Optically Validated Microvascular Phantom for Super-Resolution Ultrasound Imaging.

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Ultrasound Technology

Background:

• Super-resolution ultrasound (SRUS) visualizes microvasculature beyond the diffraction limit by tracking microbubble (MB) contrast agents.
• Existing SRUS phantoms are fragile, lack physiological relevance, and offer limited validation capabilities.
• Development of robust, durable phantoms is crucial for advancing SRUS technology and algorithm evaluation.

Purpose of the Study:

• To propose and demonstrate a method for fabricating durable microvascular phantoms for SRUS.
• To enable optical gauging for accurate SRUS validation.
• To create phantoms with physiologically relevant microvasculature for repeatable SRUS testing.

Main Methods:

• Fabrication of microvascular phantoms using a microvasculature negative print embedded in Polydimethylsiloxane (PDMS).
• Creation of branching microvascular structures with variable density and optically validated diameters down to 20 micrometers.
• Validation of SRUS imaging against optical measurements.

Main Results:

• Achieved optically validated vessel diameters down to 20 micrometers.
• Demonstrated an average SRUS error of 35 micrometers, decreasing to 15 micrometers with over 1000 localized MBs.
• Confirmed long-term durability with <10% variance in properties and maintained mechanical toughness after one year.

Conclusions:

• A method for fabricating durable, optically validated microvascular phantoms for SRUS has been presented.
• These phantoms allow for precise quantification of SRUS performance.
• The developed phantoms will facilitate further development and application of SRUS technology.