Improved T1 Mapping with Iterative Actual Flip-Angle Imaging (IAFI) Technique

Yiqun Xue¹, Mark A. Rosen¹, Hee Kwon Song¹

Actual flip angle imaging (AFI) technique was recently developed to estimate the true flip angle and has been used in conjunction with the variable flip angle (VFA) technique for improved T1 measurement accuracy. One of the limitations of AFI, however, is that the method assumes that T1 is much greater than the repetition time TR. When this assumption is violated, large errors can result in both the flip angle and T1 estimation. We propose an novel iterative AFI method which yields accurate T1 values without requiring that TR << T1.