High-frame-rate echocardiography using diverging transmit beams and parallel receive beamforming

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Cardiovascular Diagnostics

Background:

• Echocardiography is crucial for diagnosing heart conditions, assessing global function via B-mode and M-mode.
• Advanced methods like myocardial strain and strain rate estimation evaluate regional heart function.
• High frame rates are essential for analyzing dynamic myocardial events like contraction, relaxation, and vibration propagation.

Purpose of the Study:

• To develop a novel method for high-frame-rate (over 300 Hz) echocardiography.
• To enable detailed evaluation of myocardial function and viscoelasticity through advanced imaging techniques.

Main Methods:

• Implemented parallel receive beamforming with reduced transmits (15) and 16 receiving beams per transmission.
• Utilized transmit compounding to ensure uniform sensitivity across scan lines.
• Investigated both plane waves and diverging waves, with diverging waves showing superior performance due to beam width characteristics.

Main Results:

• Spatial resolution was validated using nylon wires, achieving point spread functions comparable to conventional methods with diverging waves and compounding.
• A significant increase in lateral sidelobe levels was observed with parallel beamforming.
• Successfully measured the heart of a healthy male subject at a frame rate of 316 Hz.

Conclusions:

• Achieved a frame rate of 316 Hz, a substantial improvement over conventional echocardiography (tens of Hz).
• Maintained a full lateral field of view of 90°.
• Image contrast was slightly degraded due to increased sidelobe levels, but the high frame rate facilitates advanced cardiac function analysis.