Abstracts

Rationale: We sought to evaluate the accuracy of the 3T-MRI to detect brain lesions in focal epilepsies.Methods: MRI of focal epilepsies were consecutively reviewed from a data base of 177 epileptic patients between January-2010 and May-2011. 3T-MRI included: 3D-MPRGE T1-IR and FLAIR; T2, SWI, ASL and DTI sequences. The reliability to localize the epileptic focus of the MRI, was obtained by comparing the concordance between the diagnostic before and after the MRI.Results: We recruited 144 focal epilepsies: Age: 42 ( 17) [16-84] years-old. Women 51%. Drug-resistant 56%. Most frequent epilepsies were Temporal or frontal (84%). MRI was normal in 42% of patients, however 12% showed unclassifiable lesions related to the epileptic focus. Causes of symptomatic epilepsies (46%) were: malformation of cortical development (10%), vascular (10%), tumours (8%), hippocampus sclerosis (7%), posttraumatic (6%) and others (10%). Advanced age was identified as a risk factor to have vascular epilepsy. The ROC curve established a best cut-off point to have no other than vascular cause in older than 71 years-old (Specifity:98%). There was relatively good concordance between the epileptogenic source localization pre- and post-MRI (K:0.6). Somehow, the lobe localization was modified in 19% patients (k:0.7) and lateralization in 26% (k:0.59) Conclusions: A 3T-MRI epilepsy protocols can achieve lesions related to the epileptic focus in 50% of patients. Patients over 71 years-old with focal epilepsy are more likely to have vascular lesions in the MRI. A good correlation between the electroclinical and neuroimaging localization exists, however the MR modifies a relevant number of diagnostics.