Cortical Deformation Zone in Neocortical Epilepsy: 3D Surface-Projection Rendering of Brain MRI / 대한간질학회지

PURPOSE: The detection of epileptogenic lesion plays an important role in the management of patients with partial epilepsy. Although the development of MRI improved the examination of cerebral hemispheres greatly, many patients with neocortical temporal lobe epilepsy (TLE) or extratemporal lobe epilepsy (extra-TLE) still show no lesion in conventional two-dimensional (2D) images. To increase the yield of MRI in those patients, we performed three-dimensional (3D) surface-projection rendering (SPR) of the cerebral hemispheres. METHODS: Conventional 2D MRI (T1, T2, FLAIR, thin slice SPGR) and 3D SPR were performed in 24 patients with neocortical TLE and extra-TLE, and 20 normal subjects. Sulcogyral patterns were evaluated blindly to clinical information. The locations of the epileptogenic zone, ictal onset zone (IOZ) and irritative zone (IRZ) were determined by intracranial EEG monitoring and epilepsy surgery. RESULTS: The 2D MRI identified epileptogenic lesions in five of the 10 neocortical TLE (50%) and five of the 14 extra-TLE (35.7%). 3D SPR revealed abnormal sulcogyral patterns in 9 of the 10 neocortical TLE (90%) and 9 of the 14 extra-TLE (64.3%). Cortical deformation zones with sulcogyral anomalies included the whole area of IOZ in 10 (55.5%) and IRZ in 6 (33.3%), overlapped with IOZ in 7 (38.9%) and IRZ in 11 (61.1%), were connected to IOZ in 1 (5.6%) and IRZ in 1 (5.6%). CONCLUSION: 3D SPR of volumetric MRI data can detect epileptogenic structural lesions of neocortical epilepsy that are not visible in the conventional 2D images.

Ictal Cerebral Perfusion Patterns in Partial Epilepsy: SPECT Subtraction / 대한핵의학회잡지

PURPOSE: To investigate the various ictal perfusion patterns and find the relationships between clinical factors and different perfusion patterns. MATERIALS AND METHODS: lnterictal and ictal SPECT and SPECT subtraction were performed in 61 patients with partial epilepsy. Bath positive images showing ictal hypoperfusion and negative images revealing ictal hypoperfusion were obtained by SPECT subtraction. The ictal perfusion patterns of subtracted SPECT were classified into focal hypoperfusion, hypoperfusion-plus, combined hypoperfusion-hypoperfusion, and focal hypoperfusion only. RESULTS: The concordance rates with epileptic focus were 91.8% in combined analysis of ictal hypoperfusion and hypoperfusion images of subtracted SPECT, 85.2% in hypoperfusion images only of subtracted SPECT, and 68.9% in conventional ictal SPECT analysis. Ictal hypoperfusion occurred less frequently in temporal lobe epilepsy (TLE) than extratemporal lobe epilepsy. Mesial temporal hypoperfusion alone was seen only in mesial TLE while lateral temporal hypoperfusion alone was observed only in neocortical TLE. Hippocampal sclerosis had much lower incidence of ictal hypoperfusion than any other pathology. Some patients showed ictal hypoperfusion at epileptic focus with ictal hypoperfusion in the neighboring brain regions where ictal discharges propagated. CONCLUSION: Hypoperfusion as well as hypoperfusion in ictal SPECT should be considered for localizing epileptic focus. Although the mechanisrn of ictal hypopertusion could be an intra-ictal early exhaustion of seizure focus or a steal phenomenon by the propagation of ictal discharges to adjacent brain areas, further study is needed to elucidate it.