Virtual Dissection of White Matter Tracts in a Human brain using applied Game Design and Virtual Reality imaging

Visualisation of neural tracts in the human brain has previously been accomplished using two dimensional (2D) representational formats. In most cases, pre-operative visualisation is through the medium of 2D MRI image slices, representing coordinates in the brain through a combination of axial, sagittal, and coronal orthographic viewpoints. Software such as ExploreDTI can visualise off-axis viewpoints, however this method is limited to 2.5D image representations. The use of such 2D representations can require significant training in order to contextualise real-world 3D positions and accurately locate and identify neural tract pathways in the brain. Utilising anonymised tract data and advanced neuroimaging technologies pioneered by Trinity College Institute of Neuroscience (TCIN), the Technological University Dublin (TU Dublin) School of Media created an interactive visualisation environment using the Unity 3D game engine. This virtual reality visualisation utilises the Oculus Rift Virtual Reality (VR) peripheral to realise the first ever virtual dissection of the fornix in-vivo in a highly interactive full 3D environment. Ethical approval was granted by St James/Tallaght Research & Ethics Committee. MRI tract coordinate data in the form of .wrl format 3D objects were converted to game-engine ready formats such as .obj through a 3D editing program (3DS Max) then imported into Unity. A virtual representation of a human brain was created, and scale, position, and rotation manipulation of the VR environment implemented, using natural motion tracking and minimal button usage. Isolation of individual or groups of neural tracts was achieved using hand tracking and spatial selection. Positional data was mapped to MRI image planes in order to overlay traditional MRI images at each position to aid diagnostic accuracy. In summary, virtual dissection of the fornix pathway in the human brain, first individuated by TCIN was transcribed into a 3D VR gaming environment for spatially intuitive visualisation, manipulation, and analysis