Transcutaneous Imaging of Rabbit Kidney Using 3-D Acoustic Wave Sparsely Activated Localization Microscopy With a...

Area of Science:

• Biomedical imaging
• Ultrasound technology
• Microvascular research

Background:

• Super-resolution ultrasound (SRUS) imaging, or ultrasound localization microscopy (ULM), provides sub-diffraction resolution of micro-vessels by tracking microbubbles.
• Previous 3-D selective SRUS methods using matrix arrays and phase change contrast agents (PCCAs) were limited by small fields of view (FOV) and complex hardware.

Purpose of the Study:

• To develop and validate a novel 3-D acoustic wave sparsely activated localization microscopy (AWSALM) technique.
• To overcome the limitations of previous SRUS methods by increasing FOV and reducing hardware complexity.

Main Methods:

• Proposed 3-D AWSALM utilizing PCCAs and a 128+128 row-column-addressed (RCA) array for ultrafast acquisition.
• Validated the method on an in-vitro microflow phantom and subsequently in a rabbit kidney in-vivo.

Main Results:

• 3-D AWSALM generated images of a phantom with 8x resolution improvement over the system's point spread function in under 5 seconds.
• Achieved 3-D microvascular structure, flow speed, and direction super-resolution mapping of a rabbit kidney in under 15 seconds.
• Demonstrated selective visualization of microvasculature within specific activation volumes and downstream vessels.

Conclusions:

• Successfully demonstrated large FOV 3-D AWSALM using an RCA probe.
• 3-D AWSALM provides a unique in-vivo imaging tool for fast, selective, and large FOV vascular flow mapping.