A DIRECT COMPARISON OF PET ACTIVATION AND ELECTROCORTICAL STIMULATIONMAPPING FOR LANGUAGE LOCALIZATION

Mapping eloquent language cortex in presurgical patients typically is accomplished using highly invasive direct cortical stimulation techniq ues. Functional imaging during language activation using positron emis sion tomography (PET) is a promising, noninvasive alternative that req uires validation. In seven patients undergoing surgical evaluation for intractable epilepsy, we performed both direct cortical stimulation a nd PET activation mapping of language cortex using identical tasks. MR I, PET, and CT scans were coregistered to directly compare the locatio n of language centers determined by cortical stimulation versus activa tion PET, We found that cortical regions that showed increased cerebra l blood flow during both visual and auditory naming tasks were located in the same regions as subdural electrodes which disrupted language d uring electrical stimulation. Cortical regions underlying electrodes t hat did not disrupt language also showed no consistent changes in regi onal cerebral blood flow during PET activation, Used cautiously, PET a ctivation produces language maps similar to those obtained with direct cortical stimulation, with more complete brain coverage and considera bly less invasion.