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MR and positron emission tomography in the diagnosis of surgically correctable temporal lobe epilepsy
1Department of Radiology, Duke University Medical Center, Durham, NC 27710.
Purpose:
To determine the association of an MR abnormality and a positron emission tomography (PET) abnormality with a good outcome in patients with temporal lobe epilepsy after lobectomy, the association of combined PET and MR findings with good outcomes after lobectomy, and MR and PET pathologic correlation.
Methods:
MR and PET were performed on 27 patients in a blinded study. Histologic studies were correlated with foci of increased T2 signal.
Results:
Increased signal or decreased volume of the hippocampus was noted in 13 of 15 patients with mesial temporal sclerosis. Twelve of 15 had positive PET findings. MR identified 20 (83%) of the 24 patients with good outcomes. PET identified 71%. When MR and PET were combined, they detected 95% of the patients with good outcome. Region of interest measurements of the hippocampus in 11 study patients and 7 control subjects documented a significant increase in signal in the patients with seizures. Histologic correlative studies demonstrated that increased T2 signals related to astrocytosis in the hippocampus and adjacent white matter.
Conclusions:
MR (increased signal and decreased volume of the hippocampus) significantly improved the capability to identify those persons who would be helped by lobectomy. MR sensitivity exceeded that of PET.
Insights
Magnetic resonance imaging (MRI) and positron emission tomography (PET) help predict outcomes after temporal lobe epilepsy surgery. Combining MRI and PET scans accurately identifies patients who will benefit from lobectomy.
Area of Science:
- Neurology
- Neurosurgery
- Radiology
Background:
- Temporal lobe epilepsy (TLE) is a common form of focal epilepsy.
- Surgical intervention, such as lobectomy, can be effective for intractable TLE.
- Predicting surgical outcomes is crucial for patient selection and management.
Purpose of the Study:
- To assess the association of MRI and PET abnormalities with good outcomes after TLE lobectomy.
- To evaluate the combined diagnostic utility of MRI and PET findings.
- To correlate imaging findings with histopathology.
Main Methods:
- A blinded study involving 27 TLE patients undergoing lobectomy.
- Magnetic resonance imaging (MRI) and positron emission tomography (PET) were performed.
- Histopathological examination correlated with imaging findings, particularly increased T2 signal foci.
Main Results:
- MRI identified hippocampal abnormalities (increased signal, decreased volume) in mesial temporal sclerosis.
- MRI detected 83% of good outcomes, while PET identified 71%.
- The combination of MRI and PET detected 95% of patients with good outcomes. Histology confirmed astrocytosis related to increased T2 signals.
Conclusions:
- MRI, particularly hippocampal signal and volume changes, significantly enhances the prediction of positive outcomes from lobectomy.
- MRI demonstrated higher sensitivity than PET in identifying patients who would benefit from surgery.
- Combined imaging modalities offer superior predictive value for TLE surgical success.