TABLE 2.

The effect of excitation flip angle α and the number of k-space lines per segment (Seg) on the accuracy of T₁ measurements with a segmented multi-shot FLASH sequence when using the proposed T₁ regression fit and the three-parameter fit. (a) For the simplified phantom experiments simulating the myocardium and blood, images were gated with a fixed delay, and the signal intensities of the T₁ sampling curve were fitted with an assumed β value of 1. (b) For the six phantoms with a similar T₁ but varied T₂ values, the data acquisition were gated with the actual respiratory and ECG signals of a rat, and images were analyzed by these two fitting procedures twice: first with an assumed perfect inversion of β=1 and then with the actual β measured from IR-SE. The T₁ errors shown in the table were the average error for the series of phantoms studied in each group, in comparison with the T₁ values obtained from IR-SE.

(a)
T1 Error (%)	Flip Angle α (Seg = 4)				Segmentation Number (α = 10°)
	4°	8°	10°	12°	1	2	3	4
Three-Parameter Fit with β =1	−1.04	−4.61	−5.29	−7.73	−3.01	−4.46	−6.32	−5.29
Proposed T1 Fit with β =1	2.22	0.20	0.50	−1.30	0.15	−1.11	0.56	0.50

(b)
T1 Error (%)	Flip Angle α (Seg = 4)				Number of Seg (α = 10°)
	4°	8°	10°	12°	1	2	3	4
Three-Parameter Fit with β =1	−4.83	−5.41	−6.72	−8.76	−2.82	−6.95	−6.86	−6.72
Three-Parameter Fit with β <1	−1.45	−2.05	−3.40	−5.52	−0.65	−3.65	−3.54	−3.40
Proposed T1 Fit with β =1	−3.13	−1.51	−2.77	−3.77	−0.80	−3.21	−3.10	−2.77
Proposed T1 Fit with β <1	−1.04	0.75	−0.42	−1.32	0.39	−0.97	−0.82	−0.42