The role of functional imaging in the tumor patient.

Functional imaging studies complement structural magnetic resonance imaging (MRI) in the assessment of patients with brain tumor-associated focal epilepsy. (11)C-Methionine (MET) and (18) F-fluoro-ethyl-L-tyrosine (FET) are amino acid analogues that highlight metabolically active areas in positron emission tomography (PET). Ictal single photon emission computed tomography (SPECT) can provide information about perilesional areas of seizure onset and early propagation. Functional MRI (fMRI) and diffusion tensor imaging (DTI) allow noninvasive identification of potentially eloquent motor, sensory, and language cortical areas and pathways with an accuracy of 10-15 mm compared to electrocortical stimulation (ECS). Repetitive navigated transcranial magnetic stimulation (TMS) allows even more precise noninvasive delineation of primary motor cortex. Information from functional imaging studies helps in the planning of brain tumor biopsies, resections, and the planning of intracranial video-electroencephalography (EEG) studies.