Abstract #2904

Accounting for B1 Void using Optimized Transmit Pulses in Ultra-High Field MRI

Ling Xia¹, Tingting Shao¹, Minhua Zhu¹, Guofa Shou¹, Feng Liu², Stuart Crozier²

¹Department of Biomedical Engineering, Zhejiang University, Hangzhou, China, People's Republic of; ²School of Information Technology & Electrical Engineering, University of Queensland, Brisbane, Australia

This work presents a novel approach to account for the limited coverage of RF energy in ultra high field MRI. Based on the recently developed parallel transmission technology, an optimized 3D tailored RF (TRF) pulse has been proposed to upgrade the RF excitation. The pulse is designed with an adaptive stack-spiral trajectory that is tailored according to the high-weight k-space area, which is most responsible for the desired excitation pattern. An iterative RF pulse design method is employed to ensure the excitation accuracy. Test simulations show that the proposed scheme optimally upgrades the excitation over the whole imaging area which includes deep domain where RF energy can be difficult to penetrate at ultra high field.