CN111436910B - Optical coherence tomography multi-mode imaging device and method for living tissue - Google Patents

Optical coherence tomography multi-mode imaging device and method for living tissue Download PDF

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CN111436910B
CN111436910B CN202010348482.5A CN202010348482A CN111436910B CN 111436910 B CN111436910 B CN 111436910B CN 202010348482 A CN202010348482 A CN 202010348482A CN 111436910 B CN111436910 B CN 111436910B
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CN111436910A (en
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朱疆
樊凡
祝连庆
杨强
王重阳
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Beijing Information Science and Technology University
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    • A61B3/1225—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for looking at the eye fundus, e.g. ophthalmoscopes using coherent radiation
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    • A61B3/1241—Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions for looking at the eye fundus, e.g. ophthalmoscopes specially adapted for observation of ocular blood flow, e.g. by fluorescein angiography
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Abstract

The invention provides an optical coherence tomography multi-mode imaging device and method of living tissue, after obtaining a first complex signal sequence group before the sound radiation force acts on all detection positions of the living tissue and a second complex signal sequence group after the sound radiation force acts on the detection positions; and constructing a structural image of the living tissue, an elastic image of the living tissue and a plurality of image combinations in a blood flow image of the living tissue according to the first complex signal sequence group and/or the second complex signal sequence group corresponding to all detection positions. The optical coherence tomography multi-mode imaging method provided by the invention can construct a plurality of image combinations in the structure image, the elastic image and the blood flow image of the living tissue, so that the corresponding information of the structure, the elastic distribution and the blood flow distribution of the living tissue can be measured simultaneously, and the accuracy of disease diagnosis of the living tissue is improved.

Description

Optical coherence tomography multi-mode imaging device and method for living tissue
Technical Field
The invention relates to the technical field of medical instruments, in particular to an optical coherence tomography multi-mode imaging device and method for living tissues.
Background
The difference of elastomechanical characteristics of biological tissues is derived from the difference of components, structures and interactions of biological molecules, cells and tissues, and the elastometry of the biological tissues has important significance for evaluating the physiological functions of the tissues, and can be used for diagnosing diseases of parts such as eyeballs, cardiovascular diseases, mammary glands, livers and the like. The blood flow has important significance for maintaining the normal physiological functions of the organism, the blood flow distribution can prompt the state of biological tissues, and the blood flow radiography can be used for diagnosing tumors and vascular abnormality diseases and researching brain functions. The structure of the biological tissue can intuitively represent whether the biological structure is abnormal or not. There is an urgent need for a multi-modality imaging technique for simultaneously acquiring structural images, elastic images and blood flow images of biological tissues, so as to facilitate accurate diagnosis of diseases of the biological tissues.
Disclosure of Invention
In view of the above, the present invention provides an optical coherence tomography (Optical coherence tomography, OCT) multi-modality imaging apparatus and method for living tissue, which effectively solve the technical problems existing in the prior art and improve the accuracy of disease diagnosis for living tissue.
In order to achieve the above purpose, the technical scheme provided by the invention is as follows:
An optical coherence tomography multi-modality imaging method of living tissue, comprising the steps of:
s1, dividing weak coherent light beams with different wavelengths in a preset wave band into a reference beam and a detection beam, controlling the detection beam to irradiate a detection position of the surface of the living tissue to generate a feedback beam, controlling the reference beam to irradiate a reflecting mirror to generate a reflected beam, controlling the interference of the feedback beam and the reflected beam to generate an interference beam, extracting an interference signal sequence corresponding to the change of the wavelength in the interference beam, and performing Fourier transformation to obtain a first complex signal sequence of the detection position corresponding to the change of the depth, thereby obtaining a first complex signal sequence group comprising a plurality of first complex signal sequences corresponding to a plurality of time points corresponding to the change of the depth;
s2, generating an acoustic radiation force to act on a fixed receiving position of the living tissue, and obtaining a second complex sequence group of a plurality of second complex signal sequences, which correspondingly change with depth at a plurality of time points, of the detecting position after the acoustic radiation force acts in a step S1 mode;
s3, repeating the steps S1 and S2 until the scanning of all detection positions of the detection light beam on the surface of the living tissue is completed, and obtaining all first complex signal sequence groups of all detection positions of the living tissue before the action of the acoustic radiation force and all second complex signal sequence groups after the action;
S4, constructing a structural image of the living tissue, an elastic image of the living tissue and a plurality of image combinations in a blood flow image of the living tissue according to the first complex signal sequence group and/or the second complex signal sequence group corresponding to all detection positions.
Correspondingly, the invention also provides an optical coherence tomography multi-mode imaging device of living tissues, which comprises: an optical coherence tomography unit and an acoustic radiation force excitation unit;
the acoustic radiation force excitation unit is used for generating an acoustic radiation force to act on a fixed receiving position of the living tissue;
the optical coherence tomography unit is used for dividing weak coherent light beams with different wavelengths in a preset wave band into a reference beam and a detection beam before the acoustic radiation force acts on a fixed receiving position of the living tissue, controlling the detection position of the detection beam irradiated on the surface of the living tissue to generate a feedback beam, controlling the reference beam to be irradiated on a reflecting mirror to generate a reflecting beam, controlling the feedback beam and the reflecting beam to interfere to generate an interference beam, extracting an interference signal sequence corresponding to the interference beam and changing along with the wavelength, and performing Fourier transformation to obtain a first complex signal sequence of the detection position along with the depth, thereby obtaining a first complex signal sequence group comprising a plurality of first complex signal sequences corresponding to a plurality of time points and changing along with the depth; and obtaining a set of detection positions in the above manner after the acoustic radiation force acts on the fixed receiving position of the living tissue, the set of detection positions comprising a plurality of second plurality of signal sequences corresponding to a plurality of time points that vary with depth after the acoustic radiation force acts on the plurality of second plurality of signal sequences; repeating the above process until the scanning of all detection positions of the detection light beam on the surface of the living tissue is completed, and obtaining all first complex signal sequence groups of all detection positions of the living tissue before the action of the acoustic radiation force and all second complex signal sequence groups after the action; and constructing a structural image of the living tissue, an elastic image of the living tissue and a plurality of image combinations in a blood flow image of the living tissue according to the first complex signal sequence group and/or the second complex signal sequence group corresponding to all detection positions.
Compared with the prior art, the technical scheme provided by the invention has at least the following advantages:
the invention provides an optical coherence tomography multi-mode imaging method of living tissues, which comprises the following steps: s1, dividing weak coherent light beams with different wavelengths in a preset wave band into a reference beam and a detection beam, controlling the detection beam to irradiate a detection position of the surface of the living tissue to generate a feedback beam, controlling the reference beam to irradiate a reflecting mirror to generate a reflected beam, controlling the interference of the feedback beam and the reflected beam to generate an interference beam, extracting an interference signal sequence corresponding to the change of the wavelength in the interference beam, and performing Fourier transformation to obtain a first complex signal sequence of the detection position corresponding to the change of the depth, thereby obtaining a first complex signal sequence group comprising a plurality of first complex signal sequences corresponding to a plurality of time points corresponding to the change of the depth; s2, generating an acoustic radiation force to act on a fixed receiving position of the living tissue, and obtaining a second complex sequence group of a plurality of second complex signal sequences, which correspondingly change with depth at a plurality of time points, of the detecting position after the acoustic radiation force acts in a step S1 mode; s3, repeating the steps S1 and S2 until the scanning of all detection positions of the detection light beam on the surface of the living tissue is completed, and obtaining all first complex signal sequence groups of all detection positions of the living tissue before the action of the acoustic radiation force and all second complex signal sequence groups after the action; s4, constructing a structural image of the living tissue, an elastic image of the living tissue and a plurality of image combinations in a blood flow image of the living tissue according to the first complex signal sequence group and/or the second complex signal sequence group corresponding to all detection positions. The optical coherence tomography multi-mode imaging method provided by the invention can construct a plurality of image combinations in the structure image, the elasticity image and the blood flow image of the living tissue, further can measure the corresponding information of the structure, the elasticity and the blood flow distribution of the living tissue at the same time, and improves the accuracy of disease diagnosis of the living tissue.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for optical coherence tomography of living tissue according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of an optical coherence tomography multi-mode imaging device for living tissue according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of another optical coherence tomography multi-modality imaging apparatus for living tissue according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a multi-modality imaging device for optical coherence tomography of living tissue according to another embodiment of the present invention;
FIG. 5 is a schematic view of a probe beam and a living tissue according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of the transformation of an interference signal sequence and a complex signal sequence according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a structure of different scanning modes for imaging a structure according to an embodiment of the present invention;
FIG. 8 is a view of a blood flow image and projection thereof before the application of acoustic radiation force according to an embodiment of the present invention;
fig. 9 is a schematic diagram of four-dimensional (x, y, z, t) signal acquisition and vibration image construction after the acoustic radiation force is applied according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
As described in the background art, the elastomechanical property difference of biological tissues is derived from the difference of components, structures and interactions of biological molecules, cells and tissues, and the elastometry of the biological tissues has important significance for evaluating the physiological functions of the tissues and can be used for diagnosing diseases of parts such as eyeballs, cardiovascular diseases, mammary glands, livers and the like. The blood flow has important significance for maintaining the normal physiological functions of the organism, the blood flow distribution can prompt the state of biological tissues, and the blood flow radiography can be used for diagnosing tumors and vascular abnormality diseases and researching brain functions. The structure of the biological tissue can intuitively represent whether the biological structure is abnormal or not. There is an urgent need for a multi-modality imaging technique for simultaneously acquiring structural images, elastic images and blood flow images of biological tissues, so as to facilitate accurate diagnosis of diseases of the biological tissues.
For example, current diagnosis of ocular fundus diseases relies mainly on imaging of ocular fundus structures and blood vessels, and for Age-related macular degeneration (Age-related macular degeneration, AMD) diseases, clinical diagnosis methods of Age-related macular degeneration are mainly based on ocular fundus angiography imaging, including fluorescein ocular fundus angiography (Fundus fluorescein angiography, FFA), chorioindoline bluish-green imaging (Indocyanine green angiography, ICGA) and optical coherence tomography (Optical coherence tomography, OCT). During FFA radiography, a fluorescein sodium solution is injected intravenously, then fundus blood vessel images are shot by a fundus camera, and the abnormity of fundus blood vessel structures is observed. However, FFA has difficulty in clearly imaging the choroidal blood vessels because they are blocked by the retinal pigment epithelium. To achieve clearer choroidal angiography, ICGA techniques are evolving. ICGA records blood flow dynamic images in choroidal blood vessels by scanning a fundus mirror with a near infrared fundus camera or laser using indocyanine green (Indocyanine green, ICG) as a dye and near infrared light as an excitation light source. FFA and ICGA are both invasive procedures, there is a risk of infection and allergy, and contrast agent allergy and renal insufficiency are contraindications for FFA and ICGA. Therefore, a non-invasive, label-free high-resolution three-dimensional medical imaging technology is urgently needed at present, and a multi-mode imaging technology for simultaneously acquiring a structural image, an elastic image and a blood flow image of living tissues is needed, so that accurate diagnosis of biological tissue diseases is facilitated.
Based on the above, the invention provides the optical coherence tomography multi-mode imaging device and the method for the living tissue, which effectively solve the technical problems existing in the prior art and improve the accuracy of disease diagnosis of the living tissue.
In order to achieve the above objective, the technical solution provided by the present invention is described in detail below, specifically with reference to fig. 1 to 9.
Referring to fig. 1, a flowchart of an optical coherence tomography multi-mode imaging method for living tissue according to an embodiment of the present invention includes the steps of:
s1, dividing weak coherent light beams with different wavelengths in a preset wave band into a reference beam and a detection beam, controlling the detection beam to irradiate a detection position of the surface of the living tissue to generate a feedback beam, controlling the reference beam to irradiate a reflecting mirror to generate a reflected beam, controlling the interference of the feedback beam and the reflected beam to generate an interference beam, extracting an interference signal sequence corresponding to the change of the wavelength in the interference beam, and carrying out Fourier transformation to obtain a first complex signal sequence of the detection position corresponding to the change of the depth, thereby obtaining a first complex signal sequence group comprising a plurality of first complex signal sequences corresponding to a plurality of time points corresponding to the change of the depth.
S2, generating an acoustic radiation force to act on the fixed receiving position of the living tissue, and obtaining a second complex sequence group of a plurality of second complex signal sequences, which correspondingly change with depth at a plurality of time points, of the detecting position after the acoustic radiation force acts in a step S1 mode. S3, repeating the steps S1 and S2 until the scanning of all detection positions of the detection light beam on the surface of the living tissue is completed, and obtaining all first complex signal sequence groups of all detection positions of the living tissue before the action of the acoustic radiation force and all second complex signal sequence groups after the action. Wherein a detection position corresponds to a first plurality of signal sequence sets and a detection position corresponds to a second plurality of signal sequence sets. And, in a first complex signal sequence group, the time points are in one-to-one correspondence with the first complex signal sequences; and in a second complex signal sequence group, the time points are in one-to-one correspondence with the second complex signal sequences. It will be appreciated that each value in a complex signal sequence represents a complex signal of a certain depth, a complex signal sequence being identifiable as being acquired at the same point in time; the plurality of complex signal sequences in a complex signal sequence group are acquired at respective corresponding time points in a plurality of time points.
S4, constructing a structural image of the living tissue, an elastic image of the living tissue and a plurality of image combinations in a blood flow image of the living tissue according to the first complex signal sequence group and/or the second complex signal sequence group corresponding to all detection positions.
In an embodiment of the present invention, the method constructs a combination of multiple images among a structural image of the living tissue, an elastic image of the living tissue, and a blood flow image of the living tissue according to the first complex signal sequence group and/or the second complex signal sequence corresponding to all detection positions, including:
and constructing a plurality of image combinations in the structural image of the living tissue, the elastic image of the living tissue and the blood flow image of the living tissue according to the first complex signal sequence group corresponding to the first preset time period before the radiation force is acted on and/or the second complex signal sequence group corresponding to the second preset time period after the radiation force is acted on.
It can be understood that the technical scheme provided by the invention can intercept and analyze the complex signal sequence of a period before the action of the sound radiation force and the complex signal sequence of a period after the action of the sound radiation force so as to achieve the purpose of constructing the corresponding image of the living tissue. That is, the present invention performs data acquisition for all detection positions at a plurality of time points which are fixed time points. The plurality of time points corresponding to the first complex signal sequence group are all in a first preset time period, and the plurality of time points corresponding to the second complex signal sequence group are all in a second preset time period. Specifically, at the same detection position, a first complex signal sequence which changes with depth and is at least 2 time points before the action of the acoustic radiation force and a second complex signal sequence which changes with depth and is at least 2 time points after the action of the acoustic radiation force can be obtained, and further, according to the obtained complex signal sequences of multiple groups of different time points, the blood flow and/or vibration condition of living tissues can be analyzed by analyzing the changes of the complex signal sequences of different time points.
In an embodiment of the invention, the invention can construct structural images of the living tissue at any time point and also can construct structural images of the living tissue at different time points. The method for specifically constructing the structure image of the living tissue comprises the following steps: and constructing structural images of the living tissue at the same time point according to the first complex signal sequences corresponding to all detection positions at the same time point or the second complex signal sequences corresponding to all detection positions at the same time point.
And/or constructing structural images of the living tissue at different time points according to the first complex signal sequences corresponding to all detection positions at different time points or according to the second complex signal sequences corresponding to all detection positions at different time points.
It can be appreciated that the embodiment of the present invention can determine the depth-dependent structural data of the probe position at any time point according to the depth-dependent complex signal sequence (the first complex signal sequence or the second complex signal sequence) of the probe position at any time point. Further, it is possible to construct structural images of living tissue at the same point in time from the structural data corresponding to the depth change at the same point in time of all the detection positions. Alternatively, structural images of the living tissue at different points in time can be constructed from the corresponding depth-dependent structural data of all the detection positions at different points in time.
The embodiment of the invention particularly provides a method for determining corresponding structure data of a detection position, namely, according to any one of a first complex signal sequence and a second complex signal sequence corresponding to the detection position, determining the structure data of the detection position changing with depth at any time point comprises the following steps:
and determining structural data of the detection position changing with depth at any time point according to the amplitude of the complex signals in the complex signal sequence, wherein the structural data of the detection position changing with depth at any time point is used for constructing a structural image of the living tissue according to the structural data corresponding to all the detection positions.
In an embodiment of the present invention, the present invention provides a method for constructing a blood flow image, that is, determining blood flow data of a detection position changing with depth at different time points according to a first complex signal sequence corresponding to the same detection position at different time points; and constructing blood flow images of the living tissue at different time points according to the blood flow data of all the detection positions which change with depth at different time points.
It can be appreciated that the embodiment of the present invention can determine the blood flow data of the detection position changing with depth at any time point according to the first complex signal sequence of the detection position changing with depth at any time point. Further, blood flow images of the living tissue at different time points are constructed from the blood flow data of all the detected positions corresponding to the depth change at different time points.
The embodiment of the invention particularly provides a method for determining blood flow data corresponding to a detection position, namely determining the blood flow data of the detection position changing with depth at any time point according to a first complex signal sequence corresponding to the detection position, comprising the following steps:
and determining blood flow data of the detection position changing with depth at any time point according to the amplitude and/or the phase of the complex signals in the first complex signal sequence of the detection position at any time point.
In an embodiment of the present invention, the present invention provides a method for constructing an elastic image, that is, determining vibration data of a detection position changing with depth at different time points according to a second complex signal sequence corresponding to the same detection position at different time points; determining vibration distribution images of the living tissue at different time points according to vibration data of all detection positions changing with depth at different time points; and constructing an elastic image of the living tissue according to vibration distribution images of the living tissue at different time points.
It can be appreciated that the embodiment of the invention can determine the vibration data of the detection position changing with the depth at any time point according to the second complex signal sequence changing with the depth at any time point of the detection position. Further, vibration distribution images of the living tissue at different time points are determined according to vibration data of all detection positions, which correspondingly change along with the depth, at different time points, and finally, an elastic image of the living tissue is constructed according to the vibration distribution images.
The embodiment of the invention particularly provides a method for determining vibration data corresponding to a detection position, namely, determining the vibration data of the detection position changing with depth at any time point according to a second complex signal sequence corresponding to the detection position, comprising the following steps:
and determining vibration data of the detection position changing with depth at any time point according to the amplitude and/or the phase of the complex signals in the second complex signal sequence of the detection position at any time point.
The embodiment of the invention specifically provides a method for constructing an elastic image according to vibration distribution images, namely, constructing the elastic image of the living tissue according to the vibration distribution images of the living tissue at different time points, comprising the following steps:
calculating elastic data of the living tissue according to vibration distribution images of the living tissue at different time points, wherein the elastic data comprises at least one of maximum amplitude, resonant frequency and elastic wave speed of the living tissue at different spatial positions;
and constructing an elastic image of the living tissue according to the elastic data.
In any of the above embodiments of the present invention, the living tissue provided by the present invention is fundus tissue (fundus tissue includes retina, choroid, sclera, etc.), cerebral cortex tissue, and skin tissue, and the present invention is not particularly limited thereto.
Referring to fig. 2, a schematic structural diagram of an optical coherence tomography multi-mode imaging device for living tissue according to an embodiment of the present invention is shown, where the optical coherence tomography multi-mode imaging device includes: an optical coherence tomography unit 100 and an acoustic radiation force excitation unit 200.
The acoustic radiation force excitation unit 100 is configured to generate an acoustic radiation force to be applied to a fixed receiving position of the living tissue 300.
The optical coherence tomography unit 200 is configured to divide weak coherent light beams with different wavelengths in a predetermined wavelength band into a reference beam and a probe beam before an acoustic radiation force acts on a fixed receiving position of a living tissue, control the probe beam to irradiate the probe position on the surface of the living tissue to generate a feedback beam, control the reference beam to irradiate a reflecting mirror to generate a reflected beam, control the feedback beam and the reflected beam to interfere to generate an interference beam, extract an interference signal sequence corresponding to the wavelength change in the interference beam, and perform fourier transform to obtain a first complex signal sequence of the probe position changing with depth, thereby obtaining a first complex signal sequence group including a plurality of first complex signal sequences of which a plurality of time points are corresponding to the depth change; and obtaining a set of detection positions in the above manner after the acoustic radiation force acts on the fixed receiving position of the living tissue, the set of detection positions comprising a plurality of second plurality of signal sequences corresponding to a plurality of time points that vary with depth after the acoustic radiation force acts on the plurality of second plurality of signal sequences; repeating the above process until the scanning of all detection positions of the detection light beam on the surface of the living tissue is completed, and obtaining all first complex signal sequence groups of all detection positions of the living tissue before the action of the acoustic radiation force and all second complex signal sequence groups after the action; and constructing a structural image of the living tissue, an elastic image of the living tissue and a plurality of image combinations in a blood flow image of the living tissue according to the first complex signal sequence group and/or the second complex signal sequence group corresponding to all detection positions.
The device and the method provided by the embodiment of the invention realize the bimodal imaging of the blood flow image and the elastic image or the multimodal imaging of the structure image, the elastic image, the three-modality imaging of the blood flow image and the like, provide more tissue structure and function information and are more beneficial to the diagnosis of diseases.
In an embodiment of the present invention, the optical coherence tomography multi-mode imaging device provided in the embodiment of the present invention may be a swept OCT imaging structure. Referring to fig. 3, a schematic structural diagram of another optical coherence tomography multi-mode imaging device for living tissue according to an embodiment of the present invention is shown, where the optical coherence tomography unit 100 provided by the embodiment of the present invention includes: the device comprises a sweep frequency light source 101, a first optical fiber coupler 102, a first optical fiber circulator 103, a second optical fiber circulator 113, a second optical fiber coupler 104, a first reflecting mirror 105, a photoelectric detector 106 and an upper computer 107. The first optical fiber coupler 102 provided in the embodiment of the present invention may be an optical fiber coupler with a spectral ratio of 99/1, 90/10 or 80/20, and the second optical fiber coupler may be an optical fiber coupler with a spectral ratio of 50/50.
The swept optical source 101 is configured to output a weak coherent light beam with a different wavelength within a predetermined wavelength band.
The first fiber coupler 102 is configured to split the swept weak coherent laser light into the reference beam and the probe beam.
The first fiber circulator 103 is configured to transmit the reference beam to the first mirror 105, and transmit the reflected beam reflected by the first mirror 105 to the second fiber coupler 104; and the second fiber circulator 113 is configured to generate a feedback beam for transmitting the probe beam to a probe position of the surface of the living tissue 300, and transmit the feedback beam to the second fiber coupler 104.
The second fiber coupler 104 is configured to interfere the reflected light beam with the feedback light beam to generate an interference light beam.
The photodetector 106 is configured to detect the interference beam, convert the interference beam into an electrical signal, and transmit the electrical signal to the upper computer 107, where the upper computer 107 is configured to extract an interference signal sequence corresponding to a change with wavelength in the interference beam before the acoustic radiation force acts on a fixed receiving position of the living tissue, and perform fourier transform to obtain a first complex signal sequence of the detection position corresponding to a change with depth, so as to obtain a first complex signal sequence group including a plurality of first complex signal sequences corresponding to a plurality of time points corresponding to a change with depth; and obtaining a second plurality of series group of a plurality of second plurality of signal series including a plurality of time points corresponding to the change with depth after the acoustic radiation force is applied to the fixed receiving position of the living tissue in the above manner. Repeating the above process until the scanning of all detection positions of the detection light beam on the surface of the living tissue is completed, and obtaining all first complex signal sequence groups of all detection positions of the living tissue before the action of the acoustic radiation force and all second complex signal sequence groups after the action. And finally, constructing a structural image of the living tissue, an elastic image of the living tissue and a plurality of image combinations in a blood flow image of the living tissue according to the first complex signal sequence group and/or the second complex signal sequence group corresponding to all detection positions.
Further, in order to improve the performance of the optical coherence tomography multi-mode imaging device, as shown in fig. 3, the optical coherence tomography unit 100 provided in the embodiment of the present invention further includes: a first collimator lens 108, a first focusing lens 109, a second collimator lens 110, a first scanning galvanometer 111, and a scanning lens 112.
The first collimating lens 108 and the first focusing lens 109 are disposed in the optical path between the first fiber circulator 103 and the first reflecting mirror 105, and the first focusing lens 109 is disposed in the optical path between the first collimating lens 108 and the first reflecting mirror 105.
And the second collimating mirror 110, the first scanning galvanometer 111 and the scanning lens 112 are arranged on an optical path between the second optical fiber circulator 113 and the living tissue 300, the first scanning galvanometer 111 is arranged on an optical path between the second collimating mirror 110 and the scanning lens 112, and the scanning lens 112 is arranged on an optical path between the first scanning galvanometer 111 and the living tissue 300.
It can be understood that in the swept OCT imaging structure provided by the embodiments of the present invention, the swept weak coherent laser output by the swept light source is split into the reference beam and the probe beam by the first optical fiber coupler, and then the reference beam enters the reference branch, and the probe beam enters the tissue branch. The reference beam enters the first reflector to reflect after passing through the first optical fiber circulator, the first collimating mirror and the first focusing lens, and the reflected light beam is reversely transmitted to the first optical fiber circulator according to an original light path and is transmitted to the second optical fiber coupler by the first optical fiber circulator. The detection light beam enters the detection position of the surface of the living tissue after passing through the second optical fiber circulator, the second collimating mirror, the first scanning vibrating mirror and the scanning lens to generate a feedback light beam, and the feedback light beam is reversely transmitted to the second optical fiber circulator according to the entering light path of the detection light beam and is transmitted to the second optical fiber coupler by the optical fiber circulator. The second optical fiber coupler is used for generating an interference light beam by interfering the reference light beam and the feedback light beam, and the double-balanced amplified photoelectric detector is used for detecting and converting the interference light beam and the feedback light beam into an electric signal and then transmitting the electric signal to the upper computer. And the upper computer processes and constructs a plurality of image combinations in the structural image, the elastic image and the blood flow image according to the first complex signal sequence group before the action of the acoustic radiation force and/or the second complex signal sequence group after the action of the acoustic radiation force, which are obtained by processing the electric signals.
In an embodiment of the present invention, the optical coherence tomography multi-mode imaging device provided in the embodiment of the present invention may be a spectral domain OCT imaging structure. Referring to fig. 4, a schematic structural diagram of an optical coherence tomography multi-mode imaging device for a living tissue according to an embodiment of the present invention is shown, wherein the optical coherence tomography unit 100 according to the embodiment of the present invention includes: a continuous spectrum light source 121, a third fiber coupler 122, a second reflecting mirror 123, a grating 124, a camera 125 and a host computer 126. The third optical fiber coupler provided by the embodiment of the invention can be an optical fiber coupler with the split ratio of 90/10 and 80/20.
The continuous spectrum light source 121 is configured to output continuous spectrum weak coherent light as weak coherent light beams with different wavelengths within a predetermined wavelength band.
The third fiber coupler 122 is configured to split the continuous spectrum weak coherent light beam into the reference beam and the probe beam; the second reflecting mirror 123 is configured to receive the reference beam and reflect the reference beam as a reflected beam, and the detection position of the living tissue receives the detection beam and generates a feedback beam; and, the third fiber coupler 122 is configured to interfere the reflected light beam reflected by the second reflecting mirror 123 with the feedback light beam to generate an interference light beam.
The grating 124 is configured to split the interference beam and transmit the split interference beam to the camera 125, the camera 125 is configured to perform photoelectric conversion and transmit the split interference beam to the upper computer 126, and the upper computer 126 is configured to extract an interference signal sequence corresponding to a wavelength change in the interference beam before an acoustic radiation force acts on a fixed receiving position of a living tissue, and perform fourier transform to obtain a first complex signal sequence corresponding to a depth change in the detection position, so as to obtain a first complex signal sequence group including a plurality of first complex signal sequences corresponding to a plurality of time points and changing with the depth; and obtaining a second plurality of series group of a plurality of second plurality of signal series including a plurality of time points corresponding to the change with depth after the acoustic radiation force is applied to the fixed receiving position of the living tissue in the above manner. Repeating the above process until the scanning of all detection positions of the detection light beam on the surface of the living tissue is completed, and obtaining all first complex signal sequence groups of all detection positions of the living tissue before the action of the acoustic radiation force and all second complex signal sequence groups after the action. And finally, constructing a structural image of the living tissue, an elastic image of the living tissue and a plurality of image combinations in a blood flow image of the living tissue according to the first complex signal sequence group and/or the second complex signal sequence group corresponding to all detection positions.
Further, in order to improve the performance of the optical coherence tomography multi-mode imaging device, as shown in fig. 4, the optical coherence tomography unit 100 provided in the embodiment of the present invention further includes: isolator 127, third collimator 128, attenuator 129, first lens 130, fourth collimator 131, second scanning galvanometer 132, second lens 133, fifth collimator 134, third lens 135, and fourth lens 136 for unidirectional light transmission.
The isolator 127 is disposed in the optical path between the continuous spectrum light source 121 and the third fiber coupler 122.
The third collimating mirror 128, the attenuator 129 and the first lens 130 are disposed in an optical path between the third fiber coupler 122 and the second reflecting mirror 123, the attenuator 129 is disposed in an optical path between the third collimating mirror 128 and the first lens 130, and the first lens 130 is disposed in an optical path between the attenuator 129 and the second reflecting mirror 123.
The fourth collimating mirror 131, the second scanning galvanometer 132 and the second lens 133 are disposed on an optical path between the third fiber coupler 122 and the living tissue 300, the second scanning galvanometer 132 is disposed on an optical path between the fourth collimating mirror 131 and the second lens 133, and the second lens 133 is disposed on an optical path between the second scanning galvanometer 132 and the living tissue 300.
The fifth collimating lens 134 and the third lens 135 are disposed in the optical path between the third fiber coupler 122 and the grating 124, and the third lens 135 is disposed in the optical path between the fifth collimating lens 134 and the grating 124.
And, the fourth lens 136 is disposed on the optical path between the grating 124 and the camera 125.
It can be understood that in the spectral domain OCT imaging structure provided by the embodiments of the present invention, after the continuous spectrum weak coherent light output by the continuous spectrum light source passes through the isolator, the continuous spectrum weak coherent light is split into the reference beam and the probe beam by the third optical fiber coupler, where the reference beam enters the reference branch, and the probe beam enters the tissue branch. The reference beam enters the second reflecting mirror after passing through the third collimating mirror, the attenuator and the first lens, and the reflected light beam is reversely transmitted to the third optical fiber coupler according to the original light path. The detection light beam enters living tissue to generate a feedback light beam after passing through the fourth collimating mirror, the second scanning vibrating mirror and the second lens, and the feedback light beam is reversely transmitted to the third optical fiber coupler according to the entering light path of the detection light beam. The third optical fiber coupler is used for generating an interference light beam by interfering the reflected light beam and the feedback light beam, and the interference light beam enters the grating for splitting after passing through the fifth collimating mirror and the third lens, so that interference light with different wavelengths are spatially separated; and then photoelectric conversion is carried out on the camera after passing through the fourth lens, and the upper computer processes and constructs a plurality of image combinations in the structural image, the elastic image and the blood flow image according to the first complex signal sequence group before the action of the acoustic radiation force and/or the second complex signal sequence group after the action of the acoustic radiation force, which are obtained by processing the electric signals.
As shown in fig. 3 and 4, the acoustic radiation force excitation unit 200 according to the embodiment of the present invention includes: a signal source 210, an amplifier 220, and an ultrasonic transducer 230.
The signal source 210 is configured to generate a high-frequency periodic signal;
the amplifier 220 is configured to amplify the high-frequency periodic signal;
and, the ultrasonic transducer 230 is configured to generate the acoustic radiation force to act on the fixed receiving position of the living tissue 300 after receiving the high-frequency periodic signal.
In an embodiment of the present invention, the signal source 210 includes a waveform generator for generating the detection signal of a sine wave, a square wave or a triangle wave with high frequency.
It can be understood that in the acoustic radiation force excitation unit provided by the embodiment of the invention, the waveform generator generates high-frequency sine waves, square waves or triangular waves, and the ultrasonic transducer is driven after the high-frequency sine waves, square waves or triangular waves are amplified by the amplifier, so that the remote mechanical excitation of living tissues is realized. When the living tissue is fundus tissue, the waveform generator generates high-frequency sine waves, square waves or triangular waves, and the high-frequency sine waves, the square waves or the triangular waves are amplified by the amplifier to drive the ultrasonic transducer, so that remote mechanical excitation of fundus tissue is realized; specifically, the ultrasonic transducer enters the eyeball through an ultrasonic coupling material (water or ultrasonic gel) to form an acoustic radiation force field on the fundus, so as to induce micro vibration of fundus tissues; the ultrasonic can penetrate eye tissues such as cornea, crystalline lens and the like, is directly focused on the fundus to generate sound radiation force, and has the advantages of no wound, non-contact, accurate focusing and the like.
The signal processing procedure of the technical scheme provided by the embodiment of the invention is described in more detail below. Referring to fig. 5 and fig. 6, fig. 5 is a schematic structural diagram of a probe beam and a living tissue according to an embodiment of the present invention, and fig. 6 is a schematic transformation diagram of an interference signal sequence and a complex signal sequence according to an embodiment of the present invention. Wherein, the upper computer provided by the embodiment of the invention collects an interference signal sequence Γ of a certain lateral position (x, y) changing along with wavelength lambda at time t x，y，t (lambda), removing noise by filtering, and then Fourier transforming to frequency domain to obtain complex signal sequence F changing along with depth z at position (x, y) and time t x，y，t (Z) (first complex signal sequence or second complex signal sequence). Thus, at time t, the complex signal of spatial position (x, y, z) can be represented asComprising amplitude A x，y，z，t Part and phase->Part(s). Where (x, y) denotes coordinates of a plane perpendicular to the probe beam, and z denotes coordinates of a probe beam direction (depth direction), as shown in fig. 5. In FIG. 6->Representing the position (x, y) time t 1 An interference signal sequence that varies with wavelength λ; />Representing the position (x, y) time t 2 An interference signal sequence that varies with wavelength λ; / >Representing the position (x, y) time t 1 A complex signal sequence that varies with depth z; />Representing the position (x, y) time t 2 A complex signal sequence that varies with depth z.
Thus, after the amplitude and phase of the complex signals in the complex signal sequence are obtained, the structural data can be determined according to the amplitude of the complex signals, the blood flow data can be determined according to the amplitude and/or phase of the complex signals, and the vibration data can be determined according to the amplitude and/or phase of the complex signals.
Referring to fig. 7, a schematic structural diagram of different scanning modes of the structure imaging provided by the embodiment of the invention is shown, and when the structure imaging of the living tissue is performed, amplitude information of complex signals in a complex signal sequence is extracted, a scan is performed to obtain a one-dimensional image along a depth direction, B scan is performed to obtain a two-dimensional cross-sectional image, and C scan is performed to obtain a three-dimensional image.
The blood flow radiography imaging of the living tissue provided by the embodiment of the invention uses the light scattering change caused by the motion of the red blood cells in the blood flow to obtain the blood flow information and the high-resolution blood flow network image in the living tissue without marking. And acquiring a blood flow image by calculating the difference of the time sequence signals by utilizing the amplitude information and/or the phase information of the complex signals. In the following analysis, F is used t And F t+1 Complex signals representing the same three-dimensional spatial position (x, y, z) at time t and time t+1, angiographic imaging comprises the following imaging methods:
1. doppler phase analysis
The phase change of the complex signal can be used to calculate the vibration velocity and displacement of the light scattering particles in the living tissue. Velocity V of scattering particles in living tissue over time interval Δt and phase variation of complex signalThe relationship of (2) is as follows:
where n represents the optical refractive index of the living tissue, λ represents the center wavelength of the probe beam in vacuum, θ represents the angle between the particle motion direction and the probe beam, and v×cos (θ) represents the velocity component of the light scattering particles in the direction of the probe beam. Phase changeCan be calculated from complex signals as follows:
wherein Im represents the real part of the calculated complex number, re represents the imaginary part of the calculated complex number, F t And E is t+1 The complex signals at different times (T and t+1 times) and at the same spatial position are represented respectively, with a time interval at T and t+1 times being deltat.
2. Doppler intensity variance
I flow The flow rate is characterized, M representing the number of samples at the same spatial location.
3. Amplitude decorrelation
4. Doppler phase variance
5. Speckle variance
6. Intensity relative standard deviation
7. Intensity subtraction
8. Complex signal subtraction
Fig. 8 is a blood flow image and a projection chart thereof analyzed by the doppler intensity variance method according to an embodiment of the present invention. Before the acoustic radiation force acts, a three-dimensional blood flow image of the living tissue at the same time point and a projection image thereof are constructed according to blood flow data of all detection positions (x, y) changing with the depth z at the same time point.
The elasticity imaging of the living tissue provided by the embodiment of the invention is used for describing the property of the living tissue that the living tissue generates non-permanent deformation under the action of stress. The elastic modulus of the living tissue is calculated by the slope of the stress-strain curve during elastic deformation, and comprises Young's modulus, shear modulus, bulk modulus, compression modulus and the like. In biomedical applications, young's modulus and shear modulus are typically measured to assess the elastic properties of soft tissue. Meanwhile, to simplify tissue biomechanical properties, it is often assumed that the tissue is mechanically uniform and incompressible material in a small region. The ratio of load stress and small deformation strain remains constant in a small uniform region of incompressible elastic tissue, which is direction independent in isotropic tissue and direction dependent in anisotropic tissue.
From vibration measurement of living tissue to estimation of elastic properties, three methods provided by embodiments of the present invention include comparison of maximum vibration amplitude, measurement of resonance frequency, and calculation of elastic wave velocity. When the same pressure is applied to different tissues, the maximum vibration amplitudes can be directly compared to qualitatively evaluate the elastic properties, and softer tissues will exhibit larger vibration amplitudes. The resonance frequency is approximately linear with the square root of the Young's modulus, and the Young's modulus of the tissue can be calculated by measuring the resonance frequency of the tissue and comparing the measured curve. The elastic wave propagation velocity may also be measured, and the elastic modulus calculated based on a quantitative relationship between the wave velocity and the elastic modulus. When the elastic properties are calculated by the three methods, the OCT is required to detect the tiny vibration of the tissue, and the method for detecting the tiny vibration is consistent with the blood flow radiography algorithm. The three methods are specifically as follows:
1. comparison of maximum vibration amplitude
When the amplitude of the vibrations is detected by the Doppler phase analysis OCT method, the applied acoustic radiation force is generally parallel or oblique to the probe beam. Young's modulus E, an important parameter for the characterization of elastic properties in biomedical applications, is the ratio of stress sigma to strain epsilon, which can be described as:
Where F is the applied force, S is the area of the applied force, Δz is the change in tissue thickness in the direction of force application, z 0 Is the original thickness of the tissue in the direction of force application. When the external force is uniform over a range, the force F/S experienced per unit area of tissue is approximately the same. Due to small displacement of the object caused by external forces, the strain is made small enough (Deltaz/z 0 Less than 0.1%) can be considered to be z when vibrating 0 The relative Young's modulus can thus be approximated with Δz, which remains unchanged.
To calculate Δz, the OCT method can measure the vibration velocity V over the time interval Δt t The following is shown:
then from time t 1 To t 2 The amplitude Δz of the vibration parallel to the probe beam direction can be determined by the following equation:
the difference in relative young's modulus can be evaluated by the vibration amplitude Δz, the larger Δz, the smaller young's modulus.
2. Resonance frequency detection
When the viscosity is neglected and the deformation is relatively small (Δz/z 0 Less than 0.1%) as elastic material, soft tissue can be modeled by an elastic spring. The applied force F is proportional to Δz×k, where Δz is the displacement from the home position and k is the elastic constant. Young's modulus E may also be described by the following formula:
wherein f is the resonant frequency of the tissue, M is the mass of the tissue, z 0 Is the original thickness of the tissue in the direction of force application, S is the area of force applied. Therefore, the resonant frequency f of the tissue is linear with the square root of Young's modulus E and can be used to quantify Young's modulus. In order to measure the resonance frequency of the tissue, the frequency of the external force can be modulated, and the amplitude of the tissue is measured at different external force frequencies. The external force frequency corresponding to the maximum amplitude of the tissue is the resonance frequency of the tissue, namely the characteristic frequency of the tissue.
3. Elastic wave velocity calculation
When an external force excites tissue at one location, elastic waves may be generated that propagate from the excited location into or near the tissue. The elastic properties of tissue can be calculated using OCT to image the propagation of elastic waves and measuring the wave velocity. Elastic waves that propagate inside thick tissue are called bulk waves, including compression waves and shear waves. The elastic wave traveling near the surface at a depth of about one wavelength is a surface rayleigh wave.
Shear waves are most commonly used for elasticity measurements. Shear waves are transverse waves whose direction of propagation is perpendicular to the direction of the applied force (i.e., the direction of vibration). After excitation by an external force, shear waves exist inside the tissue. The shear modulus was calculated using the following method:
Where ρ is the density of the tissue, V s Is the wave velocity of the shear wave. Based on the relationship between the shear modulus μ and young's modulus E, i.e., e=2μ (1+v), the young's modulus of a uniformly isotropic tissue can be determined by:
where v is the poisson's ratio of the sample. For biological tissues, the poisson ratio is about 0.5, since they can be considered incompressible materials under small strains, young's modulus E is equal to 3ρ×v s 2 。
A compressional wave is a longitudinal wave that propagates in the direction of force (i.e., the direction of vibration) in a compressible medium. Velocity V of compressional waves in uniformly isotropic tissue c With respect to bulk modulus K, shear modulus μ and tissue density ρ, it can be determined by the following equation:
due to the high speed propagation of the compression wave and the relatively low sampling rate of current OCT systems, the speed of the compression wave is difficult to measure by OCT systems.
The surface Rayleigh wave propagates near the tissue surface. Rayleigh waves can be detected at a depth of about one wavelength. When the external force excitation site is close to the tissue surface, the detected elastic wave propagating along the tissue surface should be regarded as a rayleigh wave. For a uniform isotropic tissue, young's modulus E may be based on Rayleigh wave velocity V R The calculation formula is as follows:
where v is poisson's ratio and ρ is the density of the sample.
Fig. 9 is a schematic diagram of four-dimensional (x, y, z, t) signal acquisition and vibration image construction after the acoustic radiation force is applied according to an embodiment of the present invention. After generating an acoustic radiation force to act on the fixed receiving position of the living tissue, a post-acoustic radiation force detection position (x 1 ,y 1 ) A second complex signal sequence varying with depth z at different points in time t; then moving the OCT probe position to (x) 2 ,y 1 ) And generating again an acoustic radiation force acting on the fixed receiving position of the living tissue, obtaining a detection position (x 2 ,y 1 ) A second complex signal sequence varying with depth z at different points in time t; repeating the above steps to complete the detection of the position (x 3 ,y 1 ) And (x) 4 ,y 1 ) After data acquisition of (a), the y-coordinate is changed, and (x 1 ,y 2 )、(x 2 ,y 2 )、(x 3 ,y 2 ) And (x) 4 ,y 2 ) Thereby completing four-dimensional (x, y, z, t) data acquisition after the action of acoustic radiation force and constructing a space (x, y, z) vibration image changed along with time t.
The invention provides an optical coherence tomography multi-mode imaging device and method of living tissue,
the method comprises the following steps: s1, dividing weak coherent light beams with different wavelengths in a preset wave band into a reference beam and a detection beam, controlling the detection beam to irradiate a detection position of the surface of the living tissue to generate a feedback beam, controlling the reference beam to irradiate a reflecting mirror to generate a reflected beam, controlling the interference of the feedback beam and the reflected beam to generate an interference beam, extracting an interference signal sequence corresponding to the change of the wavelength in the interference beam, and performing Fourier transformation to obtain a first complex signal sequence of the detection position corresponding to the change of the depth, thereby obtaining a first complex signal sequence group comprising a plurality of first complex signal sequences corresponding to a plurality of time points corresponding to the change of the depth; s2, generating an acoustic radiation force to act on a fixed receiving position of the living tissue, and obtaining a second complex sequence group of a plurality of second complex signal sequences, which correspondingly change with depth at a plurality of time points, of the detecting position after the acoustic radiation force acts in a step S1 mode; s3, repeating the steps S1 and S2 until the scanning of all detection positions of the detection light beam on the surface of the living tissue is completed, and obtaining all first complex signal sequence groups of all detection positions of the living tissue before the action of the acoustic radiation force and all second complex signal sequence groups after the action; s4, constructing a structural image of the living tissue, an elastic image of the living tissue and a plurality of image combinations in a blood flow image of the living tissue according to the first complex signal sequence group and/or the second complex signal sequence group corresponding to all detection positions. The optical coherence tomography multi-mode imaging method provided by the invention can construct a plurality of image combinations in the structure image, the elasticity image and the blood flow image of the living tissue, further can measure the corresponding information of the structure, the elasticity and the blood flow distribution of the living tissue at the same time, and improves the accuracy of disease diagnosis of the living tissue.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (9)

1. An optical coherence tomography multi-modality imaging method of living tissue, comprising the steps of:
s1, dividing weak coherent light beams with different wavelengths in a preset wave band into a reference beam and a detection beam, controlling the detection beam to irradiate a detection position of the surface of the living tissue to generate a feedback beam, controlling the reference beam to irradiate a reflecting mirror to generate a reflected beam, controlling the interference of the feedback beam and the reflected beam to generate an interference beam, extracting an interference signal sequence corresponding to the change of the wavelength in the interference beam, and performing Fourier transformation to obtain a first complex signal sequence of the detection position corresponding to the change of the depth, thereby obtaining a first complex signal sequence group comprising a plurality of first complex signal sequences corresponding to a plurality of time points corresponding to the change of the depth;
S2, generating an acoustic radiation force to act on a fixed receiving position of the living tissue, and obtaining a second complex sequence group of a plurality of second complex signal sequences, which correspondingly change with depth at a plurality of time points, of the detecting position after the acoustic radiation force acts in a step S1 mode;
s3, repeating the steps S1 and S2 until the scanning of all detection positions of the detection light beam on the surface of the living tissue is completed, and obtaining all first complex signal sequence groups of all detection positions of the living tissue before the action of the acoustic radiation force and all second complex signal sequence groups after the action;
s4, constructing a structural image of the living tissue, an elastic image of the living tissue and a plurality of image combinations in a blood flow image of the living tissue according to the first complex signal sequence group and/or the second complex signal sequence group corresponding to all detection positions; determining vibration data of the detection position changing with depth at different time points according to a second complex signal sequence corresponding to the same detection position at different time points; determining vibration distribution images of the living tissue at different time points according to vibration data of all detection positions changing with depth at different time points; and constructing an elastic image of the living tissue according to vibration distribution images of the living tissue at different time points.
2. The optical coherence tomography of living tissue according to claim 1, wherein constructing a combination of a plurality of images among a structural image of the living tissue, an elastic image of the living tissue, and a blood flow image of the living tissue from the first plurality of signal sequence sets and/or the second plurality of signal sequence sets corresponding to all detection positions comprises:
and constructing a plurality of image combinations in the structural image of the living tissue, the elastic image of the living tissue and the blood flow image of the living tissue according to the first complex signal sequence group corresponding to the first preset time period before the radiation force is acted on and/or the second complex signal sequence group corresponding to the second preset time period after the radiation force is acted on.
3. The optical coherence tomography multi-modality imaging method of a living tissue according to claim 1, wherein a structural image of the living tissue at the same time point is constructed from a first complex signal sequence corresponding to all detection positions at the same time point or from a second complex signal sequence corresponding to all detection positions at the same time point;
and/or constructing structural images of the living tissue at different time points according to the first complex signal sequences corresponding to all detection positions at different time points or according to the second complex signal sequences corresponding to all detection positions at different time points.
4. The method of claim 3, wherein determining structural data of the probe location as a function of depth at any point in time based on any one of the first complex signal sequence and the second complex signal sequence corresponding to the probe location comprises:
and determining structural data of the detection position changing with depth at any time point according to the amplitude of the complex signals in the complex signal sequence, wherein the structural data of the detection position changing with depth at any time point is used for constructing a structural image of the living tissue according to the structural data corresponding to all the detection positions.
5. The method of claim 1, wherein the blood flow data of the detection position changing with depth at different time points is determined from a first complex signal sequence corresponding to the same detection position at different time points; and constructing blood flow images of the living tissue at different time points according to the blood flow data of all the detection positions which change with depth at different time points.
6. The method of claim 5, wherein determining blood flow data for the probe location as a function of depth at any point in time based on a corresponding first plurality of signal sequences for the probe location comprises:
And determining blood flow data of the detection position changing with depth at any time point according to the amplitude and/or the phase of the complex signals in the first complex signal sequence of the detection position at any time point.
7. The method of claim 1, wherein determining vibration data of the probe location as a function of depth at any point in time based on a corresponding second plurality of signal sequences of the probe location comprises:
and determining vibration data of the detection position changing with depth at any time point according to the amplitude and/or the phase of the complex signals in the second complex signal sequence of the detection position at any time point.
8. The optical coherence tomography multi-modality imaging method of a living tissue according to claim 1, wherein constructing an elasticity image of the living tissue from vibration distribution images of the living tissue at different time points comprises:
calculating elastic data of the living tissue according to vibration distribution images of the living tissue at different time points, wherein the elastic data comprises at least one of maximum amplitude, resonant frequency and elastic wave speed of the living tissue at different spatial positions;
And constructing an elastic image of the living tissue according to the elastic data.
9. An optical coherence tomography multi-modality imaging apparatus of living tissue, comprising: an optical coherence tomography unit and an acoustic radiation force excitation unit;
the acoustic radiation force excitation unit is used for generating an acoustic radiation force to act on a fixed receiving position of the living tissue;
the optical coherence tomography unit is used for dividing weak coherent light beams with different wavelengths in a preset wave band into a reference beam and a detection beam before the acoustic radiation force acts on a fixed receiving position of the living tissue, controlling the detection position of the detection beam irradiated on the surface of the living tissue to generate a feedback beam, controlling the reference beam to be irradiated on a reflecting mirror to generate a reflecting beam, controlling the feedback beam and the reflecting beam to interfere to generate an interference beam, extracting an interference signal sequence corresponding to the interference beam and changing along with the wavelength, and performing Fourier transformation to obtain a first complex signal sequence of the detection position along with the depth, thereby obtaining a first complex signal sequence group comprising a plurality of first complex signal sequences corresponding to a plurality of time points and changing along with the depth; and obtaining a set of detection positions in the above manner after the acoustic radiation force acts on the fixed receiving position of the living tissue, the set of detection positions comprising a plurality of second plurality of signal sequences corresponding to a plurality of time points that vary with depth after the acoustic radiation force acts on the plurality of second plurality of signal sequences; repeating the above process until the scanning of all detection positions of the detection light beam on the surface of the living tissue is completed, and obtaining all first complex signal sequence groups of all detection positions of the living tissue before the action of the acoustic radiation force and all second complex signal sequence groups after the action; constructing a structural image of the living tissue, an elastic image of the living tissue and a plurality of image combinations in a blood flow image of the living tissue according to the first complex signal sequence group and/or the second complex signal sequence group corresponding to all detection positions; determining vibration data of the detection position changing with depth at different time points according to a second complex signal sequence corresponding to the same detection position at different time points; determining vibration distribution images of the living tissue at different time points according to vibration data of all detection positions changing with depth at different time points; and constructing an elastic image of the living tissue according to vibration distribution images of the living tissue at different time points.
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Publication number Priority date Publication date Assignee Title
CN112348907B (en) * 2020-10-16 2024-03-26 佛山科学技术学院 Compression method and device for optical coherence tomography three-dimensional data
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108778107A (en) * 2016-03-04 2018-11-09 皇家飞利浦有限公司 Device for vascular characterization
CN110693457A (en) * 2019-10-14 2020-01-17 浙江大学 Tissue activity detection method and system based on optical coherence technology
CN110974148A (en) * 2019-12-03 2020-04-10 温州医科大学 Method for measuring cornea elastic modulus of in-vivo human eye based on jet optical coherence elastography technology
CN111000532A (en) * 2019-07-16 2020-04-14 南昌航空大学 Oral cavity soft tissue detection device and method based on optical Doppler imaging

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5192846B2 (en) * 2008-02-25 2013-05-08 オリンパスメディカルシステムズ株式会社 Biological observation apparatus and method of operating biological observation apparatus
US20150011895A1 (en) * 2012-03-28 2015-01-08 University Of Washington Through Its Center For Commercialization Methods and Systems for Determining Mechanical Properties of a Tissue
US20150371401A1 (en) * 2013-03-13 2015-12-24 University Of Washington Methods and Systems for Imaging Tissue Motion Using Optical Coherence Tomography
US10548479B2 (en) * 2015-02-16 2020-02-04 The Regents Of The University Of California Optical coherence elastography (OCE) method under acoustic radiation force excitation using OCT doppler variance methods and OCT correlation-based methods
CN106963338B (en) * 2017-03-31 2018-09-07 杭州电子科技大学 Crystalline lens biomethanics and the noninvasive imaging in vivo system of optical characteristics and measurement method
CN109907731B (en) * 2019-01-31 2021-06-01 浙江大学 Three-dimensional blood flow radiography method based on optical coherence tomography of feature space

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108778107A (en) * 2016-03-04 2018-11-09 皇家飞利浦有限公司 Device for vascular characterization
CN111000532A (en) * 2019-07-16 2020-04-14 南昌航空大学 Oral cavity soft tissue detection device and method based on optical Doppler imaging
CN110693457A (en) * 2019-10-14 2020-01-17 浙江大学 Tissue activity detection method and system based on optical coherence technology
CN110974148A (en) * 2019-12-03 2020-04-10 温州医科大学 Method for measuring cornea elastic modulus of in-vivo human eye based on jet optical coherence elastography technology

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
正向切片光学相干断层成像系统的信号提取方法;杨强等;《光学学报》;全文 *
面向血管内脂质斑块检测的超声-OCT成像系统;徐勇;汪毅;邱建榕;沈毅;肖禹泽;陈晓冬;;激光与光电子学进展(第08期);全文 *

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