JP7276841B2 - Blood flow evaluation device. - Google Patents

Description

The present invention relates to a blood flow evaluation device for measuring the state of peripheral arteries in a living body, and more specifically, a blood flow evaluation device that enables more specific prediction of diseases in the central vascular system for diagnosing peripheral artery diseases. Regarding.

Peripheral artery disease, commonly called PAD (Peripheral Arterial Disease), is a disease caused by narrowing of arteries and restriction of blood flow due to the formation of lipid deposits in blood vessels, similar to coronary artery disease of the heart. PAD often develops in the lower extremities, and if PAD is left untreated, it becomes difficult to walk, and if it progresses to a severe stage, gangrene develops in the toes, leading to amputation of the lower extremities in some cases. PAD patients also often have narrowed arteries elsewhere in the body. Therefore, PAD patients are considered to be at high risk of "myocardial infarction" or "cerebral infarction".

As a general diagnostic method for PAD, there is an examination of the ankle brachial pressure index (ABI). An ABI test measures blood pressure in the ankle and upper arm and compares the blood pressure readings to see if there is a problem with blood flow. Therefore, if the ankle joint blood pressure is lower than the brachial blood pressure, it is suspected that there is a problem with the arteries from the heart to the legs. In particular, when the blood flow in the legs becomes poor, the blood pressure in the legs becomes extremely lower than the blood pressure in the upper arm, and peripheral arterial disease is suspected. However, in this examination, there is a problem that it is difficult to understand which part of the peripheral blood vessel is necrotic and which part should be cut and treated. Therefore, in some cases, the cleaved site was unavoidably defined to be larger than necessary.

On the other hand, as a technique to objectively know the peripheral circulatory state of the living body, after putting pressure on the finger, wrist, arm, etc. to put the peripheral part in an ischemic state, release it and optically measure the surface of the peripheral part at that time. Thus, a method for objectively measuring the degree of peripheral circulation has been disclosed (see Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 11-089808 Special table 2016-087326

However, the technique disclosed in Patent Document 1 specializes in evaluating the circulatory state of peripheral parts such as fingertips by making the area to be pressed and the area to be measured the same, and is useful for diagnosing PAD. However, it did not provide objective measurement results. In addition, the technology disclosed in Patent Document 2 evaluates the circulatory system by comparing the blood refilling time when pressure is released from multiple sites, for example, the fingertips of the right hand and the fingertips of the left hand. and did not provide objective measurement results for the diagnosis of PAD. Furthermore, when the techniques disclosed in Patent Literatures 1 and 2 are to be implemented as an apparatus, the configuration is complicated and the cost is high.

The present invention has been made in view of these circumstances in the above-mentioned background, and includes the anatomical control areas of the anterior tibial system, the posterior tibial system, and the peroneal artery system for the diagnosis of PAD. Accordingly, it is an object of the present invention to provide a blood flow evaluation apparatus that enables more specific prediction of diseases of the central vascular system and that has a simple and inexpensive configuration.

To achieve the above object, the present invention is a blood flow evaluation apparatus capable of more specifically predicting diseases of the central vascular system. One aspect of the present invention is a pressurizing means attached to the ankle for avascularization and release, an imaging means for imaging a toe extending from the pressurizing means to the toe side in chromatic colors, and the An analysis means for recording the images acquired by the imaging means in chronological order and performing image processing for normalizing the acquired images to a color space; and means. Then, the estimating means displays a temporal change in chromaticity coordinate values relating to a specific color specification of the image after the pressurizing means is released, calculates the amount of temporal change, and calculates the temporal change. When the amount becomes negative, it is assumed that the recovery state has occurred, and the recovery time from the release to the recovery state is measured.

This configuration is intended for the toes where peripheral arterial disease is likely to manifest. A pressurization means such as a tourniquet is attached to the patient's ankle, and the blood flow in the toe is changed by performing avascularization and release. Since this change in blood flow is expressed as a color change on the surface of the toe, the toe is imaged in chromatic colors by imaging means such as a video camera. A captured moving image is subjected to normalization processing in the color space in order to digitize the image data. Normalization of the color space means, for example, digitizing the color between 0 and 1 with the distance between white and black at which the color difference is maximum as MAX. In order to stabilize the condition of the image to be captured, the imaging means may be configured to include the light-emitting element and the light-receiving element.

For example, the digitized color coordinate values are binarized by setting a threshold for a specific color specification, and the area of an area including coordinates equal to or greater than the threshold is calculated, or the total coordinate value over the entire imaging area is calculated. By doing so, the temporal change amount of the surface color change of the toe portion is digitized and calculated. When the blood is staunched and then released, the color of the surface of the toe suddenly increases from whitish to a normal surface color. It is assumed that the recovery state is reached when the slope of the target change becomes negative (meaning the aforementioned decrease in area, decrease in total coordinate value, etc.).

According to the present invention, the blood flow is changed by wrapping it around the ankle using the pressurizing means, recording it with the imaging means, performing image processing with the analyzing means, and starting from the process of releasing the hemostasis from the blood flow. It is possible to visualize the stagnant part. In this way, blood flow can be visualized, and by supporting the actions of confirming and selecting amputation points, it is possible to make diagnoses that lead to surgery with fewer errors and less burden on the patient, regardless of the skill level of the doctor. do. In addition, it has a simple configuration and can be used by healthy people for daily health management by installing a dedicated application on a smartphone with a low-cost configuration depending on the accuracy and the like.

In the above configuration, the amount of change over time is positive and the time from the opening when the increment in a predetermined time segment decreases is measured, and the time is subtracted from the recovery time to The expansive reaction time can be calculated.

In the ABI examination, the inventors found that in the process from the release of avascularization to recovery, the blood vessels first expanded rapidly, then expanded further, although the rate of expansion slowed down, and then recovered to normal vessels. . In this way, it is thought that the increase in blood flow in peripheral arteries changes in roughly two stages. Assuming that rapid spread after release is Phase 1 and subsequent spread is Phase 2, the duration of Phase 2 is presumed to indicate the active state of hemodynamics in the living body from the findings of the inventors. That is, if the duration of phase 2 is short, it may be determined that the patient is in a healthy state, and conversely, if the duration of phase 2 is long, blood flow is stagnant and peripheral blood vessels may be necrotic. Gender can also be assumed.

According to the above configuration, it is possible to visualize the state of blood flow to support the diagnosis of PAD and to support the diagnosis of the health state of peripheral defects. Furthermore, by assisting in the indication of the cutting point, it is possible to perform surgery with less burden on the patient than in the past.

In the combat configuration, the estimating means can generate a signal when the temporal variation is less than or equal to a predetermined value from the release to the recovery state.

As described above, the increase in the flow rate of the blood flow changes in two stages, following rapid spread after release (Phase 1) and subsequent spread (Phase 2). It is estimated that the timing of transition from phase 1 to phase 2 is when the amount of change over time becomes equal to or less than a predetermined value set in advance. According to the above configuration, the timing of this transition can be recorded, and can be used as digital time to assist in determining the blood flow evaluation.

In the above configuration, the toe portion may include the instep and/or the sole of the foot.

Changes in blood flow can be observed on the sole of the foot, which is the surface of the toe, or the instep, which is the surface of the toe. Compared to the sole and the instep, blood flow is greater in the sole, but it is necessary to observe both the sole and the instep to assist in making more accurate decisions. However, when observing both at the same time, a plurality of imaging devices are required, and when observing the soles of the feet, it is necessary to put the feet on and a table to fix them, etc., so the size of the device is large. problems such as increased cost or higher cost. However, even if it is the sole or the top of the foot, even if the evaluation accuracy is lower than when both are observed at the same time, it is possible to perform observations that support blood flow evaluation. Therefore, according to the above configuration, the observation is made at a site including the sole of the foot, which is the surface of the toe portion, or the instep, which is the surface of the toe, or both.

In the above configuration, the color space may be an RGB color space, and the specific color specification may be R.

According to the configuration, the RGB color space can be applied as an example of the color space. Processing in the RGB color space, for example, is as follows: 1) Obtain the maximum and minimum values from changes in the luminance value of only the R value and perform normalization and inversion processing; 2) Then, process the R value/(G value + B value). and perform normalization inversion processing with the acquired value of relative (perceived by humans) “redness (redness)”. The RGB color space is a color system in which the primary colors are R (red, 700 nm), G (green, 546.1 nm), and B (blue, 435.8 nm), and colors can be quantified by coordinates. As described above, by setting a threshold for a specific color specification and binarizing, calculating the area of a region containing coordinates equal to or higher than the threshold, or calculating the sum of coordinate values over the entire imaging region, The amount of temporal change in color change on the surface of the toe can be digitized and calculated. Needless to say, any color space that can be recorded as a color profile (RGBA, YCbCr, CMYK, Lab color, etc.) can be applied as the color space without being limited to the RGB color space.

In the configuration, the color space may be the HSV color space, and the specific color specification may be S.

The HSV color space is a color space consisting of three components: Hue, Saturation/Chroma, and Value/Lightness/Brightness. show. According to the above configuration, the image can be defined into the evaluation area and the background area by binarizing the image using the saturation (S) in the HSV color space. Therefore, it is possible to analyze the evaluation area using the RGB color space or the like without being affected by disturbances due to colors or light outside the evaluation area. Defining the background region using the saturation (S) may be performed at the initial stage of observation, and after that, analysis may be performed based on a color space such as RGB based on the demarcated evaluation region.

For the diagnosis of PAD, the present invention includes the anatomical control areas of the anterior tibial system, the posterior tibial system, and the peroneal artery system, making it possible to more specifically predict diseases of the central vascular system. A blood flow evaluation device can be provided.

1 is an overall configuration diagram according to an embodiment of the present invention; FIG. 1 is a block configuration diagram according to one embodiment of the present invention; FIG. It is an example (health condition) of the blood flow evaluation which concerns on one Embodiment of this invention. 1 is an example of blood flow assessment (PAM) according to one embodiment of the present invention; It is a figure showing the situation of measurement concerning one embodiment of the present invention.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. FIG. FIG. 1 is an overall configuration diagram according to one embodiment of the present invention. FIG. 2 is a block configuration diagram according to one embodiment of the present invention. FIG. 3 is an example of blood flow evaluation (health condition) according to one embodiment of the present invention. In the following description, it may be assumed that configurations denoted by the same reference numerals in different drawings are the same, and description thereof may be omitted.

The blood flow evaluation apparatus according to the present invention comprises pressurizing means attached to the ankle for avascularization and release, and imaging means for imaging the toe extending from the pressurizing means to the toe side in chromatic colors. an analysis means for performing image processing for recording the images acquired by the imaging means in chronological order and normalizing the acquired images to a color space; estimating means for estimating, wherein the estimating means displays the temporal change in the chromaticity coordinate value related to the specific color specification of the image after the pressure means is released, and calculates the amount of temporal change; Any specific mode can be used as long as it is configured to calculate the amount of change over time, estimate that the state has transitioned to the recovery state when the amount of change with time becomes negative, and measure the recovery time from the release to the recovery state. It doesn't matter if there is.

<Description of the device>
Referring to FIGS. 1 and 2, a blood flow evaluation device 100 according to an embodiment of the present invention is attached to an ankle 10, and includes pressurizing means 110 for avascularization and release, and pressure means 110 for toe pressure. Imaging means 120, 125 for imaging the toe part 20 extending to the 22 side in chromatic colors, recording the images acquired by the imaging means 120, 125 in time series, and normalizing the acquired images in a color space. It is provided with analysis means 130 for performing image processing and estimation means 150 for estimating the state of blood flow in the leg using the result of image processing. Further, a display unit 160 for displaying the result estimated by the estimation means 150 and a notification unit 170 for generating a signal such as sound or light according to the result may be provided.

The pressurizing means 110 includes a rubber bag-like cuff similar to a tourniquet for an arm, or a compression band called a manchette, which is wrapped around the ankle 10 and pumped with air by a pump or the like (not shown) to increase the pressure, thereby increasing the pressure on the foot. The part 20 is avascularized. The pressure to be raised is set according to the condition of the subject, such as the color tone and pulse of the toe 20 .

The imaging means 120 and 125 include an imaging means 120 for imaging the instep 24 of the toe portion 20 in the direction of the toes 22 in chromatic colors and an imaging means 125 for imaging the sole 26 in chromatic colors. Either one of these may be provided, or both of them may be provided. Imaging means 120 and 125 continuously capture images from pressurization of pressurizing means 110 to release of pressurizing means 110 and recovery of blood flow, and send captured image data to analyzing means 130 .

Imaging elements such as a video camera and a CCD image sensor, which are equipment/devices capable of imaging in chromatic colors, can be applied to the imaging means 120 and 125 . Light rays detected by the imaging means 120 and 125 are visible light for color space analysis. However, infrared light or the like may be selected according to the imaging situation. For example, by applying infrared light, especially near-infrared light, it is possible to acquire an image for aiming even in a scene with few external light sources. In order to stabilize the condition of the image to be captured, the image capturing means may include the light receiving elements 122 and 127 for image capturing as well as the light emitting elements 121 and 126 such as lights for illuminating the object.

The analyzing means 130 and the estimating means 150 are each composed of a microcomputer, and include a processor CPU that performs calculations, a ROM that stores control programs and various data lists, tables, maps, and other items necessary for calculation and recording, and It has a RAM that temporarily stores the results of calculations by the CPU. The analyzing means 130 and the estimating means 150 have a nonvolatile memory, and store necessary data and the like in this nonvolatile memory. The non-volatile memory can be composed of an EEPROM, which is a rewritable ROM, or a RAM with a backup function that retains memory by supplying a retention current even when the power is turned off. Although the analyzing means 130 and the estimating means 150 will be described below as separate means, they may be configured to have both functions as one microcomputer.

The analysis means 130 records the images acquired by the imaging means 120 and 125 (light receiving elements 122 and 127) in time series, and performs image processing for normalizing the acquired images in a color space. The normalizing image processing digitizes captured image data, for example, digitizing the color between 0 and 1 with the distance between white and black having the maximum color difference as MAX. By normalizing the image data, it is possible to make the image data easier to use for deformation, comparison, calculation, etc. based on a certain rule.

The analysis means 130 includes, for example, a color space conversion section 132 that defines data sent from the light receiving elements 122 and 127 in a predetermined area, and an evaluation image generation section 138 that generates an image to be evaluated based on the defined image. You may comprise.

The color space conversion unit 132 binarizes the image using, for example, the saturation (S) of the HSV color space, so that the evaluation area of the toe part 20 for blood flow evaluation of the image and the toe part 20 are converted into It can be configured to include a background area definition section 134 that defines a background area in which the surroundings of the display are reflected. By making such a definition, it is possible to perform subsequent color space analysis on the surface of the toe 20 without being affected by disturbances due to colors and lights outside the evaluation area. Defining the background region using the saturation (S) may be performed at the initial stage of observation, and after that, analysis may be performed based on a color space such as RGB based on the demarcated evaluation region. Moreover, in the case where the influence of disturbance, light scattering, etc. on the evaluation is small, the background region defining section 134 may not be provided.

The color space conversion unit 132 may include, for example, an evaluation area definition unit 136 that normalizes the image from which the background has been removed by the background area definition unit 134 into the RGB color space. Processing by the RGB color space focuses on the R value because the "redness" of the blood flow is expressed, obtains the change in luminance value in time series only for the R value, and from the maximum and minimum values, Colors between 0 and 1 or when expressed with 8-bit gradation are digitized from 0 to 255 (normalization). Red with maximum brightness can be represented as (1,0,0) when 0 to 1, and (255,0,0) when 0 to 255. Needless to say, as described above, any color space (RGBA, YCbCr, CMYK, Lab color, etc.) that can be recorded as a color profile can be applied as a color space without being limited to the RGB color space. Furthermore, by combining the respective color spaces and performing calculations, it is also possible to make the evaluation site more obvious.

In addition, if the state of blood flow can be revealed in the processing using the RGB color space, not only red (R value) but also other colors such as green, blue, black, and white can be appropriately selected. You can also

For example, the evaluation image generation unit 138 sets an appropriate threshold value for the R value, binarizes it, and performs inversion processing, thereby clarifying the range to be evaluated. In addition, when the boundary between "redness" and other colors is not clear, each value is totaled for each dot of the image, etc., and an evaluation image is generated that shows the overall change in "redness". A unit 138 may be configured. The image data processed by the evaluation image generator 138 is then sent to the estimation means 150 .

Before describing the estimating means 150, an example of blood flow evaluation in a healthy state will be described with reference to FIG. The vertical axis in FIG. 3 represents the R value of the image data processed by the evaluation image generation unit 138, and the horizontal axis represents time. The R value changes stepwise with the passage of time, and each phase (stage) will be explained over time.

The "normal state" phase is the image data R value of the toe portion 20 before the pressurizing means 110 is attached to the ankle 10, and remains at the same value. Then, in the event of "start of avascularization", the pressurizing means 110 is attached to the ankle 10, and the phase shifts to "avascularization". In the "avascularization" phase, since blood does not flow to the toe 20, the R value decreases as the "redness" gradually decreases.

The pressurizing means 110 of the ankle 10 is released in the event of "release of avascularization", the blood flow in the toe 20 is restored, and the "redness" of the toe 20 increases due to the "release of avascularization". , a sharp increase in the R value is observed. As described above, in the ABI test, the inventors found that in the process from the release of avascularization to recovery, the blood vessels first expanded rapidly, then expanded further although the speed of expansion slowed down, and then recovered to normal blood vessels. I discovered. In this way, the increase in blood flow in peripheral arteries is considered to transition in roughly two stages, and a rapid increase in the R value is observed in "Phase 1", which represents rapid expansion of blood vessels.

Next, the rise in R value over time is moderated somewhat, ie, "Phase 2" is observed in which normal blood vessels are restored. As described above, from the findings of the inventors, it is estimated that the duration of Phase 2 indicates the active state of hemodynamics in the living body. That is, if the duration of phase 2 is short, it may be determined that the patient is in a healthy state, and conversely, if the duration of phase 2 is long, blood flow is stagnant and peripheral blood vessels may be necrotic. Gender can also be assumed.

When "Phase 2" ends, the recovery process to "normal" is entered, the R value decreases, and the blood flow evaluation ends.

The estimating means 150 determines the transition from “phase 2” to “recovery” after the “opening of avascularization” event, that is, the slope of the amount of change over time for the R value (“redness”) becomes negative (described above The recovery time T2N is calculated by estimating the recovery state at the point in time (meaning a decrease in area, a decrease in the total coordinate value, etc.). Furthermore, the estimating means 150 determines that the transition from "Phase 1" to "Phase 2" after the event of "Astasis release", the amount of temporal change in the R value is positive, and in a predetermined time segment set in advance The vasodilator response time T1N is calculated by measuring the time from the event of "cleavage of the blood vessels" when the increment of T1N decreases and subtracting this time from the recovery time T2N. The reason why the predetermined time interval is provided is that, for example, when the estimated time is too short compared to the vasodilator response time T1N assumed in a healthy state, the surrounding light/color This is because there is a possibility that there is a problem in the setting of the environment or color space, and that it is caused by a spike-like disturbance or the like.

The display unit 160 is a general display monitor, and the time-series transition of the R value analyzed by the analysis means 130 as shown in FIG. Reaction time T1N is displayed.

The notification unit 170 notifies each event and phase shown in FIG. 3 by sound or image, so that the subject can confirm the progress of the examination. In addition, based on the estimation result obtained by the estimation means 150, as a support for PAD diagnosis evaluation, thresholds for the recovery time T2N and the vasodilation positive reaction time T1N may be set in advance, and a notification may be given when these thresholds are exceeded. can.

<Example of blood flow evaluation>
An example of blood flow evaluation according to an embodiment of the present invention will be described below with reference to FIGS. 3 to 5. FIG. FIG. 4 is an example of blood flow assessment (PAM) according to one embodiment of the present invention. FIG. 5 is a diagram showing the situation of measurement according to one embodiment of the present invention. Note that the events and phases of the example of blood flow evaluation in a healthy state in FIG. 3 have been described above, and redundant descriptions will be omitted.

First, referring to FIG. 5, the ankle 10 is vertically arranged with the pressurizing means 110 during avascularization and avascularization release, respectively. The image on the left is an image measured with general visible light, and the image on the right is processed in the RGB color space focusing on the R value. , and the minimum value, 0 to 1 or 0 to 255 when expressing the color in between with gradation of 8 bits (normalization), which is further subjected to inversion processing. In this example, there is no background region definition unit 134 for defining an image into an evaluation region of the toe 20 for blood flow evaluation and a background region in which the surroundings of the toe 20 are reflected. .

As shown in FIG. 5, the surface of the instep 24 of the toe portion 20 has a slightly whitish color when looking at the measurement image during venous venous. The measurement image (reversal processing) is obtained by normalizing the measurement image with respect to the R value and further performing binarization and reversal processing using a predetermined threshold value. Looking at this measurement image, the color is dark, indicating that there is almost no "redness".

Next, looking at the evaluation image (reversal processing) obtained by performing the same image processing on the same measurement image of open avascularization in FIG. 5, it is shown that the area of the “reddish” portion is increased. In this way, the state of color change of the toe portion 20 is revealed.

In the embodiment shown in FIG. 5, the health status and PAM blood flow assessment results are shown in FIGS. 3 and 4, respectively. Comparing FIG. 3 and FIG. 4, recovery time T2P and vasodilation normal response time T1P are longer than recovery time T2N and vasodilation normal response time T1N.

The duration of Phase 2 is the recovery time T2P minus the vasodilation correct time T1P. If the duration of phase 2 is long, it is presumed that lipid deposits are formed in the blood vessels, narrowing the arteries, restricting blood flow, and possibly necrosis of the peripheral blood vessels. can do.

Thus, in this example of blood flow evaluation, it is possible to assist in determining which part of the peripheral blood vessel is necrotic and should be cut and treated, and to prevent the cut part from being defined larger than necessary. can.

In the prior art, changes in the nail plate are observed, and only changes in the periphery of the periphery are observed. On the other hand, according to the present invention, since the ankle 10, which is more central, is avascularized by the pressurizing means 110, it is possible to see a wider range of parts such as the dorsum and the sole, and the anatomical anterior tibia system and posterior tibia system. It becomes possible to support the evaluation of the tibial system and fibular artery system. That is, it becomes possible to more specifically predict troubles in the central vascular system.

In actual clinical practice, it is important to determine which of these three systems (anterior tibia, posterior tibia, and peroneal artery) is the problem in the lower leg. The posterior tibial and fibular artery systems have anatomically determined regions. Therefore, by checking these points with the blood flow evaluation device according to the present invention, more detailed evaluation becomes possible. On the other hand, in the nail plate disclosed in the prior art, the information is in the form of a mixture of any peripheral or some of the anterior tibial system, posterior tibial system, and peroneal artery system, so there is a possibility that the information will be quite ambiguous. be.

As described above, the present invention includes the anatomical control areas of the anterior tibial system, the posterior tibial system, and the peroneal artery system for the diagnosis of PAD, and more specifically the central vascular system. It is possible to provide a blood flow evaluation device that can predict the disease of. It can also be used for health management of able-bodied persons by using a simple configuration with slightly reduced accuracy, such as a smartphone application.

DESCRIPTION OF SYMBOLS 10... Ankle 20... Toe part 22... Toe 24... Instep 26... Sole 100... Blood-flow evaluation apparatus 110... Pressurization means 120, 125... Imaging means 121, 126 Light-emitting elements 122, 127 Light-receiving elements 130 Analyzing means 132 Color space conversion section 134 Background area defining section 136 Evaluation area defining section 138 ... Evaluation image generation section 150 ... Estimation means 160 ... Display section 170 ... Notification section

Claims (4)

a pressurization means attached to the ankle for avascularization and release;
imaging means for imaging the toe portion extending from the pressurizing means toward the toe side in a chromatic color;
an analysis means for recording the images acquired by the imaging means in time series and performing image processing for normalizing the acquired images to an RGB color space;
estimating means for estimating the blood flow state of the leg using the image processing result;
The estimation means is
displaying a temporal change in a chromaticity coordinate value related to R in the RGB color space as a specific color specification of the image after the pressurizing means is released, and calculating the amount of temporal change;
When the amount of change over time becomes negative, it is estimated that the surface color of the toe part has changed from a whitish state to a recovery state in which the surface color increases to reddish and returns to a normal surface color ,
Measuring the time from the opening to the recovery state as recovery time,
Measure the time from the release when the temporal change amount is positive and the increment in a predetermined time interval decreases, and subtract the time from the recovery time to obtain the vasodilator response time A blood flow evaluation device , characterized in that it calculates 2. The blood vessel according to claim 1 , wherein said estimating means generates a signal when said amount of change over time is equal to or less than a predetermined value from said opening to said recovery state. flow evaluator. 3. The blood flow evaluation device according to claim 1 , wherein the toe portion includes the instep of the foot. The blood flow evaluation device according to any one of claims 1 to 3 , wherein the toe portion includes the sole of the foot.

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