Interictal regional cerebral blood flow and electrical source analysis in patients with complex partial seizures

Recently, new methods of EEG source analysis have been developed. Dipole modeling and brain distributed source analysis localize in three-dimensions the origin of the electrical source of spikes registered in EEG. With single photon emission computed tomography (SPECT), it is possible to detect hypo- and hyperperfusion zones. Our aim in this study is to compare the regions where the electrical sources are detected, with the hypoperfusion regions in patients with complex partial seizures (CPS).

The concordance of localization with dipole analysis, brain distributed source analysis and regional cerebral flow blood in patients with CPS was studied. The hypoperfusion zones detected with interictal SPECT were compared with electrical sources localized with brain electric source analysis (BESA) and brain distributed source analysis with variable resolution electromagnetic tomography (VARETA).

Hypoperfusion zones were found to localize with the origin of dipoles in 18 cases (90%), between lobes in 17 (85%) and between mesial or lateral regions in the temporal lobe in 12 cases (60%). With VARETA, agreement between side of hypoperfusion and electrical current source localization was found in 18/20 cases (90%), with lobes in 17 (85%) and with mesial or lateral regions of the temporal lobe only in 2 cases (10%).

Hypoperfusion zones in interictal SPECT of patients with CPS are in agreement with the origin of dipoles in 85% of the cases, but in specifics zones of temporal lobe the agreement falls to 60%. The concordance of hypoperfusion zones was better with dipole analysis than with VARETA.