Abstracts

Rationale: We aimed to describe the interictal perfusion patterns seen in focal epilepsies by Arterial Spin Labelled sequences, as well as to evaluate its possible localization value. Methods: This is a cross-sectional study of 50 consecutive focal epilepsies diagnosed by semiology, structural MRI and EEG, who underwent a 3 TESLA MRI epilepsy protocol that included ASL sequences. Images were reviewed by two neuroradiologists. Perfusion abnormalities were classified as focal, or hemispheric when compared side by side. Results: The sample had 50% female, medium age 42.9 ( 17.2) years-old. Fifty-eight percent were symptomatic epilepsies and 73% refractory to treatment. The most frequent etiology was Malformation of Cortical Development (18%), followed by strokes (165) and tumors (12%). Lobe classification showed 48% of temporal, 30% frontal and 22% of posterior neocortical epilepsies. Complex partial seizures were the most frequent type (48%). Visual analyses of ASL sequences showed 80% evidences of perfusion interhemispheric asymmetries. Such abnormalities were more likely to be observed in patients with left hemispheric epileptogenic focus (p<0.05). There was a statistical tendency to observed hyperperfusion over the epileptogenic hemisphere. Up to 25% of patients had focal perfusion tighly correlated to the epileptogenic area as seen by EEG, enhanced focal perfusion was more likely to be observed. Conclusions: Interictal perfusion abnormalities analyzed by ASL sequences are very often observed in patients with focal epilepsies. Hyperperfusion is more likely to be observed over the epileptogenic area, and the ipsilateral hemisphere as well.