Experimental 3-D Ultrasound Imaging with 2-D Sparse Arrays using Focused and Diverging Waves

Area of Science:

• Medical Imaging
• Ultrasound Technology
• Array Probe Development

Background:

• Three dimensional ultrasound (3-D US) imaging is advancing, but controlling large numbers of probe elements is a challenge.
• Two dimensional (2-D) sparse arrays offer a potential solution to reduce element count in 3-D US.
• Limited experimental validation exists for 2-D sparse array performance in 3-D US.

Purpose of the Study:

• To experimentally compare the performance of a fully wired 3-D US array with 2-D sparse arrays.
• To evaluate 2-D sparse array performance in both focused and compounded diverging wave (DW) transmission modes.
• To assess the impact of sparse array design on image resolution and contrast.

Main Methods:

• Experimental comparison of a 1024-element full array against a 256-element random and an optimized 2-D sparse array.
• Testing in both 3-D focused transmission mode and 3-D diverging wave (DW) transmission mode.
• Evaluation of image resolution and contrast metrics for each array configuration and transmission mode.

Main Results:

• The optimized 2-D sparse array achieved resolution and contrast comparable to the full array using only 25% of elements in focused mode.
• For the first time, 3-D DW mode was experimentally compared to 3-D focused mode.
• 3-D DW mode demonstrated superior contrast and resolution compared to 3-D focused mode, achieving volume rates up to 90/second (36x speed-up).

Conclusions:

• Optimized 2-D sparse arrays are a viable and efficient alternative for 3-D US imaging, significantly reducing element requirements.
• The 3-D diverging wave (DW) transmission mode offers substantial improvements in imaging speed, resolution, and contrast over traditional focused modes.
• These advancements pave the way for faster and higher-quality 3-D ultrasound examinations.