Factors Affecting Accuracy of T1 Estimates in Vivo by Variable Flip Angle Approach for DGEMRIC

Angela Manuel¹, Wei Li¹, Vladimir Jellus², Timothy Hughes², Pottumarthi V. Prasad¹

Previous experience with phantoms has shown good agreement in T1s obtained by standard 2D IR-TSE and 3D VFA techniques. However, the level of agreement in vivo was less. In order to determine the reason behind this inaccuracy, we investigated a number of potential factors, such as number of flip angles used, fitting routines, and effects of B1 inhomogeneity. Our results suggest that increasing the number of flip angles had minimal or no effect on improving the agreement between the techniques and that B1 inhomogeneity may be most responsible for the apparent poor agreement between 3D VFA and 2D IR-TSE estimates.