Abstracts

RATIONALE: To detect regional alterations of brain perfusion and diffusion during epileptic seizures and during the immediate postictal state METHODS: We examined 6 patients: one during a focal status epilepticus in his right second digit, 2 patients during a habitual aura, 3 patients during the immediate postictal phase from 8 minutes to 3h postictally. We used serial fast acquisition, high resolution MRI (Siemens Sonata with 40mT gradient strength: 1.5T, DWI: TE=83ms, TR=5000ms, b=1000 s/mm2, PWI: TE= 45ms, TR= 1500ms, 60 acquisitions) for detection of dynamic alterations of regional brain perfusion and diffusion in the epileptogenic zone and other defined regions of interest. All intraictal and postictal examinations were compared to base-line conditions of the same patients. RESULTS: (1) during the focal status, which had lasted for >4 days the apparent diffusion coefficient was increased by 15-20% in a circumscribed zone of the precentral gyrus considered to be epileptogenic, (2) 8-60 minutes after a complex partial seizure the ADC decreased by 15-25% in the epileptogenic zone and returned to base-line during the following 2h, (3) during the epigastric aura (n=2) perfusion in the epileptogenic hippocampus changed from interictal hyperperfusion to postictal hypoperfusion within 2 minutes, at the same time perfusion in the adjacent parahippocampal gyrus changed from hypo- to hyperperfusion, (4) following a complex partial seizure brain perfusion decreased by 51% (8 minutes) and 34% (15 minutes) postictally in the ictogenic hippocampus when compared to the contralateral side. CONCLUSIONS: Serial imaging of spatiotemporal alterations of brain diffusion and perfusion by high resolution (latest generation) fast acquisition MRI appears to be a powerful tool for delineation of the epileptogenic zone.