JP2017221543A - Intra-tissue fat detection system, intra-tissue fat measuring device, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intra-tissue fat detection system that can quantitatively grasp intra-tissue fat in a compact device structure.SOLUTION: An intra-tissue fat detection system 10 of the present invention includes: a pressing deformation measuring device 12 for pressing a living body soft tissue with a fat component mixed therein by a predetermined force, and measuring the magnitude of the pressing force at that time and a deformation amount of the region of the pressed living body soft tissue; and an intra-tissue fat measuring device 13 for finding an intra-tissue body fat amount corresponding to the quantity of the fat component, based on measurement results at the pressing deformation measuring device 12. The pressing deformation measuring device 12 includes pressing means 16 for pressing the living body soft tissue in multiple frequency patterns so that the pressing force may periodically be changed with time sinusoidally, and data acquisition means 17 for acquiring time series data of the deformation amount appearing as a sine-wave every frequency pattern in response to the pressing force. In the intra-tissue fat measuring device 13, the intra-tissue body fat amount is found based on the frequency responses by the time series data of the deformation amounts for respective frequency patterns.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tissue fat detection system, a tissue fat measurement device, and a program. More specifically, the present invention relates to tissue fat detection useful for inferring a spatial structure arrangement of fat tissue inherent in a fiber tissue. The present invention relates to a system, a tissue fat measurement device, and a program.

  It is very important in various fields such as medical care, welfare, food, etc., to grasp rheological properties, which are information on hardness (softness), for biomaterials composed of soft tissues. However, such living soft tissues are known to have complex rheological properties, and accurate rheology can be obtained only by the data of the magnitude of the reaction force when pressed with a certain force and the amount of deformation at that time. It is difficult to accurately and quantitatively express rheological properties because physical property values representing the properties cannot be identified. That is, the soft biological tissue has a characteristic that the viscoelasticity changes with the passage of time, and the amount of deformation changes with time even when pressed with a constant force. In addition, the soft biological tissue has a characteristic that the hardness changes when the pushing force or the pushing amount exceeds a certain size. Therefore, in a living soft tissue, for example, simply measuring a single deformation amount in a single indented state and obtaining a single Young's modulus or the like is not sufficient as a physical property value representing rheological characteristics.

  By the way, recently, as an index in health management and sports science, the spatial structure of intramuscular fat existing in muscle, which is a heterogeneous tissue in which fiber tissue and adipose tissue are mixed, is attracting attention. There is a need for methods and devices that can quantitatively understand internal fat.

  Patent Document 1 discloses an X-ray CT system that obtains a value serving as an index of intramuscular fat based on a tomographic image of muscle tissue obtained by an X-ray CT apparatus.

JP 2004-81394 A

  In the X-ray CT system disclosed in Patent Document 1, since the X-ray CT apparatus is used, not only the apparatus is enlarged, but also microscopic fat fragments existing in the muscles appear in the tomographic image. Therefore, there is a problem that high resolution is required, and the subject must be irradiated with a high dose of X-rays.

  Accordingly, as a result of earnestly conducting experimental research, the present inventors have found the following events. That is, in a non-homogeneous tissue such as a muscular tissue in which adipose tissue is mixed in a fibrous tissue, when the pressing force for pressing the non-homogeneous tissue is periodically changed over time in a sine wave shape, a certain pressing force and frequency are within a predetermined range. The deformed state of the non-homogeneous tissue periodically changes with time in a sinusoidal shape at substantially the same frequency as the pressing force. Further, when the pressing force is changed over time within a predetermined range as described above, the deformation state of the non-homogeneous tissue causes a time delay with respect to the pressing force, and this time delay is caused by the fat component in the non-homogeneous tissue. If the amount is the same, it will be the same even if the frequency is changed, and will change regularly according to the amount of the fat component.

  The present invention has been devised on the basis of such inventors' knowledge, and its purpose is to make it unnecessary to acquire a tomographic image of muscle tissue or the like in an image diagnostic apparatus such as an X-ray CT apparatus, An object of the present invention is to provide a tissue fat detection system, a tissue fat measurement device, and a program capable of quantitatively grasping tissue fat with a compact device configuration.

  The present invention mainly presses a living soft tissue mixed with fat components with a predetermined force, and measures the magnitude of the pressing force at that time and the amount of deformation of the pushed soft tissue portion, And a tissue fat measurement device that obtains the amount of fat in the tissue corresponding to the amount of the fat component based on the measurement result of the pressure deformation measurement device. A pushing means for pushing the living soft tissue in a plurality of frequency patterns so as to change with time; and a data obtaining means for obtaining, for each frequency pattern, time series data of the deformation amount expressed as a sine wave corresponding to the pushing force. And the tissue fat measurement device obtains the tissue fat mass based on a frequency response based on time-series data of the deformation amount for each frequency pattern. It has taken.

  According to the present invention, in a heterogeneous tissue in which fibrous tissue and adipose tissue are mixed, a pressing force that periodically changes with time is applied to the target soft tissue, and the amount of deformation of the soft tissue over time is measured. Therefore, it is possible to detect the characteristic amount (physical property value) determined according to the amount of fat contained in the living soft tissue, and quantitatively grasp the spatial structure of fat existing in the non-homogeneous tissue based on the characteristic amount. Is possible.

The schematic block diagram of the tissue fat detection system which concerns on this embodiment. The graph showing an example of the frequency response in the time delay of a gain and a phase.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration diagram of the tissue fat detection system according to the present embodiment. In the tissue fat detection system 10, it is possible to detect the amount of fat in the tissue corresponding to the amount of fat components of the non-homogeneous living soft tissue in which the fiber tissue and the fat tissue exist. In the present embodiment, the following description will be given on the assumption that the intramuscular fat amount, which is a physical property value corresponding to the amount of fat mixed in the muscle, is detected as the tissue fat amount. Here, the detected intramuscular fat mass is used as a parameter representing the spatial structure of muscle and fat, for example, health management by grasping the spatial structure of fat components inside the muscle and athlete ability evaluation by sports science. It can be used to obtain data for evaluation and evaluation data regarding the taste of meat based on the amount of fat microscopically contained in the lean meat.

  This tissue fat detection system 10 pushes in the detection target part S of the living soft tissue including the muscle part which is the detection target of the amount of intramuscular fat with a predetermined force, the magnitude of the pressing force at that time, and the detection target part pressed in. It was calculated | required in the tissue fat measuring device 13 which calculates | requires the amount of intramuscular fat based on the measurement result of the pressure deformation measuring device 12 which measures the deformation amount of S, the pressure deformation measuring device 12, and the tissue fat measuring device 13. And an information presentation device 14 for presenting information based on the amount of intramuscular fat and the amount of intramuscular fat.

  The pressing deformation measuring device 12 includes the pressing means 16 provided so as to be able to push the detection target part S with a predetermined force, and time series data of the pressing force to the detection target part S, and the deformation amount of the detection target part S. Data acquisition means 17 for acquiring time series data is provided.

  The pushing means 16 includes an indenter 19 that is pushed in contact with the detection target portion S, an actuator 20 that includes a motor that serves as power for moving the indenter 19 away from the detection target portion S, and an actuator. And a force control unit 22 that measures the pushing force of the indenter 16 on the detection target part S at regular intervals based on detection of the reaction force from the detection target part S. Has been.

  The drive control unit 21 feeds back the measurement result of the force sensor 22 so that the pushing force to the detection target site S due to the operation of the indenter 19 periodically changes with a preset amplitude and frequency. Is controlled. Specifically, the drive control unit 21 controls the drive of the actuator 20 so that the relationship of the pressing force with respect to time periodically changes in a sine wave shape having an amplitude and a frequency set in advance by the user. In the subsequent processing for determining the amount of intramuscular fat, the indenter 19 is operated with a plurality of frequency patterns that are at least two patterns, and the amount of deformation of the detection target portion S acquired by the data acquisition unit 17 for each frequency pattern. Series data is used.

The data acquisition means 17 detects the driving amount of the actuator 20 corresponding to the movement amount of the indenter 19 together with time series data of the pushing force to the detection target site S using a sensor (not shown) at predetermined time intervals. The deformation amount (displacement amount) of the detection target portion S pressed by the indenter 19 is obtained every predetermined time, and time series data of the deformation amount is obtained. That is, here, as the time series data of the pushing force, an input sine wave (f = f ₀ sin (ωt)) that is a relational expression between the time t and the pushing force f is specified and the time series of the deformation amount is specified. As data, an output sine wave (x = x ₀ sin (ωt + φ)), which is a relational expression between time t and deformation amount x, is obtained. In each of these equations, ω is the frequency, f ₀ is the amplitude of the pushing force, x ₀ is the amplitude of the deformation amount, and φ is the time delay of the phase of the output sine wave with respect to the input sine wave. Represent. According to the experimental study by the present inventors, in a predetermined region where the amplitude f _{0 of the} indentation force and the amplitude x _{0 of the} deformation amount are small, the indentation force is expressed as a sine wave as time passes. When it is changed, the amount of deformation is also found to be a sine wave having the same frequency ω and changes with time. In the present invention, the data in the predetermined area where this property can be used will be described later. In addition, the amount of intramuscular fat is calculated. Accordingly, the pressure f is applied to the detection target portion S after the amplitude f ₀ and the frequency ω are adjusted in advance so that an output sine wave having such properties can be obtained.

  The tissue fat measurement device 13 is configured by a computer including an arithmetic processing device such as a CPU and a storage device such as a memory and a hard disk, and a program for causing the computer to function as the following units is installed.

The tissue fat measuring apparatus 13 includes a gain calculating unit 24 for determining a gain A that represents the percentage of the amplitude x ₀ of the amount of deformation of the push force for the amplitude f _0, a frequency response deriving means for obtaining a relational expression of gain A and the frequency ω 25 and tissue fat calculation means 26 for obtaining the amount of intramuscular fat based on the relational expression obtained by the frequency response deriving means 25.

In the gain calculation unit 24, when operating the indenter 19 at a plurality of frequency patterns for each frequency Bataan, the amplitude x ₀ of the amount of deformation of the output sine wave of that time, the input sine wave at that time The gain A (A = x ₀ / f ₀ ) is obtained for each frequency ω by dividing by the amplitude f ₀ of the pushing force.

上式（１）において、ｒは、周波数ωの変化に対するゲインＡの変化割合である傾きを表し、この傾きは、本発明者らの研究結果によれば、生体軟組織の弾性要素と粘性要素の比率を数値化した指標値である粘弾性比率ｒに対応し、０から１までの値を採る。ここで、粘弾性比率ｒが、０の場合に完全弾性体となる一方、１の場合に完全粘性体（流動体）となる。なお、式（１）の切片を表すＧは、本発明者らの研究結果によれば、生体軟組織の硬さに対応する指標値となる。 In the frequency response deriving unit 25, a relational expression between the gain A and the frequency ω is obtained as follows. That is, according to the research results of the present inventors, when the relationship between the frequency ω and the gain A is made into a log-log graph within the predetermined region where the amplitude f _{0 of the} pushing force and the amplitude x _{0 of the} deformation amount are small. Since a substantially linear relationship is established as in the lower line segment in FIG. 2, the following expression (1) is derived from each frequency ω and the gain A at that time.

In the above equation (1), r represents a gradient that is a change ratio of the gain A with respect to a change in the frequency ω. According to the research result of the present inventors, the gradient of the elastic element and the viscous element of the living soft tissue. Corresponding to the viscoelasticity ratio r which is an index value obtained by quantifying the ratio, values from 0 to 1 are taken. Here, when the viscoelasticity ratio r is 0, it becomes a complete elastic body, while when it is 1, it becomes a complete viscous body (fluid). Note that G representing the intercept of the formula (1) is an index value corresponding to the hardness of the living soft tissue according to the research results of the present inventors.

なお、本発明者らの研究結果によれば、繊維組織に脂肪組織が混在する非均質組織を対象とした場合、前述した通り、変位量に係る出力正弦波は、押込力に係る入力正弦波に対して、周波数が同一となり、脂肪組織の状態（量）に対応して位相のみがずれる結果になり、しかも、図２中上側の線分のように、周波数ωを変化させても、位相の時間遅れφがほぼ一定となることが分かっているため、周波数ωに依らない上式（２）により、筋肉内脂肪量Ｒを求めることが可能となる。なお、上式（２）によれば、脂肪組織が無い単一材料の繊維組織（肝臓等）の場合は、筋肉内脂肪量Ｒがゼロであり、粘弾性比率ｒのみによって位相の時間遅れφが決まることになる。換言すれば、筋肉内脂肪量Ｒの変化によって、位相の時間遅れφが変化することになる。 In the tissue fat calculating means 26, the following equation (2) derived from the study of the present inventors is obtained from the viscoelasticity ratio r specified by the above equation (1) and the phase time delay φ described above. Based on this, the intramuscular fat mass R is determined.

In addition, according to the research results of the present inventors, when targeting a heterogeneous tissue in which a fatty tissue is mixed in a fiber tissue, as described above, the output sine wave related to the displacement amount is the input sine wave related to the pushing force. On the other hand, the frequency becomes the same, and only the phase shifts in accordance with the state (amount) of the adipose tissue, and even if the frequency ω is changed as shown in the upper line segment in FIG. Therefore, the intramuscular fat amount R can be obtained by the above equation (2) that does not depend on the frequency ω. According to the above equation (2), in the case of a single material fiber tissue (liver or the like) having no fat tissue, the intramuscular fat amount R is zero, and the phase time delay φ only by the viscoelastic ratio r Will be decided. In other words, the phase time delay φ changes with changes in the intramuscular fat mass R.

  In the information presentation device 14, for example, the viscoelasticity ratio r obtained by the tissue fat measurement device 13, the index value G indicating the hardness of the tissue, and the intramuscular fat mass R are used as they are as numerical values, or are graphed. A configuration in which the image is directly presented to the user through a monitor (not shown) can be given.

  The information presentation device 14 is not particularly limited, and may be various display devices that can display the information as an image, speakers or stimulus presentation devices that can present the information by voice or stimulation, and the like. Can be adopted.

  Next, an operation procedure and a processing procedure for obtaining the intramuscular fat amount R in the tissue fat detection system 10 will be described.

First, the indenter 19 is set in a state where the indenter 19 is slightly pushed into the detection target site S where the intramuscular fat mass R is to be measured, and the initial set position is set according to a certain frequency or maximum pushing force (amplitude f ₀ ) designated by the user. Apply external force or loosen periodically. In other words, the indenter 19 operates so that the state of change of the pushing force with time changes periodically in a sine wave shape in a direction away from the direction in which the detection target portion S is pushed with respect to the initial set position. Then, the data acquisition means 17 measures the deformation amount of the detection target portion S pressed by the indenter 19 every predetermined time, and acquires time-series data of the deformation amount. At this time, if the time-series data of the deformation amount is a sine wave having the same frequency as the indentation force, the subsequent processing is continued, and if not, the other process related to the indentation force is performed. This is performed until the user sets the frequency and the amplitude again and obtains time-series data in which the deformation amount of the detection target portion S is sinusoidal. In such a state where time series data of sinusoidal deformation amount is obtained, the frequency of the pushing force is changed, and the time series data of the deformation amount is acquired for each frequency.

  Next, as described above, after the gain calculation unit 24 obtains the gain A for each frequency from the time series data of the deformation amount obtained for each frequency pattern performed a plurality of times, the frequency response deriving unit 25 , The relational expression between the gain A and the frequency ω is obtained, and the viscoelastic ratio r is specified. Finally, in the tissue fat calculation means 26, the muscle is calculated from the viscoelastic ratio r and the time delay φ of the phase of the output sine wave that is the time series data of the deformation amount with respect to the input sine wave that is the time series data of the indentation force. The amount of internal fat R is determined.

  The intramuscular fat amount R obtained as described above represents the amount of fat tissue entering the fiber tissue in the non-homogeneous living soft tissue where the fiber tissue and the fat tissue exist, and quantifies the spatial structure of the fat amount. It can be used as a parameter to express automatically.

  The pressure deformation measuring device 12 is not limited to the above-described structure, and can be applied to or used in combination with sensors and measuring instruments having various structures as long as the same action as described above is achieved. .

  In addition, the configuration of each part of the apparatus in the present invention is not limited to the illustrated configuration example, and various modifications are possible as long as substantially the same operation is achieved.

DESCRIPTION OF SYMBOLS 10 Tissue fat detection system 12 Press deformation measuring device 13 Tissue fat measuring device 16 Pushing means 17 Data acquisition means 24 Gain calculating means 25 Frequency response deriving means 26 Tissue fat calculating means

Claims (5)

A pressing deformation measuring device for pressing a living soft tissue mixed with a fat component with a predetermined force, and measuring the amount of pressing force at that time and the amount of deformation of the pressed soft living tissue; and the pressing deformation measuring device. With a tissue fat measurement device that calculates the amount of fat in the tissue corresponding to the amount of the fat component based on the measurement result,
The pressing deformation measuring device includes a pressing unit that presses the living soft tissue in a plurality of frequency patterns so that the pressing force periodically changes in a sine wave shape, and the deformation that appears as a sine wave corresponding to the pressing force. Data acquisition means for acquiring time-series data of an amount for each frequency pattern,
In the tissue fat measurement device, the tissue fat amount is obtained based on a frequency response based on time-series data of the deformation amount for each frequency pattern.   The tissue fat measurement device includes a gain calculation unit that obtains a gain that represents a ratio of an amplitude of the deformation amount to an amplitude of the indentation force, and the relationship between the indentation force and the gain with respect to the frequency of the deformation amount that are mutually the same. The tissue response according to claim 1, further comprising: frequency response deriving means for obtaining an expression; and tissue fat calculating means for obtaining the tissue fat mass based on a relational expression obtained by the frequency response deriving means. Fat detection system. In the frequency response deriving means, a viscoelastic ratio representing a change ratio of the gain with respect to a change in the frequency is specified from the relational expression,
3. The intra-tissue fat calculating means obtains the intra-tissue fat amount from a mathematical formula stored in advance based on the viscoelastic ratio and a time delay of the phase of the deformation amount with respect to the indentation force. The tissue fat detection system as described. When the living soft tissue mixed with a fat component is pushed in with a pushing force that periodically changes with time in a sinusoidal manner for each of a plurality of frequency patterns, the amount of deformation of the living soft tissue in the sinusoidal shape obtained with each frequency pattern In the tissue fat measurement device for obtaining the amount of fat in the tissue corresponding to the amount of the fat component based on the series data,
Gain calculating means for obtaining a gain representing a ratio of the amplitude of the deformation amount to the amplitude of the pushing force; and a frequency response deriving means for obtaining a relational expression of the gain with respect to the frequency of the pushing force and the deformation amount which are mutually the same. A tissue fat measurement device comprising: tissue fat calculation means for obtaining the tissue fat mass based on the relational expression obtained by the frequency response deriving means. When the living soft tissue mixed with a fat component is pushed in with a pushing force that periodically changes with time in a sinusoidal manner for each of a plurality of frequency patterns, the amount of deformation of the living soft tissue in the sinusoidal shape obtained with each frequency pattern Based on the series data, in a computer program for causing the tissue fat measuring device to calculate the amount of fat in the tissue corresponding to the amount of the fat component,
Gain calculating means for obtaining a gain representing a ratio of the amplitude of the deformation amount to the amplitude of the pushing force; and a frequency response deriving means for obtaining a relational expression of the gain with respect to the frequency of the pushing force and the deformation amount which are mutually the same. A program for a tissue fat measurement device, which causes the computer to function as tissue fat calculation means for obtaining the tissue fat mass based on the relational expression obtained by the frequency response deriving means.

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