Three-dimensional visualization of the pyramidal tract in a neuronavigation system during brain tumor surgery: First experiences and technical note

OBJECTIVE: To integrate spatial three-dimensional information concerning th e pyramidal tracts into a customized system for frameless neuronavigation d uring brain tumor surgery. METHODS: Four consecutive patients with intracranial tumors in eloquent are as underwent diffusion-weighted and anatomic magnetic resonance imaging stu dies within 48 hours before surgery. Diffusion-weighted datasets were merge d with anatomic data for navigation purposes. The pyramidal tracts were seg mented and reconstructed for three-dimensional visualization. The reconstru ction results, together with the fused-image dataset, were available during surgery in the environment of a customized neuronavigation system. RESULTS: In all four patients, the combination of reconstructed data and fu sed images was a helpful additional source of information concerning the tu mor seat and topographical interaction with the pyramidal tract. In two pat ients, intraoperative motor cortex stimulation verified the tumor seat with regard to the precentral gyrus. CONCLUSION: Diffusion-weighted magnetic resonance imaging allows individual estimation of large fiber tracts applicable as important information in in traoperative neuronavigation and in planning brain tumor resection. A three -dimensional representation of fibers associated with the pyramidal tract d uring brain tumor surgery is feasible with the presented technique and is a helpful adjunct for the neurosurgeon. The main drawbacks include the lengt h of time required for the segmentation procedure, the lack of direct intra operative control of the pyramidal tract position, and brain shift. However , mapping of large fiber tracts and its intraoperative use for neuronavigat ion have the potential to increase the safety of neurosurgical procedures a nd to reduce surgical morbidity.