149 - Diffusion Tensor Imaging-Informed Dissection of Human White Matter Tracts to Create Three-Dimensional Computer-Generated Models

Poster Board Number: 149
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Abstract Body : White matter (WM) tracts are the anatomical basis for the vast functional network of the human brain. Diffusion tensor imaging (DTI) techniques allow insight into this structural connectivity of the WM tracts, which have been mapped with great precision and accuracy. Given the importance of WM tracts in neurological disorders such as Multiple Sclerosis and concussions, an intricate understanding of WM anatomy is critical for medical students. In situ cross-sectional brain slices that are used in anatomy education provide little information on the three-dimensional spatial characteristics of these fibers. We set out to combine DTI data with WM fiber tract dissection to develop an interactive 3D educational tool.

DTI models were studied in detail to identify the target fiber tracts and the landmarks associated with them. The target fiber tracts were divided into three groups: 1) lateral superficial tracts, 2) lateral deep tracts, and 3) medial tracts. Two formalin-fixed human brains were used for the dissections. On the first iteration, two separate dissections were performed on each hemisphere to isolate the lateral superficial and lateral deep fiber tracts respectively. The dissected specimen was then 3D scanned using an Artec Spider surface scanner (Artec Studio 15) and photogrammetry (Adobe Lightroom, Adobe Photoshop, and RealityCapture). The 3D model was superimposed with the DTI data (3DSlicer and Blender), to identify the errors of dissection and inform the approach to the second dissection. The first specimen was then partially hemisected to identify and isolate the medial fiber tracts. On the second dissection, the DTI-superimposed 3D model was used as a guide to identify and isolate the target fiber tracts with greater precision and accuracy. The final prosections were captured using similar techniques to generate a high-quality interactive 3D model of human WM tracts.

Two human WM prosections and their respective interactive 3D models were produced. In the first model, the Superior and inferior longitudinal fasciculi, the arcuate fasciculus, the uncinate, and corona radiata were identified on the hemisphere with superficial dissections, and the external and internal capsules, and the optic radiation were identified on the hemisphere with deep dissections. The medial tracts including the cingulum, fornix, anterior commissure, and frontocaudal fibers were also successfully isolated and identified.

DTI data can be used to guide and increase the accuracy of WM fiber tract dissection in human brains. These datasets can then be turned into 3D models superimposed with DTI data, to be used as an interactive educational resource.

The interactive 3D models generated in this study allow the user to extrapolate the path of the dissected tracts to their destinations and appreciate the interconnectivity of the fiber tracts in three-dimensional space. In the next step, we aim to develop a protocol for using augmented reality for real-time feedback during WM dissection.