JP2006326178A - Ultrasonic diagnostic apparatus and ultrasonic diagnostic program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide ultrasonic diagnostic apparatus which presents a high-quality luminance value holding image by correcting raising of average luminance of the whole image occurring with maximum value holding arithmetic about luminance. <P>SOLUTION: The ultrasonic diagnostic apparatus 10 which generates the luminance value holding image by carrying out the maximum value holding arithmetic about luminance using a plurality of B-mode images generated based on an echo signal from a P is provided with: an internal storage device 29 storing a gain correction table for designating a gain correction value according to time for carrying out the maximum value holding arithmetic; and an image processing circuit 25c for correcting a gain according to the gain correction value designated by the gain correction table. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasound capable of presenting, as diagnostic information, a micro blood flow circulation at a capillary level and a fine structure of blood vessel blood flow faster than the capillaries in contrast imaging performed using an ultrasound contrast agent. The present invention relates to a diagnostic apparatus and an ultrasonic diagnostic program.

  Ultrasonic diagnostic equipment provides real-time display of heart pulsation and fetal movement with simple operation by simply placing an ultrasonic probe on the body surface. Compared to diagnostic equipment such as X-ray, CT, MRI, etc. It has the features that it can be used in obstetrics and home medical care, etc. because it has a small scale, can be easily inspected even when moved to the bedside, and is not affected by exposure like X-rays. Yes.

  By the way, in recent years, intravenous administration type ultrasonic contrast agents have been commercialized, and contrast imaging has been performed. In this contrast imaging, an ultrasonic contrast agent is injected from a vein and a blood flow signal is enhanced to evaluate blood flow dynamics in the heart, liver, kidney, and the like.

  In many contrast agents, microbubbles (microbubbles) function as a reflection source. Due to the sensitive nature of the bubbles, even if the ultrasonic irradiation sound pressure is at a normal diagnostic level, the bubbles are broken by the mechanical action, and the signal intensity from the scan section is reduced.

  Therefore, in order to observe the dynamic state of reflux in real time, it is necessary to reduce the collapse of bubbles due to scanning, such as by reducing the irradiation sound pressure. In addition, imaging by low sound pressure ultrasonic transmission reduces the signal / noise ratio (hereinafter referred to as “S / N ratio”), and various signal processing methods have been devised to compensate for this. ing.

  Furthermore, taking advantage of the feature that bubbles collapse, the following methods have been devised. That is, (a) observe the dynamics of bubbles filling the scan surface under low sound pressure irradiation, (b) switch the irradiation sound pressure to high sound pressure, and remove bubbles in the scan section (strictly in the irradiation volume). (C) This is a method of observing the state of bubbles that flow into the scan section by switching the irradiation sound pressure to a low sound pressure again. This kind of method is called replenishment method.

  Further, a technique has been devised in which a plurality of frame images are used to execute a maximum value holding calculation relating to luminance (hereinafter referred to as “brightness value holding calculation”) to effectively display microvessels (for example, (See Patent Document 1). If this luminance value holding calculation is performed, signals from bubbles present in the respective frame images are linked together, and a continuous blood vessel structure can be displayed.

  However, due to the nature of the luminance value holding calculation, if the execution time is long, there is a problem that the average luminance of the entire image increases too much due to the influence of the eco-o signal from the tissue, making it difficult to see the biological image. Furthermore, since the system noise that is not conspicuous in each frame image is held as a luminance value, there is a problem that the average luminance of the entire image increases and it becomes difficult to see the fine blood vessels. Therefore, when performing the luminance value holding calculation, it is necessary to optimize the gain and correct the average luminance of the entire image.

As a technique for optimizing the gain, a technique for adjusting the gain based on system noise and a signal from a tissue (for example, refer to Patent Document 2), or two gains based on two different images at the time of contrast imaging. A technique for calculating (see, for example, Patent Document 3) is known.
JP 2004-321688 A US6398733 JP 2004-24876 A

  However, the techniques described in Patent Documents 1 and 2 are effective for optimizing the luminance of a normal scan image, but cannot correct the average luminance of the entire image generated by the luminance value holding calculation.

  The present invention has been made in view of the above circumstances, and its purpose is to maintain a high-quality luminance value by correcting an increase in the average luminance of the entire image caused by a maximum-value-holding calculation related to luminance during contrast imaging. To provide an ultrasonic diagnostic apparatus and an ultrasonic diagnostic program capable of presenting an image.

  In order to solve the above problems and achieve the object, the ultrasonic diagnostic apparatus and the ultrasonic diagnostic program of the present invention are configured as follows.

(1) In an ultrasonic diagnostic apparatus that uses a plurality of B-mode images generated based on echo signals from a subject to perform a maximum value holding calculation related to luminance and generates a luminance value holding image, the maximum Gain correction amount generation means for generating a gain correction amount according to the execution time of the value holding calculation; and gain correction means for correcting the gain according to the gain correction amount generated by the gain correction amount generation means. .

(2) In the ultrasonic diagnostic apparatus described in (1), the gain correction amount generation unit generates a gain correction amount in accordance with a set time set in advance.

(3) In the ultrasonic diagnostic apparatus described in (1), the gain correction amount generation unit generates a gain correction amount according to an execution time when the maximum value holding operation is actually executed.

(4) In the ultrasonic diagnostic apparatus described in (1), the gain correction amount generation unit generates the gain correction amount so that a noise component is displayed with a predetermined luminance or less in the ultrasonic diagnostic image. To do.

(5) In an ultrasonic diagnostic apparatus that scans a subject to which a contrast medium has been administered with an ultrasonic wave and acquires a diagnostic image, the transmitter / receiver transmits an ultrasonic wave to the subject and receives an echo signal from the subject Means, image generating means for generating a plurality of B-mode images based on echo signals received by the transmitting / receiving means, and a maximum value holding operation relating to luminance using the plurality of B-mode images generated by the image generating means The image processing means for generating the brightness value holding image, the gain correction amount generating means for generating the gain correction amount of the brightness value holding image according to the execution time of the maximum value holding calculation, and the gain correction amount A gain correction unit that corrects the gain of the luminance value holding image according to the gain correction amount generated by the generation unit and generates a corrected luminance value holding image; and the gain correction unit And it includes an image display means for displaying the corrected luminance value holding image as the diagnostic image.

(6) In an ultrasonic diagnostic apparatus that scans a subject to which a contrast medium has been administered with an ultrasonic wave and obtains a diagnostic image, transmits / receives an ultrasonic wave to the subject and receives an echo signal from the subject Means, image generating means for generating a plurality of B-mode images based on echo signals received by the transmitting / receiving means, and gain correction for generating a gain correction amount of the B-mode image in accordance with a preset set time An amount generation unit, a gain correction unit that corrects the gain of the B-mode image according to the gain correction amount generated by the gain correction amount generation unit, and generates a plurality of corrected B-mode images; and the gain correction unit An image processing means for generating a corrected brightness value holding image by executing a maximum brightness holding operation using a plurality of generated corrected B-mode images, and the image processing means The corrected luminance value holding image which has been provided with an image display means for displaying as the diagnostic image.

(7) In the ultrasonic diagnostic apparatus described in (5) or (6), the gain correction amount generation unit is configured to display a noise component at a predetermined luminance or less in the corrected luminance value holding image. A gain correction amount is generated.

(8) In the ultrasonic diagnostic apparatus described in (6), the image processing unit stops the maximum value holding calculation when the execution time of the maximum value holding calculation reaches the set time. Reset the previous maximum value hold operation.

(9) In an ultrasound diagnostic program, a subject to which a contrast medium is administered is scanned with ultrasound, a computer is acquired to obtain a diagnostic image, and ultrasound is transmitted to the subject. Means for receiving an echo signal, means for generating a plurality of B-mode images based on the echo signals, and performing a maximum value holding operation on luminance using the plurality of B-mode images to generate a luminance value holding image Means for generating a gain correction amount of the luminance value holding image according to the execution time of the maximum value holding calculation; correcting the gain of the luminance value holding image according to the gain correction amount; And a means for displaying the corrected luminance value holding image as the diagnostic image.

(10) In the ultrasound diagnostic program, a subject to which a contrast medium is administered is scanned with ultrasound, a computer is acquired to obtain a diagnostic image, and ultrasound is transmitted to the subject. Means for receiving an echo signal; means for generating a plurality of B-mode images based on the echo signal; means for generating a gain correction amount of the B-mode image in accordance with a preset set time; and the gain correction amount And a means for generating a plurality of corrected B-mode images, performing a maximum value holding operation on luminance using the plurality of corrected B-mode images, and correcting the luminance value holding image. And a means for displaying the corrected luminance value holding image as the diagnostic image.

  According to the present invention, it is possible to present a high-quality luminance value holding image in which the average luminance of the entire image is optimized.

Hereinafter, first to fourth embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a configuration diagram of an ultrasonic diagnostic apparatus according to the first embodiment of the present invention. The ultrasonic diagnostic apparatus 10 includes an ultrasonic probe 12, an input device 13, a monitor (image display means) 14, a transmission / reception unit (transmission / reception means) 21, a B-mode processing unit 22, a Doppler processing unit 23, an image generation circuit (image generation). Means), an image memory 26, a control processor 27, a software storage unit 28, an internal storage device 29, and an interface unit 30.

  The ultrasonic probe 12 generates an ultrasonic wave by the driving voltage from the transmission / reception unit 21 and receives a reflected echo from the subject P.

  The input device 13 is connected to the device main body 11, and includes various switches, buttons, trackballs for taking various instructions, conditions, region of interest (ROI) setting instructions, and various image quality condition setting instructions from the operator into the device main body 11. Has a mouse, keyboard, etc.

  The monitor 14 displays in-vivo ecological information and blood flow information as an image based on the video signal from the image generation circuit 25.

  The transmission / reception unit 21 includes a trigger generation circuit, a delay circuit, a pulsar circuit, and the like (not shown). The pulser circuit repeatedly generates rate pulses for forming transmission ultrasonic waves at a predetermined rate frequency fr (Hz). The delay circuit converges the ultrasonic wave into a beam shape for each channel and gives each rate pulse a delay time necessary to determine the transmission directivity. The trigger generation circuit applies a drive voltage to the ultrasonic probe 12 at a timing based on this rate pulse.

  Further, the transmission / reception unit 21 includes a preamplifier circuit, an A / D converter, an adder, and the like which are not shown. The preamplifier circuit amplifies the echo signal captured from the ultrasonic probe 12 for each channel. The A / D converter converts the amplified echo signal into a digital signal. The adder performs an addition process by giving a delay time for determining the reception directivity to the echo signal.

  The B-mode processing unit 22 receives the echo signal from the transmission / reception unit 21, performs logarithmic amplification, envelope detection processing, and the like, and generates data in which the signal intensity is expressed by brightness. This data is transmitted to the image generation circuit 25 and displayed on the monitor 14 as a B-mode image in which the intensity of the reflected echo is expressed by luminance.

  The Doppler processing unit 23 performs frequency analysis on velocity information from the echo signal received from the transmission / reception unit 21, extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect, and obtains blood flow information such as average velocity, dispersion, and power. Ask for multiple points. The obtained blood flow signal is sent to the image generation circuit 25 and displayed in color on the monitor 14 as an average velocity image, a dispersion image, a power image, and an image obtained by combining these.

  The image generation circuit 25 converts the scanning line signal sequence of the ultrasonic scan into a scanning line signal sequence of a general video format represented by a television, and generates an ultrasonic diagnostic image as a display image.

  FIG. 2 is a configuration diagram of the image generation circuit 25 according to the embodiment. The image generation circuit 25 includes a signal processing circuit 25a, a scan converter 25b, and an image processing circuit (image processing means, gain correction means) 25c.

  The signal processing circuit 25a performs filtering so as to determine an image at the level of the scanning line signal string of the ultrasonic scan. The output of the signal processing circuit 25a is sent to the scan converter 25b and simultaneously stored in the image memory 26.

  The scan converter 25b converts the scanning line signal sequence of ultrasonic scanning into a scanning line signal sequence of a general video format represented by a television. The output of the scan converter 25b is sent to the image processing circuit 25c as image data.

  The image processing circuit 25c performs brightness and contrast adjustment, image processing such as a spatial filter, synthesis with character information and scales of various setting parameters, and the like on the image data, and outputs the video signal to the monitor 14 as a video signal. Output. Further, the image processing circuit 25c reads image data stored in the image memory 26 and executes a maximum value holding operation regarding luminance. Further, the image processing circuit 25c corrects the gain of the image data using the gain correction value (gain correction amount) specified by the gain correction table. However, in the first embodiment and the second embodiment described later, the B-mode processing unit 22 may perform gain correction on the image data.

  The image memory 26 includes a storage memory that stores image data received from the signal processing circuit 25a. The image data can be called by an operator after diagnosis, for example, and can be reproduced as a still image or a moving image using a plurality of images.

  The internal storage device 29 includes a control program for executing a maximum value luminance holding process, a gain correction process, an image generation, and a display process, which will be described later, a gain correction table, diagnostic information, a diagnostic protocol, transmission / reception conditions, and other data groups. It is stored.

  The control processor 27 has a function as an information processing apparatus and is a control means for controlling the operation of the ultrasonic diagnostic apparatus main body. The control processor 27 reads out, from the internal storage device 29, a control program for executing generation / display of a diagnostic image, which will be described later, and develops it on the software storage unit 28, and executes calculation / control and the like regarding various processes.

  The interface unit 30 is an interface related to the input device 13, the network, and a new external storage device (not shown). Data such as ultrasonic images and analysis results obtained by the apparatus can be transferred to another apparatus via the network by the interface unit 39.

(Scan sequence)
Next, a basic scan sequence executed by the ultrasound diagnostic apparatus 10 will be described with reference to FIG. This scan sequence alternately executes high sound pressure transmission for collapsing contrast agent bubbles and low sound pressure transmission for acquiring diagnostic images without disrupting contrast agent bubbles as much as possible in contrast contrast using a contrast agent. To do. The contrast agent is preferably a so-called “next-generation contrast agent” capable of emitting a harmonic signal without being destroyed even when low sound pressure ultrasonic waves are transmitted and capable of imaging for a long time.

  FIG. 3 is a diagram for explaining a scan sequence according to the embodiment, in which the horizontal axis represents time, and the vertical axis represents the degree of mechanical action on contrast medium bubbles by transmission. Each line represents an ultrasonic scan for one frame, and the length of each line represents the mechanical action strength of the transmission sound pressure of each frame.

  That is, each line represents an ultrasonic scan for one frame based on a transmission condition set as a combination of a transmission frequency that is lower, a transmission drive voltage is greater, or a combination thereof, as the length in the vertical direction is longer. Therefore, a long line corresponds to a scan by high sound pressure irradiation, and a short line corresponds to a scan by low sound pressure irradiation.

(Generation / display of diagnostic images)
Next, a diagnostic image generation / display method executed by the ultrasonic diagnostic apparatus 10 will be described with reference to FIGS. 4 is a schematic diagram of the input device 13 according to the embodiment. FIG. 5 is a schematic diagram of a frame image according to the embodiment. FIG. 6 is a schematic diagram of a luminance value holding image before gain correction according to the embodiment. FIG. 7 is a schematic diagram of a luminance value holding image after gain correction according to the embodiment. In addition, the part shown with the dot and diagonal line in FIGS.

  In accordance with instructions from the switches 13a and 13b of the input device 13 shown in FIG. 4, an execution time TH (hereinafter referred to as “high sound pressure period”) of ultrasonic transmission at high sound pressure (hereinafter referred to as “high sound pressure transmission”), and An execution time TL (hereinafter referred to as “low sound pressure period”) of ultrasonic transmission at low sound pressure (hereinafter referred to as “low sound pressure transmission”) is set.

  And a scan sequence is started by operation of the start switch 13c of the input device 13 shown in FIG. In this scan sequence, the contrast agent bubbles in the blood vessel are destroyed by the mechanical action of the high sound pressure transmission executed first, and the contrast agent bubbles circulating in the blood vessel are imaged by the low sound pressure transmission executed thereafter. .

  In addition, when low sound pressure transmission is started, a maximum value holding calculation relating to luminance (hereinafter referred to as “brightness value holding calculation”) is started, and a state in which contrast medium bubbles flow into a fine blood vessel branch is a luminance value holding image. Is displayed on the monitor.

  Note that the luminance value holding calculation is to select a maximum luminance value Pmax (x, y) from spatially corresponding pixels in a plurality of frame images (FIG. 5), and to obtain one image, that is, a luminance value holding image. (FIG. 6) is generated.

  By the way, as described in the section of the prior art, when the luminance value holding calculation is executed using the frame image as shown in FIG. 5 generated by low sound pressure transmission as it is, the luminance value holding image is displayed as shown in FIG. There is a problem that the average brightness is too high.

  Therefore, in the present embodiment, when generating the luminance value holding image, each frame image is gain-corrected to reduce the average luminance of each frame image in advance. As a result, the average luminance of the luminance value holding image becomes a luminance suitable for diagnosis as shown in FIG.

  In gain correction, a gain correction table stored in the internal storage device 29 is used. This gain correction table is a curve that associates the execution time of the luminance value holding calculation with the gain correction value on a one-to-one basis. By setting the execution time of the luminance value holding calculation, the corresponding gain correction value is determined. It is supposed to be.

  That is, when the execution time of the luminance value holding calculation, that is, the low sound pressure period TL is set by operating the switch 13b, a gain correction value corresponding to the low sound pressure period TL is specified from the gain correction table, and the gain correction value is Thus, the gain correction of each frame image is executed.

(Gain correction function)
Next, gain correction processing executed by the ultrasound diagnostic apparatus 10 will be described with reference to FIG. FIG. 8 is a flowchart showing the flow of gain correction processing in the image generation / display method according to the embodiment.

  First, the high sound pressure period TH is set to 0.5 seconds and the low sound pressure period TL is set to 2 seconds by the operation of the switches 13a and 13b by the operator (step S0). After the setting, a gain correction value Gm corresponding to the low sound pressure period TL is designated from the gain correction table stored in the internal storage device 29 (step S1). After the gain correction value is designated, the above-described scan sequence is started by an instruction from the start switch 13c by the operator (step S2).

  In this scan sequence, first, the scan condition is switched to high sound pressure transmission (step S3). When high sound pressure transmission is executed for 0.5 seconds (step S4), the scanning condition is switched to low sound pressure transmission (step S5). At the same time, information related to the previous luminance value holding calculation is reset (step S5). S6).

  Then, each frame image is gain-corrected according to the gain correction value Gm (step S7), and then low sound pressure transmission and a new luminance value holding calculation are started (step S8). When the low sound pressure transmission is executed for 2 seconds (step S9), the luminance value holding calculation is stopped (step S10), and at the same time, the scan sequence is automatically ended (step S11). That is, the luminance value holding calculation is performed until the low sound pressure transmission is completed.

  In addition, in the process of steps S6 to S10, the luminance value holding image obtained by low sound pressure transmission and subjected to the luminance value holding calculation is displayed on the monitor 14 in real time as a recirculation image.

(Transition of display image)
When high sound pressure transmission is started, the contrast agent bubbles in the blood vessel are destroyed by the mechanical action. As a result, the tissue image disappears from the monitor 14, and the entire image becomes dark. When low sound pressure transmission is started, the contrast medium bubbles recirculate in the blood vessel, and the state is displayed on the monitor 14 as a luminance value holding image.

  Immediately after the start of low sound pressure transmission, the average luminance of the luminance value holding image is considerably lower than the luminance optimum for diagnosis. This is because gain correction is performed in advance so that the average luminance of the luminance value holding image does not increase excessively.

  However, the average luminance of the luminance value holding image gradually increases as the number of executions of the luminance value holding calculation increases, and becomes the optimum luminance for diagnosis when two seconds have elapsed after the low sound pressure transmission is started.

(Operation by this embodiment)
According to this embodiment, each frame image generated by low sound pressure transmission is gain-corrected in advance so that the average luminance of the entire image in the luminance value holding image becomes the optimum luminance for diagnosis. Therefore, even if the luminance value holding calculation is performed using these frame images, the average luminance of the entire luminance value holding image does not increase excessively, and a good diagnostic image in which fine blood vessels are clearly displayed is generated. .

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 9 is a flowchart showing the flow of gain correction processing in the image generation / display method according to the second embodiment of the present invention.

  In the present embodiment, first, the high sound pressure period TH is set to 0.5 seconds and the low sound pressure period TL is set to 2 seconds according to an instruction from the switches 13a and 13b by the operator (step S20).

  After the setting, the gain correction value Gm corresponding to the low sound pressure period TL is designated from the gain correction table stored in the internal storage device 29 (step S21). After the gain correction value is designated, the main scan sequence is started by the operation of the start switch 13c by the operator (step S22).

  In this scan sequence, first, the scan condition is switched to high sound pressure transmission (step S23). When the high sound pressure transmission is executed for 0.5 seconds (step S24), the scanning condition is switched to low sound pressure transmission (step S25), and at the same time, information relating to the luminance value holding calculation is reset (step S26).

  Then, each frame image is gain-corrected according to the gain correction value Gm (step S27), and then low sound pressure transmission and a new luminance value holding calculation are started (step S28). Then, the luminance value holding calculation is stopped by the operation of the stop switch 13d by the operator (step S29), and at the same time, the scan sequence is ended (step S30). That is, the luminance value holding calculation is performed until the low sound pressure transmission is completed.

  In addition, in the process of steps S26 to S29, the luminance value holding image obtained by the low sound pressure transmission and subjected to the luminance value holding calculation is displayed on the monitor 14 in real time as a recirculation image.

  That is, in the gain correction method according to the present embodiment, the low sound pressure period TL is used only for designating the gain correction value Gm, and the low sound pressure transmission ends when the operator operates the stop switch 13d.

(Operation by this embodiment)
According to the present embodiment, the low sound pressure transmission ends when the operator presses the stop switch 13d. That is, when the low sound pressure period TL ends, the ultrasonic diagnostic apparatus 10 does not automatically stop low sound pressure transmission.

  Therefore, when a sufficiently low blood pressure structure TL does not appear in the luminance value holding image when the originally scheduled low sound pressure period TL ends, the stop of the low sound pressure transmission can be delayed by the operator's judgment. On the other hand, if a sufficient blood vessel structure appears in the luminance value holding image before the originally scheduled low sound pressure period TL ends, the low sound pressure transmission can be stopped earlier by the operator's judgment. Therefore, it is possible to obtain a brightness value holding image that is optimal for the operator.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 10 is a flowchart showing the flow of gain correction processing in the image generation / display method according to the third embodiment of the present invention.

  In the present embodiment, first, the high sound pressure period TH is set to 0.5 seconds according to an instruction from the switch 13a by the operator (step S40). After the setting, the main scan sequence is started by the operation of the start switch 13c by the operator (step S41).

  In this scan sequence, the scan condition is first switched to high sound pressure transmission (step S42). When the high sound pressure transmission is executed for 0.5 seconds (step S43), the scanning condition is switched to the low sound pressure transmission (step S44), and at the same time, information relating to the luminance value holding calculation is reset (step S45).

  Then, low sound pressure transmission and a new luminance value holding calculation are started (step S46), and the luminance value holding calculation is stopped by the operation of the stop switch 13d by the operator (step S47), and at the same time, a scan sequence (low sound pressure transmission). ) Ends (step S48). That is, the luminance value holding calculation is stopped simultaneously with the end of the low sound pressure transmission.

  Then, simultaneously with the end of the scan sequence, the low sound pressure period TL during which the low sound pressure transmission was executed is calculated, and the gain correction value corresponding to this low sound pressure period TL is calculated from the gain correction table stored in the internal storage device 29. Gm is designated (step S49). Then, the luminance value holding image is gain-corrected according to the gain correction value Gm (step S50), and the gain-corrected luminance value holding image is displayed on the monitor 14 as a still image.

  Therefore, in the present embodiment, the average luminance of the luminance value holding image becomes the maximum luminance when 2 seconds have elapsed since the start of the low-temperature pressure transmission, and becomes the optimal luminance for diagnosis by subsequent gain correction.

  That is, the low sound pressure period TL in the gain correction method according to the present embodiment is not set before the start of scanning, but is determined by the experience and feeling of the operator after the start of scanning.

(Operation by this embodiment)
According to the present embodiment, when the operator presses the stop switch 13d, the low sound pressure transmission ends, and the low sound pressure period TL that is the execution time of the low sound pressure transmission up to that point is calculated. . That is, it is not necessary to input the low sound pressure period TL in advance. Therefore, the work burden on the worker can be reduced.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a diagram for explaining a scan sequence according to the fourth embodiment of the present invention, and FIG. 12 is a diagram illustrating luminance value holding when a luminance value holding calculation is executed in a state where only white noise according to the embodiment is displayed. FIG. 13 is a graph showing a gain correction table according to the embodiment.

  In the present embodiment, when the echo signal from the tissue does not significantly affect the luminance value holding image, that is, the luminance value holding image in which the fine blood vessels are clearly displayed is obtained only by removing the influence of white noise from the luminance value holding image. This is an effective method when it can be obtained.

(Scan sequence)
As shown in FIG. 11, the scan sequence according to the present embodiment incorporates a non-transmission period TN immediately before low sound pressure transmission in the scan sequence. In the non-transmission period TN, only reception by the ultrasonic probe 12 is performed, and thereby white noise or the like inherent to the acoustic diagnostic apparatus 10 is measured.

  Since white noise is randomly generated on each frame image, when the luminance value holding calculation is performed, the average luminance of the luminance value holding image gradually increases with time as shown in FIG. Therefore, as the gain correction table, as shown in FIG. 13, a curve in which the gain correction value increases negatively with the passage of time is used to cancel the increase in the average luminance of the luminance value holding image caused by white noise. .

  By the way, the ratio of the change in the average luminance of the luminance value holding image caused by white noise differs depending on the noise level at the start of the luminance value holding calculation. Therefore, a plurality of gain correction tables indicating the relationship between the level of white noise at the start of the luminance value holding calculation and the average luminance of the luminance value holding image after a predetermined time from the start of the luminance value holding calculation are stored in advance in the internal storage device 29. And an optimum gain correction table corresponding to the level of white noise at the start of the luminance value holding calculation is referred to.

(Gain correction function)
Next, gain correction processing executed by the ultrasound diagnostic apparatus 10 will be described with reference to FIG. FIG. 14 is a flowchart showing the flow of gain correction processing in the image generation / display method according to the embodiment.

  First, according to an instruction from the switches 13a and 13b by the operator, the high sound pressure period TH is set to 0.5 seconds and the low sound pressure period TL is set to 2 seconds (step S60). After the setting, the main scan sequence is started by the operation of the start switch 13c by the operator (step S61).

  In this scan sequence, first, the scan condition is switched to high sound pressure transmission (step S62). When high sound pressure transmission is executed for 0.5 seconds (step S63), ultrasonic transmission is stopped for the non-transmission period TN, and only reception is performed in the non-transmission state (step S64).

  After the reception, a noise level is calculated based on the obtained echo signal, and a gain correction table optimal for the noise level is selected from a plurality of gain correction tables stored in the internal storage device 29. Then, a gain correction value Gm corresponding to the low sound pressure period TL is designated from the selected gain correction table (step S65).

  After specifying the gain correction value, the scanning condition is switched to low sound pressure transmission (step S66), and at the same time, information related to the previous luminance value holding calculation is reset (step S67). Then, each frame image is gain-corrected according to the gain correction value Gm (step S68), and then low sound pressure transmission and a new luminance value holding calculation are started (step S69).

  When the low sound pressure transmission and the luminance value holding calculation are executed for 2 seconds (step S70), the luminance value holding calculation is stopped (step S71), and at the same time, the scan sequence is automatically ended (step S72).

  That is, in this embodiment, a noise level unique to a device such as white noise is measured from an echo signal in a non-transmission state in which ultrasonic transmission is stopped, and a gain correction table corresponding to the level of white noise is selected. Then, a gain correction value Gm corresponding to the low sound pressure period TL is designated from the selected gain correction table.

(Operation by this embodiment)
According to the present embodiment, before performing low sound pressure transmission, only reception without transmission is performed to measure the level of white noise unique to the apparatus, and a gain correction table corresponding to the level of white noise is referred to. I have to.

  Therefore, even if the level of white noise changes depending on the transmission conditions, the change in the average luminance of the luminance value holding image caused by the white noise is accurately predicted, so that the fine blood vessels are clear without being affected by the transmission conditions. A displayed diagnostic image can be obtained.

  In this embodiment, white noise level measurement is incorporated in the flow of gain correction processing according to the first embodiment, but the present invention is not limited to this, and is incorporated in, for example, the second to third embodiments. But it ’s okay.

  The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

1 is a configuration diagram of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention. FIG. 3 is a configuration diagram of an image generation circuit according to the embodiment. The figure for demonstrating the scan sequence which concerns on the same embodiment. Schematic of the input device according to the embodiment. Schematic of the frame image which concerns on the same embodiment. Schematic of the brightness value holding image before gain correction according to the embodiment. FIG. 3 is a schematic diagram of a luminance value holding image after gain correction according to the embodiment. 6 is a flowchart showing a flow of gain correction processing in the image generation / display method according to the embodiment; The flowchart which shows the flow of the gain correction process in the image generation and display method which concerns on 2nd Embodiment of this invention. 10 is a flowchart showing a flow of gain correction processing in an image generation / display method according to a third embodiment of the present invention. The figure for demonstrating the scan sequence which concerns on 4th Embodiment of this invention. The graph which shows the time change of the average brightness | luminance of a brightness | luminance value holding | maintenance image at the time of performing a brightness | luminance value holding | maintenance calculation in the state which displayed only the white noise which concerns on the embodiment. The graph which shows the gain correction table which concerns on the same embodiment. 6 is a flowchart showing a flow of gain correction processing in the image generation / display method according to the embodiment;

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Ultrasound diagnostic apparatus, 14 ... Monitor (image display means), 21 ... Transmission / reception unit (transmission / reception means), 25 ... Image generation circuit (image generation means), 25c ... Image processing circuit (image processing means, gain correction means) 29 ... Internal storage device (gain correction amount generating means), Gm ... Gain correction amount, P ... Subject.

Claims (10)

In an ultrasonic diagnostic apparatus that uses a plurality of B-mode images generated based on echo signals from a subject, performs a maximum value holding operation on luminance, and generates a luminance value holding image,
A gain correction amount generating means for generating a gain correction amount according to an execution time of the maximum value holding calculation;
Gain correction means for correcting the gain according to the gain correction amount generated by the gain correction amount generation means;
An ultrasonic diagnostic apparatus comprising:   The ultrasonic diagnostic apparatus according to claim 1, wherein the gain correction amount generation unit generates a gain correction amount according to a preset time set in advance.   The ultrasonic diagnostic apparatus according to claim 1, wherein the gain correction amount generation unit generates a gain correction amount according to an execution time when the maximum value holding calculation is actually executed.   The ultrasonic diagnostic apparatus according to claim 1, wherein the gain correction amount generation unit generates the gain correction amount so that a noise component is displayed at a predetermined luminance or less in the ultrasonic diagnostic image. In an ultrasonic diagnostic apparatus that scans a subject to which a contrast medium is administered with an ultrasonic wave and acquires a diagnostic image,
Transmitting / receiving means for transmitting an ultrasonic wave to the subject and receiving an echo signal from the subject;
Image generating means for generating a plurality of B-mode images based on echo signals received by the transmitting / receiving means;
Image processing means for generating a luminance value holding image by executing a maximum value holding calculation relating to luminance using a plurality of B-mode images generated by the image generation means;
A gain correction amount generating means for generating a gain correction amount of the luminance value holding image according to an execution time of the maximum value holding calculation;
Gain correcting means for correcting the gain of the luminance value holding image according to the gain correction amount generated by the gain correction amount generating means, and generating a corrected luminance value holding image;
Image display means for displaying the corrected luminance value holding image generated by the gain correction means as the diagnostic image;
An ultrasonic diagnostic apparatus comprising: In an ultrasonic diagnostic apparatus that scans a subject to which a contrast medium is administered with an ultrasonic wave and acquires a diagnostic image,
Transmitting / receiving means for transmitting an ultrasonic wave to the subject and receiving an echo signal from the subject;
Image generating means for generating a plurality of B-mode images based on echo signals received by the transmitting / receiving means;
A gain correction amount generating means for generating a gain correction amount of the B-mode image according to a set time set in advance;
Gain correcting means for correcting the gain of the B-mode image according to the gain correction amount generated by the gain correction amount generating means, and generating a plurality of corrected B-mode images;
Image processing means for executing a maximum value holding calculation relating to luminance using a plurality of corrected B-mode images generated by the gain correcting means, and generating a corrected luminance value holding image;
Image display means for displaying the corrected luminance value holding image generated by the image processing means as the diagnostic image;
An ultrasonic diagnostic apparatus comprising:   The ultrasound according to claim 5 or 6, wherein the gain correction amount generation unit generates the gain correction amount so that a noise component is displayed at a predetermined luminance or less in the corrected luminance value holding image. Diagnostic device.   The image processing means stops the maximum value holding calculation and resets the previous maximum value holding calculation when the execution time of the maximum value holding calculation reaches the set time. Item 6. The ultrasonic diagnostic apparatus according to Item 6. A computer to scan the subject to which the contrast agent is administered with ultrasound and acquire a diagnostic image,
Means for transmitting an ultrasonic wave to the subject and receiving an echo signal from the subject;
Means for generating a plurality of B-mode images based on the echo signals;
Means for performing a maximum value holding operation on luminance using the plurality of B-mode images and generating a luminance value holding image;
Means for generating a gain correction amount of the luminance value holding image according to an execution time of the maximum value holding calculation;
Means for correcting the gain of the luminance value holding image in accordance with the gain correction amount and generating a corrected luminance value holding image; and means for displaying the corrected luminance value holding image as the diagnostic image;
Ultrasound diagnostic program to function as A computer to scan the subject to which the contrast agent is administered with ultrasound and acquire a diagnostic image,
Means for transmitting an ultrasonic wave to the subject and receiving an echo signal from the subject;
Means for generating a plurality of B-mode images based on the echo signals;
Means for generating a gain correction amount of the B-mode image in accordance with a preset setting time;
Means for correcting the gain of the B-mode image in accordance with the gain correction amount and generating a plurality of corrected B-mode images;
Means for performing a maximum value holding operation on luminance using the plurality of corrected B-mode images and generating a corrected luminance value holding image; and means for displaying the corrected luminance value holding image as the diagnostic image;
Ultrasound diagnostic program to function as

Images