Magnetic resonance imaging of the cauda equina in chronic inflammatory demyelinating polyneuropathy

Background. Chronic inflammatory demyelinating polyneuropathy (CIDP) is a treatable disimmune neuropathy, which accurate diagnostics and treatment are essential to improve a long-lasting prognosis and prevent invalidization. In atypical cases and differential diagnosis extra investigations are needed, including neuroimaging.Objective. Evaluating the diagnostic role of the cauda equina magnetic resonance imaging (MRI) in CIDP.Materials and methods. 8 patients with CIDP according to European Federation of Neurological Societies and Peripheral Nerve Society criteria were originally included in the main cohort: 6 patients with definitive CIDP, 1 patient – with possible CIDP; in 1 patient later mixed crioglobulinemia, associated with hepatitis C was later diagnosed. MRI with contrast enhancement of the cauda equina was performed in all primary included patients in the main cohort and in 8 controls with metabolic polyneuropathy. In 12 months MRI was repeated in the main cohort patients.Results. The enlargement of the nerve roots of the cauda equina and nodular hypertrophy was demonstrated in all CIDP patients, and in none of the control subjects. The extensiveness of qualitative changes correlated with disease duration. All CIDP patients with root hypertrophy had gadolinium enhancement and its severity did not correlate with disease activity. Contrast enhancement in roots of the control group patients was explained by the medullary artery phenomenon.Conclusion. MRI of the cauda equina with contrast improves the diagnostic of CIDP, but does not depict the activity of the disease. MRI in CIDP is a promissing technique, requiring further investigation and standardization.