JP2012157387A - Ultrasonic diagnostic apparatus and image generation control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate an ultrasonic image wherein azimuth resolution in an interested area always becomes high.SOLUTION: This ultrasonic diagnostic apparatus includes: an image generation part 15a, a detection part 15b, a determination part 15c, and a control part 18. The image generation part 15a generates an ultrasonic image of each of a plurality of setting sound velocities from each of reflected wave data of an ultrasonic wave added by use of each reception delay time calculated from the plurality of setting sound velocities. The detection part 15b divides each ultrasonic image of each of the plurality of setting sound velocities into a plurality of sections, and detects the setting sound velocity wherein a luminance value or a contrast value becomes optimal in the same section, in each of the plurality of sections. The determination part 15c determines the setting sound velocity becoming optimal so as to draw the interested area based on the setting sound velocity of each of the plurality of sections detected to be optimum. The control part 18 performs control such that the ultrasonic image based on the setting sound velocity determined by the determination part 15c is generated in the image generation part 15a.

Description

  Embodiments described herein relate generally to an ultrasonic diagnostic apparatus and an image generation control program.

  Conventionally, in imaging using an ultrasonic diagnostic apparatus, a dynamic focusing method is used to increase the azimuth resolution of an ultrasonic image. The time from when the ultrasonic wave is transmitted until the reflected wave is received is proportional to the depth of the reflected echo source. Therefore, in the dynamic focusing method, the reception delay time used for adding the received signals (phased addition) is switched according to the elapsed time from the ultrasonic transmission, so that reception from each focusing point having a different depth direction is performed. Focus the signal. Specifically, when performing the dynamic focusing method, the ultrasonic diagnostic apparatus calculates a reception delay time at each transducer for each different focusing point, and uses the calculated reception delay time for each focusing point to obtain a depth. An ultrasonic image is generated by adding the received signals from the focusing points having different directions.

  Here, when the reception delay time at each focusing point is calculated by the dynamic focusing method, a value set as the sound speed in the living body (hereinafter referred to as a set sound speed) is used. However, if there is a difference between the set sound speed and the actual biological sound speed, the focal point of the received signal is shifted, and even if the dynamic focusing method is used, the azimuth resolution of the ultrasonic image may be lowered.

  For this reason, in recent years, a technique for obtaining an optimum set sound speed is known. In such a technique, an ultrasonic image at each set sound speed is acquired while changing the set sound speed used for calculating the reception delay time, and the optimum set sound speed (optimum) is evaluated by evaluating the contrast and brightness of each acquired ultrasonic image. (Sonic velocity). Specifically, the ultrasound diagnostic apparatus divides an ultrasound image at each set sound speed into a plurality of sections, and obtains a set sound speed (optimum sound speed) at which the contrast value is optimal for each section, for example. Then, the ultrasonic diagnostic apparatus feeds back the optimum sound speed for each section or the optimum sound speed for the entire image or for each depth direction calculated from the optimum sound speed for each section to the reception delay circuit.

  However, the set sound speed required by the above technique may not always be an optimum value for observing the region of interest.

JP 2008-264531 A

  The problem to be solved by the present invention is to provide an ultrasonic diagnostic apparatus and an image generation control program capable of generating an ultrasonic image in which the azimuth resolution of a region of interest is always high.

  The ultrasonic diagnostic apparatus according to the embodiment includes an image generation unit, a detection unit, a determination unit, and a control unit. The image generation unit is configured to detect the supersonic wave for each of the plurality of set sound speeds from each of the reflected wave data of the ultrasonic waves added using the reception delay times calculated from the plurality of set sound speeds set as the sound speeds in the imaging target region. A sound image is generated. The detection unit divides each of the ultrasonic images for each of the plurality of set sound speeds generated by the image generation unit into a plurality of sections, and sets the sound speed at which the luminance value or the contrast value is optimal in the same section, Detection is performed for each of the plurality of sections. The determination unit determines a set sound speed that is optimal for rendering the region of interest based on the set sound speed for each of the plurality of sections detected as optimal by the detection unit. The control unit performs control so that an ultrasonic image based on the set sound speed determined by the determination unit is generated by the image generation unit.

FIG. 1 is a diagram for explaining the configuration of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 2 is a diagram for explaining an example of an ultrasonic image generated by the image generation unit according to the first embodiment. FIG. 3 is a diagram for explaining an example of processing by the detection unit according to the first embodiment. FIG. 4 is a diagram for explaining a conventional technique using the detection result of the detection unit. FIG. 5 is a diagram (1) for explaining the determination unit according to the first embodiment. FIG. 6 is a diagram (2) for explaining the determination unit according to the first embodiment. FIG. 7 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 8 is a diagram for explaining an example of setting information used by the determination unit according to the second embodiment. FIG. 9 is a diagram for explaining a determination unit according to the second embodiment. FIG. 10 is a diagram for explaining another example of the setting information used by the determination unit according to the second embodiment. FIG. 11 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the second embodiment. FIG. 12 is a diagram (1) for explaining the determination unit according to the third embodiment. FIG. 13 is a diagram (2) for explaining the determination unit according to the third embodiment. FIG. 14 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the third embodiment. FIG. 15 is a diagram for explaining a determination unit according to the fourth embodiment. FIG. 16 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the fourth embodiment.

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

(First embodiment)
First, the configuration of the ultrasonic diagnostic apparatus according to the first embodiment will be described. FIG. 1 is a diagram for explaining the configuration of the ultrasonic diagnostic apparatus according to the first embodiment. As shown in FIG. 1, the ultrasonic diagnostic apparatus according to the first embodiment includes an ultrasonic probe 1, a monitor 2, an input device 3, and an apparatus main body 10.

  The ultrasonic probe 1 is detachably connected to the apparatus main body 10. The ultrasonic probe 1 has a plurality of piezoelectric vibrators, and the plurality of piezoelectric vibrators generate ultrasonic waves based on a drive signal supplied from a transmission unit 11 included in the apparatus main body 10 to be described later. The ultrasonic probe 1 receives a reflected wave from the subject P and converts it into an electrical signal. The ultrasonic probe 1 includes a matching layer provided in the piezoelectric vibrator, a backing material that prevents propagation of ultrasonic waves from the piezoelectric vibrator to the rear, and the like.

  When ultrasonic waves are transmitted from the ultrasonic probe 1 to the subject P, the transmitted ultrasonic waves are reflected one after another at the discontinuous surface of the acoustic impedance in the body tissue of the subject P, and the ultrasonic probe is used as a reflected wave signal. 1 is received by a plurality of piezoelectric vibrators. The amplitude of the received reflected wave signal depends on the difference in acoustic impedance at the discontinuous surface where the ultrasonic wave is reflected. Note that the reflected wave signal when the transmitted ultrasonic pulse is reflected on the moving blood flow or the surface of the heart wall depends on the velocity component of the moving body in the ultrasonic transmission direction due to the Doppler effect. And undergoes a frequency shift.

  Here, the present embodiment is applicable regardless of whether the ultrasonic scanning mode by the ultrasonic probe 1 is linear scanning or sector scanning.

  The input device 3 includes a mouse, a keyboard, a button, a panel switch, a touch command screen, a foot switch, a trackball, and the like, accepts various setting requests from an operator of the ultrasonic diagnostic apparatus, and accepts them to the apparatus body 10. Transfer various setting requests. The contents of the settings that the input device 3 according to the first embodiment receives from the operator will be described in detail later.

  The monitor 2 displays a GUI (Graphical User Interface) for an operator of the ultrasonic diagnostic apparatus to input various setting requests using the input device 3 or displays an ultrasonic image generated in the apparatus main body 10. Or

  The apparatus main body 10 is an apparatus that generates an ultrasonic image based on the reflected wave received by the ultrasonic probe 1. As shown in FIG. 1, the apparatus main body 10 includes a transmission unit 11, a reception unit 12, a B-mode processing unit 13, a Doppler processing unit 14, an image processing unit 15, an image memory 16, and an image composition unit 17. And a control unit 18 and an internal storage unit 19.

  The transmission unit 11 includes a trigger generation circuit, a transmission delay circuit, a pulsar circuit, and the like, and supplies a drive signal to the ultrasonic probe 1. The pulsar circuit repeatedly generates rate pulses for forming transmission ultrasonic waves at a predetermined rate frequency. Each transmission delay circuit generates a transmission delay time for each piezoelectric vibrator necessary for determining transmission directivity by focusing ultrasonic waves generated from the ultrasonic probe 1 into a beam shape. Give to rate pulse. The trigger generation circuit applies a drive signal (drive pulse) to the ultrasonic probe 1 at a timing based on the rate pulse. The transmission delay circuit arbitrarily adjusts the transmission direction from the piezoelectric vibrator surface by changing the transmission delay time given to each rate pulse.

  That is, the transmission delay circuit controls the position of the focal point (transmission focus) in the depth direction of ultrasonic transmission by giving a transmission delay time to each rate pulse generated by the pulser circuit. Note that the first embodiment is a case where the transmission unit 11 can perform multi-focusing in which an ultrasonic beam is transmitted a plurality of times while changing the depth of a transmission focus point on the same scan line. There may be. When multistage focusing is performed, the transmission delay circuit included in the transmission unit 11 calculates a transmission delay time corresponding to the depth of each transmission focus point, and supplies the transmission delay time to the pulsar circuit.

  Further, the transmission unit 11 has a function capable of instantaneously changing a transmission frequency, a transmission drive voltage, and the like in order to execute a predetermined scan sequence based on an instruction from the control unit 18 described later. In particular, the change of the transmission drive voltage is realized by a linear amplifier type transmission circuit capable of instantaneously switching the value or a mechanism for electrically switching a plurality of power supply units.

  The receiving unit 12 includes an amplifier circuit, an A / D converter, a reception delay circuit, an adder, and the like, and performs various processes on the reflected wave signal received by the ultrasonic probe 1 to generate reflected wave data. The amplifier circuit amplifies the reflected wave signal for each channel and performs gain correction processing. The A / D converter A / D converts the reflected wave signal whose gain is corrected. The reception delay circuit gives a reception delay time necessary for determining the reception directivity to the digital data. The adder performs the addition process of the reflected wave signal given the reception delay time by the reception delay circuit to generate the reflected wave data. By the addition processing of the adder, the reflection component from the direction corresponding to the reception directivity of the reflected wave signal is emphasized.

  Here, the reception delay circuit included in the reception unit 12 according to the first embodiment uses the sound velocity of the body tissue of the subject P, which is an imaging target of the ultrasonic image, when performing the dynamic focusing method. Based on a preset “set sound velocity”, a distribution of reception delay times given to each transducer is calculated for each of a plurality of focusing points. Then, the reception delay circuit gives the calculated “reception delay time distribution” to the adder. Based on the distribution of the reception delay time, the adder performs reception delay time control so that the focusing point continuously moves in the depth direction with time, thereby reflecting the reflected wave signal (digital data) from the focused area. ) Is added.

  Here, the set sound speed can be changed, for example, within a variable range that can be variably set in the ultrasonic diagnostic apparatus. The transmission delay circuit included in the transmission unit 11 can also calculate the transmission delay time based on the set sound speed used for calculating the reception delay time.

  As described above, the transmission unit 11 and the reception unit 12 control transmission directivity and reception directivity in transmission / reception of ultrasonic waves.

  The B-mode processing unit 13 receives the reflected wave data from the receiving unit 12, performs logarithmic amplification, envelope detection processing, and the like, and generates data (B-mode data) in which the signal intensity is expressed by brightness. .

  The Doppler processing unit 14 performs frequency analysis on velocity information from the reflected wave data received from the receiving unit 12, extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect, and mobile object information such as average velocity, dispersion, and power. Is generated for multiple points (Doppler data).

  The image processing unit 15 determines to perform processing using an image generation unit 15a that generates an ultrasonic image, a detection unit 15b that analyzes an ultrasonic image generated by the image generation unit 15a, and an analysis result of the detection unit 15b. Part 15c.

  The image generation unit 15a generates an ultrasonic image from the data generated by the B mode processing unit 13 and the Doppler processing unit 14. That is, the image generation unit 15a generates a B-mode image in which the intensity of the reflected wave is expressed by luminance from the B-mode data generated by the B-mode processing unit 13. In addition, the image generation unit 15a generates a color Doppler image as an average velocity image, a dispersed image, a power image, or a combination image thereof representing moving body information from the Doppler data generated by the Doppler processing unit 14.

  Here, the image generation unit 15a generally converts (scan converts) a scanning line signal sequence of ultrasonic scanning into a scanning line signal sequence of a video format typified by a television or the like, and serves as a display image. Generate an ultrasound image. Specifically, the image generation unit 15a generates an ultrasonic image as a display image by performing coordinate conversion in accordance with the ultrasonic scanning mode by the ultrasonic probe 1. In addition to the scan conversion, the image generation unit 15a performs various image processing, such as image processing (smoothing processing) for regenerating an average luminance image using a plurality of image frames after scan conversion, Image processing (edge enhancement processing) using a differential filter is performed in the image.

  Note that the ultrasonic image generated by the image generation unit 15a and the processing contents of the detection unit 15b and the determination unit 15c will be described in detail later.

  The image composition unit 17 generates a composite image in which character information, scales, body marks, and the like of various parameters are combined with the ultrasonic image generated by the image generation unit 15a.

  The image memory 16 is a memory that stores the ultrasonic image generated by the image generation unit 15 a and the combined image generated by the image combining unit 17. The image memory 16 can also store data generated by the B-mode processing unit 13 and the Doppler processing unit 14. Note that data generated by the B-mode processing unit 13 and the Doppler processing unit 14 is also referred to as raw data.

  The internal storage unit 19 stores a control program for performing ultrasonic transmission / reception, image processing and display processing, diagnostic information (for example, patient ID, doctor's findings, etc.), various data such as a diagnostic protocol and various body marks. To do. The internal storage unit 19 is also used for storing images stored in the image memory 16 as necessary. The data stored in the internal storage unit 19 can be transferred to an external peripheral device via an interface (not shown).

  The control unit 18 controls the entire processing of the ultrasonic diagnostic apparatus. Specifically, the control unit 18 is based on various setting requests input from the operator via the input device 3 and various control programs and various data read from the internal storage unit 19. 12. Control the processing of the B-mode processing unit 13, the Doppler processing unit 14, the image processing unit 15, and the image composition unit 17. Further, the control unit 18 displays on the monitor 2 an ultrasonic image stored in the image memory 16, a GUI for designating various processes performed by the image processing unit 15, a processing result of the image processing unit 15, and the like. To control.

  The overall configuration of the ultrasonic diagnostic apparatus according to the first embodiment has been described above. With this configuration, the ultrasonic diagnostic apparatus according to the first embodiment executes the dynamic focusing method in order to increase the azimuth resolution of the ultrasonic image. Specifically, the image generation unit 15a illustrated in FIG. 1 includes reflected ultrasonic wave data added using each reception delay time calculated from a plurality of set sound speeds set as sound speeds within the imaging target region. From this, an ultrasonic image is generated for each of a plurality of set sound speeds. Hereinafter, a case where a B-mode image is generated as an ultrasound image will be described as an example. However, the present embodiment is applicable even when a Doppler image is generated as an ultrasonic image. FIG. 2 is a diagram for explaining an example of an ultrasonic image generated by the image generation unit according to the first embodiment.

  For example, it is assumed that the variable range of the set sound speed (unit: m / s) in the ultrasonic diagnostic apparatus according to the first embodiment is “1400 to 1600”. In such a case, for example, the control unit 18 changes the set sound speed every “20 m / s” in the variable range so as to generate an ultrasonic image, the transmission unit 11, the reception unit 12, and the B-mode process. The unit 13 and the image generation unit 15a are controlled. That is, the transmission unit 11 transmits an ultrasonic beam from the ultrasonic probe 1, and the reception unit 12 receives the ultrasonic probe 1 using a “reception delay time distribution” based on “set sound speed: 1400 m / s”. The reflected wave signal is added to generate reflected wave data. Then, the B mode processing unit 13 generates B mode data of “set sound speed: 1400 m / s” from the reflected wave data of “set sound speed: 1400 m / s” generated by the receiving unit 12.

  Then, as shown in FIG. 2, the image generation unit 15 a generates a B mode image of “set sound speed: 1400 m / s” from the B mode data of “set sound speed: 1400 m / s” generated by the B mode processing unit 13. Generate. By the same procedure, the image generating unit 15a, as shown in FIG. 2, “B-mode image of“ set sound speed: 1420 m / s ”, B-mode image of“ set sound speed: 1440 m / s ”,. ... “B mode image of“ set sound speed: 1600 m / s ”” is generated. An ultrasonic image for each of a plurality of set sound speeds generated by such processing is stored in the image memory 16 by the image generation unit 15a. Note that the set sound speed change range and the set sound speed interval may be stored in the internal storage unit 19 in advance or may be set by the operator when starting the image generation process. .

  Then, the detection unit 15b illustrated in FIG. 1 divides each of the ultrasonic images for each set sound speed generated by the image generation unit 15a into a plurality of sections, and the brightness value or the contrast value is optimal in the same section. Is detected for each of a plurality of sections. Specifically, the detection unit 15b corresponds to the set sound speed used for generating the ultrasonic image having the maximum luminance value or contrast value in each section of the ultrasonic images for each of the plurality of set sound speeds. Detected as “optimum set sound speed”. FIG. 3 is a diagram for explaining an example of processing by the detection unit according to the first embodiment.

  For example, when the ultrasonic scanning mode by the ultrasonic probe 1 is sector scanning, the detection unit 15b transmits an ultrasonic image in the form of a fan as shown in the left diagram of FIG. It is divided into a total of “n × m” sections of “n” along the beam transmission direction (depth direction) and “m” along the arrangement direction (azimuth direction) of the piezoelectric vibrators. In such a case, the shape of each section is as shown in the development view of the truncated cone as shown in the left diagram of FIG. In addition, when the ultrasound scanning mode by the ultrasound probe 1 is linear scanning, the detection unit 15b performs ultrasound transmission of an ultrasound image in a straight line as shown in the right diagram of FIG. It is divided into a total of “n × m” sections of “n” along the sound beam transmission direction (depth direction) and “m” along the arrangement direction (azimuth direction) of the piezoelectric vibrators. In such a case, the shape of each section is rectangular as shown in the right diagram of FIG.

  Note that the values of “n” and “m” are set by the operator when starting the processing of the detection unit 15b, even when stored in the internal storage unit 19, for example. It may be the case. For example, the size of each section determined by “n” and “m” is set based on the pixel size of the ultrasonic image. For example, the size of each section is set to a size of “5 pixels × 5 pixels”.

  Then, the detection unit 15b calculates, for example, a contrast value (such as a variance value of amplitude values) in the same section of each of the plurality of ultrasonic images.

  Then, the detection unit 15b detects a set sound speed (optimum sound speed) at which the contrast value is optimal for each section. For example, as illustrated in FIG. 3B, the detection unit 15 b is used to calculate the reception delay time by using each contrast value calculated in “section: A” of each of the ultrasonic images for each of a plurality of set sound speeds. Create a graph plotted against the set sound speed. That is, the detection unit 15b creates a graph as shown in FIG. Then, the detection unit 15b detects the set sound speed that maximizes the contrast value as the optimum sound speed in each created graph. In the example illustrated in FIG. 3B, the detection unit 15 b detects that the optimum sound speed in “section: A” is “1460 m / s”.

  Note that the detection unit 15b may execute the process illustrated in FIG. 3B by calculating a luminance value for each section. Whether the contrast value or the brightness value is used when detecting the optimum sound speed of each section is determined when the processing of the detection unit 15b is started, even if it is stored in the internal storage unit 19 in advance. It may be a case where the operator sets.

  Here, conventionally, the optimum sound speed for each section detected by the detection unit 15b is notified to the reception unit 12 via the control unit 18 in various forms as shown in FIG. FIG. 4 is a diagram for explaining a conventional technique using the detection result of the detection unit.

  For example, in the conventional technique, all the optimum sound velocities in each section shown in FIG. In such a case, the receiving unit 12 has determined the reception delay time of each focusing point based on the optimum sound speed of each section.

  Alternatively, in the conventional technique, as shown in FIG. 4B, the detection unit 15 b calculates a statistically significant optimum sound speed for each “n” depth direction section, and the depth The receiving unit 12 has been notified of the optimum sound speed for each direction. For example, the detection unit 15b may calculate the average value of the “m” optimum sound speeds or the optimum sound speed with the highest appearance frequency among the “m” optimum sound speeds for each of the “n” depth direction sections. Was calculated. In such a case, the receiving unit 12 has determined the reception delay time at each focusing point based on the optimum sound speed for each depth direction.

  Alternatively, in the conventional technique, as shown in FIG. 4C, the detection unit 15b calculates one representative optimum sound speed from the optimum sound speed for each detected section, and the one representative optimum sound speed is obtained. The reception unit 12 has been notified. For example, the detection unit 15b determines the optimum value of the optimum sound speed of each of the “n × m” sections and the optimum sound speed with the highest appearance frequency among the “n × m” optimum sound speeds in the entire image. It was calculated as the speed of sound. In such a case, the receiving unit 12 has determined the reception delay time at each focusing point based on one optimum sound speed.

  However, even if an ultrasonic image is generated using the optimum sound speed, the region of interest (ROI) that the operator wants to observe in detail in the ultrasonic imaging region in the ultrasonic imaging portion. The azimuth resolution has not always improved.

  For example, if the set sound speeds detected in each section are spatially dispersed, the “representative one optimum sound speed” described with reference to FIG. 4C is the optimum set sound speed in the region of interest. Is not necessarily. If the focal region (focal region) of the ultrasonic transmission sound field transmitted from the ultrasonic probe 1 deviates from the region of interest, the “optimum for each depth direction” described with reference to FIG. The “sound speed” and the “optimum sound speed of each section” described with reference to FIG. 4A are not necessarily the optimum set sound speed in the region of interest.

  When “optimal sound speed for each depth direction” or “optimal sound speed for each section” is used, it is conceivable to use a multi-stage focus in which a plurality of transmission focuses are set along the depth direction. However, setting the number of transmission focus stages in units of several pixels on the scan line is not practical because the processing load increases and the frame rate decreases. Further, when the region of interest is located at a short distance from the ultrasonic probe 1 in the depth direction, the optimum in the vicinity of the region of interest is caused by artifacts in the ultrasonic image caused by the generation of side lobes due to the influence of the disturbance of the transmitted sound field. In some cases, the sonic resolution cannot be detected, and the azimuth resolution of the region of interest decreases.

  Therefore, the ultrasonic diagnostic apparatus according to the first embodiment executes the process of the determination unit 15c illustrated in FIG. 1 in order to generate an ultrasonic image in which the azimuth resolution of the region of interest is always high.

  The determination unit 15c determines a set sound speed that is optimal for rendering the region of interest based on the set sound speed for each of the plurality of sections detected as optimal by the detection unit 15b. Specifically, the determination unit 15c according to the first embodiment determines a set sound speed that is optimal for rendering the region of interest set on the ultrasonic image by the operator via the input device 3.

  First, the control unit 18 reads out the ultrasonic image stored in the image memory 16 by the image generation unit 15 a and displays it on the monitor 2. Examples of the displayed ultrasound image include an initially set B-mode image having a set sound speed (such as 1500 m / s). 5 and 6 are diagrams for explaining the determination unit according to the first embodiment.

  Then, the operator refers to the monitor 2 and sets a rectangular region of interest 20 as shown in FIG. 5, for example, using the drawing function of the input device 3. In the example shown in FIG. 5, a B-mode image generated by linearly scanning the breast is displayed on the monitor 2. Note that the shape of the region of interest is not limited to a rectangle. The shape of the region of interest is set to an arbitrary shape like the region of interest 21 shown in FIG. 5, for example, by tracing the ultrasonic image by the operator using the freehand drawing function of the input device 3. It may be the case.

  Then, the determination unit 15c according to the first embodiment determines the optimum sound speed for rendering the region of interest set by the operator based on the optimum sound speed for each of the plurality of sections detected by the detection unit 15b. decide. Hereinafter, the “set sound speed that is optimal for rendering the region of interest” may be referred to as “region of interest sound speed”.

  Specifically, the determination unit 15c obtains a statistically significant value from the “optimum set sound speed (optimum sound speed)” in each of the sections including the region of interest in order to depict the region of interest. The optimum set sound speed (region of interest sound speed) is determined. For example, the determination unit 15c extracts all the sections including the region of interest 20 (see the shaded rectangle shown in FIG. 6). And the determination part 15c determines a region-of-interest sound speed by calculating | requiring a statistically significant value from the optimal sound speed of each extracted all division. For example, as illustrated in FIG. 6, the determination unit 15 c calculates an average value of the optimum sound speeds of all the extracted sections, and determines the calculated average value as the region-of-interest sound speed.

  Note that the method of calculating the region-of-interest sound speed from the optimum sound speed for each of the plurality of sections is not limited to the above average value calculation process. For example, the determination unit 15c may determine the optimum sound speed at which the number of appearances is the highest as the region-of-interest sound speed from the histogram indicating the appearance frequency of the optimum sound speed for each of all the extracted sections. Alternatively, the determination unit 15c may determine the median value of the optimum sound speeds of all the extracted sections as the region of interest sound speed.

  In the above description, the region of interest sound speed is determined from the optimum sound speed of the section including the region of interest 20. However, the determination unit 15c may determine the region of interest sound speed from the optimum sound speed of the section in the region of interest 20. It should be noted that the region of interest sound speed determination method performed by the determination unit 15c is a case where the operator sets the processing of the determination unit 15c even when the determination unit 15c starts the processing of the determination unit 15c even when the determination unit 15c is stored in advance. May be.

  In addition, even when the region of interest is set before the image generation processing for each of the plurality of set sound speeds by the image generation unit 15a, the region of interest is set after the detection processing for the optimum sound speed for each of the plurality of sections by the detection unit 15b. It may be the case.

  The control unit 18 illustrated in FIG. 1 performs control so that an ultrasonic image based on the set sound speed (region of interest sound speed) determined by the determination unit 15c is generated by the image generation unit 15a. Specifically, the control unit 18 notifies the reception delay circuit of the reception unit 12 of the region of interest sound velocity determined by the determination unit 15 c. Thereby, the reception delay circuit of the receiving unit 12 calculates the distribution of the reception delay time using the region of interest sound velocity. Then, under the control of the control unit 18, the transmission unit 11 transmits an ultrasonic beam from the ultrasonic probe 1. And the receiving part 12 produces | generates the reflected wave data with which the receiving focus was applied with respect to the region of interest using distribution of the reception delay time calculated from the region of interest sound speed. Then, the B mode processing unit 13 generates B mode data from the reflected wave data received from the receiving unit 12, and the image generating unit 15a generates a B mode image from the B mode data received from the B mode processing unit 13. . As a result, the control unit 18 displays the B-mode image on the monitor 2.

  Next, processing of the ultrasonic diagnostic apparatus according to the first embodiment will be described with reference to FIG. FIG. 7 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 7 illustrates a case where the region of interest is set before the image generation processing for each of a plurality of set sound speeds by the image generation unit 15a.

  As illustrated in FIG. 7, the ultrasonic diagnostic apparatus according to the first embodiment determines whether or not the setting of the region of interest has been received from the operator via the input device 3 (step S101). Here, when the setting of the region of interest is not accepted (No in step S101), the ultrasonic diagnostic apparatus according to the first embodiment enters a standby state.

  On the other hand, when the setting of the region of interest is received (Yes in step S101), the control unit 18 that has determined that the request for setting the region of interest sound speed has been received is configured to perform transmission and reception of ultrasonic waves based on a plurality of set sound speeds. Control (step S102). Thereafter, under the control of the control unit 18, the image generation unit 15a generates an ultrasonic image for each of a plurality of set sound speeds (step S103).

  Then, the detection unit 15b detects the optimum sound speed of each section (step S104), and the determination unit 15c determines the region of interest sound speed (step S105). For example, the determination unit 15c calculates the average value of the optimum sound speeds of all the sections including the region of interest 20, and determines the calculated average value as the region of interest sound speed.

  Subsequently, the control unit 18 performs control such that transmission / reception of ultrasonic waves is executed based on the sound speed of the region of interest (step S106), and the image generation unit 15a is controlled based on the sound speed of the region of interest by the control of the control unit 18. An ultrasonic image is generated (step S107).

  Thereafter, under the control of the control unit 18, the monitor 2 displays the ultrasonic image generated in step S107 (step S108), and the process ends.

  As described above, in the first embodiment, the image generation unit 15a uses the reception delay times calculated from a plurality of set sound speeds set as the sound speeds within the imaging target region, and adds the ultrasonic waves that have been added. An ultrasonic image for each of a plurality of set sound speeds is generated from each reflected wave data. The detection unit 15b divides each of the ultrasonic images for each of the plurality of set sound speeds generated by the image generation unit 15a into a plurality of sections, and sets the sound speed at which the luminance value or the contrast value is optimal in the same section, Detect for each of multiple partitions. Specifically, the detection unit 15b corresponds to the set sound speed used for generating the ultrasonic image having the maximum luminance value or contrast value in each section of the ultrasonic images for each of the plurality of set sound speeds. It is detected as the optimum sound speed of the section to be played.

  The determination unit 15c determines a set sound speed that is optimal for rendering the region of interest based on the set sound speed for each of the plurality of sections detected as optimal by the detection unit 15b. Specifically, the determination unit 15c determines the set sound speed that is optimal for drawing the region of interest set on the ultrasonic image by the operator via the input device 3. Note that the determination unit 15c obtains a set sound speed (region of interest sound speed) that is optimal for rendering the region of interest by, for example, obtaining a statistically significant value from the optimum sound speed of each of the sections including the region of interest. decide. The control unit 18 performs control so that an ultrasonic image based on the set sound speed determined by the determination unit 15c is generated by the image generation unit 15a.

  That is, in the first embodiment, it is possible to generate an ultrasonic image by the dynamic focusing method after determining the sound speed in the region of interest that the operator wants to observe in particular detail. Therefore, in the first embodiment, it is possible to generate an ultrasonic image in which the azimuth resolution of the region of interest is always high.

  In the above description, the case where the control unit 18 notifies the reception delay circuit of the reception unit 12 of the region of interest sound speed determined by the determination unit 15c has been described. However, the control unit 18 according to the first embodiment may also notify the region of interest sound speed determined by the determination unit 15 c to the transmission delay circuit of the transmission unit 11. In such a case, the transmission delay circuit of the transmission unit 11 calculates the transmission delay time using the region of interest sound velocity. And the transmission part 11 transmits the ultrasonic beam converged on the position of a transmission focus using the transmission delay time based on a region of interest sound velocity. As a result, not only the reception of ultrasonic waves but also the transmission of ultrasonic waves can perform delay time control using the sound speed that is optimal for rendering the region of interest, thereby further improving the azimuth resolution of the region of interest. It becomes possible.

(Second Embodiment)
In the second embodiment, a case where a region of interest is automatically set will be described.

  The ultrasonic diagnostic apparatus according to the second embodiment is configured in the same manner as the ultrasonic diagnostic apparatus according to the first embodiment described with reference to FIG. 1, but the processing by the determination unit 15c is the first embodiment. Is different. Hereinafter, this will be mainly described.

  In the second embodiment, as in the first embodiment, an ultrasonic image for each of a plurality of set sound speeds is generated, and an optimum sound speed for each of a plurality of sections is detected.

  And the determination part 15c which concerns on 2nd Embodiment uses the setting information by which the width | variety in the depth direction of the region of interest was set at least. Such setting information is stored in advance in, for example, the internal storage unit 19. That is, the internal storage unit 19 stores setting information in which the width of the region of interest is set at least in the depth direction. FIG. 8 is a diagram for explaining an example of setting information used by the determination unit according to the second embodiment.

  The information illustrated in FIG. 8 is setting information related to a region of interest when linear scanning is performed. In the example shown in FIG. 8, when the length in the azimuth direction (left-right direction) of the ultrasonic image is “X” and the length in the depth direction (vertical direction) of the ultrasonic image is “Y”, the region of interest The setting information in which the width in the azimuth direction is “X / 2” and the width in the depth direction of the region of interest is “Y / 8” is stored in the internal storage unit 19.

  Here, when an ultrasonic image is picked up by the ultrasonic diagnostic apparatus, the operator sets the position of the transmission focus as an ultrasonic transmission condition. Usually, the operator sets the transmission focus at a position in the depth direction that he wants to observe in detail. Note that as the transmission condition, in addition to the position of the transmission focus, the number of piezoelectric vibrators (transmission numerical aperture) used at the time of transmission to form an ultrasonic beam in each scan line, the transmission frequency, and the like are set.

  The determination unit 15 c according to the second embodiment sets a region of interest with reference to the setting information stored in the internal storage unit 19 for the transmission focus position set by the operator via the input device 3. Then, the determination unit 15c according to the second embodiment determines a set sound speed (region of interest sound speed) that is optimal for drawing the set region of interest. FIG. 9 is a diagram for explaining a determination unit according to the second embodiment.

  For example, as shown in FIG. 9A, it is assumed that the operator sets the transmission focus at the position of “scale in the depth direction: 2” synthesized by the image synthesizing unit 17 on the ultrasonic image. In such a case, for example, the determination unit 15c extracts the intersection point between the straight line in the azimuth direction passing through “scale in the depth direction: 2” and the center line in the azimuth direction of the ultrasonic image. Then, with the extracted intersection as the center, the determining unit 15c has a width in the azimuth direction of “X / 2” and a width in the depth direction of “Y / 8” as illustrated in FIG. 9A. A region of interest 30 is set.

  And the determination part 15c determines the region of interest sound speed in the region of interest 30 by the process similar to 1st Embodiment. Then, under the control of the control unit 18, the transmission unit 11 performs transmission of an ultrasonic beam having a transmission focus at the position of “scale in the depth direction: 2”, and the reception unit 12 is based on the sound velocity of the region of interest. Then, the reflected wave data in which the reception focus is applied to the region of interest 30 is generated. Thereby, the image generation unit 15a generates an ultrasonic image based on the sound speed of the region of interest, and the monitor 2 displays the ultrasonic image.

  Note that the determination unit 15c according to the second embodiment can also set a plurality of regions of interest based on a plurality of transmission focus positions.

  For example, when multi-stage focusing is performed, the operator sets the number of transmission focus stages and the position of each transmission focus as ultrasonic transmission conditions.

  For example, as shown in FIG. 9B, the operator has two positions “scale in the depth direction: 2” and “scale in the depth direction: 3” synthesized by the image composition unit 17 on the ultrasonic image. Suppose you set the send focus. In this case, the determination unit 15c sets the region of interest 30 for “scale in the depth direction: 2” as illustrated in FIG. 9B. Further, the determination unit 15c, as shown in FIG. 9B, centering on the intersection of the straight line in the azimuth direction passing through the “scale in the depth direction: 3” and the center line in the azimuth direction of the ultrasonic image. The region of interest 31 in which the width in the azimuth direction is “X / 2” and the width in the depth direction is “Y / 8” is set.

  And the determination part 15c determines the region-of-interest sound speed in the region of interest 30 and the region-of-interest sound speed in the region of interest 31 by the process similar to 1st Embodiment, respectively. Here, when multistage focusing is performed, the ultrasound diagnostic apparatus generates an ultrasound image focused on each transmission focus.

  Therefore, in the case illustrated in FIG. 9B, the transmission unit 11 causes the transmission of the ultrasonic beam with the position of “scale in the depth direction: 2” as the transmission focus by the control of the control unit 18, The receiving unit 12 generates reflected wave data in which the reception focus is applied to the region of interest 30 based on the region of interest sound speed of the region of interest 30. Further, under the control of the control unit 18, the transmission unit 11 performs transmission of an ultrasonic beam having a transmission focus at a position of “scale in the depth direction: 3”, and the reception unit 12 performs a region of interest in the region of interest 31. Based on the speed of sound, the reflected wave data in which the reception focus is applied to the region of interest 31 is generated. Thereby, the image generation unit 15 a generates an ultrasonic image based on the region of interest sound speed in the region of interest 30 and an ultrasonic image based on the region of interest sound speed in the region of interest 31. Hereinafter, an ultrasonic image based on the region of interest sound speed in the region of interest 30 is referred to as a “first image”, and an ultrasonic image based on the region of interest sound speed in the region of interest 31 is referred to as a “second image”. That is, the first image is an ultrasonic image with a high azimuth resolution of the region of interest 30. Further, the second image is an ultrasonic image having a high orientation resolution of the region of interest 31.

  Here, under the control of the control unit 18, the image composition unit 17 generates a composite image in which the upper region of the first image including the region of interest 30 and the lower region of the second image including the region of interest 31 are combined. Then, under the control of the control unit 18, the monitor 2 displays the composite image generated by the image composition unit 17. Alternatively, the first image and the second image are displayed in parallel on the monitor 2 under the control of the control unit 18.

  Note that the determination unit 15c determines the sound speed of one region of interest after resetting a plurality of regions of interest as one region of interest even when a plurality of regions of interest are set by setting a plurality of transmission focuses. May be. For example, the determination unit 15c resets the region of interest 30 and the region of interest 31 to the region of interest 32 as illustrated in FIG. Here, the width in the depth direction of the region of interest 32 is a range sandwiched between the upper side of the region of interest 30 and the lower side of the region of interest 31. Further, the width of the region of interest 32 in the azimuth direction is a range sandwiched between the left side and the right side of the region of interest 30 and the region of interest 31. And the determination part 15c determines the region-of-interest sound speed in the region of interest 32 by the process similar to 1st Embodiment.

  In such a case, under the control of the control unit 18, the transmission unit 11 performs transmission of an ultrasonic beam having a transmission depth at the position of “scale in the depth direction: 2”, and the reception unit 12 is interested in the region of interest 32. Reflected wave data is generated based on the regional sound speed. Further, under the control of the control unit 18, the transmission unit 11 performs transmission of an ultrasonic beam having a transmission focus at the position of “scale in the depth direction: 3”, and the reception unit 12 performs the region of interest in the region of interest 32. Based on the speed of sound, reflected wave data is generated. Thereby, the image generation unit 15a generates an ultrasonic image with a high azimuth resolution of the region of interest 30 and an ultrasonic image with a high azimuth resolution of the region of interest 31 based on the region of interest sound speed of the region of interest 32. Here, as described above, the display form of the ultrasound image when resetting a plurality of regions of interest to one region of interest is parallel display of each ultrasound image even if the composite image is displayed alone. May be.

  Further, the second embodiment is not limited to the case where a plurality of regions of interest are reset to one region of interest. For example, in the second embodiment, four regions of interest set from four transmission focus positions may be reset to two regions of interest by integrating two regions of interest according to depth. . In such a case, the determination unit 15c determines the region of interest sound speed from each of the two regions of interest.

  As described above, the determination unit 15c according to the second embodiment can perform processing of three patterns when a plurality of regions of interest are set based on a plurality of transmission focus positions. That is, in the first pattern, the determination unit 15c determines the region of interest sound speed for each of the plurality of regions of interest. In the second pattern, the determination unit 15c determines one region-of-interest sound speed after resetting a plurality of regions of interest to one. Further, in the third pattern, the determination unit 15c determines the region-of-interest sound speed of each reset region of interest after resetting a plurality of regions of interest to a number of regions of interest less than the transmission focus number. Note that the setting of whether to execute one of the first to third patterns is set by the operator when starting the processing of the determination unit 15c, even when stored in the internal storage unit 19 in advance. It may be the case. Further, the display form in the multistage focus can be selected by the operator.

  In the above description, a rectangular region of interest is set as illustrated in FIGS. 8 and 9. However, in the second embodiment, the shape of the region of interest set in the setting information may be an arbitrary shape such as an ellipse. In the above description, as illustrated in FIG. 8, the case has been described in which regions of interest having the same size are set according to the position of the transmission focus. However, in the second embodiment, for example, the setting information may be set so that the size of the region of interest increases as the depth of transmission focus increases.

  Note that the setting information when sector scanning is performed is set as illustrated in FIG. 10, for example. FIG. 10 is a diagram for explaining another example of the setting information used by the determination unit according to the second embodiment.

  For example, when sector scanning is performed, a range between two scan lines near the center (refer to the dotted line shown in FIG. 10) in the scan line scanned in a sector shape is set in the azimuth direction of the region of interest. Setting information as a width is stored in the internal storage unit 19. When sector scanning is performed, setting information set so that the width of the region of interest in the depth direction increases as the transmission focus depth increases as shown in FIG. 19.

  In the above description, the case where the depth direction and the width in the azimuth direction of the region of interest are set in the setting information has been described. However, the width set in the setting information may be only in the depth direction of the region of interest. In such a case, the width of the region of interest in the azimuth direction is set by the operator.

  Further, even when the setting of the region of interest accompanying the setting of the transmission focus is performed before the image generation processing for each of the plurality of set sound speeds by the image generation unit 15a, the optimum sound speed for each of the plurality of sections by the detection unit 15b. It may be performed after the detection process.

  Next, processing of the ultrasonic diagnostic apparatus according to the second embodiment will be described with reference to FIG. FIG. 11 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the second embodiment. Note that FIG. 12 illustrates a case where the region of interest setting associated with the transmission focus setting is performed before the image generation processing for each of a plurality of set sound speeds by the image generation unit 15a.

  As illustrated in FIG. 11, the ultrasonic diagnostic apparatus according to the second embodiment determines whether or not a transmission focus setting has been received from the operator via the input device 3 (step S <b> 201). If the transmission focus setting is not accepted (No at Step S201), the ultrasonic diagnostic apparatus according to the second embodiment is in a standby state.

  On the other hand, when the setting of the transmission focus is accepted (Yes at Step S201), the determination unit 15c refers to the setting information and sets the region of interest at the position of the transmission focus (Step S202).

  And the control part 18 is controlled so that transmission / reception of an ultrasonic wave is performed based on several setting sound speed (step S202). Thereafter, under the control of the control unit 18, the image generation unit 15a generates an ultrasonic image for each of a plurality of set sound speeds (step S204).

  Then, the detection unit 15b detects the optimum sound speed of each section (step S205), and the determination unit 15c determines the region of interest sound speed (step S206).

  Subsequently, the control unit 18 performs control so that transmission / reception of ultrasonic waves is executed based on the sound speed of the region of interest (step S207), and the image generation unit 15a is controlled based on the sound speed of the region of interest by the control of the control unit 18. An ultrasonic image is generated (step S208).

  Thereafter, under the control of the control unit 18, the monitor 2 displays the ultrasonic image generated in step S208 (step S209), and the process ends.

  As described above, in the second embodiment, the internal storage unit 19 stores setting information in which the width of the region of interest is set at least in the depth direction. Then, the determination unit 15c sets a region of interest with reference to the setting information stored in the internal storage unit 19 for the position of the transmission focus set by the operator via the input device 3, and the set region of interest Determines the sound speed that is optimal for rendering.

  That is, in the second embodiment, the region of interest for determining the region of interest sound speed can be automatically set based on the transmission focus information set by the operator. Therefore, in the second embodiment, it is possible to reduce the burden on the operator in photographing an ultrasonic image with a high orientation resolution of the region of interest.

  In the second embodiment, the determination unit 15c sets a plurality of regions of interest based on a plurality of transmission focus positions. Specifically, in the second embodiment, when the determination unit 15c sets a plurality of regions of interest by accepting a shooting request with multistage focus, any one of the first to third patterns described above is set. One or more region-of-interest sound speeds are determined by processing. Even when any one of the first to third patterns is executed, according to the second embodiment, it is possible to generate an ultrasonic image having a high azimuth resolution of a plurality of regions of interest.

(Third embodiment)
In the third embodiment, a case will be described in which a region of interest is automatically set by a method different from that of the second embodiment.

  The ultrasonic diagnostic apparatus according to the third embodiment is configured similarly to the ultrasonic diagnostic apparatus according to the first embodiment described with reference to FIG. However, the determination unit 15c according to the third embodiment sets a region of interest by a method different from the determination unit 15c according to the second embodiment. Hereinafter, this will be mainly described.

  In the third embodiment, as in the first embodiment, an ultrasonic image for each of a plurality of set sound speeds is generated, and an optimum sound speed for each of a plurality of sections is detected.

  Then, the determination unit 15c according to the third embodiment determines the focal region of the ultrasonic wave transmitted from the ultrasonic probe based on the transmission sound field calculated from the ultrasonic transmission condition including the transmission focus position information. To do. And the determination part 15c which concerns on 3rd Embodiment sets the area | region in the determined focal area as a region of interest.

  Here, as described above, ultrasonic transmission conditions set by the operator include transmission focus position information, transmission numerical aperture, and transmission frequency. When such transmission conditions are set, the profile of the ultrasonic beam transmitted from the ultrasonic probe 1 can be approximately calculated. FIG.12 and FIG.13 is a figure for demonstrating the determination part which concerns on 3rd Embodiment.

For example, from the transmission focus position information set by the operator via the input device 3, the determination unit 15c calculates the distance “F ₀ ” from the ultrasonic probe 1 of the transmission focus. That is, “F ₀ ” is the distance in the depth direction of the transmission focus. Also, the transmission aperture width “D” is calculated from the transmission numerical aperture set by the operator via the input device 3 and the “pitch width of the piezoelectric vibrator” which is a known value. Further, the wavelength “λ” of the ultrasonic beam is calculated from the transmission frequency set by the operator via the input device 3.

And the determination part 15c draws the simple sound field which approximated the transmission sound field as shown in FIG. 12, for example by a simple drawing method. Here, “W” shown in FIG. 12 is the beam width of “−20 dB (decibel)” in “F ₀ ”, and the determination unit 15 c sets “W = 2 × F ₀ × (λ / D)”. calculate. Then, as illustrated in FIG. 12, the determination unit 15 c sets a transmission focus point 41 on the half line 40 parallel to the depth direction starting from the center of the transmission aperture width based on the distance “F ₀ ”. . Then, the determination unit 15c sets a line segment having a width “W” with the transmission focus point 41 as the center (refer to the line segment with arrows at both ends shown in FIG. 12).

  Then, as illustrated in FIG. 12, the determination unit 15c sets a half line 42 and a half line 43 that pass through both ends of the line segment set as described above, starting from the center of the transmission aperture width. Here, the angle between the half line 40 and the half line 42 (and the angle between the half line 40 and the half line 43) is a directivity angle.

  Then, as illustrated in FIG. 12, the determination unit 15 c sets a half line 44 that starts from the upper end of the transmission aperture and passes through the transmission focus point 41. Further, as illustrated in FIG. 12, the determination unit 15 c sets a half line 45 that starts from the lower end of the transmission opening and passes through the transmission focus point 41. And the determination part 15c makes the line segment group (refer the thick line shown in FIG. 12) located outside the range determined by the half line 42-half line 45 the simple sound field which approximated the transmission sound field. .

Then, the determination unit 15c determines a straight line passing through the intersection of the half line 42 and the half line 44 and the intersection of the half line 43 and the half line 45 as the shallowest part of the focal region, and the shallowest part of the focal region. And the center of the transmission aperture width is calculated as “X ₁ ”. Further, the determination unit 15c determines a straight line passing through the intersection of the half line 42 and the half line 45 and the intersection of the half line 43 and the half line 44 as the deepest part of the focal region, The distance from the center of the transmission aperture width is calculated as “X ₂ ”. That is, the determination unit 15c determines the range in the depth direction in which the distance from the ultrasonic probe 1 is “X ₁ ” to “X ₂ ” as the focal region.

In addition, the simple sound field shown in FIG. 12 has shown the focal area in one ultrasonic beam. Therefore, in the case of linear scanning, the range in the depth direction where the distance from the straight line on which the piezoelectric vibrators are arranged is from “X ₁ ” to “X ₂ ” is the focal range. In the case of sector scanning, the distance from the piezoelectric vibrator located at the center of the transmission aperture for each ultrasonic beam is changed from “X ₁ ” to “X” in accordance with the transmission direction of the ultrasonic beam scanned in a fan shape. The range in the depth direction at ₂ ”is the focal zone.

Then, the determination unit 15c sets the determined region in the focal region as the region of interest. For example, as illustrated in FIG. 13, the determination unit 15 c determines the range in the depth direction in which the distance from the straight line on which the piezoelectric vibrators are arranged from “X ₁ ” to “X ₂ ”, Set as the width of. Note that the width of the region of interest in the azimuth direction can be arbitrarily set by the operator. For example, if the length of the ultrasonic image in the azimuth direction is “X”, the determination unit 15c sets the width of the region of interest in the azimuth direction as “X / 2”.

  Then, the determination unit 15c determines the region of interest sound speed in the same manner as in the first embodiment, and the control unit 18 performs control so that an ultrasound image is generated based on the region of interest sound speed.

  Note that the determination unit 15c according to the third embodiment can also set a plurality of regions of interest based on a plurality of transmission focus positions, as in the second embodiment.

  For example, when two transmission focus positions are set, the determination unit 15c draws a simple sound field based on the respective transmission focus positions. Thereby, the determination part 15c determines the focal area in each of two transmission focus, and sets two regions of interest. That is, the determination unit 15c determines a range between the shallowest part and the deepest part of the focal area determined for one of the two transmission focuses in the depth direction of the region of interest corresponding to the transmission focus. Set as width. In addition, the determination unit 15c sets, in the depth direction of the region of interest corresponding to the transmission focus, the range sandwiched between the shallowest part and the deepest part of the focal area determined for the other transmission focus among the two transmission focuses. Set as width. Accordingly, the determination unit 15c sets two regions of interest as illustrated in FIG. 9B, for example.

  Note that when a plurality of regions of interest are set, the determination unit 15c performs either the first pattern, the second pattern, or the third pattern as described in the second embodiment. .

In the above description, the range between the shallowest part and the deepest part of the focal range is set as the width in the depth direction of the region of interest corresponding to the transmission focus. However, the determination unit 15c according to the second embodiment sets a partial range between the shallowest portion and the deepest portion of the focal region as the width in the depth direction of the region of interest corresponding to the transmission focus. You may do it. For example, the determination unit 15c may set the depth direction range from “X ₁ + a” to “X ₂ -b” as the width in the depth direction of the region of interest corresponding to the transmission focus. “A” and “b” are numerical values that can be arbitrarily set by the operator.

  Further, even when the setting of the region of interest accompanying the setting of the transmission condition is performed before the image generation processing for each of the plurality of set sound speeds by the image generation unit 15a, the optimum sound speed for each of the plurality of sections by the detection unit 15b. It may be performed after the detection process.

  Next, processing of the ultrasonic diagnostic apparatus according to the third embodiment will be described with reference to FIG. FIG. 14 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the third embodiment. FIG. 14 illustrates a case where the region of interest setting associated with the transmission condition setting is performed before the image generation processing for each of a plurality of set sound speeds by the image generation unit 15a.

  As illustrated in FIG. 14, the ultrasonic diagnostic apparatus according to the third embodiment determines whether a transmission condition setting has been received from the operator via the input device 3 (step S <b> 301). Here, when the transmission condition setting is not accepted (No at Step S301), the ultrasonic diagnostic apparatus according to the third embodiment is in a standby state.

  On the other hand, when the setting of the transmission condition is accepted (Yes at Step S301), the determination unit 15c calculates the transmission sound field from the transmission condition and determines the focal range (Step S302). Then, the determination unit 15c sets a region in the focal region as a region of interest (Step S303).

  And the control part 18 is controlled so that transmission / reception of an ultrasonic wave is performed based on several setting sound speed (step S304). Thereafter, under the control of the control unit 18, the image generation unit 15a generates an ultrasonic image for each of a plurality of set sound speeds (step S305).

  Then, the detection unit 15b detects the optimum sound speed of each section (step S306), and the determination unit 15c determines the region of interest sound speed (step S307).

  Subsequently, the control unit 18 performs control so that transmission / reception of ultrasonic waves is executed based on the sound speed of the region of interest (step S308), and the image generation unit 15a is controlled based on the sound speed of the region of interest by the control of the control unit 18. An ultrasonic image is generated (step S309).

  Thereafter, under the control of the control unit 18, the monitor 2 displays the ultrasonic image generated in step S309 (step S310) and ends the process.

  As described above, in the third embodiment, the determination unit 15c determines the ultrasonic wave transmitted from the ultrasonic probe based on the transmission sound field calculated from the ultrasonic transmission condition including the transmission focus position information. A focal area is determined, and an area within the determined focal area is set as a region of interest.

  As described above, in the third embodiment, based on the position of the transmission focus, the region of interest is not simply set, but the focal region to which the transmission focus is applied at the time of setting the region of interest is determined. Sets the width of the region of interest in the depth direction. That is, in the third embodiment, the region-of-interest sound speed of the region of interest that is transmission-focused can be determined. Therefore, in the third embodiment, the azimuth resolution of the region of interest can be further improved.

  In the third embodiment, the determination unit 15c sets a plurality of regions of interest based on a plurality of transmission focus positions. Specifically, in the third embodiment, when receiving an imaging request with multistage focus, the determination unit 15c sets a plurality of regions of interest after determining the focal region of each transmission focus point. Therefore, according to the third embodiment, it is possible to generate an ultrasonic image having a high azimuth resolution of a plurality of regions of interest.

(Fourth embodiment)
In the fourth embodiment, a case where transmission conditions for generating an ultrasonic image used for detecting the optimum sound speed are determined based on the region of interest set in the first embodiment or the second embodiment. explain.

  The ultrasonic diagnostic apparatus according to the fourth embodiment is configured similarly to the ultrasonic diagnostic apparatus according to the first embodiment described with reference to FIG. However, the determination unit 15c according to the fourth embodiment further executes the following processing in addition to the processing described in the first embodiment or the second embodiment.

  For example, in the fourth embodiment, as described in the first embodiment, the operator manually sets the region of interest.

  Then, when the determination unit 15c according to the fourth embodiment generates an ultrasonic image for each of a plurality of set sound velocities, the determination unit 15c is supersonic so that the focal region of the ultrasonic wave transmitted from the ultrasonic probe 1 includes the region of interest. Determine the sound wave transmission conditions. FIG. 15 is a diagram for explaining a determination unit according to the fourth embodiment.

For example, as shown in FIG. 15, it is assumed that the operator has set the region of interest 50 on the ultrasonic image. In such a case, the determination unit 15c uses the simple sound field drawing method described in the third embodiment, so that the focal region is included in the depth direction of the region of interest 50, The position of the transmission focus and the transmission aperture are determined. That is, the determination unit 15c draws a simple sound field in which “D” and “F ₀ ” are changed after fixing the wavelength “λ” calculated from the transmission frequency. Thereby, for example, as illustrated in FIG. 15, the determination unit 15c includes the transmission aperture width “D53” and the range in the depth direction of the first focal region by the transmission focus point “F51”, the transmission aperture width “D54”, and It is determined that the range of the region of interest 50 in the depth direction is covered by overlapping the range of the second focal region in the depth direction by the transmission focus point “F52”. In other words, the determination unit 15c determines that the range sandwiched between the shallowest portion of the first focal region and the deepest portion of the second focal region matches the range of the region of interest 50 in the depth direction.

  In such a case, the determination unit 15c determines that the transmission focus stage number is “2”. Then, the determination unit 15c determines the transmission aperture based on the transmission aperture width “D53” and the position of the transmission focus based on the position of the transmission focus point “F51” as the first transmission condition. Further, the determination unit 15c determines the transmission aperture based on the transmission aperture width “D54” and the position of the transmission focus based on the position of the transmission focus point “F52” as the second transmission condition. Note that a value obtained by dividing the depth of the transmission focus by the transmission aperture width is used as a value indicating the strength of the transmission focus, and is referred to as “transmission Fnumber”, for example.

  The first transmission condition and the second transmission condition are notified from the determination unit 15c to the control unit 18, and the control unit 18 notifies the transmission unit 11 of the first transmission condition and the second transmission condition. Thereby, the transmission unit 11 performs transmission control of the ultrasonic beam based on the first transmission condition and the second transmission condition when generating an ultrasonic image of each set sound velocity. Then, the reception unit 12 generates the reflected wave data of the first transmission condition and the reflected wave data of the second transmission condition based on the distribution of the reception delay time using the corresponding set sound speed. Thereby, the image generation unit 15a generates an ultrasonic image of the first transmission condition and an ultrasonic image of the second transmission condition for each of a plurality of set sound speeds. Then, the image synthesis unit 17 generates a synthesized image by synthesizing the ultrasonic image under the first transmission condition and the ultrasonic image under the second transmission condition for each of a plurality of set sound speeds.

  Then, the detection unit 15b divides each of the composite images for each of the plurality of set sound speeds into a plurality of sections, and sets the set sound speed (optimum sound speed) at which the luminance value or the contrast value is optimal in the same section as the plurality of sections. Detect every time.

  Then, the determination unit 15c determines a setting sound speed (region of interest sound speed) that is optimal for rendering the region of interest 50 from the detection result of the detection unit 15b, and the control unit 18 sets the setting determined by the determination unit 15c. Control is performed so that an ultrasonic image based on the speed of sound is generated by the image generation unit 15a.

  Depending on the size of the region of interest 50, the position of the transmission focus may be one. In such a case, the optimum sound speed of each section is determined from an ultrasonic image for each of a plurality of set sound speeds according to one transmission condition. Detected.

  In addition, the determination unit 15c according to the fourth embodiment determines a transmission condition for generating an ultrasonic image for each set sound speed based on the region of interest determined based on the position of the transmission focus and the setting information. You can do it. In such a case, the determination unit 15c fixes the transmission focus position set by the operator and determines the transmission condition by, for example, plotting a simple sound field in which “D” and “λ” are changed. . When the operator sets a plurality of transmission focus positions, the determination unit 15c determines transmission conditions for each of the plurality of regions of interest.

  Next, processing of the ultrasonic diagnostic apparatus according to the fourth embodiment will be described with reference to FIG. FIG. 16 is a flowchart for explaining processing of the ultrasonic diagnostic apparatus according to the fourth embodiment. FIG. 16 illustrates a case where the region of interest is manually set by the operator.

  As illustrated in FIG. 16, the ultrasonic diagnostic apparatus according to the fourth embodiment determines whether a region of interest setting has been received from the operator via the input device 3 (step S <b> 401). Here, when the setting of the region of interest is not accepted (No at Step S401), the ultrasonic diagnostic apparatus according to the fourth embodiment enters a standby state.

  On the other hand, when the setting of the region of interest is accepted (Yes at Step S401), the determination unit 15c determines the ultrasound transmission condition so that the focal region includes the region of interest (Step S402). Specifically, the transmission condition is determined so that the focal region in the depth direction of the transmission sound field covers the width of the region of interest in the depth direction.

  And the control part 18 is controlled so that transmission / reception of an ultrasonic wave is performed based on the transmission conditions and the several setting sound speed determined by the determination part 15c (step S403). Thereafter, under the control of the control unit 18, the image generation unit 15a generates an ultrasonic image for each of a plurality of set sound speeds (step S404).

  Then, the detection unit 15b detects the optimum sound speed of each section (step S407), and the determination unit 15c determines the region of interest sound speed (step S406). When the transmission condition is multistage focus, the image used for the optimum sound speed detection process of the detection unit 15b is a composite image.

  Subsequently, the control unit 18 performs control such that transmission / reception of ultrasonic waves is executed based on the sound speed of the region of interest (step S407). Under the control of the control unit 18, the image generation unit 15a is based on the sound speed of the region of interest. An ultrasonic image is generated (step S408).

  Thereafter, under the control of the control unit 18, the monitor 2 displays the ultrasonic image generated in step S408 (step S409), and the process ends.

  As described above, in the fourth embodiment, when the determination unit 15c generates an ultrasonic image for each of a plurality of set sound speeds, the focal region of the ultrasonic wave transmitted from the ultrasonic probe 1 represents the region of interest. Ultrasonic transmission conditions are determined so as to include them.

  In other words, in the fourth embodiment, a transmission condition is set so that the region of interest is the focal region of the ultrasonic beam, and then an ultrasonic image group for detecting the optimum sound speed is generated. In the fourth embodiment, by using such a group of ultrasonic images, the accuracy of detection of the optimum sound speed of each section is improved, and as a result, the reliability of the sound speed of the region of interest determined by the determination unit 15c can be improved. It becomes possible.

  The image generation control method executed by the ultrasonic diagnostic apparatus described in the first to fourth embodiments is to execute an image generation control program prepared in advance on a computer such as a personal computer or a workstation. Can be realized. This image generation control program can be distributed via a network such as the Internet. The image generation control program may be recorded on a computer-readable recording medium such as a hard disk, a flexible disk (FD), a CD-ROM, an MO, or a DVD, and executed by being read from the recording medium by the computer. it can.

  As described above, according to the first to fourth embodiments, it is possible to generate an ultrasound image in which the azimuth resolution of the region of interest is always high.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Ultrasonic probe 2 Monitor 3 Input device 10 Apparatus main body 11 Transmission part 12 Reception part 13 B mode processing part 14 Doppler processing part 15 Image processing part 15a Image generation part 15b Detection part 15c Determination part 16 Image memory 17 Image composition part 18 Control Part 19 Internal storage

Claims (9)

An ultrasonic image is generated for each of the plurality of set sound speeds from each of reflected ultrasonic wave data added using each reception delay time calculated from a plurality of set sound speeds set as sound speeds within the imaging target region. An image generator;
Each of the ultrasonic images for each of the plurality of set sound speeds generated by the image generation unit is divided into a plurality of sections, and the set sound speed at which the luminance value or the contrast value is optimal in the same section is determined as the plurality of sections. A detection unit for detecting each,
A determination unit that determines a set sound speed that is optimal for rendering a region of interest based on a set sound speed for each of the plurality of sections detected as optimal by the detection unit;
A control unit that controls an ultrasonic image based on the set sound velocity determined by the determination unit to be generated by the image generation unit;
An ultrasonic diagnostic apparatus comprising:   The super-determining unit according to claim 1, wherein the determining unit determines a set sound speed that is optimal for rendering a region of interest set on an ultrasonic image by an operator via a predetermined input unit. Ultrasonic diagnostic equipment.   The detection unit detects the set sound speed used to generate the ultrasonic image having the maximum luminance value or contrast value in each section of the ultrasonic images for each of the plurality of set sound speeds in the corresponding section. The ultrasonic diagnostic apparatus according to claim 1, wherein the ultrasonic diagnostic apparatus is detected as an optimal set sound speed.   The determination unit determines a set sound speed that is optimal for rendering the region of interest by obtaining a statistically significant value from the set sound speed that is optimal for each of the sections including the region of interest. The ultrasonic diagnostic apparatus according to claim 1, wherein the apparatus is an ultrasonic diagnostic apparatus. A setting information storage unit for storing setting information in which a width in the depth direction of the region of interest is set;
The determination unit sets a region of interest with reference to the setting information stored in the setting information storage unit with respect to the position of the transmission focus set by the operator via a predetermined input unit, and the set interest The ultrasonic diagnostic apparatus according to claim 1, wherein a set sound speed that is optimal for rendering an area is determined.   The determination unit determines a focal region of an ultrasonic wave transmitted from the ultrasonic probe based on a transmission sound field calculated from an ultrasonic transmission condition including transmission focus position information, and a region within the determined focal region The ultrasonic diagnostic apparatus according to claim 1, wherein: is set as the region of interest.   The ultrasonic diagnostic apparatus according to claim 5, wherein the determination unit sets a plurality of regions of interest based on a plurality of transmission focus positions.   The determination unit determines an ultrasonic transmission condition so that a focal area of an ultrasonic wave transmitted from an ultrasonic probe includes the region of interest when generating an ultrasonic image for each of the plurality of set sound speeds. The ultrasonic diagnostic apparatus according to claim 2 or 5. An ultrasonic image for each of the plurality of set sound speeds generated from each of reflected ultrasonic wave data added using each reception delay time calculated from a plurality of set sound speeds set as sound speeds in the imaging target region. A detection procedure for dividing the plurality of sections and detecting a set sound speed at which the brightness value or the contrast value is optimal in the same section for each of the plurality of sections;
A determination procedure for determining a set sound speed that is optimal for rendering a region of interest based on a set sound speed for each of the plurality of sections detected as being optimal by the detection procedure;
A control procedure for controlling to generate an ultrasonic image based on the set sound speed determined by the determination procedure;
An image generation control program for causing a computer to execute.

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