JP2008289632A - Ultrasonic diagnostic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide ultrasonic diagnostic equipment displaying an accurate ultrasonic image of an optional time phase. <P>SOLUTION: This ultrasonic diagnostic equipment 1 stores ultrasonic image information of biotissue of a subject transmitted from an ultrasonic probe 3 in a storage section 15. A tracking section 25 reads front/rear image information (frames) of a specified time phase from the storage section 15 and calculates a moving distance of a small region of image (ROI). An intermediate virtual frame calculation section 27 temporally and internally divides the front/rear image information of the specified time phase and calculates an intermediate virtual frame of a time phase equal to the time phase of the specified time phase. The intermediate display frame calculation section 29 spatially performs the internal division based on the calculated intermediate virtual frame and calculates the intermediate display frame with luminance information corresponding to pixel positions of the display section 17. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ultrasonic diagnostic apparatus that images and displays a biological tissue of a subject. More specifically, the present invention relates to an ultrasound diagnostic apparatus that displays and measures an ultrasound image of a living biological tissue.

  The ultrasonic diagnostic apparatus captures a tomographic image of a biological tissue of a subject and displays it on a display device. The medical staff uses the displayed tomographic image to diagnose the living tissue of the subject. For example, in the case of a cardiac or vascular circulatory system and other organs with movement, the movement of a living tissue constituting the organ is observed with a tomographic image to diagnose the function of the organ or the like.

  In the ultrasonic diagnostic apparatus, the minimum value of ultrasonic transmission / reception time is determined by the speed of ultrasonic waves. Usually, the repetition frequency (PRF) of an ultrasonic beam is 8 kHz, for example, and the frame rate of an ultrasonic tomographic image (B mode image) composed of 100 ultrasonic beams is 80 frames per second. In the ultrasonic image of the heart, there is a problem that when the movement of a fast moving tissue such as a mitral valve is captured and used as research or diagnostic information, the image is deteriorated due to insufficient time resolution.

  Conventionally, there is a method for solving the problem of insufficient time resolution by the aperture synthesis method. Aperture synthesis method reconstructs an ultrasonic tomographic image by irradiating a wide living body area without narrowing the transmitted beam and scanning the received beam within the transmitted beam to create multiple received beams in one transmission and reception. It is a method to do.

  In addition, there has been proposed an ultrasonic diagnostic apparatus that calculates a motion information image representing a displacement or distortion of a biological tissue such as a heart from a plurality of ultrasonic images having different time phases (see “Patent Document 1”).

JP 2003-175041 A

  However, the reconstruction of the ultrasonic tomographic image by the aperture synthesis method for solving the problem of insufficient time resolution has a limit in speeding up the signal because the transmission / reception signal is buried in noise.

  Even if the aperture synthesis method is used, in the ultrasonic image of the heart, the scanning time of the ultrasonic beam is different at the left end and the right end of the screen, and at the upper end and the lower end, respectively. A phase shift has occurred. Therefore, there is a problem in that the shape of a tissue that moves at high speed, such as a mitral valve, is displayed in a distorted manner, or the thickness of the left and right walls of the heart is displayed differently.

  In addition, the ultrasonic diagnostic apparatus according to “Patent Document 1” calculates the displacement and distortion of the movement of the living tissue based on the movement of the tracking points in the frames of a plurality of ultrasonic images. There is a problem in that the display of the distortion and size of the tissue shape caused by the time lag is not improved because the pixels in one frame of the ultrasonic image to be displayed are out of phase.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide an ultrasonic diagnostic apparatus capable of displaying an accurate ultrasonic image for an arbitrary time phase. is there.

  In order to achieve the above-described object, the present invention constructs an ultrasound image based on an ultrasound probe that transmits and receives ultrasound to and from a subject, and an ultrasound reception signal output from the ultrasound probe. In an ultrasonic diagnostic apparatus comprising: an image configuration unit; and a display device on which the configured ultrasonic image is displayed. Holding for storing the ultrasonic image as frame information in a storage device for each cross section of the subject Means for designating a time phase of an ultrasonic image to be displayed on the display device; and frame information reading for reading out frame information before and after the designated time phase designated by the time phase designating means from the storage device Means, intermediate frame calculation means for calculating intermediate frame information indicating an ultrasonic image of the designated time phase based on the read frame information before and after the designated time phase, and the calculated An ultrasonic diagnostic apparatus characterized by comprising an intermediate frame display means for displaying an ultrasonic image of the specified time phase on the display device on the basis of the between-frame information.

The frame information is ultrasonic image information obtained when an ultrasonic signal output from the ultrasonic probe scans a cross section of the subject. The frame information includes position information, luminance information, and time information for each pixel. In addition, since an ultrasonic image is obtained by scanning an object at the speed of ultrasonic waves, the time information values of the pixels of the frame information are different (the time phases are not aligned).
The intermediate frame information is position information and luminance information calculated in the designated time phase based on the frame information before and after the designated time phase. Therefore, the time phases of the pixels of the intermediate frame information are aligned.

  The ultrasonic diagnostic apparatus of the present invention holds an ultrasonic image as frame information for each cross section of the subject, and specifies the time phase of the ultrasonic image to be displayed on the display device. Based on the previous and next frame information, intermediate frame information indicating the designated time phase ultrasonic image is calculated, and the designated time phase ultrasonic image is displayed based on the intermediate frame information.

  As a result, an ultrasonic image with the same time phase can be displayed, so that an ultrasonic image with accurate shape and dimensional information can be obtained. Moreover, the reliability of diagnosis of the subject can be improved by the medical staff performing diagnosis using an accurate ultrasonic image.

  The ultrasonic diagnostic apparatus further includes a tracking unit that tracks the movement of the biological tissue of the subject between the frame information before and after the designated time phase. The intermediate frame calculation means divides the position information and luminance information of the frame information before and after the designated time phase in the time direction based on the movement amount acquired by the tracking means, and determines the position information and luminance information in the intermediate frame information. It may be calculated.

The tracking means designates a region of interest (ROI) for a predetermined biological tissue of the frame information, tracks the movement of the region of interest between the preceding and following frame information, and calculates the amount of movement of the region of interest It is. Image tracking processing such as a block matching method can be used for tracking the region of interest.
By dividing the preceding and succeeding frames in the time direction according to the designated time phase, the time phase of the intermediate frame information can be aligned with the designated time phase.

Further, the intermediate frame calculation means of the ultrasonic diagnostic apparatus internally divides the calculated position information and luminance information of the intermediate frame information in the spatial direction, and calculates luminance information at the intersection of the pixel lines in the intermediate frame information. Also good.
The intersection of the pixel lines is a coordinate position where the display device can display pixels. For example, an intersection of a horizontal pixel line and a vertical pixel line of the display device is defined as an intersection of pixel lines.
The intermediate frame information aligned with the specified time phase is divided in the spatial direction in accordance with the intersection of the pixel lines of the display device, and the luminance information of the intersection of the pixel lines can be calculated and displayed on the display device.

Further, the intermediate frame calculation means of the ultrasonic diagnostic apparatus may calculate the measurement information in the intermediate frame information based on the measurement information included in the frame information before and after the designated time phase.
Thereby, it is possible to display an accurate ultrasonic image and measurement information in which the time phase is aligned with the designated time phase for the region having the measurement information.

The ultrasonic diagnostic apparatus may acquire a biological signal of the subject, detect a predetermined time phase, and specify the detected predetermined time phase as a time phase of an ultrasonic image to be displayed on the display device.
As a result, the time phase can be automatically specified. In addition, a useful time phase such as a biological signal can be detected, and a useful ultrasound image in the time phase can be accurately acquired.

  ADVANTAGE OF THE INVENTION According to this invention, the ultrasonic diagnosing device which makes it possible to display an exact ultrasonic image about arbitrary time phases can be provided.

  Hereinafter, preferred embodiments of an ultrasonic diagnostic apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

(1. Configuration of the ultrasonic diagnostic apparatus 1)
First, the configuration of the ultrasonic diagnostic apparatus 1 will be described with reference to FIG.
FIG. 1 is a configuration diagram of the ultrasonic diagnostic apparatus 1.

  The ultrasonic diagnostic apparatus 1 is an apparatus that displays an ultrasonic image of a diagnostic region by transmitting ultrasonic waves to a subject and receiving reflected waves from a living tissue. The ultrasonic diagnostic apparatus 1 receives an ultrasonic probe 3 that transmits and receives ultrasonic waves, a transmission unit 5 that transmits a signal to the ultrasonic probe 3, and a signal acquired by the ultrasonic probe 3. Receiving unit 7, calculation unit 9 that performs processing such as ultrasonic image acquisition and measurement, operation unit 11 that is operated by an operator, timer signal generation unit 13 that provides time information to calculation unit 9, and acquisition The storage part 15 which memorize | stores ultrasonic image information, subject information, etc. which were performed, the display part 17 etc. which display the acquired ultrasonic image information are provided.

The ultrasonic probe 3 includes an ultrasonic transducer that converts an electrical signal into an ultrasonic wave. The ultrasonic probe 3 converts the electrical signal sent from the transmission unit 5 into ultrasonic waves using an ultrasonic transducer and transmits the ultrasonic signals to the subject. The ultrasonic probe 3 receives a reflected wave from the living tissue, converts it into an electrical signal by an ultrasonic transducer, and sends it to the receiving unit 7.
The transmission unit 5 is a device that generates an electrical signal for driving the ultrasonic transducer, and outputs a set delay time for the plurality of ultrasonic transducers to be driven.
The receiving unit 7 is a device that receives, amplifies, and digitizes an electrical signal obtained by converting an ultrasonic wave reflected from a living tissue by an ultrasonic transducer.

  The calculation unit 9 includes a CPU (Central Processing Unit) and a memory. The CPU loads a control program (not shown) stored in the storage unit 15 or the like into the memory and executes it. The calculation unit 9 includes a phasing addition unit 19, a visualization unit 21, a frame storage unit 23, a tracking processing unit 25, an intermediate virtual frame calculation unit 27, an intermediate display frame calculation unit 29, and the like.

The phasing adder 19 forms an ultrasonic reception beam by aligning and adding the phases of the digital signals sent from the receiver 7.
The visualization unit 21 performs processing for forming an ultrasonic image by imaging the signal of the ultrasonic reception beam formed by the phasing addition unit 19. The visualization unit 21 performs detection, logarithmic compression, and γ correction on the ultrasonic reception beam signal.

The frame storage unit 23 temporarily stores at least two frames of image information (frames) of the ultrasonic reception beam signal visualized by the visualization unit 21. For example, the latest frame and a frame acquired immediately before it, or a frame that goes back several frames from the latest frame are stored. The image information for one screen of the ultrasonic reception beam signal will be described as one frame. The frame storage unit 23 may store the frame in the storage unit 15.
The tracking processing unit 25 calls the two frames stored by the frame storage unit 23, divides the frame whose time phase is earlier into image blocks of a predetermined small area, and moves each image block to another frame. Is calculated.

The intermediate virtual frame calculation unit 27 performs internal division in the time direction based on the two frames stored in the frame storage unit 23 and the movement destination of the image block of the small area calculated by the tracking processing unit 25. An intermediate virtual frame with the same time phase is calculated.
The intermediate display frame calculation unit 29 reconstructs an intermediate display frame for displaying an ultrasonic image on the display unit 17 based on the intermediate virtual frame having the same time phase calculated by the intermediate virtual frame calculation unit 27.
The operation unit 11 is an input device such as a keyboard, a mouse, a trackball, and a touch panel arranged in the ultrasonic diagnostic apparatus 1. The operator operates the operation unit 11 to perform an ultrasonic image acquisition operation by the ultrasonic apparatus 1, an instruction for a measurement operation, input of information, and the like.

  The timer signal generator 13 supplies time information to the calculator 9. The timer signal generator 13 generates a timing for calculating and displaying a reconstructed frame having the same time phase.

  The storage unit 15 is, for example, a hard disk, a general-purpose memory, a frame memory, or the like. The storage unit 15 stores the acquired ultrasonic image information (frame), subject information, control program, and the like.

  The display unit 17 is a CRT or a liquid crystal display device. The display unit 17 displays the acquired ultrasonic image information, the intermediate display frame calculated by the intermediate display frame calculation unit 29, measurement information, subject information, and the like.

(2. Ultrasound image reconstruction processing)
Next, ultrasound image reconstruction processing will be described with reference to FIGS.
(2-1. Overview of reconstruction processing of ultrasonic image)
First, an outline of an ultrasound image reconstruction process will be described with reference to FIGS. 2 and 3.
FIG. 2 is a flowchart showing a procedure for reconstructing an ultrasound image.
FIG. 3 is a diagram illustrating reconstruction of an ultrasound image.

  When starting the examination of the subject, the operator operates the operation unit 11 to perform an instruction operation to display an image having the same time phase. When the operator operates the operation unit 11 and applies the ultrasonic probe 3 to the subject to instruct acquisition of an ultrasonic image of the living tissue, the ultrasonic diagnostic apparatus 1 starts acquiring the ultrasonic image. (Step 1001).

  The transmission unit 5 (FIG. 1) of the ultrasonic diagnostic apparatus 1 obtains an ultrasonic image acquisition instruction from the calculation unit 9 and sends it to the ultrasonic probe 3. The ultrasonic probe 3 converts the electrical signal sent from the transmission unit 5 into an ultrasonic wave and ejects the ultrasonic wave to the subject. In the process of propagating in the living body of the subject, the ultrasonic wave is partially reflected at the tissue boundary surface with different acoustic impedance in the living body, and the reflected wave returns to the ultrasonic probe 3. Come. The reflected wave sequentially returns to the ultrasonic probe 3 as the ultrasonic wave transmitted from the shallow part to the deep part in the living body propagates. The ultrasonic probe 3 receives the reflected wave from the living tissue, converts it into an electrical signal, and sends it to the receiving unit 7.

The receiver 7 amplifies the electrical signal sent from the ultrasound probe 3, converts it into a digital signal, and sends it to the phasing adder 19.
The phasing adder 19 aligns and adds the phases of the digital signals sent from the receiver 7 to form an ultrasonic reception beam signal. Further, the phasing / adding unit 19 has a function of reducing unnecessary noise and a filtering processing function to obtain a signal in a necessary region.

  The visualization unit 21 performs image processing on the ultrasonic reception beam signal formed by the phasing addition unit 19 by performing signal processing such as detection, logarithmic compression, and γ correction, and generates an ultrasonic image. Since one frame is an ultrasonic image for one screen of the ultrasonic reception beam signal, there is a time phase shift in the time information of each pixel constituting one frame.

The frame storage unit 23 stores each frame of the ultrasonic image imaged by the visualization unit 21 in the storage unit 15 (step 1002). Alternatively, the frame storage unit 23 may store a plurality of predetermined frames.
Next, the operator, time phase of the ultrasonic image, to specify a time phase _{t 2} for example (step 1003). Operator input device of the operation unit 11, for example, GUI, such as the slider operation by operating the (Graphical User Interface) or mechanical dial may be performed input time phases _{t 2.} Also, the time phase t ₂ may be programmed in advance and generated by the timer signal generator 13.

Tracking processing unit 25 (FIG. 1) reads the front and rear frames 31 and the frame 33 of the phase _{t 2} when a specified from the storage unit 15 (step 1004).

Before the detailed description of the tracking processing unit 25, with reference to FIG. 3 will be briefly described reconstruction of an ultrasound image in a phase t ₂ when specified.
FIG. 3 is a diagram illustrating reconstruction of an ultrasound image.
FIG. 3 shows an intermediate virtual in which the temporal phase of the frame 31 and the frame 33 before and after the designated time phase (t ₂ ) and the frame 31 and the frame 33 are divided in time and the time phases are aligned at the designated time phase (t ₂ ). An intermediate display frame 37 obtained by dividing the frame 35 and the intermediate virtual frame 35 in the spatial direction is shown. The coordinate axis “t” indicates a time phase. The coordinate axis “θ” and the coordinate axis “r” indicate the scanning position of the ultrasonic beam, which will be described later. “I” is luminance information using “θ”, “r”, and “t” as parameters.

Frame 31 of the previous phase t ₂ when specified, includes a time phase of the time t _0S, time phase of each pixel constituting the frame 31 is different. For example, the time phase of the point 300 that is the representative point of the ROI 303 on the frame 31 is t ₀ .
Frame 33 after the phase t ₂ when specified, includes a time phase of the time t _1S, time phase of each pixel constituting the frame 33 is different. Time phase point 301 is a representative point of ROI304 on the frame 33 is _{t 1.}

Returning to the flowchart of FIG. 2, the tracking processing unit 25 divides the frame 31 into a plurality of attention regions (hereinafter referred to as ROIs), and tracks, for example, the movement position of the ROI 303 to the frame 33 (step 1005). In order to obtain the movement position of the ROI 303, image correlation processing such as a block matching method may be used.
The ROI 304 that is the movement position of the ROI 303 in the frame 31 to the frame 33 is obtained as a result of the tracking process.

  The tracking processing unit 25 may determine that the ROI having a low correlation is an unnecessary image such as noise as a result of the tracking process, and reduce the luminance information of the corresponding portion. By this processing, the contrast of the display of the living tissue with respect to the unnecessary image can be increased, and a clear ultrasonic image can be obtained.

Next, the intermediate virtual frame calculation unit 27 (FIG. 1) calculates the intermediate virtual frame for the designated time phase t ₂ based on the movement position of the ROI 303 of the frame 31 calculated by the tracking processing unit 25 to the frame 33. The frame 35 is calculated (step 1006). Intermediate virtual frame 35 includes a ROI303 frame 31, the position information and the luminance information of ROI304 moving the position of the frame 33 of the ROI303, is calculated by performing a time direction within minutes in time phase _{t 2.} Details of the calculation of the intermediate virtual frame 35 will be described later.

  Next, the intermediate display frame calculation unit 29 (FIG. 1) calculates an intermediate display frame 37, which is a display frame, based on the intermediate virtual frame 35 calculated by the intermediate virtual frame calculation unit 27 (step 1007). The intermediate display frame 37 is calculated as information to be displayed on the display unit 17 based on the intermediate virtual frame 35. The intermediate display frame 37 is calculated by dividing the pixels of the intermediate virtual frame 35 in the spatial direction. Details of the calculation of the intermediate display frame 37 will be described later.

Ultrasonic diagnostic apparatus 1, based on the intermediate display frame 37 displays the ultrasonic image in the phase t ₂ when specified to the display unit 17 (step 1008).

(2-2. Within the time direction)
Next, the internal part in the time direction of the sector image 39 will be described with reference to FIGS. However, in FIG. 5, the ROI tracking process is not performed, and the internal part in the time direction will be described by taking the point of the same position information as an example.

FIG. 4 is a diagram showing a sector image 39.
FIG. 4 shows a sector image 39 obtained by fan-shaped ultrasonic scanning. An ultrasonic scanning beam 41 transmitted from the ultrasonic probe 3 has a scanning beam angle (θ) 43 and a scanning beam depth (r) 45 with respect to the living tissue of the subject, for example, at the right end (scanning start point). Scan in the beam scanning direction 47 from the left to the left end (scan end point).

A point 49 indicates scanning information at a position of a predetermined scanning beam angle (θ) and a predetermined scanning beam depth (r). The point 49 has time information (t ₀ ) (FIG. 5) and luminance information in addition to the position information (θ, r).

FIG. 5 is a diagram illustrating calculation of the intermediate virtual frame 35.
FIG. 5 is a diagram showing the relationship between the time t of the point indicated by the scanning beam 41 and the azimuth position θ at a predetermined scanning beam depth (r) 45 of the sector image 39. The scanning beam 41 scans from the right end (scanning start point) to the left end (scanning end point) to acquire the frame 31, and the next scanning beam 41 acquires the frame 33. The scanning information acquired by the scanning beam 41 gradually shifts in time as it scans from the right end (scanning start point) to the left end (scanning end point).

For example, the point 49 of the frame 31 is at a predetermined azimuth position (θ), and the time phase of the point 49 is time t ₀ . In the frame 33 by the scanning of the next scanning beam 41, time phase of 50 points in the same azimuthal position as the point 49 of the frame 31 (theta) is the time t _1.

When calculating the intermediate virtual frame 35 having the same time phase at a predetermined time t ₂ , for example, at a predetermined azimuth direction position (θ), points 49 and 33 from the frames 31 and 33 that are the frames before and after the time t ₂ , respectively. Point 50 is extracted. The luminance information of the point 51 on the intermediate virtual frame 35 is obtained by using the change in the luminance information value from the point 49 to the point 50 and the value obtained by internally dividing the difference between the time t ₀ and the time t ₁ at the time t _2. Calculate (in the time direction). For all points of the frame 31 (or regions), by calculating the luminance information of the time t ₂ is a predetermined time phase, it is possible to calculate the intermediate virtual frame 35 having a uniform time phases for all the pixels.

  In FIG. 5, it is assumed that the points 49 and 50 of the frame 31 and the frame 33 are points at the same scanning beam angle (θ) and the same scanning beam depth (r), that is, position information is the same. explained.

(2-3. Calculation procedure of intermediate virtual frame 35)
Next, the procedure for calculating the intermediate virtual frame 35 (details of step 1006 in FIG. 2) will be described with reference to FIGS. Intermediate virtual frame 35 is a frame time phase t ₂ in time phase are satisfied, is calculated by the frame 31 and the frame 33 is around the frame of the time phase t ₂ based.

FIG. 6 is a flowchart showing the calculation procedure of the intermediate virtual frame 35.
In step 1005 (FIG. 2), the tracking processing unit 25 of the ultrasonic diagnostic apparatus 1 obtains the ROI 304 that is the movement position of the ROI 303 in the frame 31 to the frame 33 as a result of the tracking process.

  The intermediate virtual frame calculation unit 27 calculates position information and luminance information of a point 300 representing the ROI 303 in the frame 31 and a point 301 representing the ROI 304 in the frame 33, respectively. The position information of the point representing the ROI may be calculated as the center coordinates of the ROI. Further, the luminance information of the point representing the ROI may be calculated as the average luminance of the ROI.

For example, in FIG. 3, the position information of the point 300 representing the ROI 303 is calculated as the center coordinates (θ ₀ , r ₀ ) of the ROI, and the luminance information is calculated as the average luminance I ₀ of the ROI 303. The luminance I ₀ is expressed as I ₀ (θ ₀ , r ₀ , t ₀ ) as a value related to the position information (θ ₀ , r ₀ ) and the time information t ₀ . Similarly, the position information of the point 301 representing the ROI 304 is calculated as the center coordinates (θ ₁ , r ₁ ) of the ROI, and the luminance information is calculated as the average luminance I ₁ of the ROI 304. The luminance I ₁ is expressed as I ₁ (θ ₁ , r ₁ , t ₁ ).

The intermediate virtual frame calculation unit 27 calculates a movement vector connecting the movement source point 300 and the movement destination point 301 (step 2001 in FIG. 6). A point 302 of the movement vector at time phase t ₂ is calculated as one of the points constituting the intermediate virtual frame 35. Let the luminance information of the point 302 be I ₂ (θ ₂ , r ₂ , t ₂ ).

The intermediate virtual frame calculation unit 27 calculates the temporal direction internal ratio A of the time phase t ₂ specified for the movement vector (step 2002).
A = (t ₂ −t ₀ ) / (t ₁ −t ₀ ) (1)

Next, the intermediate virtual frame calculation unit 27 calculates the position information of the point 302 from the movement vector and the temporal direction internal ratio A (step 2003). That is, the position information θ ₂ and r ₂ are calculated as follows.
θ ₂ = θ ₀ + A × (θ ₁ −θ ₀ ) (2)
r ₂ = r ₀ + A × (r ₁ −r ₀ ) (3)

Next, the intermediate virtual frame calculation unit 27 calculates the luminance information of the point 302 from the movement vector and the temporal direction internal ratio A (step 2004). That is, the luminance information I ₂ is calculated as follows.
I ₂ = I ₀ + A × (I ₁ −I ₀ ) (4)
The luminance information I ₀ and the luminance information I ₁ are the average luminance values of the ROI 303 and the ROI 304, respectively. However, the luminance information I ₀ and the luminance information I ₁ are respectively the luminance of the central coordinates (θ ₀ , r ₀ ) of the ROI 303 and The brightness of the center coordinates (θ ₁ , r ₁ ) of the ROI 304 may be used.

The intermediate virtual frame calculation unit 27 repeats the processing from step 2001 until the calculation of the position information and luminance information of the point 302 is completed for all the small regions (ROI 303) obtained by dividing the frame 31 (NO in step 2005). .
When the position information and luminance information of the point 302 are calculated for all the small regions (ROI 303) obtained by dividing the frame 31, the intermediate virtual frame calculation unit 27 obtains the intermediate virtual frame 35 (step 2005) (step 2005). 2006).

Incidentally, each of the small regions obtained by dividing a frame 31 (ROI303), because each time phase is shifted, the time information _{t 0} of the center coordinates of each ROI is different. Similarly, the time information _{t 1} of the center coordinates of each ROI304 differ. Therefore, the time direction internal ratio A calculated in step 2002 differs for each ROI 303.

(2-4. Calculation procedure of intermediate display frame 37)
Next, the calculation procedure of the intermediate display frame 37 (details of step 1007 in FIG. 2) will be described with reference to FIGS.
The intermediate display frame calculation unit 29 (FIG. 1) calculates an intermediate display frame 37 that can be displayed on the display unit 17 based on the position information and luminance information of the pixel (point 302) calculated as the intermediate virtual frame 35. . That is, the intermediate display frame calculation unit 29 calculates the luminance information of the intersection of the horizontal direction pixel line and the vertical direction pixel line of the display device which is the display unit 17.

FIG. 7 is a flowchart showing a procedure for calculating the intermediate display frame 37.
The ultrasound diagnostic apparatus 1 obtains the intermediate virtual frame 35 by the process of step 1006 by the intermediate virtual frame calculation unit 27. Intermediate virtual frame 35 was calculated by the front and rear frames 31 and the frame 33 of the time phase t ₂ based on a frame of uniform time phase t ₂ in a time-phase.

FIG. 8 is a diagram illustrating the intermediate virtual frame 35.
The pixel line 57-1 and the pixel line 57-2 indicate line positions where the display device 17 can display pixels, and correspond to a horizontal pixel line and a vertical pixel line of the display device. In FIG. 8, the axis indicating the scanning beam angle (θ ₃ ) is the pixel line 57-1, and the axis indicating the scanning beam depth (r ₃ ) is the pixel line 57-2. The pixel line 57-1 and the pixel line 57-2 do not have to be orthogonal. Further, the pixel line 57-1 and the pixel line 57-2 are not limited to straight lines.

  Points 51-1 to 51-4, etc. are points indicating scanning information constituting the intermediate virtual frame 35 calculated in step 1006, and each have position information and luminance information.

Returning to the flowchart of FIG. First, the intermediate display frame calculation unit 29 selects a point 53 that is an intersection of the pixel line 57-1 and the pixel line 57-2 as a luminance information calculation point (step 3001). The point 53 is position information (θ ₃ , r ₃ ).

Next, the intermediate display frame calculation unit 29 extracts points 51-1 to 51-4 in the vicinity region 55 of the point 53. The luminance information of the pixels at the points 51-1 to 51-4 is represented by I _a (θ _a , r _a ), I _b (θ _b , r _b ), I _c (θ _c , r _c ), I _d ( θ _d , r _d ). The intermediate display frame calculation unit 29 obtains the spatial division ratio based on the position information of a plurality of points near the selected point 53, and uses the spatial division ratio and the luminance information of the plurality of points to calculate the point 53. Luminance information is calculated (step 3002, step 3003).

An example of a method for calculating the luminance information of the point 53 will be specifically described.
FIG. 9 is a diagram showing the creation of the intermediate display frame 37.
FIG. 9A shows the intermediate virtual frame 35. In the intermediate virtual frame 35 in FIG. 9A, not all intersections of the pixel lines 57 have luminance information, and any luminance information is used as the luminance information of the intersections of the pixel lines 57. The image quality deteriorates. FIG. 9B shows the intermediate display frame 37. The luminance information at the intersection of the pixel lines 57 of the intermediate display frame 37 is calculated based on the intermediate virtual frame 35. The intermediate display frame 37 is a frame having luminance information at the intersection of the pixel lines 57.

9 (a), the straight line and the intersection of the axis _{r 3} the intersection of the straight line and the axis theta ₃ connecting the point 51-1 and the point 51-2 54-1, connecting point 51-2 and the point 51-3 the 54-2, points 51-3 and the point 51-4 54-3 the intersection of the straight line and the axis theta ₃ connecting the tied point 51-4 and the point 51-1 the intersection of the straight line and the axis _{r 3} 54 -4. In addition, the pixel luminance values of the points 54-1 and 54-3 are I _e (θ ₃ , r _e ) and I _f (θ ₃ , r _f ), respectively.

The spatial direction internal ratio B1 of the point 54-1 between the point 51-1 and the point 51-2 is:
B1 = (θ ₃ −θ _a ) / (θ _b −θ _a ) (5)
It is. Accordingly, the r-coordinate r _e of the point 54-1 is calculated as follows.
r _e = r _a + B1 × (r _b −r _a ) (6)
Accordingly, the luminance information _{Ie at the} point 54-1 is calculated as follows.
I _e = I _a + B1 × (I _b −I _a ) (7)

Next, the spatial direction internal ratio B2 of the point 54-3 by the point 51-4 and the point 51-3 is
B2 = (θ ₃ −θ _d ) / (θ _c −θ _d ) (8)
It is. Accordingly, the r coordinate r _f of the point 54-3 is calculated as follows.
r _f = r _d + B2 × (r _c −r _d ) (9)
Therefore, the luminance information _If of the point 54-3 is calculated as follows.
I _f = I _d + B2 × (I _c −I _d ) (10)

Next, the spatial direction internal ratio B3 of the point 53 by the point 54-1 and the point 54-3 is
B3 = (r ₃ −r _e ) / (r _f −r _e ) (11)
It is. Therefore, luminance information I ₃ at point 53 is calculated as follows.
I ₃ = I _e + B3 × (I _e −I _f ) (12)

In this way, the intermediate display frame calculation unit 29 calculates the luminance information I ₃ of the point 53 on the intersection of the pixel lines 57 using the luminance information of the pixels of the points 51-1 to 51-4.
The intermediate display frame calculation unit 29 repeats the processing from step 3001 until the calculation of the luminance information is completed for all the intersections of the pixel lines 57 of the intermediate virtual frame 35 (NO in step 3004).
When the luminance information is calculated for all the intersections of the pixel lines 57 of the intermediate virtual frame 35 (YES in step 3004), the intermediate display frame calculating unit 29 obtains the intermediate display frame 37 (FIG. 9B) (step 3005). ).

The method of calculating the luminance information I ₃ at point 53 on the intersection of pixel line 57 may be a method of utilizing spatial direction internal ratio according to point 54-2 and the point 54-4 in FIG. 9 (a). Further, the number of reference points near the point 53 on the intersection is not limited to the four points described above.

  As described above, since the ultrasonic diagnostic apparatus 1 can display images having the same time phase, it can display an accurate ultrasonic image of a moving organ such as the heart.

(2-5. Display of ultrasonic image)
10 and 11 are diagrams showing an ultrasound image of the heart left ventricle 61 of the heart.
As shown in FIG. 10A, in the ultrasonic image 59a acquired by the conventional ultrasonic diagnostic apparatus, the movement of the mitral valve 63a is fast, so the shape of the mitral valve 63a is distorted and displayed. On the other hand, as shown in FIG. 10B, the ultrasonic image 59b acquired by the ultrasonic diagnostic apparatus 1 of the present invention can display the exact shape of the mitral valve 63b with the same time phase.

  As shown in FIG. 11 (a), in the ultrasound image 65a acquired by the conventional ultrasound diagnostic apparatus, the myocardial wall 67 is moving and at the same time the left and right positions of the scanning beam 41 are different in time phase. The widths of the myocardial wall 67-1 and the myocardial wall 67-2 are not accurately displayed. On the other hand, as shown in FIG. 11B, in the ultrasonic image 65b acquired by the ultrasonic diagnostic apparatus 1 of the present invention, the shapes of the accurate myocardial wall 69-1 and myocardial wall 69-2 having the same time phase are obtained. Can be displayed.

The ultrasonic diagnostic apparatus 1 of the present invention can reconstruct and display an ultrasonic image of an arbitrary time phase. Moreover, the ultrasonic diagnostic apparatus 1 of the present invention can display an ultrasonic image of an arbitrary time phase and perform image measurement or the like.
Note that the ultrasonic diagnostic apparatus 1 of the present invention may set the time phase at the timing when a timer signal is sent from the timer signal generator 13 to the calculator 9 to create and display a reconstructed image. Further, the time phase for displaying an image may be programmed in advance in the execution program.

(3. Other embodiments)
Next, an ultrasonic diagnostic apparatus 1b according to another embodiment will be described with reference to FIG.
FIG. 12 is a configuration diagram of the ultrasonic diagnostic apparatus 1b. An ultrasonic diagnostic apparatus 1b according to FIG. 12 has a configuration in which the visualization unit 21 of the ultrasonic diagnostic apparatus 1 shown in FIG. The measurement value calculation unit 71 outputs an image that visualizes a colorized Doppler signal distribution, a luminance distribution time-change image in an arbitrary direction, a change in myocardial wall thickness due to image tracking, and the like.

  Thus, in the ultrasonic diagnostic apparatus 1b, it is possible to display the measurement result image with the same time phase for the measurement result images having different time phases. Therefore, the medical staff can obtain an accurate measurement result image having the same time phase, and can improve the reliability of diagnosis.

Next, the ultrasonic diagnostic apparatus 1c will be described with reference to FIG.
FIG. 13 is a configuration diagram of the ultrasonic diagnostic apparatus 1c. An ultrasonic diagnostic apparatus 1c according to FIG. 13 is obtained by adding the configuration of a biological signal acquisition unit 73 and a reconstruction time phase detection unit 75 to the ultrasonic diagnostic apparatus 1 shown in FIG.

  The biological signal acquisition unit 73 is a biological signal acquisition device that acquires biological signals such as an electrocardiogram signal and a heart sound signal. The reconstruction time phase detection unit 75 identifies a time phase useful for the examiner from the signal obtained from the biological signal acquisition unit 73 in order to reconstruct an ultrasound image having the same time phase, and sends it to the calculation unit 9. It is a device that outputs.

  By adopting such a configuration, the ultrasonic diagnostic apparatus 1c can display the time phase of the ultrasonic image in synchronization with a signal emitted from the living body. Further, it is possible to display an image of a time phase that the examiner wants to pay attention to. In addition, a reconstructed video of a predetermined time phase section can be displayed. Therefore, for example, it is possible to obtain an ultrasound image useful for observing a pathological condition by limiting the time phase relating to the heart operation such as blood regurgitation, valve opening / closing, and arrhythmia.

(4. Other)
The ultrasonic diagnostic apparatus of the present invention can reduce image degradation due to insufficient time resolution of ultrasonic waves. In particular, in the case of a moving organ such as a heart, an accurate ultrasonic image of a living tissue having the same time phase can be displayed, which has an effect of improving the reliability of medical diagnosis by a medical worker.
In addition, since an ultrasonic image having the same time phase can be displayed for an arbitrary time phase and image measurement can be performed, a reliable and accurate measurement value can be obtained.

  In addition, as a result of the ROI tracking process, the ultrasonic diagnostic apparatus of the present invention determines the ROI having low correlation as noise and lowers the brightness, thereby increasing the display contrast of the ultrasonic image and improving the visibility of the biological tissue region. Can be made.

Note that the ultrasonic diagnostic apparatus of the present invention can display not only a still image of a living tissue but also a moving image having a uniform time phase. For example, by providing a signal having a constant frequency from the timer signal generation unit 13 to the calculation unit 9, it is possible to reconstruct an image having a uniform time phase for each timer signal and display a moving image.
The ultrasonic diagnostic apparatus of the present invention is not limited to a two-dimensional ultrasonic image and can be applied to a three-dimensional ultrasonic image.

  The technical scope of the present invention is not limited to the embodiment described above. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.

Configuration diagram of the ultrasonic diagnostic apparatus 1 Flow chart showing the procedure for reconstruction of ultrasound image Diagram showing reconstruction of ultrasound image The figure which shows the sector image 39 The figure which shows calculation of the intermediate | middle virtual frame 35 A flowchart showing a calculation procedure of the intermediate virtual frame 35 Flow chart showing creation of intermediate display frame 37 The figure which shows the intermediate | middle virtual frame 35 The figure which shows creation of the intermediate display frame 37 The figure which shows the ultrasonic image of the mitral valve 63 The figure which shows the ultrasonic image of the myocardial wall 67 Configuration diagram of ultrasonic diagnostic apparatus 1b Configuration diagram of ultrasonic diagnostic apparatus 1c

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1b, 1c ......... Ultrasonic diagnostic apparatus 3 ......... Ultrasonic probe 5 ......... Transmission part 7 ......... Reception part 9 ......... Calculation part 11 ......... Operation part 13 ......... Timer Signal generation unit 15... Storage unit 17... Display unit 19... Phasing addition unit 21... Visualization unit 23... Frame storage unit 25. Calculation unit 29... Intermediate display frame calculation unit 31, 33... Frame 35... Intermediate virtual frame 37... Intermediate display frame 39... Sector image 41 ... Scanning beam 43. Angle (θ)
45 ... Scanning beam depth (r)
47... Beam scanning direction 49, 50, 51, 51-1 to 51-4, 53, 54-1 to 54-4, 300, 301, 302. -2 ......... Pixel line 59, 65 ..... Ultrasound image 61 .... Left heart chamber 63 .... Mitral valve 69-1, 69-2 .... Myocardial wall 71 .... Measurement value calculation unit 73... Reconstruction time phase detection unit 75... Biosignal acquisition units 303 and 304.

Claims (5)

An ultrasound probe that transmits and receives ultrasound to and from the subject, an image configuration unit that configures an ultrasound image based on an ultrasound reception signal output from the ultrasound probe, and the configured ultrasound image An ultrasonic diagnostic apparatus comprising: a display device on which is displayed;
Holding means for holding the ultrasonic image as frame information in a storage device for each cross section of the subject;
Time phase designation means for designating a time phase of an ultrasonic image to be displayed on the display device;
Frame information reading means for reading frame information before and after the designated time phase designated by the time phase designation means from the storage device;
Intermediate frame calculation means for calculating intermediate frame information indicating an ultrasonic image of the designated time phase based on the read frame information before and after the designated time phase;
Intermediate frame display means for displaying the ultrasonic image of the designated time phase on the display device based on the calculated intermediate frame information;
An ultrasonic diagnostic apparatus comprising: Tracking means for tracking movement of the biological tissue of the subject between frame information before and after the specified time phase;
The intermediate frame calculating unit divides the position information and luminance information of the frame information before and after the designated time phase into the time direction based on the movement amount acquired by the tracking unit, and the position information in the intermediate frame information The ultrasonic diagnostic apparatus according to claim 1, wherein brightness information is calculated.   The intermediate frame calculation means calculates the luminance information on the intersection of the pixel lines in the intermediate frame information by dividing the position information and luminance information of the calculated intermediate frame information in the spatial direction. The ultrasonic diagnostic apparatus according to claim 1 or 2.   The intermediate frame calculation means calculates the measurement information in the intermediate frame information based on measurement information included in frame information before and after the designated time phase. An ultrasonic diagnostic apparatus according to 1. A biological signal acquisition means for acquiring a biological signal of the subject;
Time phase detecting means for detecting a predetermined time phase from the acquired biological signal;
Comprising
5. The super phase according to claim 1, wherein the time phase designating unit designates the detected predetermined time phase as a time phase of an ultrasonic image to be displayed on the display device. Ultrasonic diagnostic equipment.

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