion tensor imaging in patients with neuropsychiatric systemic lupus erythematosus, with normal structure on brain MRI

Objectives Neuropsychiatric systemic lupus erythematosus (NPSLE) is associated with adverse outcomes; however, imaging abnormalities are only detectable by conventional brain magnetic resonance imaging (MRI) in up to 50% of patients. This study investigated the variability in cortical thickness and diffusion tensor imaging (DTI) parameters among patients with NPSLE whose brain morphology appeared normal on conventional MRI. Methods This retrospective study enrolled 27 female patients with NPSLE (median age: 41.0 years, range: 22-63 years) and 34 female healthy controls (median age: 37.0 years, range: 24-55 years). None exhibited evident abnormalities on conventional MRI. Regional volumes, cortical thickness, and DTI parameters, including fractional anisotropy (FA) and mean diffusivity (MD), were compared. Age-adjusted multivariable logistic regression analysis was conducted to detect significant NPSLE-associated differences. Results No significant differences in grey or white matter volume fractions were observed between the groups. However, the NPSLE group demonstrated significant cortical thinning in the right pars opercularis (2.45 vs 2.52 mm, p = 0.007), reduced FA values in the fornix (0.35 vs 0.40, p = 0.001) and left anterior limb of internal capsule (0.50 vs 0.52, p = 0.012), and increased MD in the fornix (1.71 vs 1.48, p = 0.009) and left posterior corona radiata (0.80 vs 0.76, p = 0.005) compared with those of healthy controls. Conclusions Cortical thickness measurements and DTI analyses can be used to detect differential variations in patients with NPSLE who exhibit an otherwise normal brain structure on conventional MRI, indicating the existence of subtle changes despite the absence of obvious macrostructural central nervous system involvement of lupus.