Table 1.

Sensitivity results for Heart 1. The sensitivity study results for the Heart 1 analyses indicate that warping was relatively insensitive to image noise, moderate decreases in image intensity, and changes in fiber orientation. An SNR level of 1 (bold) caused severe degradation of the registration results with large increases in %RMSE and a reduction of the R ² values. The lack of active contraction in the analysis also resulted in degradation of the error measures.

	Cir. strain		Radial strain
	%RMSE	R 2	%RMSE	R 2
Validation study	0.098	0.813	0.138	0.780
SNR 8	0.109	0.813	0.122	0.780
SNR 4	0.109	0.811	0.133	0.798
SNR 1	0.236	0.220	0.196	0.210
SNR 0.5	0.280	0.770	0.439	0.790
SNR 0.1	0.131	0.786	0.145	0.750
Reduction in fiber angle (+5%)	0.105	0.813	0.143	0.796
Increase in fiber angle (−5%)	0.116	0.810	0.122	0.800
10% reduction in intensity	0.117	0.820	0.116	0.780
20% reduction in intensity	0.116	0.810	0.139	0.800
40% reduction in intensity	0.129	0.783	0.139	0.790
No active contraction	0.181	0.770	0.191	0.750