Nuclear-Overhauser-enhanced MR imaging of (31)P-containing metabolites: multipoint-Dixon vs. frequency-selective excitation.
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.
['Rink|Kristian|K|', 'Berger|Moritz C|MC|', 'Korzowski|Andreas|A|', 'Breithaupt|Mathies|M|', 'Biller|Armin|A|', 'Bachert|Peter|P|', 'Nagel|Armin M|AM|']
D000328:Adult D000465:Algorithms D006801:Humans D007089:Image Enhancement D007090:Image Interpretation, Computer-Assisted D021621:Imaging, Three-Dimensional D007866:Leg D008279:Magnetic Resonance Imaging D008297:Male D018482:Muscle, Skeletal D010759:Phosphorus Isotopes D012016:Reference Values D055815:Young Adult
(31)P MRI Dixon High-energy phosphate metabolism Nuclear Overhauser effect Steady-state free precession (SSFP)