Magnetic resonance imaging in intractable partial epilepsy: correlative studies

Area of Science:

• Neurology
• Radiology
• Neuroimaging

Background:

• Intractable complex partial seizures often lack clear abnormalities on computed tomographic (CT) scans.
• Evaluating diagnostic imaging modalities is crucial for identifying the etiology of epilepsy.

Purpose of the Study:

• To evaluate the utility of magnetic resonance imaging (MRI) in detecting epileptogenic lesions in patients with complex partial seizures and normal CT findings.
• To compare MRI findings with positron emission tomography (PET) and electroencephalography (EEG).

Main Methods:

• MRI was performed on 35 patients with intractable complex partial seizures and normal CT scans.
• Results were correlated with PET scans, EEG ictal onset, and pathological examination.
• Specific lesion types (tuberous sclerosis, astrocytomas, hamartomas, mesial temporal sclerosis) were assessed.

Main Results:

• MRI identified epileptogenic structural lesions in 7 patients, including tuberous sclerosis, astrocytomas, and hamartomas.
• PET scans were normal in 3 patients with MRI-detected lesions.
• Of 18 patients with mesial temporal sclerosis, 10 showed temporal lobe hypometabolism on PET, despite normal MRI findings.

Conclusions:

• MRI offers valuable diagnostic information for detecting nonsclerotic epileptogenic lesions in the temporal lobe.
• MRI complements CT and PET imaging in the etiological diagnosis of complex partial seizures.
• MRI can identify structural abnormalities missed by CT and PET in certain epilepsy cases.