Preoperative assessment of the cerebral hemispheric dominance for language with CBF PET

This study evaluated whether cerebral blood flow positron emission tomography (CBF PET) could provide assessments of language dominance comparable to the invasive reference method, the Wada test (selective intracarotid injection of amytal with cognitive testing subsequent to the anesthesia of each hemisphere). In 9 of 11 patients with partial complex epilepsy who were operative candidates, the Wada test lateralized unequivocally; in two subjects Wasa results were indeterminate (no speech arrest following injection of either carotid). Of four brain regions selected a priori for PET analysis based on techniques developed from studies of normal volunteers, anterior frontal cortex (AFC) was most consistently detectable and lateralized. AFC laterality agreed with Wada laterality in eight of the nine subjects lateralized by Wada. In both subjects having an indeterminate Wada, PET demonstrated clear laterality. In one subject both PET and Wada lateralized, but in disagreement; anterior temporal lobectomy in the hemisphere indicated by PET as language‐dominant caused long‐lasting language impairment. We conclude that CBF PET: (1) provides an effective, noninvasive adjunct to the Wada test; and (2) permits assessment of language dominance in normal research volunteers. © 1993 Wiley‐Liss, Inc.