Cem Murat Deniz1, 2, Ryan Brown1, Riccardo Lattanzi1, 2, Leeor Alon1, 2, Daniel K. Sodickson1, 2, Yudong Zhu1, 2
1Department of Radiology, Bernard and Irene Schwartz Center for Biomedical Imaging, New York University School of Medicine, New York, NY, United States; 2Sackler Institute of Graduate Biomedical Sciences, New York University School of Medicine, New York, NY, United States
Radiofrequency shimming with multiple channel excitation has been proposed to increase the transverse magnetic field uniformity and reduce specific absorption rate at high magnetic field strengths (≥ 7 Tesla), where wavelength effects can make traditional single channel volume coils unsuitable for transmission. In the case of deep anatomic regions and power-demanding pulse sequences, optimization of transmit efficiency may be a more critical requirement than homogeneity. This work introduces a new method to maximize transmit efficiency using multiple channel excitation and radiofrequency shimming. Shimming weights are calculated in order to obtain the highest possible transverse magnetic field using the lowest possible net radiofrequency power deposition into the subject.