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.