Tess E Wallace1,2, Tobias Kober3,4,5, Simon K Warfield1,2, and Onur Afacan1,2
1Computational Radiology Laboratory, Boston Children's Hospital, Boston, MA, United States, 2Radiology, Harvard Medical School, Boston, MA, United States, 3Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland, 4Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland, 5LTS5, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
1Computational Radiology Laboratory, Boston Children's Hospital, Boston, MA, United States, 2Radiology, Harvard Medical School, Boston, MA, United States, 3Advanced Clinical Imaging Technology, Siemens Healthcare, Lausanne, Switzerland, 4Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland, 5LTS5, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland
FIDnavs embedded in a 3D EPI sequence can rapidly and accurately estimate shot-to-shot B0 field changes up to second order, resulting in substantially improved image quality and tSNR in the presence of spatiotemporal B0 variations.
Figure 4. Axial slice through 3D EPI image in a volunteer acquired in the reference position (a), combined image from reference position and nose touching (b), and augmented reconstruction using ground-truth MGRE field maps (c) and FIDnav field estimates (d). Difference images relative to the reference image (e–g). FID-navigated augmented reconstruction successfully compensates for artifacts in the combined image with B0 variations.
Figure 2. Comparison of field difference maps (in Hz) measured from multi-gradient-echo (MGRE) data and FIDnavs for changing shim settings in the ADNI phantom. FID-navigated field estimates are in excellent agreement with ground-truth pixel-wise field maps.
