NEURON LOSS LOCALIZES HUMAN TEMPORAL-LOBE EPILEPSY BY IN-VIVO PROTON MAGNETIC-RESONANCE SPECTROSCOPIC IMAGING

Temporal lobe epileptogenic foci were blindly localized in 8 patients with medically refractory unilateral complex partial seizures using no ninvasive in vivo proton magnetic resonance spectroscopic imaging (H-1 -MRSI) with 4-ml effective voxel size. The brain proton metabolite sig nals in 8 matched normal controls were bilaterally symmetrical within +/- 10%. The hippocampal seizure foci had 21 +/- 5% less N-acetyl aspa rtate signal than the contralateral hippocampal formations (P < 0.01). The focal N-acetyl aspartate reductions were consistent with patholog y findings of mesial temporal sclerosis with selective neuron loss and gliosis in the surgically resected epileptogenic foci. Proton MRSI co rrectly localized the seizure focus in all 8 cases. By comparison, MR imaging correctly localized 7 of 8 cases and single photon emission co mputed tomography correctly localized 2 of 5 cases. No lactate was det ected in these interictal studies. No significant changes in choline o r creatine were observed. In conclusion,H-1-MRSI is a useful tool for the noninvasive clinical assessment of intractable focal epilepsy. The se preliminary results suggest that H-1-MRSI can accurately localize t emporal lobe epileptogenic foci.