Experimental evaluation of blocking effect on emboli in the aorta ascendens by using phased array ultrasound

Emboli generated in cardiac surgery can result in many postoperative neurological complications. There are many methods to reduce the amount of emboli or to block them. Nevertheless, many of methods have limitation. In this study, ultrasonic radiation force generated by phased array ultrasound is used to block emboli and the blocking effect is evaluated. We do vivo experiment on eight pigs (40kg). After opening thorax, we put ultrasound transducer between ascending aorta and brachiocephalic artery. The man-made emboli are injected in the left auricle 8 times on each pig, 4 times with ultrasound transducers off and 4 times with ultrasound transducers on. When emboli flow to ascending aorta, ultrasonic radiation force will act on emboli and block some of them from flowing into brachiocephalic artery. And emboli flowing into the right common carotid artery would be detected by PHILIPS CX50. At the end of the experiment, the sonicated tissue is cut for histopathology test. The results of vivo experiment demonstrate the feasibility and effect of blocking in the evaluation.