Intraoperative validation of functional magnetic resonance imaging and cortical reorganization patterns in patients with brain tumors involving the primary motor cortex

Object. The purpose of the present study was to compare the results of func tional magnetic resonance (fMR) imaging with those of intraoperative cortic al stimulation in patients who harbored tumors close to or involving the pr imary motor area and to assess the usefulness of fMR imaging in the objecti ve evaluation of motor function as part of the surgical strategy in the tre atment of these patients. Methods. A total of ii consecutive patients, whose tumors were close to or involving the central region, underwent presurgical blood oxygen level-depe ndent fMR imaging while performing a motor paradigm that required them to c lench and spread their hands contra- and ipsilateral to the tumor. Statisti cal cross-correlation functional maps covering the primary and secondary mo tor cortical areas were generated and overlaid onto high-resolution anatomi cal MR images. Intraoperative electrical cortical stimulation was performed to validate the presurgical fMR imaging findings. In nine (82%) of 11 pati ents, the anatomical fMR imaging localization of motor areas could be verif ied by intraoperative electrical cortical stimulation. In seven patients tw o or more activation sites were demonstrated on fMR imaging, which were con sidered a consequence of reorganization phenomena of the motor cortex: cont ralateral primary motor area (nine patients), contralateral premotor area ( four patients), ipsilateral primary motor area (two patients), and ipsilate ral premotor area (four patients). Conclusions. Functional MR imaging can be used to perform objective evaluat ion of motor function and surgical planning in patients who harbor lesions near or involving the primary motor cortex. Correlation between fMR imaging findings and the results of direct electrical brain stimulation is high, a lthough not 100%. Based on their study, the authors believe that cortical r eorganization patterns of motor areas might explain the differences in moto r function and the diversity of postoperative motor function among patients with central tumors.