Soft elastic hydrogel couplants for ultrasonography

Area of Science:

• Biomedical Engineering
• Materials Science
• Medical Imaging

Background:

• Effective ultrasound imaging relies on couplants for conformal contact between the probe and skin.
• Existing couplants (liquid and solid gels) have limitations: liquid gels deform skin, affecting elastography, while solid gels lack conformal contact, especially on curved surfaces.
• Skin deformation and nonconformal contact are critical issues in ultrasonography, particularly for high-curvature body parts like tumors, fingers, and elbows.

Purpose of the Study:

• To develop an improved couplant for ultrasonography that overcomes the limitations of existing materials.
• To enhance ultrasound imaging quality and accuracy, particularly in challenging anatomical regions.
• To provide a couplant that maintains conformal contact without deforming the skin surface.

Main Methods:

• A novel bilayer hydrogel pad design was engineered, comprising a stiff layer and a compliant layer.
• The design aimed to provide mechanical support, allow smooth probe movement, and conform to irregular skin surfaces.
• Clinical experiments were conducted using the bilayer hydrogel pad for ultrasound imaging of various anatomical sites.

Main Results:

• The bilayer hydrogel pad effectively bears external compression, facilitating smooth probe manipulation.
• It achieves conformal contact with high-curvature body parts, such as thyroid nodules, skin tumors on elbows, and fingers.
• The couplant prevents significant skin deformation, crucial for accurate tissue modulus estimation in elastography.
• High-quality ultrasound imaging was achieved in clinical trials using the developed bilayer hydrogel pad.

Conclusions:

• The bilayer hydrogel pad represents a significant advancement in ultrasound couplant technology.
• Its unique design addresses critical challenges in maintaining conformal contact and preventing skin deformation.
• This innovative couplant shows promise for a wide range of diagnostic applications in ultrasonography.