DTI metrics reflecting microstructural changes of normal appearing deep grey matter in multiple sclerosis

Purpose: To evaluate the role of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in detecting microstructural changes of normal-appearing deep grey matter (NDGM) in multiple sclerosis (MS). Patient and methods: We examined 40 patients with MS and 20 healthy volunteers using DTI to correlate average ADC and FA of the thalami, lentiform and caudate nuclei between the two groups. Receiver operating characteristic analysis was used to test the diagnostic performance of ADC and FA in detecting NDGM involvement in multiple sclerosis. Results: Between the two study groups, there was statistically significant difference of ADC of thalami, lentiform, caudate nuclei, and FA of the thalami (p < .05). No statistically significant difference of FA of lentiform (p=.2) and caudate (p = .06) nuclei. For detection of microstructural changes of NDGM, ADC cut off values were 0.762 Multiplication Sign 10^-3 mm²/s for thalamus (90% sensitivity and 66% specificity), 0.529 Multiplication Sign 10^-3 mm²/s for lentiform (86% sensitivity and 60% specificity) and 0.784 Multiplication Sign 10^-3 mm²/s for caudate nuclei (83% sensitivity and 67% specificity). Conclusion: ADC has better diagnostic performance and is more accurate than FA as a measure to detect microstructural changes of NDGM