Time Efficient Flip Angle Measurement at 7T
Xu D, Vigneron D, Chen A, Cunningham C, Pauly J, Nayak K, Kelley D
UCSF, UCSF/UC Berkeley
With the non-significant risk classification of 7T, high field MR imaging is poised to advance clinical radiology. Unlike 1.5T and 3T, 7T systems do not have a body coil, so excitations are performed by smaller volume or surface coils, yielding highly variable excitation. In this abstract, we utilized a fast double angle B1 mapping sequence to obtain the flip angle. In vivo B1 maps demonstrated as large as 3-fold differences in some regions in effective flip angle experienced by tissue in slice and across slices. They also highlight the differences between excitation offered by coils with different designs.