Solid Hydrogel Couplants for Skin Superficial Blood Flow Imaging With Super-Resolution Ultrasound

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Materials Science

Background:

• Ultrasound transducer pressure compromises superficial blood flow imaging accuracy.
• Near-field acoustic interference further degrades image quality.
• High-resolution imaging of skin microvasculature remains a challenge.

Purpose of the Study:

• Introduce a novel solid hydrogel coupling medium for enhanced superficial blood flow ultrasound imaging.
• Overcome limitations of probe pressure and acoustic interference.
• Improve accuracy and resolution of skin microvascular visualization.

Main Methods:

• Fabricated a sodium alginate and acrylamide (SA-PAM) solid hydrogel coupling pad.
• Performed mechanical characterization via tensile testing.
• Evaluated imaging performance using ultrasound localization microscopy (ULM) on rat skin under varying pressures with microbubble contrast agents.

Main Results:

• The SA-PAM hydrogel demonstrated superior acoustic coupling and reduced near-field interference.
• Significantly enhanced visualization of dermal and subcutaneous microvascular structures compared to liquid agents, even under pressure.
• 3D super-resolution ultrasound imaging revealed improved microvascular flow continuity and vessel density.

Conclusions:

• The SA-PAM hydrogel coupling pad provides a novel solution for high-resolution ultrasound imaging of superficial skin blood flow.
• Reduces image distortion caused by probe pressure, offering improved vascular imaging.
• Shows potential for early detection of microvascular lesions in diabetes and monitoring inflammatory skin diseases.