Endoscope system for measuring blood flow velocity in gastrointestinal superficial small blood vessel

Abstract

The purpose of the present invention is to provide a means for measuring a blood flow velocity in a gastrointestinal superficial small blood vessel on a real-time basis.　Provided is an endoscope system for measuring a blood flow velocity in a gastrointestinal superficial small blood vessel, the endoscope system being provided with a magnifying endoscope and a unit for processing blood flow moving image data obtained in the magnifying endoscope, i.e., a blood flow moving image data processing unit, and the endoscope system being characterized in that (A) the magnifying endoscope captures a blood flow moving image of a gastrointestinal superficial small blood vessel and sends the blood flow moving image to the blood flow moving image data processing unit, and (B) the blood flow moving image data processing unit that has received the blood flow moving image performs the following data processes (B1) to (B5).　(B1) A process for disassembling the obtained blood flow moving image into frames; (B2) a process for comparing an image of a frame 1 with an image of a next frame 2 to remove a parallel shift component; (B3) a process for calculating a difference of a red component in the image from which the parallel shift component has been removed; (B4) a process for regionalizing a region for which the difference of the red component has been calculated; and (B5) a process for calculating a region size of the obtained region data.

Description

Endoscopic system for measuring blood flow velocity in the microvessels of the gastrointestinal tract

[0001] The present invention relates to an endoscope system for measuring blood flow velocity in microvessels in the surface layer of the digestive tract.

[0002] In recent years, advances in endoscopic equipment and technology have led to the establishment of a magnifying endoscopic diagnostic system, enabling qualitative diagnosis of gastrointestinal lesions based on images of the microvascular architecture and surface ultrastructure of the gastrointestinal surface. However, this is a static diagnostic system using still images. Magnifying endoscopy allows observation of blood flow (movement of red blood cells) in the microvessels of the surface, but the way in which blood flow varies in gastrointestinal lesions compared to normal mucosa has not been investigated to date. Dynamic endoscopic diagnosis of the vital functions of the gastrointestinal mucosa will provide a new evaluation method for the diagnosis and pathogenesis of various gastrointestinal lesions, including gastrointestinal cancer, and may lead to the diagnosis of lesions that were difficult to diagnose using previous static diagnostic systems, or lesions that were technically difficult to diagnose.

[0003] The present inventors have measured the blood flow velocity of the gastric superficial microvessels using a magnifying endoscope and have found and reported that the blood flow velocity of the gastric superficial microvessels is useful for qualitative diagnosis in the magnifying endoscopic diagnosis of early gastric cancer (Non-Patent Documents 1 to 4).

[0004] 97th Annual Meeting of the Japan Gastroenterological Society Endoscopy Society (JGES 2019) American College of Gastroenterology, October 25, 2019-October 30, 2019 28th Japan Gastroenterological Disorders Week (JDDW 2020) J Gastroenterol Hepatol. 2021;36(7):1927-1934. doi:10.1111 / jgh.15425.

[0005] However, the above-mentioned method for measuring blood flow velocity in microvessels is an inefficient method requiring post-mortem analysis, and a new means for measuring blood flow velocity in microvessels in the surface layer of the digestive tract in real time has been desired for practical use in clinical practice. Therefore, an object of the present invention is to provide an endoscopic system for measuring blood flow velocity in microvessels in the surface layer of the digestive tract in real time.

[0006] The inventors therefore investigated how to measure the blood flow velocity of the microvessels on the surface of the digestive tract in real time. They found that by adopting a method for measuring the blood flow velocity using software from magnified endoscopic video images and measuring the fluctuations in the red component, which indicates the movement of red blood cells in the blood flow video images during image processing, it was possible to measure the blood flow velocity of the microvessels on the surface of the digestive tract in real time, and thus completed the present invention.

[0007] That is, the present invention provides the following inventions [1] to

[16] . [1] An endoscopic system for measuring blood flow velocity in microvessels in the superficial layer of the digestive tract, comprising a magnifying endoscope and a processing unit for processing video blood flow data obtained by the magnifying endoscope, wherein: (A) the magnifying endoscope captures video blood flow in the microvessels in the superficial layer of the digestive tract and sends it to the video blood flow data processing unit; and (B) the video blood flow data processing unit, upon receiving the video blood flow, performs the following data processing steps (B1) to (B5): (B1) a process for decomposing the obtained video blood flow into frames, (B2) a process for comparing an image of frame 1 with an image of the following frame 2 and removing translation components, (B3) a process for calculating the difference in the red components of the images from which the translation components have been removed, (B4) a process for segmenting the area where the difference in the red components has been calculated, and (B5) a process for calculating the region size of the obtained region data. [2] The endoscopic system according to [1], wherein the blood flow video data is blood flow video data of microvessels in a region of the gastrointestinal surface suspected of having an abnormality, obtained by a magnifying endoscope. [3] The endoscopic system according to [2], further comprising a process for comparing the obtained blood flow velocity of the microvessels in the gastrointestinal surface with the blood flow velocity of normal microvessels in the gastrointestinal surface. [4] The endoscopic system according to any one of [1] to [3], wherein the process for removing the translation component is a process for detecting differences between frames caused by blood flow. [5] The endoscopic system according to any one of [1] to [4], wherein the process for calculating the difference in the red component is a process for detecting the movement of red blood cells. [6] The endoscopic system according to any one of [1] to [5], wherein the region generated by the regionalization is a region through which red blood cells passed between frame 1 and frame 2. [7] The endoscopic system according to any one of [1] to [6], wherein the calculation of the region size is a calculation for calculating the minor axis and major axis of the region. [8] An endoscope system according to any one of [1] to [7], which calculates the flow velocity of each region in frame 2 based on the region size and the time from frame 1 to frame 2.

[0008] [9] A method for measuring blood flow velocity in microvessels in the surface layer of the gastrointestinal tract, comprising the steps of: capturing a video of blood flow in the microvessels in the surface layer of the gastrointestinal tract using a magnifying endoscope; decomposing the obtained video of blood flow into frames; comparing an image of frame 1 with an image of the following frame 2 to remove translational components; calculating a difference in the red component of the image from which the translational components have been removed; segmenting the area where the difference in the red component has been calculated; and calculating a region size of the obtained region data.

[10] The method according to [9], wherein the video of blood flow is a video of blood flow in microvessels in a region of the surface layer of the gastrointestinal tract suspected of having an abnormality, obtained using a magnifying endoscope.

[11] The method according to

[10] , further comprising a step of comparing the obtained blood flow velocity in the microvessels in the surface layer of the gastrointestinal tract with the blood flow velocity of normal microvessels in the surface layer of the gastrointestinal tract.

[12] The method according to any of [9] to

[11] , wherein the step of removing the translational components is a step of detecting differences between frames caused by blood flow.

[13] The measurement method according to any one of [9] to

[12] , wherein the step of calculating the difference in the red component detects the movement of red blood cells.

[14] The measurement method according to any one of [9] to

[13] , wherein the region generated by the regionalization is a region through which red blood cells passed between frame 1 and frame 2.

[15] The measurement method according to any one of [9] to

[14] , wherein the calculation of the region size is a calculation of the minor axis and the major axis of the region.

[16] The measurement method according to any one of [9] to

[15] , wherein the flow velocity of each region in frame 2 is calculated from the region size and the time from frame 1 to frame 2.

[0009] According to the endoscopic system and method of the present invention, the blood flow velocity of the microvessels in the surface layer of the digestive tract can be measured in real time using a magnifying endoscope, thereby enabling early diagnosis and elucidation of the pathology of gastrointestinal neoplastic lesions, non-neoplastic lesions, inflammatory bowel disease, inflammatory diseases and functional diseases related to the digestive tract, allergic gastrointestinal diseases, and gastrointestinal blood flow abnormalities caused by lifestyle-related diseases other than gastrointestinal diseases.

[0010] This figure shows the flow for determining the blood flow velocity from frame 2 of an endoscopic video and frame 1 to frame 2 using the endoscopic system of the present invention. In the figure, the gray areas represent processing means, and the white areas represent data. This figure shows the removal of translation components in frames 1 and 2. This figure shows the difference in red components. This figure shows the results of ROC analysis of the blood flow velocity in early gastric cancer and the average blood flow velocity of normal microvessels in the superficial layer of the stomach.

[0011] One aspect of the present invention is an endoscopic system for measuring blood flow velocity in microvessels in the superficial layer of the digestive tract, comprising a magnifying endoscope and a processing unit for processing video blood flow data obtained by the magnifying endoscope, wherein: (A) the magnifying endoscope captures video blood flow in the microvessels in the superficial layer of the digestive tract and sends it to the video blood flow data processing unit; (B) the video blood flow data processing unit, upon receiving the video blood flow, performs the following data processing steps (B1) to (B5): (B1) a process for decomposing the obtained video blood flow into frames; (B2) a process for comparing an image of frame 1 with an image of the following frame 2 and removing translation components; (B3) a process for calculating the difference in the red components of the images from which the translation components have been removed; (B4) a process for segmenting the area where the difference in the red components has been calculated; and (B5) a process for calculating the region size of the obtained region data. Another aspect of the present invention is a method for measuring blood flow velocity in microvessels in the surface layer of the digestive tract in real time from capturing a moving image of the microvessels in the surface layer of the digestive tract, comprising the following steps (a) to (f): (a) capturing a moving image of blood flow in the microvessels in the surface layer of the digestive tract using a magnifying endoscope; (b) dividing the obtained moving image of blood flow into frames; (c) comparing an image of frame 1 with an image of the following frame 2 to remove translational components; (d) calculating a difference in the red component of the image from which the translational components have been removed; (e) segmenting the portion where the difference in the red component has been calculated; and (f) calculating a region size of the obtained region data. Furthermore, by performing a process or step of comparing the obtained blood flow velocity in the microvessels in the surface layer of the digestive tract with the blood flow velocity of normal microvessels in the surface layer of the digestive tract, it is possible to diagnose whether cancer or other conditions have occurred in the digestive tract.

[0012] In the system of the present invention, (A) the magnifying endoscope captures video images of blood flow in the microvessels in the surface layer of the digestive tract and sends the captured video image data to the blood flow video data processing unit, and in the method of the present invention, (a) the step of capturing video images of blood flow in the microvessels in the surface layer of the digestive tract using the magnifying endoscope are both processes performed by the magnifying endoscope. This magnifying endoscope may be any endoscope capable of measuring blood flow in microvessels. Commercially available magnifying endoscopes have a video capture function.

[0013] The data processing steps (B1) to (B5) in the system of the present invention are substantially the same as steps (b) to (f) in the method of the present invention, so each step of the method of the present invention will be explained below. An example of a specific processing flow is shown in Figure 1.

[0014] Step (a) of the present invention is a step of taking a video of blood flow in microvessels at a site of suspected abnormality in the surface layer of the digestive tract obtained by a magnifying endoscope. This magnifying endoscope may be any endoscope capable of measuring blood flow in microvessels. Commercially available magnifying endoscopes have a video capture function.

[0015] Steps (b) to (f) of the present invention can be performed in real time by a computer that receives a blood flow video obtained by a magnifying endoscope. Known software can be used as a framework for the image processing of the present invention. For example, OpenCV, dlib, etc. can be used. Furthermore, development languages ​​such as c / c++, Python, and JavaScript can be used.

[0016] Furthermore, when executing the image processing software, it is preferable to specify the following three arguments.

[0017]

[0018] Step (b) is a step of decomposing the obtained magnified endoscopic blood flow video into individual frames. In this step, a video file captured by the magnified endoscope to be analyzed is designated, and the video is decomposed into individual frames. In this step, as shown in FIG. 1 , the video image is decomposed into an image of frame 1, an image of frame 2, an image of frame 3, etc.

[0019] Step (c) is a step of comparing the image of frame 1 with the image of the next frame 2 to remove the translation component. This operation results in an image from which the translation component between the image of frame 1 and the image of frame 2 has been removed (see FIG. 1). This step detects the parts where differences occur between the image of frame 1 and the image of frame 2, i.e., the differences between the frames caused by blood flow (see FIG. 2).

[0020] Step (d) is a step of calculating the difference in the red component of the image from which the translation component has been removed. This step is a step of calculating the difference in the red component between the image of frame 1 and the image of frame 2, i.e., the difference between the frames caused by blood flow. Since the movement of the red component is the movement of red blood cells in the blood, the movement of red blood cells can be detected by calculating the difference in the red component. In this step, when calculating the red component difference between frames, it is preferable to set a red component threshold in advance so that pixels with a difference in the red component equal to or greater than this are determined to have a difference.

[0021] Step (e) is a step of dividing the portion where the difference in the red component is calculated into a region, and measuring the region through which the red blood cells passed between frame 1 and frame 2.

[0022] Step (f) is a step of calculating the region size of the obtained region data, in which the minor axis and major axis of the region size are measured.

[0023] The above steps allow the blood flow velocity of each region in frame 2 to be measured. Furthermore, as shown in Table 2, the blood flow velocity of each region in other frame images of the resulting video can also be measured. By comparing this blood flow velocity with the blood flow velocity of normal microvessels in the surface layer of the digestive tract, it is possible to diagnose whether a disease such as early-stage cancer is present in the surface layer of the digestive tract. The comparison of these blood flow velocities can also be performed by a computer that performs steps (b) to (f) above.

[0024] Examples of gastrointestinal diseases include the esophagus, stomach, duodenum, small intestine, large intestine, and rectum. Examples of gastrointestinal diseases include neoplastic lesions such as esophageal cancer, gastric cancer, duodenal cancer, colon cancer, and rectal cancer; non-neoplastic lesions such as gastric polyps and colon polyps; inflammatory bowel diseases such as ulcerative colitis and Crohn's disease; inflammatory and functional diseases such as esophagitis, gastritis, functional dyspepsia, irritable bowel syndrome, chronic constipation, diarrhea, and abnormal bowel movements; allergic gastrointestinal diseases; and abnormal gastrointestinal blood flow due to lifestyle-related diseases other than gastrointestinal diseases. For example, the blood flow velocity in early gastric cancer was statistically significantly slower and had a narrower range than the blood flow velocity in normal gastric superficial microvessels, even when considering intra-individual variability. Furthermore, ROC analysis of each mean revealed a cutoff value of 1.09 (sensitivity 90.3%, specificity 89.7%), as shown in Figure 4.

[0025] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0026] Example 1 Using Python as the development language and OpenCV as the image processing framework, a magnified endoscopic video of the gastric mucosa was processed according to the flow chart in Figure 1 by specifying the three arguments in Table 1. The magnified endoscopic video was captured using a LASEREO 7000 series (FUJIFILM) endoscope system and an EG-L600ZW7 (FUJIFILM) scope. As a result, the image in Figure 2 with the translation component removed was obtained, and the difference in the red component in Figure 3 was detected. Then, steps (b) to (f) enabled measurement of blood flow velocity from the blood flow video of the microvessels in the surface layer of the gastrointestinal tract obtained by magnifying endoscopy. Table 2 shows the region size in each frame and the measurement results of blood flow velocity in that region.

[0027]

[0028] It is more preferable to measure blood flow velocity in real time by using a PC on which the above-mentioned blood flow measurement software is installed and by using previously recorded endoscopic video.

Claims

1. An endoscope system for measuring blood flow velocity of microtubules in a superficial layer of the digestive tract, comprising a magnifying endoscope and a processing unit for processing video data of blood flow obtained by the magnifying endoscope, (A) the magnifying endoscope captures a video of blood flow in the microvessels in the surface layer of the digestive tract and sends it to the video of blood flow data processing unit; (B) An endoscope system for measuring blood flow velocity in microvessels in the surface layer of the digestive tract, characterized in that the blood flow video data processing unit that receives the blood flow video performs the following data processing (B1) to (B5). (B1) A process of decomposing the obtained blood flow video into individual frames; (B2) A process of comparing the image of frame 1 with the image of the next frame 2 to remove translation components; (B3) A process of calculating the difference in the red component of the image from which the translation component has been removed; (B4) A process of dividing the portion where the difference of the red component is calculated into a region; (B5) A process of calculating the area size of the obtained area data.

2. The endoscope system according to claim 1, wherein the blood flow video data is blood flow video data of microvessels in a region of the surface of the digestive tract suspected of having an abnormality, obtained by a magnifying endoscope.

3. 3. The endoscope system according to claim 2, further comprising a process for comparing the obtained blood flow velocity in the microvessels in the surface layer of the digestive tract with the blood flow velocity in normal microvessels in the surface layer of the digestive tract.

4. 3. The endoscope system according to claim 1, wherein the process of removing the translational component is a process of detecting differences between frames caused by blood flow.

5. 3. The endoscope system according to claim 1, wherein the process of calculating the difference in the red component detects movement of red blood cells.

6. 3. The endoscope system according to claim 1, wherein the region generated by the regionalization is a region through which red blood cells have passed between frame 1 and frame 2.

7. 3. The endoscope system according to claim 1, wherein the calculation of the region size is a calculation for calculating a minor axis and a major axis of the region.

8. 3. The endoscope system according to claim 1, wherein the flow velocity of each region in frame 2 is calculated based on the region size and the time from frame 1 to frame 2.

9. A method for measuring blood flow velocity in microvessels in the surface layer of the digestive tract, comprising: Taking a video of blood flow in the microvessels of the surface of the digestive tract using a magnifying endoscope; a step of decomposing the obtained blood flow video into frames; A step of comparing an image of frame 1 with an image of the next frame 2 and removing translation components; calculating the difference in the red component of the translation-removed image; A step of dividing the area where the difference of the red component is calculated into a region; A method for measuring blood flow velocity in microvessels in the surface layer of the digestive tract, comprising a step of calculating the region size of the obtained region data.

10. 10. The measuring method according to claim 9, wherein the blood flow video is a blood flow video of microvessels in a region of the surface of the digestive tract suspected of having an abnormality, obtained by a magnifying endoscope.

11. The method according to claim 10, further comprising a step of comparing the obtained blood flow velocity in the microvessels in the surface layer of the digestive tract with the blood flow velocity in normal microvessels in the surface layer of the digestive tract.

12. 11. The measurement method according to claim 9, wherein the step of removing the translation component is a step of detecting differences between frames caused by blood flow.

13. 11. The measurement method according to claim 9, wherein the step of calculating the difference in the red component detects the movement of red blood cells.

14. 11. The measurement method according to claim 9, wherein the region is determined based on the region through which red blood cells pass between frame 1 and frame 2.

15. 11. The measurement method according to claim 9, wherein the calculation of the region size is performed by calculating the minor axis and the major axis of the region.

16. 11. The measurement method according to claim 9, wherein the flow velocity of each region in frame 2 is calculated from the region size and the time from frame 1 to frame 2.