Epilepsy research

Evaluation of amygdala pathology using (11)C-methionine positron emission tomography/computed tomography in patients with temporal lobe epilepsy and amygdala enlargement.

PMID 25847346


The association between amygdala enlargement (AE) and temporal lobe epilepsy (TLE) has increasingly been reported. However, the pathology of AE remains poorly understood. The purpose of this study was to explore AE pathology using (11)C-methionine (Met) positron emission tomography (PET)/computed tomography (CT) in patients who have TLE with AE. Twenty-six TLE patients with AE and 18 TLE patients without AE underwent (11)C-Met PET/CT and magnetic resonance imaging (MRI). (11)C-Met uptake in amygdala was evaluated by both visual inspection and semi-quantitative measurement. MRI was assessed visually and semi-quantitatively for AE. Laterality index (LI) was obtained by comparing the amygdala volumes of ipsilateral and contralateral sides. The clinical course and histopathological findings of all patients were also analyzed. On (11)C-Met PET/CT images, visual examination detected increased uptake in the enlarged amygdala in 7 of 26 (27%) TLE patients with AE, and the results were confirmed by semi-quantitative analysis. Among six TLE patients with AE who underwent surgery, histopathology revealed neoplasms (low grade astrocytoma and gangliocytoma) in two patients and focal cortical dysplasia in one patient with increased (11)C-Met uptake, but non-neoplastic lesions (focal cortical dysplasia, vacuolar degeneration, and hamartoma) in all three patients with no increased (11)C-Met uptake. On MRI, volume of the affected amygdala was significantly larger compared to the contralateral amygdala. LI was significantly higher in the group with AE than in the group without AE. This study revealed that some TLE patients with AE showed increased (11)C-Met uptake in the enlarged amygdala. (11)C-Met PET/CT is potentially useful for the evaluation of AE pathology, and may provide beneficial information for appropriate decision-making.