Depth-of-field enhancement in Filtered-Delay Multiply and Sum beamformed images using Synthetic Aperture Focusing

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Signal Processing

Background:

• Synthetic Aperture Focusing (SAF) enhances ultrasound image quality uniformly across depth.
• Non-linear beamforming algorithms like Filtered-Delay Multiply and Sum (F-DMAS) improve image contrast.
• Classical dynamic focusing in ultrasound imaging has limitations in depth and brightness.

Purpose of the Study:

• To combine the Synthetic Transmit Aperture (STA) technique with the Filtered-Delay Multiply and Sum (F-DMAS) beamforming algorithm.
• To evaluate the impact of STA on F-DMAS beamforming for ultrasound imaging.
• To investigate the performance of SAF/STA with F-DMAS, considering signal-to-noise ratio.

Main Methods:

• Implementation of Synthetic Transmit Aperture (STA) where single elements transmit and all elements receive.
• Application of Filtered-Delay Multiply and Sum (F-DMAS) beamforming, based on backscattered signal spatial correlation.
• Analysis of image contrast, brightness, depth of field, and signal-to-noise ratio.

Main Results:

• F-DMAS with receive-only dynamic focusing yields high contrast but brightness loss at depth.
• Combining F-DMAS with STA compensates for brightness loss and improves depth of field.
• Reduced signal-to-noise ratio in SAF/STA affects F-DMAS image characteristics.

Conclusions:

• The combination of STA and F-DMAS offers superior ultrasound image quality and depth of field compared to classical methods.
• This approach addresses limitations of receive-only dynamic focusing, providing more uniform image brightness.
• Further investigation into monostatic SAF with F-DMAS is warranted to assess its potential.