The validity of 3 Tesla motor functional magnetic resonance imaging (fMRI) in patients with gliomas involving the primary motor cortex was investigated by intraoperative navigated motor cortex stimulation (MCS). Methods: Twenty two patients (10 males, 12 females, mean age 39 years, range 10-65 years) underwent preoperative fMRI studies, performing motor tasks including hand, foot, and mouth movements. A recently developed high field clinical fMRI technique was used to generate pre-surgical maps of functional high risk areas defining a motor focus. Motor foci were tested for validity by intraoperative motor cortex stimulation (MCS) employing image fusion and neuronavigation. Clinical outcome was assessed using the Modified Rankin Scale. Results: FMRI motor foci were successfully detected in all patients preoperatively. In 17 of 22 patients (77.3%), a successful stimulation of the primary motor cortex was possible. All 17 correlated patients showed 100% agreement on MCS and fMRI motor focus within 10 mm. Technical problems during stimulation occurred in three patients (13.6%), no motor response was elicited in two (9.1%), and MCS induced seizures occurred in three (13.6%). Combined fMRI and MCS mapping results allowed large resections in 20 patients (91%) (gross total in nine (41%), subtotal in 11 (50%)) and biopsy in two patients (9%). Pathology revealed seven low grade and 15 high grade gliomas. Mild to moderate transient neurological deterioration occurred in six patients, and a severe hemiparesis in one. All patients recovered within 3 months (31.8% transient, 0% permanent morbidity). Conclusions: The validation of clinically optimised high magnetic field motor fMRI confirms high reliability as a preoperative and intraoperative adjunct in glioma patients selected for surgery within or adjacent to the motor cortex.

Efficacy and tolerability of levetiracetam (LEV) as perioperative seizure prophylaxis in supratentorial brain tumor patients were retrospectively studied. Between February 2007 and April 2009 in a single institution, 78 patients with primary or secondary supratentorial brain tumors [40 female, 38 male; mean age 57 years, from 27 to 89 years; gliomas in 42 patients (53.8%), brain metastases in 17 (21.8%), meningiomas in 16 (20.5%), 1 primary central nervous system (CNS) lymphoma patient, and 2 patients with radiation necrosis] received between 1,000 mg and 3,000 mg LEV perioperatively. Preoperatively, 30 patients had experienced seizures (38.5%), most commonly glioma patients (47.6%), but also meningioma patients (31.3%) or patients with brain metastases (23.5%). No more seizures occurred in patients receiving 1-3 g LEV preoperatively. Within the first week postoperatively, a single seizure occurred in two patients (2.6%). At the end of the follow-up period (mean 10.5 months, range 0-31 months), 71 of the 78 patients (91%) were seizure free and 21 (26%) patients were not taking antiepileptic drugs. We observed side-effects in five patients (6.4%), including non-tumor-associated progressive somnolence in three patients (1.5 g, 1.5 g, and 2 g LEV daily) and reactive psychosis in two patients (1 and 1.5 g LEV daily), regressing after dose reduction. Perioperative LEV in supratentorial brain tumor patients was well tolerated. Compared with the literature, it resulted in low (2.6%) [corrected] seizure frequency in the early postoperative period. Additionally, its advantage of lacking cytochrome P450 enzyme induction allowed early initiation of effective postoperative chemotherapy in malignant glioma patients.

This study aims at a comparative evaluation of two recently introduced electromagnetic tracking systems under reproducible simulated operating-room (OR) conditions: the recently launched Medtronic StealthStation, Treon-EM and the NDI Aurora. We investigate if and to what extent these systems provide improved performance and stability in the presence of surgical instruments as possible sources of distortions compared with earlier reports on electromagnetic tracking technology. To investigate possible distortions under pseudo-realistic OR conditions, a large Langenbeck hook, a dental drill with its handle and an ultrasonic (US) scanhead are fixed on a special measurement rack at variable distances from the navigation sensor. The position measurements made by the Treon-EM were least affected by the presence of the instruments. The lengths of the mean deviation vectors were 0.21 mm for the Langenbeck hook, 0.23 mm for the drill with handle and 0.56 mm for the US scanhead. The Aurora was influenced by the three sources of distortion to a higher degree. A mean deviation vector of 1.44 mm length was observed in the vicinity of the Langenbeck hook, 0.53 mm length with the drill and 2.37 mm due to the US scanhead. The maximum of the root mean squared error (RMSE) for all coordinates in the presence of the Langenbeck hook was 0.3 mm for the Treon and 2.1 mm for the Aurora; the drill caused a maximum RMSE of 0.2 mm with the Treon and 1.2 mm with the Aurora. In the presence of the US scanhead, the maximum RMSE was 1.4 mm for the Treon and 5.1 mm for the Aurora. The new generation of electromagnetic tracking systems has significantly improved compared to common systems that were available in the middle of the 1990s and has reached a high level of technical development. We conclude that, in general, both systems are suitable for routine clinical application.

Residual faint 5ALA uptake is documented in large areas at the end of GBM resection and corresponds to tumor infiltration. These 5-ALA positive resection plans exceeded the (18)F-FET uptake areas in postoperative PET scans. Thus, intraoperative 5-ALA residual fluorescence seems to be a more sensitive marker than (18)F-FET PET for residual tumor in malignant gliomas.

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