Effect of glucocorticoid therapy on brain white matter microstructure in thyroid-associated ophthalmopathy: a longitudinal diffusion kurtosis imaging study.

To investigate the changes in brain white matter microstructure in patients with thyroid-associated ophthalmopathy (TAO) before and after glucocorticoid therapy using diffusion kurtosis imaging (DKI) with tract-based spatial statistics (TBSS) method. Twenty TAO patients and 20 healthy controls were enrolled for clinical and magnetic resonance imaging (MRI) examinations. All patients had intravenous glucocorticoid therapy, followed by MRI scans and clinical assessments three months after the treatment ended. TBSS was used to evaluate the mean kurtosis (MK), axial kurtosis (AK), radial kurtosis (RK), kurtosis fractional anisotropy, fractional anisotropy (FA) and mean diffusion of brain white matter. At baseline, TAO patients showed significantly decreased MK, AK, RK and FA in extensive white matter tracts compared to controls. After therapy, increased MK and AK were observed in comparison to the pre-therapy cohort. However, post-therapy TAO patients still exhibited reduced RK in partial white matter tracts compared to controls. RK values in left posterior thalamic radiation (PTR) showed a negative correlation with CAS in pre-therapy TAO patients. Meanwhile, RK values in left PTR were positively correlated with quality of life scores for visual functioning, and RK values in left anterior corona radiata were negatively correlated with anxiety scores in post-therapy TAO patients. Our findings suggested that TAO could lead to white matter deficits in the visual, cognitive, and emotional brain areas, which were partially restored after treatment.