Plots showing the mean errors in flow at stress. Positive dilation is in the direction of the epicardium, negative towards the blood pool. (a) shows the errors induced when the endocardial contour is modified whilst holding the epicardial contour at its reference state. (b) shows the converse arrangement. Error bars show ± one standard deviation. The corresponding tables show the p-value and 95% confidence interval for the t-test (n = 10).