Optical coherence elastography method, device, electronic equipment and storage medium

Abstract

The present application relates to the technical field of imaging, in particular to an optical coherence elastography method and device, electronic equipment and storage medium, wherein the method comprises: outputting laser light meeting preset time periodicity conditions and preset linear variation conditions by using a sweep frequency light source; generating a driving signal containing an analog signal or a digital signal according to a trigger signal; scanning a sample according to the driving signal; applying mechanical excitation to the sample by using the driving signal, generating two-dimensional imaging and three-dimensional imaging of the sample according to two-dimensional elastic waves and three-dimensional elastic waves respectively; interfering laser light reflected by a sample arm with reference arm laser light; reconstructing the interference signal into a sample structure image, generating biomechanical information of the sample according to the elastic waves, and determining the final optical coherence elastography result according to the biomechanical information, the three-dimensional imaging and the two-dimensional imaging. Thus, the problem that the existing optical coherence elastography method cannot realize two-dimensional dynamic imaging and three-dimensional in vivo imaging is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of imaging technology, in particular to an optical coherence elastography method and device, an electronic device and a storage medium. BACKGROUND

[0002] Elastography method: the mechanical properties of human tissues can reflect the health status of the human body. Many diseases, such as liver fibrosis, arteriosclerosis, cancer, etc., will cause changes in the mechanical properties of human tissues. By measuring the mechanical properties of human tissues, some diseases can be diagnosed. In ancient times, people used palpation to diagnose some diseases. With the development of science and technology, people hope to non-invasively and non-destructively characterize the mechanical properties of tissues on the body. In the past 30 years, a series of methods for in-vivo characterization of soft tissue mechanical properties have been developed, collectively known as elastography methods (because the measurement results are often represented as [soft and hard distribution images], so they are called elastography methods). Typical elastography methods include: shear wave ultrasound elastography, magnetic resonance elastography method, etc. These elastography methods have strong adaptability and wide application range, but the device cost is too high, which is not suitable for use in specialized application scenarios.

[0003] Optical coherence elastography technology. Studies have shown that many diseases (such as liver fibrosis, tumors, and vascular plaques) will change the mechanical properties of the corresponding tissues of the human body. Therefore, in-vivo measurement of the mechanical properties of soft tissues is of great significance for the diagnosis (especially early diagnosis) of many diseases. Elastography is a type of technology developed based on the above background, and has obtained preliminary application in the fields of liver fibrosis diagnosis and breast nodule classification. The OCE (Optical coherence elastography) method is an elastography technology developed based on OCT (Optical coherence tomography). The basic principle of OCE technology is to use a certain mechanical excitation to produce static or dynamic deformation in soft tissue, measure the deformation by OCT technology, and then use the measured deformation to invert the biomechanical properties of soft tissue. The OCE technology based on static deformation has been preliminarily applied to the problem of intraoperative judgment of tumor tissue boundary. The limitation of the OCE technology based on static deformation is that it can only qualitatively measure the elastic modulus of soft tissue. The OCE technology based on dynamic deformation (shear wave) can quantitatively give the biomechanical properties of soft tissue and has a wide range of applications.

[0004] OCE measurement of the cornea has important clinical applications. The cornea is a transparent biological soft tissue with a thickness of about 0.5 mm. The cornea provides about 2 / 3 of the refractive power of the eye's optical system, so a stable corneal shape is an important guarantee for maintaining normal vision. Under the action of intraocular pressure, the cornea is shaped like a crescent moon. When the center of the cornea degenerates, its shape may become conical, which seriously affects vision. The continuously developing keratoconus disease may eventually lead patients to need to perform corneal transplantation. On the other hand, laser surgery has become an important method for correcting myopia. By laser cutting of the cornea, its refractive power is weakened, which can achieve the purpose of correcting myopia. In the preoperative planning of laser surgery, accurate knowledge of the biomechanical properties of the cornea can help accurately calculate the deformation of the cornea after cutting and better assess the safety and accuracy of myopia laser surgery.

[0005] In the related art, in a non-invasive acoustic testing method and device for soft tissue elasticity, the device generates tangential vibration deformation on the surface of the measured tissue, picks up the surface vibration through a piezoelectric transducer, analyzes the vibration signal, and measures the anisotropy of the tissue; in a method for estimating the elasticity of a soft elastic solid from surface wave measurements, the device is composed of an excitation vibrator and a plurality of vibration sensors (piezoelectric sensors), thereby measuring the surface wave velocity / dispersion properties and obtaining the mechanical properties of the material; in a method and device for estimating the elasticity of a soft solid by measuring surface waves, the device is composed of an external vibration source and a vibration sensor array. SUMMARY

[0006] The present application provides an optical coherence elastography method, device, electronic equipment and storage medium, to solve the main limitation of the existing optical coherence elastography method is slow imaging speed. Specifically, optical coherence elastography adopts M-B scanning mode, generally speaking, the time required for two-dimensional imaging is seconds. Therefore, this method cannot be used for dynamic biological tissues. At the same time, the time required for three-dimensional imaging is about minutes, and this imaging speed cannot be used for in vivo measurement and the like.

[0007] The first aspect of the present application provides an optical coherence elastography method, comprising the following steps: outputting laser light meeting preset time periodicity conditions and preset linear variation conditions by using a frequency-sweeping light source; receiving a trigger signal of the frequency-sweeping light source by using a waveform generating card, and generating a driving signal containing an analog signal or a digital signal according to the trigger signal; scanning a sample according to the driving signal, and generating a scanning result; based on the scanning result, applying mechanical excitation to the sample by using the driving signal to generate two-dimensional elastic waves and three-dimensional elastic waves in the sample, and generating two-dimensional imaging and three-dimensional imaging of the sample according to the two-dimensional elastic waves and the three-dimensional elastic waves respectively; dividing the laser light into reference arm laser light and sample arm laser light by using a coherent light path, and interfering the sample arm laser light after reflection with the reference arm laser light to generate an interference signal; reconstructing the interference signal into a sample structure image, and extracting elastic waves in the sample based on the sample structure image to generate biomechanical information of the sample according to the elastic waves, and determining a final optical coherence elastography result according to the biomechanical information, the three-dimensional imaging and the two-dimensional imaging.

[0008] Optionally, in an embodiment of the present application, after the sample arm laser light is reflected and interfered with the reference arm laser light to generate an interference signal, the method further comprises: measuring the interference signal and converting the interference signal into an analog signal of the sample; or, storing the interference signal to generate a digital signal of the sample.

[0009] Optionally, in an embodiment of the present application, the step of applying mechanical excitation to the sample by using the driving signal to generate two-dimensional elastic waves and three-dimensional elastic waves in the sample, and generating two-dimensional imaging and three-dimensional imaging of the sample according to the two-dimensional elastic waves and the three-dimensional elastic waves respectively, comprises: determining an imaging sequence of the sample with the frequency of the frequency-sweeping light source as a clock, and receiving a sine signal of the waveform generating card based on the imaging sequence; applying excitation to the sample by using the sine signal to implement a target scanning mode along a second direction axis under the condition that the sample remains stationary in a first direction axis; and cyclically executing the target scanning mode three times until three-dimensional scanning of the sample meets a preset ending condition, generating three-dimensional elastic waves of the sample, and determining three-dimensional imaging of the sample according to the three-dimensional elastic waves.

[0010] Optionally, in an embodiment of the present application, the target scanning mode corresponds to interference signals respectively as follows:

[0011]

[0012]

[0013]

[0014] wherein, is the interference signal corresponding to the first scan, is the interference signal corresponding to the second scan, is the interference signal corresponding to the third scan, is the static interference signal of the pixel point, and , and respectively represent the amplitude and phase of the left and right fluctuations of the pixel point;

[0015] The static interference signal of the pixel point is obtained by averaging the interference signals of the three scans:

[0016]

[0017] wherein, is the static interference signal of the pixel point, is the interference signal corresponding to the first scan, is the interference signal corresponding to the second scan, is the interference signal corresponding to the third scan;

[0018] The amplitude and phase of the left and right fluctuations of the pixel point are respectively:

[0019]

[0020]

[0021] wherein, and are the fluctuation signals obtained by removing the static signal from the first two scan signals, is the amplitude of the right fluctuation of the pixel point, is the amplitude of the left fluctuation of the pixel point;

[0022] The fluctuation signals obtained by removing the static signal from the first two scan signals are:

[0023]

[0024]

[0025] wherein, is the interference signal corresponding to the first scan, is the interference signal corresponding to the second scan, is the static interference signal of the pixel point, and , and respectively represent the amplitude and phase of the fluctuation on the left and right sides of the pixel point.

[0026] Optionally, in an embodiment of the present application, the method further comprises: based on the frequency of the frequency-sweeping laser and the piezoelectric effect of the preset excitation system, driving the contact probe to transmit vibration to the sample to generate two-dimensional elastic waves in the sample, and determining two-dimensional imaging of the sample based on the two-dimensional elastic waves.

[0027] In a second aspect, an embodiment of the present application provides an optical coherence elastography device, comprising: an output module configured to output laser light that satisfies preset time periodicity conditions and preset linear variation conditions by using a frequency-sweeping light source; a receiving module configured to receive a trigger signal of the frequency-sweeping light source by using a waveform generator card, and generate a driving signal containing an analog signal or a digital signal according to the trigger signal; a scanning module configured to scan a sample according to the driving signal to generate a scanning result; a generating module configured to apply mechanical excitation to the sample by using the driving signal to generate two-dimensional elastic waves and three-dimensional elastic waves in the sample based on the scanning result, and generate two-dimensional imaging and three-dimensional imaging of the sample based on the two-dimensional elastic waves and the three-dimensional elastic waves, respectively; an interference module configured to divide the laser light into reference arm laser light and sample arm laser light by using a coherent light path, and interfere the sample arm laser light after reflection with the reference arm laser light to generate an interference signal; and an imaging module configured to reconstruct the interference signal into a sample structure image, extract elastic waves in the sample based on the sample structure image, generate biomechanical information of the sample according to the elastic waves, and determine a final optical coherence elastography result according to the biomechanical information, the three-dimensional imaging, and the two-dimensional imaging.

[0028] Optionally, in an embodiment of the present application, the device further comprises: a measuring module configured to measure the interference signal after the sample arm laser light after reflection is interfered with the reference arm laser light to generate an interference signal, and convert the interference signal into an analog signal of the sample; or a storage module configured to store the interference signal to generate a digital signal of the sample.

[0029] Optionally, in an embodiment of the present application, the generating module comprises: a determining unit configured to determine an imaging sequence of the sample with the frequency of the frequency-sweeping light source as a clock, and receive a sinusoidal signal of the waveform generating card based on the imaging sequence; an implementing unit configured to apply an excitation to the sample by using the sinusoidal signal, so as to implement a target scanning mode along a direction of a second direction axis while keeping still in a direction of a first direction axis; and a generating unit configured to cyclically execute the target scanning mode three times until a three-dimensional scanning of the sample meets a preset ending condition, generate a three-dimensional elastic wave of the sample, and determine a three-dimensional imaging of the sample according to the three-dimensional elastic wave.

[0030] Optionally, in an embodiment of the present application, the target scanning mode corresponds to the following interference signals respectively:

[0031]

[0032]

[0033]

[0034] wherein, is the interference signal corresponding to the first scanning, is the interference signal corresponding to the second scanning, is the interference signal corresponding to the third scanning, is a static interference signal of the pixel point, and , and respectively represent the amplitude and phase of the left and right fluctuations of the pixel point;

[0035] The static interference signal of the pixel point is obtained by averaging the interference signals of the three scans:

[0036]

[0037] wherein, is the static interference signal of the pixel point, is the interference signal corresponding to the first scanning, is the interference signal corresponding to the second scanning, is the interference signal corresponding to the third scanning;

[0038] The amplitude and phase of the left and right fluctuations of the pixel point are respectively:

[0039]

[0040]

[0041] wherein, and is the fluctuation signal obtained by removing static signals from the first two scanning signals, is the amplitude of the fluctuation on the right side of the pixel point, is the amplitude of the fluctuation on the left side of the pixel point;

[0042] The fluctuation signal obtained by removing static signals from the first two scanning signals is:

[0043]

[0044]

[0045] wherein, is the interference signal corresponding to the first scanning, is the interference signal corresponding to the second scanning, is the static interference signal of the pixel point, and , and respectively represent the amplitude and phase of the fluctuation on the left and right sides of the pixel point.

[0046] Optionally, in an embodiment of the present application, the generating module further comprises a transmission unit configured to drive the contact probe to transmit vibration to the sample to generate a two-dimensional elastic wave of the sample based on the frequency of the frequency-sweeping laser and the piezoelectric effect of the preset excitation system, and determine a two-dimensional image of the sample according to the two-dimensional elastic wave.

[0047] The third aspect of the present application provides an electronic device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the optical coherence elastography method as described in the above embodiments.

[0048] The fourth aspect of the present application provides a computer readable storage medium, which stores a computer program, wherein the program is executed by a processor to implement the optical coherence elastography method as described above.

[0049] The fifth aspect of the present application provides a computer program product, which stores a computer program, wherein the program is executed by a processor to implement the optical coherence elastography method as described above.

[0050] The embodiment of the present application can improve the existing imaging speed by hundreds of times, realizes two-dimensional millisecond imaging speed, and can realize two-dimensional dynamic imaging; three-dimensional imaging speed is less than 1 second, and can realize living body and three-dimensional optical coherence elastography. Thus, the limitation of the existing optical coherence elastography is broken: unable to realize two-dimensional dynamic imaging and unable to realize three-dimensional living body imaging.

[0051] Additional aspects and advantages of the present application will be made apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0052] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the accompanying drawings, in which:

[0053] Figure 1 A flow chart of an optical coherence elastography method according to an embodiment of the present application is provided;

[0054] Figure 2 A hardware system configuration diagram according to an embodiment of the present application is provided;

[0055] Figure 3 A system imaging sequence diagram according to an embodiment of the present application is provided;

[0056] Figure 4 A three-dimensional imaging diagram according to an embodiment of the present application is provided;

[0057] Figure 5 A PZT-based excitation system design diagram according to an embodiment of the present application is provided;

[0058] Figure 6 A two-dimensional imaging diagram according to an embodiment of the present application is provided;

[0059] Figure 7 A dynamic imaging diagram according to an embodiment of the present application is provided;

[0060] Figure 8 A coherent light path diagram according to an embodiment of the present application is provided;

[0061] Figure 9 A structure diagram of an optical coherence elastography device according to an embodiment of the present application is provided;

[0062] Figure 10 A structure diagram of an electronic device according to an embodiment of the present application is provided.

[0063] 10 - optical coherence elastography device; 100 - output module, 200 - receiving module, 300 - scanning module, 400 - generating module, 500 - interference module, 600 - imaging module; 901 - memory, 902 - processor, 903 - communication interface. DETAILED DESCRIPTION

[0064] Embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar reference numbers represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0065] The optical coherence elastography method, device, electronic equipment and storage medium of the embodiments of the present application are described below with reference to the drawings. The main limitation of the existing optical coherence elastography method mentioned in the above background art is slow imaging speed. Specifically, optical coherence elastography uses M-B scanning mode, generally, the time required for two-dimensional imaging is seconds. Therefore, this method cannot be used for dynamic biological tissues. At the same time, the time required for three-dimensional imaging is about minutes, and this imaging speed cannot be implemented on a living body. The present application provides an optical coherence elastography method, in which the imaging speed can be increased by about 300 times, the two-dimensional imaging time can be reduced from seconds to milliseconds, and dynamic two-dimensional imaging can be achieved; the three-dimensional imaging time can be reduced to within 1 second, and three-dimensional living body imaging can be achieved. Through innovative imaging sequence design and imaging algorithm, efficient collaborative operation of the laser and the scanning galvanometer and the excitation module is realized. Thus, the main limitation of the existing optical coherence elastography method, i.e. slow imaging speed, is solved. Specifically, optical coherence elastography uses M-B scanning mode, generally, the time required for two-dimensional imaging is seconds. Therefore, this method cannot be used for dynamic biological tissues. At the same time, the time required for three-dimensional imaging is about minutes, and this imaging speed cannot be implemented on a living body, and other problems are solved.

[0066] Specifically, Figure 1 A flowchart of an optical coherence elastography method provided by the embodiments of the present application is shown in FIG. 1.

[0067] As Figure 1 shown, the optical coherence elastography method includes the following steps:

[0068] In step S101, a laser outputting a laser satisfying a preset time periodicity condition and a preset linear variation condition is used.

[0069] In the actual execution process, as Figure 2As shown, the embodiment of the present application can utilize the laser with the periodically time-varying and linearly varying output wavelength to scan the frequency of the laser. During the periodic scanning of the laser, the trigger model is sent to the waveform generating card to synchronize the waveform generating card with the frequency-sweeping light source.

[0070] It should be noted that the preset time-varying condition and the preset linearly varying condition can be set by the person skilled in the art according to the actual situation, and are not specifically limited herein.

[0071] In step S102, the trigger signal of the frequency-sweeping light source is received by the waveform generating card, and the driving signal containing the analog signal or the digital signal is generated according to the trigger signal.

[0072] In the embodiment of the present application, the trigger signal of the frequency-sweeping light source is received by the waveform generating card, and the analog / digital signal is generated synchronously to drive the scanning galvanometer and the excitation module.

[0073] In step S103, the sample is scanned according to the driving signal to generate the scanning result.

[0074] In the actual execution process, the driving signal of the waveform generating card is received by the scanning galvanometer, the X and Y axis scanning is implemented by the motor driving two plane mirrors, the scanning result is generated, and the three-dimensional imaging is realized.

[0075] In step S104, based on the scanning result, the mechanical excitation is applied to the sample by the driving signal to generate the two-dimensional elastic wave and the three-dimensional elastic wave in the sample, and the two-dimensional imaging and the three-dimensional imaging of the sample are generated according to the two-dimensional elastic wave and the three-dimensional elastic wave respectively.

[0076] As a possible implementation, the embodiment of the present application can apply the mechanical excitation to the sample by the driving signal based on the scanning result to generate the two-dimensional elastic wave and the three-dimensional elastic wave in the sample, and generate the two-dimensional imaging and the three-dimensional imaging of the sample according to the two-dimensional elastic wave and the three-dimensional elastic wave respectively, wherein the excitation module used by the present application contains the power amplification module and the actuator module. The driving signal of the waveform generating card is received, and the driving signal is amplified by the power amplification module to drive the actuator module to generate the mechanical signal. The mechanical signal acts on the sample and excites the elastic wave in the sample. The design of the actuator module has multiple types. In one embodiment, the piezoelectric driver is used as the actuator module. In another embodiment, the ultrasonic transducer is used as the actuator module.

[0077] Optionally, in one embodiment of the present application, a mechanical excitation is applied to the sample by using a driving signal to generate two-dimensional elastic waves and three-dimensional elastic waves in the sample, and two-dimensional imaging and three-dimensional imaging of the sample are generated according to the two-dimensional elastic waves and the three-dimensional elastic waves, comprising: determining an imaging sequence of the sample with a frequency of a frequency-sweeping light source as a clock, and receiving a sine signal of a waveform generating card based on the imaging sequence; applying excitation to the sample by using the sine signal to implement a target scanning mode in a direction of a second direction axis while keeping still in a direction of a first direction axis; and performing the target scanning mode cyclically three times until a three-dimensional scanning of the sample meets a preset ending condition, generating three-dimensional elastic waves of the sample, and determining three-dimensional imaging of the sample according to the three-dimensional elastic waves.

[0078] It can be understood that the first direction axis in the embodiment of the present application can be a Y axis, and the second direction axis can be an X axis.

[0079] As shown in the imaging sequence of the embodiment of the present application, Figure 3 the Y axis is Y-axis, the X axis is X-axis, and the whole imaging sequence takes Aline shown in the frequency (fa) of the frequency-sweeping light source as a clock, Figure 3 the excitation module receives the sine signal of the waveform generating card to apply excitation to the sample. At the same time, the galvanometer corresponding to the Y axis direction keeps still, and the X axis direction starts a B scanning mode. The scanning is divided into three times, which are respectively referred to as B11, B12 and B13. As shown in Figure 3 the phases of the sine signals of the corresponding excitation modules are 0, 2π / 3 and 4π / 3 respectively when the three B scans start. The three B modes contain the same number of Aline, but the number of Aline contained is Nx. Nx can be arbitrary. After the above-mentioned three B scans are completed, the Y axis is adjusted by an angle, and the above-mentioned B scanning mode is repeated in the X axis direction to obtain B21, B22 and B23. Similarly, the above-mentioned process is repeated, when the Y axis is scanned for the i th time, the X axis is scanned for three times to obtain three B mode scans Bi1, Bi2 and Bi3. The Y axis direction is scanned for Ny times according to needs. Similarly, Ny can be arbitrary. The above-mentioned one three-dimensional scanning contains 3*Nx*Ny Aline in total, and the total time length is 3*Nx*Ny / fa.

[0080] For example, in one three-dimensional embodiment, a PZT (piezoelectric crystal sensor) excitation system is adopted, the excitation frequency is 3 kHz, Nx = 200, and Ny = 100. Thus, the total time of one measurement is: 200 × 100 × 3 × (1 / 100e3) = 0.6 seconds. Figure 4 As shown in the elastic wave field obtained by measurement. The three cloud maps respectively show the elastic waves in the x-y, y-z and x-z cross sections.

[0081] The traditional optical coherence elastography adopts an M-B scanning mode, and when three-dimensional scanning is performed, the total Aline quantity required is about 900*Nx*Ny.

[0082] The embodiment of the present application proposes a new imaging sequence, and full-field elastic waves can be obtained by three continuous B mode scanning.

[0083] Optionally, in an embodiment of the present application, the interference signals corresponding to the target scanning mode are respectively:

[0084]

[0085]

[0086]

[0087] wherein, is the interference signal corresponding to the first scanning, is the interference signal corresponding to the second scanning, is the interference signal corresponding to the third scanning, is the static interference signal of the pixel point, and , and respectively represent the amplitude and phase of the left and right fluctuations of the pixel point;

[0088] The static interference signal of the pixel point is obtained by averaging the interference signals of the three scans:

[0089]

[0090] wherein, is the static interference signal of the pixel point, is the interference signal corresponding to the first scanning, is the interference signal corresponding to the second scanning, is the interference signal corresponding to the third scanning;

[0091] The amplitude and phase of the left and right fluctuations of the pixel point are respectively:

[0092]

[0093]

[0094] wherein, and is the fluctuation signal obtained by removing the static signal from the first two scanning signals, is the amplitude of the fluctuation on the right side of the pixel point, is the amplitude of the fluctuation on the left side of the pixel point;

[0095] The fluctuation signal obtained by removing the static signal from the first two scanning signals is:

[0096]

[0097]

[0098] wherein, is the interference signal corresponding to the first scanning, is the interference signal corresponding to the second scanning, is the static interference signal of the pixel point, and , and respectively represent the amplitude and phase of the fluctuation on the left and right sides of the pixel point.

[0099] Specifically, the embodiment of the present application proposes a new imaging algorithm. The method uses three times of B-mode scanning synchronized with excitation, i.e. Bi1, Bi2 and Bi3, to calculate the amplitude and phase of the elastic wave. The specific method is as follows:

[0100] 1) For any pixel point, the interference signal of the sample light and the reference light is wherein, is the static interference signal of the pixel point.

[0101] 2) The phases of the excitation corresponding to the three times of B-mode scanning are respectively different by 2 π / 3, and the corresponding interference signals are:

[0102]

[0103]

[0104]

[0105] 3) The static interference signal of the pixel point can be obtained by averaging the interference signals of the three times of scanning:

[0106]

[0107] 4) Calculate:

[0108] and .

[0109] 5) The amplitude and phase of the fluctuations on the left and right sides of the pixel can be determined by... and The solution yields:

[0110]

[0111]

[0112] Optionally, in one embodiment of the present invention, a mechanical excitation is applied to the sample using a driving signal to generate two-dimensional elastic waves and three-dimensional elastic waves in the sample, and two-dimensional and three-dimensional images of the sample are generated based on the two-dimensional elastic waves and three-dimensional elastic waves, respectively. The method further includes: driving a contact probe to transmit vibration to the sample based on the frequency of a swept laser and the piezoelectric effect of a preset excitation system to generate two-dimensional elastic waves of the sample, and determining two-dimensional images of the sample based on the two-dimensional elastic waves.

[0113] It is understandable that the preset incentive system can be the PZT incentive system.

[0114] Taking two-dimensional imaging as an example, the imaging time required by the method of this invention is approximately 6 milliseconds, while the traditional method requires approximately 2000 milliseconds, representing an improvement in imaging speed of approximately 300 times. Therefore, the method of this invention can achieve two-dimensional dynamic imaging. Using the method of this invention, the three-dimensional imaging time is less than 1 second, enabling live-body, three-dimensional imaging.

[0115] In a two-dimensional imaging example, a hydrogel sample is used as the imaging object, and the following is utilized: Figure 5 The excitation system shown is a swept laser with a frequency of fa = 100 kHz. The excitation system is based on the piezoelectric effect of PZT, which drives a contact probe to transmit vibrations to the sample. This excitation system is suitable for exciting elastic waves from 100 Hz to 100 kHz. In this specific embodiment, the excitation frequency is chosen to be 3 kHz.

[0116] Figure 6 In the figure, A represents the two-dimensional elastic wave measured by the method of this invention, where Nx = 200. The time required for one imaging session is approximately 200 × 3 × (1 / 100e3) = 6 milliseconds. In comparison, using the existing MB mode, each M scan uses 1000 Alines, Nx = 200, and the total time is approximately 200 × 1000 × (1 / 100e3) = 2000 milliseconds. The wave image obtained using the MB mode is shown below. Figure 6 As shown in B.

[0117] Further, in one embodiment of dynamic imaging, the present application can measure the tension wave velocity in a plastic film. By dynamically changing the tension in the film, the velocity in the film is dynamically changed. In this embodiment, the velocity in the film can be continuously measured. As shown in FIG. 6, the tension in the film is changed within 5 seconds, while the two-dimensional ultrafast imaging method is used to continuously measure the tension in the film. It can be seen that the method described in the present application can dynamically and continuously measure the imaging. In contrast, the conventional M-B scanning mode needs 2 seconds for each measurement, and cannot measure the dynamic change process described above. Figure 7

[0118] In step S105, the laser is divided into reference arm laser and sample arm laser by a coherent light path, and the sample arm laser is reflected and interfered with the reference arm laser to generate an interference signal.

[0119] In actual implementation, the embodiment of the present application can use a Michelson coherent light path to divide the received laser into two paths of reference arm and sample arm. The laser in the sample arm is reflected via the sample and interfered with the laser of the reference arm. The coherent light path is shown in FIG. 1. Figure 8

[0120] Optionally, in one embodiment of the present application, after the sample arm laser is reflected and interfered with the reference arm laser to generate an interference signal, it further includes: measuring the interference signal and converting the interference signal into an analog signal of the sample; or, storing the interference signal to generate a digital signal of the sample.

[0121] Specifically, the high-speed data acquisition system in the embodiment of the present application is composed of a photodetector module and a high-speed data acquisition card module. The photodetector measures the interference signal and converts it into an analog signal. The high-speed acquisition card stores the interference signal as a digital signal through A / D conversion.

[0122] In step S106, the interference signal is reconstructed into a sample structure image, and the elastic wave in the sample is extracted based on the sample structure image to generate the biomechanical information of the sample according to the elastic wave, and the final optical coherence elastography result is determined according to the biomechanical information, three-dimensional imaging and two-dimensional imaging.

[0123] In actual implementation, the embodiment of the present application can use a post-processing and display system: the collected interference signal is reconstructed into a sample structure image by a post-processing algorithm. At the same time, the sample elastic wave information is extracted, and the sample biomechanical information (such as elasticity, viscoelasticity, anisotropy, etc.) is obtained by post-processing the elastic wave information, and the final optical coherence elastography result is determined according to the biomechanical information, three-dimensional imaging and two-dimensional imaging. The structure image and the biomechanical information are displayed or printed in the form of a report and a chart.

[0124] ​​The embodiment of the present application greatly improves the speed of the existing optical coherence elastography, and increases the speed of the optical coherence elastography by about 300 times, and can realize dynamic two-dimensional imaging, three-dimensional imaging and the like.

[0125] The optical coherence elastography method according to the embodiment of the present application can increase the imaging speed by about 300 times, reduce the two-dimensional imaging time from the order of seconds to milliseconds, and realize dynamic two-dimensional imaging; the three-dimensional imaging time is reduced to within 1 second, and three-dimensional in-vivo imaging can be realized. Through the innovative imaging sequence design and imaging algorithm, the efficient collaborative operation of the laser, the scanning galvanometer and the excitation module is realized. Thus, the main limitation of the existing optical coherence elastography method, i.e., slow imaging speed, is solved. Specifically, the optical coherence elastography adopts the M-B scanning mode, and generally, the two-dimensional imaging time is in the order of seconds. Therefore, this method cannot be used for dynamic biological tissues. Meanwhile, the three-dimensional imaging time is about minutes, and this imaging speed cannot be used for in-vivo measurement.

[0126] Secondly, the optical coherence elastography device according to the embodiment of the present application is described with reference to the accompanying drawings.

[0127] Figure 9 is a structural schematic diagram of the optical coherence elastography device according to the embodiment of the present application.

[0128] As shown in Figure 9 , the optical coherence elastography device 10 comprises an output module 100, a receiving module 200, a scanning module 300, a generating module 400, an interference module 500 and an imaging module 600.

[0129] Specifically, the output module 100 is configured to output laser satisfying preset time periodicity conditions and preset linear variation conditions by using a frequency-sweeping light source.

[0130] The receiving module 200 is configured to receive a trigger signal of the frequency-sweeping light source by using a waveform generating card, and generate a driving signal containing an analog signal or a digital signal according to the trigger signal.

[0131] The scanning module 300 is configured to scan a sample according to the driving signal, and generate a scanning result.

[0132] The generating module 400 is configured to apply mechanical excitation to the sample by using the driving signal based on the scanning result, so as to generate two-dimensional elastic waves and three-dimensional elastic waves in the sample, and generate two-dimensional imaging and three-dimensional imaging of the sample according to the two-dimensional elastic waves and the three-dimensional elastic waves, respectively.

[0133] The interference module 500 is configured to divide the laser into reference arm laser and sample arm laser by using a coherent light path, and interfere the sample arm laser after reflection with the reference arm laser, so as to generate an interference signal.

[0134] The imaging module 600 is configured to reconstruct the interference signal into a sample structure image, and extract an elastic wave in the sample based on the sample structure image, so as to generate biomechanical information of the sample according to the elastic wave, and determine a final optical coherence elastography result according to the biomechanical information, the three-dimensional imaging and the two-dimensional imaging.

[0135] Optionally, in an embodiment of the present application, the optical coherence elastography device 10 further comprises a measurement module or a storage module.

[0136] The measurement module is configured to measure the interference signal after the interference between the sample arm laser reflection and the reference arm laser is generated, and convert the interference signal into an analog signal of the sample.

[0137] The storage module is configured to store the interference signal to generate a digital signal of the sample.

[0138] Optionally, in an embodiment of the present application, the generating module 400 comprises a determining unit, an implementing unit and a generating unit.

[0139] The determining unit is configured to determine an imaging sequence of the sample with the frequency of the swept source as a clock, and receive a sine signal of the waveform generator card based on the imaging sequence.

[0140] The implementing unit is configured to apply an excitation to the sample by using the sine signal, so as to implement a target scanning mode along a second direction axis under the condition that the sample remains stationary in a first direction axis.

[0141] The generating unit is configured to cyclically execute the target scanning mode three times until a three-dimensional scanning of the sample meets a preset ending condition, generate a three-dimensional elastic wave of the sample, and determine a three-dimensional imaging of the sample according to the three-dimensional elastic wave.

[0142] Optionally, in an embodiment of the present application, the interference signals corresponding to the target scanning mode are respectively:

[0143]

[0144]

[0145]

[0146] wherein, is the interference signal corresponding to the first scanning, is the interference signal corresponding to the second scanning, is the interference signal corresponding to the third scanning, is a static interference signal of the pixel point, and , and respectively represent the amplitude and phase of the left and right fluctuations of the pixel point;

[0147] The static interference signal of the pixel point is obtained by averaging the interference signals of the three scans:

[0148]

[0149] wherein, is the static interference signal of the pixel point, is the interference signal corresponding to the first scan, is the interference signal corresponding to the second scan, is the interference signal corresponding to the third scan;

[0150] The amplitude and phase of the left and right fluctuations of the pixel point are respectively:

[0151]

[0152]

[0153] wherein, and are the fluctuation signals obtained by removing the static signal from the signals of the first two scans, is the amplitude of the right fluctuation of the pixel point, is the amplitude of the left fluctuation of the pixel point;

[0154] The fluctuation signal obtained by removing the static signal from the signals of the first two scans is:

[0155]

[0156]

[0157] wherein, is the interference signal corresponding to the first scan, is the interference signal corresponding to the second scan, is the static interference signal of the pixel point, and , and respectively represent the amplitude and phase of the left and right fluctuations of the pixel point.

[0158] Optionally, in an embodiment of the present application, the generating module 400 further comprises a transmission unit.

[0159] The transmission unit is configured to drive the contact probe to transmit the vibration to the sample to generate the two-dimensional elastic wave of the sample based on the frequency of the frequency-sweeping laser and the piezoelectric effect of the preset excitation system, and determine the two-dimensional imaging of the sample according to the two-dimensional elastic wave.

[0160] It should be noted that the foregoing explanation of the embodiment of the optical coherence elastography method is also applicable to the optical coherence elastography device of the embodiment, and thus will not be repeated here.

[0161] The optical coherence elastography device provided by the embodiment of the present application increases the imaging speed by about 300 times, reduces the two-dimensional imaging time from the order of seconds to milliseconds, and can realize dynamic two-dimensional imaging; reduces the three-dimensional imaging time to within 1 second, and can realize three-dimensional in-vivo imaging. Through the innovative imaging sequence design and imaging algorithm, the efficient collaborative operation of the laser, the scanning galvanometer and the excitation module is realized. Thus, the main limitation of the existing optical coherence elastography method, i.e., slow imaging speed, is solved. Specifically, the optical coherence elastography adopts the M-B scanning mode, and generally, the time required for two-dimensional imaging is in the order of seconds. Therefore, this method cannot be used for dynamic biological tissues. At the same time, the time required for three-dimensional imaging is about minutes, and this imaging speed cannot be used for in-vivo measurement.

[0162] Figure 10 The structure schematic diagram of the electronic device provided by the embodiment of the present application. The electronic device can include:

[0163] The memory 1001, the processor 1002 and the computer program stored in the memory 1001 and executable on the processor 1002.

[0164] The processor 1002 executes the program to realize the optical coherence elastography method provided in the above embodiments.

[0165] Further, the electronic device further includes:

[0166] The communication interface 1003 is used for communication between the memory 1001 and the processor 1002.

[0167] The memory 1001 is used to store the computer program executable on the processor 1002.

[0168] The memory 1001 can include a high-speed RAM memory, and can also include a non-volatile memory, such as at least one disk memory.

[0169] If the memory 1001, the processor 1002 and the communication interface 1003 are implemented independently, the communication interface 1003, the memory 1001 and the processor 1002 can be connected with each other through a bus and complete communication between each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For convenience of representation, Figure 10 Only one thick line is used to represent the bus in the figure, but it does not mean that there is only one bus or only one type of bus.

[0170] Optionally, in a specific implementation, if the memory 1001, the processor 1002 and the communication interface 1003 are integrated on a chip, the memory 1001, the processor 1002 and the communication interface 1003 can complete communication between each other through an internal interface.

[0171] The processor 1002 can be a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present application.

[0172] The embodiment also provides a computer readable storage medium, which stores a computer program, and the program is executed by a processor to implement the optical coherence elastography method.

[0173] The embodiment of the present application also provides a computer program product, which stores a computer program, and the program is executed by a processor to implement the optical coherence elastography method.

[0174] In the description of the application, reference to "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" means that a particular feature, structure, material, or characteristic being described is included in at least one embodiment or example of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment or example. Furthermore, the described specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples. In addition, the usage of "first", "second" and the like does not indicate any order but rather serves merely to name various components. Moreover, the usage of "top", "bottom", and the like is made for the purpose of illustration only and does not indicate any orientation. The terms "coupled" and "connected", along with their derivatives, can be used. It should be understood that these terms are not intended as synonyms for each other. Rather, particular features are described as being coupled or connected where the feature is in some way present, for example through shared use of one or more components, and can be communicatively, electrically, structurally, and / or mechanically connected, for example. Similarly, "coupled" or "connected" can be used to indicate that two or more members are either directly in contact or indirectly in contact through one or more intermediate members.

[0175] Furthermore, the terms "first", "second", and the like, merely denote different categories, and do not imply a relative importance or a specific order. Thus, features defined with "first", "second" and the like can include at least one of the features, either explicitly or implicitly. In the description of the application, the term "N" means at least two, for example two, three, etc., unless explicitly specified otherwise.

[0176] Any process or method descriptions or blocks in flow charts or otherwise described herein represent embodiments of modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps, and alternate implementations are possible. In some embodiments, the processes or methods described can be accomplished with one or more hardware items, for example, hardwired circuits, memory, logic circuits, look-up tables, microcode or the like, software programs, firmware programs, microcode routines, embedded logic, embedded software, or any combination thereof, which work together to cause a general purpose computer, a special purpose computer, or both, to perform the processes or methods described. The various embodiments further can interact with a user through one or more computer programs, software applications, firmware applications, operating systems, or the like, which interact with a user. Such software can be written in any of a variety of suitable programming languages and can be executed using a variety of suitable hardware and software configurations. It will be appreciated that computer programs, software applications, firmware applications, operating systems, or the like, can be written in any combination of one or more suitable programming languages, and that such software can be executed using one or more computing devices capable of netlist generation as described herein.

[0177] The logic and / or steps represented in flow diagrams or otherwise described herein, for example, can be considered as a sequence of executable instructions, and can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For purposes of this specification, a "computer-readable medium" can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The computer-readable medium can be a product of the manufacturing and / or processing. The computer-readable medium can include, but is not limited to, the following: an electronic connection (an electronic device with one or N wires), a portable computer diskette (a magnetic device), a RAM (random access memory), a ROM (read-only memory), an EPROM (erasable programmable ROM) or a Flash memory, an optical fiber, and a portable CD ROM. In addition, the computer-readable medium can even be paper or other suitable medium upon which the program is printed, as the program can be electronically captured, via the optically scanning of the paper or other suitable medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and stored in a computer memory.

[0178] It should be understood that aspects of the application can be implemented in hardware, software, firmware or combinations thereof. In the above embodiments, the N steps or methods can be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. As such, if implemented in hardware and in another embodiment, any of the following technologies, known in the art, or their combinations can be used: discrete logic circuitry having logic gates for implementing logic functions on data signals, application specific integrated circuits having appropriate combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), and the like.

[0179] Those of ordinary skill in the art can understand that all or part of the steps carried out by the above-mentioned embodiment methods can be completed by programs instructing relevant hardware, and the programs can be stored in a computer-readable storage medium. When the programs are executed, one or a combination of the steps of the method embodiments is included.

[0180] In addition, each function unit in each embodiment of the present application can be integrated in one processing module, or each unit can be physically present separately, or two or more units can be integrated in one module. The integrated module can be realized in the form of hardware or in the form of a software function module. When the integrated module is realized in the form of a software function module and sold or used as an independent product, it can also be stored in a computer readable storage medium.

[0181] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. An optical coherence elastography method, comprising: The method comprises the following steps: outputting laser meeting preset time periodicity condition and preset linear variation condition by using a sweep light source; receiving a trigger signal of the sweep light source by using a waveform generating card, and generating a driving signal containing an analog signal or a digital signal according to the trigger signal; scanning a sample according to the driving signal to generate a scanning result; applying mechanical excitation to the sample by using the driving signal based on the scanning result to generate two-dimensional elastic waves and three-dimensional elastic waves in the sample, and generating two-dimensional imaging and three-dimensional imaging of the sample according to the two-dimensional elastic waves and the three-dimensional elastic waves respectively; dividing the laser into reference arm laser and sample arm laser by using a coherent light path, and interfering the sample arm laser after reflection with the reference arm laser to generate an interference signal; reconstructing the interference signal into a sample structure image, extracting elastic waves in the sample based on the sample structure image, generating biomechanical information of the sample according to the elastic waves, and determining a final optical coherence elastography result according to the biomechanical information, the three-dimensional imaging and the two-dimensional imaging.

2. The optical coherence elastography method of claim 1, wherein, After the sample arm laser is interfered with the reference arm laser to generate an interference signal, the method further comprises: measuring the interference signal, and converting the interference signal into an analog signal of the sample; or, storing the interference signal to generate a digital signal of the sample.

3. The optical coherence elastography method of claim 1, wherein, The method of applying mechanical excitation to the sample by using the driving signal to generate two-dimensional elastic waves and three-dimensional elastic waves in the sample, and generating two-dimensional imaging and three-dimensional imaging of the sample according to the two-dimensional elastic waves and the three-dimensional elastic waves respectively, comprises: determining an imaging sequence of the sample by using the frequency of the sweep light source as a clock, and receiving a sine signal of the waveform generating card based on the imaging sequence; applying excitation to the sample by using the sine signal to implement a target scanning mode in the direction of a second direction axis while keeping still in the direction of a first direction axis; cyclically executing the target scanning mode three times until three-dimensional scanning of the sample meets a preset ending condition, generating three-dimensional elastic waves of the sample, and determining three-dimensional imaging of the sample according to the three-dimensional elastic waves.

4. The optical coherence elastography method of claim 3, wherein, The interference signals corresponding to the target scanning mode are respectively: wherein, is the interference signal corresponding to the first scan, is the interference signal corresponding to the second scan, is the interference signal corresponding to the third scan, is the static interference signal of the pixel point, and , and respectively represent the amplitude and phase of the fluctuation on the left and right sides of the pixel point. The static interference signal of the pixel point is obtained by averaging the interference signals of the three scans: wherein, is a static interference signal of the pixel point, is an interference signal corresponding to the first scan, is an interference signal corresponding to the second scan, is an interference signal corresponding to the third scan; The amplitude and phase of the left and right fluctuations of the pixel point are respectively: wherein, and is a fluctuation signal obtained by eliminating static signals from the first two scanning signals, is an amplitude of the fluctuation on the right side of the pixel point, is an amplitude of the fluctuation on the left side of the pixel point; The fluctuation signal obtained by eliminating the static signal from the first two scanning signals is: wherein, is the interference signal corresponding to the first scan, is the interference signal corresponding to the second scan, is the static interference signal of the pixel point, and , and respectively represent the amplitude and phase of the fluctuation on the left and right sides of the pixel point.

5. The optical coherence elastography method of claim 1, wherein, The method of applying mechanical excitation to the sample by using the driving signal to generate two-dimensional elastic waves and three-dimensional elastic waves in the sample, and generating two-dimensional imaging and three-dimensional imaging of the sample according to the two-dimensional elastic waves and the three-dimensional elastic waves respectively, further comprises: transmitting vibration to the sample by using a contact probe based on the frequency of the sweep laser and the piezoelectric effect of a preset excitation system to generate two-dimensional elastic waves of the sample, and determining two-dimensional imaging of the sample according to the two-dimensional elastic waves.

6. An optical coherence elastography apparatus, comprising: The method comprises: outputting laser meeting preset time periodicity condition and preset linear variation condition by using a sweep light source; The receiving module is configured to receive a trigger signal of the swept light source by using a waveform generator card, and generate a driving signal containing an analog signal or a digital signal according to the trigger signal. The scanning module is configured to scan a sample according to the driving signal, and generate a scanning result. The generating module is configured to apply mechanical excitation to the sample by using the driving signal based on the scanning result, so as to generate two-dimensional elastic waves and three-dimensional elastic waves in the sample, and generate two-dimensional imaging and three-dimensional imaging of the sample according to the two-dimensional elastic waves and the three-dimensional elastic waves respectively. The interference module is configured to divide the laser into reference arm laser and sample arm laser by using a coherent light path, and interfere the sample arm laser after reflection with the reference arm laser, so as to generate an interference signal. The imaging module is configured to reconstruct the interference signal into a sample structure image, extract elastic waves in the sample based on the sample structure image, generate biomechanical information of the sample according to the elastic waves, and determine a final optical coherence elastography result according to the biomechanical information, the three-dimensional imaging and the two-dimensional imaging.

7. The optical coherence elastography apparatus according to claim 6, wherein, Further comprising: The measuring module is configured to measure the interference signal after the interference of the sample arm laser after reflection with the reference arm laser, and convert the interference signal into an analog signal of the sample. Or, the storage module is configured to store the interference signal, so as to generate a digital signal of the sample.

8. An electronic device, comprising: Further comprising: A memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the optical coherence elastography method according to any one of claims 1-5.

9. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to implement the optical coherence elastography method according to any one of claims 1-5.

10. A computer program product comprising a computer program, characterized in that, The computer program is executed to implement the optical coherence elastography method according to any one of claims 1-5.

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