Detection of Epileptogenic Zones in Tuberous Sclerosis Complex Using Voxel Analysis of AMT and FDG PET Scanning.
Abstract number :
2.199
Submission category :
Year :
2001
Submission ID :
292
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
E. Asano, MD, Pediatrics and Neurology; C. Husk, BS, Pediatrics; O. Muzik, PhD, Pediatrics and Radiology; C. Shen, PhD, Radiology; A. Shah, MD, Neurology; J. Shah, MD, Neurology; A. Canady, MD, Neurosurgery; H.T. Chugani, MD, Pediatrics, Neurology and Rad
RATIONALE: We have shown previously that region of interest (ROI) analysis of MRI and alpha-[11C]methyl-L-tryptophan (AMT) PET scans can identify epileptogenic tubers (increased uptake) in 2/3 of patients with tuberous sclerosis complex (TSC), while 2-deoxy-2-[18F]fluoro-D-glucose (FDG) PET shows decreased glucose metabolism in tubers and other cortical lesions, regardless of epileptogenicity. In the present study, we have developed a new method of voxel analysis using PET scans of AMT and FDG for detecting presumed epileptogenic zones, based on the hypothesis that epileptogenic lesions show decreased FDG uptake and increased AMT uptake.
METHODS: Eighteen children (mean age 7.5 years old) were studied. Patients underwent EEG, MRI and PET scans of AMT and FDG. Subsequently, the two PET images were co-registered. The co-registered images were then processed to obtain the ratio of AMT uptake to FDG uptake for each voxel in the image volume. Regions with increased ratio of these two compounds were visually defined and decided as presumed epileptogenic zones. Finally, receiver operator characteristics analysis was performed, to compare the sensitivity and specificity of ROI analysis versus voxel ratio analysis for concordance to the EEG focus.
RESULTS: Using the voxel ratio analysis, fourteen patients showed at least one region with increased ratio of AMT to FDG uptake corresponding to the EEG focus. Identified regions frequently included not only tubers but also adjacent cortex. The sensitivity was found to be 0.74 for voxel analysis and 0.78 for ROI analysis. The specificity was found to be 0.97 for voxel analysis and 0.78 for ROI analysis (p=0.002).
CONCLUSIONS: The voxel ratio analysis is significantly more specific than conventional ROI analysis. Therefore, we suggest that interictal AMT PET combined with FDG PET will improve the detection of epileptogenic zones in TSC patients being evaluated for epilepsy surgery.[figure]
Support: NIH NS38324; National Tuberous Sclerosis Association