Quantitative Photoacoustic Imaging Biomarkers for Characterization of Thrombosis

PROJECT SUMMARY Thrombosis is the major underlying pathology that causes many cardiovascular diseases including stroke, ischemic heart disease, and venous thromboembolism (VTE). VTE, which includes both deep vein throm- bosis (DVT) and pulmonary embolism, is the third most common cause of death in the world, to coronary

heart disease and ischemic stroke and is responsible for more than 500,000 deaths in the US each year. Imaging methods to diagnose VTE include compression ultrasonography, computed tomography pulmonary angiography (CTPA), or ventilation-perfusion lung scanning. However, each of these imaging methods are qualitative and do not offer a method to determine the type or age of the thrombus, only

visualize its presence or absence. Treatment for these conditions varies depending on the thrombus type; therefore, the development of non-invasive diagnostic tools to characterize clot microstructure is critical to the selection of proper treatment and clinical pathways. Photoacoustic imaging, which relies on the acoustic response from tissue after the absorption of pulsed

light, is a promising method to both visualize and characterize thrombi. The photoacoustic signal depends on the optical absorption properties of the imaged tissue which vary across wavelengths of light, but exist- ing methods rely on either a single optical wavelength or on differences between the clot and surrounding

blood and do not attempt to fully characterize the clot or understand the underlying microstructure. We hypothesize that there is rich acoustic and optical information present within blood clots that can be ex- tracted and quantified using photoacoustic imaging. Therefore, driven by a team of primarily undergrad-

uate researchers, we will characterize the unique optical properties of biological chromophores relevant in thrombus formation (Aim 1) and develop algorithms to quantitatively measure blood clot composition in photoacoustic imaging (Aim 2). These studies will establish a foundation for quantitative photoacoustic characterization of thrombosis

and develop quantitative monitoring tools to non-invasively diagnose and track thrombus composition over time. With these tools, we envision improved, targeted therapies resulting in faster treatment and improved patient outcomes. Furthermore, this project will have a significant impact on the undergraduate research

landscape at Oakland University, supporting the involvement of at least five undergraduate researchers over the project’s duration.