[Sequential magnetic resonance imaging and neurophysiological studies in a patient with inferior spinal cord infarction].

A 66-year-old woman suddenly developed anterior spinal artery syndrome with complete flaccid paraplegia, superficial sensory disturbance caudally to the L5 dermatome level with preservation of deep sensation, incontinence, and absent deep tendon reflexes in both legs. An MRI of the whole spine and an analysis of the CSF 4 hours after onset were normal. The electrophysiological study showed an absence of F wave on the posterior tibial nerve stimulation on admission, while the peripheral nerve conduction velocities and amplitudes of upper and lower limbs were normal. T2-weighted MRI 4 days after onset demonstrated an area of high signal intensity in the gray and white matters of the epiconus and conus medullaris, and T1-weighted MRI showed the swelling. Three weeks later, F wave became evoked nd the high signal areas on axial T2-weighted MRI were localized in the bilateral anterior horns of the gray matter. T1-weighted MRIs after an administration of Gd-DTPA 3 and 7 weeks after onset demonstrated an enhancement of the ventral roots of the lumbar nerves and cauda equina, while the enhancements disappeared 8 months after onset. The patient was finally able to walk independently over 10 meter. An absent F wave was an only positive finding at the hyperacute (hours after onset) stage of the spinal cord infarction.