Abstract
Diffusion tensor imaging is capable of resolving large fiber bundles (e.g. the corpus callosum) and has been quite informative in understanding the overall structural connectivity of the brain. Recent data has shown that traditional resolution limitations can be exceeded in humans in vivo to submillimeter resolution. This chapter discusses these new techniques, and specific applications to small pathways such as the perforant path in the medial temporal lobe. High-resolution diffusion tensor imaging is a promising new tool that can be used to discover novel biomarkers for Alzheimer's disease and other disorders. It allows for a much more detailed investigation of brain white matter than previously possible, perhaps offering clues into the first signs of synaptic deterioration that may precede frank neuron loss. Although these methods are still in their infancy and many challenges have to be overcome before they can be used in a clinical fashion, results so far have been promising. Challenges and future directions are discussed in detail.