Multichannel SQUID Magnetoneurograph System for Functional Imaging of Spinal Cords and Peripheral Nerves

We developed a superconducting quantum interference device (SQUID)-based biomagnetometer system for magnetoneurograms. The system was improved from a previously reported prototype magnetospinograph (MSG)/neurograph (MNG) system to satisfy the additional requirements that arose when we investigated practical clinical applications of the MSG/MNG in a hospital. The dimensions of the vector-type SQUID flux sensor array were increased to 150 mm × 188 mm, and the shape of the cryostat was modified so that the peripheral nerves at different body parts of a subject who assumed various postures, including positions provoking neurological symptoms, could be examined. In this paper, the improved MNG system is described in detail. Functional imaging of the brachial plexuses of subjects whose arms were in the abduction and external rotation position, which is one of the typical symptom-provocative positions for the shoulder, was achieved using the improved MNG system.