Assessing the viscoelastic properties of thrombus using a solid-sphere-based instantaneous force approach.

Area of Science:

• Biomedical Engineering
• Biophysics
• Materials Science

Background:

• Thrombus viscoelasticity is crucial for hemostasis, but traditional rheometry can disrupt clot structure.
• A non-destructive method is needed to accurately assess clot mechanical properties.

Purpose of the Study:

• To evaluate a novel acoustic method for measuring blood clot viscoelasticity.
• To compare acoustic measurements with traditional rheometry.

Main Methods:

• An acoustic method was developed using focused transducers to track sphere displacement within a blood clot.
• The system was calibrated with gelatin phantoms and then applied to porcine blood clots with varying hematocrits.
• Sphere motion induced by an acoustic force determined the clot's viscoelastic modulus.

Main Results:

• The acoustic method successfully measured the viscoelastic modulus of blood clots.
• Shear modulus increased with lower hematocrit (173 Pa for 40% Hct to 619.5 Pa for plasma).
• Viscosity decreased with lower hematocrit (0.32 Pa·s for 40% Hct to 0.16 Pa·s for plasma).

Conclusions:

• The novel acoustic method is a feasible alternative to rheometry for assessing blood clot viscoelasticity.
• Red blood cell concentration and fibrinogen levels are key determinants of clot mechanical properties.