Sensitivity and specificity of quantitative difference SPECT analysis in seizure localization

Area of Science:

• Neurology
• Medical Imaging
• Epilepsy Research

Background:

• True ictal SPECT accurately shows perfusion increases in the epileptogenic zone but requires immediate injection during seizures.
• Investigating perfusion changes via ictal or postictal SPECT is crucial for localizing the epileptogenic region in refractory partial epilepsy.

Purpose of the Study:

• To evaluate the effectiveness of ictal or immediate postictal SPECT perfusion changes in localizing the epileptogenic region in patients with refractory partial epilepsy.

Main Methods:

• Quantitative perfusion difference images were computed by registering, normalizing, and subtracting interictal SPECT from ictal/postictal SPECT in 53 patients.
• SPECT subtraction results were compared against visually interpreted SPECT, scalp EEG, MRI, PET, and intracranial EEG.

Main Results:

• Perfusion changes were noted in 81% of patients (increased with ictal, decreased with postictal injections).
• SPECT subtraction analysis demonstrated 86% sensitivity and 75% specificity compared to intracranial EEG.
• SPECT subtraction outperformed other noninvasive methods like scalp EEG, MRI, and PET in localization.

Conclusions:

• SPECT perfusion difference analysis is a highly sensitive and specific noninvasive method for localizing epileptogenic regions.
• Its accuracy is comparable to intracranial EEG, making it a valuable tool in epilepsy management.
• Precise timing of SPECT injection relative to seizure occurrence is essential for optimal results.