Application of spectroscopic imaging in epilepsy

Area of Science:

• Neuroscience
• Medical Imaging
• Biochemistry

Background:

• Functional and anatomical neuroimaging significantly impacts the evaluation of patients for epilepsy surgery.
• Positron Emission Tomography (PET) demonstrated interictal metabolic abnormalities in the epileptogenic focus, increasing surgical candidacy and reducing the need for invasive intracranial electrode evaluations.

Purpose of the Study:

• To evaluate the utility of Magnetic Resonance Spectroscopy (MRS) in identifying and localizing seizure foci.
• To correlate metabolic changes detected by MRS with epilepsy localization and severity.

Main Methods:

• Utilized single voxel and whole brain 1H and 31P MRS imaging techniques.
• Analyzed metabolic changes including inorganic phosphate (Pi), pH, phosphomonoesters (PME), and N-acetylaspartate (NAA).
• Correlated MRS findings with anatomical measures like hippocampal atrophy and cell loss.

Main Results:

• Interictal MRS showed characteristic metabolic changes: increased Pi, elevated pH, and decreased PME and NAA in the epileptogenic focus.
• MRS accurately lateralized temporal and frontal lobe epilepsy.
• Decreased NAA concentrations correlated with cell loss severity and may indicate the seizure onset zone, even when changes are widespread.

Conclusions:

• MRS detects abnormal metabolic activity and asymmetry patterns in focal epilepsy, useful for seizure localization.
• Metabolic findings from MRS can guide patient selection for epilepsy surgery and potentially reduce the need for invasive monitoring.
• MRS offers a non-invasive method to assess metabolic dysfunction associated with epilepsy.