Wang Bo, Su Jimmy, Amirian James, Litovsky Silvio H, Smalling Richard, Emelianov Stanislav
Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78712, USA.
Annu Int Conf IEEE Eng Med Biol Soc. 2009;2009:4767-70. doi: 10.1109/IEMBS.2009.5334213.
Large lipid core is common in rupture-prone atherosclerotic plaques. Detection of the location and distribution of lipid in the atherosclerotic plaques can greatly benefit the diagnosis and treatment of vulnerable plaques. Recently introduced intravascular photoacoustic (IVPA) imaging - a technique to image the optical absorption property of tissue - can be used to detect and differentiate atherosclerotic plaques. In this work, we further investigated the ability of using spectroscopic IVPA imaging to visualize the lipid in atherosclerotic plaques. IVPA imaging was performed on an ex-vivo rabbit aorta in the 1200 - 1230 nm wavelength range. In the lipid-rich plaques, the photoacoustic signal strength within this spectral range behaved similar to the optical absorption spectrum of fatty tissue. To distinguish lipid from other types of tissue, correlation analysis was used. Specifically, intraclass correlation between the IVPA signals and the absorption spectrum of lipid reconstructed from multi-wavelength IVPA images was conducted on a pixel-by-pixel basis. The resulted correlation map showed the distribution of lipid in the atherosclerotic plaques. The distribution of lipid is further confirmed by histopathological analysis of tissue. The results of our study suggest that spectroscopic IVPA imaging, together with correlation analysis, may be used to detect lipid in atherosclerotic plaques.
大脂质核心在易破裂的动脉粥样硬化斑块中很常见。检测动脉粥样硬化斑块中脂质的位置和分布对易损斑块的诊断和治疗大有裨益。最近引入的血管内光声（IVPA）成像——一种对组织光学吸收特性进行成像的技术——可用于检测和区分动脉粥样硬化斑块。在这项工作中，我们进一步研究了使用光谱IVPA成像可视化动脉粥样硬化斑块中脂质的能力。在1200 - 1230nm波长范围内对离体兔主动脉进行IVPA成像。在富含脂质的斑块中，该光谱范围内的光声信号强度表现类似于脂肪组织的光学吸收光谱。为了将脂质与其他类型的组织区分开来，使用了相关性分析。具体而言，在逐像素的基础上对IVPA信号与从多波长IVPA图像重建的脂质吸收光谱之间进行组内相关性分析。所得的相关性图谱显示了动脉粥样硬化斑块中脂质的分布。通过组织的组织病理学分析进一步证实了脂质的分布。我们的研究结果表明，光谱IVPA成像与相关性分析相结合，可用于检测动脉粥样硬化斑块中的脂质。
