Subcortical motor mapping: what DTI tractography adds to intraoperative monitoring.

Surgical treatment for lesions located within or in close proximity of motor areas or pathways requires the identification and preservation of functional cortical and subcortical sites. DTI (diffusion tensor imaging) fiber tracking is a novel technique in MR which allows the identification of white matter tracts and to establish the relationship of the reconstructed tracts with the tumor mass. In this work we described our experience on the use of DTI fiber tracking for motor pathways in series of patients with low or high grade gliomas, who were subsequently submitted to surgery for tumor removal. DTI fiber tracking was incorporated in the presurgical procedures, and used either in the presurgical planning or during surgery, in combination with subcortical mapping. The usefulness of the technique and the actual limitations encountered when it is associated with subcortical motor mapping at the time of surgery are described and discussed.