Graeme F. Mason

Biological and clinical MRS at ultra-high field

The advantages of performing spectroscopic studies at higher field strengths include increased SNR, improved spectral resolution for J‐coupled resonances, and improvements in the selectivity of spectral editing schemes. By using pulse sequences that minimize the required echo time, refocus J‐evolution, employ low peak B1 requiring pulses and take advantage of spectroscopic imaging methods, these advantages can also be utilized in clinical applications of spectroscopy at high field. In addition to the static measurements measurements of N‐acetyl aspartate (NAA), creatine (CR) and choline (CH) which can be performed at 1.5 T, high resolution measurements of glutamate, glutamine, GABA and the incorporation of 13C labeled glucose into glutamate are possible with improved spatial and spectral resolution. These methods have been utilized in patients with seizure disorders and multiple sclerosis to identify, characterize and map the metabolic changes associated with these diseases and their treatment.

The 13C isotope and nuclear magnetic resonance: unique tools for the study of brain metabolism.

As studies of brain metabolism grow in complexity, investigators turn increasingly to nuclear magnetic resonance spectroscopy combined with13C isotopic labeling. The unique ability to detect labeling non-destructively in specific carbon positions of individual compounds has opened the way to investigate brain metabolism in systems ranging from cellular preparations to the human brainin vivo. This review is written for investigators whose backgrounds do not include detailed knowledge of principles of nuclear magnetic resonance. Its purpose is to show the wide array of NMR techniques for13C detection that are available for application in different systems to study aspects of brain metabolism, such as metabolic compartmentation and measurements of the tricarboxylic acid cycle ratein vivo. Basic NMR concepts are explained, and, because each detection method possesses specific advantages to address the requirements of different experimental goals, basic explanations and examples are given for each technique. The review should provide readers with a basic understanding of the methods of13C detection by NMR and assess which of the methods are most applicable to the particular issues they may face in their own research.