Imaging findings of Lower Extremity Peripheral Nerves in Charcot-Marie Tooth

Objective: Charcot-Marie Tooth (CMT) disease is the most common inherited neurological disorder of lower motor neurons, and manifests with lower extremity weakness and sensory defects. Musculoskeletal imaging findings in CMT include cavovarus foot alignment and peripheral muscle atrophy. There is a lack of literature describing the imaging appearance of peripheral nerves in patients with CMT. The objective of this study is to characterize the magnetic resonance (MR) and computed tomography (CT) imaging features of lower extremity peripheral nerves in patients with CMT compared to a control group. Materials and Methods: MR and CT images of the ankle/foot and/or knee were evaluated in a group of 9 patients with CMT and 10 age and sex matched control patients. Mean diameter of the common peroneal nerve and tibial nerve were recorded. T1 and fluid sensitive sequence signal of the intrinsic knee and/or foot musculature was also recorded. Results and conclusions: Mean nerve diameter of the tibial nerve was significantly larger in the CMT group at 6.43 mm compared to 3.55 mm in controls. Mean diameter of the common peroneal nerve was significantly larger in the CMT group at 6.23 mm compared to 3.5 mm in controls. Nerve signal on T1, T2, and post contrast imaging was the same between the two groups. 88.9% of CMT patients had patchy T2 muscle signal and 82% had intrinsic foot atrophy compared to none of the controls.