Diffusion Tensor MRI Visualization

Diffusion Tensor Magnetic Resonance Imaging (DT-MRI or DTI) is emerging as an important technology for elucidating the internal structure of the brain and for diagnosing conditions affecting the integrity of nervous tissue. DTI measurements of the brain exploit the fact that the network of fibers has a characteristic microstructure that constrains the diffusion of water molecules within it. The direction of fastest diffusion is aligned with fiber orientation in a pattern that can be numerically modeled by a diffusion tensor. DTI is the only modality for non-invasively measuring diffusion tensors in living tissue, making it especially useful for studying the directional qualities of brain tissue. Application areas include neurophysiology, neuroanatomy, and neurosurgery, as well as the diagnosis of edema (swelling), ischemia (brain damage from restricted blood flow), and certain types of brain tumors. One of the fundamental problems in understanding and working with diffusion tensor data is its threedimensional and multi-variate nature. Each sample point in a DTI scan can be represented by six inter-related values, and many features of interest are described in terms of derived scalar and vector fields, which are logically overlayed on the original tensor field. Thus, the central tasks of DTI visualization include: