JP2017192479A - Image forming device and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for a user to easily grasp a position of a predetermined organ in a living body.SOLUTION: An image forming device 10 includes an arithmetic processing part 350 for forming an ultrasonic image based on a reception signal obtained by receiving a reflection wave from a living body of an ultrasonic wave incident into the living body. The arithmetic processing part 350 calculates an attenuation feature value at each position along the incident direction of the ultrasonic wave based on the reception signal (371), detects a position of a predetermined organ in the living body based on the attenuation feature value, and displays the position of the predetermined organ.SELECTED DRAWING: Figure 16

Description

  The present invention relates to an image generation apparatus and an image generation method for generating an ultrasonic image.

  2. Description of the Related Art Conventionally, there is known an ultrasonic diagnostic apparatus that performs ultrasonic measurement using an ultrasonic probe (probe) and generates an ultrasonic image. For example, Patent Document 1 discloses a technique in which an ultrasonic image with good image quality can be obtained by recognizing a blood vessel traveling direction and optimizing an angle formed between the blood vessel traveling direction and the sound ray direction.

JP 2003-102731 A

  By the way, the ultrasonic diagnostic apparatus is used not only for observing and diagnosing a target site but also for confirming or specifying the position of a predetermined organ existing under the skin. For example, a position of a puncture target such as a blood vessel is confirmed while viewing an ultrasonic image, and a position where a puncture needle is inserted (puncture position) is determined. In such a case, it is important to know where the target organ exists under the skin where the ultrasonic probe is applied. Accordingly, the present invention has been devised for the purpose of providing a technique that allows a user to easily grasp the position of a predetermined organ in a living body.

  1st invention for solving the said subject is an image generation apparatus provided with the arithmetic processing part which produces | generates an ultrasonic image based on the received signal which received the reflected wave from the said biological body of the ultrasonic wave which injected into the biological body. The arithmetic processing unit calculates an attenuation feature value at each position along the incident direction of the ultrasonic wave based on the received signal, and based on the attenuation feature value, calculates a predetermined organ in the living body. It is an image generation device that executes a position detection and a display of the position of the predetermined organ.

  According to another aspect of the invention, there is provided an image generation method for generating an ultrasonic image based on a reception signal received from a reflected wave of the ultrasonic wave incident on the living body, wherein the ultrasonic wave is generated based on the reception signal. Calculating an attenuation feature value at each position along the incident direction, detecting a position of the predetermined organ in the living body based on the attenuation feature value, and displaying the position of the predetermined organ; An image generation method including the above may be configured.

  According to the first aspect of the invention, the attenuation feature value at each position (incident direction position) along the incident direction of the ultrasonic wave is calculated, and the position of the predetermined organ in the living body is calculated based on the attenuation feature value at each incident direction position. The position can be detected and displayed. According to this display, the user can easily grasp the position of the predetermined organ in the living body.

  Further, as a second invention, an ultrasonic probe in which ultrasonic elements that receive the reflected ultrasonic waves and receive the reflected waves are arranged in a plane shape, and the display includes the predetermined organ with respect to the ultrasonic elements. The image generation apparatus according to the first aspect of the invention may be configured to include displaying the relative positions of the first and second aspects.

  According to the second invention, it is possible to display the relative position of the predetermined organ with respect to the ultrasonic element that the ultrasonic probe is arranged in a plane.

  According to a third aspect of the present invention, there is provided the image generating apparatus according to the second aspect, wherein the detecting is detecting a position of the predetermined organ in a plan view as viewed from the incident direction of the ultrasonic wave. Also good.

  According to the third invention, it is possible to detect the position of the predetermined organ in a plan view viewed from the incident direction of the ultrasonic wave.

  According to a fourth aspect of the present invention, the detecting includes detecting the position of the predetermined organ in a cross section along the incident direction of the ultrasonic waves. An apparatus may be configured.

  According to the fourth invention, the position of the predetermined organ in the cross section along the incident direction of the ultrasonic wave can be detected.

  Further, as a fifth invention, the calculation processing unit further executes calculating a differential value of the attenuation feature value along the incident direction, and detecting the differential value of the attenuation feature value. The image generating apparatus according to the fourth aspect of the present invention may be configured to detect the position of the predetermined organ based on the above.

  According to the fifth aspect, the attenuation feature value is differentiated along the incident direction of the ultrasonic wave, and the position of the predetermined organ in the incident direction of the ultrasonic wave can be detected from the differential value.

  According to a sixth aspect of the present invention, calculating the attenuation feature value includes an attenuation for canceling the attenuation of the received signal using the incident signal intensity of the ultrasonic wave and the received signal intensity of the reflected wave. You may comprise the image generation apparatus of any one of the 1st-5th invention which is calculating a correction value.

  According to the sixth aspect, an attenuation correction value for canceling the attenuation of the received signal can be calculated as the attenuation feature value.

  According to a seventh aspect of the present invention, calculating the attenuation feature value includes calculating an attenuation intensity value of the received signal using the incident signal intensity of the ultrasonic wave and the received signal intensity of the reflected wave. The image generation apparatus according to any one of the first to fifth inventions may be configured.

  According to the seventh aspect, the attenuation strength value of the received signal can be calculated as the attenuation feature value.

The figure which shows the example of whole structure of an image generation apparatus. The top view of an ultrasonic probe. The schematic perspective view which shows simply the ultrasonic measurement by an ultrasonic probe. The top view which shows the subcutaneous blood vessel with which the ultrasonic probe was stuck. The schematic diagram which shows an ultrasonic image. The schematic diagram which shows another ultrasonic image. The schematic diagram which shows another ultrasonic image. The figure which shows the simple ultrasonic propagation model for demonstrating calculation of an attenuation characteristic value. The figure which graphed the attenuation | damping correction value which concerns on a y direction center scanning line. The figure which plotted the attenuation | damping correction value which concerns on another y direction center scanning line. The figure which plotted the attenuation | damping correction value which concerns on another y direction center scanning line. The figure which plotted the attenuation | damping correction value which concerns on the blood vessel center upper scanning line. The figure which graphed the attenuation correction value which concerns on the other blood-vessel center upper scanning line. The figure which graphed the attenuation correction value which concerns on the other blood-vessel center upper scanning line. The figure which shows the example of a screen structure of the display screen of an ultrasonic image. The block diagram which shows the function structural example of an image generation apparatus. The flowchart which shows the flow of the production | generation process of an ultrasonic image. The figure which shows the other example of a screen structure of the display screen of an ultrasonic image.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. It should be noted that the present invention is not limited to the embodiments described below, and modes to which the present invention can be applied are not limited to the following embodiments. In the description of the drawings, the same parts are denoted by the same reference numerals.

[overall structure]
FIG. 1 is a diagram illustrating an example of the overall configuration of the image generation apparatus 10 according to the present embodiment, and illustrates an attached state of the ultrasonic probe 16. FIG. 2 is a plan view of the ultrasonic probe 16. The image generation apparatus 10 is an apparatus that generates an ultrasonic image, and has a configuration in which the ultrasonic probe 16 is electrically connected to the processing apparatus 30 via a cable.

  The ultrasonic probe 16 has a plurality of ultrasonic elements (ultrasonic transducers) 171 that transmit and receive ultrasonic waves arranged in a matrix of a predetermined number of rows and a predetermined number of columns (see FIG. 3). An ultrasonic element (hereinafter also simply referred to as “element”) is an ultrasonic transducer that converts an ultrasonic wave and an electric signal, transmits an ultrasonic pulse of several MHz to several tens of MHz, and reflects its reflected wave. Receive. Prior to the ultrasonic measurement, the ultrasonic probe 16 is affixed and fixed by the adhesive pedestal 18 to the site (target site) of the subject 2 corresponding to the purpose of the measurement.

  The adhesive pedestal 18 has a removable adhesive layer on the skin surface, and does not easily come off or peel off even when the subject 2 moves the body. In the present embodiment, a predetermined organ in the subject 2 (living body) to be detected will be described as a blood vessel. Therefore, in the present embodiment, the adhesive pedestal 18 is such that one arrangement direction (row direction) of the elements 171 in the ultrasonic probe 16 is along the traveling direction of the blood vessel (for example, the brachial artery) 21 to be detected that travels in the target region. It is affixed as follows. The blood vessel 21 to be detected may be, for example, a radial artery, a femoral artery, a carotid artery, a subclavian artery, an aorta, or the like, and is not particularly limited.

  In this way, on the exterior of the ultrasonic probe 16 attached to the target site, as shown in FIG. 2, printing is performed along the row direction of the built-in elements 171 (direction perpendicular to the direction along the blood vessel 21). The scale is indicated by the above. Here, the element 171 is arranged in an element arrangement surface (arrangement surface) 17 indicated by a broken line in FIG.

  More specifically, the scale is described in different notation at both end edges of the upper surface of the exterior along the column direction of the elements 171. In the example shown in the drawing, five scales are written in alphabetical notation from “A” to “E” on the left edge as viewed in FIG. 2, and from “1” to the right edge. Five scales are written in numerical notation up to “5”. The rough positions of both end edges can be identified by the left and right scales. The number of scales may be set as appropriate, and may be more or less than five.

  Returning to FIG. The processing device 30 is a kind of computer control device, and acquires biological information of the subject 2 using ultrasonic measurement. Specifically, the image generation apparatus 10 makes an ultrasonic beam incident (transmitted) from the ultrasonic probe 16 to the subject 2 under the control of the processing apparatus 30, receives the reflected wave (ultrasonic echo), and receives the ultrasonic wave. Measure. Then, the reflected wave data such as the positional information of the in-vivo structure of the subject 2 and the change with time is generated by amplifying and processing the received signal of the reflected wave.

  The reflected wave data includes so-called A mode, B mode, M mode, and Doppler mode images. In the A mode, the first axis is a reception signal sampling point sequence along the scanning line direction of the ultrasonic beam (the incidence direction of ultrasonic waves), and the second axis is the reception signal intensity of the reflected wave at each sampling point. In this mode, the amplitude of the reflected wave (A mode image) is displayed. In the B mode, the reflected wave amplitude (A mode image) obtained by scanning the ultrasonic beam within a predetermined probe scanning range (scanning angle) is converted into a luminance value and visualized. In this mode, a two-dimensional ultrasonic image (B-mode image) is displayed.

  FIG. 3 is a schematic perspective view schematically showing a state where the ultrasonic probe 16 is attached to the body surface of the subject 2 and ultrasonic measurement is performed. Here, the row direction of the elements 171 along the blood vessel 21 is defined as the y direction, the column direction of the elements 171 is defined as the x direction, and the depth direction from the biological surface orthogonal to these directions is defined as the z direction.

  For example, the ultrasonic probe 16 performs ultrasonic measurement for each element 171 in each row (hereinafter also referred to as “element row”). Specifically, the elements 171 in each element row are ultrasonic waves along a scanning line in the z direction (depth direction from the living body surface) while shifting the incident position of the ultrasonic beam in the x direction by the pitch of the elements 171. Transmit and receive beams to obtain reflected wave data. Therefore, in this embodiment, a slice image on the xz plane of the target region can be obtained for each element array as the ultrasonic image I1. In each ultrasonic image I1, a short axis image of the blood vessel 21 is depicted. The obtained ultrasonic images I1 are displayed, for example, by arranging them in the order of element row numbers on a display device or the like provided in the processing device 30.

  In addition, since an A mode image is obtained in which each position on the living body surface facing each element 171 is an ultrasonic wave incident position, it is parallel to the yz plane by using the A mode image related to the incident position along the row direction. A simple ultrasonic image can also be generated. Further, not only in the column direction and the row direction, for example, if an A mode image related to an incident position along a diagonal line of the element arrangement surface 17 is used, an ultrasonic image of a plane passing through the diagonal line and orthogonal to the element arrangement surface 17 is generated. It is also possible.

[Overview]
FIG. 4 is a plan view showing the subcutaneous blood vessel 21 to which the ultrasonic probe 16 is attached, and also shows the element arrangement surface 17 of the ultrasonic probe 16. 5 to 7 are schematic diagrams showing ultrasonic images obtained by ultrasonic measurement according to the element rows R21, R23, and R25 shown in FIG. 4, and FIG. 5 shows an ultrasonic wave corresponding to the element row R21. An image I1, FIG. 6 shows an ultrasonic image I1 corresponding to the element row R23, and FIG. 7 shows an ultrasonic image I1 corresponding to the element row R25. 5 to 7, the scanning line (x-direction center scanning line) is located on the x-direction center line L <b> 21 (see FIG. 4) whose starting point (incident position of the ultrasonic beam) passes through the center of the element arrangement surface 17. ) L311, L313, and L315 are indicated by solid lines. The start point is on the center line (blood vessel center line in xy plan view) L23 (see FIG. 4) of the blood vessel 21 viewed on the xy plane, and passes through the center (blood vessel center) of the blood vessel 21 (scanning on the center of the blood vessel). Lines L321, L323, and L325 are indicated by alternate long and short dash lines.

  As described above, the ultrasonic probe 16 is affixed to the target site so that the row direction (y direction) of the element 171 is along the blood vessel 21. However, in practice, it is difficult to completely match the row direction of the element 171 with the traveling direction of the blood vessel 21. For example, in the example of FIG. 4, the blood vessel 21 passes through the vicinity of the center of the element arrangement surface 17 and runs obliquely (downward to the right) with respect to the y direction. Accordingly, when viewed in the ultrasound image, the blood vessel 21 is depicted to the left in the ultrasound image corresponding to the element array R21 (FIG. 5), and the blood vessel 21 is depicted to the right in the ultrasound image corresponding to the element array R25 ( FIG. 7). Further, in the ultrasonic image corresponding to the element row R23, the blood vessel 21 is depicted at substantially the center (FIG. 6).

  On the other hand, conventionally, for example, a position of a puncture target such as a blood vessel is confirmed while observing an ultrasonic image, and a position where a puncture needle is inserted (puncture position) is determined. However, when the image generation apparatus 10 of this embodiment is applied to such an application, what is depicted in each ultrasonic image is a short-axis image of the blood vessel 21 (for example, images as shown in FIGS. 5 to 7). Therefore, it is difficult to grasp the traveling direction of the blood vessel 21 at the target site at a glance from the display. Even in the case where an ultrasonic image parallel to the yz plane on which the long-axis image of the blood vessel 21 is depicted is displayed, the ultrasonic probe 16 and the display device are separate from each other. It is difficult to intuitively grasp whether the blood vessel 21 is traveling.

  Therefore, in this embodiment, each incident direction position along the incident direction of the blood vessel 21 (each position in the depth direction from the living body surface in this embodiment) is detected for each scanning line for each element row. And the relative position (blood vessel relative position) of the blood vessel 21 with respect to the element arrangement surface 17 is displayed and presented to a user such as a doctor.

[principle]
The ultrasonic wave incident on the subject 2 propagates while being attenuated in the subject 2. There are mainly three types of attenuation that occur: diffusion attenuation, absorption attenuation, and scattering attenuation. Diffusion attenuation is attenuation due to the sound wave spreading into a spherical shape, absorption attenuation is attenuation due to acoustic energy being absorbed and thermally converted by the medium, and scattering attenuation is attenuation due to non-uniform medium. It is. In this embodiment, attention is paid to scattering attenuation. For this purpose, first, consider a case in which the medium A for propagating ultrasonic waves contains a different medium B. However, there is no diffusion attenuation and absorption attenuation of ultrasonic waves.

Acoustic impedance Z ₁ of the medium A is calculated by the product of the average density [rho ₁ of the medium A to the average sound velocity c _1, the acoustic impedance Z ₂ of the medium B is the average density [rho ₂ of the medium B to the average sound velocity c ₂ (Equation (1)).

The reflectance S when the ultrasonic wave propagating through the medium A is reflected at the boundary surface between the media A and B is expressed by the following equation (2) using the acoustic impedances Z ₁ and Z ₂ of the media A and B. Is done.

And the transmittance | permeability T of the ultrasonic wave which permeate | transmits the boundary surface of the medium A and B is represented by following Formula (3).

  From equation (3), the greater the difference between the acoustic impedance Z1 of the medium A and the acoustic impedance Z2 of the medium B, the greater the reflectance S of the ultrasonic wave at the boundary surface between the media A and B, and the smaller the transmittance T. I understand. Therefore, at the boundary surface between such different media A and B, the signal intensity of the ultrasonic wave transmitted through the boundary surface is reduced by an amount corresponding to the increase in the reflectance S (transmittance T is small), resulting in an attenuated signal. Therefore, it is possible to detect each position of the front wall (blood vessel front wall) and the rear wall (blood vessel rear wall) of the blood vessel from the degree of attenuation. That is, the position where the signal attenuation is large is the incident direction position of the blood vessel front wall and the blood vessel rear wall.

Therefore, in the present embodiment, an attenuation correction value that is one of the attenuation feature values is calculated. FIG. 8 is a diagram showing a simple ultrasonic propagation model for explaining the calculation of the attenuation feature value. FIG. 8 shows a case where an ultrasonic wave having an incident signal intensity T ₁ is incident on the subject having a plurality of medium boundary surfaces 40 from the ultrasonic probe 16 in the right direction in FIG. However, there is no diffusion attenuation and absorption attenuation of ultrasonic waves.

The subject shown in FIG. 8 has a plurality of medium boundary surfaces 40 — i (i = 1, 2,...) So as to face the incident direction of the ultrasonic waves. The sound wave is reflected or transmitted by these medium boundary surfaces 40 and propagates. The reflectance S _i of the i-th medium boundary surface 40 — _i is determined by the acoustic impedance Z of the two mediums serving as the boundary according to the equation (2). The reception signal intensity (reflection intensity) R _i of the ultrasonic wave reflected from the i-th medium boundary surface 40 — _i is equal to the incident signal intensity (incident intensity) T _{i of the} ultrasonic wave incident on the medium boundary surface 40 — _i and the medium. It is obtained by the product of the reflectance S _i of the boundary surface 40 — _i (the following equation (4)).

In detail, the incident signal strength T ₁ of the the first medium interface 40_1 is incident signal strength T ₁ of the ultrasonic wave from the ultrasonic probe 16. The incident signal intensity T _i to the second and subsequent medium boundary surfaces 40 — i (i = 2, 3,...) Is the transmission of ultrasonic waves from the (i−1) th medium boundary surface 40 — (i−1). is the intensity, the incident signal strength _{T i-1} to the medium interface 40_ (i-1), obtained by the difference between the reflection intensity _{R i-1} from the medium interface 40_ (i-1) (the following formula (5)).

In other words, the incident signal strength _{T i} of each medium interface 40_i (i = 1, 2, · ·) can be expressed by the following equation (6).

The reflection intensity R _i from each of the medium boundary surfaces 40 — _i becomes the received signal intensity in the ultrasonic probe 16. At this time, the reception signal of the reflected wave from the i-th medium boundary surface 40_i is ultrasonicated by the medium boundary surface 40_j (j = 1, 2,..., I-1) up to the (i-1) -th medium. by entering signal strength T _i partially reflected in is decreased, the attenuated signal.

Now, when there is no previous medium boundary surface 40_j (j = 1, 2,..., I−1) for the i-th medium boundary surface 40_i, that is, the incident signal intensity T ₁ from the ultrasonic probe 16. Considering an ideal state in which the ultrasonic wave as it is is incident on the i-th medium boundary surface 40 — _i, the reflection intensity R _i from the medium boundary surface 40 — _i is expressed by the following equation (7).

However, since the actual reflection intensity R _i from the i-th medium boundary surface 40 — _i is expressed by Expression (4), it is smaller than the reflection intensity R _{i in the} ideal state due to scattering attenuation. Therefore, as shown in the following equation (8), multiplied by a predetermined attenuation correction value alpha _i of the actual reflection intensity R _i, and match the reflection intensity R _i of the ideal state.

From equation (8), the attenuation correction value α _i of the i-th medium boundary surface 40 — _i is expressed by the following equation (9).

Multiplying the actual reflection intensity R _i by the attenuation correction value α _i obtained as described above cancels the attenuation of the received signal at the corresponding medium boundary surface 40 — _i . Therefore, the attenuation correction value α _i indicates how much the actual reflection intensity (received signal intensity) R _i is smaller than the reflection intensity R _i in the ideal state on the medium boundary surface 40 — _i , that is, the attenuation correction value α _i . Represents the degree.

9 to 11 are graphs of attenuation correction values α _i relating to the respective scanning lines calculated from the A mode images relating to the respective scanning lines of the x-direction center scanning lines L311, L313 and L315 shown in FIGS. 5 to 7. FIG. 9 to 11, the horizontal axis is a sampling point set on the scanning line. In this example, a blood vessel 21 is present on each x-direction center scanning line L311, L313, L315. The x-direction center scanning line L313 is also the blood vessel center upper scanning line L323.

(1) Selection of the blood vessel center upper scanning line For example, referring to FIG. 10, the attenuation correction value α _i relating to the scanning line passing through the blood vessel 21 is determined by the incident direction position P431 of the blood vessel front wall and the light incident direction of the blood vessel rear wall. The value greatly increases at the position P433. If the scan line is a blood vessel center top scan line as shown in FIG. 10, the distance D43 between the incident direction positions P431 and P433 of the blood vessel front wall and blood vessel rear wall (the distance between the front and rear walls) corresponds to the blood vessel diameter. To do. Here, the distance between the front and rear walls is maximum on the blood vessel center upper scanning line. That is, the distances D411 and D451 between the front and rear walls obtained by the scanning line that does not pass through the blood vessel center as shown in FIGS. 9 and 11 are naturally shorter than the distance D43 between the front and rear walls in FIG. Therefore, the selection of the scanning line above the blood vessel center can be performed by selecting the scanning line that maximizes the distance between the front and rear walls for each element row. 12 to 14 are diagrams showing attenuation correction values α _i related to the scanning lines L321, L323, and L325 on the blood vessel center shown in FIGS. 5 to 7 selected for each element row R23 in FIG. 4. . The front-rear wall distances D413, D43, and D453 obtained by the blood vessel center upper scanning lines L321, L323, and L325 are used as the blood vessel diameter in the corresponding element row.

(2) Calculation of blood vessel diameter and blood vessel center position When the blood vessel center upper scanning line is selected, the blood vessel diameter and blood vessel center position of the blood vessel 21 are calculated from the respective incident direction positions of the blood vessel front wall and blood vessel rear wall. For this purpose, first, the position (front wall position) in the xyz space is obtained from the incident direction position of the blood vessel front wall, and the position (rear wall position) in the xyz space is obtained from the incident direction position of the blood vessel rear wall. The x coordinate can be obtained by multiplying the scanning line number in the column direction by the pitch of the element 171, and the y coordinate can be obtained by multiplying the row number by the pitch of the element 171. On the other hand, the z coordinate can be obtained by the following equation (10) using the sampling point of the incident direction position. In Expression (10), fs represents a sampling frequency [Hz], c represents a sound velocity [m / s], and k represents a sampling point.

  Subsequently, the distance between the obtained front wall position and rear wall position in the xyz space is used as the blood vessel diameter, and the midpoint thereof is calculated as the blood vessel center position. If the blood vessel center position can be calculated, the blood vessel center position is plotted on the xy plane to determine the blood vessel center line in the xy plane view. In the present embodiment, since the start point of the scanning line is a position in the living body surface facing each element 171, the xy plane view blood vessel center line represents the relative position of the blood vessel with respect to the element arrangement surface 17.

(3) Display of the relative position of the blood vessel relative to the element arrangement surface The relative position of the blood vessel is displayed on the display screen of the ultrasonic image. In the present embodiment, the yz plane view blood vessel center line obtained by plotting the blood vessel center position on the yz plane is also displayed on the display screen. FIG. 15 is a diagram illustrating a screen configuration example of an ultrasonic image display screen. As shown in FIG. 15, the display screen of the ultrasonic image includes a blood vessel relative position display unit W51, a yz plane view blood vessel position display unit W53, and an ultrasonic image display unit W55.

  First, the display of the blood vessel relative position display unit W51 is displayed in an xy plan view with the vertical axis in the x direction and the horizontal axis in the y direction in the frame 511 representing the element arrangement surface 17 with the scale described in the ultrasonic probe 16. This is done by showing the blood vessel center line 513. The display of the blood vessel relative position display unit W51 is a display showing the position of a predetermined organ (in this case, a blood vessel) in a plan view viewed from the incident direction of the ultrasonic wave. According to the display of the blood vessel relative position display unit W51, the blood vessel relative position with respect to the element arrangement surface 17 can be presented together with the scale described on the ultrasonic probe 16. Therefore, the user can select the blood vessel 21 of the target site under the ultrasound probe 16 that is actually attached to the subject 2 according to the positional relationship between the alphabetic scale and the numerical scale and the xy planar blood vessel center line 513. It is possible to easily grasp the traveling direction. For example, in the example of FIG. 15, the user intuitively and intuitively knows that the blood vessel 21 of the target site is traveling in the direction connecting the scales “B” and “4” described on the ultrasonic probe 16. It can be grasped instantly at a glance. According to this, the user can easily puncture the puncture needle as intended with respect to the traveling direction of the blood vessel 21 at the time of puncture, for example, by inserting the puncture needle at a position different from the target position, etc. Can prevent accidental puncture.

  Next, the display of the yz planar blood vessel position display unit W53 is performed by showing the yz planar blood vessel center line 531 with the vertical axis representing the z direction and the horizontal axis representing the y direction. The display of the yz plane view blood vessel position display unit W53 is an example of a display indicating the position of a predetermined organ (in this case, a blood vessel) in a cross section along the incident direction of the ultrasonic wave. According to the display of the yz plane view blood vessel position display unit W53, the user can easily grasp the position in the depth direction (z coordinate) of the blood vessel 21 of the target site that runs under the skin of the ultrasonic probe 16. .

  Next, the display of the ultrasonic image display unit W55 is performed by arranging and displaying ultrasonic images (slice images) obtained by ultrasonic measurement for each element array. Each ultrasonic image displayed on the ultrasonic image display unit W55 is an example of a display indicating the position of a predetermined organ (in this case, a blood vessel) in a cross section along the incident direction of the ultrasonic wave. In FIG. 15, three ultrasonic images are displayed on the ultrasonic image display unit W55, but the number of ultrasonic images to be displayed can be set as appropriate, and operations of the forward button / reverse button and scroll bar are performed. For example, the ultrasonic image to be displayed can be switched. In FIG. 15, the scanning direction of the element arrangement surface 17 corresponding to each of the three ultrasonic images displayed on the ultrasonic image display unit W55 is indicated by a dotted line in the frame 511 of the blood vessel relative position display unit W51.

[Function configuration]
FIG. 16 is a block diagram illustrating a functional configuration example of the image generation apparatus 10. The image generation apparatus 10 includes a processing device 30 and an ultrasonic probe 16. The processing device 30 includes an operation input unit 310, a display unit 320, a communication unit 340, and a processing unit 350 as an arithmetic processing unit. A storage unit 400.

  The ultrasonic probe 16 includes a plurality of ultrasonic elements 171 and transmits ultrasonic waves with a pulse voltage output from the processing device 30 (the ultrasonic measurement control unit 360 of the processing unit 350). Then, the reflected ultrasonic wave transmitted is received, and the received signal is output to the ultrasonic measurement control unit 360.

  The operation input unit 310 receives various operation inputs from the user and outputs an operation input signal corresponding to the operation input to the processing unit 350. It can be realized with a button switch, lever switch, dial switch, trackpad, mouse, etc.

  The display unit 320 is realized by a display device such as an LCD (Liquid Crystal Display), and performs various displays based on a display signal from the processing unit 350, for example, the display shown in FIG.

  The communication unit 340 is a communication device for transmitting / receiving data to / from the outside under the control of the processing unit 350. As a communication method of the communication unit 340, a wired connection via a cable conforming to a predetermined communication standard, a connection connected via an intermediate device that is also used as a charger, such as a cradle, or wireless communication is used. Various systems such as a wireless connection type can be applied.

  The processing unit 350 is, for example, a microprocessor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), an IC (Integrated Circuit) memory, or the like. Realized by electronic components. The processing unit 350 performs input / output control of data with each function unit, a predetermined program and data, an operation input signal from the operation input unit 310, and a reception signal of each element 171 from the ultrasonic probe 16. Based on the above, various arithmetic processes are executed to obtain biological information of the subject 2. Each unit constituting the processing unit 350 may be configured by hardware such as a dedicated module circuit.

  The processing unit 350 includes an ultrasonic measurement control unit 360, an image generation unit 370, and a relative position display control unit 376.

  The ultrasonic measurement control unit 360 constitutes the ultrasonic measurement unit 20 together with the ultrasonic probe 16, and ultrasonic measurement is performed by the ultrasonic measurement unit 20. For example, the ultrasonic measurement control unit 360 includes a drive control unit 361, a transmission / reception control unit 363, and a reception synthesis unit 365, and controls ultrasonic measurement in an integrated manner.

  The drive control unit 361 controls the transmission timing of the ultrasonic pulse from the ultrasonic probe 16 and outputs a transmission control signal to the transmission / reception control unit 363.

  The transmission / reception control unit 363 generates a pulse voltage according to the transmission control signal from the drive control unit 361 and outputs the pulse voltage to the ultrasonic probe 16. At that time, transmission delay processing is performed to adjust the output timing of the pulse voltage to each element 171. Further, the transmission / reception control unit 363 performs amplification and filter processing on the reception signal input from the ultrasonic probe 16 and outputs the processing result to the reception synthesis unit 365.

  The reception synthesizer 365 performs a delay process or the like as necessary, executes a process related to so-called focus of the received signal, and generates reflected wave data.

  The image generation unit 370 generates an ultrasonic image based on the result of the ultrasonic measurement by the ultrasonic measurement unit 20. The image generation unit 370 includes an attenuation feature value calculation unit 371, a differential value calculation unit 372, a threshold value determination unit 373, and a blood vessel diameter / blood vessel center calculation unit 374.

Attenuation characteristic value calculating unit 371, for each scan line in each element array, the incident signal strength T ₁ of the ultrasound from the ultrasonic probe 16, attenuation correction of the sampling point by using the received signal strength of each sampling point The value α _i is calculated.

The differential value calculation unit 372 differentiates the attenuation correction value α _i at each sampling point obtained by the attenuation feature value calculation unit 371 for each scanning line along the incident direction (direction of the scanning line).

The threshold determination unit 373 performs threshold determination on the differential value of the attenuation correction value α _i at each sampling point for each scanning line in each element row. And each incident direction position of the blood vessel front wall and the blood vessel rear wall is detected based on the determination result of the threshold determination. Thereby, detection of the position of a predetermined organ (in this case, blood vessels (anterior wall and outer wall)) in a plan view as seen from the incident direction of ultrasonic waves, and detection of the position of the organ in a cross section along the incident direction of ultrasonic waves Will be performed.

  The blood vessel diameter / blood vessel center calculation unit 374 calculates the front wall position and the rear wall position in the xyz space from the sampling points of the incident direction positions of the blood vessel front wall and the blood vessel rear wall, and obtains the blood vessel diameter and the blood vessel center.

  The relative position display control unit 376 performs control to display the relative position of the blood vessel with respect to the element arrangement surface 17.

  The storage unit 400 is realized by a storage medium such as an IC memory, a hard disk, or an optical disk. The storage unit 400 stores in advance a program for operating the image generation apparatus 10 and realizing various functions of the image generation apparatus 10, data used during the execution of the program, or the like. Is temporarily stored each time. The connection between the processing unit 350 and the storage unit 400 is not limited to a connection using an internal bus circuit in the apparatus, but may be realized by a communication line such as a LAN (Local Area Network) or the Internet. In that case, the storage unit 400 may be realized by an external storage device different from the image generation device 10.

  The storage unit 400 stores an image generation program 410, reflected wave data 420, attenuation characteristic value data 430, differentiation result data 440, and detection result data 450.

  The processing unit 350 reads out and executes the image generation program 410 to realize functions of the ultrasonic measurement control unit 360, the image generation unit 370, the relative position indication control unit 376, and the like. When these functional units are realized by hardware such as an electronic circuit, a part of a program for realizing the functions can be omitted.

  The reflected wave data 420 stores reflected wave data obtained by ultrasonic measurement. The A-mode image data 421 of the reflected wave data 420 stores the received signal intensity at each sampling point of each scanning line for each element array. The ultrasonic image data 423 stores image data of an ultrasonic image for each element array.

The attenuation feature value data 430 stores an attenuation correction value α _i calculated by the attenuation feature value calculation unit 371 for each sampling point of each scanning line for each element row. The differential result data 440 stores the differential value of the attenuation correction value α _i calculated by the differential value calculation unit 372 for each sampling point of each scanning line for each element row.

  The detection result data 450 includes the front wall position in the xyz space calculated by the blood vessel diameter / blood vessel center calculation unit 374 for each element row in which the incident direction positions of the blood vessel front wall and the blood vessel rear wall are detected by the threshold determination unit 373, and The rear wall position, the blood vessel diameter, and the blood vessel center position are stored for each element row.

[Process flow]
FIG. 17 is a flowchart showing a flow of ultrasonic image generation processing in the present embodiment. The processing described here can be realized by causing the processing unit 350 to read out and execute the image generation program 410 from the storage unit 400 and operate each unit of the image generation apparatus 10. Prior to measurement, the ultrasonic probe 16 is affixed and fixed to the body surface of the subject 2 by the user.

  First, the ultrasonic measurement unit 20 performs ultrasonic measurement and generates reflected wave data 420 (step S1).

Subsequently, the element column number (processing column number) M to be processed is initialized to “1” (step S3), and the scanning line number (processing scanning line number) N is initialized to “1” (step S5). Thereafter, the attenuation feature value calculation unit 371 performs a process of detecting the incident direction position of the puncture needle for each scanning line for the element row of the processing row number M. That is, first, the attenuation correction value α _i is calculated for each sampling point of the scanning line (processing scanning line) of the processing scanning line number N (step S7).

Then, the differential value calculation unit 372 differentiates the attenuation correction value α _i of the processing target line (step S9).

  Subsequently, the threshold determination unit 373 performs threshold determination on the differential value of each sampling point of the processing target line (step S11), and detects a sampling point that is equal to or greater than a predetermined determination threshold value, whereby the incident direction position of the blood vessel front wall is detected. And each incident direction position of the blood vessel rear wall is obtained (step S13). If it is obtained, the sampling point distance between each incident direction position is calculated (step S15). Thereafter, the processing scanning line number N is determined, and if it is not the scanning line number at the end in the scanning direction (step S17: NO), the processing scanning line number N is incremented and updated (step S19), and the process returns to step S7.

  On the other hand, when the processing scanning line number N is the scanning line number at the end in the scanning direction (step S17: YES), the blood vessel diameter / blood vessel center calculation unit 374 selects the scanning line with the maximum sampling point distance calculated in step S15. The processing column number M is selected as the blood vessel center upper scanning line (step S21). Subsequently, the blood vessel diameter / blood vessel center calculation unit 374 uses the sampling points of the incident direction positions of the blood vessel front wall and the blood vessel rear wall detected on the blood vessel center upper scan line, and the front wall position in the xyz space and The rear wall position is calculated (step S23). The blood vessel diameter / blood vessel center calculation unit 374 calculates the distance between the front wall position and the rear wall position as the blood vessel diameter (step S25), and calculates the midpoint between the front wall position and the rear wall position as the blood vessel center position. (Step S27).

  Thereafter, if the process column number M does not match the number of element columns of the element 171 (step S29: NO), the process column number M is incremented and updated (step S31), and the process returns to step S5. On the other hand, when the processing column number M matches the number of element columns of the element 171 (step S29: YES), the processing unit 350 displays an ultrasonic image display screen in which the ultrasonic images of the element columns are arranged. Control to be displayed on the unit 320 is performed (step S33). At this time, the relative position display control unit 376 displays the xy planar blood vessel center line obtained by plotting the blood vessel center position on the xy plane as information on the relative position of the blood vessel with respect to the element arrangement surface 17 on the display screen of the ultrasonic image. Is performed (step S35). In addition, control for displaying the yz planar blood vessel position and the cross-sectional image of the target site along the yz planar blood vessel centerline described later on the display screen of the ultrasonic image is appropriately performed.

  As described above, according to the present embodiment, the relative position (blood vessel relative position) of the blood vessel 21 with respect to the element arrangement surface 17 can be displayed and presented to the user. According to this, the user can easily grasp the traveling direction of the blood vessel 21 at the target site under the skin of the ultrasonic probe 16 actually attached to the subject 2.

  Note that the display screen of the ultrasonic image illustrated in FIG. 15 is an example, and the screen configuration may be changed as appropriate. FIG. 18 is a diagram illustrating another screen configuration example of the display screen. In the example of FIG. 18, the display screen of the ultrasonic image includes a blood vessel relative position display unit W511, a yz plan view blood vessel position display unit W53, an ultrasonic image display unit W55, and a blood vessel long-axis cross-section display unit W57.

  In the blood vessel relative position display unit W511 of this modification, the x-direction center line 515 and the xy plan view blood vessel center line 513 of the element arrangement surface 17 are formed in place of the scale attached to the blood vessel relative position display unit W51 of FIG. Display the angle. Further, a cross-sectional image of the target portion along the xy plan view blood vessel center line 513 is displayed on the blood vessel long-axis cross-section display portion W57. This cross-sectional image can be obtained by generating an ultrasonic image using an A-mode image related to the scanning line selected as the scanning line on the blood vessel center, and a long-axis cross-sectional image of the blood vessel 21 passing through the blood vessel center is rendered. Is done. This cross-sectional image is an example of an image showing the position of a predetermined organ (in this case, a blood vessel) in a cross section along the incident direction of ultrasonic waves.

In the above-described embodiment, the attenuation correction value α _i is calculated as the attenuation feature value. On the other hand, an attenuation intensity value β _i which is another attenuation feature value may be calculated, and the attenuation intensity value β _i may be used instead of the attenuation correction value α _i . The attenuation intensity value β _i is expressed by the following equation (11), and can be calculated from the ultrasonic incident signal intensity T ₁ from the ultrasonic probe 16 and the attenuation correction value α _i .

  In the above-described embodiment, a blood vessel is exemplified as the predetermined organ in the living body, but the organ targeted by the present invention is not limited to the blood vessel. An organ that is harder than the fat layer or muscle layer is suitable as a target. For example, a tubular organ, a lymph vessel, a bundle of nerve fibers, and the like can be targeted.

  DESCRIPTION OF SYMBOLS 10 ... Image generation apparatus, 16 ... Ultrasonic probe, 30 ... Processing apparatus, 310 ... Operation input part, 320 ... Display part, 340 ... Communication part, 350 ... Processing part, 360 ... Ultrasonic measurement control part, 361 ... Drive control 363... Transmission / reception control unit, 365... Reception synthesis unit, 370... Image generation unit, 371... Attenuation characteristic value calculation unit, 372... Differential value calculation unit, 373. 376 ... Relative position display control unit, 400 ... Storage unit, 410 ... Image generation program, 420 ... Reflected wave data, 430 ... Attenuation feature value data, 440 ... Differential result data, 450 ... Detection result data

Claims (8)

An image generation apparatus including an arithmetic processing unit that generates an ultrasonic image based on a reception signal received from a reflected wave of the ultrasonic wave incident on the living body,
The arithmetic processing unit is
Calculating an attenuation feature value at each position along the incident direction of the ultrasonic wave based on the received signal;
Detecting a position of a predetermined organ in the living body based on the attenuation feature value;
Displaying the position of the predetermined organ;
An image generation device that executes An ultrasonic probe in which the ultrasonic wave is incident and an ultrasonic element that receives the reflected wave is arranged in a planar shape,
The displaying includes displaying a relative position of the predetermined organ with respect to the ultrasonic element;
The image generation apparatus according to claim 1. The detecting is to detect a position of the predetermined organ in a plan view viewed from the incident direction of the ultrasonic wave.
The image generation apparatus according to claim 2. The detecting includes detecting a position of the predetermined organ in a cross section along an incident direction of the ultrasonic wave;
The image generation apparatus as described in any one of Claims 1-3. The arithmetic processing unit is
Calculating a differential value along the incident direction of the attenuation feature value;
And execute
The detecting is detecting a position of the predetermined organ based on a differential value of the attenuation feature value.
The image generation apparatus according to claim 4. The calculation of the attenuation feature value is to calculate an attenuation correction value for canceling the attenuation of the received signal using the incident signal intensity of the ultrasonic wave and the received signal intensity of the reflected wave. ,
The image generation apparatus as described in any one of Claims 1-5. The calculation of the attenuation characteristic value is to calculate the attenuation intensity value of the reception signal using the incident signal intensity of the ultrasonic wave and the reception signal intensity of the reflected wave.
The image generation apparatus as described in any one of Claims 1-5. An image generation method for generating an ultrasonic image based on a reception signal received from a reflected wave of an ultrasonic wave incident on a living body,
Calculating an attenuation feature value at each position along the incident direction of the ultrasonic wave based on the received signal;
Detecting a position of a predetermined organ in the living body based on the attenuation feature value;
Displaying the position of the predetermined organ;
An image generation method including:

Images