title: In vivo 31P spectroscopy by fully adiabatic extended image selected in vivo spectroscopy: a comparison between 3 T and 7 T.
abstract: An improved image selected in vivo spectroscopy (ISIS) sequence for localized (31)P magnetic resonance spectroscopy at 7 T was developed. To reduce errors in localization accuracy, adiabatic excitation, gradient offset independent adiabatic inversion pulses, and a special extended ISIS ordering scheme were used. The localization accuracy of extended ISIS was investigated in phantoms. The possible spectral quality and reproducibility in vivo was explored in a volunteer (brain, muscle, and liver). A comparison between 3 T and 7 T was performed in five volunteers. Adiabatic extended ISIS provided high spectral quality and accurate localization. The contamination in phantom experiments was only ∼5%, even if a pulse repetition time ∼ 1.2·T(1) was chosen to maximize the signal-to-noise ratio per unit time. High reproducibility was found in the calf muscle for 2.5 cm isotropic voxels at 7 T. When compared with 3 T, localized (31)P magnetic resonance spectroscopy in the human calf muscle at 7 T provided ∼3.2 times higher signal-to-noise ratio (as judged from phosphocreatine peak amplitude in frequency domain after matched filtering). At 7 T, extended ISIS allowed the performance of high-quality localized (31)P magnetic resonance spectroscopy in a short measurement time (∼3 to 4 min) and isotropic voxel sizes of ∼2.5 to 3 cm. With such short measurement times, localized (31)P magnetic resonance spectroscopy has the potential to be applied not only for clinical research but also for routine clinical practice.
authors: Department of Radiology, MR Center of Excellence, Medical University Vienna, Vienna, Austria.
authors: W
authors: W
authors: Bogner
authors: M
authors: M
authors: Chmelik
authors: O C
authors: OC
authors: Andronesi
authors: A G
authors: AG
authors: Sorensen
authors: S
authors: S
authors: Trattnig
authors: S
authors: S
authors: Gruber
mesh_terms: D006801:Humans; D007866:Leg; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D018482:Muscle, Skeletal / Q000378:metabolism*; D019047:Phantoms, Imaging; D010725:Phosphocreatine / Q000378:metabolism; D010758:Phosphorus; D015203:Reproducibility of Results
chemical_list: D010725:Phosphocreatine; D010758:Phosphorus