Ex vivo Characterization of Atherosclerosis using Intravascular Photoacoustic Imaging

The imaging of plaque composition represents one of the important steps in the interventional management of atherosclerosis. Intravascular photoacoustic (IVPA) imaging has the potential to play a major role in the detection and differentiation of an atherosclerotic lesion. The difference in the optical properties of the arterial wall and plaque constituents could be utilized to obtain high resolution photoacoustic images. In this work, through ex vivo imaging studies using a rabbit model of atherosclerosis, we evaluate the ability of IVPA imaging to detect and characterize the plaque. Specifically, the difference in the magnitude of the photoacoustic signals from the free lipids, macrophage foam cells, blood and the rest of the arterial wall were helpful in providing the contrast and detecting the fibro-cellular inflammatory plaque. The constituents identified in the IVPA images were confirmed by the results from histology.