Photoacoustic cardiovascular imaging: A new technique for imaging of atherosclerosis and vulnerable plaque detection

The sudden rupture of an atherosclerotic plaque is one of the main causes of stroke and stroke induced death. Plaque composition plays a critical role in plaque rupture. In order to differentiate between different plaque components, an imaging technique suitable for patient follow-up is needed. Photoacoustic (PA) imaging (PAI), a relatively new imaging technique, can also be used for cardiovascular imaging as it resolves optical contrast with ultrasonic resolution, visualizes oxygenated and deoxygenated haemoglobin and a large range of optical agents. PAI can be used to visualize molecular tissue changes, not only stenosis, and relates to the evaluation treatment protocols and/or post-procedural follow-up. In this review, we explain the principles of PAI, describe the recent developments in PAI systems used for non-invasive carotid imaging and intravascular imaging of coronary atherosclerosis and suggest areas of future research that will help bring PAI imaging towards clinical cardiovascular imaging.