Comparison of the course and key points of the Optic Radiations using dissection and Diffusion Tensor Imaging

Background: Mapping the course of the visual pathways is of great importance for preventing damage to it during neurosurgical operations. Current technology allows certain ways to identify pathways. The pathways of the brain can be mapped in vivo, by using diffusion tensor imaging (DTI). The optic radiations (OR) are susceptible to damage during neurosurgery, therefore there is a need to visualize these in patients prior to surgery. It is important to establish a “safety zone” around the course of the OR and its key points to prevent problems following surgery. In this study, the aim is to compare the course of the OR as determined using dissection and DTI in order to establish such a safety zone. Methods: Four brains were dissected using Klingler’s fiber dissection method, which allowed dissection of the OR. Measurements of these brains and their OR were performed before and after dissection to establish distances from the cortex to the OR. On three of these brains a DTI-scan was performed (before dissection) to determine similar distances. Results: Measurements of the OR were obtained through dissection and correspond to results published in the literature. The same measurements were gained through DTI-scans and correspond with results published in the literature. This resulted in the ability to compare DTI-scans with dissection and also to establish a safety zone. Conclusion: A combination of dissection methods and DTI was used to establish safety boundaries for neurosurgery. Furthermore, by using the two methods a comparison between these two could be made.