Pilot study investigating the effect of the static magnetic field from a 9.4-T MRI on the vestibular system

To objectively evaluate workers' sensory symptoms and vestibular function after exposure to a strong, new generation 9.4-T Magnetic Resonance Imaging (MRI) scanner.

Six MRI employees underwent standardized electronystagmographic evaluation, postural testing, and caloric function at baseline evaluation, 30 minutes postexposure to 9.4 T static field and at a 3-month follow-up.

All participants noted sensory symptoms after exposure. No overall deterioration in vestibular function was noted following 30-minute exposure or at a 3-month follow-up. A higher occurrence of tonic vestibular asymmetry, hyperreactive caloric responses, and spontaneous nystagmus was noted compared with that of the normal population.

Workers exposed to the new, stronger MRIs experience sensory symptoms but it is unclear as yet whether long-term vestibular damage occurs. The higher rates of vestibular changes noted could argue for improved worker surveillance and exposure control.