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Abstract #2513

Practical SAR Constraints of the Bloch-Siegert B1 Mapping Method at 3T

Daniel J. Park1, Ahsan Javed1, Neal K. Bangerter1, 2, Joshua Kaggie3, Glen R. Morrell2

1Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT, United States; 2Department of Radiology, University of Utah, Salt Lake City, UT, United States; 3Department of Physics, University of Utah, Salt Lake City, UT, United States

The recently-introduced Bloch-Siegert shift (BSS) method of B1 mapping has several advantages over existing B1 mapping methods. However, a major limitation of the BSS method is the high specific absorption rate (SAR) caused by the BSS pulse. The BSS pulse generates phase which is proportional to B12, and the accuracy of the method increases with increasing amplitude of the BSS pulse. Since SAR of this pulse is proportional to B12, SAR constraints place limits on the performance of the BSS method. This study investigates the tradeoff between SAR limits and BSS pulse area.