The combination of MR neurography at 3T and 7T for the assessment of nerve damage in peripheral neuropathies

Motivation: To assess the size of proximal nerve fascicles in patients with polyneuropathies and to determine whether fascicle size has an impact on nerve structure and function Goal(s): To visualize nerve fascicles at high resolution and to determine the impact of fascicle size on quantitative MR parameters. Approach: Combination of high resolution T2-weighted imaging at 7T and quantitative (DTI, T2R) imaging at 3T in 10 polyneuropathy patients and 10 controls. Results: Nerve fascicles were larger in patients compared to controls. There was a negative correlation between fascicular diameter and number of fascicles. The fascicular diameter correlated negatively with fractional anisotropy and positively with T2. Impact: The results indicate that polyneuropathies are associated with a fusion of nerve fascicles which results in an increase in fascicular diameter and a reduced number of fascicles. This is related to a decline in quantitative parameters that codify nerve function.