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Abstract
An ischemic stroke is a cerebrovascular disease and may be caused by the occlusion of blood vessels by blood clots and other fatty deposits. It may cause disability or even death, because the brain cannot get enough blood and oxygen due to the stoppage of blood supply. Currently, treatment of one hour of intravenous tissue plasminogen activator (tPA) in the first three hours after symptom onset for acute ischemic stroke is the only approved method by the Food and Drug Administration (FDA). However, the safety of this method is of concern because of potential hemorrhaging that may be induced by the tPA. Ultrasound in combination with microbubbles is a potential alternative treatment for ischemic stroke. Two engineering problems associated with the treatment of ultrasound and microbubbles are considered in this dissertation. One is associated with the interaction of ultrasound with skull bone, and the other is focused on the interaction of ultrasound with microbubbles. The influence of skull bone microstructure on ultrasound propagation is examined using the finite element method and theoretical predictions. Ultrasound and microbubble mediated thrombolysis mechanisms are studied as well.
