We report magnetic resonance neurography (MRN) findings in 3 patients with long-segment peripheral neuropathies following COVID-19 infection.

Post-infectious neurologic sequelae of COVID-19 are being increasingly reported. To date, no imaging findings of COVID-19-associated peripheral neuropathy have been published.

IRB-approved, retrospective review of clinical, electrodiagnostic (EDX), and MRN findings in 3 patients with COVID-19-associated long-segment peripheral neuropathies.

Patient 1: 50-year-old male awoke after a 3-week intubation (no prone positioning) for COVID-19 with inability to plantarflex/dorsiflex his left foot/toes and severe neuropathic pain. EDX 6 weeks later confirmed a severe sciatic neuropathy. Thigh MRN 3 months post onset revealed diffuse, T₂-weighted (T2W) signal hyperintensity of the sciatic nerve and hamstring muscle denervation.

Patient 2: 55-year-old male awoke after a 7-week intubation (no prone positioning) for COVID-19 with severe, left, upper-extremity weakness, numbness and pain. EDX suggested a patchy brachial plexopathy. MRN 3 months post onset revealed patchy, T2W signal hyperintensity of nerves from plexus to elbow and extensive denervation of arm muscles. Preliminary results from a medial brachial cutaneous nerve biopsy demonstrated marked axonal loss.

Patient 3: 24-year-old female developed paresthesias in the right ulnar nerve distribution 3 months after mild COVID-19, with profound hand weakness the following day. Initial EDX identified an ulnar nerve conduction block at the elbow. One month later, EDX showed reduced ulnar motor amplitudes and prolonged ulnar motor distal latency at the wrist. MRN 7 weeks post onset demonstrated ulnar nerve T2W signal hyperintensity from elbow to wrist, with denervation of all ulnar-innervated hand muscles.

MRN in all COVID-19 patients demonstrated long-segment, T₂-weighted signal hyperintensity of affected nerves, a scenario most commonly seen in inflammatory neuropathies. Those interpreting MRN should consider COVID-19 as an etiology when presented with a case of long-segment, peripheral neuropathy in a patient with active or recent infection.