In vivo 3P spectra were acquired from the human primary visual cortex at 7 T. The relaxation times of the cerebral metabolites, intracellular pH, rate constant (kf) of the creatine kinase (CK) reaction, and nuclear Overhauser enhancement (NOE) on the detected phosphorus moieties from irradiation of the water spins were measured from normal subjects. With a 5-cm-diameter surface coil, 3D 31P chemical shift imaging was performed with a spatial resolution of 7.5 ml and an acquisition resolution of 8 min, resulting in a signal-to-noise ratio (SNR) for phosphocreatine (PCr) resonance of 32. The apparent T1 and T2 of PCr measured at 7 T were 3.37 ± 0.29 s and 132.0 ± 12.8 ms, respectively, which were considerably longer than those of adenosine triphosphate (ATP) (T1: 1.02-1.27 s; T2: 25-26 ms). The NOE measured in this study was 24.3% ± 1.6% for PCr, and 10% for ATP. The kf measured in the human primary visual cortex was 0.24 ± 0.03 s-1. The results from this study suggest that ultra-high-field strength is advantageous for performing in vivo 31P magnetic resonance spectroscopy (MRS) in the human brain.
- High field
- Human brain
- Magnetic resonance spectroscopy
- P MRS