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Is amygdalohippocampectomy really selective in medial temporal lobe epilepsy? A study using positron emission
S Dupont1, A C Croizé, F Semah
1Service Hospitalier Frédéric Joliot, CEA, 4 place du Général Leclerc, 91406 Orsay, France. dupont@shfj.cea.fr
Purpose:
Selective amygdalohippocampectomy (SAH) is a surgical technique effective for the treatment of medial temporal lobe epilepsy, which selectively removes the epileptogenic hippocampus and amygdala but spares the temporal neocortex. However, the benefit of SAH in terms of functional outcome is debated. In this study, we aimed to assess the metabolic consequences of SAH.
Methods:
Volumetric magnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography (PET) studies were performed in nine patients with medial temporal lobe epilepsy associated with hippocampal sclerosis before and after SAH. Regions of interest were delineated on MRIs and then replaced on PET images using an automatic 3D image registration. We calculated absolute metabolic rates of glucose and normalized metabolic values in each region of interest.
Results:
The comparison between preoperative and postoperative metabolic values showed a statistically significant worsening of the hypometabolism on the ipsilateral temporal pole on the superior and the hippocampal levels (p < 0.05 and 0.0045, respectively). A postoperative increase of the metabolic activity also was noted in the contralateral anterior hippocampus (p < 0.05) and the orbitofrontal cortex bilaterally (p < 0.002 and 0.001, respectively)
Conclusions:
SAH functional benefit is controversial. SAH worsened significantly the hypometabolism of a temporal structure that was not surgically removed (i.e., the temporal pole), and it improved postoperatively the metabolic activity in the contralateral hippocampus and the orbitofrontal cortex. Whether this postoperative improvement is linked to the selectivity of the surgical procedure must be further clarified.
Insights
Selective amygdalohippocampectomy (SAH) worsened temporal pole metabolism but improved contralateral hippocampus and orbitofrontal cortex activity in epilepsy patients. Further research is needed to clarify SAH
Area of Science:
- Neuroscience
- Neurosurgery
- Epilepsy Research
Background:
- Medial temporal lobe epilepsy (MTLE) is often treated with selective amygdalohippocampectomy (SAH).
- The functional outcomes and metabolic consequences of SAH remain debated.
- Assessing metabolic changes post-SAH is crucial for understanding its efficacy.
Purpose of the Study:
- To evaluate the metabolic consequences of selective amygdalohippocampectomy (SAH) in patients with medial temporal lobe epilepsy (MTLE).
- To investigate changes in glucose metabolism following SAH using fluorodeoxyglucose positron emission tomography (PET).
Main Methods:
- Nine patients with MTLE and hippocampal sclerosis underwent volumetric MRI and FDG-PET scans before and after SAH.
- Regions of interest were identified on MRI and mapped to PET images using 3D image registration.
- Absolute and normalized metabolic rates of glucose were calculated for specific brain regions.
Main Results:
- SAH led to a significant worsening of hypometabolism in the ipsilateral temporal pole and superior/hippocampal levels.
- Postoperative metabolic activity increased in the contralateral anterior hippocampus.
- Bilateral orbitofrontal cortex showed a significant increase in metabolic activity post-SAH.
Conclusions:
- SAH resulted in paradoxical worsening of hypometabolism in the non-surgically treated temporal pole.
- Metabolic activity improved in the contralateral hippocampus and orbitofrontal cortex after SAH.
- The link between SAH's selectivity and observed metabolic improvements requires further investigation.