Ultrasonic properties of bio-compatible silicone rubbers for matching transit-time piezoelectric transducers for blood flow estimation in coronary vessels

The properties of different bio-compatible silicone rubbers (BSRs) are studied with the purpose to determine the best material to fabricate the coupling pad between the piezomaterials and the vessels in an ultrasonic transit time probe to measure the blood flow in coronary vessels. The objective is to reduce the energy loss due to reflection at the interfaces and due to attenuation in the coupling material. In addition, we also seek to eliminate unwanted shear waves. Different BSRs samples are fabricated and studied using two different ultrasonic techniques: air-coupled and water immersion. In addition, the possibility to introduce some material modifications is also discussed.