Simultaneous EPI-Based T1, T1, and T2' Mapping

Daniel L. Shefchik¹, Andrew S. Nencka¹, Andrzej Jesmanowicz¹, James S. Hyde¹

The accelerated gradient-recalled echo, asymmetric spin-echo pulse sequence was developed to produce relaxivity maps with the same EPI readouts used in functional studies. The sequence had the ability to calculate T1, T2 and T2* voxel-wise relaxivity maps from a single excitation utilizing echo pairs. These echo pair calculations led to systematic errors due to low SNR for T2 and T2* echo pairs and the inaccuracy of the flip angles. A new non-linear model was developed which greatly increase the accuracy of the EPI collected relaxivity maps, while maintaining the ability to provide precise dynamic time series T2 and T2* maps.