WO2015172322A1

WO2015172322A1 - Blood flow measuring device and method

Info

Publication number: WO2015172322A1
Application number: PCT/CN2014/077418
Authority: WO
Inventors: 王益民; 王辉; 郭曙光; 李鹏; 何卫红; 代祥松
Original assignee: 深圳市斯尔顿科技有限公司
Priority date: 2014-05-14
Filing date: 2014-05-14
Publication date: 2015-11-19
Also published as: CN104159505A; CN104159505B

Abstract

A blood flow measuring device and method. The blood flow measuring device comprises a light source (100), a first beam-splitting module (200), a reference arm module (300), a sample arm module (500) and a detection module (600). The sample arm module (500) comprises a rotatable mirror (503). The light source (100) emits light and the light is transmitted to the first beam-splitting module (200). The first beam-splitting module (200) respectively provides the received light to the reference arm module (300) and the sample arm module (500). The reference arm module (300) reflects the received light back to the first beam-splitting module (200) to form a reference light. When the rotatable mirror (503) is at a first rotation angle (M1), the light provided by the first beam-splitting module (200) is transmitted to an eye and a first signal light is formed. When the rotatable mirror (503) is at a second rotation angle (M2), the light provided by the first beam-splitting module (200) is transmitted to the eye and a second signal light is formed. The first and second signal lights are transmitted back to the first beam-splitting module (200) and, within the first beam-splitting module (200), respectively interfere with the reference light to generate first and second interference lights. The detection module (600) receives the first and second interference lights.

Description

Blood flow measuring device and method

Technical field

The present invention relates to the field of optoelectronic technology, and in particular, to a blood flow measuring device and method.

Background technique

Many retinal diseases are associated with abnormal blood flow to the eye, such as diabetic retinopathy, retinal vein occlusion, and age-related macular degeneration. In the study of glaucoma, lack of blood supply to the retina is considered to be a possible cause of the development and progression of glaucoma. Therefore, measurement of retinal blood flow is important for clinical diagnosis, treatment, and research of retinal diseases.

Optical Coherence Tomography (OCT) is a non-invasive detection technique. It is widely used in the imaging of living structures in biological tissues. By measuring the scattered light associated with depth, OCT provides a highly resolved, highly sensitive tissue structure. At the same time, OCT technology can also detect the Doppler shift of scattered light to obtain motion information of fluids and samples, and is therefore suitable for measuring blood flow in the retina. Unfortunately, the frequency shift detected by the single-beam Doppler OCT is only related to the blood flow velocity in the direction of the probe beam, and the blood flow information perpendicular to the direction of the probe light cannot be directly obtained from the Doppler shift, and the intravascular can not be obtained. The actual flow rate.

In order to solve the above problems, a series of techniques have been developed to obtain the actual flow rate in the blood vessel:

(1), through three-dimensional scanning of the retina, obtain the direction of the blood vessels in the retina in space, thereby determining the Doppler angle of the probe light, and then using the Doppler angle to calculate the actual flow velocity. However, this method is less accurate because the blood vessels of the retina and the probe beam are close to vertical. In addition, by continuously scanning two planes or rings, the space vector of the blood vessel to be tested is determined, and then the Doppler angle is calculated to obtain the actual flow velocity. The measurement results of this method are affected by eye movements, and it can only measure blood vessels around the optic disc and cannot measure blood flow in other areas of the retina. In addition, flow information can be obtained by calculating the Doppler signal of the cross-section of the blood vessel, but this measurement method is only applicable to large vessels that are steep toward the optic disc. Blood flow to other areas of the retina cannot be detected.

(2) Using multiple beam, multi-angle probe light to scan the same point in the sample to obtain the true fluid velocity in the blood vessel. The OCT probe light is split into two beams by a glass plate. The two beams are concentrated in the fluid to form a double beam. The two-angle illumination method can be obtained by analyzing the Doppler shift detected by the two beams. - - The actual fluid velocity into the pipe. This method is not suitable for frequency domain OCT systems due to the delay of the two paths of light. Alternatively, a dual beam OCT system with polarized beam splitting can be used to measure the flow rate and flow rate in the retinal blood vessels, or a DOVE prism can be synchronized with the OCT scanning mechanism to achieve a circular scan of the dual beam on the retina. However, these two-beam systems are composed of two Michelson interferometers, which are complicated in structure and difficult to adjust, and because of the safety considerations of the probe light, the power of each probe light is much lower than that of the single-beam system, which reduces the double-beam OCT. The sensitivity of the system increases the phase noise of the system. Summary of the invention

In view of the above, an object of the present invention is to provide a blood flow measuring device which realizes single beam, double angle detection and scanning through a rotatable mirror to obtain blood flow of blood vessels in the eye, and the device has a simple structure. , Easy adjustment, high measurement accuracy, etc., to meet the requirements of use.

The present invention also provides a blood flow measuring method based on the above blood flow measuring device. In order to solve the above technical problem, the present invention provides a blood flow measuring device for measuring blood flow of a blood vessel in an eye, comprising a light source, a first beam splitting module, a reference arm module, a sample arm module, and a detecting module, wherein The sample arm module includes a rotatable mirror,

The light source emits light and transmits the light to the first beam splitting module, and the first beam splitting module supplies the received light to the reference arm module and the sample arm module, respectively, and the reference arm module receives The received light is transmitted back to the first beam splitting module to form reference light;

And when the rotatable mirror is at a first rotation angle, reflecting the light provided by the first beam splitting module to the eye and generating signal light;

And when the rotatable mirror is at a second rotation angle, reflecting the light provided by the first beam splitting module to the eye and generating signal light;

The signal light is transmitted back to the first beam splitting module and interferes with the reference light in the first beam splitting module to generate interference light, and the detecting module receives the interference light.

The sample arm module further includes a motor, the motor has a rotating shaft, and the rotatable mirror is fixed on the rotating shaft, and the rotating mirror drives the rotatable mirror to rotate correspondingly.

The sample arm module further includes a scanning unit, a dichroic mirror and an ophthalmoscope, the scanning unit includes a first scanning element and a second scanning element, and the first scanning element receives the rotatable mirror - reflecting light and reflecting to the second scanning element, the second scanning element reflecting the received light to the dichroic mirror, the dichroic mirror reflecting the received light to the ophthalmoscope The ophthalmoscope concentrates light onto the eye.

The sample arm module further includes a collimating lens disposed between the rotatable mirror and the first scanning element, and the relay lens is disposed on the second scan Between the component and the dichroic mirror.

The sample arm module further includes a preview module, the preview module includes an imaging lens and a camera, and light emitted by the illumination source is irradiated to the eye, and reflection occurs in the eye, and the reflected light transmits the reflected light The ophthalmoscope, the dichroic mirror, and the imaging mirror are then passed to the camera to be photographed by the camera.

Wherein, the device further comprises a computer, the computer receiving the signal processed by the detecting module, and controlling the rotation of the motor, the first scanning element and the second scanning element. The present invention also provides a blood flow measuring method, characterized in that it comprises at least the following steps: when the rotatable mirror is at a first rotation angle, transmitting probe light to the blood vessel and generating a first signal light, The first signal light after the interference is processed to obtain a first phase shift signal; when the rotatable mirror is at the second rotation angle, the probe light is transmitted to the blood vessel and the second signal light is generated, after the interference The second signal light is processed to obtain a second phase shift signal; and the blood flow of the blood vessel is calculated according to the first phase shift signal and the second phase shift signal.

The first signal light after the interference is obtained by interfering with the first signal light when receiving the first signal light;

The interfering second signal light is obtained by interfering with the second signal light when the second signal light is received.

After the second phase shift signal is obtained after processing the interference second signal light, the method further includes:

Correcting the first phase shift signal.

After the second phase shift signal is obtained after processing the interference second signal light, the method further includes: A pair of said second phase shift signals are corrected.

The correcting the second phase shift signal includes:

Obtaining a relationship between the first phase shift signal and the second phase shift signal over time by scanning by the second scanning element;

The second phase shift signal is corrected using an interpolation calculation.

Wherein, before calculating the blood flow of the blood vessel according to the first phase shift signal and the second phase shift signal, the method further includes:

Measuring an angle between an axial direction of the blood vessel and an X direction; wherein, when the rotatable mirror is at a first rotation angle, a first direction of light entering the eye and a second rotation of the rotatable mirror At an angle, the second direction of the light entering the eye constitutes the XZ plane, which is parallel to the X-axis of the XZ plane.

The blood flow measuring device and method provided by the present invention controls the rotation of the rotatable mirror by a motor such that the rotatable mirror is at a first rotation angle and obtains a first phase shift signal, or the rotatable mirror is made At a second rotation angle and obtaining a second phase shift signal, the flow rate of the blood is obtained by processing the first phase shift signal and the second phase shift signal. The blood flow measuring device provided by the invention has the advantages of simple structure, convenient operation, high precision of measurement results, and the like when measuring blood flow.

DRAWINGS

In order to more clearly illustrate the technical solutions of the present invention, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the present invention, which are common in the art. For the skilled person, other drawings can be obtained from these drawings without any creative work.

1 is a schematic structural view of a blood flow measuring device according to an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of another reference arm module according to an embodiment of the present invention.

Figure 3 is a schematic view showing the structure of the sample arm module shown in Figure 1.

Fig. 4 is a view showing the positional relationship between the first direction vector and the second direction vector and the blood vessel.

Figure 5 is a schematic illustration of the scanning trajectory of the probe light within the blood vessel. Fig. 6 is a schematic diagram showing the principle of realizing the scanning trajectory shown in Fig. 4.

Fig. 7 is a schematic view showing the scanning of the angle between the axial direction of the blood vessel and the X direction.

FIG. 8 is a schematic flow chart of a blood flow measurement method according to a first embodiment of the present invention.

9 is a schematic flow chart of a blood flow measurement method according to a second embodiment of the present invention.

Figure 10 is a graph showing changes in the first phase shift signal and the second phase shift signal over time.

detailed description

BRIEF DESCRIPTION OF THE DRAWINGS The technical solutions in the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without the creative work are all within the scope of the present invention.

Referring to Figure 1, an embodiment of the present invention provides a blood flow measuring device for measuring blood flow of a blood vessel in an eye 800, which may be the eye of a human eye or other animal. The blood flow measuring device includes a light source 100, a first beam splitting module 200, a reference arm module 300, a sample arm module 500, a detecting module 600, and a computer 700, and the light source 100 emits light and transmits the light to the first beam splitting module. 200. The first beam splitting module 200 divides the received light into two beams and provides the reference arm module 300 and the sample arm module 500, respectively. One of the light is transmitted to the reference arm module 300, which transmits the received light back into the beam splitter module 200 to form reference light, and the other beam passes through the sample arm module 500. After being incident into the eye 800, the signal light is scattered by the blood vessel in the eye 800 and returned to the first beam splitting module 200, and the signal light interferes with the reference light to generate interference light, the detecting Module 600 receives and collects the interference light and transmits the signal to computer 700, which processes the signal.

In an embodiment of the present invention, the light source 100 may be a super luminescent diode that emits near-infrared detection light, and the probe light is transmitted to the first beam splitting module 200, and the first beam splitting module 200 may It is a 2 x 2 fiber splitter that splits the received probe light into two beams and supplies them to the reference arm module 300 and the sample arm module 500, respectively.

In the embodiment of the present invention, the reference arm module 300 includes a reference mirror 303, wherein the reference mirror 303 can be a planar mirror, and the probe light provided by the first beam splitting module 200 passes the reference The mirror 303 is vertically reflected and returned to the first beam splitting module 200 to form reference light.

Referring to FIG. 2, FIG. 2 is another reference arm module 900 according to an embodiment of the present invention. The reference arm module 900 includes a second beam splitting module 901, and the second beam splitting module 901 can be 1 X. The 2 beam splitter has an opening at one end and two openings at the other end and the two openings are connected by an optical path of the optical fiber. The probe light provided by the first beam splitting module 200 is incident from the one end with one opening into the second beam splitting module 900, and then exits from the two openings at the other end respectively, and propagates in the optical fiber and returns to the respective The second beam splitting module 900 finally exits from an end with an opening and returns to the first beam splitting module 900 to form reference light.

It can be understood that, in other embodiments of the present invention, the reference arm module may have other structural design and placement manners, such as the second beam splitting module 901 may be disposed on the first beam splitting module 200 and Between the detection modules 600, the light provided by the first beam splitting module 200 to the reference arm module 901 is transmitted through the optical fiber to the second beam splitting module 901 to form reference light (from one end with two openings) One opening is incident). The signal light reflected back by the sample arm module 500 is incident into the second beam splitting module 901 (incident from another one of the ends with two openings) and interferes with the reference light to form interference light, The interference light is transmitted from the end with an opening and then transmitted to the detecting module 600. In addition, the reference arm module has other designs, which are not limited herein.

It should be noted that, in an embodiment of the present invention, the blood flow measuring device further includes a first lens 400, and the first lens 400 is disposed in the first beam splitting module 200 and the sample arm module 500. The probe light provided by the first beam splitting module 200 is transmitted to the sample arm module 500 after being transmitted through the first lens 400.

Referring to FIG. 3 together, in the embodiment of the present invention, the sample arm module 500 includes a motor 502, a rotatable mirror 503, a scanning unit, a dichroic mirror 508, and an ophthalmoscope 509. The motor 502 has a rotating shaft, the rotatable mirror 503 is fixed on the rotating shaft, and the motor 502 rotates to rotate the rotating shaft, so that the rotatable mirror 503 rotates with the motor 502. Rotating to inject the probe light provided by the first beam splitting module 200 into the eye 800 at different angles.

Specifically, please refer to FIG. ₄ , in the embodiment of the present invention, the scanning unit includes a first scanning component 505 and a second scanning component 506, wherein the first scanning component 505 can be an X-direction scanning component. The second scanning element 506 can be a Y-direction scanning element. The motor 502 rotates and drives the rotatable mirror 503 to rotate when the rotatable mirror 503 is at a first rotation angle M _{l 5} In this case the rotatable mirror 503 reflecting the first partial optical beam provided by the module 200 to the first scanning element 505, after passing through the first scanning element 505 to the second reflector Scanning element 506. The second scanning element 506 reflects the probe light incident on the surface thereof to the dichroic mirror 508, and the dichroic mirror 508 can be a dichroic mirror having a high reflectivity to the probe light, the two-color The mirror 508 reflects the probe light to the ophthalmoscope 509, and the eyepiece 509 converges to the blood vessel in the eye 800. The blood vessel B scatters the probe light to generate a first signal light. The reference light interferes to generate first interference light, and the detection module 600 receives the first interference light and is collected and processed by the computer 700 to obtain a first phase shift signal. Wherein, when the rotatable mirror 503 is at the first rotation angle, the incident path of the probe light may refer to the path 1 indicated by the solid line in FIG. 3, and the probe light is incident into the eye 800 via the path 1. The first direction vector can be represented by Si (as shown in Figure 4).

When the motor 502 is rotated through a predetermined angle, such as 180 degrees, the rotatable mirror 503 is at a second rotational angle M ₂ . At this time, the rotatable mirror 503 reflects the light provided by the first beam splitting module 200 to the first scanning element 505, is reflected by the first scanning element 505, and is transmitted to the second scanning element. 506. The second scanning element 506 reflects the probe light incident on the surface thereof to the dichroic mirror 508, which may be a dichroic mirror having a high reflectivity to the probe light, the two-color The mirror 508 reflects the probe light to the ophthalmoscope 509, and is concentrated by the ophthalmoscope 509 to the blood vessel B in the eye 800. The blood vessel B scatters the probe light to generate a second signal light, and the second signal light returns to the first beam splitting module 200 in a direction opposite to the incident light and interferes with the reference light to generate The second interference light, the detection module 600 receives the second interference light and is collected by the computer 700 to obtain a second phase shift signal. Wherein, when the rotatable mirror 503 is at the second rotation angle M ₂ , the incident path of the probe light may refer to the path 2 indicated by a broken line in FIG. 3 , and the probe light is incident into the eye 800 via the path 2 . The second direction vector can be represented by S ₂ (as shown in FIG. 4).

It should be noted that the sample arm module 500 further includes a second lens 501 disposed between the first lens 400 and the rotatable mirror 503, and the second lens 501 The light provided by the first lens 400 converges to the surface of the rotatable lens 503.

It should be noted that the sample arm module 500 further includes a collimating lens 504 and a relay lens 507. The collimating lens 504 is disposed between the rotatable mirror 503 and the first scanning element 505, and the detecting light reflected by the rotatable mirror 503 is transmitted through the collimating lens 504 to reach the First scanning element 505. The relay lens 507 is disposed between the second scanning element 506 and the dichroic mirror 508, and the probe light reflected by the second scanning element 506 is transmitted through the relay lens 507 to reach the dichroic mirror 508.

It should be noted that the sample arm module 500 further includes a preview module, and the preview module includes an imaging lens 510 and a camera 511, and light emitted by an illumination source (not shown) is irradiated to the eye 800, and Reflection occurs in the eye 800, the reflected light is transmitted through the ophthalmoscope 509 to the dichroic mirror 508, and the dichroic mirror 508 has a high transmittance to the light emitted by the illumination source, and the reflected light sequentially transmits the After the dichroic mirror 508 and the imaging lens 510 arrive at the camera 511, the image captured by the camera 511 is displayed on the computer display screen for the operator to understand the eye. Information about 800 for further operation.

It should be noted that, in the embodiment of the present invention, the first scanning element 505 and the second scanning element 506 may be galvanometers, and the first scanning element 505 has an effect of performing X-direction scanning on the probe light. The second scanning element 506 has a function of scanning the detection beam in the Y direction. Specifically, as shown in FIG. 4, the first direction vector Si and the second direction vector S ₂ form an XZ plane, and when the rotatable mirror 503 is at the first rotation angle, the scanning unit rotates and Detecting the detection light whose incident direction is the first direction vector Si, when the rotatable mirror 503 is at the second rotation angle M ₂ , the scanning unit rotates and drives the detection direction of the second direction vector S ₂ The light is scanned to ensure that the probe light can detect the blood vessel B. The computer 700 according to the received signal a first mobile phase, the second phase and the movement signal related parameters (e.g., wavelength of the probe light, the refractive index of the blood, a first direction and the second direction vector Si sandwiched between the _two vector S The angle between the axial direction of the blood vessel and the blood vessel and the X direction, etc.), the average blood flow rate of the blood vessel B is calculated.

It should be noted that, in the embodiment of the present invention, according to the orientation and distribution of the blood vessel B, the scanning unit can drive the detection by the cooperation of the first scanning element 505 and the second scanning unit 506. The light beam realizes various scanning modes such as X-direction scanning, Y-direction scanning, or oblique line scanning, so that the detection light adjusts the scanning direction according to the actual direction of the blood vessel B.

It should be noted that, in the embodiment of the present invention, the blood flow measuring device can also implement a circular sweep by the cooperation of the first scanning element 505, the second scanning element 506 and the motor 502. - - Trace to quickly obtain blood flow from all blood vessels throughout the eye 800. Specifically, as shown in FIG. 5, when the rotatable mirror 503 is at the first rotation angle, the computer 700 controls the synchronous rotation of the motor 502 with the first scanning element 505 and the second scanning element 506, thereby The detection ray is circularly scanned around the optic disc region on a circumference C. Figure 6 depicts how such scanning can be accomplished: First, the first scanning element 505, the second scanning element 506 controls the detection beam onto the circumference. S point, at this time, if the first scanning element 505 and the second scanning element 506 remain stationary, the motor 502 rotates 360 degrees, and the probe beam will move circumferentially around the tapered surface Co. When the motor 502 rotates synchronously with the first scanning element 505 and the second scanning element 506, the detecting beam will complete a circular motion along the direction of the space vector shown by the solid line (the inner ring of the circle shown in FIG. 6). Thus, the first phase shift signal corresponding to each blood vessel can be obtained. When the spot returns to point S, the motor 502 quickly switches a phase π (i.e., turns 180 degrees), at which point the probe beam switches to the direction indicated by the dashed line (outer ring shown in Figure 6). Then, the first scanning element 505 and the second scanning element 506 are synchronously moved with the motor 502 to drive the detecting beam to perform a circular motion along the direction of the space vector indicated by the broken line, thereby obtaining a second phase moving signal corresponding to each blood vessel. The scan is performed for a predetermined time (e.g., 2 seconds), and the computer 700 can collect a series of phase shift signals. After the above scanning is completed, the scanning beam is scanned for a fast multi-ring to obtain a circular three-dimensional image. As shown in Fig. 7, the angle β between the axial direction of all the blood vessels and the X direction can be determined. At this time, the computer 700 obtains the total blood flow rate in the eye 800 by calculating the average blood flow rate of each blood vessel and superimposing it.

The blood flow measuring device provided by the embodiment of the present invention controls the rotation of the rotatable mirror 503 by the motor 502 such that the rotatable mirror 503 is at the first rotation angle Mi and obtains a first phase shift signal, or The rotatable mirror 503 is at a second rotation angle M ₂ and obtains a second phase shift signal, and the actual flow rate of the blood is obtained by processing the first phase shift signal and the second phase shift signal and thereby obtaining blood. flow. The blood flow measuring device provided by the embodiment of the invention has the advantages of simple structure, convenient operation and high precision of measurement results when measuring blood flow.

Referring to FIG. 8 together, an embodiment of the present invention provides a blood flow measurement method, which includes at least the following steps.

S101, when the rotatable mirror is at the first rotation angle Mi, transmitting the probe light to the blood vessel and generating the first signal light, and processing the first signal light after the interference to obtain the first phase shift - - Signal.

Specifically, in the embodiment of the present invention, the computer 700 can control the rotation of the motor 502 to cause the rotatable mirror 503 fixed on the motor 502 to be at the first rotation angle M _l at this time, the light source The probe light emitted by 100 will propagate along the solid path 1 as shown in FIG. 3 to the vasospasm of the eye 800. The vasospasm scatters the probe light to generate a first signal light, and the first signal light is transmitted back to the first beam splitting module 200 and interferes with the reference light, and the interfered first signal light is detected by the detecting Module 600 receives and communicates to computer 700, which processes the first signal light after interference to generate a first phase shift signal.

5102, when the rotatable mirror is at the second rotation angle Μ ₂ , transmitting the probe light to the blood vessel and generating the second signal light, and processing the second signal light after the interference to obtain the second phase shift signal .

Specifically, in the embodiment of the present invention, the computer 700 can switch the rotatable mirror 503 fixed on the motor 502 from the first rotation angle to the second rotation angle by controlling the rotation of the motor 502. M ₂ , at this time, the probe light emitted by the light source 100 will propagate to the blood vessel B of the eye 800 along the dashed path 2 as shown in FIG. 3 . The blood vessel B scatters the probe light to generate a second signal light, and the second signal light is transmitted back to the first beam splitting module 200 and interferes with the reference light, and the interfered second signal light is detected by the detecting Module 600 receives and communicates to computer 700, which processes the interfered second signal light to generate a second phase shift signal.

5103. Calculate a blood flow of the blood vessel according to the first phase shift signal and the second phase shift signal.

The computer 700 calculates the blood flow of the blood vessel B based on the received first phase shift signal and the second phase shift signal.

The blood flow measuring method according to the first embodiment of the present invention controls the rotation angle of the rotatable mirror 503 to respectively generate a first phase shift signal and a second phase shift signal, and passes the first phase shift signal and the second phase. The moving signal calculates the blood flow of the blood vessel B, and the measuring method has the advantages of small error in measurement result and simple operation process.

Referring to FIG. 9, a second embodiment of the present invention provides a blood flow measuring method, which includes at least the following steps.

S201, transmitting the probe light to the blood vessel when the rotatable mirror is at the first rotation angle - - and generating a first signal light, and processing the first signal light after the interference to obtain a first phase shift signal.

Specifically, in the embodiment of the present invention, the computer 700 can control the rotation of the motor 502 to cause the rotatable mirror 503 fixed on the motor 502 to be at the first rotation angle M _l at this time, the light source The probe light emitted by 100 will propagate along the solid line path 1 as shown in FIG. 3 to the blood vessel B of the eye 800, and the blood vessel B scatters the probe light to generate a first signal light, which is transmitted back to the first signal light. The first beam splitting module 200 interferes with the reference light, and the interfered first signal light is received by the detecting module 600 and transmitted to the computer 700, and the computer 700 processes the interfered first signal light. , generating the first phase shift signal

S202, when the rotatable mirror is at the second rotation angle Μ ₂ , transmitting the probe light to the blood vessel and generating the second signal light, and processing the second signal light after the interference to obtain the second phase shift signal.

Specifically, in the embodiment of the present invention, the computer 700 controls the rotatable mirror 503 fixed on the motor 502 by controlling the rotation of the motor 502 (eg, the motor 502 is rotated through 180 degrees). The first rotational angle is switched to the second rotational angle M ₂ , at which time the probe light emitted by the light source 100 will propagate along the dashed path 2 as shown in FIG. 3 to the blood vessel B of the eye 800, the blood vessel B scattering Generating a second signal light after detecting the light, the second signal light is transmitted back to the first beam splitting module 200 and interferes with the reference light, and the interfered second signal light is received by the detecting module 600 and transmitted To the computer 700, the computer 700 processes the second signal light after the interference to generate a second phase shift signal Φ ₂ .

S203. Correct the second phase shift signal Φ ₂ .

In an embodiment of the present invention, the first phase shift signal 1 and the second phase shift signal Φ ₂ are not coincident with each other, and the blood flow in the blood vessel is pulsating, blood at different times The flow rate is different, so the computer 700 needs to correct the first phase shift signal 1, and the correction process includes the following steps:

First, the relationship between the first phase shift signal 1 and the second phase shift signal Φ ₂ over time is obtained by scanning by the scanning unit.

Specifically, please refer to FIG. 3 and FIG. 10 together. With the cooperation of the motor 502, the scanning unit drives the first plane and the second direction vector S ₂ formed by the beam to the first direction vector Si and the x-axis. Y axis - - The formed second plane is alternately scanned for a predetermined time, such as 2 seconds, to obtain a time-dependent phase shift signal profile (as shown in Figure 10). Wherein, when the black dot is the first rotation angle of the rotatable mirror 503, the computer 700 collects the first phase shift signal Φ white at different time points on the first plane as the rotatable When the mirror 503 is at the second rotation angle Μ ₂ , the second phase shift signal Φ ₂ measured by the computer 700 at different time points on the second plane.

It should be noted that, in the embodiment of the present invention, according to the orientation and distribution of the vasospasm, the scanning unit can drive the detection by the cooperation of the first scanning element 505 and the second scanning unit 506. The light beam realizes various scanning modes such as X-direction scanning, Υ direction scanning or oblique line scanning, and the above-mentioned scanning of the first plane and the second plane is only one possible scanning mode of the present invention, and in other embodiments of the present invention, The scanning unit can also drive the light beam to scan along other planes of the space according to the direction of the vasospasm.

Then, the second phase shift signal Φ ₂ is corrected by interpolation calculation.

Specifically,, O _al mobile phase is a first signal obtained by scanning moment t †, O _b2 for the second mobile phase timing signal _b obtained by scanning 10 t shown in FIG. Processor measured in a first plane of the first mobile phase signal interpolation calculation to obtain the first movement signal phase value of the time t _b t and the first phase of the movement signal value _b and time t o _a2 a first phase movement signal o _al _a time are compared to obtain k = O _al / O _a2. The second phase shift signal O _b2 at time t _{b is} multiplied by k, so that the second phase shift signal Φ _Μ , O _bl =kO _b2 at time t _a can be obtained.

It can be understood that, in other embodiments of the present invention, the processor may also fit the fitting equation of the phase shift signal and time by other fitting algorithms, and then correct the second phase shift signal Φ ₂ . The first phase shift signal and the second phase shift signal at the same time are obtained, and are not limited to the interpolation algorithm provided by the embodiment of the present invention.

It can be understood that, in other embodiments of the present invention, the processor may further perform the interpolation calculation on the first phase shift signal, such as by performing interpolation calculation on the second phase shift signal measured on the second plane. obtained at the time t _a second phase of the movement signal t is then moved a second phase signal Φ _½ second time with t _B phase signal Φ _½ _a moving time compared to obtain k = b ₂ /. T _a k multiplied with the time to a first mobile phase signal O _al, t thus obtained to a first mobile phase timing signal Φ _b _Μ ,, D _bl = kO _al. - -

5204. Measure an angle between an axial direction of the blood vessel and an X direction.

In the embodiment of the present invention, when calculating the flow rate of the blood vessel B, the processor first needs to obtain an angle β between the axial direction of the blood vessel B to be tested and the X direction. Wherein, when the mirror is at the first rotation angle, when the probe enters the first direction vector Si of the eye 800 and the mirror is at the second rotation angle M ₂ , the light enters the second direction vector of the eye S ₂ constitutes an XZ plane which is parallel to the X-axis of the XZ plane. The angle β is as shown in Fig. 4, and the angle β can be obtained only by obtaining a spatial distribution of the desired vasospasm.

5205. Calculate a blood flow of the blood vessel according to the first phase shift signal and the second phase shift signal.

In the embodiment of the present invention, the first phase shift signal O _al and the probe light measured by the probe light at the first rotation angle of the rotatable mirror 503 are at the second rotation angle M of the rotatable mirror 503. ₂ measured second phase shift signal Φ _Μ , that is, the flow rate of the vasospasm at time t _a can be obtained ^

Where λ. To detect the center wavelength of light, "for the refractive index of blood, τ is the time interval between two adjacent scans, which is the angle between the first direction vector Si and the second direction vector S ₂ (see Figure 4). Shown), β is the angle between the axial direction of the blood vessel and the X direction. Considering the pulsation of blood flow, the flow velocity of blood in the blood vessel at any time can be expressed as:

V(y, z,t) = v _A (y, z)P(t) The processor obtains the average flow of blood in the blood vessel B by integrating the space and time:

- - where T is the pulsation period of the blood flow, and P(t) is the blood flow pulsation function in the vasospasm measured as shown in FIG.

It should be noted that the blood flow measurement method provided by the embodiment of the present invention can also quickly measure the blood flow of all blood vessels in the eye 800, that is, the total blood flow of the eye 800. Specifically, the motor 502 cooperates with the first scanning element 505 and the second scanning element 506 to effect a circular scan of the eye 800. As shown in FIG. 5, when the rotatable mirror 503 is at a first rotation angle, the computer 700 controls the synchronous rotation of the motor 502 with the first scanning element 505 and the second scanning element 506. Thereby the detection light is circularly scanned around the optic disc region on a circumference C. Figure 6 depicts how such scanning is achieved: First, the first scanning element 505 and the second scanning element 506 control the detection beam to At point S on the circumference, if the first scanning element 505 and the second scanning element 506 remain stationary and the motor 502 rotates 360 degrees, the probe beam will move circumferentially around the tapered surface Co. When the motor 502 rotates synchronously with the first scanning element 505 and the second scanning element 506, the probe beam will complete a space vector direction along the solid line (the inner ring of the circle shown in FIG. 6). The circular motion, thus obtaining the first phase shift signal corresponding to each blood vessel. When the spot returns to point S, the motor 502 quickly switches a phase π, at which point the beam will switch to the direction indicated by the dashed line (outer ring shown in Figure 6). Then, the first scanning element 505 and the second scanning element 506 move synchronously with the motor 502 to drive the light beam to move in a circular motion along the direction of the space vector indicated by the broken line, so as to obtain a second phase shift corresponding to each blood vessel. The signal, scanned for a predetermined time (e.g., 2 seconds), the computer 700 can collect a series of phase shift signals. After the above scanning is completed, the scanning beam is scanned for a fast multi-ring to obtain a circular three-dimensional image. As shown in Fig. 7, the angle β between the axial direction of all the blood vessels and the X direction can be determined. At this time, using the formulas (1) to (3), the computer 700 obtains the total blood flow rate in the eye 800 by calculating the average blood flow rate of each blood vessel and superimposing it.

In summary, the blood flow measurement method provided by the second embodiment of the present invention controls the rotation angle of the rotatable mirror 503 to generate a first phase shift signal and a second phase shift signal, respectively, and After the phase shift signal or the second phase shift signal is corrected, the blood flow direction, the pulsation and the period are obtained by scanning, and the blood flow rate of the blood vessel fistula and the total blood flow rate in the eye 800 are obtained by integral calculation. The measuring method Easy to operate, less error in measurement results, etc. - - Point.

The above is a preferred embodiment of the present invention, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present invention. These improvements and retouchings are also considered. It is the scope of protection of the present invention.

Claims

Rights request

A blood flow measuring device for measuring blood flow of a blood vessel in an eye, comprising: a light source, a first beam splitting module, a reference arm module, a sample arm module and a detecting module, wherein the sample arm module Includes a rotatable mirror,

The signal light is transmitted back to the first beam splitting module and respectively interferes with the reference light to generate interference light in the first beam splitting module, and the detecting module receives the interference light.

2. The apparatus according to claim 1, wherein the sample arm module further comprises a motor, the motor has a rotating shaft, the rotatable mirror is fixed on the rotating shaft, and the motor rotates when the motor rotates The rotatable mirror rotates accordingly.

3. The apparatus according to claim 2, wherein the sample arm module further comprises a scanning unit, a dichroic mirror and an ophthalmoscope, the scanning unit comprising a first scanning element and a second scanning element, the first A scanning element receives light reflected by the rotatable mirror and reflects to the second scanning element, the second scanning element reflects the received light to the dichroic mirror, the dichroic mirror reflects the received light To the ophthalmoscope, the ophthalmoscope concentrates light to the eye.

4. The apparatus according to claim 3, wherein the sample arm module further comprises a collimating lens and a relay lens, the collimating lens being disposed between the rotatable mirror and the first scanning element The relay lens is disposed between the second scanning element and the dichroic mirror.

5. The apparatus according to claim 3, wherein the sample arm module further comprises a preview module, the preview module includes an imaging lens and a camera, and light emitted by the illumination source is irradiated to the eye, and Reflection occurs in the eye, and the reflected light is transmitted through the ophthalmoscope, the dichroic mirror, and the imaging mirror to the camera, and is captured by the camera.

6. The apparatus according to claim 3, wherein the apparatus further comprises a computer, the computer receiving a signal processed by the detecting module, and controlling the motor, the first scanning element, and the The rotation of the second scanning element is described.

7. A blood flow measuring method, characterized in that it comprises at least the following steps:

When the rotatable mirror is at the first rotation angle, transmitting the probe light to the blood vessel and generating the first signal light, and processing the interference first signal light to obtain the first phase shift signal; When the rotatable mirror is at the second rotation angle, transmitting the probe light to the blood vessel and generating the second signal light, and processing the interference second signal light to obtain the second phase shift signal; and according to the first The phase shift signal and the second phase shift signal calculate blood flow of the blood vessel.

8. The method of claim 7 wherein:

The interfering first signal light is obtained by interfering with the first signal light when receiving the first signal light;

The method according to claim 7, wherein after the processing of the second signal light after the interference to obtain the second phase shift signal, the method further includes:

Correcting the first phase shift signal.

The method according to claim 7, wherein after the processing of the second signal light after the interference, the second phase shift signal is obtained, the method further includes: The second phase shift signal is corrected.

11. The method of claim 10, wherein modifying the second phase shift signal comprises:

Obtaining a relationship between the first phase shift signal and the second phase shift signal over time by scanning by the scanning unit; and

The second phase shift signal is corrected using an interpolation calculation.

12. The method according to claim 7, wherein before calculating the blood flow of the blood vessel according to the first phase shift signal and the second phase shift signal, the method further comprises:

Measuring an angle between an axial direction of the blood vessel and an X direction;

Wherein, when the rotatable mirror is at the first rotation angle, when the first direction vector of the light entering the eye and the rotatable mirror are at the second rotation angle, the second direction vector of the light entering the eye constitutes The XZ plane, the X direction being parallel to the X axis of the XZ plane.