Cardiac Strain Imaging With Coherent Compounding of Diverging Waves

Area of Science:

• Cardiovascular Imaging
• Medical Ultrasound Technology
• Biomedical Engineering

Background:

• Current high frame rate cardiac strain imaging methods face challenges with motion artifacts and limited lateral resolution.
• Coherent compounding enhances echocardiographic image quality at high frame rates but hasn't been applied to cardiac strain imaging.
• Myocardial velocity can affect coherent compounding due to inter-frame displacements.

Purpose of the Study:

• To assess the feasibility and performance of coherent compounding for cardiac strain imaging.
• To evaluate this technique under both low and high myocardial velocity conditions.
• To compare coherent compounding with single diverging wave and conventional focusing methods.

Main Methods:

• Modeled left-ventricular contraction in short-axis view using an annulus with radial thickening and circumferential rotation.
• Generated simulated radio-frequency channel data using a cardiac phased array.
• Employed three beamforming methods: single diverging wave, coherent compounding of diverging waves, and conventional focusing.
• Estimated and compared axial, lateral, and radial displacements and strains against true values.
• Conducted in vivo feasibility studies comparing coherent compounding with single diverging wave imaging.

Main Results:

• At low myocardial velocities, coherent compounding (9 waves) showed significantly lower relative errors in axial (16.3%), lateral (40.4%), and radial (18.9%) strain compared to single diverging wave imaging (19.9%, 80.3%, 30.6%).
• Coherent compounding results were closer to conventional focusing (16.7%, 43.7%, 16%) than single diverging wave imaging.
• In vivo imaging demonstrated superior quality for left-ventricular radial strains using coherent compounding versus single diverging wave imaging.

Conclusions:

• Coherent compounding of diverging waves is feasible for cardiac strain imaging.
• This method offers improved performance over single diverging wave imaging while maintaining high frame rates.
• Coherent compounding holds potential for enhancing the diagnosis of myocardial strain-based cardiac diseases.