Nerve Diameter and DTI Parameters Maybe Potential Markers for Clinical Trial in Patients With Charcot-Marie-Tooth Disease Type 1A.

BACKGROUND

Charcot-Marie-Tooth disease type 1A (CMT1A) is the most common form of CMT, varying from asymptomatic to severe. The aim of this study was to investigate whether the diffusion tensor imaging (DTI) parameters and diameter of the proximal nerves, as measured by magnetic resonance neurography, can be used as a potential marker to reflect the progression.

METHODS

This was a prospective study including 45 consecutive patients with CMT1A, divided into three subgroups by foot dorsiflexion muscle strength: mild cases (Group 1), moderate cases (Group 2), and severe cases (Group 3). We compared the diameter, fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) of the L4-L5 nerve roots, femoral nerve (FN), and sciatic nerve (SN) of patients with CMT1A with those of healthy controls (HCs), and among subgroups. We followed 19 patients for 15 months and analyzed the change.

RESULTS

The diameters of the L4 nerve roots and SN were significantly larger in Group 3 than in Group 1 and HCs. FA was decreased and MD and AD were increased significantly in Group 3 compared to Group 1, with the differences being more pronounced in SN and L4 nerve roots. After the follow-up period, the diameters, FA, MD, AD, and RD of the nerve roots were changed significantly.

CONCLUSIONS

Nerve diameter, FA, MD, and AD on DTI could be sensitive measures reflecting disease severity and progression in patients with CMT1A, prominently in proximal nerve roots. SN and L4 nerve roots may be suitable indices.