基于多阶微分的相敏光学相干弹性成像

Phase-resolved optical coherence elastography based on multi-differential operation

为了提高光学相干弹性成像(OCE)灵敏度,达到通过测量微小形变实现生物组织弹性成像的目的,提出了一种基于多阶微分放大的相敏OCE方法。本方法采用压电陶瓷(PZT)作为外部驱动激励源,以PZT谐振频率为驱动频率,通过提取相邻时刻微小位移改变引起的相位差,并对其作微分放大从而实现微小位移提取。通过对有内嵌物的琼脂模拟样品进行弹性成像,可将反射系数相近、弹性模量相差较大的不同样品进行区分。仿体实验说明,本文方法具有较高的高灵敏性,可用于实现弹性成像。通过获得离体大鼠肺部肿瘤组织的三维弹性图像和二维切面图像,实现了肿瘤的弹性成像。癌症组织实验结果表明,本方法在微小肿瘤病灶边缘诊断方面具有较高的实用价值,通过弹性图像中可以清晰地辨别出微小肿瘤组织及周围正常组织。

In order to improve the sensitivity of optical coherence elastography, we propose a multi-order phase differential method, which can be used to reconstruct elastic images of biological tissue by measur- ing micro-displacement. In this method, a piezoelectric transducer with the driven frequency of resonant frequency is used as the external mechanical excitation source. The micro-displacement can be extracted by obtaining the changes of phase between the adjacent time points and performing multi-differential op- eration on the extracted phase. The first experiment is made on a phantom including an inclusion. The in- clusion in the phantom can be identified from the surroundings clearly. The result verifies the feasibility of our method and its high sensitivity. The second experiment is made on a lung tissue with tumor of a mouse in vitro. 2D and 3D optical coherence elastography images are obtained to achieve the elastic ima- ging of the tumor. It is easy to find the tumor location in the organization. The experimental results of tumor tissue show that this method has high practical value in the diagnosis of micro tumor edge,and it can clearly identify the micro tumor tissue and surrounding normal tissue through the elastic images.