Presurgical Multimodal Imaging in Patients with Cerebral Tumors

We introduce a concept for presurgical localization of speech and motor function, which we apply to patients with brain tumors located near eloquent cortex regions. By using standard hard- and software which enables the coregistration of brain structure, amino acid uptake and brain function into one stereotactic dataset, a refined planning of tumor surgery is feasible. The cortical localization for finger-tapping and syntactic speech processing with fMRI (block design, TR time 4000 ms, FOV 200mm, 30 slices à 4mm each frame, gap 0.4mm) is based on two recently validated paradigms. PET imaging is done using the amino acid-tracer fluoroethyltyrosine (FET) which shows an uptake in vital brain tumor tissue. The structural dataset is a 3D high-resolution MRI of each patient consisting of 160 sagitttally acquired slices in a 256×256 matrix, allowing us to compute isotropic voxels with a size of 1×1×1mm. So far, 11 patients (9 males, 2 females, age 40±12 years) have been studied. Thereof 7 patients with a left-hemispheric fronto-temporal tumor were studied with speech activation and FET-PET. To highlight our approach, we describe the case of a 33-year-old right-handed woman with a left-hemispheric astrocytoma WHO II who presented with an acute speech arrest followed by a generalized tonic-clonic-seizure. The clinical-neurological findings disclosed a latent hemiparesis on the right side. During the neuropsychological testing the patient achieved throughout normal percent ranks in all applied tests [Rivermead Behavioural Memory Test (RBMT immediate recall 48.5%, delayed recall 63.6%), Wechsler digit-span (forward 95%, backward 26%), Wechsler block-span (forward 43%, backward 19%), verbal fluency (category „forenames“ 85%), „Token Test“ from the AAT faultless]. The structural MR imaging showed a hypointense lesion in the fronto-central junction of the left hemisphere involving the left frontal operculum showing a focal uptake of FET in the dorsal part of the tumor. FMRI revealed an anterior displacement of the frontal speech area and a posterior displacement of the presumed posterior speech area. In addition, there were abnormal activations in a mirror-like fashion in the right cerebral hemisphere.