JP6633854B2 - Ultrasonic measuring device - Google Patents

Description

  The present invention relates to an ultrasonic measurement device, and more particularly to an apparatus for obtaining an index value of fat mass using ultrasonic waves.

  2. Description of the Related Art There is known an apparatus for measuring properties of a tissue or the like in a subject based on a signal obtained by transmitting / receiving an ultrasonic wave to / from a subject such as a living body. For example, Patent Literature 1 discloses an apparatus that transmits and receives ultrasonic waves to and from a living body to measure the thickness of fat tissue in the living body from the transmission speed of the ultrasonic wave that has passed through the living body. . Patent Literature 1 discloses or suggests a specific example in which an abdomen in a living body is set as a measurement target site.

JP 2001-128972 A

  By the way, since the tissue properties in the measurement target site (for example, abdomen and thighs) are not always uniform, for example, if the transmission speed (sound speed) measurement path in the target site is different, the measured transmission speed A difference also occurs in (sound speed), and a measurement result (for example, the thickness of adipose tissue) obtained based on the transmission speed also varies.

  Therefore, when measuring the fat amount or the like of the target site based on the sound speed in the target site, a decrease in measurement accuracy (variation in measurement results, etc.) due to a difference in a path (measurement part) for measuring the sound speed is suppressed. Desirable.

  The present invention has been made in view of the background art described above, and an object of the present invention is to improve the accuracy of an index value of fat mass obtained by using ultrasonic waves.

  A suitable ultrasonic measurement device that meets the above-described object is an ultrasonic transmitting and receiving unit that transmits and receives ultrasonic waves for each of a plurality of search paths in a region including a target part, and each of the plurality of search paths. A path specifying unit that specifies a reference path to be a reference for measurement in the target part based on the received signal of the propagated ultrasonic wave; and It is characterized by having a sound speed measuring unit that obtains sound speed measurement data, and an index value deriving unit that derives an index value of fat mass in the target site based on the sound speed measurement data.

  As a target part to be measured by the above-mentioned device, a thigh of a subject or the like is suitable. For example, it is possible to estimate or diagnose the exercise ability (for example, walking ability) of the subject from the fat amount in the muscle group in the thigh of the subject. Of course, a part other than the thigh (abdominal part, arm, etc.) may be the target part.

  Further, it is desirable that the route suitable as the reference route or the condition as the suitable route in the above configuration is determined, for example, according to the target part. For example, if there is a medically standardized or recommended route for a target site, that route is set as a reference route for the target site. Of course, the reference route or the position through which the reference route passes may be designated according to the shape of the target site, the tissue properties in the target site, and the like.

  In addition, the index value of the fat amount in the above configuration is a value serving as a guide for evaluating the fat amount. Specifically, a numerical value (eg, fat thickness, fat area, fat volume) representing the amount of fat itself may be derived as an index value, or may be obtained by comparing other tissues with fat. A value (for example, body fat percentage) or the like may be derived as an index value. In addition, the measurement data of the sound velocity may be directly used as the index value of the fat amount.

  According to the above-described device, a reference path serving as a reference for measurement in the target portion is designated, and measurement data of sound speed is obtained on the reference path. Further, an index value of fat mass is derived based on the measurement data. For this reason, for example, variations in measurement data and index values due to differences in routes are reduced, and desirably, the variations are eliminated, and, consequently, the accuracy of the index values of fat mass is increased.

  In a preferred specific example, the route specifying unit is configured to specify a position of a skin surface of the target site and a position of a bone of the target site based on a reception signal obtained from each of the plurality of search routes, thereby obtaining the skin. A path determined according to the position of the surface and the position of the bone is set as the reference path.

  In a preferred specific example, the route specifying unit includes a first search route corresponding to a position of a skin surface of the target site and a second search route corresponding to a position of a bone in the target site from among the plurality of search routes. And specifying the reference route between the first search route and the second search route.

  In a preferred specific example, the path specifying unit is configured to determine the first search path and the first search path from among the plurality of search paths based on a magnitude of an ultrasonic pulse waveform included in a reception signal obtained from each of the search paths. Selecting a second search route.

  In a preferred embodiment, the ultrasonic transmission / reception unit includes two ultrasonic transducers, and receives the ultrasonic wave transmitted from one of the two ultrasonic transducers on the other, thereby forming the plurality of search paths. Transmitting and receiving ultrasonic waves for each of the search paths.

  In a preferred embodiment, the ultrasonic transmission / reception unit transmits / receives ultrasonic waves in a plurality of measurement paths within a reference plane including the reference path, and the sound velocity measurement unit receives the ultrasonic waves transmitted through the plurality of measurement paths. Measurement data of sound velocity at a point of interest in the reference plane is obtained based on the signal.

  ADVANTAGE OF THE INVENTION According to this invention, the precision of the index value of the fat amount obtained using an ultrasonic wave is improved. For example, according to a preferred aspect of the present invention, a reference path serving as a reference for measurement in a target site is specified, measurement data of sound velocity is obtained in the reference path, and further, a fat amount is determined based on the measurement data. Since the index value is derived, for example, variations in measurement data and index values due to differences in routes are reduced, and the variations are desirably eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall configuration diagram of an ultrasonic measurement device suitable for implementing the present invention. FIG. 2 is a diagram for describing a specific example of a measurement state of the ultrasonic measurement device in FIG. 1. FIG. 4 is a diagram illustrating a specific example of a received signal of an ultrasonic wave propagated through each path. It is a figure for explaining the example of sound velocity measurement. It is a figure which shows the other example of a measurement of a thigh. FIG. 9 is a diagram illustrating a specific example of measurement based on a plurality of measurement paths. It is a flowchart which shows the procedure of the measurement based on several measurement paths.

  FIG. 1 is a diagram showing the overall configuration of an ultrasonic measuring apparatus suitable for implementing the present invention. The ultrasonic measuring device shown in FIG. 1 includes a vibrator unit, a main body of the device, a vibrator moving mechanism 16 and a water temperature control unit 18, obtains sound velocity measurement data of a measurement target portion, and performs the measurement based on the sound velocity measurement data. It has a function of deriving an index value of fat mass in the target site.

  The vibrator unit includes two array vibrators 12 and 13 and a water bag 14. Each of the two array transducers 12 and 13 includes a plurality of transducers (ultrasonic transducers). Each of the array vibrators 12 and 13 is a one-dimensional array vibrator in which a plurality of vibrating elements are one-dimensionally arranged or a two-dimensional array vibrator in which a plurality of vibrating elements are two-dimensionally arranged.

  The inside of the water bag 14 is filled with water, which is a medium for ultrasonic waves. Note that another ultrasonic medium may be used instead of water. The water bag 14 is provided between the two array transducers 12 and 13. The water bag 14 is provided in close contact with each transducer surface of the two array transducers 12 and 13, and the water in the water bag 14 is transmitted and received using the two array transducers 12 and 13. Functions as a medium for transmitting sound waves.

  Next, the configuration inside the apparatus main body will be described. The transmission / reception unit 20 controls transmission and reception of ultrasonic waves by the two array transducers 12 and 13. The transmission / reception unit 20 outputs a transmission signal of a transmission pulse obtained from the pulse generation unit 22 to the two array transducers 12 and 13 to transmit a pulsed ultrasonic wave corresponding to the transmission pulse. In addition, the signal obtained from the two array transducers 12 and 13 that have received the ultrasonic waves is subjected to reception processing such as amplification processing (reception amplifier processing), and the reception signal after the reception processing is transmitted to the pulse detection unit 24. Output.

  As will be described in detail later, when measuring the speed of sound in the target portion, one of the two array transducers 12 and 13 is a transmission transducer and the other is a reception transducer. Therefore, when measuring the sound speed, the transmission / reception unit 20 outputs the transmission signal of the transmission pulse to the transmission vibrator, and performs reception processing of the signal obtained from the reception vibrator.

  The pulse generator 22 outputs a transmission pulse of an ultrasonic wave at the timing of generation of the trigger signal output from the trigger generator 30. The trigger signal generated by the trigger generation unit 30 is also output to the sound velocity measurement unit 50. The pulse detection unit 24 detects an ultrasonic reception pulse included in a reception signal obtained from the transmission / reception unit 20. The pulse detection unit 24 detects, for example, a signal portion in the received signal where the peak value exceeds a reference value (threshold) that can be regarded as a pulse as a received pulse.

  The route specifying unit 40 specifies a route (reference route) serving as a reference for measuring the speed of sound in the target part. The sound velocity measurement unit 50 obtains measurement data of the sound velocity in the target site based on the reception signal of the ultrasonic wave that has propagated along the route specified as the measurement reference. Then, the fat mass calculation unit 60 derives an index value related to fat mass in the target site based on the measurement data of the sound speed. The derived index value is displayed on the display unit 70. The processes in the route specifying unit 40, the sound speed measuring unit 50, and the fat amount calculating unit 60 will be described later in further detail.

  The control unit 100 controls the entire inside of the ultrasonic measurement device of FIG. Instructions received from a user such as a doctor or a laboratory technician via the operation device 90 are also reflected in the overall control by the control unit 100. The vibrator moving mechanism 16 is a mechanism for mechanically moving the vibrator unit, and the water temperature control unit 18 controls the water temperature in the water bag 14.

  1, the transmission / reception unit 20, the pulse generation unit 22, the pulse detection unit 24, the trigger generation unit 30, the route designation unit 40, the sound velocity measurement unit 50, and the fat mass calculation unit 60 are included in the configuration shown in FIG. Each unit of the water temperature control unit 18 can be realized by using hardware such as an electric and electronic circuit and a processor, and a device such as a memory may be used as necessary in the realization. Further, at least a part of the functions corresponding to the respective units may be realized by a computer. That is, at least a part of the function corresponding to each unit described above may be realized by cooperation between hardware such as a CPU, a processor, and a memory, and software (program) that defines the operation of the CPU and the processor.

  A preferred specific example of the display unit 70 is a liquid crystal display or the like, and the operation device 90 can be realized by, for example, at least one of a mouse, a keyboard, a trackball, a touch panel, other switches, and the like. The control unit 100 can be realized by, for example, cooperation between hardware such as a CPU, a processor, and a memory, and software (program) that defines operations of the CPU and the processor.

  The overall configuration of the ultrasonic measurement device in FIG. 1 is as described above. Next, a specific example of a function realized by the ultrasonic measurement device of FIG. 1 will be described in detail. In addition, about the structure shown in FIG. 1 (each part with a reference numeral), the reference numeral in FIG. 1 is used in the following description.

  FIG. 2 is a diagram for explaining a specific example of a measurement state of the ultrasonic measurement device of FIG. FIG. 2 illustrates a cross section (a cross section perpendicular to the longitudinal direction of the thigh T) of the thigh T, which is a preferred specific example of the target portion. In FIG. 2, a two-dimensional plane corresponding to the cross section of the thigh T is represented by an XY coordinate system.

  In the specific example of FIG. 2, the array transducers 12 and 13 are both one-dimensional array transducers. Each of the array transducers 12 and 13 includes a plurality of transducers (ultrasonic transducers) arranged in a line in the Y-axis direction.

  The two array transducers 12 and 13 have a relative positional relationship fixed in parallel with each other. Further, the vibrating elements of the two array vibrators 12 and 13 corresponding to each other are arranged at the same height (position in the Y-axis direction). For example, the vibrating element a of the array vibrator 12 and the vibrating element a of the array vibrator 13 are at the same height, and the vibrating element b of the array vibrator 12 and the vibrating element b of the array vibrator 13 are also at the same height. is there. Other vibrating elements (c, d, etc.) corresponding to each other are also arranged at the same height.

  A water bag 14 is provided between the two array transducers 12 and 13. The water bag 14 is filled with water that is a medium for ultrasonic waves. In the specific example of FIG. 2, a vibrator unit including two array vibrators 12, 13 and a water bag 14 provided therebetween is placed on the thigh T from the upper side (the positive direction side of the Y axis). , The water bag 14 is pressed against the thigh T. The water bag 14 is deformed so as to conform to the shape of the thigh T while being in close contact with the surface of the thigh T. Thereby, as in the specific example shown in FIG. 2, the upper part of the thigh T is disposed between the two array transducers 12 and 13 in a state of being embedded in the water bag 14.

  In the arrangement shown in FIG. 2, ultrasonic waves are transmitted from one of the two array transducers 12 and 13 to the other. In the specific example of FIG. 2, the array transducer 12 is a 1D (one-dimensional) array for transmission, and the array transducer 13 is a 1D (one-dimensional) array for reception. Then, between the two array transducers 12 and 13, ultrasonic waves are transmitted and received for each path over a plurality of paths.

  For example, first, an ultrasonic pulse wave is transmitted only from the vibration element a of the array transducer 12 for transmission, and a reception signal corresponding to the signal output from the vibration element a of the array transducer 13 for reception is obtained. Is done. As a result, a reception signal of the ultrasonic wave propagated through the path a in FIG. 2 is obtained. Next, ultrasonic waves are transmitted and received between the transmitting and receiving vibration elements adjacent to the vibration element a. Subsequently, an ultrasonic pulse wave is transmitted only from the vibration element b of the array transducer 12, and a reception signal corresponding to a signal output from the vibration element b of the array transducer 13 is obtained. That is, the reception signal of the ultrasonic wave that has propagated along the path b in FIG. 2 is obtained.

  In this way, ultrasonic waves are sequentially transmitted and received between the corresponding vibration elements, and reception signals of the ultrasonic waves that have propagated along a path connecting the corresponding vibration elements with a straight line are sequentially obtained.

  Then, a path b corresponding to the skin surface of the thigh T and a path d corresponding to the bone of the thigh T are selected based on the reception signal of the ultrasonic wave transmitted through each of the plurality of paths, and the measurement is performed. Is specified as a reference route for the route c.

  FIG. 3 is a diagram illustrating a specific example of a reception signal of an ultrasonic wave that has propagated through each path. FIG. 3 shows a specific example of the received signal corresponding to each of the paths a, b, c, and d in FIG.

  FIG. 3A shows a received signal on the path a. The path a is a path that passes only inside the water bag 14, that is, only underwater (see FIG. 2), and the attenuation of the ultrasonic wave is relatively small. Therefore, the peak value A and the amplitude A of the received pulse included in the received signal on the path a are relatively large.

  FIG. 3B shows a received signal on the path b. The route b is a route that passes through the skin surface of the thigh T (see FIG. 2), and there is scattering and attenuation of ultrasonic waves on the surface of the thigh T. , The peak value B and the amplitude B of the received pulse become smaller.

  Therefore, the path specifying unit 40 specifies the path b that passes through the skin surface of the thigh T based on the peak value of the received pulse included in the received signal. For example, in the specific example shown in FIG. 2, the peak value of the received pulse included in the received signal of each path is sequentially confirmed from the upper side (the positive direction side of the Y axis), and the peak value of the received pulse is a threshold for determining the skin surface. The first path (uppermost path) that is equal to or less than B (or smaller than the threshold B) is selected as the path b that passes through the skin surface.

  In addition, the threshold value B may be a fixed value, may be set based on the peak value of the received pulse in a path that passes only underwater (for example, path a), or may be appropriately adjusted by the user. Is also good. Alternatively, the path b that passes through the skin surface may be selected using an amplitude value instead of the peak value or together with the peak value.

  FIG. 3C shows a received signal on the path c. The path c is a path that passes through the inside of the thigh T (see FIG. 2), and a path that passes through the skin surface because the ultrasonic waves are attenuated by the tissue (muscle tissue, fat tissue, or the like) in the thigh T. The peak value C of the received pulse becomes smaller than in the case of b. In general, the peak value of the received pulse tends to decrease as the distance passing through the thigh T in the path increases.

  FIG. 3D shows a received signal on the path d. The route d passes through a bone (femur) inside the thigh T (see FIG. 2). Bone has a great difference in acoustic impedance as compared with other tissues (muscle tissue, adipose tissue, etc.), and ultrasonic waves reaching the bone are strongly scattered. As a result, the peak value and amplitude of the reception pulse included in the reception signal on the path d passing through the bone become extremely small.

  Therefore, the path specifying unit 40 specifies the path d that has reached the bone of the thigh T based on the peak value of the received pulse included in the received signal. For example, in the specific example shown in FIG. 2, the peak value of the received pulse included in the received signal of each path is sequentially confirmed from the upper side (the positive side of the Y axis), and it is confirmed that the peak value of the received pulse reaches the bone. The first path (uppermost path) that is equal to or less than the threshold value D (or smaller than the threshold value D) is selected as the path d that has reached the bone.

  When the route specifying unit 40 selects a route b that passes through the skin surface of the thigh T and a route d that reaches a bone (femur) inside the thigh T, the route specifying unit 40 determines an intermediate position between the route b and the route d. , A reference path for measuring the speed of sound is specified. For example, a route in which the distance from the route b is equal to the distance from the route d, that is, the route c in the specific example of FIG. 2 is selected as the reference route. When the reference route is specified, the speed of sound (the propagation speed of the ultrasonic wave) is measured on the reference route.

  FIG. 4 is a diagram for explaining a specific example of sound speed measurement. FIG. 4A shows an enlarged view of a route c designated as a reference route in the measurement (see FIG. 2) using the thigh T as a target portion and a portion around the route c.

  The transducer distance L is the distance between the two array transducers 12 and 13. As the distance L between the transducers, for example, a known design value can be used. Also, the distance L between transducers (= sound speed × propagation time) is calculated from the propagation time of the ultrasonic wave in a route that passes only through the water (for example, the route a in FIG. 2) and the speed (sound speed) of the ultrasonic wave in the water. Is also good.

  The underwater distances W1, W2 are measured by each of the two array transducers 12, 13 transmitting and receiving ultrasonic waves. For example, the time required for the vibrating element c of the array vibrator 12 to transmit ultrasonic waves and the same vibrating element c to receive ultrasonic waves reflected from the skin surface of the thigh T, The underwater distance W1 can be calculated from the speed (the sound speed). Similarly, the time from when the vibrating element c of the array vibrator 13 transmits ultrasonic waves until the same vibrating element c receives the ultrasonic waves reflected from the skin surface of the thigh T, and the ultrasonic wave in water The underwater distance W2 can be calculated from the speed (sound speed) of the vehicle.

  The thigh length X is a value obtained by subtracting the underwater distance W1 and the underwater distance W2 from the inter-vibrator distance L (X = L−W1−W2).

  The sound velocity measuring unit 50 first transmits an ultrasonic transmission pulse from the vibration element c of the array vibrator 12 on the path c, and the vibration element c of the array vibrator 13 receives the ultrasonic reception pulse. The time TL until the measurement is performed is measured. The timing at which the transmission pulse is transmitted from the vibration element c of the array vibrator 12 is the same as the generation timing of the trigger signal obtained from the trigger generation unit 30 or can be known from the generation timing of the trigger signal. The timing at which the vibration element c of the array vibrator 13 receives the reception pulse is determined by the pulse detection unit 24 in a signal portion where the peak value exceeds a reference value (threshold) that can be regarded as a pulse in the reception signal of the vibration element c. This is the detected timing.

  Next, the sound velocity measuring unit 50 subtracts the propagation time T1 of the underwater distance W1 and the propagation time T2 of the underwater distance W2 from the time TL, which is the propagation time of the ultrasonic wave between the two vibrating elements c, to obtain the thigh region. The transit time Tx of T (Tx = TL−T1−T2) is calculated. The propagation time T1 is the time (reciprocating time) from when the vibration element c of the array transducer 12 transmits ultrasonic waves to when the same vibration element c receives ultrasonic waves reflected from the skin surface of the thigh T (the round trip time). Is half of The propagation time T2 is the time (reciprocating) between the time when the vibration element c of the array transducer 13 transmits ultrasonic waves and the same vibration element c receives the ultrasonic waves reflected from the skin surface of the thigh T. Time).

  Then, the sound speed measurement unit 50 calculates the propagation speed Vx of the ultrasonic wave in the thigh T (Vx = X / Tx), that is, the sound speed Vx in the thigh T, from the thigh length X and the passage time Tx.

  As shown in FIG. 4A, on the path c passing through the thigh T, tissues other than muscles, such as skin tissue from the skin surface to the muscle and fascia tissue between the muscles, etc., are present. Although included, the region occupied by the muscle (the length on the route c) is dominant, so the calculated sound speed Vx in the thigh T is regarded as the sound speed of the muscle tissue in the thigh T. be able to.

  According to experiments using the animal tissue of the present inventors, for example, within the range of about 25 to 40 degrees Celsius, the sound velocity in fat is lower than the sound velocity in muscle. Was done. Therefore, at a human (human) body temperature (about 37 degrees Celsius), the higher (larger) sound velocity (sound velocity of muscle tissue) Vx in the thigh T, the greater the amount of muscle in the thigh T, and It can be estimated that the lower (smaller) sound velocity Vx in the part T, the greater the amount of fat in the thigh T.

  Therefore, the fat amount calculation unit 60 calculates an index value of the fat amount in the thigh T based on the sound speed Vx in the thigh T measured (calculated) in the sound speed measurement unit 50. For example, if the correspondence between the numerical value of the sound speed Vx and the numerical value of the fat mass is clarified in advance by experimental results or the like, the numerical value of the fat mass can be obtained from the numerical value of the sound speed Vx based on the corresponding relationship. As the index value of the fat amount, the sound speed Vx may be used as it is, or an index (“large”, “medium”, “small”, etc.) indicating the amount of fat mass (smallness) is derived. You may. Of course, a value (for example, body fat percentage) obtained by comparison with other tissues may be calculated as the index value of the fat amount.

  Further, as shown in FIG. 4 (2), a plurality of paths c (c1 to cn) (n is a natural number of 2 or more) passing through the thigh T may be set. For example, a plurality of routes c1 to cn are set near the route c (FIG. 4A) designated as the reference route. In the specific example of FIG. 4B, five routes c1 to c5 are set around the route c designated as the reference route.

The sound velocity measuring unit 50 calculates a sound velocity Vx (Vx = X / Tx) in the thigh T for each path cn, and for example, statistical representative values of a plurality of sound velocities Vx obtained from a plurality of paths c1 to cn. (Average value, maximum value, minimum value, etc.). Then, the fat mass calculating unit 60 calculates an index value of the fat mass in the thigh T based on the representative value of the sound speed Vx in the thigh T measured (calculated) in the sound speed measuring unit 50.

  By using the representative values of the plurality of sound velocities Vx obtained from the plurality of paths c1 to cn, for example, it is possible to reduce the variation in measurement due to the difference in the shape of the thigh T.

  The index value of the fat mass obtained by the fat mass calculation unit 60 is displayed on the display unit 70 in a display form such as a numerical value, a character, a symbol, and a graph.

  In obtaining the index value of the fat amount in the human thigh T, it is desirable that the water temperature in the water bag 14 be controlled by the water temperature control unit 18 to a temperature close to, for example, the human body temperature. Specifically, the water temperature in the water bag 14 is controlled within a range from about 36 degrees Celsius to about 38 degrees Celsius, and desirably 37 degrees Celsius is set as the target temperature for control.

  FIG. 5 is a diagram illustrating another measurement example of the thigh T. FIG. 5 shows a specific example in which two array transducers 12 and 13 are arranged along the longitudinal direction of the thigh T to measure the speed of sound.

  In the specific example of FIG. 5, both the array transducers 12 and 13 are one-dimensional array transducers. Each of the array transducers 12 and 13 is constituted by a plurality of transducers (ultrasonic transducers) arranged in a row in the longitudinal direction (Z-axis direction) of the thigh T.

  The two array transducers 12 and 13 have a relative positional relationship fixed in parallel with each other. Further, the vibrating elements corresponding to each other of the two array vibrators 12 and 13 are arranged at the same position in the longitudinal direction (position in the Z-axis direction).

  In the specific example of FIG. 5, two array vibrators 12, 13 are arranged with the thigh portion T interposed therebetween, and the vibrators are arranged in a state where the relative positional relationship between the two array vibrators 12, 13 is fixed. It is driven by the moving mechanism 16 to move in the vertical direction (Y-axis direction).

  In the specific example of FIG. 5, while moving the two array transducers 12, 13, ultrasonic waves are transmitted and received between the two array transducers 12, 13 over a plurality of paths for each path. For example, while changing the heights (coordinates in the Y-axis direction) of the two array vibrators 12 and 13 stepwise in order from the upper side (the positive direction side of the Y-axis), a typical vibrating element is provided at each height. Ultrasonic waves are transmitted and received between each other. For example, at each height, an ultrasonic wave is transmitted from the vibrating element m at the center of the transmitting array vibrator 12, and the vibrating element m at the center of the receiving array vibrator 13 receives the ultrasonic wave. .

  Thus, at each height, a linear path connecting the transmitting vibration element m and the receiving vibration element m is formed, and a plurality of paths corresponding to a plurality of heights are formed in order from the upper side. Further, similarly to the specific example of FIG. 2, the received signals of the respective paths are sequentially acquired from the upper side (the positive direction side of the Y axis).

  Further, by the processing described with reference to FIG. 3, the path specifying unit 40 determines the path (height) passing through the skin surface of the thigh T based on the peak value of the received pulse included in the received signal. A path (height) passing through a bone (femur) of the thigh T is specified, and a reference path (measurement height) for measuring the speed of sound is specified between a path passing through the skin surface and a path passing through the bone. . When the measurement height is designated, the sound speed (the propagation speed of the ultrasonic wave) is measured at that height (the coordinate in the Y-axis direction in FIG. 5). In the measurement example shown in FIG. 5, in the reference plane at the measurement height, that is, in the reference plane including the reference path, ultrasonic waves are transmitted / received through a plurality of measurement paths, and reception of ultrasonic waves transmitted through the plurality of measurement paths is performed. Based on the signal, measurement data of the sound velocity at the point of interest in the reference plane is derived.

  In the measurement example shown in FIG. 5, a water bag 14 (see FIG. 1) provided between the two array transducers 12 and 13 may be used. For example, the two array transducers 12 and 13 may be used. And the thigh T may be put in a water tank, and the water in the water tank may be used as a medium for ultrasonic waves. Of course, other media may be used instead of water.

  FIG. 6 is a diagram illustrating a specific example of measurement based on a plurality of measurement paths. The thigh T shown in FIG. 6 is a longitudinal section of the thigh T at the measurement height specified in the specific example of FIG. The two array transducers 12 and 13 shown in FIG. 6 are arranged at the measurement height specified in the specific example of FIG.

  In the specific example of FIG. 6, ultrasonic waves are sequentially transmitted from the plurality of vibrating elements constituting the transmitting array vibrator 12 toward the thigh T for each vibrating element, and each vibrating element (transmitting vibration For each element, a received signal is obtained by a plurality of vibrating elements constituting the receiving array vibrator 13. For example, as shown in FIG. 6, an ultrasonic wave is transmitted from one vibration element of the array transducer 12, and a reception signal is obtained in all the vibration elements of the array transducer 13. Then, ultrasonic waves are transmitted for each of the vibrating elements of the array vibrator 12, and received signals are obtained for all of the vibrating elements of the array vibrator 13.

  In this way, as shown in FIG. 6, received signals are obtained in a plurality of measurement paths in a longitudinal section (corresponding to a reference plane) of the thigh T, and, for example, measurement data of sound speed is derived for each path. Furthermore, the measurement data at the point of interest in the longitudinal section (reference plane) of the thigh T may be derived based on the plurality of measurement data obtained through the plurality of measurement paths.

  For example, the distribution of sound speed (measurement data) in the longitudinal section of the thigh T based on a plurality of measurement data obtained by a plurality of measurement paths using the principle of CT calculation (CT image reconstruction). It may be derived. In the CT operation, for example, as disclosed in the reference document (WO2013105583 A1), an algebraic reconstruction method (ART), a contemporaneous number reconstruction method (SART), or an ordered subset contemporaneous number reconstruction method (OS-SART) ) May be used.

  FIG. 7 is a flowchart illustrating a procedure of measurement based on a plurality of measurement paths. First, the two array transducers 12 and 13 are arranged on the thigh of the subject (S701), and the temperature control of the water bag 14 is started (S702).

  Received signals are obtained in a plurality of paths while moving the two array transducers 12 and 13 in the vertical direction. Based on the received signals in the plurality of paths, the positions of the skin surface and the bones (height) of the thigh are determined. ) Is detected (S703: see FIG. 5). Further, the measurement height (reference plane) is specified according to the skin surface of the thigh and the position of the bone, and the two array transducers 12 and 13 are moved to the measurement height (S704: FIG. 6). reference).

  Next, a transmission pulse is transmitted by vibrating element n (element number n) included in array vibrator 12 for transmission (S705), and a received signal is generated by vibrating element m (element number m) included in array vibrator 13 for receiving. Is acquired (S706). Note that both n and m are natural numbers whose initial values are 1. Then, the measurement data of the sound velocity in the path (n → m) connecting the transmitting vibration element n and the receiving vibration element m is derived (S707: see FIG. 4).

  Next, it is confirmed whether or not the element number m for reception is the last number (S708). In the specific example shown in FIG. 7, the number of receiving vibration elements is 64, and it is confirmed whether or not the element number m is 64. If the element number m for reception is not 64, 1 is added to the element number m (m = m + 1), and the process returns to S705. Thus, the processing from S705 to S707 is repeated until the receiving element number m reaches 64. As a result, the sound velocities in 64 paths obtained by combining one vibrating element n for transmission and all (64) vibrating elements m for reception are measured.

  If it is confirmed in S708 that the element number m has reached 64, it is confirmed whether or not the transmission element number n is the last number (S709). In the specific example shown in FIG. 7, the number of transmitting vibration elements is also 64, and it is confirmed whether or not the element number n is 64. If the element number n for transmission is not 64, 1 is added to the element number n (n = n + 1), and the process returns to S705. Then, the processing from S705 to S709 is repeated until the transmission element number n reaches 64.

  In this way, the processing is repeated by the branch in S708 and the branch in S709, so that all paths (64 × 64 pieces) corresponding to all combinations of 64 vibration elements n for transmission and 64 vibration elements m for reception. Measurement data of the speed of sound in the path) is obtained.

  Then, based on the sound velocity measurement data corresponding to all the paths, the sound velocity at the point of interest in the longitudinal section (see FIG. 6) of the thigh is derived using, for example, the principle of CT calculation (S710). In S710, a two-dimensional distribution of sound speed (measurement data) in the longitudinal section of the thigh may be derived.

  As described above, the preferred embodiments of the present invention have been described. However, the above-described embodiments are merely examples in every aspect, and do not limit the scope of the present invention. The present invention includes various modifications without departing from the essence thereof.

  12, 13 Array vibrator, 14 water bag, 16 vibrator moving mechanism, 18 water temperature control unit, 20 transmitting / receiving unit, 22 pulse generating unit, 24 pulse detecting unit, 30 trigger generating unit, 40 route specifying unit, 50 sound speed measuring unit , 60 fat mass calculation unit, 70 display unit, 90 operation device, 100 control unit.

Claims (3)

An ultrasonic transmitting and receiving unit that transmits and receives ultrasonic waves for each of the plurality of search paths within the area including the target part,
Based on the magnitude of the pulse waveform included in the received signal of the ultrasonic wave transmitted through each of the plurality of search paths, a first one corresponding to the position of the skin surface of the target site from among the plurality of search paths. A search path and a second search path corresponding to the position of the bone in the target site are selected, and a reference path serving as a measurement reference in the target site is defined between the first search path and the second search path. A routing section to be specified;
A sound speed measurement unit that obtains measurement data of sound speed in the target site based on a received signal of an ultrasonic wave that has propagated through the reference path,
An index value deriving unit that derives an index value of fat mass in the target site based on the measurement data of the sound velocity,
Having,
An ultrasonic measuring device characterized by the above-mentioned. The ultrasonic measuring device according to claim 1 ,
The routing unit specifies a plurality of said reference path between said second searched route and the first searched route,
The sound velocity measurement unit acquires measurement data of sound velocity in the target portion for each of the plurality of reference paths,
The index value deriving unit derives an index value of fat mass in the target site based on a statistical representative value of a plurality of measurement data obtained from a plurality of the reference paths,
An ultrasonic measuring device characterized by the above-mentioned. The ultrasonic measuring device according to claim 1 ,
The ultrasonic transmission / reception unit includes two ultrasonic vibrators, and receives ultrasonic waves transmitted from one of the two ultrasonic vibrators on the other, thereby obtaining each of the plurality of search paths. Send and receive ultrasonic waves to and from
An ultrasonic measuring device characterized by the above-mentioned.