Intravascular Photoacoustic and Autofluorescence Imaging for Detecting Intraplaque Hemorrhage: A Feasibility Study

Intraplaque hemorrhage (IPH), which is a trigger and conveys all blood components into the plaque, influencing the cholesterol crystal formation and retention, haemoglobin and oxidative enzymes, and blood-borne proteolytic activity. IPH is one of the key determinants for plaque vulnerability. In this paper, we proposed a dual-modality endoscope probe with a diameter of 1 mm for simultaneously detecting the lipid core and IPH, our system was composed of photoacoustic imaging (PAI) and near-infrared auto-fluorescence imaging (NIRAFI). The lipid as endogenous marker of intravascular PAI could visualize the lipid distribution of atherosclerotic plaque, and bilirubin as the marker of intravascular NIRAFI was used to locate and quantify the IPH. The phantom and ex vivo rabbit aorta experiments had proved the feasibility and capability of the dual-mode probe for imaging IPH and lipid core expansion. And the results indicated that the dual-mode intravascular endoscope had the potential for accurately detecting IPH in atherosclerotic plaques.