Phase rotation methods in filtering correlation coefficients for ultrasound speckle tracking

Area of Science:

• Medical Imaging
• Biomedical Engineering
• Cardiovascular Research

Background:

• Speckle-tracking myocardial strain imaging is crucial for assessing cardiac function.
• Peak hopping artifacts in strain analysis can lead to inaccurate results, especially with high strains.
• Existing correlation coefficient filters require high computational power and interpolation for large strains.

Purpose of the Study:

• To develop a computationally efficient method for reducing peak hopping artifacts in speckle-tracking strain imaging.
• To enhance the accuracy of myocardial strain analysis, particularly in cases of large systolic strains.
• To improve displacement estimation in cardiac imaging.

Main Methods:

• A narrow band approximation using phase rotation was developed to facilitate correlation coefficient filtering.
• Correlation coefficients were phase rotated to increase coherence before filtering.
• Rotated phase angles were determined by local strain and spatial position.

Main Results:

• The proposed phase rotation method effectively enhances true correlation coefficient peaks in large strain applications.
• The technique minimizes peak hopping artifacts without significant loss of coherence.
• The method reduces the computational burden associated with traditional correlation coefficient filtering.

Conclusions:

• Phase rotation-based correlation coefficient filtering offers an efficient solution for peak hopping artifacts in myocardial strain imaging.
• This approach improves the accuracy of displacement estimation, especially in challenging large strain scenarios.
• Combining this filtering with Viterbi-based estimators promises further advancements in cardiac motion analysis.