Detection of lipid in atherosclerotic vessels using ultrasound-guided spectroscopic intravascular photoacoustic imaging

Bo Wang,Silvio H Litovsky,Jimmy L Su,Stanislav Emelianov,Richard Smalling,James Amirian

doi:10.1364/oe.18.004889

Abstract

Lipid is a common constituent in atherosclerotic plaques. The location and area of the lipid region is closely related to the progression of the disease. Intravascular photoacoustic (IVPA) imaging, a minimally invasive imaging modality, can spatially resolve the optical absorption property of arterial tissue. Based on the distinct optical absorption spectrum of fat in the near infrared wavelength range, spectroscopic IVPA imaging may distinguish lipid from other water-based tissue types in the atherosclerotic artery. In this study, a bench-top spectroscopic IVPA imaging system was used to ex-vivo image both atherosclerotic and normal rabbit aortas. By combing the spectroscopic IVPA image with the intravascular ultrasound (IVUS) image, lipid regions in the aorta were identified. The results demonstrated that IVUS-guided spectroscopic IVPA imaging is a promising tool to differentiate lipid in atherosclerosis.

Highlights

Cardiovascular disease (CVD) has been the number one killer in the United States for over a century
The majority of CVD events are caused by atherosclerosis which is characterized by plaques building up inside the arterial wall [1]
Similar scattered distribution of lipid is reflected in the spectroscopic Intravascular photoacoustic (IVPA) image (Fig. 6(a)). These results suggest that spectroscopic IVPA imaging may be used to identify the lipid-rich regions in atherosclerotic vessels

Summary

Introduction

Cardiovascular disease (CVD) has been the number one killer in the United States for over a century. The majority of CVD events are caused by atherosclerosis which is characterized by plaques building up inside the arterial wall [1]. It is important to identify the vulnerable plaques, i.e., plaques that may undergo fast progression and put the patent at high risk due to possible plaque rupture leading to heart attack or stroke. Lipid is an important constituent in atherosclerosis. After entering the activated endothelial layer, LDL particles are endocytosed by macrophages located in the arterial wall. These LDL loaded macrophages later contribute to the lipid-rich necrotic core in the classical rupture prone plaques [3]. It has been shown that periadventitial fat is related to vessel remodeling and inflammation in atherosclerosis [4]. Imaging lipid deposits in atherosclerotic vessels will benefit both diagnosis and understanding of the pathology of atherosclerosis

Methods

Results

Conclusion