The effect of respiratory motion on in vivo 31P magnetic resonance spectroscopic imaging in the human liver at 7 Tesla

Motivation: Prospective gating potentially reduces respiratory motion-induced degradation in 31P liver MRSI at the cost of increased acquisition time. This presents a difficult trade-off, since the protocols are already time-consuming while the effects of motion are yet unknown. Goal(s): To characterize spectral quality degrading effects of typical respiratory motion on human liver 31P MRSI data. Approach: We analyzed spectra obtained from free breathing human liver 31P MRSI scans to determine differences in spectral quality between uncorrected and prospectively gated acquisitions using a respiratory belt. Results: We found a significant difference in spectral line width between gated and non-gated acquisitions. Impact: Showing that respiratory motion induces significant degradation of the spectral quality in in vivo liver 31P MRSI acquisitions, this study justifies the application and further development of prospective gating, as well as other respiratory motion correction methods.