Correction for T1 Effect Incorporating Flip Angle Estimated by Kalman Filter in Cardiac-Gated FMRI

Jaemin Shin¹, Xiaoping Hu¹

To overcome cardiac pulsation related artifact, cardiac-gated acquisition has been utilized with correction for T1 effect due to variation of the cardiac cycle but it is only valid for the flip angle of 90. B1 inhomogeneity can often cause a significant variation in flip angle, e.g., 65 to 105 over the brain volume for a nominal flip angle of 90 at 3 T. In this work, we developed a generalized correction technique for T1 effect incorporating actual flip angle, estimated from fMRI dataset itself using Unscented Kalman filter. The new technique is demonstrated with simulated data and in vivo data.