Determination of Fetal Left Ventricular Volume Based on Two-Dimensional Echocardiography

Figures

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  Figure 1. Geometric assumptions for LV in the area-length method. (a) The geometric assumption for biplane area-length method. (b) The geometric assumption for single plane area-length method. L is the long-axis, and D1 and D2 are the minor axes taken from 4-chamber view and 2-chamber view.

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  Figure 2. Single plane Simpson's method. (a) Yellow solid contour is the border of LV. Red lines are axes for different individual cylinders. (b) 3D LV model by Simpson's method.

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  Figure 3. LV volume reference calculated by the VOCAL II mode in 4D view.

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  Figure 4. The architecture of a classic BP neural network.

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  Figure 5. Distances for the BP neural network input. O is the center of LV. pi (i = 1, 2,…, 16) are the selected points on the border of LV with the equal angle. di (i = 1, 2,…, 16) are the corresponding distances between pi and O.

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  Figure 6. The structure of the BP neural network. di (i = 1, 2,…, 16) are the distances, and V is the volume of LV.

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  Figure 7. CCC and ICC between volume references and BP neural networks with different hidden layers.

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  Figure 8. Bland-Altman plots of agreement between (a) the volume references and the area-length method, (b) the volume references and Simpson's method, (c) the volume references and the multivariate nonlinear regression equation method, and (d) the volume references and the BP neural network in volumes.

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  Figure 9. The variations of LV volumes for a case. The gold standard is the volume references.

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  Figure 10. Bland-Altman plots of agreement between the volume references and the BP neural network (a) for SV and (b) for EF.