基于贝塞尔光束的大深度范围高分辨血管内光声成像方法的研究

The rupture of vulnerable plaque is the main cause of acute coronary disease. Neovascularization is an important fator to decide the vulnerability of atherosclerotic plaques. Due to the spread distribution of neovascularization within a large depth and its limited size of tens of microns, it is necessary to image the neovascularization with high resolution with extended imaging depth to realize the accurate diagnosis, which is beyond the reach of current intravascular imaging techniques. .Intravascular photoacoustic imaging holds the properties of high optical contrast、ultrasonic resolution of depth and spectral resolution, which has been successfully applied in intravascular lipid and inflammation imaging, but still not realize the neovascularization imaging. .This proposal will combine Bessel beam with large focal depth and intravascular photoacoustic imaging systems to realize high-resolution imaging with extended imaging depth. What we will do in this proposal includes: (1) realizing the high-resolution photoacoustic imaging with extended imaging depth with novel fiber-AXIGRIN (based on Bessel beam excitation); (2) Developing novel methods to remove the influence of the Bessel beam concentric rings to the photoacoustic imaging; (3) Based on the two works above, researching the multi-modality photoacoustic imaging of neovascularization and inflammation. This proposal is expected to boost the intravascular photoacoustic imaging and clinical diagnosis of vulnerable plaques.

易损斑块的破裂是造成急性心血管事件的主要原因。滋养微血管对斑块易损性具有重大影响。但由于滋养微血管的深度分布范围大，且大部分直径仅有数十微米，因此对其精准探测需要较大深度、高分辨率的成像。但现有血管内成像技术很难同时满足这一对矛盾需求。.血管内光声成像技术兼具光学对比度、超声深度分辨能力和基于光谱的成分分辨能力，已成功应用于血管内斑块脂质和活动炎症的精准成像，但尚未解决滋养微血管成像问题。.本项目拟将具有超长聚焦区的贝塞尔光束引入光声系统，实现大深度高分辨的血管内光声成像。本项目拟研究：（1）基于贝塞尔光束的新型血管内光声成像方法，利用光纤-自聚焦锥镜实现微小空间内的高分辨率大深度光声成像；（2）适用于光声的贝塞尔旁瓣光束的消除方法，实现高信噪比成像；（3）以前述方法为基础，研究同时获取滋养微血管和炎症活动的多模态功能成像方法。本项目有望推动光声技术的发展和对斑块的临床检测研究。

采用血管内光声成像的方法对冠脉动脉粥样硬化斑块的炎症、新生血管等组分进行识别和量化，是实现斑块易损性精准诊断的重要方法。但现有的血管内光声成像系统基于高斯光束激发，难以实现大深度范围内的高分辨成像，只能在特定深度上实现斑块炎症、新生血管等的高分辨成像。为此，本项目开发了自聚焦透镜和锥镜组合的光学系统，在微小空间内实现了长焦区贝塞尔光束的产生，其中心光斑的尺寸在5微米以内，贝塞尔区的长度大于1.5 cm，理论上可以实现1.5 cm深度范围内的高分辨光声成像。同时本项目还采用光声成像的方法对斑块炎症成分进行了识别和量化，开发了高速的血管内光声成像系统，以期应用于炎症、新生血管等信息的获取。相关研究成果已发表了2篇SCI文章，2篇EI论文，3项发明专利。本项目所取得的研究成果为斑块的多维信息获取、精准诊断提供新的思路，有利于血管内光声成像技术的进一步诊断应用。