Preoperative functional magnetic resonance imaging assessment of higher-order cognitive function in patients undergoing surgery for brain tumors

Object. Resection of brain tumors has been shown to increase patient survival. The extent of the possible resection, however, depends on whether the tumor has invaded brain regions important for motor, sensory, or cognitive processes and whether the brain tissue surrounding the tumor maintains its functional role. The goal of the present Study was to develop new pre- and intraoperative tools to specifically assess the function of the rostral part of the dorsal premotor cortex (PMdr) in 4 patients with brain tumors close to this region. Methods. Using functional magnetic resonance (fMR) imaging and a task developed to assess accurate selection between competing responses based on conditional rules, the authors preoperatively assessed the function of the PMdr in 4 patients with brain tumors close to this region. In 1 patient, the authors developed an intraoperative procedure to assess performance on the task during the tumor resection. Results. Preoperative fMR imaging data showed specific activity increases in the vicinity of the tumors, that is, in the PMdr. As confirmed by postoperative structural MR imaging, the extent of the tumor resection was optimal and the functional region within the PMdr was preserved. Furthermore, patients exhibited no postoperative deficits during task performance, demonstrating that the function was preserved. Intraoperative behavioral results demonstrated that the cognitive processes underlying performance on the task remained intact throughout the tumor resection. Conclusions. These findings suggest that preoperative fMR imaging, together with intraoperative behavioral evaluation, may be a useful paradigm to assist neurosurgeons in preserving cognitive function in patients with brain tumors.