cqvip:Objective: To determine the extent and severity of mesial temporal and subcor tical signal abnormalities in patients with partial epilepsy. Methods: T2 relaxation time maps were acquired in 50 c onsecutive patients and 55 control subjects on a 3 T MRI scanner. Twenty-two p atients had hippocampal sclerosis (HS), 16 had malformations of cortical develop ment (MCD), and 12 had no obvious MR abnormalities (normal MR). The following ei ght regions were measured bilaterally: hippocampus, anterior temporal lobe (ATL) white matter, amygdala, frontal lobe white matter, caudate, putamen, pallidum, and thalamus. Results: In patients with HS, increased T2 relaxation times were f ound in the ipsilateral hippocampus and ATL but not in subcortical nuclei. In pa tients with MCD, increased T2 relaxation times were found in the temporal lobe ( hippocampus, ATL) and in subcortical areas (caudate, putamen, and pallidum); in patients with normal MR, increased T2 relaxation times were found in the hippoca mpus and putamen. The degree of abnormality did not correlate with the duration of epilepsy or the estimated seizure load. Conclusions: Mesial temporal structur es show increased T2 relaxation times not only in patients with hippocampal scle rosis but also in patients with a seizure focus remote from the hippocampus. Pat ients with normal MR and focal malformations of cortical development have increa sed T2 relaxation times in subcortical structures. Therefore, abnormalities in T 2 relaxation time can be found remote from the seizure focus. They cannot be sim ply attributed to secondary seizure effects.
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