Figure 1.
Prospective real-time motion correction for MRS. Left panel: External (optical camera) and internal (navigator) tracking systems. Note that NMR probes use a combination of external and internal tracking. Middle Panel: Localization update is possible with both external and internal tracking, however, B0 shimming is possible only with navigators with B0 field mapping. Right panel: Examples of MR spectra under stationary conditions and in the presence of motion with no correction (NoCo), motion correction only (MoCo), and with both motion and shim correction (ShMoCo). Decreased SNR and line broadening/splitting are noticed in NoCo spectra. MoCo recovers partially the SNR and linewidth, while the full spectral quality is restored only if both motion and shim corrections (ShMoCo) are performed.