阅读说明：本技术 一种提高导管偏振敏感光学相干层析成像解调效果的方法 (Method for improving demodulation effect of catheter polarization sensitive optical coherence tomography ) 是由 张俊杰 陈韵岱 田峰 陶魁园 陈芯 王皓 朱明� 于 2019-10-09 设计创作，主要内容包括：一种提高导管偏振敏感光学相干层析成像解调效果方法,其特征是在进行偏振解算之前选取导管护套外表面作为参考面,其不受待测样品影响；采用数据框选定导管护套外表面位置,每列A-line数据落在数据框中数幅强度最大的点为参考点。本发明能够提高偏振解算的速度。(A method for improving the demodulation effect of polarization-sensitive optical coherence tomography of a catheter is characterized in that the outer surface of a catheter sheath is selected as a reference surface before polarization calculation, and the reference surface is not influenced by a sample to be detected; and selecting the position of the outer surface of the catheter sheath by adopting a data frame, wherein the point with the maximum amplitude intensity in each column of A-line data falling in the data frame is taken as a reference point. The invention can improve the polarization resolving speed.)

1. A method for improving the demodulation effect of polarization-sensitive optical coherence tomography of a catheter is characterized in that the outer surface of a catheter sheath is selected as a reference surface before polarization calculation, and the reference surface is not influenced by a sample to be detected; and selecting the position of the outer surface of the catheter sheath by adopting a data frame, wherein the point with the maximum amplitude intensity in each column of A-line data falling in the data frame is taken as a reference point.

2. The method of claim 1, wherein the fresnel reflected light power of the outer surface is relatively stable, which effectively avoids the problem of tissue birefringence image errors caused by instability of reflected light power of the biological tissue or sample surface.

Technical Field

The invention relates to the field of catheter imaging covering cardiovascular and cerebrovascular systems and the like by catheter Optical Coherence Tomography (OCT), in particular to a method for improving the demodulation effect of the catheter Polarization-sensitive OCT (Polarization-sensitive OCT), namely the birefringence information of a demodulation sample in a PS-OCT image.

Background

The catheter OCT imaging technology is a blood vessel imaging method with the highest image resolution at present, particularly the catheter PS-OCT imaging technology, can solve the medical problem that the stability of atherosclerotic plaques is difficult to judge in vivo, in real time and rapidly, and can improve the prevention and treatment effect of atherosclerotic diseases. However, the existing OCT system has reached a level that may determine the property of the tissue plaque in terms of resolution, but is still insufficient in terms of tissue penetration ability, image sharpness, and accuracy of tissue plaque type determination, and using the PS-OCT technology, improving the performance of the related technology is a key direction for development of the OCT system, and is also a necessary way to solve the aforementioned key scientific problems.

In catheter OCT, catheter PS-OCT is an extension of catheter OCT technology, which provides a quantitative measure of tissue birefringence properties. The birefringence of light changes the polarization state of light and can be associated with proteins and biological macromolecules with oriented structures such as collagen, actin, and the like. The enhanced birefringence phenomenon of catheter PS-OCT is closely related to the existence of a large amount of thick collagen fibers or intimal smooth muscle cells, so that the high-resolution detection of catheter PS-OCT imaging can be applied to the enhanced plaque stability measurement. In addition, catheter PS-OCT systems have the potential to assess plaque collagen and differentiate normal intima, fibrous plaque, lipid plaque, and calcified plaque, among others.

In the catheter-based PS-OCT system, since the rotation of the catheter during imaging causes the birefringence information of the signal and the random birefringence information caused by the rotation of the catheter to be mixed together and difficult to distinguish, the reflected signal of a reference plane needs to be selected to compensate the random birefringence information introduced by the rotation of the catheter. The requirements for this reference plane are: has stable signal strength; the reflected signal carries random birefringence information introduced by catheter rotation; is easy to extract. The signal sources that satisfy these three requirements are mainly: the front surface of the catheter, the back surface of the catheter and the boundary of the tissues such as blood vessels. Since the boundary extraction of the vascular tissue depends on the imaging effect and the vascular tissue itself carries some birefringence information, interference is introduced.

Disclosure of Invention

The invention aims to provide a method for improving the demodulation effect of catheter polarization-sensitive Optical Coherence Tomography (OCT), aiming at the problem that the polarization resolution is seriously influenced by a plurality of reference surfaces in the conventional demodulation process of the catheter polarization-sensitive OCT

The technical scheme of the invention is as follows:

a method for improving the demodulation effect of polarization-sensitive optical coherence tomography of a catheter is characterized in that the outer surface of a catheter sheath is selected as a reference surface before polarization calculation, and the reference surface is not influenced by a sample to be detected; and selecting the position of the outer surface of the catheter sheath by adopting a data frame, wherein the point with the maximum amplitude intensity in each column of A-line data falling in the data frame is taken as a reference point.

The Fresnel reflection optical power of the reference surface is relatively stable, and the problem of tissue birefringence image error caused by unstable reflection optical power of biological tissues or sample surfaces can be effectively avoided.

The invention has the beneficial effects that:

the method can obviously improve the accuracy of the polarization calculation result and improve the analysis speed.

Drawings

FIG. 1 is a schematic representation of birefringence information extracted using the inner surface of a catheter as a reference plane.

FIG. 2 is a schematic representation of birefringence information extracted using the outer surface of a catheter as a reference plane.

Detailed Description

The invention is further described below with reference to the figures and examples.

As shown in fig. 2.

A method for improving demodulation effect of polarization-sensitive optical coherence tomography of a catheter is characterized in that the outer surface of a catheter sheath is selected as a reference surface before polarization resolving is carried out, and the reference surface is not influenced by a sample to be detected; and selecting the position of the outer surface of the catheter sheath by adopting a data frame, wherein the point with the maximum amplitude intensity in each column of A-line data falling in the data frame is taken as a reference point. The Fresnel reflection optical power of the reference surface is relatively stable, and the problem of tissue birefringence image error caused by unstable reflection optical power of biological tissues or sample surfaces can be effectively avoided.

Only the inner and outer surfaces of the catheter are generally considered as objects of study during the actual analysis process. Experiments show that the selection of the reference surface influences the result of polarization solution, as shown in fig. 1, it can be seen that the polarization contrast of the area selected in the box is reduced, and the result of polarization solution is misaligned.

As can be seen from FIG. 1, the selection of different reference planes and the polarization solution for tissue birefringence are different, which illustrates that the selection of the reference planes is important. The outer surface of the optical fiber conduit is selected as a reference surface because the optical power of Fresnel reflection of the optical fiber conduit is relatively stable, and the problem of tissue birefringence image error caused by unstable reflected optical power of a biological tissue or a sample surface can be effectively solved.

The parts not involved in the present invention are the same as or can be implemented using the prior art.