Regional Positron Emission Tomography (PET) Hypometabolism and Temporal Lobe Volumes (TLVs) in Patients with Intractable Temporal Lobe Epilepsy (TLE) Due to Hippocampal Sclerosis (HS) and HS Associated with Cortical Dysplasia (CD).
Abstract number :
1.214
Submission category :
Year :
2001
Submission ID :
297
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
B. Diehl, MD, Neurology, Cleveland Clinic Foundation, Cleveland, OH; S. Rona, MD, Neurology, Cleveland Clinic Foundation, Cleveland, OH; E. LaPresto, MS, Neurosurgery, Cleveland Clinic Foundation, Cleveland, OH; P. Ruggieri, MD, Radiology, Cleveland Clini
RATIONALE: Medically intractable temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS, with or without cortical dysplasia, CD) is associated with various imaging characteristics including atrophy of the hippocampal formation and regional FDG-PET hypometabolism The goal of the study is to correlate MRI-based temporal lobe volume with the presence of PET hypometabolism in patients who underwent anterior temporal resection for the treatment of drug resistant TLE.
METHODS: 23 patients with medically intractable temporal lobe epilepsy (right TLE n= 12, left TLE n=11) who underwent en bloc resection of the mesial and antero-lateral neocortical structures and had good outcome were included in the study. The diagnosis of HS (hippocampal cell loss [gt]30%) was confirmed in all patients. Associated neocortical CD that is characterized by architectural disorganization and the presence of dysmorphic neurons was found in 13 patients. Temporal lobe volumes (TLV[scquote]s) were measured, MRI and PET co-registered and regions of interest (ROI[scquote]s) were determined as gray matter of the mesial, lateral and anterior temporal lobe. Mean ROI counts ipsilateral to the epileptogenic zone were compared to the contralateral corresponding ROI and correlations between TLV and PET asymmetries were performed
RESULTS: Overall, patients with HS (with or without CD) had significant ipsilateral PET hypometabolism in all 3 regions studied (P[lt]0.0001). TLVs were also significantly smaller on the epileptogenic side (P[lt]0.05). The PET asymmetries ipsilateral/contralateral to the epileptogenic zone and TLV asymmetries correlated significantly for the lateral temporal lobes (P[lt]0.05). Patients with HS+CD and temporal lobe atrophy had more prominent PET hypometabolism in the anterior and lateral temporal regions as compared to patients with isolated HS (P[lt]0.05). Mesial temporal hypometabolism was comparable between the two groups.
CONCLUSIONS: The presence of microscopic CD in the setting of hippocampal sclerosis and temporal lobe atrophy is associated with more diffuse and prominent anterior and lateral temporal metabolism dysfunction. The prognostic significance of these findings is unknown as all patients had anterior temporal lobe resection and were seizure free. Further studies are needed to confirm these findings and to correlate the PET hypometabolism patterns with electroencephalographic and outcome data in patients operated on for HS with or without CD.