Metabolic Imaging in Humans

Taylor L. Fuss, Leo L. Cheng
2016 Topics in Magnetic Resonance Imaging (TMRI)  
Metabolic imaging enhances understanding of disease metabolisms and holds great potential as a measurement tool for evaluating disease prognosis and treatment effectiveness. Advancement of techniques, such as magnetic resonance spectroscopy (MRS), positron emission tomography (PET), and mass spectrometry (MS), allow for improved accuracy for quantification of metabolites and present unique possibilities for use in clinic. This article reviews and discusses literature reports of metabolic
more » ... in humans published since 2010 according to disease type, including cancer, degenerative disorders, psychiatric disorders, and others, as well as the current application of the various related techniques. Keywords metabolic imaging; magnetic resonance spectroscopy imaging (MRSI); humans Metabolites are the small molecule intermediates and products associated with metabolic pathways. Physiological and pathological processes in an organism, such as diseases, activate or deactivate these pathways and result in changes of metabolite concentrations. At present, metabolic imaging uses techniques including magnetic resonance spectroscopy (MRS), positron emission tomography (PET), and mass spectrometry (MS) imaging to visualize and quantify metabolites, and provide a unique perspective to assist disease diagnosis, evaluate patient prognostication, and monitor treatment effectiveness. MRS is a radiation free technique that can be used in tandem with MR imaging (MRI) to noninvasively characterize tissue with signals from hydrogen protons ( 1 H) and other nuclei, such as carbon-13. PET detects pairs of gamma rays emitted by an injected positronemitting radiotracer that is retained at disease foci through characteristic pathological processes. Depending on the radiotracer injected, different metabolic pathways can be observed and probed. MS imaging (MSI), a newly developed imaging modality, follows the traditional MS concept of ionizing chemicals with electrons and sorting them by mass-tocharge (m/z) ratio to identify the presence of molecules, but accomplishes these processes on the surfaces of tissue, rather than in the traditional gas or liquid phases. While still in its † Abbreviations 2HG 2-hydroxyglutarate 3D three-dimensional AD Alzheimer's disease ALS amyotrophic lateral sclerosis aMCI amnestic mild cognitive impairment ANOVA analysis of variance aPS atypical parkinsonian syndrome (aPS) BOLD-fMRIblood oxygenation level-dependent functional MRI Cho choline Cit citrate Fuss and Cheng
doi:10.1097/rmr.0000000000000100 pmid:27748708 pmcid:PMC5117434 fatcat:tqhp5dmct5fsdkxmd4ygnxuc24