A Head-to-Head Comparison of High-Resolution Sonography and MRI in Treatment-Naive Chronic Inflammatory Neuropathies (P4.076)

Objective: To establish the relative value of neuro-imaging techniques i.e. high-resolution sonography (HRUS) and magnetic resonance imaging (MRI) of the brachial plexus for the diagnosis of chronic inflammatory demyelinating neuropathy (CIDP) and multifocal motor neuropathy (MMN) in treatment-naive patients. Background: Several previously published case-series and case-control studies have documented the frequentpresence of multifocally enlarged nerves in patients with CIDP and MMN. Interpretation of these studies is complicated by small sample size and considerable heterogeneity of important patient characteristics. The relevance of inclusion of treatment-naive patients was shown by a recent study that showed variability of nerve size over time and in relation to treatment response in patients with CIDP. Methods: We enrolled 40 consecutive, newly diagnosed, treatment-naive patients with CIDP (n= 20) and MMN (n = 20). In addition to all relevant clinical examinations and extensive nerve conduction studies, all patients underwent a standardized MRI protocol of thebrachial plexus to assess enlargement or T2-hyperintensity and high resolution sonography of the median nerve and brachial plexus bilaterally to determine presence of nerve (root) enlargement. Results: We found enlargement of brachial plexus in 14/40 (35[percnt]) and/or T2-hyperintensity in 26/40 (65[percnt]) patients with MRI, and 28/40 (70[percnt]) with HRUS. MRI showed an abnormal brachial plexus in 2/40 (5[percnt]) patients with normal HRUS, whereas sonographic nerve enlargement of brachial plexus and/or median nerve was found in 14/40 (35[percnt]) patients with normal MRI. We found no correlation between age, disease duration or MRC sum-score and nerve size and enlargement or presence of T2-hyperintensity. Conclusions: HRUS and MRI of the brachial plexus are abnormal in 65-70[percnt] of patients with CIDP and MMN. HRUS is a practical bedside tool that is at least as useful as brachial plexus MRI in the diagnostic work-up of patients with suspected chronic inflammatory neuropathies. Disclosure: Dr. Goedee has nothing to disclose. Dr. Van Der Pol has received personal compensation for activities with Baxter as a consultant. Dr. Van Asseldonk has nothing to disclose. Dr. Visser has nothing to disclose. Dr. Van den Berg has received personal compensation for activities with Baxter, Biogen Idec, and Cytokinetics as a consultant.