Hadamard-encoded synthetic beamforming for high frame rate acoustoelectric current source imaging

Area of Science:

• Biophysics
• Medical Imaging
• Ultrasound Technology

Background:

• Acoustoelectric (AE) imaging offers high spatial and temporal resolution for visualizing current source density (CSD) in biological systems.
• Conventional AE imaging methods suffer from low signal-to-noise ratio (SNR) and frame rates due to limitations in focused-beam scanning.

Purpose of the Study:

• To introduce and validate Hadamard synthetic beamforming (HSB) for ultrafast AE imaging.
• To overcome the trade-offs between field of view (FOV) and frame rate in conventional AE imaging.

Main Methods:

• Implementation of HSB using 16 transmit events per frame for spatial encoding.
• Utilized a 1.5D transducer array at 0.6 MHz center frequency for imaging current sources in a bio-mimicking phantom.
• Real-time imaging at a frame rate of 500 Hz.

Main Results:

• HSB achieved reconstructions limited by transducer geometry, enabling high frame rates.
• Demonstrated an approximate 5 dB SNR improvement over conventional focused-beam scanning.
• HSB provided comparable spatial resolution with fewer artifacts and improved image quality for distributed sources.

Conclusions:

• HSB is a practical and robust solution for achieving ultrafast AE imaging.
• This method significantly enhances SNR and frame rates for bioelectric current imaging.
• HSB offers improved image quality for dynamic and distributed biological current sources.