SPECT perfusion changes during complex partial seizures in patients with hippocampal sclerosis

Area of Science:

• Neuroscience
• Medical Imaging
• Epileptology

Background:

• Cerebral perfusion changes correlate with neuronal activity.
• Understanding the pathophysiology of complex partial seizures (CPS) in hippocampal sclerosis (HS) is crucial for epilepsy management.
• Temporal lobe epilepsy (TLE) with HS is a common cause of refractory epilepsy.

Purpose of the Study:

• To investigate the network of cerebral perfusion changes during CPS in patients with HS.
• To gain insights into the pathophysiology of CPS in the context of HS.
• To explore interrelationships between brain regions exhibiting perfusion changes during seizures.

Main Methods:

• Utilized interictal and ictal single photon emission computed tomography (SPECT) in 24 patients with refractory TLE and HS.
• Performed early injection SPECT during CPS, followed by image normalization and co-registration.
• Employed statistical parametric mapping (SPM99) to identify significant ictal perfusion changes and Pearson correlation coefficients to assess interrelationships.

Main Results:

• Observed ictal hyperperfusion in the ipsilateral temporal lobe, ipsilateral frontal border regions, bilateral occipital lobes, and contralateral postcentral gyrus.
• Detected hypoperfusion in the frontal lobes, contralateral posterior cerebellum, and ipsilateral precuneus.
• Found associations between ipsilateral temporal hyperperfusion and ipsilateral frontal hypoperfusion, and inverse associations with seizure duration.

Conclusions:

• Complex partial seizures in patients with HS involve a widespread network of cerebral perfusion changes.
• Peri-ictal SPECT during a defined window offers a method to analyze cerebral network activity, including excitatory, inhibitory, and gating mechanisms during seizures.
• These findings contribute to a better understanding of seizure dynamics in TLE with HS.