Open MRI-guided microsurgery of intracranial tumours in or near eloquent brain areas

Objectives: preservation of brain function while maximizing resection is the main aim of brain tumor surgery. The purpose of this study was to evaluate the efficacy of intra-operative magnetic resonance imaging to preserve brain function in patients with tumors in or near eloquent brain areas. Methods and Material: between August 1997 and January 1999 fifty-eight craniotomies for intracranial tumors or vascular malformations have been performed at the University of Leipzig using a 0.5 T superconducting MR system 'SIGNA SF' (General Electric Medical Systems, USA). In 32 of these patients (15 male/ 17 female) with intracranial tumors, located in or near eloquent brain areas (sensorimotor cortex/speech center), 34 craniotomies were performed using the image guidance of the interventional MRI. Results: using intra-operative MRI criteria, complete tumor removal could be achieved in 28 (82 %) of 34 procedures. In 3 patients only subtotal tumor removal was possible, because the residual tumor was not visible on the intra-operative MR images, but could be identified on early diagnostic follow-up MR-scans. In 3 patients, incomplete tumor resection was performed in order to avoid neurological impairment. In these patients intra-operative MR-Images revealed residual tissue abnormalities involving or encroaching on deep brain structures or motor/language cortex. Pre-operative neurological status was unchanged in 24 patients (70 %), worsened in 4 patients (12 %) and improved in 6 patients (18 %). Conclusions. Intra-operative MRI is helpful for navigation as well as to demonstrate the tumor margins to achieve a complete and safe resection of intracranial lesions located in or near eloquent brain areas. It enables an image based functional monitoring of the brain which is critical for motor, sensory or language function. Complications related to the surgical procedure are reduced and the risk of neurological deterioration due to tumor removal and postoperative complications is minimized. (author)