To investigate multimodel MRI exploring the pathophysiology of multiple sclerosis and neuromyelitis optica spectrum disorders.

The investigators use multimodel MRI to evaluate the extent of blood-brain barrier and white matter fiber tracts destruction , iron deposition and cerebral blood flow of associated regions in multiple sclerosis and neuromyelitis optica spectrum disorders using contrast-enhanced magnetic resonance imaging , quantitative susceptibility mapping, diffusion tension imaging, and arterial spin labeling with post labeling delay of 2.0 seconds. Transfer constant volume , magnetic susceptibility, cerebral blood flow and fractional anisotropy(FA) value were measured in lesion and normal appearing white matter.

Patients:

Patients with multiple sclerosis and neuromyelitis optica spectrum disorders were included. clinical characteristics such as disease duration, expanded disability status scale(EDSS) score, age, associated laboratory examination(autoantibodies directed to aquaporin-4 and oligoclonal bands in serum as well as cerebrospinal fluid)were recorded.

Imaging scan were conducted at admission, six months and one year after admission

Imaging protocols:

MRI scan protocols: T2 weighted image, T1 weighted image, Diffusion weighted image(DWI), fluid-attenuated inversion recovery(FLAIR), dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI) , diffusion tension imaging(DTI) ,quantitative susceptibility mapping(QSM) , arterial spin labeling(ASL) with post labeling delay(PLD) of seconds, sagittal CUBE Fluid Attenuation Inversion Recovery (FLAIR) images, sagittal 3-dimensional Fast Spoiled Gradient Echo(3D-FSPGR).

Contrast agent:

Omniscan 0.1mmol/kg, Inject rate：2ml/s

Imaging evaluation:

Transfer constant volume value measured by DCE-MRI indicates the extent of blood-brain barrier destruction.

Magnetic susceptibility manifests iron deposition in lesions and normal appearing white matter.

Diffusion tension imaging demonstrates the extent of white matter fiber tracts destruction.

Arterial spin labeling(ASL) with post labeling delay(PLD)of seconds shows cerebral blood flow in associated regions.

Inclusion Criteria:

1. a diagnosis of neuromyelitis optica spectrum disorders(according to the 2015 revised diagnostic criteria) or relapsing remitting multiple sclerosis(according to the 2010 revised Mcdonald criteria)
2. age between 18 years old and 60 years old(concluding 18 years old and 60 years old)

Exclusion Criteria:

1. common exclusion for MRI such as patients with claustrophobia
2. patients with poor imaging quality（Poor imaging quality mainly defined as the image cannot be applied to future analysis on account of severe motion artifacts appeared in conventional MRI and mistakes in the MRI process by accident factors which cannot to be applied to future analysis）
3. patients with taking amount of antidepressant recently and with alcoholism and other nervous system diseases

patients with multiple sclerosis (according to the 2010 revised Mcdonald criteria) and neuromyelitis optica spectrum disorders (according to the 2015 revised diagnostic criteria)