Diffusion Tensor Imaging in Chronic Inflammatory Demyelinating Polyneuropathy (PIDC)

The main purpose of this study is to assess the clinical feasibility of diffusion tensor imaging (DTI) for the diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). For thar purpose, investigator will compare, fractional anisotropy (FA) obtained by diffusion tensor imaging (DTI) MRI 3T on brachial plexus and cervical spinal nerve roots between patients with defined Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP), according to the EFNS 2010 criteria, and healthy controls. The secondary outcomes will be to compare DTI parameters (FA, ADC or Apparent Diffusion Coefficient) between CIDP patients, healthy volunteers, and patients with Charcot Marie Tooth disease type 1a (CMT1a) and MRI morphological parameters (T1, STIR) between these groups. Moreover, investigator will investigate the possible relationship between MRI parameters, clinical indices, and electrophysiological measure.

Investigator will prospectively enroll 15 patients with CIDP followed in the Neurology Department of Clermont Ferrand University Hospital, who satisfy the Joint Task Force of the EFNS and PNS definite CIDP criteria. Two control groups will be studied in parallel, including 15 healthy volunteers on one side, and 15 patients with CMT-1A on the other side (proven by genetic testing). Using a 3-T magnetic resonance imaging scanner, we will obtain DTI scans of brachial plexus of these 3 groups, prepare fractional anisotropy (FA) maps, and compare these values between groups. Investigator will evaluate MRI imaging findings too (coronal STIR, T1-weighted images,and DWIs). MRI studies will be reviewed independently by two neuroradiologists, blinded to clinical informations. In all patients with CIDP, investigator will also performs clinical evaluation and electroneuromyography. Correlation between FA values clinical indices will be examined.