Gillian G Haemer1,2,3, Manushka V Vaidya1,2,3, Daniel K Sodickson1,2,3, Graham C Wiggins1,2, and Riccardo Lattanzi1,2,3
1The Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University School of Medicine, New York, NY, United States, 2The Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY, United States, 3The Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, NY, United States
Appropriate
high-permittivity, low-conductivity materials placed between the RF coil and
the sample can provide performance improvement in both transmission and
reception. We employed a simulation framework based on dyadic Green’s functions
for multi-layered spherical geometries to analyze how HPMs affect the tradeoff
between excitation homogeneity and global Specific Absorption Rate (SAR) for RF
shimming at 7T using an L-curves analysis. Three target excitation profiles
were analyzed, with uniform amplitude and varied phase, to determine the
influence that target phase distribution has on the optimal relative
permittivity results.
