Phosphorus-31 magnetic resonance spectroscopy of the human liver

During the last decade, progresses in the field of nuclear magnetic resonance spectroscopy (MRS), have allowed metabolic studies of complex biological systems. Since the coming out of whole body magnets, clinical applications are possible; they utilize magnetic field gradients coupled with selective pulse sequences. The main nuclei which can be observed in vivo are the proton, the phosphorus-31 (³¹P) and the carbon-13 (¹³C). In the present work, we have studied the human liver in vivo by ³¹P MRS. The study has needed the building of radiofrequency coils (surface coils), specially designed for liver observation (16 cm diameter ³¹P coil and 19 cm diameter proton coil, both transmitter and receiver coils). Measurements have been carried out by using the chemical shift imaging (CSI) technique. We have obtained localized ³¹P NMR spectra corresponding to different voxels within the hepatic tissue. The conditions of spectra acquisition and the saturation effect on phosphorylated metabolite signals — in particular phosphodiester signals — are discussed