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Objective In the presurgical workup of MRI-negative (MRI−, or “nonlesional”) pharmacoresistant focal epilepsy (PFE) patients, discovering a previously undetected lesion can drastically change the evaluation and likely improve surgical outcome. Our study utilizes a voxel-based MRI post-processing technique, implemented in a morphometric analysis program (MAP), to facilitate detection of subtle abnormalities in a consecutive cohort of MRI− surgical candidates.

Objective MRI-negative (MRI–) pharmacoresistant focal epilepsy (PFE) patients are most challenging for epilepsy surgical management. This study utilizes a voxel-based MRI postprocessing technique, implemented using a morphometric analysis program (MAP), aiming to facilitate detection of subtle focal cortical dysplasia (FCD) in MRI– patients. Furthermore, the study examines the concordance between MAP-identified regions and localization from magnetic source imaging (MSI). Methods Included in this retrospective study were 25 MRI– surgical patients. MAP was performed on T1-weighted MRI, with comparison to a normal database. The pertinence of MAP+ areas was confirmed by MSI, surgical outcome and pathology. Analyses of MAP and MSI were performed blindly from patients' clinical information and independently from each other. Results The detection rate of subtle changes by MAP was 48% (12/25). Once MAP+ areas were resected, patients were more likely to be seizure-free (p = 0.02). There were no false positives in the 25 age-matched normal controls. Seven patients had a concordant MSI correlate. Patients in whom a concordant area was identified by both MAP and MSI had a significantly higher chance of achieving a seizure-free outcome following complete resection of this area (p = 0.008). In the 9 resected MAP+ areas, pathology revealed FCD type IA in 7 and type IIB in 2. Interpretation MAP shows promise in identifying subtle FCD abnormalities and increasing the diagnostic yield of conventional MRI visual analysis in presurgical evaluation of PFE. Concordant MRI postprocessing and MSI analyses may lead to the noninvasive identification of a structurally and electrically abnormal subtle lesion that can be surgically targeted. Ann Neurol 2014;759–770

Objective To explore the prognostic implications of epilepsy duration and age at surgery for seizure outcomes after frontal lobe epilepsy (FLE) surgery. Methods We reviewed 158 patients who underwent FLE surgery from 1995 to 2010. The primary outcome was seizure freedom at last follow-up (Engel class IA). Analyses employed Cox proportional and multiphase hazard modeling. Results The mean age at surgery was 20.4 years, and mean epilepsy duration was 12.0 years. The estimated chance of seizure freedom was 66% (95% confidence interval [CI] = 62–68) at 1 postoperative year, 52% (95% CI = 48–56) at 2 years, and 44% (95% CI = 39–49) at 5 years and beyond. Seventy-five percent of recurrences occurred within 6 postoperative months. Both younger age at surgery (

To explore the prognostic implications of epilepsy duration and age at surgery for seizure outcomes after frontal lobe epilepsy (FLE) surgery.We reviewed 158 patients who underwent FLE surgery from 1995 to 2010. The primary outcome was seizure freedom at last follow-up (Engel class IA). Analyses employed Cox proportional and multiphase hazard modeling.The mean age at surgery was 20.4 years, and mean epilepsy duration was 12.0 years. The estimated chance of seizure freedom was 66% (95% confidence interval [CI] = 62-68) at 1 postoperative year, 52% (95% CI = 48-56) at 2 years, and 44% (95% CI = 39-49) at 5 years and beyond. Seventy-five percent of recurrences occurred within 6 postoperative months. Both younger age at surgery (18 years) and shorter epilepsy duration (5 years) correlated with better seizure outcomes on univariate analysis, but only epilepsy duration remained statistically significant after multivariate modeling. Independent poor prognostic indicators included left-sided resections and acute postoperative seizures (APOSs; whole model log-rank test p0.0001). APOSs were particularly predictive of early epilepsy recurrence, starting within 6 postoperative months (adjusted risk ratio [RR] = 4.42, p0.0001), whereas long epilepsy duration correlated with late recurrences (RR = 6.25, p0.0001). Worse outcomes were seen with longer epilepsy duration for duration cutoffs of 2, 5, and 10 years independently for adults and children, although statistical significance was only achieved in children (66% seizure free at 5 postoperative years if operated on within 5 years of epilepsy onset vs 31% if later; p = 0.01).Early resection may improve seizure outcomes of FLE surgery, particularly in children.