SINGLE-VOXEL PROTON MR SPECTROSCOPY AND POSITRON-EMISSION-TOMOGRAPHY FOR LATERALIZATION OF REFRACTORY TEMPORAL-LOBE EPILEPSY

PURPOSE: We compared the metabolic information obtained from single-vo xel proton MR spectroscopy and positron emission tomography (PET) in p atients with temporal lobe epilepsy. METHODS: Twenty-nine patients,vit h temporal lobe epilepsy were screened for metabolic abnormalities wit h both proton MR spectroscopy and PET. Lateralization with MR spectros copy was possible by using NAA/(Cho+Cr) and an asymmetry index. Hypome tabolism as determined by PET was classified as typical or complex. RE SULTS: Twenty-four (96%) of 25 patients whose seizure onset could be l ateralized to one temporal lobe showed ipsilateral lateralization with either MR spectroscopy or PET, whereas concordant lateralization with both techniques was possible only in 14 (56%) of the 25 patients. MR spectroscopy showed 42 abnormal temporal lobes whereas PET showed only 25 lobes with decreased metabolism. All temporal lobes with hypometab olism at PET also had a low NAA/(Cho+Cr). Five patients (20%) with neg ative PET studies had seizures lateralized correctly with MR spectrosc opy. CONCLUSION: Proton MR spectroscopy is more sensitive in depicting metabolic abnormalities than is PET in patients with temporal lobe ep ilepsy. Patients with negative PET studies will benefit from MR spectr oscopy for the purpose of lateralization.