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Background: Results of awake craniotomy are compared to results of resections done under general anesthesia in patients operated with IMRI control. We hypothesized that stimulation of the cortex and white matter during awake surgery supplements IMRI control allowing for safer resection of eloquent brain area tumors., Methods: The study group consisted of 20 consecutive patients undergoing awake craniotomy with IMRI control. Resection outcome of these patients was compared to a control group of 20 patients operated in the same IMRI suite but under general anesthesia without cortical stimulation. The control group was composed of those patients whose age, sex, tumor location, recurrence and histology best matched to patients in study group., Results: Cortical stimulation identified functional cortex in eight patients (40 %). Postoperatively the neurological condition in 16 patients (80 %) in the study group was unchanged or improved compared with 13 patients (65 %) in the control group. In both groups, three patients (15 %) had transient impairment symptoms. There was one patient (5 %) with permanent neurological impairment in the study group compared to four patients (20 %) in the control group. These differences between groups were not statistically significant. There was no surgical mortality in either group and the overall infection rate was 5 %. Mean operation time was 4 h 45 min in the study group and 3 h 15 min in the control group., Conclusions: The study consisted of a limited patient series, but it implies that awake craniotomy with bipolar cortical stimulation may help to reduce the risk of postoperative impairment following resection of tumors located in or near speech and motor areas also under IMRI control.

Rationale and Objectives: Minimally invasive neurosurgery requires methods to specify surgical boundaries of target tissue, such as brain tumors. This study investigated technical possibilities and clinical usefulness of adapting edema attenuated inversion recovery (EDAIR) pulse sequences to suppress magnetic resonance signal from cerebral edema in brain tumor patients. Materials and Methods: A resistive 0.23-T magnetic resonance scanner with magnitude-encoded inversion recovery sequences was used. Twenty-eight separate scanning tests in 25 neurosurgical brain tumor patients were performed on the day before surgery. An inversion recovery sequence with several inversion times between 150 and 2,200 ms was tested. The same sequences were also used intraoperatively and postoperatively. Results: T1 relaxation time of brain edema varied from case to case. An inversion recovery sequence with an inversion time of 400–800 milliseconds attenuated brain edema and seemed to help in demarcating gross brain tumor for surgical resection. These features were helpful for the evaluation of resectable tumor tissue particularly using neuronavigation techniques. Conclusions: According to these preliminary findings, inversion recovery sequences supplement other imaging modalities and assist neurosurgeons in evaluating different surgical trajectories and in estimating brain tumor volume before craniotomy. [Copyright &y& Elsevier]