title: Nuclear-Overhauser-enhanced MR imaging of (31)P-containing metabolites: multipoint-Dixon vs. frequency-selective excitation.
abstract: The purpose of this study is to develop nuclear-Overhauser-enhanced (NOE) [(1)H]-(31)P magnetic resonance imaging (MRI) based on 3D fully-balanced steady-state free precession (fbSSFP). Therefore, two implementations of a 3D fbSSFP sequence are compared using frequency-selective excitation (FreqSel) and multipoint-Dixon (MP-Dixon). (31)P-containing model solutions and four healthy volunteers were examined at field strengths of B0=3T and 7T. Maps of the distribution of phosphocreatine (PCr), inorganic phosphate (Pi), and adenosine 5´-triphosphate (ATP) in the human calf were obtained with an isotropic resolution of 1.5cm (1.0cm) in an acquisition time of 5min (10min). NOE-pulses had the highest impact on the PCr acquisitions enhancing the signal up to (82 ± 13) % at 3T and up to (37 ± 9) % at 7T. An estimation of the level of PCr in muscle tissue from [(1)H]-(31)P MRI data yielded a mean value of (33 ± 8) mM. In conclusion, direct [(1)H]-(31)P imaging using FreqSel as well as MP-Dixon is possible in clinically feasible acquisition times. FreqSel should be preferred for measurements where only a single metabolite resonance is considered. MP-Dixon performs better in terms of SNR if a larger spectral width is of interest.
authors.affiliation: Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany. Electronic address: k.rink@dkfz.de.
authors.forename: Kristian
authors.initials: K
authors.lastname: Rink
authors.affiliation: Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Moritz C
authors.initials: MC
authors.lastname: Berger
authors.affiliation: Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Korzowski
authors.affiliation: Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Mathies
authors.initials: M
authors.lastname: Breithaupt
authors.affiliation: Department of Neuroradiology, University of Heidelberg, Heidelberg, Germany.
authors.forename: Armin
authors.initials: A
authors.lastname: Biller
authors.affiliation: Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Bachert
authors.affiliation: Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Armin M
authors.initials: AM
authors.lastname: Nagel
mesh_terms: D000328:Adult; D000465:Algorithms; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D007866:Leg / Q000033:anatomy & histology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology; D010759:Phosphorus Isotopes; D012016:Reference Values; D055815:Young Adult
chemical_list: D010759:Phosphorus Isotopes
keywords: (31)P MRI; Dixon; High-energy phosphate metabolism; Nuclear Overhauser effect; Steady-state free precession (SSFP)