One of the significant obstacles of measuring mechanical properties of blood vessels is that vascular wall deformations under physiologic pressures only exhibit small deformations with the usual (physiologic) forces applied. By altering the forces across a vessel wall, the deformations induced from physiologic pressure across the arterial wall is altered. By measuring the deformations with altered transmural forces, new and detailed measurements can be made about the mechanical properties of the vessel. A non-invasive free-hand ultrasound scanning procedure was performed to apply external force, comparable to the force generated in measuring a subject’s blood pressure, to achieve higher strains by equalizing the internal arterial baseline pressure. When the applied pressure matched the internal baseline diastolic pressure, strain and strain rate increased by a factor of 10 over a cardiac cycle. The feasibility of this technique has been validated through ex- and in-vivo measurements.
US patent 7,318,804.