Zhipeng Cao1, Adrian Paez2, Chunming Gu2, and Jun Hua2
1Vanderbilt University, Nashville, TN, United States, 2Johns Hopkins University, Baltimore, MD, United States
1Vanderbilt University, Nashville, TN, United States, 2Johns Hopkins University, Baltimore, MD, United States
A novel magnitude-least-squares algorithm is developed for robust patient-tailored 2D
multislice imaging at UHF with RF shimming and
small-tip-angle multi-spoke pulse design. The algorithm is effective against excitation nulls and sub-optimal pulse solutions for brain and knee imaging.
Fig 4. Designed flip angle
distribution (top row) and acquired EPI images (bottom row) from one
representative slice in the human brain at 7T with system default quadrature
mode, dynamic multislice RF shimming with conventional MLS, and with proposed FD-MLS.
The RF pulse design ROI is labeled in red. With fixed system gain, the FD-MLS
improved the signal homogeneity and SNR over default quadrature, while not
forming the null as the conventional MLS.
Fig 5. Evaluation of FD-MLS with knee data from an 8Tx array with two different postures. The FD-MLS not only improved over null solutions (in slices marked by the green stars), but also improved over local minimum solutions (marked by green circles).