[Hydrogen spectroscopy in neurology]

for a long time to the research field despite its unquestionable diagnostic value. The availavility of programs able to automatically obtain a spectrum, and the current possibility of estimating easily the relationship among its different peaks, have approached this diagnostic technology to the current clinical situation. With hydrogen MRI spectroscopy (MRS) it is possible to obtain additional information which make it possible to distinguish among different neurological alterations with similar morphological appearance, such as cerebral tumors and pseudotumoral types of inflammatory processes, or tumor recurrence and radionecrosis. On other occasions, it makes it possible to detect alterations which are invisible by imaging study, such as medial temporal sclerosis, or multiple sclerosis. It is also very useful in following-up many alterations, either in their natural history, as in Alzheimers disease, or in order to monitor treatments on cerebral tumors or infectious processes. However, MRS does not often show pathognomonic patterns, so it is always recommended to consider it not just in the clinical context, but as inseparable part of an MR study, either structural or functional (diffusion, perfusion), since it is this is how it provides more useful information from a clinical point of view.