Sodium Ions (Na+) play an important role in many cellular physiological processes. In healthy tissue, the extracellular concentration of Na+ is approximately ten-fold higher than the intracellular concentration. A breakdown of this concentration gradient or an increase of the intracellular sodium content can be used as an early marker in many disease processes. In this presentation the focus will be on brain-related applications of sodium MRI. In addition, the required hardware, as well as image acquisition and post-processing techniques that are suitable for sodium MRI will be discussed.