Method and system for measuring the flow rate and / or flow rate of urinated urine

Abstract

To provide a method and a system for measuring a flow velocity and / or a flow rate of urine, capable of being easily performed by a patient himself / herself, and excellent in measurement accuracy.SOLUTION: A method for measuring a flow velocity and / or a flow rate of discharged urine, includes recording an image of the discharged urine, determining an interval of axis-switching in the recorded image of the urine, and calculating one or both of the flow velocity and the flow rate from the determined interval of the axis-switching. A system for measuring a flow velocity and / or a flow rate of discharged urine, includes means for recording an image of the discharged urine, means for determining an interval of axis-switching in the recorded image of the urine, and means for calculating one or both of the flow velocity and the flow rate from the determined interval of the axis-switching.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method and system for measuring the flow rate and / or flow rate of urine being excreted. [Background technology]

[0002] Uroflowmetry is essential for the diagnosis, treatment, and monitoring of urinary disorders caused by conditions such as benign prostatic hyperplasia, overactive bladder, and neurogenic bladder. In medical institutions, it is common to use a device with a cup placed under a portable commode to record urine volume and flow rate. However, because the environment is different from a toilet used at home, patients often become anxious or have difficulty timing their urination, making accurate measurements difficult. Furthermore, while multiple measurements in a normal environment are ideal, performing these methods at home is not practical due to cost and hygiene concerns.

[0003] To overcome these problems, several simple methods for measuring uroflowmetry have been proposed and developed. These include a non-contact uroflowmetry method using an airborne ultrasound Doppler system (Patent Document 1), a method for determining the flow rate by analyzing images taken during urination (Patent Document 2), a non-contact uroflowmetry method using a temperature sensor (Patent Document 3), a method using a waterwheel-type uroflow sensor (Patent Document 4), and a method using multiple biosensors (Patent Documents 5 and 6). Although the usefulness of each method has been demonstrated, none have been completed as a system that patients can easily record on a daily basis.

[0004] One convenient way to record urine flow on a daily basis is through an application that records the sound of urination with a smartphone and reconstructs the urination pattern from the strength of the sound (BE Technologies, MenHealth®). This is a groundbreaking method that places almost no burden on the patient. However, it has drawbacks, such as requiring the liquid level at which the urine lands, and the fact that the measurement accuracy may be considerably lower in cases of "weakened urine flow," one of the most important abnormalities among urinary disorders, because the sound becomes quieter. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2013-034548 [Patent Document 2] Japanese Patent Publication No. 2018-109285 [Patent Document 3] Japanese Patent Publication No. 2015-178764 [Patent Document 4] Japanese Patent Publication No. 2020-101381 [Patent Document 5] Japanese Patent Publication No. 2021-060221 [Patent Document 6] Japanese Patent Publication No. 2021-018211 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] Although several new methods have been proposed to replace the standard methods used in medical institutions, a method and device for measuring urine flow rate and / or flow rate that is non-contact with urine, offering superior hygiene, high measurement accuracy suitable for clinical use, and easily performed by patients themselves at home, has yet to be put into practical use.

[0007] The present invention aims to provide a method and system for measuring urine flow rate and / or flow rate that can be easily performed by the patient themselves without contact and offers excellent measurement accuracy. [Means for solving the problem]

[0008] The present invention is as follows: [1] Recording images of urine being excreted, To determine the interval of axis switching in the recorded urine image, and This includes calculating one or both of the urine flow velocity and flow rate from the determined axis switching interval. A method for measuring the flow rate and / or flow rate of urine being excreted. [2] The method according to [1], wherein the image of the urine is a video or a still image. [3] The still image is a series of still images taken in rapid succession, as described in [2]. [4] The method according to any one of [1] to [3], wherein the recorded urine image is transferred to another location, and the axis switching interval is determined from the transferred image at the other location. [5] The method according to any one of items [1] to [4], comprising transferring the determined axis switching interval to another location, and calculating one or both of the urine flow velocity and flow rate from the axis switching interval transferred at the other location. [6] The method according to any one of the items in [1] to [5], further comprising transferring one or both of the calculated urine flow rate and flow rate to another location. [7] The method of any one of the items [1] to [6], further comprising displaying one or both of the calculated urine flow rate and flow rate. [8] A means for recording images of urine being excreted. A means for determining the interval of axis switching in an image of recorded urine, and The means include for calculating one or both of the urine flow velocity and flow rate from the determined axis switching interval, A system for measuring the flow rate and / or flow rate of urine being excreted. [9] The system described in [8], wherein smart glasses are a means for recording images of urine being excreted.

[10] The system according to [8] or [9], wherein a smartphone is used to calculate one or both of the urine flow rate and flow rate from the interval of axis switching.

[11] The system according to any one of [8] to

[10] , further comprising means for recording an image of urinating urine, means for determining the interval of axis switching, and means for transferring the image of the urine.

[12] The system according to any one of [8] to

[11] , further comprising means for transferring the axis switching interval from means for obtaining the axis switching interval to means for calculating one or both of the urine flow rate and the urine flow volume.

[13] <0OO0091>The system according to any one of [8] to

[12] , wherein the means for calculating the urine flow rate is a calculating means installed in a medical institution.

[14] The system according to any one of [8] to

[13] , further comprising means for displaying one or both of the calculated urine flow rate and the urine flow volume, or means for recording one or both of the calculated urine flow rate and the urine flow volume. [Effect of the Invention] <OO00096>

[0009] ] According to the present invention, it is possible to provide a method and a system for measuring the urine flow rate and / or the urine flow volume, which can be easily performed by the patient himself / herself without contact and have excellent measurement accuracy. [Brief Description of the Drawings]

[0010] [Figure 1] Shows a schematic explanatory diagram of the analysis system used in the examples. [Figure 2] Shows an example of a free interface by the VOF method used in the examples. [Figure 3] Shows an example of the outflow conditions. [Figure 4] Shows the state of the liquid flowing out from the nozzle. [Figure 5] Shows a measurement example of the position (twisted position) L of the axis switching. [Figure 6] Shows the relationship between the position (twisted position) of the axis switching and the flow volume. [Mode for Carrying Out the Invention]

[0011] [Method for Measuring Urine Flow Rate and / or Urine Flow Volume] The present invention records an image of urine being excreted. To determine the interval of axis switching in the recorded urine image, and This includes calculating one or both of the urine flow velocity and flow rate from the determined axis switching interval. This relates to a method for measuring the flow rate and / or flow rate of urine being excreted.

[0012] The method of the present invention applies the axis switching phenomenon, which is one of the interfacial instability phenomena of fluids.

[0013] The method of the present invention records images of urine being excreted. The images can be moving images or still images, and the still images can be a single still image or two or more consecutive still images. By using moving images or consecutive still images, it is possible to determine the time changes of either or both of the urination velocity and flow rate, and these time changes can be used to diagnose urination disorders.

[0014] There are no particular restrictions on the method of recording images of urinating urine, but any method that records with sufficient accuracy to recognize the interval between axis switching in the urinating urine is acceptable. The patient can record the images themselves, and this can be done, for example, by the patient wearing or holding an image recording device. There are no particular restrictions on the device used for image recording, and it can be, for example, smart glasses or a camera attached to a smartphone. For example, when using smart glasses, the patient can wear the smart glasses and record images non-contactually.

[0015] Next, the interval of axis switching in the recorded urine image is determined. Axis switching is a phenomenon in which, when liquid flows out of a nozzle with an elongated elliptical cross-section rather than a circular one, the major and minor axes of the elongated elliptical liquid column cross-section shown immediately after flow are swapped, and a jet with a twisted rod shape is observed (see Rayleigh, L., “On the Capillary Phenomena of Jets,” Proc. R. Soc. London, 21, 71-97, (1879)). Since the shape of the tip of the urethra is generally elongated elliptical, axis switching also occurs in the urine being excreted. The interval of axis switching in the recorded urine image can be determined using existing image analysis methods. In image analysis methods, the image is binarized to extract the outline of the urine, the location of axis switching is identified, and the interval of axis switching can be determined from its length.

[0016] The axis switching interval can be determined on the same device used for image recording, or it can be determined by transferring the recorded urine image to another location and then determining the axis switching interval from the transferred image. For example, images recorded with smart glasses can be transferred to a device such as a smartphone, and the axis switching interval can be determined on the device after the transfer.

[0017] Calculate either the urine flow velocity or flow rate from the determined axis switching interval. Flow velocity is the length per unit time and is expressed in units such as mm / second or cm / second. Flow rate is the volume per unit time and is expressed in units such as cm. 3The flow rate is displayed in units such as / second and mL / second. The flow rate is calculated based on the axis switching interval. There is a correlation between the axis switching interval and the flow rate and flow rate, and by recording the time-series change of this interval, the urine flow rate and flow rate can be calculated, respectively. The relationship between the axis switching interval formed by the liquid discharged from the outlet, which is assumed to be the cross-sectional area of ​​the urethra, and one or both of the fluid flow rate and flow rate can be determined in advance, and this relationship can be used to convert the measured axis switching interval into flow rate and flow rate. The relationship between the axis switching interval and the fluid flow rate and flow rate, which can be determined in advance, may be obtained by simulation or by using actual urine discharge. In the case of simulation, it is appropriate to select the liquid to be used considering the physical properties of urine, such as viscosity.

[0018] Since the urine flow rate is determined as the product of the urine flow velocity and the cross-sectional area of ​​the urethra, the flow velocity obtained by conversion from the axis switching interval can be converted to a flow rate according to the cross-sectional area of ​​the urethra to determine the flow rate of the urine being excreted. In this invention, the urine flow rate can be directly determined using the relationship between the axis switching interval and the urine flow rate, which is known in advance, or the relationship between the axis switching interval and the urine flow velocity can be used to determine the urine flow velocity from the axis switching interval, and then the urine flow rate can be determined from the determined flow velocity using the cross-sectional area of ​​the urethra being measured.

[0019] The calculation of either or both of the urine flow rate and flow rate from the axis switching interval can be performed, for example, using a patient's smartphone. Alternatively, the calculated axis switching interval can be transferred elsewhere, and at the destination, either or both of the urine flow rate and flow rate can be calculated from the transferred axis switching interval. For example, the axis switching interval obtained using a patient's smartphone can be transferred to a medical institution via the internet or other means, and at the medical institution, either or both of the urine flow rate and flow rate can be calculated from the axis switching interval.

[0020] The patient's smartphone or other device can be used to calculate either the urine flow rate or flow rate based on the axis switching interval, and the calculated urine flow rate and / or flow rate can be transferred to another location, such as a medical institution.

[0021] The interval of axis switching and either or both of the determined urine flow rate and flow rate can be recorded on the patient's smartphone or at the medical institution. The information on the urine flow rate and flow rate of the urine transported to the medical institution can be used by healthcare professionals, for example, as data for telediagnosis.

[0022] The method of the present invention may further include displaying one or both of the calculated urine flow rate and flow rate. One or both of the urine flow rate and flow rate can be displayed on a device such as a smartphone or personal computer, or printed on paper media.

[0023] <Urine flow rate measurement system> The present invention provides means for recording images of urine being excreted. A means for determining the interval of axis switching in an image of recorded urine, and The means include for calculating one or both of the urine flow velocity and flow rate from the determined axis switching interval, It includes a system for measuring the flow rate and / or flow rate of urine being excreted.

[0024] There are no particular restrictions on the means used to record images of urinating urine, but any means that can record with sufficient accuracy to recognize the interval between axis switching in urinating urine is acceptable. For example, smart glasses can be used, but the system is not intended to be limited to them. Other examples include the camera attached to a smartphone. The recorded images can be videos or still images, and still images can be a single still image or two or more consecutive still images.

[0025] The means for recording images of urinating urine, the means for determining the interval of axis switching, and the means for transferring images of urine may be further included. There are no particular limitations on the means for transferring images of urine, and they may be, for example, the internet or Bluetooth®.

[0026] A means of determining the interval of axis switching in recorded urine images is a means of performing image analysis. Specifically, it is a means of performing an image analysis method that involves binarizing the image to extract the outline of the urine, identifying the location of axis switching, and determining the interval of axis switching from its length. As an example of a means of performing such image analysis, one can cite image analysis software developed and implemented for Android® smartphones, iPhones®, and Windows® PCs, which utilizes Intel's OpenCV (Open Source Computer Vision Library) as an image analysis library.

[0027] The means for calculating one or both of the urine flow velocity and flow rate from the determined axis switching interval may be a means having a calculation function that converts the axis switching interval to one or both of the urine flow velocity and flow rate based on the relationship between the axis switching interval and one or both of the flow velocity and flow rate, which is prepared separately, or a means having a calculation function that further calculates the flow rate from the determined flow velocity and the cross-sectional area of ​​the urethra. Such means may be software developed using standard libraries for Android® smartphones, iPhone®, and Windows® personal computers.

[0028] The system of the present invention may further include a device that displays one or both of the calculated urine flow rate and flow rate. The device for displaying the urine flow rate and flow rate may be, for example, a display on a device such as a smartphone or a personal computer. The system of the present invention may also include means for printing onto paper media or the like.

[0029] In the system of the present invention, a smartphone can be the device that calculates either or both the urine flow rate and flow rate from a recorded image of urine. Using this system, the patient can immediately check either or both of the urine flow rate and flow rate that they have measured.

[0030] The system of the present invention may further include a device for transferring one or both of the calculated urine flow rate and flow rate to another device or system. The other device or system may be the patient's own recording medium or a recording medium of a medical institution. The other device or system may be a device or system installed in a remote medical institution. There are no particular limitations on the means of transfer, and means such as the internet or Bluetooth® can be used.

[0031] The measurement system of the present invention, for example, consists of smart glasses and a smartphone. The system calculates the distance between axis switches from images taken by the patient themselves using the smart glasses, using an application stored on the smartphone, and can reproduce the patient's urination pattern. The reproduced urination pattern can then be transferred to a medical institution.

[0032] The measurement system of this invention is non-contact, making it highly hygienic. Furthermore, it can reproduce urination patterns with higher measurement accuracy compared to conventional non-contact methods. Moreover, by utilizing smart glasses and a smartphone, it can become a system that allows patients to record data daily without any hassle. [Examples]

[0033] The present invention will be described in more detail below based on examples. However, the examples are illustrative of the present invention and are not intended to limit the present invention to these examples.

[0034] Example 1 To verify the feasibility of a urine flow meter using axis switching as its measurement principle, numerical simulations were conducted in the following examples.

[0035] 1-1 Analysis system Figure 1 shows a schematic diagram of the analysis system. The coordinate system is the Cartesian coordinate system, with the base being the xz plane (depth direction is the x-axis) and the height direction being the y-axis. A rectangular domain with a width of 15 cm, a depth of 1.6 cm, and a height of 2 cm was set as the calculation domain. Air (viscosity μ) is contained within the domain. c , density ρ c It was assumed that the following conditions were met. A cylinder with an outer diameter of 10 mm and a length of 10 mm, simulating a nozzle, was placed on the left side of the domain, with its center 1.4 cm from the bottom of the domain and 0.8 cm from the front. A slit with a width w=1 mm and a height h=5 mm was provided as a liquid outlet. It was assumed that there was a flow channel inside the cylinder with the same shape as the slit. The viscosity μ of this flow channel at time 0 was assumed to be d , density ρ d The container is filled with a liquid simulating urine, and a velocity v is applied to the inlet (the surface at z=0). d A uniform flow was provided. Gravity was assumed to act downward (-y direction), but gravity was set to zero when measuring the torsional position of the axis switching, which will be described later.

[0036] We assume that air and liquids are incompressible Newtonian fluids. If we consider these fluids as a single fluid with different physical properties (single-fluid approximation) and describe the governing equations, the Navier-Stokes equations corresponding to the fluid's equation of motion and the continuity equation corresponding to the law of conservation of mass are as follows.

[0037]

number

[0038] Here, t is time, μ is density, u is the velocity vector, P is pressure, g is the gravitational acceleration vector, ρ is viscosity, σ is the interfacial tension coefficient, κ is curvature, and F is the VOF function (volume fraction of the liquid phase). The VOF function is a variable used in the VOF (Volume Of Fluid Method), which is one of the methods for expressing the gas-liquid interface [see Hirt, C.W. and Nichols, B.D., “Volume of Fluid (VOF) Method for the Dynamics of Free Boundaries,” Journal of Computational Physics, 39(1), 201 - 225 (1981); Mitsuhiro Ota et al., Numerical Simulation of Multiphase Flow, 31 - 63, Maruzen Publishing (2015)], and it is a function of position. The VOF method expresses the gas-liquid interface by setting the volume fraction (VOF function) F of each fluid for each computational cell. For example, assuming F = 0 for the gas phase, F = 1 for the liquid phase, and there is a gas-liquid interface when 0 < F < 1, it can be expressed as shown in Figure 2. The position of the interface can be determined by solving the transport equation (3) of the VOF function and using a specific algorithm to obtain the interface position.

[0039]

Number

[0040] The boundary conditions are as follows. The boundaries of the left side (z = 0 cm), right side (z = 15 cm), upper side (y = 2 cm), lower side (y = 0 cm), front side (x = 1.6 cm), and back side (x = 0 cm) of the domain excluding the cylindrical nozzle part are set as free conditions to let air or liquid with the same volume as the inflowing liquid flow out. The outer surface of the cylindrical nozzle and the inner surface of the flow path with a slit shape are given the condition of a wall without slip (no-slip condition). At the inlet of the slit-shaped flow path, a uniform velocity distribution with an average flow velocity v d is given. Here, v d is made a function of time to simulate the actual outflow of urine.

[0041] These governing equations were approximated using the finite volume method and solved using OpenFOAM (Open source Field Operation And Manipulation). OpenFOAM is a C++ toolbox for numerical analysis of continuum mechanics, including computational fluid dynamics, and for pre- and post-processing [see OpenFOAM Foundation, https: / / openfoam.org / , Open CAE Society (ed.), Numerical Analysis of Heat Transfer and Flow using OpenFOAM, Morikita Publishing (2016)]. The VOF method used in this example also utilizes an algorithm already implemented in OpenFOAM. The computational domain was uniformly divided into a structured grid (rectangular mesh), with a mesh count of 384,000 (32 × 40 × 300).

[0042] 1-2 Liquid Outflow Simulation Experiment Table 1 shows the physical properties of the fluids. The density and viscosity of air were taken at room temperature. The specific gravity and specific viscosity of urine from healthy individuals relative to water have been reported to be 1.003–1.030 and 1.037–1.142, respectively [6]. Although the density of urine is at most a few percent greater and its viscosity is about 10% greater than that of water, the hydrodynamic differences were considered to be negligible, and the physical properties of water at room temperature were used. For surface tension, considering that urine is a mixture, a value of about 70% of the surface tension of pure water (72 mN / m) was used. This is roughly in line with the reported surface tension values ​​of urine from healthy individuals, which are 48.2–65.1 mN / m [see Yosuke Ohara, "Studies on Urine Surface Tension and Surfactants in Urine," Journal of the Japan Medical University, 38(5), 216-224 (1971)].

[0043] [Table 1]

[0044] Figure 3 shows the outflow conditions from the slit. The discharge velocity was linearly increased to 4 m / s until time 1 s, then maintained at that velocity for 2 s, and then linearly decreased from time 3 s until the inflow stopped at 4 s. The discharge velocity can be converted to flow rate by equation (4), and since the slit width w = 1 mm and height h = 5 mm as the liquid outlet, the maximum flow velocity vd A flow rate of 4 m / s corresponds to a flow rate Q of 20 mL / s.

[0045]

Number

[0046] There are reports that the maximum urine flow rate in adult males is 20 - 25 mL / s [see Masaki Okochi, Latest Urology, 12 - 27, Asakura Shoten (1983)], and the set flow velocity and flow rate generally correspond to this range.

[0047] 1 - 3 Measurement of the position of axis switching Fig. 4 shows a side view of the liquid outflow obtained by simulation. A jet is generated from the outlet, and a torsional position due to axis switching can be seen near the outlet at time 0.5 s. At time 1.9 s, it can be seen that the torsional position has moved further forward from the outlet. In addition, secondary small fluctuations are observed on the liquid surface, and it is considered that the actual urine outflow state is almost reproduced.

[0048] Fig. 5 shows the measurement method of the position (torsional position) of axis switching. The torsional position was measured with the distance L from the outlet to the location where the torsional position occurred. Also, the gravity was set to zero to avoid the jet hanging downwards, ensuring the accuracy of the measured distance. From this measurement, the relationship between the flow velocity v d given as the inflow condition, L, and the flow rate Q can be obtained.

[0049] Fig. 6 shows the relationship between the measured torsional position L and the flow rate Q. It can be seen that there is a clear correlation between L and Q, and Q can be obtained by measuring L. The measured data could be correlated by the following equation.

[0050]

Number

[0051] 1 - 4 Numerical simulations were conducted for the development of a urine flow meter using axis switching as the measurement principle. The simulation, which simulated urine flow, applied interface tracking using the VOF method and directly solved the Navier-Stokes equation to reproduce the time change in the interface shape of the liquid ejected from a long, narrow slit. The point where axis switching occurs (twist position), where the long and short axes of the ejected jet cross-section are swapped, was measured from the simulation video, and the relationship between the twist position and the flow rate was investigated. As a result, a clear correlation was found between the twist position and the flow rate, and the correlation equation was derived. From these results, it became clear that measuring urine flow velocity using axis switching is feasible. [Industrial applicability]

[0052] The present invention is useful in the field relating to methods and systems for measuring the flow rate and / or flow rate of urine being excreted.

[0053] By using the measurement method and system of the present invention, a monitoring system connecting patients and medical institutions can be constructed. In this case, the only data extracted from the video recorded by the patient is the distance between axis switches, resulting in a low video processing load, and data processing can be easily performed on the patient's smartphone. Furthermore, the only information transmitted to the monitoring system is the urination pattern, which not only reduces the communication load but also minimizes the risk of the recorded video being leaked externally, making it extremely effective in protecting patient privacy.

[0054] Such monitoring systems require minimal effort from the patient and allow for the recording of urination patterns at every urination, regardless of location, every day. Furthermore, they enable detailed monitoring of the treatment progress for urinary disorders, and can capture previously unknown short-term changes in symptoms and diurnal variations in urinary disorders. Therefore, they are expected to contribute to the development of new diagnostic and treatment methods.

Claims

1. To record an image of urinated urine using an image recording device without contacting the urinated urine, To determine the interval of axis switching in the recorded urine image, and This includes calculating one or both of the urine flow velocity and flow rate from the determined axis switching interval. A method for measuring the flow rate and / or flow rate of urine being excreted.

2. The method according to claim 1, wherein the image of the urine is a video or a still image.

3. The method according to claim 2, wherein the still image is two or more consecutively taken still images.

4. The method according to claim 1, comprising transferring recorded urine images to another location and determining the axis switching interval from the transferred images at the other location.

5. The method according to claim 1, comprising transferring the determined axis switching interval to another location, and calculating one or both of the urine flow velocity and flow rate from the axis switching interval transferred at the other location.

6. The method according to claim 1, further comprising transferring one or both of the calculated urine flow rate and flow rate to another location.

7. The method according to claim 1, further comprising displaying one or both of the calculated urine flow rate and flow rate.

8. A means for recording images of urine being excreted. A means for determining the interval of axis switching in an image of recorded urine, and The means include for calculating one or both of the urine flow velocity and flow rate from the determined axis switching interval, A system for measuring the flow rate and / or flow rate of urine being excreted.

9. The system according to claim 8, wherein smart glasses are the means for recording an image of urine being excreted.

10. The system according to claim 8 or 9, wherein a smartphone is a means for calculating one or both of the urine flow rate and flow rate from the interval of axis switching.

11. The system according to claim 8, further comprising means for recording an image of urinating urine, means for determining the interval of axis switching, and means for transferring an image of urine.

12. The system according to claim 8, further comprising means for determining the axis switching interval, means for calculating one or both of the urine flow rate and flow rate, and means for transferring the axis switching interval.

13. The system according to claim 8, wherein the means for calculating the urine flow rate is a calculation means installed in a medical institution.

14. The system according to claim 8, further comprising means for displaying one or both of the calculated urine flow rate and flow rate, or means for recording one or both of the calculated urine flow rate and flow rate.

Images