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Six patients with brain tumors within or near the primary motor cortex underwent preoperative functional magnetic resonance imaging (fMRI) and intraoperative cortical mapping, and the accuracy of those techniques for localization of the primary motor cortex and motor function beside the tumor were determined by comparison against neuroanatomical correlates from pre-, intra- and postoperative neurological observations. The location of the primary motor cortex was detected by intraoperative cortical mapping in 5 of 6 cases and by fMRI in all 6 cases. Brain mapping provided equivocal information on the cortical representation of motor territories, and with the technique used in close proximity to the tumor, the motor territories were not detected in all but 1 case. In contrast, the areas controlling motor function in close proximity to the tumor were detected by fMRI in 4 of 6 cases. These data indicate that intraoperative cortical mapping has a low sensitivity for the detection of motor function in the area beside the tumor. Therefore, this technique may not be sufficient to prevent compromise of motor areas during tumor resection., (Copyright 2005 S. Karger AG, Basel.)

Magnetic source imaging (MSI) combines the unique spatial and temporal functional accuracy of magnetoencephalography (MEG) with the anatomic and pathologic detail of magnetic resonance (MR). This relatively new method of evaluating brain function provides a preoperative mapping of brain function and brain structure by integrating the functional information of MEG with the structural information of MR. This results in data on actual neuronal interactions in clinical patients. The temporal and spatial accuracy of the MEG data, combined with the anatomic and pathologic specificity of MRI, results in the magnetic source image, which offers accurate knowledge of cortical functional organization, and is important in the surgical treatment of brain neoplasms, vascular malformations, and epilepsy. MSI allows the tracking of neuronal activity on the scale of milliseconds with millimeter accuracy, and continues to lead to new understanding of many functional brain disorders.

The clinical and pathological report presents a seven-week old girl suffering from signs of raised ICP. A ventriculo-atrial shunt was inserted and replaced by a ventriculo-abdominal shunt due to occlusion at 15 months of age. At 16 months, craniotomy and resection of an oligodendroglioma was performed and the shunt was preserved. The child died at 18 months due to extensive local recurrence. Autopsy revealed massive peritoneal metastases of the tumor. This is the eleventh published case of canalicular metastases of glioma.