Provoked ictal SPECT in temporal and extratemporal drug-resistant epileptic patients: comparison of Statistical Parametric Mapping and qualitative analysis.

OBJECTIVE: To compare Statistical Parametric Mapping (SPM) with qualitative analysis of provoked ictal SPECT, in terms of both diagnostic yield and efficacy in identifying the epileptogenic zone of temporal and extratemporal epileptic patients. METHODS: We included in the study 27 drug-resistant epileptic patients submitted to provoked ictal SPECT and for whom both SPM and qualitative analysis were obtained. A comparison between visual SPECT analysis and SPM results was performed in terms of lateralization and localization of the ictal hyperperfusion areas. Then, hyperperfusion areas were compared to epileptogenic zones to assess whether they co-localized or not. RESULTS: In twenty patients, a co-localization was found between hyperperfusion areas detected by both qualitative and SPM analysis of provoked ictal SPECT and epileptogenic zones. A concordance between SPM and qualitative analysis in all but two patients was obtained. These findings were observed for both temporal and extratemporal epilepsies. CONCLUSIONS: The co-localization between provoked ictal SPECT hyperperfusion areas and epileptogenic zones found in most patients supports the usefulness of this technique in integrating data provided by neuroimaging and electroclinical correlations to correctly define epileptogenic zone. Moreover, this preliminary work suggests that SPM as entirely objective methodology is feasible and can be accurate also after provoked ictal SPECT.