Hybrid Ultrasound Transducers

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Abstract Deep vein thrombosis (DVT)/Pulmonary Embolism (PE) affects as many as 900,000 people a year. One third of people will have a reoccurrence within 10 years according to the CDC. The main methods of breaking up blood clots or “clot busting” are through pharmacological dissolution, which has limited success and involves substantial bleeding risk, or mechanical fragmentation or removal using transcutaneous or intravascular device. Ultrasound thrombolysis can be classed by the delivery method. Catheter-delivered external transducer ultrasound thrombolysis (CDEUST), involves guide wire is used to deliver safe and efficient treatment. However this approach is limited by considerable dissipation of ultrasound energy due to unwanted rotation and flexion of the wave guide about the central axis. Transcutaneous-delivered external ultrasound thrombolysis (TDEUST) high intensity and long duration of exposure could cause thermal damage to soft tissue. Intravascular ultrasound thrombolysis (IVUST) is known with higher efficiency to target, however, this method is currently used in combination with pharmacological method, to increase efficiency. The challenges of IVUST include the generation of a high amplitude-peak negative in a miniaturized transducers and the spatial limitation for the low-frequency ( Researchers at NC State have designed catheter-mounted, small aperture, hybrid ultrasound transducer and arrays for intravascular thrombolysis. The catheter diameter is 1 mm and external diameter of the transducer assembly is 2 mm. Two designs have been developed for front-firing and side- firing active material, a piezoelectric IVUS transducer and a hybrid IVUS transducer Both designs have a small aperture, low frequency operation, capability of microbubble injection, high pressure generation, to induce cavitation. The piezoelectric transducer contains both front and side firing active materials, generating 1-2 MHz ultrasound waves. The hybrid IVUS combines a piezoelectric transmitter with a laser-generated focused ultrasound lens for front-firing, the sharing focal point with the front piezoelectric element can efficiently induce cavitation. These customized transducers enable safe, simple and efficient thrombolysis. It realizes mechanical busting without tissue damage and the minimized need for pharmacological assistance. Advantages No tissue or skin damage Higher lytic rate than current IVUS thrombolysis techniques Radial and lateral mode Catheter mounted Small aperture Low frequency operation 1-2 MHz front firing element 1-2.5 MHz side firing element Technology #15222 Categories Imaging Ultrasound Medical Device Minimally Invasive