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Abstract #0607

Adiabatic Pulse Design for Bloch-Siegert B1+ Mapping

Mohammad Mehdi Khalighi1, Brian K. Rutt2, Adam B. Kerr3

1Global Applied Science Lab, GE Healthcare, Menlo Park, CA, United States; 2Radiology Deaprtment, Stanford University, Stanford, CA, United States; 3Electrical Engineering Department, Stanford University, Stanford, CA, United States

B1+ mapping by the Bloch-Siegert (B-S) method has been shown to be fast and accurate; however, it suffers from high SAR and long TE. We have developed a new adiabatic B-S RF pulse design method, which achieves more B-S B1+ measurement sensitivity for a given pulse width, SAR and T2* than previous B-S pulse designs. A 2ms adiabatic B-S pulse generates 2.5 times more angle to noise ratio maps in the brain compared to 6ms conventional Fermi pulse with the same SAR. The adiabatic B-S pulse performance was validated both in phantoms and in vivo.