Affiliations: [a] Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland | [b] Departments of Radiology, Universities of Lausanne and Geneva, Lausanne, Switzerland
Correspondence:
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Correspondence to: Cristina Cudalbu, PhD, Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory for Functional and Metabolic Imaging (LIFMET), Station 6, CH F1 602 (Bâtiment CH), CH-1015 Lausanne, Switzerland. Tel.: +41 21 693 0580; Fax: +41 21 693 7960; E-mail: [email protected].
Abstract: In vivo localized proton magnetic resonance spectroscopy (1H MRS) became a powerful and unique technique to non-invasively investigate brain metabolism of rodents and humans. The main goal of 1H MRS is the reliable quantification of concentrations of metabolites (neurochemical profile) in a well-defined region of the brain. The availability of very high magnetic field strengths combined with the possibility of acquiring spectra at very short echo time have dramatically increased the number of constituents of the neurochemical profile. The quantification of spectra measured at short echo times is complicated by the presence of macromolecule signals of particular importance at high magnetic fields. An error in the macromolecule estimation can lead to substantial errors in the obtained neurochemical profile. The purpose of the present review is to overview methods of high field 1H MRS with a focus on the metabolite quantification, in particular in handling signals of macromolecules. Three main approaches of handling signals of macromolecules are described, namely mathematical estimation of macromolecules, measurement of macromolecules in vivo, and direct acquisition of the in vivo spectrum without the contribution of macromolecules.
Keywords: In vivo short echo time 1H MRS, macromolecule contribution, quantification of neurochemical profile
