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Objective: To assess factors associated with favorable outcome in refractory insular epilepsy treated by volume-based stereotactic radiofrequency thermocoagulation (RFTC)., Methods: We performed volume-based RFTC in 19 patients (11 males, 7-44 years old). The volume for thermocoagulation was identified by multimodal data including electroencephalography (EEG)-video, magnetic resonance imaging (MRI), and fluorodeoxyglucose-positron emission tomography (PET) in all patients, and epileptogenic zone (EZ) was assessed by stereo-electroencephalography (SEEG) in 16. MRI showed insular lesions in four patients (benign tumors, n = 2; focal cortical dysplasia [FCD], n = 1; polymicrogyria, n = 1). MRI was negative in 15 cases; however, PET was positive in 18, and FCD pattern was detected by SEEG in nine cases. The dominant hemisphere was involved in 12 cases. RFTC was performed as a separate procedure after SEEG, or as a single MRI-guided procedure. The insular volume to be coagulated was determined by a tridimensional identification of the epileptogenic cortex using MRI, PET, and SEEG, and was destroyed with coalescent thermal lesions., Results: Seizure-free outcome was achieved in 10 patients (53%), including Engel class IA in three (follow-up = 1-12 years, mean = 5.4). The responder rate (including Engel classes I-III) was 89%. Transient postoperative deficits (mild hemiparesia, dysarthria, hypoesthesia, dysgeusia) were observed in eight patients (42%), with rapid and total recovery in all but one with persistent mild dysarthria. Neurological deficits were related to higher number of RFTC procedures (P = .036) and greater volume of RFTC (P = .028). Neuropsychological status was unchanged or improved in all; however, psychiatric status transitorily worsened in three patients. Factors contributing to seizure-free outcome were the detection of FCD pattern (P = .009), localized EZ (P = .038), low RFTC volume (P = .002), low number of RFTC procedures (P = .001), and low RFTC volume/number ratio (P = .012). Optimal volume of RFTC around 2 cm 3 offered the best compromise between efficacy and safety., Significance: RFTC may be curative in insular epilepsy after accurate localization of EZ with SEEG. Best outcome was associated with low volume of thermolesions., (Wiley Periodicals, Inc. © 2019 International League Against Epilepsy.) more...

Purpose: Type 2 focal cortical dysplasia (FCD2) is one of the main causes of refractory partial epilepsy, but often remains overlooked by MRI. This study aimed to elucidate whether 3T MRI offers better detection and characterization of FCD2 than 1.5T, using similar coils and acquisition time., Methods: Two independent readers reviewed the 1.5T and 3T MR images of 25 patients with histologically proven FCD2. For both magnetic fields, the ability to detect a lesion was analyzed. We compared the identification of each of the five criteria typical of FCD2 (cortical thickening, blurring, cortical signal changes, subcortical signal changes, and "transmantle" sign) and artifacts, using a four-point scale (0-3). Interobserver reliability for lesion detection was calculated., Key Findings: Seventeen lesions (68%) were detected at 3T, two of which were overlooked at 1.5T. Interobserver reliability was better at 3T (κ = 1) than at 1.5T (κ = 0.83). The transmantle sign was more clearly identified at 3T than 1.5T (mean visualization score: 1.72 vs. 0.56; p = 0.002)., Significance: The use of 3T MRI in patients suspected of type 2 FCD improves the detection rate and the lesion characterization owing to the transmantle sign being more clearly seen at 3T. This point is of interest, since this feature is considered as an MR signature of FCD2., (Wiley Periodicals, Inc. © 2013 International League Against Epilepsy.) more...

Purpose: Type II focal cortical dysplasia (TTFCD), a highly epileptogenic lesion with severe epilepsy curable by surgery, is missed by magnetic resonance imaging (MRI) in about one third of cases. Little is known about the electroclinical presentation in these MRI-negative patients and a poor surgical outcome is frequently reported. We compared the clinical and neurophysiologic features in MRI-negative and MRI-positive cases in order to better identify candidates for surgery., Methods: Among 62 consecutive TTFCD patients (38 male, 24 female; 7-52 years old; 22 children) operated for intractable epilepsy, 25 (40%) presented negative MRI findings. We compared the history of epilepsy; the type, frequency, and distribution of seizures; neurologic examination cognitive and psychiatric impairment; interictal-ictal electroencephalography (EEG) and stereo-EEG (SEEG) data, fluorodeoxyglucose positron emission tomography (FDG-PET) data, neuropathologic findings; and surgical outcome in the MRI-negative and the MRI-positive groups., Key Findings: Severe partial epilepsy beginning in childhood, high seizure frequency including status epilepticus, stereotyped seizures suggestive of precise brain localization, extratemporal location and functional area involvement were characteristic and similarly found in both groups. On EEG, pseudorhythmic activity was found in about 40% of patients in each group. SEEG recordings demonstrated the typical pattern characterizing TTFCD in both groups. FDG-PET had a localization value in 84% of the MRI-negative cases and helped to delineate the dysplastic cortex in 65% of the MRI-positive cases. The combination of imaging and neurophysiologic data allowed us to perform safe and restricted resections, limited to a single gyrus in more than half of all cases. In addition, we were able to avoid invasive monitoring in most MRI-positive cases and even in some selected MRI-negative cases. The proportion of patients with a favorable surgical outcome was comparable in both groups (88% in MRI-negative and 94% in MRI-positive cases). The main difference between the groups was a significantly higher frequency of sleep-related epilepsy in the MRI-negative group (p = 0.028). This phenotypic characteristic provides a new argument for TTFCD in MRI-negative extratemporal epilepsy., Significance: These results lead us to consider that children or adult patients in whom electroclinical data suggest TTFCD, are highly suitable for surgery, especially for cryptogenic sleep-related epilepsy., (Wiley Periodicals, Inc. © 2012 International League Against Epilepsy.) more...