Sodium MRI is an increasingly applied non-invasive imaging technique with a fast growing body of evidence regarding its diagnostic value, especially in neuroradiology. This lecture will discuss principle applications of Sodium-MRI at clinical and ultra-high magnetic fields (3T and 7T) providing a window into tissue metabolism and pathophysiological alteration of sodium concentrations associated with various neurological diseases. This will include applications for initial diagnosis and disease characterization (e.g. neuro-oncology, epilepsy, neurodegeneration, and neuroinflammation), prognostication, and therapy response monitoring. Difficulties regarding a broader clinical translation of sodium MRI will be discussed.