Temporal Lobe Epilepsy with Amygdala Enlargement: A Morphologic and Functional Study

From the Radioisotope Research Center, Kyoto University, Kyoto, Japan (ST)
Journal of neuroimaging: official journal of the American Society of Neuroimaging (Impact Factor: 1.73). 02/2012; 24(1). DOI: 10.1111/j.1552-6569.2011.00694.x
Source: PubMed


BACKGROUND AND PURPOSETemporal lobe epilepsy (TLE) with nontumoral amygdala enlargement (AE) has been reported to be a possible subtype of TLE without hippocampal sclerosis (HS). The purpose of this study was to clarify morphologic and functional characteristics of TLE with AE (TLE + AE). METHODS
We evaluated gray matter volume and cerebral glucose hypometabolism using magnetic resonance imaging (MRI) voxel-based morphometry (VBM) and voxel-based statistical analysis of [F-18]-fluorodeoxyglucose positron emission tomography (FDG-PET) images in 9 patients with TLE + AE as compared with controls. For VBM analysis, we recruited 30 age- and sex-matched healthy volunteers as controls. For the comparison of FDG-PET analysis, 9 patients with definite mesial TLE with HS (MTLE + HS), and 16 age- and sex-matched healthy controls were recruited. RESULTSIn patients with TLE + AE, a significant increase in gray matter volume was found only in the affected amygdala, and no significant decrease in gray matter volume was detected. In addition, significant glucose hypometabolism was observed in the affected amygdala, whereas significant glucose hypometabolism in the hippocampus, a prominent feature of definite MTLE+HS, was not observed. CONCLUSIONSTLE + AE is different from MTLE + HS from morphologic and functional points of view, and the enlarged amygdala per se is potentially an epileptic focus in patients with partial epilepsy.

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Available from: Shigetoshi Takaya
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    • "FDG-PET is widely used to define epileptogenic cortical areas, and also to guide the placement of intracranial electrodes, because of its high detection levels of seizure focus (Juhasz et al., 2000). On the other hand, MR imaging has been reported to have a lower detectability (King et al., 1998; Engel et al., 2008; Takaya et al., 2012). However, this study has successfully shown that the increased signal intensity areas on DIR-WM corresponded well to the hypometabolic areas on FDG- PET, especially in the anterior temporal lobe, and detection of seizure focus laterality was almost equivalent between DIR-WM and FDG-PET. "
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    ABSTRACT: To quantitatively compare the diagnostic capability of double inversion-recovery (DIR) with F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) for detection of seizure focus laterality in temporal lobe epilepsy (TLE). This study was approved by the institutional review board, and written informed consent was obtained. Fifteen patients with TLE and 38 healthy volunteers were enrolled. All magnetic resonance (MR) images were acquired using a 3T-MRI system. Voxel-based analysis (VBA) was conducted for FDG-PET images and white matter segments of DIR images (DIR-WM) focused on the whole temporal lobe (TL) and the anterior part of the temporal lobe (ATL). Distribution of hypometabolic areas on FDG-PET and increased signal intensity areas on DIR-WM were evaluated, and their laterality was compared with clinically determined seizure focus laterality. Correct diagnostic rates of laterality were evaluated, and agreement between DIR-WM and FDG-PET was assessed using κ statistics. Increased signal intensity areas on DIR-WM were located at the vicinity of the hypometabolic areas on FDG-PET, especially in the ATL. Correct diagnostic rates of seizure focus laterality for DIR-WM (0.80 and 0.67 for the TL and the ATL, respectively) were slightly higher than those for FDG-PET (0.67 and 0.60 for the TL and the ATL, respectively). Agreement of laterality between DIR-WM and FDG-PET was substantial for the TL and almost perfect for the ATL (κ = 0.67 and 0.86, respectively). High agreement in localization between DIR-WM and FDG-PET and nearly equivalent detectability of them show us an additional role of MRI in TLE.
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    • "Significant enlargement of amygdala volumes has been reported in patients with MTLE with psychiatric disorders such as depression and psychosis [9] [10]. In other studies about MTLE without HS (MRI-negative MTLE), enlarged amygdalae have been investigated as the possible lesion associated with seizure origin [11] [12] [13] [14]. "
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    ABSTRACT: Mesial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS) is considered an electroclinical syndrome, and there is a debate whether it is a unique disease or an entity with distinct subtypes. Together with other mesial temporal structures, the amygdala is important in the epileptogenic network of patients with MTLE with HS. During automatic volumetric analysis of mesial structures in a group of 102 patients with MTLE with MRI signs of HS, we observed significant amygdala enlargement in 14 (14%) individuals compared to a group of 79 healthy subjects. The increased amygdala volume was contralateral to the epileptogenic zone and MRI signs of HS in 93% of these patients. Patients with MTLE with HS and enlarged amygdala had significantly earlier epilepsy onset than those without an increase of amygdala volumes. Mesial temporal lobe epilepsy with HS and enlarged amygdala may be a part of the spectrum of this condition.
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    ABSTRACT: Paroxysmal kinesigenic dyskinesia (PKD) is a rare disease characterized by involuntary movements triggered by a sudden initiation of voluntary movement. No EEG abnormalities are observed both during and between PKD attacks. Clinically, the involuntary movements are readily controlled by sodium channel-related antiepileptic drugs such as carbamazepine [1] and phenytoin [2]. Two hypotheses have been proposed for the pathophysiology of PKD; kinesthetic reflex epilepsy [3] and basal ganglia functional abnormality [4], but no consensus has been reached.We report a patient with amygdala enlargement who manifested complex partial seizure (CPS) following PKD attack.
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