MRI, 1H-MRS, and functional MRI during and after prolonged nonconvulsive seizure activity

Abstract

Article abstract-Background: Various structural and functional changes, such as focal edema, blood flow, and metabolism, occur in the cerebral cortex after focal status epilepticus. These changes can be assessed noninvasively by means of MRI techniques, such as fluid-attenuated inversion recovery (FLAIR), EEG-triggered functional MRI (EEG-fMRI), and proton MR spectroscopy (MRS). Methods: The authors report on a 40-year-old patient with nonlesional partial epilepsy in the left posterior quadrant in whom these MRI techniques were applied in an active seizure focus and repeated during a follow-up of 1 year. Results: FLAIR imaging taken at the time of status epilepticus showed a signal hyperintensity in the occipital region.

Metabolic alteration transients during paroxysmal activity in an epileptic patient with fixation-off sensitivity: a case study

“…Concerning the static Cho elevation during FOS activity in epileptic focus compared with the contralateral side, which confirms the results of Lazeyras et al [27] and Lundbom et al [28] (obtained at rest), the result suggests that neuronal tissue subject to prolonged paroxysmal activity may result in membrane damage or gliosis.…”

“…Lazeyras et al [27] reported an increase of Cho and Lac and a decrease of NAA in the occipital region of a subject suffering from nonlesional epilepsy in the posterior quadrant immediately following nonconvulsive seizure activity; Cho and Lac levels progressively normalized within 30 days. A similar Cho increase with respect to the region contralateral to seizure was identified with MRS imaging by Lundbom et al [28], who reported also focal increase of Cr and decrease of NAA.…”

Reduction in Glutamine/Glutamate Levels in the Cerebral Cortex after Adrenocorticotropic Hormone Therapy in Patients with West Syndrome

“…In our WS patients, Cho signals tended to decrease over time but did not differ from those of controls, suggesting the gradual reduction during normal development. Although the Cho signal can be temporarily increased by prolonged epileptic phenomena (Lazeyras et al 2000), signal intensities are not different from controls after the elimination of seizures.…”

MRI Abnormalities Induced by Seizures

“…A pial or cortico-pial contrast enhancement can also be disclosed, particularly in larger TPMAs with a subcortical component. In the cases in which a protonic magnetic resonance spectroscopy (MRS) was obtained periictally, the most consistent findings were an increase in the lactate levels and choline and a decrease in N-acetyl-aspartate (Castillo et al, 2001;Lazeyras et al, 2000;Mueller et al, 2001), with the levels of myoinositol possibly fluctuating during and after seizures (Wellard et al, 2003). Generally, these signal abnormalities are colocalized in the same brain regions.…”