Transmit B1 Field Inhomogeneity & T1 Estimation Errors in Breast DCE MRI at 3T

Kyunghyun Sung¹, Bruce L. Daniel¹, Brian A. Hargreaves¹

Variable flip angle spoiled gradient echo (SPGR) acquisitions, called DESPOT1, are a common choice to measure T1 since they can provide a fast 3D volumetric T1 mapping. DESPOT1, however, heavily depends on the set of flip angles used, and therefore is sensitive to any flip angle variation. Transmit B1 field (B1) inhomogeneity creates flip angle variation and the variation tends to be 30 - 50% across the breast at 3T. In this work, we include B1 mapping in our breast DCE imaging protocol, and compensate T1 maps by including B1 variation in the DESPOT1 calculation. We then compare T1 relaxation in fat (as a validation) with and without compensating B1 variation in a total of 25 patients at 3T.