Magnetoneurography as a novel functional imaging technique for cervical myelopathy.

OBJECTIVE

To evaluate the efficacy of magnetoneurography (MNG) in examination of neurological conditions in degenerative cervical myelopathy.

METHODS

The left median and ulnar nerves were electrically stimulated in 25 healthy participants and 21 patients. The evoked magnetic fields were recorded using a 132-channel superconducting quantum interference device biomagnetometer system and spatiotemporal changes in reconstructed action currents were evaluated. The correspondence of the MNG and MRI diagnoses with neurological findings was evaluated by two board-certified orthopaedists.

RESULTS

Evoked magnetic fields were recorded in all participants. In 16 patients, there was no inconsistency between the MRI and MNG findings. In the remaining five cases, the lesions diagnosed by MNG were at a lower level than those diagnosed by MRI.

CONCLUSIONS

MNG was able to visualise the spatiotemporal course of neural currents, which is difficult to record in conventional electrophysiological examinations. Because the lesional level of the spinal cord in MRI is not always consistent with the neurological findings, MNG might be able to detect the electrophysiological change in the spinal cord at a level below the compression site.

SIGNIFICANCE: MNG has the potential to be a comprehensible imaging technique and to provide novel neurological findings.