Navigated single-voxel proton spectroscopy of the human liver.

The addition of a navigator echo acquisition to a 1H spectroscopy sequence allows retrospective motion correction using acceptance criteria based on measured displacement of the diaphragm. This technique has been applied to the acquisition of short echo-time 1H spectroscopy of the liver in seven normal subjects. Navigation correction significantly improved overall spectral quality as measured by the phase variance, linewidth and suppression ratio of the water resonance. The hepatic choline resonance was consistently observed in all navigated spectra. Retrospective navigation makes close to optimal use of data acquisition time and, unlike external respiratory transducers, allows direct measurement of diaphragm displacement. The reconstruction of multiple voxel spectra from a single data set was also demonstrated.