Plaque localization enhanced by exogenous chromophore β-carotene

β-carotene, an antioxidant which may alter the course of atherosclerosis by preventing the oxidation of LDL, has potential therapeutic benefit in humans. Studies are outlined which illustrate that yellow β-carotene is only present in atherosclerotic plaque but not in the normal artery. By absorbing 450-500 nm laser radiation, β-carotene confers preferential absorption to the plaque, making both selective ablation therapy and selective fluorescence detection possible. Furthermore, yellow coloration of plaques can also improve plaque visualization by angioscopy. Recently pathological studies suggest that vulnerable plaques may have thin fibrous caps overlying cholesterol-rich lipid cores. Therefore, yellow color variation in plaque visualization by angioscopy may be related to the cap thickness which is potentially important for predicting plaque disruption and thrombus formation