[Interictal basal brain SPECT versus interictal activated brain SPECT in temporal cryptogenic epilepsy]
M A Gudin1, B Catalán Bernardos, V Poblete García
1Neurología, Hospital Ntra. Sra. de Alarcos, Ciudad Real, Spain. mariagudin@arrakis.es
Insights
Interictal epileptiform activity in temporal epilepsy patients is linked to reduced brain perfusion in the temporal lobe, thalamus, and cerebellum. This suggests interictal epileptiform activity may represent a post-ictal state.
Area of Science:
- Neurology
- Neuroscience
- Medical Imaging
Background:
- Interictal epileptiform activity (IEA) is common in temporal epilepsy but its nature remains unclear.
- IEA may represent microseizures or brain inhibition mechanisms.
- Understanding brain metabolism during IEA is crucial for temporal epilepsy management.
Purpose of the Study:
- To investigate brain perfusion during basal and interictal states in temporal epilepsy patients.
- To quantify temporal, thalamic, and cerebellar perfusion using SPECT HMPAO.
- To elucidate the metabolic underpinnings of IEA in temporal epilepsy.
Main Methods:
- SPECT HMPAO imaging was performed on 24 temporal epilepsy patients (9 male/15 female, mean age 36.5 years).
- Two studies were conducted: a basal state (no ictal activity) and an activated state (during IEA with ≥10 graphoelements/EEG page).
- Digital analysis quantified perfusion in temporal, thalamic, and cerebellar regions.
Main Results:
- A significant decrease in thalamic, temporal, and cerebellar perfusion was observed during the activated state compared to the basal state (p < 0.001).
- A strong statistical relationship (R2 > 0.9) was found between perfusion in these three regions in both states.
- These findings highlight a consistent pattern of reduced perfusion associated with IEA.
Conclusions:
- Temporal epilepsy is associated with significantly decreased thalamic, temporal, and cerebellar perfusion during interictal activity.
- The observed perfusion changes suggest that IEA might reflect a post-ictal state.
- Further research into IEA's metabolic correlates can inform epilepsy treatment strategies.
Introduction:
Interictal epileptiform activity (IEA) is a common finding in temporal epileptic patients. The nature of the IEA is not entirely understood; it may be microseizures or just a negative phenomenon expressing brain inhibition mechanisms. In order to understand how brain metabolism is during interictal activity we studied a group of patients with SPECT HMPAO during basal condition no ictal activity - and when the same patients were having interictal activity. Temporal, thalamic and cerebellar perfusion were quantified by a digital method.
Patients And Methods:
Two studies were performed in 24 epileptic patients: (9/15:M/F, 36,5 14,6 years). The MRI was normal or had minimal changes. Previous EEG had showed frontotemporal foci. The patients were studied by SPECT HMPAO performed with a STARCAM 3.200 equipment, the images being obtained by high resolution collimator with circular orbit 64 images, 30 s per image. The first study was performed when there was no anomaly in the EEG (basal study). In the second study (activated study) the radioligand was injected when the EEG showed at least 10 graphoelements (spike, polispikes, or sharp waves per EEG page).
Results:
Thalamic, temporal and cerebellar perfusion decreased significantly in the activated state compared to the basal one (p < 0.001). The statistical relationship between these three locations was studied. There was a significant relationship (p < 0.001) between thalamic, temporal, and cerebellar perfusion, both in basal state and in the activated one. The correlation index was R2 > 0.9.
Conclusions:
For the cases studied, temporal epilepsy is associated to a significant decrease in thalamic, temporal and cerebellar perfusion in the basal state compared to the activated one. This finding may indicate that IEA expresses a post-ictal state.
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