CENTRAL NERVOUS SYSTEM: STATE OF THE ART S205 Understanding Diffu- sion MR Imaging Tech- niques: From Scalar Diffusion-weighted Imaging to Diffusion Tensor Imaging and

The complex structural organization of the white matter of the brain can be depicted in vivo in great detail with advanced diffusion mag-netic resonance (MR) imaging schemes. Diffusion MR imaging tech-niques are increasingly varied, from the simplest and most commonly used technique—the mapping of apparent diffusion coefficient val-ues—to the more complex, such as diffusion tensor imaging, q-ball imaging, diffusion spectrum imaging, and tractography. The type of structural information obtained differs according to the technique used. To fully understand how diffusion MR imaging works, it is help-ful to be familiar with the physical principles of water diffusion in the brain and the conceptual basis of each imaging technique. Knowledge of the technique-specific requirements with regard to hardware and acquisition time, as well as the advantages, limitations, and potential interpretation pitfalls of each technique, is especially useful