title: Use of phased array coils for a determination of absolute metabolite concentrations.
abstract: This work describes the use of phased array coils for a quantification of absolute metabolite concentrations. The method is demonstrated for single-voxel localized proton MRS of human brain with an eight-element receive-only head coil. It is based on the transmitter reference amplitude of the body coil used for RF transmission. A relative sensitivity of every element of the phased array coil is derived from a combination of two reference scans without water suppression that correspond to either the body coil in transmit-receive mode or the phased array coil in conjunction with body coil excitation. Experimental results were obtained at 2.9 T for both phantoms and 12 human subjects in different locations of gray and white matter. The data demonstrate that the procedure is technically robust and without a penalty in measuring time. Moreover, it takes full advantage of the signal-to-noise gain for quantitative proton MRS and may be extended to other phased array coils without the need for a recalibration.
authors.affiliation: Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für biophysikalische Chemie, 37070 Göttingen, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Natt
authors.forename: Vitaliy
authors.initials: V
authors.lastname: Bezkorovaynyy
authors.forename: Thomas
authors.initials: T
authors.lastname: Michaelis
authors.forename: Jens
authors.initials: J
authors.lastname: Frahm
mesh_terms: D000328:Adult; D001921:Brain / Q000378:metabolism*; D001923:Brain Chemistry; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation / Q000379:methods*; D008297:Male; D019047:Phantoms, Imaging