SPECT in focal epilepsies.

Area of Science:

• Neuroimaging
• Epileptology
• Nuclear Medicine

Background:

• Brain perfusion changes during seizures have been noted since the 1930s.
• Single Photon Emission Computed Tomography (SPECT) emerged in the 1970s, with regional cerebral perfusion (rCP) tracers available in the 1980s.
• Initial SPECT studies focused on interictal hypoperfusion, particularly in temporal lobe epilepsies.

Purpose of the Study:

• To investigate the utility of SPECT in characterizing ictal and postictal brain perfusion changes.
• To demonstrate how SPECT findings can aid in localizing the epileptogenic zone for surgical planning.
• To explore the application of SPECT in studying neuroreceptor abnormalities and brain function during specific tests.

Main Methods:

• Utilizing SPECT with tracers like hexamethyl propyleneamine oxime (HMPAO) to assess regional cerebral perfusion (rCP) during seizures.
• Analyzing perfusion patterns during the ictal, postictal, and interictal phases of various epilepsy types.
• Employing numerical analysis techniques, such as statistical parametric mapping, for image analysis.

Main Results:

• SPECT demonstrated significant increases in temporal lobe perfusion during ictal phases of mesial temporal lobe epilepsy.
• Postictal phases showed a characteristic sequence of hypoperfusion, initially in the lateral and then the mesial temporal lobe.
• Varied perfusion changes were observed in seizures originating from different brain structures, and localized abnormalities were seen in neuroreceptor studies.

Conclusions:

• SPECT is a valuable tool for understanding dynamic brain perfusion changes during seizures.
• SPECT imaging aids in the practical localization of the epileptogenic zone, supporting surgical intervention planning.
• Advanced analysis techniques like statistical parametric mapping enhance the diagnostic yield of SPECT in epilepsy.