Institution: | 1. Department of Orthopedic Surgery, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan;2. Healthcare Business Groupe, RICOH Company, Ltd., 2-3-10 Kandasurugadai, Chiyoda-ku, Tokyo 101-0062, Japan;3. Department of Advanced Technology in Medicine, Graduate School of Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8510, Japan;4. Faculty of Health Sciences, Aomori University of Health and Welfare, 58-1 Mase, Hamadate, Aomori-shi, Aomori 030-8505, Japan;5. Applied Electronics Laboratory, Kanazawa Institute of Technology, Kanazawa-shi, Ishikawa 920-1331, Japan |
Abstract: | ObjectiveTo visualize neural activity in the brachial plexus using magnetoneurography (MNG).MethodsUsing a 124- or 132-channel biomagnetometer system with a superconducting quantum interference device, neuromagnetic fields above the clavicle and neck region were recorded in response to electrical stimulation of the median and ulnar nerves in five asymptomatic volunteers (four men and one woman; age, 27–45 years old). Equivalent currents were computationally reconstructed from neuromagnetic fields and visualized as pseudocolor maps. Reconstructed currents at the depolarization site and compound nerve action potentials (CNAPs) at Erb’s point were compared.ResultsNeuromagnetic fields were recorded in all subjects. The reconstructed equivalent currents propagated into the vertebral foramina, and the main inflow levels differed between the median nerve (C5/C6–C7/T1 vertebral foramen) and the ulnar nerve (C7/T1–T1/T2). The inward current peaks at the depolarization site and CNAPs showed high linear correlation.ConclusionsMNG visualizes neural activity in the brachial plexus and can differentiate the conduction pathways after median and ulnar nerve stimulations. In addition, it can visualize not only the leading and trailing components of intra-axonal currents, but also inward currents at the depolarization site.SignificanceMNG is a novel and promising functional imaging modality for the brachial plexus. |