PACTRIMS 2017

Abstract

Nonconventional imaging techniques are more specific for pathological changes than conventional MRI and may provide insight into the pathogenic processes in MS and NMOSD. These techniques include proton MR spectroscopy, diffusion tensor imaging, magnetization transfer imaging, quantitative MR volumetry, and ultrahigh-field strength MRI. The number of studies comparing MS to NMOSD is limited, and findings often did not include the information about AQP4-Ab positivity. Overall, the application of these techniques to patient studies has demonstrated that tissue damage in MS occurs within lesions and is widespread outside lesions. In NMOSD, tissue microstructural damage, as detected by nonconventional techniques, may be seen in the normal-appearing tissue outside lesions, but it seems to be secondary to the prevalent damage occurring in the optic nerve and cortico-spinal tract. Tissue destruction in NMOSD lesions seems to be greater than that occurring in MS lesions. In NMOSD, the tissue degeneration in the white matter is greater than that in the grey matter. NMO patients seem to show predominant spinal cord atrophy, whilst MS patients show greater whole brain atrophy and grey matter atrophy, especially in the progressive phase of the disease. A recent study has suggested that cord atrophy in NMOSD may occur even in the absence of spinal cord lesions. Deep grey matter atrophy and thalamic microstructural changes appear to be more extensive in MS than NMOSD. A few studies using advanced imaging have suggested that, in both diseases, there are correlations between tissue damage, as detected by imaging measures, including atrophy and diffusion abnormalities, and physical and cognitive disability.