Role of thalamic diffusion for disease differentiation between multiple sclerosis and ischemic cerebral small vessel disease.

INTRODUCTION: Cerebral small vessel disease (CSVD) and multiple sclerosis (MS) both harbor multiple, T2-hyperintense white matter lesions on conventional magnetic resonance imaging (MRI).We aimed to determine the microstructural changes via diffusion-weighted imaging (DWI) in normal appearing thalami. We hypothesized that the apparent diffusion coefficient (ADC) values would be different in CSVD and MS, since the extent of arterial involvement is different in these two diseases.
METHODS: DWI was performed for 50 patients with CSVD and 35 patients with MS along with gender- and age-matched controls whose conventional MRI revealed normal findings. DWI was done with 1.5 Tesla MR devices using echo planar imaging (EPI) for b = 0, 1000 s/mm(2). ADC values were obtained from the thalami which appeared normal on T2-weighted and FLAIR images. Standard oval regions of interest (ROIs) of 0.5 cm(2) which were oriented parallel to the long axis of the thalamus were used for this purpose.
RESULTS: The mean ADC value of the thalamus was (0.99 ± 0.16) × 10(-3) mm(2)/s in patients with CSVD, whereas the mean ADC value was (0.78 ± 0.06) × 10(-3) mm(2)/s in the control group. The mean ADC value was significantly higher in patients with CSVD compared to the controls (p < 0.001). The mean ADC values of the thalamus were (0.78 ± 0.08) × 10(-3) mm(2)/s in MS patients, and (0.75 ± 0.08) × 10(-3) mm(2)/s in the control group, which are not significantly different (p > 0.05).
CONCLUSION: Our study revealed a difference in the diffusion of the thalami between CSVD and MS. DWI may aid in the radiological disease differentiation.