Cardiac spectroscopy

energy status of the myocardium. MR Spectroscopy (MRS) explores the chemical shift dimension of the MR signal. MR visible nuclei like 1H–and 31P exhibit slightly shifted resonance frequencies depending on the molecular environment. Thus, compounds can be identified from spectra of these chemical shifts. 31P–MRS was the first method used to investigate cellular metabolism in–vivo, using a simple surface coil. This method was soon adapted for the heart and then used in humans. By observing high-energy phosphate metabolites with 31P-MRS in patients with cardiomyopathies a link was shown between heart failure and changes in the levels of phosphocreatine. Creatine compounds can also be observed with more technically accessible 1H–MRS techniques. With 1H–MRS it is also possible to quantify intra-myocellular triglyceride content. These triglycerides are a major fuel for the heart and abnormal levels are linked to obesity and heart failure. A comprehensive but simple description is given on how to acquire and process in-vivo cardiac MRS data in humans. This chapter will focus on 1H-MRS because this is by far the most accessible technique.