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A quality-guided displacement tracking algorithm for ultrasonic elasticity imaging.

Chen L, Treece GM, Lindop JE, Gee AH, Prager RW - Med Image Anal (2008)

Bottom Line: This increases the accuracy and reduces the computational expense compared with exhaustive search.This paper introduces a novel displacement tracking algorithm, with a search strategy guided by a data quality indicator.Comparisons with existing methods show that the proposed algorithm is more robust when the displacement distribution is challenging.

View Article: PubMed Central - PubMed

Affiliation: Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK. lc420@eng.cam.ac.uk

ABSTRACT
Displacement estimation is a key step in the evaluation of tissue elasticity by quasistatic strain imaging. An efficient approach may incorporate a tracking strategy whereby each estimate is initially obtained from its neighbours' displacements and then refined through a localized search. This increases the accuracy and reduces the computational expense compared with exhaustive search. However, simple tracking strategies fail when the target displacement map exhibits complex structure. For example, there may be discontinuities and regions of indeterminate displacement caused by decorrelation between the pre- and post-deformation radio frequency (RF) echo signals. This paper introduces a novel displacement tracking algorithm, with a search strategy guided by a data quality indicator. Comparisons with existing methods show that the proposed algorithm is more robust when the displacement distribution is challenging.

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Related in: MedlinePlus

Flowchart of the single-seed quality-guided tracking algorithm.
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fig2: Flowchart of the single-seed quality-guided tracking algorithm.

Mentions: This strategy ensures that high quality regions are processed first, while low quality regions are avoided at an early stage – see Fig. 1. Accurate displacement estimates in high quality regions are propagated to other points, while the inevitably poor estimates in lower quality regions are prevented from spreading. Note, however, that there is no guarantee that points are processed in order of quality: a high quality point will not be processed until the tracking path reaches it. Nevertheless, since there is no constraint on the direction of propagation, the algorithm is able to process a region with an arbitrary geometrical shape. Fig. 2 shows a flowchart for the single-seed, quality-guided tracking strategy with the correlation quality indicator.


A quality-guided displacement tracking algorithm for ultrasonic elasticity imaging.

Chen L, Treece GM, Lindop JE, Gee AH, Prager RW - Med Image Anal (2008)

Flowchart of the single-seed quality-guided tracking algorithm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2665204&req=5

fig2: Flowchart of the single-seed quality-guided tracking algorithm.
Mentions: This strategy ensures that high quality regions are processed first, while low quality regions are avoided at an early stage – see Fig. 1. Accurate displacement estimates in high quality regions are propagated to other points, while the inevitably poor estimates in lower quality regions are prevented from spreading. Note, however, that there is no guarantee that points are processed in order of quality: a high quality point will not be processed until the tracking path reaches it. Nevertheless, since there is no constraint on the direction of propagation, the algorithm is able to process a region with an arbitrary geometrical shape. Fig. 2 shows a flowchart for the single-seed, quality-guided tracking strategy with the correlation quality indicator.

Bottom Line: This increases the accuracy and reduces the computational expense compared with exhaustive search.This paper introduces a novel displacement tracking algorithm, with a search strategy guided by a data quality indicator.Comparisons with existing methods show that the proposed algorithm is more robust when the displacement distribution is challenging.

View Article: PubMed Central - PubMed

Affiliation: Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, UK. lc420@eng.cam.ac.uk

ABSTRACT
Displacement estimation is a key step in the evaluation of tissue elasticity by quasistatic strain imaging. An efficient approach may incorporate a tracking strategy whereby each estimate is initially obtained from its neighbours' displacements and then refined through a localized search. This increases the accuracy and reduces the computational expense compared with exhaustive search. However, simple tracking strategies fail when the target displacement map exhibits complex structure. For example, there may be discontinuities and regions of indeterminate displacement caused by decorrelation between the pre- and post-deformation radio frequency (RF) echo signals. This paper introduces a novel displacement tracking algorithm, with a search strategy guided by a data quality indicator. Comparisons with existing methods show that the proposed algorithm is more robust when the displacement distribution is challenging.

Show MeSH
Related in: MedlinePlus