Magnetic source imaging supports clinical decision making in glioma patients

Objective: This study addresses the potential utility of preoperative functional imaging with magnetoencephalography (MEG) for the selection of glioma patients who are likely to benefit from resective surgical treatment regarding postoperative morbidity. Methods: One hundred and nineteen patients with gliomas adjacent to sensorimotor, visual and speech related brain areas were investigated preoperatively with a MAGNES II biomagnetometer. In each patient the pre-surgical evaluation was focussed on the visual, sensorimotor cortex and/or of the speech related brain areas. A grading system was then used according to the distance of the MEG activation sources to the nearest tumour border to determine the further treatment. The therapeutic options consisted in conservative treatment, stereotactic biopsy and/or a radiation and chemotherapy, substantial cytoreduction and the gross total removal of the lesion. Results: From 119 investigated patients, 55 patients (46.2%) were not considered for surgery due to tumour invasion to functional cortex. Sixty four patients (53.8%) were chosen for resective surgery. In the surgical group only four patients (6.2%) suffered from neurological deterioration. Conclusions: Magnetic source imaging (MSI) proved to be a valuable help in the clinical decision making process of lesions adjacent to functional important brain areas. The relative high number of patients in whom MSI warns of the postoperative crippling sequelae may lead to a better selection of patients who benefit from resective surgery. This method may help to find the patients for whom conservative treatment seems to be more favourable concerning quality of life in the surviving time.