Lateralisation of epiletogenic focus in partial epilepsy: Correlations between perfusion DSC MRI and EEG data [Lateralizzazione del focolaio epilettogeno nell'epilessia parziale: Correlazioni tra RM perfusionale e dati EEG]

ABSTRACT: Seventeen subjects affected by cryptogenic partial epilepsy underwent long-term computer assisted video-EEG monitoring and DSC-MRI in the same session. Ten patients were affected by Temporal Lobe Epilepsy (TLE) and 7 by epilepsy of extratemporal origin (ExTE). MRI data were compared with EEG findings and accuracy of perfusion MRI was analyzed considering spiking rate and type of epilepsy. Perfusion MRI showed a relevant relative regional hyperperfusion pattern in the temporal, frontal and occipital regions in 8 out of 17 patients (47%). Patients were classified in two groups:patients with high spiking rate (HSR n=9) and with low spiking rate (LSR, n=8). The hyperperfusion region corresponded to the epileptogenic focus or to the hemisphere involved in the genesis of epileptic discharges in 7 (77.7%) out of 9 HSR patients. No patients with LSR showed significant asymmetries. In 5 out of 6 TLE-HSR patients (83.3%), DSC-MRI showed a relative hyperperfusion region concordant with EEG focus or hemisphere involved in the genesis of epileptic discharges; in patients with ExTE-HSR, the concordance was 66%. We concluded that DSC-MRI is a noninvasive procedure that may provide useful additional information to lateralize and/or localize the epileptogenic zone when interictal epileptiform activity is sufficiently elevated; in addition, the correlation between perfusion patterns and interictal EEG is more evident in patients with TLE than in those with ExTE.