Presenter: Russell H. Behler
Advisor(s): Caterina M. Gallippi
Author(s): Russell H. Behler1, Douglas M. Dumont2, Timothy C. Nichols3, Thomas H. Fischer3, Elizabeth P. Merricks3 and Caterina M. Gallippi1
Graduate Program: (1) Biomedical Engineering, (2) Duke Univeristy Department of Biomedical Engineering, (3) University of North Carolina Department of Pathology

Title: Acoustic Radiation Force Impulse Imaging, Molecular Ultrasound and Their Ability to Enhance Cardiovascular Disease Diagnosis

Abstract: Cardiovascular disease (CVD) is the leading killer of Americans, and earlier disease detection could significantly improve outcomes. Current diagnostic imaging techniques are effective for identifying morphological or functional changes associated with atherosclerosis. However, these techniques are not capable of characterizing early disease stages. A novel imaging technology, Acoustic Radiation Force Impulse (ARFI) ultrasound, is well positioned to enhance CVD diagnostics by differentiating tissue structure via mechanical properties. Additionally, while conventional ultrasound contrast agents are useful for blood signal enhancement, they lack the ability to assist in the diagnosis of localized endothelial inflammation associated with atherosclerosis. We are developing novel inflammation targeted ultrasound contrast agents to seek out such areas of inflammation and enhance detection of the earliest stages of atherogenesis. Using a relevant pig model of CVD, two-dimensional ARFI imaging ex vivo suggested a stiff arterial wall region beneath a stiff focal plaque with a fibrous cap, also implying that the region of the plaque had reduced elasticity compared to non-atherosclerotic vessel wall. These results correlated with immunohistochemistry. In vivo, ARFI imaging identified stiff, diffuse atherosclerosis as well as a soft focal plaque protruding into the lumen, which was not readily evident on B-Mode ultrasound. The results support ARFI for enhanced CVD diagnosis in humans. In addition to ARFI, preliminary studies have demonstrated molecular ultrasoundís potential diagnostic relevance. Novel acoustic probes, formulated from bioengineered rehydrated lyophilized platelets, have been shown to be echogenic in pilot experiments. Given that these probes are formulations of native platelet cells, we hypothesize that they will exhibit a natural affinity to sites of inflammation. We also hypothesize that while both of these methods have shown initial success, future development of the two methods in conjunction will lead to further enhanced diagnosis, and earlier, more appropriate treatment.