Sina Straub1, Mark E. Ladd1,2, Paul Chang3, and Sahar Nassirpour3
1Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, Faculty of Medicine, University of Heidelberg, Heidelberg, Germany, 3MR Shim GmbH, Reutlingen, Germany
1Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany, 2Faculty of Physics and Astronomy, Faculty of Medicine, University of Heidelberg, Heidelberg, Germany, 3MR Shim GmbH, Reutlingen, Germany
In this study, it was shown that some of
the most severe artifacts regularly observed in QSM can be mitigated with
improved local B0 shimming using a local array of shim coils.
Figure 2: Representative
Sagittal/ axial slices of susceptibility maps (QSM) and B0 maps are
shown for each volunteer with scanner only shim and with local shimming. Arrows
indicate inhomogeneities and artifacts. For better visualization, in each case
a zoomed-in window is also shown (dotted green rectangle) with higher contrast
Figure 1: The sagittal slices of the first echo magnitude
image of the field mapping sequence for each of the three measured subjects
are shown on top. In a-c histograms of the B0 maps for each volunteer measured
using the scanner-only shim (red) as well as the local shimming method (blue)
are shown.