An optimisation-based iterative approach for speckle tracking echocardiography

Figures

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  Fig. 1. Speckle tracking using BM where a region in the image (kernel) is selected and sought for in the next image by sequentially trying out different positions, testing the similarity between the kernel and the pattern observed in that position. The position where the similarity between the kernel and the observed pattern is maximal is accepted as the new position of the original kernel

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  Fig. 2. Flowchart showing the steps involved in solving the proposed optimisation-based tracking algorithm

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  Fig. 3. An example A4C from the Siemens healthy sequence and corresponding displacement vector fields during the rapid ejection phase (peak systole). a Zoomed view of LV cropped from the original image. b Ground-truth. c–d Displacement fields obtained from standard BM and optimised BM approach in the rapid ejection phase, respectively. Corresponding figures for other vendors are provided in Appendix A

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  Fig. 4. Boxplots of the error for the healthy sequence from Siemens. The error is computed as the magnitude of the difference between the calculated and ground-truth displacement vectors and is provided for standard (left) and proposed (right) tracking methods. The x-axis shows the frame number

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  Fig. 5. Displacement error for the healthy A4C synthetic sequences across all vendors for the two speckle tracking approaches. The horizontal line represents mean; the box signifies the quartiles, and the whiskers represent the 2.5% and 97.5% percentiles

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  Fig. 6. Top: an A4C view with the LV myocardium segmentation regions overlaid. Below: violin plots of the error in the segmental strain measurements for the healthy synthetic sequence from Siemens. The solid black line represents mean, and the green line represents the median; the box signifies the quartiles, and the whiskers represent the 2.5% and 97.5% percentiles

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  Fig. 7. Comparison of GLS measurements obtained from the standard BM approach for the healthy and ischaemic LCX (ischaemic left circumflex coronary artery) cases across all vendors with the known ground-truth. The solid and dashed blue lines represent the calculated strain values for healthy and ischaemic cases, respectively. The solid and dashed magenta lines indicate the corresponding ground-truth

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  Fig. 8. Same as Fig. 7, but for the optimised BM approach

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  Fig. 9. Example of a (presumably) “common sense” editing in a commercial package on one frame, where 3 regional strain values are given for the lateral wall, but there is no visible myocardium to be tracked in that region