Presurgical functional mapping with functional MRI

The present article describes current indications for functional MRI in the preoperative planning of neurosurgical patients. Functional MRI continues to have an expanding role.

There are three main categories of patients who commonly undergo preoperative functional MRI. Patients with lesions close to eloquent cortex can benefit from preoperative functional MRI to assess resectability and reduce the possibility of functional deficit. The second group are those patients who have functional MRI as part of their preoperative planning to localize language dominance and for functional localization of memory. The final group are those patients in whom attempts are made to image and localize abnormal brain function. This has a specific application in the field of epilepsy surgery (electroencephalographic-correlated functional MRI). These three roles require different spatial resolutions. Advances in multimodality imaging are enabling more accurate localization of function intraoperatively.

It is hoped that the increasing use of functional MRI in combination with both preoperative and intraoperative imaging modalities may reduce the risk of neurological deficit while improving completeness of resection. Electroencephalographic-correlated functional MRI may provide an additional method for localization of epileptogenic foci.