Carotid atherosclerosis detection using photoacoustic imaging system

Abstract

Carotid arteries are important channels delivering blood and oxygen to brain. Atherosclerosis plaque in carotid arteries hinders blood delivery, and plaque rupture causes stroke, leading to high morbidity and motility. Extensive preclinical and clinical studies showed that atherosclerosis inflammation activities are highly related to plaque vulnerability. Thus, visualizing the inflammation of atherosclerosis plaques is important in atherosclerosis vulnerability assessment. In this study, photoacoustic imaging modality was applied for carotid atherosclerosis inflammation identification of mouse in vivo. Deficient apolipoprotein E (ApoE-/-) mice with high-fat diet and normal diet for 16 weeks were employed as atherosclerosis models and control models, respectively. Photoacoustic molecular probes with optical absorption at nearinfrared wavelength and specifically target cluster of differentiation 36 (CD36) were employed to mark inflammation cells in carotid atherosclerosis plaques of mouse in vivo. Noninvasive imaging of atherosclerosis inflammation cells marked by molecular probes was performed by point-to-point scanning with a custom-built acoustic-resolution photoacoustic imaging system. Considering low scattering of near-infrared light in tissues and mature commercialization of laser, excitation wavelength in this research is chosen at 1064 nm. Carotid arteries with and without atherosclerosis plaques have been noninvasively imaged and distinguished. Furthermore, carotid atherosclerosis with different inflammation severity has been analyzed by photoacoustic imaging and immunohistochemistry staining. Photoacoustic signal from atherosclerosis arteries showed high relativity with inflammation severity defined by immunohistochemistry staining, evidencing the reliability of the novel imaging technology in atherosclerosis inflammation identification. This study paves the way for photoacoustic imaging technology to atherosclerosis inflammation identification, severity quantification and even further atherosclerosis therapy.