Improvement of T1 Accuracy with the Correction of Imperfect Excitation Flip Angle: Toward the Application of Arterial Spin Labeling
Zheng J, Zhang H, Wang J, Woodard P
Washington University School of Medicine
The aim of this study was to investigate B1 inhomogeneity effect on the accuracy of T1 calculated with a T1 regression algorithm adapted for inversion (IR) prepared single shot gradient echo (GRE) based arterial spin labeling sequence. In the simulation, we found that 90% efficiency of the nominal excitation flip angle (&[alpha]) resulted in 1.5% overestimation of the actual T1 (900 ms). To improve the accuracy of the measured T1 in a phantom, we corrected the measured excitation flip angle in the T1 fitting, which might increase the final accuracy of the calculated T1 (approximately 3~4% error of the true T1).