JP5931414B2 - Ultrasonic diagnostic apparatus, image generation method, and image processing apparatus - Google Patents

Description

  Embodiments described herein relate generally to an ultrasonic diagnostic apparatus, an image generation method, and an image processing apparatus.

  2. Description of the Related Art Conventionally, an ultrasonic diagnostic apparatus is an apparatus having advantages such as simple operability and non-invasiveness that does not cause exposure, compared to other medical image diagnostic apparatuses such as an X-ray diagnostic apparatus and an X-ray computed tomography apparatus. In today's medical care, it is used for examination and diagnosis of various living tissues such as heart, liver, kidney and mammary gland.

  Such an ultrasonic diagnostic apparatus transmits an ultrasonic wave from an ultrasonic probe and receives a reflected wave signal reflected from the internal tissue of the subject, thereby obtaining a tomographic image (B-mode image) of the tissue structure in the subject. ) In real time. Furthermore, recent ultrasound diagnostic apparatuses can distinguish blood flow information such as blood flow velocity, dispersion, power, etc. by color, using the Doppler effect of ultrasound, as well as the blood flow in the subject. A color Doppler image to be displayed is generated in real time. Further, blood flow information is quantitatively analyzed using such color Doppler images.

JP-A-6-3197737 US Pat. No. 6,224,557

  However, in the conventional ultrasonic diagnostic apparatus, different color Doppler images may be generated by setting operations by an operator. Specifically, the ultrasound diagnostic apparatus calculates the blood flow information using the Doppler shift frequency of the ultrasound after gain correction of the reception signal received by the ultrasound probe with a predetermined color gain. For this reason, the conventional ultrasonic diagnostic apparatus generates color Doppler images having different color displays depending on the color gain set by the operator or the like even if the same part of the same subject is imaged. There was a thing.

  The ultrasonic diagnostic apparatus according to the embodiment includes a movement information acquisition unit, an image generation unit, an index calculation unit, a gain selection unit, and a control unit. The movement information acquisition unit obtains movement information by correcting the reception signal received by the ultrasonic probe with a gain. An image generation part performs the process which produces | generates the color image which allocated the color pixel based on the said movement information. The index calculation unit obtains an index value indicating the distribution of the color pixels based on a plurality of color images generated by the image generation unit. The gain selection unit selects a display gain based on the comparison of the index values obtained for a plurality of gains. The control unit controls the image generation unit to generate a color image to which color pixels are allocated based on the display gain and movement information obtained from the received signal.

FIG. 1 is a block diagram illustrating a configuration example of the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 2 is a diagram illustrating an example of a color Doppler image. FIG. 3 is a diagram illustrating an example of a color Doppler image. FIG. 4 is a block diagram illustrating a configuration example of the control unit in the first embodiment. FIG. 5 is a diagram illustrating an example of the pixel rate storage unit. FIG. 6 is a diagram illustrating a relationship example between the color gain and the color pixel rate. FIG. 7 is a diagram illustrating an example of the pixel number storage unit. FIG. 8 is a diagram illustrating an example of the relationship between the passage of time and the number of color pixels. FIG. 9 is a flowchart illustrating a processing procedure performed by the ultrasonic diagnostic apparatus according to the first embodiment. FIG. 10 is a flowchart illustrating an optimal gain selection processing procedure by the gain selection unit in the first embodiment. FIG. 11 is a flowchart illustrating an optimal image selection processing procedure by the image selection unit in the first embodiment. FIG. 12 is a diagram illustrating a relationship example between the color gain and the color pixel rate. FIG. 13 is a block diagram illustrating a configuration example of a control unit in the second embodiment. FIG. 14 is a diagram illustrating an example of a cutoff frequency storage unit. FIG. 15 is a flowchart illustrating a processing procedure performed by the ultrasonic diagnostic apparatus according to the second embodiment. FIG. 16 is a block diagram illustrating a configuration example of a control unit in the third embodiment. FIG. 17 is a diagram illustrating an example of the optimum color gain storage unit. FIG. 18 is a flowchart illustrating an optimal gain selection processing procedure performed by the ultrasonic diagnostic apparatus according to the third embodiment. FIG. 19 is a block diagram illustrating a configuration example of a control unit in the fourth embodiment. FIG. 20 is a flowchart illustrating a processing procedure performed by the ultrasonic diagnostic apparatus according to the fourth embodiment. FIG. 21 is a flowchart illustrating an optimal gain selection processing procedure by the gain selection unit according to the fourth embodiment. FIG. 22 is a diagram illustrating a configuration example of an image processing system.

(First embodiment)
First, the configuration of the ultrasonic diagnostic apparatus according to the first embodiment will be described. FIG. 1 is a block diagram illustrating a configuration example of the ultrasonic diagnostic apparatus according to the first embodiment. As illustrated in FIG. 1, the ultrasonic diagnostic apparatus 1 according to the first embodiment includes an ultrasonic probe 10, an input apparatus 20, a monitor 30, and an apparatus main body 100.

  The ultrasonic probe 10 includes a plurality of piezoelectric vibrators, and the plurality of piezoelectric vibrators generate ultrasonic waves based on a drive signal supplied from an ultrasonic transmission unit 110 included in the apparatus main body 100 described later. The ultrasonic probe 10 receives a reflected wave signal from the subject P and converts it into an electrical signal. The ultrasonic probe 10 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. The ultrasonic probe 10 is detachably connected to the apparatus main body 100.

  When ultrasonic waves are transmitted from the ultrasonic probe 10 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 as a reflected wave signal Received by a plurality of piezoelectric vibrators 10. 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.

  The input device 20 is connected to the device main body 100 and includes a mouse, a keyboard, a button, a panel switch, a touch command screen, a foot switch, a trackball, and the like. The input device 20 receives various setting requests from the operator of the ultrasonic diagnostic apparatus 1 and transfers the received various setting requests to the apparatus main body 100. For example, the input device 20 receives a region of interest (ROI) setting request or a color gain setting request from an operator.

  The monitor 30 displays a GUI (Graphical User Interface) for an operator of the ultrasonic diagnostic apparatus 1 to input various setting requests using the input device 20, and displays an ultrasonic image generated in the apparatus main body 100. Or display. Specifically, the monitor 30 displays in-vivo morphological information and blood flow information as an image based on a video signal input from an image composition unit 160 described later.

  The apparatus main body 100 generates an ultrasonic image based on the reflected wave signal received by the ultrasonic probe 10. As illustrated in FIG. 1, the apparatus main body 100 includes an ultrasonic transmission unit 110, an ultrasonic reception unit 120, a B-mode processing unit 131, a Doppler processing unit 132, an image generation unit 140, and an image memory 150. An image composition unit 160, a control unit 170, a storage unit 180, and an interface unit 190.

  The ultrasonic transmission unit 110 includes a pulse generator 111, a transmission delay unit 112, and a pulsar 113, and supplies a drive signal to the ultrasonic probe 10. The pulse generator 111 repeatedly generates rate pulses for forming transmission ultrasonic waves at a predetermined rate frequency. In addition, the transmission delay unit 112 focuses the ultrasonic wave generated from the ultrasonic probe 10 into a beam shape, and the pulse generator 111 determines the delay time for each piezoelectric vibrator necessary for determining the transmission directivity. For each rate pulse that occurs. The pulser 113 applies a drive signal (drive pulse) to the ultrasonic probe 10 at a timing based on the rate pulse. Note that the transmission direction or the delay time for determining the transmission direction is stored in the storage unit 180, and the transmission delay unit 112 refers to the storage unit 180 and provides the delay time.

  The ultrasonic receiving unit 120 includes a preamplifier 121, an A / D (Analog / Digital) converter (not shown), a reception delay unit 122, and an adder 123, and performs various processes on the reflected wave signal received by the ultrasonic probe 10. To generate reflected wave data. The preamplifier 121 amplifies the reflected wave signal for each channel. An A / D converter (not shown) A / D converts the amplified reflected wave signal. The reception delay unit 122 gives a delay time necessary for determining the reception directivity. The adder 123 performs an addition process on the reflected wave signal processed by the reception delay unit 122 to generate reflected wave data. By the addition process of the adder 123, the reflection component from the direction corresponding to the reception directivity of the reflected wave signal is emphasized, and a comprehensive beam for ultrasonic transmission / reception is formed by the reception directivity and the transmission directivity. Similar to transmission, the reception direction or the delay time for determining the reception direction is stored in the storage unit 180, and the reception delay unit 122 refers to the storage unit 180 and gives the delay time.

  The B-mode processing unit 131 receives the reflected wave data from the ultrasonic receiving unit 120, performs logarithmic amplification, envelope detection processing, etc., and generates data (B-mode data) in which the signal intensity is expressed by brightness. To do.

  The Doppler processing unit 132 performs gain correction on the reflected wave data received from the ultrasonic wave receiving unit 120 with a predetermined color gain, and frequency-analyzes velocity information from the reflected wave data after gain correction. Then, the Doppler processing unit 132 extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect, and calculates blood flow information such as average velocity, variance, and power for multiple points. That is, the Doppler processing unit 132 operates as a blood flow information acquisition unit that performs gain correction (amplification) on the reception signal received by the ultrasonic probe 10 with color gain and obtains blood flow information based on the gain-corrected reception signal. It can be said that.

  The image generation unit 140 generates an ultrasonic image from the B-mode data generated by the B-mode processing unit 131 and the blood flow information generated by the Doppler processing unit 132, and the generated ultrasonic image is stored in an image memory 150 or Store in the storage unit 180.

  Specifically, the image generation unit 140 generates a B-mode image in which the signal intensity is expressed by brightness brightness from the B-mode data. Further, the image generation unit 140 generates, from the blood flow information, a color Doppler image that displays power components indicating blood flow velocity, dispersion, blood flow volume, and the like so as to be identifiable by color as a color image.

  The image generation unit 140 converts (scan converts) the scanning line signal sequence of the ultrasonic scan into a scanning line signal sequence of a video format typified by a television or the like, and an ultrasonic image (B-mode image) as a display image. Or color Doppler image).

  The image memory 150 is a memory that stores an ultrasonic image generated by the image generation unit 140 and an image generated by performing image processing on the ultrasonic image. For example, after diagnosis, the operator can call up an image recorded during the examination from the image memory 150 and can reproduce it as a still image or as a moving image using a plurality of images. . The image memory 150 stores an image luminance signal after passing through the ultrasonic receiving unit 120, other raw data, an image acquired via a network, and the like as necessary.

  The image composition unit 160 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 140. The composite image generated by the image composition unit 160 is displayed on the monitor 30.

  The control unit 170 is a control processor (CPU: Central Processing Unit) that realizes a function as an information processing apparatus (computer), and controls the entire processing in the ultrasonic diagnostic apparatus 1. Specifically, the control unit 170, based on various instructions and setting requests input from the operator via the input device 20, various programs read from the storage unit 180, and various setting information, Control the processing of the sound wave receiving unit 120, the B mode processing unit 131, the Doppler processing unit 132, the image generation unit 140, and the image composition unit 160, and display the ultrasonic image stored in the image memory 150 on the monitor 30. Or to control.

  The storage unit 180 stores various programs 181 for performing ultrasonic transmission / reception, image processing, and display processing, various data such as diagnostic information (for example, patient ID, doctor's findings, etc.), diagnostic protocol, and various setting information. . The various programs 181 may include a program in which a procedure for executing the same processing as that of the control unit 170 is described.

  The storage unit 180 is also used for storing an ultrasonic image stored in the image memory 150, as necessary. Various data stored in the storage unit 180 can be transferred to an external peripheral device via the interface unit 190.

  Further, the storage unit 180 includes a pixel rate storage unit 182 and a pixel number storage unit 183 that store the results counted by the control unit 170 described later. The pixel rate storage unit 182 and the pixel number storage unit 183 will be described in detail later.

  The interface unit 190 is an interface related to the input device 20, the operation panel, a new external storage device (not shown), and a network. Data such as an ultrasound image obtained by the ultrasound diagnostic apparatus 1 can be transferred by the interface unit 190 to another apparatus via a network.

  The ultrasonic transmission unit 110 and the ultrasonic reception unit 120 built in the apparatus main body 100 may be configured by hardware such as an integrated circuit, but are realized by a software modularized program. In some cases.

  The overall configuration of the ultrasonic diagnostic apparatus 1 according to this embodiment has been described above. Under such a configuration, when receiving an imaging start request for the subject P, the ultrasound diagnostic apparatus 1 displays a B-mode image or a color Doppler image of the subject P. Here, the color gain used when generating the color Doppler image is set by the operator. The color gain is a coefficient used when gain correction (amplification) is performed on the reception signal received by the ultrasonic probe. By correcting the gain of the received signal based on the color gain, blood flow information can be accurately acquired even when the received signal is small. Therefore, when the color gain is too small, blood flow information is not accurately displayed on the color Doppler image. On the other hand, when the color gain is too large, the noise is also amplified, so that the noise is displayed on the color Doppler image. The “noise” here includes, for example, a noise component generated in an internal circuit of the ultrasonic diagnostic apparatus 1 in addition to a noise component included in a signal transmitted and received by the ultrasonic probe 10.

  An example of a color Doppler image when the color gain is different will be described with reference to FIGS. 2 and 3 are diagrams illustrating an example of a color Doppler image. It is assumed that the color Doppler image shown in FIG. 2 is generated using an optimal color gain that accurately displays power as blood flow information. The color Doppler image shown in FIG. 3 is generated using a color gain larger than the color gain used when the color Doppler image shown in FIG. 2 is generated. The color Doppler images shown in FIGS. 2 and 3 are images in a predetermined region of interest R1 in the same part of the same subject P.

  In the color Doppler image illustrated in FIG. 2, there are pixels (pixels) with colors added to the regions A <b> 11 and A <b> 12, and blood flow information is accurately displayed. On the other hand, the color Doppler image shown in FIG. 3 is given a color as a whole, and noise is displayed as color information.

  In this way, even if the ultrasound diagnostic apparatus captures the same part of the same subject P, it generates color Doppler images with different color information if the operator sets different color gains. Is also possible. Furthermore, since the optimum value of the color gain varies depending on the part to be imaged, it is not easy for the operator to always set the optimum color gain. For this reason, it is difficult for an ultrasonic diagnostic apparatus to always use an optimal color gain, and as a result, it is considered difficult to always generate a color Doppler image in which blood flow information is accurately displayed.

  However, the ultrasonic diagnostic apparatus 1 according to the first embodiment enables the controller 170 to set an optimum color gain by performing various processes. Hereinafter, the processing performed by the control unit 170 in the first embodiment will be mainly described with reference to FIGS. 4 to 11.

  First, the flow of processing by the control unit 170 in the first embodiment will be described. When the control unit 170 in the first embodiment receives a request to start imaging of the subject P from the operator, first, the control unit 170 performs processing for setting an optimum color gain. Thereby, the control unit 170 enables generation of a color Doppler image in which noise or the like is not displayed and blood flow information or the like is accurately displayed.

  In addition, when the controller 170 receives a request for selecting an optimal color Doppler image from the operator after setting the optimal color gain, the control unit 170 selects a plurality of color Doppler images at the same shooting position from the plurality of color Doppler images. An optimal color Doppler image in which clutter components due to pulsation, body movement, etc. are not displayed in color is selected. Then, the control unit 170 displays an optimal color Doppler image on the monitor 30 or displays information that quantitatively indicates blood flow information included in the optimal color Doppler image on the monitor 30.

  Processing performed by the control unit 170 will be described in detail with reference to FIG. FIG. 4 is a block diagram illustrating a configuration example of the control unit 170 in the first embodiment. First, when receiving an imaging start request for the subject P from the operator, the control unit 170 controls the ultrasound transmission unit 110 to supply the ultrasound probe 10 with a drive signal.

  Then, the control unit 170 instructs the Doppler processing unit 132 to correct the gain of the reflected wave data input from the ultrasound receiving unit 120 with a plurality of different color gains at predetermined value intervals. Specifically, the control unit 170 notifies the Doppler processing unit 132 of the minimum value and the maximum value of the color gain, and the variation value, and the color gain is changed in order from the minimum value of the color gain. It is instructed to calculate a plurality of pieces of blood flow information from the same reflected wave data while varying by the amount.

  Thereby, the Doppler processing unit 132 in the first embodiment performs gain correction on the reflected wave data input from the ultrasonic receiving unit 120 with a plurality of different color gains at predetermined value intervals, for each color gain. Blood flow information is calculated.

  Specifically, the Doppler processing unit 132 stores the reflected wave data input from the ultrasound receiving unit 120 in a storage area such as the image memory 150 or the storage unit 180. Then, the Doppler processing unit 132 calculates blood flow information from the reflected wave data stored in the storage unit 180 using the minimum value of the color gain notified from the control unit 170. Subsequently, the Doppler processing unit 132 adds the fluctuation value to the minimum value of the color gain, and calculates blood flow information from the reflected wave data stored in the storage unit 180 using the color gain after the addition. In this way, the Doppler processing unit 132 calculates blood flow information while changing the color gain until the color gain reaches the maximum value notified from the control unit 170.

  The blood flow information is information indicating blood flow speed, dispersion, power, and the like. The Doppler processing unit 132 determines the speed, dispersion, power, etc. of the blood flow depending on whether the operator has selected a display mode of speed display, dispersion display, or power display, or a display mode that combines these information. Blood flow information is calculated.

  Then, the image generation unit 140 in the first embodiment performs a process of generating a color Doppler image from the blood flow information calculated by the Doppler processing unit 132 with respect to the blood flow information for each gain calculated by the Doppler processing unit 132. Do. In other words, the image generation unit 140 generates the same number of color Doppler images as the number of blood flow information from a plurality of blood flow information calculated using different color gains.

  Therefore, the image generation unit 140 generates a color Doppler image corresponding to the color gain for each color gain used by the Doppler processing unit 132 when generating blood flow information. The image generation unit 140 stores a plurality of color Doppler images generated in this way in the image memory 150. Note that the image generation unit 140 may store the color Doppler image in the storage unit 180, but in the first embodiment, the image generation unit 140 stores it in the image memory 150.

  Then, the controller 170 determines an optimum color gain by analyzing a plurality of color Doppler images generated by the image generation unit 140. Specifically, as illustrated in FIG. 4, the control unit 170 includes an ROI setting unit 171, an index calculation unit 172, and a gain selection unit 173, and processing performed by the index calculation unit 172 and the gain selection unit 173. To determine the optimum color gain.

  The ROI setting unit 171 sets a predetermined region of interest for a color Doppler image that is a color image generated by the image generation unit 140. Specifically, the ROI setting unit 171 receives the region of interest setting request received by the input device 20 via the interface unit 190, and sets the region of interest in the color Doppler image according to the received region of interest setting request. For example, when the operator performs an operation for setting a partial region of the color Doppler image as a region of interest, an index calculation unit 172 and a gain selection unit 173 described later target only the partial region as a processing target. Therefore, the processing load can be reduced.

  Based on the plurality of color Doppler images generated by the image generation unit 140, the index calculation unit 172 obtains an index value indicating the distribution of the color Doppler images. The index calculation unit 172 according to the first embodiment calculates, for each color Doppler image generated by the image generation unit 140, the number of pixels to which a color is assigned in the region of interest set by the ROI setting unit 171. Count as an index value. Hereinafter, a color pixel that is a pixel to which a color is assigned is referred to as a “color pixel”.

  The processing by the index calculation unit 172 will be specifically described. When the color Doppler image corresponding to each color gain is generated by the image generation unit 140, the index calculation unit 172 stores each color Doppler image in the image memory. It acquires sequentially from 150. Then, the index calculation unit 172 counts the number of color pixels included in the region of interest of the color Doppler image acquired from the image memory 150. Further, the index calculation unit 172 counts a “color pixel ratio” that is a ratio between the counted number of color pixels and the total number of pixels in the region of interest. For example, the index calculation unit 172 counts the color pixel ratio by dividing the counted number of color pixels by the total number of pixels in the region of interest.

  The index calculation unit 172 counts the color pixel ratio in the region of interest set at the same position in the plurality of color Doppler images stored in the image memory 150. Then, the index calculation unit 172 associates the color gain used when generating the color Doppler image with the color pixel rate of the color Doppler image, and stores the color gain in the pixel rate storage unit 182.

  Here, the pixel rate storage unit 182 will be described with reference to FIG. FIG. 5 is a diagram illustrating an example of the pixel rate storage unit 182. As illustrated in FIG. 5, the pixel rate storage unit 182 includes items such as “color gain” and “color pixel rate”.

  “Color gain” indicates a color gain used when generating a color Doppler image. Specifically, “color gain” indicates a color gain used by the Doppler processing unit 132 when blood flow information that is a generation source of the color Doppler image is calculated. The “color pixel rate” indicates the color pixel rate of a color Doppler image generated from blood flow information calculated by the corresponding color gain. In the first embodiment, the “color pixel rate” indicates the color pixel rate in the region of interest of the color Doppler image.

  For example, the pixel rate storage unit 182 illustrated in FIG. 5 indicates that the color pixel rate of the color Doppler image generated from the blood flow information calculated by the color gain “38” is “1%”. Further, for example, the pixel rate storage unit 182 illustrated in FIG. 5 indicates that the color pixel rate of the color Doppler image corresponding to the color gain “53” is “3%”.

  In the example illustrated in FIG. 5, the control unit 170 notifies the Doppler processing unit 132 of the minimum color gain value “38”, the maximum color gain value “62”, and the variation value “1”. It shows that. That is, in the example shown in FIG. 5, the Doppler processing unit 132 calculates blood flow information using the minimum color gain value “38” and changes the color gain until the maximum color gain value “62” is reached. Blood flow information is calculated while increasing the value by “1”.

  Returning to the description of FIG. 4, the gain selection unit 173 selects a display color gain based on comparison of index values obtained for a plurality of color gains. Specifically, the gain selection unit 173 according to the first embodiment uses the color pixel ratios of two color Doppler images corresponding to two adjacent color gains among the color pixel ratios counted by the index calculation unit 172. Are extracted respectively. Then, the gain selection unit 173 selects, as the optimum gain, the minimum value of the color gain group in which the extracted variation amount of the two color pixel rates is equal to or greater than a predetermined variation amount threshold value.

  More specifically, the gain selection unit 173 acquires two color pixel rates corresponding to two adjacent color gains from the pixel rate storage unit 182 updated by the index calculation unit 172, and acquires the acquired color pixel rates. It is determined whether or not the variation amount of the two color pixel ratios is equal to or greater than a predetermined variation amount threshold value. At this time, the gain selection unit 173 acquires two color pixel ratios corresponding to two adjacent color gains in order from the minimum value of the color gain. Then, when the variation amount of the color pixel rate is equal to or larger than the variation amount threshold, the gain selection unit 173 selects a small value as the optimum color gain from the two color gains.

  For example, assume that various data stored in the pixel rate storage unit 182 are in the state shown in FIG. Here, it is assumed that the fluctuation amount threshold is “5”. In such a case, the gain selection unit 173 first extracts two adjacent color gains “38” and “39” from the pixel rate storage unit 182. Then, the gain selection unit 173 changes the amount of variation “0 (=”) between the color pixel rate “1” corresponding to the extracted color gain “38” and the color pixel rate “1” corresponding to the color gain “39”. 1-1) "is calculated.

  Then, the gain selection unit 173 determines whether or not the calculated variation “0” is greater than or equal to the variation threshold “5”. Here, the gain selection unit 173 determines that the fluctuation amount “0” is smaller than the fluctuation amount threshold value “5”.

  Subsequently, the gain selection unit 173 extracts two adjacent color gains “39” and “40” from the pixel rate storage unit 182. Then, the gain selection unit 173 changes the variation “0 (= 1−1) between the color pixel rate“ 1 ”corresponding to the extracted color gain“ 39 ”and the color pixel rate“ 1 ”corresponding to the color gain“ 40 ”. 1) "is calculated. Then, the gain selection unit 173 determines whether or not the calculated variation “0” is greater than or equal to the variation threshold “5”.

  The gain selection unit 173 performs the above processing until the variation amount of the color pixel rate becomes equal to or greater than the variation amount threshold value. In the example illustrated in FIG. 5, when the gain selection unit 173 extracts two adjacent color gains “54” and “55”, the variation amount “5 (= 7-2)” of the color pixel rate is calculated. It is determined that the fluctuation amount threshold is “5” or more.

  In such a case, the gain selection unit 173 selects a small value as an optimum color gain from the two color gains whose variation amount of the color pixel rate is equal to or larger than the variation amount threshold value. In the case of the above example, the gain selection unit 173 determines that the variation amount of the color pixel rate is equal to or greater than the variation amount threshold when extracting the color gains “54” and “55”. "Is selected as the optimum color gain.

  Hereinafter, the reason why the optimum color gain can be selected by the processing by the gain selection unit 173 will be described. First, the ultrasonic diagnostic apparatus has a characteristic that as the color gain is increased, noise included in the color Doppler image rapidly increases with a predetermined color gain as a boundary. Such characteristics will be described using the example shown in FIG. FIG. 6 is a diagram illustrating a relationship example between the color gain and the color pixel rate. FIG. 6 is a graph showing the relationship between the color gain and the color pixel rate held by the pixel rate storage unit 182 illustrated in FIG.

  As in the example shown in FIG. 6, generally, when the color gain is small, the color pixel rate is low. On the other hand, when the color gain is large, the color pixel rate is high. Further, as the color gain is increased as in the example illustrated in FIG. 6, when the color gain exceeds a predetermined value, the color pixel ratio of the color Doppler image increases rapidly. This is because when the color gain is set to a predetermined value or more, the ratio of noise in the color Doppler image increases.

  In the example illustrated in FIG. 6, when the color gain is “38” to “54”, the variation amount of the color pixel rate is small and the color pixel rate is also low. That is, when the color gain is “38” to “54”, noise is hardly displayed on the color Doppler image. On the other hand, when the color gain becomes “55” or more, the color pixel rate increases rapidly. That is, when the color gain is “55” or more, the noise displayed in the color Doppler image increases rapidly. For this reason, when the color gain is changed, the color gain at which the color pixel ratio starts to increase suddenly appears as a color gain that hardly displays noise on the color Doppler image and noise appears on the color Doppler image. It can be said that this is a boundary with the color gain.

  Here, the optimum color gain indicates a gain that can generate a color Doppler image that contains as little noise as possible and that accurately displays blood flow information. As described with reference to FIG. 3, when the color gain is too large, noise is displayed in the color Doppler image, and when the color gain is too small, blood flow information is thinned out in the color Doppler image. Is not displayed. For this reason, the optimum color gain can be said to be the maximum value among the color gains in which noise is hardly displayed on the color Doppler image.

  Therefore, the gain selection unit 173 in the first embodiment specifies the color gain at which the color pixel rate starts to increase rapidly based on various data included in the pixel rate storage unit 182. Then, the gain selection unit 173 selects the maximum value as the optimum color gain among the color gains smaller than the specified color gain. In the example illustrated in FIG. 6, the gain selection unit 173 specifies the color gain “55” in which the color pixel rate starts to increase rapidly. Then, the gain selection unit 173 selects the maximum value “54” that is smaller than the color gain “55” as the optimum color gain.

  In this way, the index calculation unit 172 and the gain selection unit 173 select an optimal color gain. Then, the control unit 170 sets the color gain selected by the gain selection unit 173 in the Doppler processing unit 132. Specifically, the control unit 170 controls the Doppler processing unit 132 to use the color gain selected by the gain selection unit 173. For example, when the Doppler processing unit 132 uses the color gain stored in the storage unit 180, the control unit 170 stores the color gain selected by the gain selection unit 173 in the storage unit 180. Thereby, the Doppler processing unit 132 can calculate the blood flow information using the optimum color gain, and the image generation unit 140 contains almost no noise and the blood flow information is accurate. A color Doppler image to be displayed can be generated.

  The gain selection unit 173 may display the relationship between the color gain and the color pixel rate exemplified in FIG. 6 on the monitor 30 or may store them in the storage unit 180. Thereby, the ultrasound diagnostic apparatus 1 can make the operator confirm whether or not the color gain has been appropriately performed when the color Doppler image is later viewed by the operator.

  After setting the optimal color gain in this way, the ultrasound diagnostic apparatus 1 generates a color Doppler image using the optimal color gain. Here, when the control unit 170 in the first embodiment receives a request to display a color Doppler image of an optimal time phase from the operator, the control unit 170 of the plurality of color Doppler images generated at the same photographing position. A color Doppler image with few clutter components is selected from the images and displayed on the monitor 30. Further, the control unit 170 calculates quantification information quantitatively indicating blood flow information included in the optimum color Doppler image in accordance with a request from the operator, and displays the calculated quantification information on the monitor 30.

  Specifically, as illustrated in FIG. 4, the control unit 170 includes an image selection unit 174 and a quantification unit 175, and performs processing for selecting an optimal color Doppler image by processing by the image selection unit 174. And the process of calculating the quantification information by the process of the quantification unit 175 is performed.

  The image selection unit 174 selects a color Doppler image having the minimum or maximum number of color pixels as an optimal color Doppler image from the image memory 150 that stores a plurality of color Doppler images generated at the same shooting position. . The operator can perform a setting operation so as to select a color Doppler image having the minimum number of color pixels or the maximum number of color pixels, and the image selection unit 174 performs the operation. According to the setting operation by the user, it is determined whether the color Doppler image having the minimum or maximum number of color pixels is selected. Below, the process by the image selection part 174 is demonstrated concretely.

  First, since the ultrasonic diagnostic apparatus 1 is an apparatus that can display the blood flow information of the subject P on the monitor 30 in real time, the image generation unit 140 is in the same imaging position every time a predetermined time elapses. A color Doppler image is often generated. Therefore, the image memory 150 stores a plurality of color Doppler images at the same shooting position with different time phases (shooting times).

  Therefore, the image selection unit 174 acquires a plurality of color Doppler images having different time phases from the image memory 150 when receiving a request for displaying an optimal color Doppler image from the operator. Then, the image selection unit 174 counts the number of color pixels of the color Doppler image acquired from the image memory 150. The image selection unit 174 counts the number of color pixels for a plurality of color Doppler images at the same shooting position stored in the image memory 150. Then, the image selection unit 174 stores the image identification information for identifying the color Doppler image and the number of color pixels of the color Doppler image in the pixel number storage unit 183 in association with each other.

  Note that the image selection unit 174 may not count the number of color pixels for all of the plurality of color Doppler images at the same shooting position. For example, the image selection unit 174 may count the number of color pixels for a preset number of color Doppler images. For example, the image selection unit 174 may count the number of color pixels in the region of interest set by the ROI setting unit 171 in the color Doppler image.

  Here, the pixel number storage unit 183 will be described with reference to FIG. FIG. 7 is a diagram illustrating an example of the pixel number storage unit 183. As illustrated in FIG. 7, the pixel number storage unit 183 includes items such as “image identification information” and “color pixel number”.

  “Image identification information” indicates information for identifying a color Doppler image. Specifically, “image identification information” indicates information for identifying a color Doppler image stored in the image memory 150 at the same shooting position. “Number of color pixels” indicates the number of color pixels of the color Doppler image indicated by the corresponding image identification information.

  For example, the pixel number storage unit 183 illustrated in FIG. 7 indicates that the number of color pixels of the color Doppler image whose image identification information is “1” is “150”. For example, the pixel number storage unit 183 illustrated in FIG. 7 indicates that the number of color pixels of the color Doppler image whose image identification information is “2” is “165”.

  The image selection unit 174 that stores various data in the pixel number storage unit 183 in this way converts the color Doppler image having the minimum or maximum color pixel number stored in the pixel number storage unit 183 into an optimum color Select as Doppler image. To explain using the example shown in FIG. 7, the image selection unit 174 has the number of color pixels “150”, “165”, “143”, “151”, “149” stored in the pixel number storage unit 183. Among them, the color Doppler image indicated by the image identification information “3” corresponding to the minimum number of color pixels “143” is selected as the optimum color Doppler image. Alternatively, the image selection unit 174 selects the color Doppler image indicated by the image identification information “2” corresponding to the maximum number of color pixels “165” as the optimum color Doppler image.

  Then, the image selection unit 174 displays the selected optimal color Doppler image on the monitor 30. The image selection unit 174 may store the selected optimal color Doppler image in the image memory 150 or the storage unit 180 in accordance with an instruction from the operator.

  The reason why an optimal color Doppler image can be selected by the processing by the image selection unit 174 will be described below. As described above, the Doppler processing unit 132 and the image generation unit 140 generate a plurality of color Doppler images at the same shooting position using the optimum color gain selected by the gain selection unit 173. Therefore, in the plurality of color Doppler images generated in this way, noise is essentially not displayed and blood flow information and the like are accurately displayed. Further, since the color gain at the time of generation is the same, it is considered that all of the plurality of color Doppler images are the same.

  However, since the plurality of color Doppler images generated by the image generation unit 140 have different time phases, they indicate biological tissues in different time phases. Therefore, some of the plurality of color Doppler images may display clutter components resulting from pulsation, body movement, and the like as color information. In addition, since a change in blood flow occurs with time variation, all the plurality of color Doppler images are not necessarily the same. For this reason, it can be said that the number of color pixels of the color Doppler image generated using the optimum color gain varies due to clutter components caused by pulsation, body movement, and the like, and changes in blood flow.

  Here, when the living tissue of the imaging region is a living tissue whose blood flow time fluctuation is small, it can be said that the number of color pixels between a plurality of color Doppler images varies mainly due to clutter components. That is, the number of color pixels of a color Doppler image of a living tissue with a small blood flow time variation increases when a lot of clutter components are included, and does not increase when a clutter component is not included. In other words, it can be said that a color Doppler image having a smaller number of color pixels is a color Doppler image having less clutter components. Therefore, the image selection unit 174 according to the first embodiment has a plurality of images generated from the same imaging position by the image generation unit 140 when the biological tissue of the imaging region is a biological tissue in which the blood flow time fluctuation is small. Of the color Doppler images, the color Doppler image having the minimum number of color pixels can be selected as the optimum color Doppler image that does not substantially contain clutter components.

  In addition, for example, when the living tissue of the imaging region is a living tissue with a large time fluctuation of the blood flow, such as an arterial phase, it can be said that the number of color pixels between the plurality of color Doppler images greatly varies depending on the blood flow. When the blood flow is an arterial phase, it may be better to use the color Doppler image of the time phase showing the maximum blood flow as the optimum image because the blood flow is high. Therefore, the image selection unit 174 according to the first embodiment is configured to display a plurality of color Doppler images generated from the same imaging position by the image generation unit 140 when the blood flow of the biological tissue of the imaging region is large. Of these, the color Doppler image having the maximum number of color pixels may be selected as an optimal color Doppler image that does not substantially contain clutter components.

  As described above, the image selection unit 174 selects the color Doppler image having the minimum or maximum number of color pixels as the optimum image according to the setting operation by the operator. Note that the image selection unit 174 calculates the amount of variation in the number of color pixels between a plurality of color Doppler images generated at the same imaging position, and based on the calculated amount of variation, the blood flow rate in the living tissue of the imaging region. Time variation may be determined. The image selection unit 174 selects the color Doppler image having the minimum number of color pixels as the optimum color Doppler image when the time variation of the blood flow is small, and when the time variation of the blood flow is large. A color Doppler image having the maximum number of color pixels may be selected as the optimum color Doppler image.

  This will be described using the example shown in FIG. FIG. 8 is a diagram illustrating an example of the relationship between the passage of time and the number of color pixels. FIG. 8 is a graph showing the number of color pixels held by the pixel number storage unit 183 illustrated in FIG.

  As in the example shown in FIG. 8, even when a plurality of color Doppler images are generated with the optimum color gain at the same shooting position, the number of color pixels of the color Doppler image varies. Such a change in the number of color pixels can be said to be a change in the clutter component as described above. In the first embodiment, since a color Doppler image is generated with an optimum color gain, it can be said that a color Doppler image having a larger number of color pixels includes more clutter components. In other words, it can be said that a color Doppler image having a smaller number of color pixels does not include a clutter component. For this reason, in the example illustrated in FIG. 8, the image selection unit 174 selects a color Doppler image having the number of color pixels “143” as the optimum color Doppler image.

  Returning to the description of FIG. 4, the quantification unit 175 calculates quantification information that quantitatively indicates blood flow information included in the optimum color Doppler image selected by the image selection unit 174. Specifically, the quantification unit 175 is designated in advance with a region of interest (hereinafter referred to as “quantitative region of interest”) used when calculating the quantification information. Then, the quantification unit 175 receives the number of color pixels in the quantification region of interest of the optimum color Doppler image selected by the image selection unit 174 as quantification information in accordance with an instruction from the operator, and the quantification region of interest. The ratio with the total number of pixels is calculated. The quantification unit 175 displays the counted quantification information on the monitor 30 or stores it in the storage unit 180.

  Note that the quantification unit 175 may calculate the number of color pixels of the entire color Doppler image or the color pixel ratio of the entire color Doppler image as the quantification information. Further, the quantification unit 175 may calculate the sum of power values for the color pixels in the quantification region of interest of the color Doppler image as the quantification information. Further, the quantification unit 175 may calculate any one of the number of color pixels, the color pixel rate, and the total power value as the quantification information, or may calculate a plurality of pieces of information. .

  Thus, the quantification information calculated by the quantification unit 175 has high reliability. For example, when the color gain is set by the operator, there is a possibility that the color Doppler image includes noise. Therefore, the quantification information calculated from such a color Doppler image has low reliability. . Even if the color gain is set appropriately, the color Doppler image may contain a clutter component. Therefore, the quantification information calculated from such a color Doppler image is reliable. The nature is low. In other words, quantification information calculated from a color Doppler image containing noise and clutter components cannot be used as an index of blood flow information.

  On the other hand, since the color Doppler image selected by the image selection unit 174 does not include noise and clutter components, the quantification information calculated by the quantification unit 175 has high reliability. That is, the quantification unit 175 can provide the operator with quantification information that is an index of blood flow information.

  Next, a procedure of processing performed by the ultrasonic diagnostic apparatus 1 according to the first embodiment will be described with reference to FIG. FIG. 9 is a flowchart showing a processing procedure performed by the ultrasonic diagnostic apparatus 1 according to the first embodiment.

  As illustrated in FIG. 9, the ultrasonic diagnostic apparatus 1 according to the first embodiment determines whether or not an imaging start request has been received from the operator (step S <b> 101). Here, when the imaging start request is not accepted (No at Step S101), the ultrasonic diagnostic apparatus 1 enters a standby state.

  On the other hand, when the imaging start request is received (Yes at Step S101), the control unit 170 sets the counter i to “1” (Step S102). Then, under the control of the control unit 170, the Doppler processing unit 132 calculates blood flow information by performing gain correction on the reflected wave data input from the ultrasound receiving unit 120 with the i-th color gain ( Step S103). Here, the “i-th color gain” indicates a value obtained by adding the variation value “i−1” times to the minimum value of the color gain notified from the control unit 170 to the Doppler processing unit 132.

  Then, the image generation unit 140 generates a color Doppler image from the blood flow information calculated by the Doppler processing unit 132 (Step S104). Then, the index calculation unit 172 of the control unit 170 counts the color pixel ratio of the color Doppler image generated by the image generation unit 140 (step S105). For example, the index calculation unit 172 counts the number of color pixels in a predetermined region of interest of the color Doppler image, and divides the number of color pixels by the total number of pixels in the region of interest, thereby counting the color pixel rate.

  Then, the control unit 170 adds “1” to the counter i (step S106), and determines whether or not the i-th color gain is larger than the color gain maximum value notified to the Doppler processing unit 132 ( Step S107). If the i-th color gain is equal to or less than the color gain maximum value (No at step S107), the process returns to step S103.

  On the other hand, when the i-th color gain is larger than the color gain maximum value (Yes at Step S107), the gain selection unit 173 performs an optimum gain selection process (Step S108). The optimum gain selection process by the gain selection unit 173 will be described in detail with reference to FIG.

  Thereafter, the Doppler processing unit 132, the image generation unit 140, and the like generate a color Doppler image using the optimum color gain selected by the gain selection unit 173 (Step S109). Then, the control unit 170 determines whether or not an imaging end request has been received from the operator (step S110), and when the imaging end request has not been received (No at step S110), the process returns to step S109. On the other hand, the control part 170 complete | finishes a process, when the imaging | photography end request | requirement is received (step S110 affirmation).

  Next, the procedure of the optimum gain selection process shown in step S108 of FIG. 9 will be described using FIG. FIG. 10 is a flowchart illustrating an optimum gain selection processing procedure by the gain selection unit 173 in the first embodiment.

  As illustrated in FIG. 10, the gain selection unit 173 sets the counter i to “1” (step S201). Then, the gain selection unit 173 acquires, from the pixel rate storage unit 182, the color pixel rate corresponding to the i-th color gain and the color pixel rate corresponding to the (i + 1) -th color gain. A variation amount of the color pixel rate is calculated (step S202).

  Then, the gain selection unit 173 determines whether or not the variation amount of the color pixel rate is greater than or equal to the variation amount threshold (step S203). Here, when the variation amount of the color pixel rate is smaller than the variation amount threshold (No at Step S203), the gain selection unit 173 adds “1” to the counter i (Step S204), and returns to Step S202. .

  On the other hand, when the variation amount of the color pixel rate is equal to or larger than the variation amount threshold value (Yes in Step S203), the gain selection unit 173 selects the i-th color gain as the optimum color gain (Step S205).

  Although not shown in FIG. 10, the gain selection unit 173 can select an optimal color gain for the monitor 30 when there is no variation amount of the color pixel rate that is equal to or greater than the variation amount threshold. You may display that there was no. Alternatively, the gain selection unit 173 may select the maximum color gain as the optimum color gain among the plurality of color gains used by the Doppler processing unit 132.

  Next, the procedure of the optimum image selection process by the image selection unit 174 in the first embodiment will be described with reference to FIG. FIG. 11 is a flowchart illustrating an optimal image selection processing procedure by the image selection unit 174 according to the first embodiment.

  As illustrated in FIG. 11, when the image selection unit 174 receives a request to display an optimal color Doppler image from the operator (Yes in Step S301), the image selection unit 174 sets the counter j to “1” (Step S302). ).

  Then, the image selection unit 174 acquires the jth color Doppler image from the image memory 150 that stores a plurality of color Doppler images generated at the same shooting position, and counts the number of color pixels of the acquired color Doppler image. (Step S303). At this time, the image selection unit 174 stores the image identification information for identifying the color Doppler image in association with the number of color pixels of the color Doppler image in the pixel number storage unit 183.

  Then, the image selection unit 174 adds “1” to the counter j (step S304), and determines whether or not the counter j is larger than the threshold value M (step S305). Here, when the counter j is equal to or less than the threshold value M (No at Step S305), the image selection unit 174 returns to Step S303. Here, the “threshold value M” is the number of color Doppler images generated at the same shooting position stored in the image memory 150.

  Then, when the counter j is larger than the threshold value M (Yes at Step S305), the image selection unit 174 selects a color Doppler image in which the number of color pixels stored in the pixel number storage unit 183 is the minimum value or the maximum value. The optimal color Doppler image is selected (step S306). Then, the image selection unit 174 displays an optimal color Doppler image on the monitor 30 (step S307).

  After this, when the quantification information of the blood flow information is requested by the operator, the quantification unit 175 determines the number of color pixels, the color pixel rate, the sum of power values, etc. from the optimum color Doppler image. The quantification information is calculated, and the calculated quantification information is displayed on the monitor 30 or stored in the storage unit 180.

  As described above, according to the first embodiment, the Doppler processing unit 132 performs gain correction on the reception signals received by the ultrasound probe 10 at the same imaging position with different color gains, so that each color gain is obtained. In addition, blood flow information of the living tissue at the imaging position is calculated. Then, the image generation unit 140 performs a process of generating a color Doppler image with a different color according to the blood flow information from the blood flow information calculated by the Doppler processing unit 132 with respect to the blood flow information for each color gain. Do. Then, the index calculation unit 172 counts the number of color pixels for each color Doppler image generated by the image generation unit 140. Then, the gain selection unit 173 extracts the number of color pixels of two color Doppler images corresponding to two adjacent color gains from the number of color pixels counted by the index calculation unit 172, and extracts the extracted two The minimum value of the color gain group in which the variation amount of the number of color pixels is equal to or greater than the variation amount threshold is selected as the optimum color gain. Then, the control unit 170 controls the image generation unit 140 and the like so as to generate a color Doppler image using the reflected wave signal from the biological tissue gain-corrected by the color gain selected by the gain selection unit 173.

  Thereby, the ultrasound diagnostic apparatus 1 according to the first embodiment can set an optimum color gain. That is, the ultrasonic diagnostic apparatus 1 can generate a color Doppler image that contains as little noise as possible and that accurately displays blood flow information. Specifically, when the color gain is set by the operator, a color Doppler image that does not include noise and accurately displays the blood flow information is generated because the setting varies by the operator. Although not necessarily possible, the ultrasonic diagnostic apparatus 1 according to the first embodiment reliably generates a color Doppler image that does not include noise and accurately displays blood flow information. Can do.

  Furthermore, since the ultrasonic diagnostic apparatus 1 according to the first embodiment transmits an ultrasonic wave to the subject and sets an optimum color gain based on the reflected wave signal from the subject, the imaging target region and the imaging It is possible to set an optimum color gain for the time environment.

  In addition, according to the first embodiment, the image generation unit 140 that is controlled by the control unit 170 to perform image generation processing using an optimal color gain displays a plurality of color Doppler images at the same shooting position. Store in the memory 150. Then, the image selection unit 174 selects a color Doppler image having the minimum number of color pixels as an optimum color Doppler image from a plurality of color Doppler images generated at the same shooting position stored in the image memory 150. Then, the selected color Doppler image is displayed on the monitor 30.

  As a result, the ultrasonic diagnostic apparatus 1 according to the first embodiment can display a color Doppler image almost free of clutter components from among color Doppler images generated using an optimum color gain. it can. That is, the ultrasonic diagnostic apparatus 1 can display a color Doppler image that does not include noise and clutter components and accurately displays blood flow information.

  Further, according to the first embodiment, the quantification unit 175 uses the number of color pixels and the color pixels as quantification information that quantitatively indicates blood flow information included in the color Doppler image selected by the image selection unit 174. The rate, the sum of power values, etc. are calculated, and the calculated quantification information is displayed.

  As a result, the ultrasound diagnostic apparatus 1 according to the first embodiment calculates quantification information from a color Doppler image that does not include noise and clutter components and accurately displays blood flow information. Therefore, reliable quantification information can be provided to the operator.

  Various processes performed by the ultrasonic diagnostic apparatus 1 according to the first embodiment are not limited to the above example. Below, the modification of the various processes by the ultrasound diagnosing device 1 which concerns on 1st Embodiment is demonstrated.

  In the first embodiment, the ultrasound diagnostic apparatus 1 selects an optimal color gain, then selects an optimal color Doppler image, and further calculates quantification information from the optimal color Doppler image. Indicated. However, the ultrasonic diagnostic apparatus 1 may perform only the process of selecting the optimum color gain. That is, the ultrasonic diagnostic apparatus 1 may not include the image selection unit 174 and the quantification unit 175 illustrated in FIG. Even in such a case, the ultrasound diagnostic apparatus 1 can select an optimal color gain, and thus can generate a color Doppler image almost free of noise. Further, the ultrasonic diagnostic apparatus 1 may perform a process of selecting an optimal color gain and a process of selecting an optimal color Doppler image without performing a process of calculating quantification information, or an optimal color Doppler. A process of selecting an optimum color gain and a process of calculating quantification information may be performed without performing the process of selecting an image.

  In the first embodiment, as described with reference to FIG. 5, the index calculation unit 172 counts the color pixel ratio from a plurality of color Doppler images generated using different color gains. Indicated. However, the index calculation unit 172 may count the number of color pixels instead of the color pixel rate. In such a case, the gain selection unit 173 extracts the number of color pixels of two color Doppler images corresponding to two adjacent color gains from among the number of color pixels counted by the index calculation unit 172, and extracts them. The minimum value of the color gain group in which the variation amount of the two color pixels is equal to or greater than a predetermined variation amount threshold is selected as the optimum gain.

  In the first embodiment, an example is shown in which the index calculation unit 172 counts the color pixel ratio in a predetermined region of interest from a plurality of color Doppler images generated using different color gains. However, the index calculation unit 172 may count the ratio between the number of pixels of the entire color Doppler image and the number of color pixels of the entire color Doppler image as the color pixel rate.

  In the first embodiment, when selecting an optimum color gain, the Doppler processing unit 132 holds one reflected wave data input from the ultrasonic receiving unit 120 in the storage unit 180. In addition, an example is shown in which blood flow information is calculated for each color gain by correcting the gain of the reflected wave data with a plurality of different color gains. However, when the optimal color gain is selected, the control unit 170 may control the ultrasonic transmission unit 110 so as to generate a plurality of reflected wave data. In such a case, the Doppler processing unit 132 calculates blood flow information for each color gain by changing the color gain each time the reflected wave data is input from the ultrasound receiving unit 120.

  In the first embodiment, as described with reference to FIGS. 5, 6, and 10, the gain selection unit 173 extracts two adjacent color gains in order from the minimum color gain value. In the above example, it is determined whether or not the variation amount of the color pixel rate is equal to or greater than the variation amount threshold. That is, in the above description, the example in which the gain selection unit 173 determines the variation amount of the color pixel rate in the direction from the small value color gain to the large value color gain is shown. However, the gain selection unit 173 may determine the variation amount of the color pixel rate in the direction from the large value color gain to the small value color gain.

  In the first embodiment, as described with reference to FIGS. 5, 6, and 10, the gain selection unit 173 is optimal when the variation amount of the color pixel rate becomes equal to or larger than the variation amount threshold value. An example of selecting an appropriate color gain was shown. However, the gain selection unit 173 calculates the variation amount of the color pixel rate between two adjacent color gains for all two adjacent color gains, and the color whose variation amount of the color pixel rate is the maximum. You may determine the variation | change_quantity of a color pixel rate in the direction from a gain to the color gain of a small value.

  For example, assume that various data stored in the pixel rate storage unit 182 are in the state shown in FIG. In such a case, the gain selection unit 173 calculates the variation amount of the color pixel rate for all combinations of two adjacent color gains. In the example shown in FIG. 5, the variation amount of the color pixel rate corresponding to the color gains “59” and “60” is maximized. At this time, the gain selection unit 173 determines the variation amount of the color pixel rate in the direction from the color gain “59” to the color gain of a smaller value. Specifically, the gain selection unit 173 next extracts two adjacent color gains “58” and “59”, determines the variation amount of the color pixel rate, and the variation amount is determined based on the variation amount threshold value. If it is smaller, next, two adjacent color gains “57” and “58” are extracted, and the variation amount of the color pixel rate is determined.

  The gain selecting unit 173 can reduce the processing for comparing the variation amount and the variation amount threshold by performing the determination processing in this order, and as a result, the processing load can be reduced. Specifically, as shown in the example of FIG. 6, when the color gain is increased, if the color gain exceeds the optimum color gain, the color pixel ratio of the color Doppler image is initially abrupt. And then gradually increase. That is, it can be said that there is an optimum color gain in the vicinity of the color gain in which the variation amount of the color pixel rate is maximum. For this reason, the gain selection unit 173 determines the variation amount of the color pixel rate in the direction from the color gain with the largest variation amount of the color pixel rate to the color gain with a smaller value. The optimum color gain can be specified by the determination process.

  When the color gain obtained by subtracting a predetermined value from the color gain with the largest variation amount of the color pixel rate is found to be the optimum color gain, the gain selection unit 173 displays the color pixel rate. A color gain that is smaller by a predetermined value than the color gain for which the fluctuation amount of the color was maximum may be selected as the optimum color gain.

  In the first embodiment, the example in which the Doppler processing unit 132 calculates a plurality of blood flow information using a plurality of different color gains at predetermined value intervals when selecting an optimal color gain is shown. For example, FIG. 5 shows an example in which the Doppler processing unit 132 uses different color gains by “1”. However, the Doppler processing unit 132 may calculate a plurality of blood flow information using a color gain whose interval is not a constant value. For example, the Doppler processing unit 132 increases the color gain from “35” by “2”, increases by “1” when the color gain reaches “50”, and increases by “2” when the color gain reaches “63”. The blood flow information may be calculated by increasing it. In such a case, the gain selection unit 173 does not compare the variation amount of the color pixel rate between two adjacent color gains with the variation amount threshold value, but the variation amount of the color pixel rate with respect to the variation amount of the color gain. And the variation amount threshold value are compared. For example, the gain selection unit 173 compares the variation amount threshold with the result obtained by dividing the variation amount of the color pixel rate between two adjacent color gains by the variation amount of the color gain.

  Further, in the first embodiment, the gain selection unit 173 extracts two adjacent color gains in order from the minimum value of the color gain, and whether or not the variation amount of the color pixel rate is equal to or larger than the variation amount threshold value. An example of determining whether or not. However, the gain selection unit 173 may calculate the color pixel rate for a predetermined color gain range and determine whether or not the calculated variation amount of the color pixel rate is equal to or greater than the variation amount threshold value. This will be specifically described with reference to FIG. FIG. 12 is a diagram illustrating a relationship example between the color gain and the color pixel rate.

  In the example illustrated in FIG. 12, the color pixel ratio of the color Doppler image is large between the color gains “39” to “42”, and the color pixel ratio is between the color gains “42” to “55”. The variation amount of the color pixel ratio is small, and the variation amount of the color pixel ratio is large between the color gains “55” to “62”. For example, when the color Doppler image indicating the relationship between the color gain and the color pixel rate is generated at the color gains “39” to “41”, the blood flow information is not accurately displayed, and the color gain When generated at “42” to “55”, blood flow information is accurately displayed, and when generated at a color gain of “56” or higher, noise is considered to be displayed as a whole. As described above, the optimum color gain is the maximum value among the color gains in which noise is hardly displayed on the color Doppler image. Therefore, in the example shown in FIG. 12, the optimum color gain is “55”.

  By the way, in the example shown in FIG. 12, the gain selection unit 173 extracts two color gains adjacent in order from the minimum value of the color gain, and calculates the variation amount of the color pixel rate. There is a possibility that the variation amount of the color pixel rate at “39” and “40” is determined to be equal to or larger than the variation amount threshold value. Therefore, for example, the gain selection unit 173 extracts two adjacent color gains for the color gain range “45” to “60”, and determines whether or not the variation amount of the color pixel ratio is equal to or greater than the variation amount threshold value. It may be determined. Such a color gain range is stored in advance in the storage unit 180, and the gain selection unit 173 acquires the color gain range from the storage unit 180 when performing the process of selecting an optimum color gain. . Note that, for the color gain range, for example, different values for each part to be imaged may be stored in the storage unit 180.

  As described above, it can be said that there is an optimum color gain in the vicinity of the color gain where the variation amount of the color pixel rate is maximum. Therefore, even if the relationship between the color gain and the color pixel rate is the example shown in FIG. 12, the gain selection unit 173 changes the color gain from the maximum variation amount of the color pixel rate to the color gain of a small value. By determining the variation amount of the color pixel ratio in the direction of, the optimum color gain can be selected.

(Second Embodiment)
In the first embodiment, an example is shown in which the image selection unit 174 selects a color Doppler image having the minimum or maximum number of color pixels as an optimum color Doppler image from a plurality of color Doppler images at the same shooting position. It was. In the second embodiment, an example in which an optimal color Doppler image is selected without using information such as the number of color pixels counted from the color Doppler image will be described.

  First, the control part in 2nd Embodiment is demonstrated using FIG. FIG. 13 is a block diagram illustrating a configuration example of the control unit 270 according to the second embodiment. In the following, processing units having functions similar to those of the processing unit illustrated in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The configuration of the ultrasonic diagnostic apparatus according to the second embodiment is the same as the configuration example shown in FIG. However, as illustrated in FIG. 13, the ultrasonic diagnostic apparatus according to the second embodiment includes a Doppler processing unit 232 instead of the Doppler processing unit 132 illustrated in FIG. 1. In addition, the storage unit 180 in the second embodiment includes a cutoff frequency storage unit 284. As illustrated in FIG. 13, the control unit 270 in the second embodiment includes an image selection unit 274.

  The Doppler processing unit 232 includes a wall filter that can vary the cutoff frequency. Specifically, the Doppler processing unit 232 sets, on the wall filter, a filter characteristic that optimally separates the blood flow signal and the clutter signal included in the received signal based on the received signal received by the ultrasonic probe 10. (See US Pat. No. 6,224,557). That is, the Doppler processing unit 232 sets a high cutoff frequency when the clutter component included in the received signal is large, and sets a low cutoff frequency when the clutter component included in the received signal is small. The wall filter included in the Doppler processing unit 232 is, for example, an MTI (Moving Target Indicator) or a clutter removal filter.

  The image selection unit 274 has the lowest cut-off frequency of the wall filter used when the image generation unit 140 generates from a plurality of color Doppler images generated at the same shooting position stored in the image memory 150. The value color Doppler image is selected as the optimum color Doppler image.

  Specifically, every time a color Doppler image is generated by the image generation unit 140, the image selection unit 274 stores the cutoff frequency set in the Doppler processing unit 232 in the cutoff frequency storage unit 284. At this time, the image selection unit 274 stores the image identification information for identifying the color Doppler image generated by the image generation unit 140 and the cutoff frequency in the cutoff frequency storage unit 284 in association with each other. Note that the image generation unit 140 generates a color Doppler image from blood flow information gain-corrected with an optimal color gain, as in the first embodiment.

  Here, the cutoff frequency storage unit 284 will be described with reference to FIG. FIG. 14 is a diagram illustrating an example of the cutoff frequency storage unit 284. As illustrated in FIG. 14, the cutoff frequency storage unit 284 includes items such as “image identification information” and “cutoff frequency”.

  “Image identification information” indicates information for identifying a color Doppler image. “Cutoff frequency” indicates the cutoff frequency set in the wall filter of the Doppler processing unit 232 when the color Doppler image indicated by the corresponding image identification information is generated.

  For example, the cut-off frequency storage unit 284 illustrated in FIG. 14 generates a color Doppler image whose image identification information is “1” in a state where the cut-off frequency “f10” is set in the wall filter of the Doppler processing unit 232. It has been shown. Further, for example, the cutoff frequency storage unit 284 illustrated in FIG. 14 has a color Doppler image whose image identification information is “2” and a cutoff frequency “f20” is set in the wall filter of the Doppler processing unit 232. It is generated by.

  The image selection unit 274 that stores various data in the cut-off frequency storage unit 284 in this way stores the data in the cut-off frequency storage unit 284 when a request for displaying an optimal color Doppler image is received from the operator. The color Doppler image having the minimum cut-off frequency is selected as the optimum color Doppler image. For example, in the example shown in FIG. 14, it is assumed that the cut-off frequency “f10” is the minimum value among the cut-off frequencies “f10”, “f20”, “f30”, “f40”, and “f50”. . In such a case, the image selection unit 274 selects the color Doppler image indicated by the image identification information “1” corresponding to the cutoff frequency “f10” as the optimum color Doppler image.

  The reason why the optimum color Doppler image can be selected by the processing by the image selection unit 274 will be described below. As described in the first embodiment, the plurality of color Doppler images generated by the image generation unit 140 inherently display almost no noise and accurately display blood flow information and the like. Ingredients may be included. Here, the Doppler processing unit 232 sets a higher cutoff frequency as the number of clutter components included in the color Doppler image increases, and sets a lower cutoff frequency as the number of clutter components included in the color Doppler image decreases. In other words, the lower the cutoff frequency set by the Doppler processing unit 232 is, the fewer clutter components are included in the color Doppler image.

  For this reason, the image selection unit 274 in the second embodiment has the lowest cutoff frequency used at the time of image generation from a plurality of color Doppler images at the same shooting position generated by the image generation unit 140. Is selected as the optimum color Doppler image.

  Next, a procedure of processing performed by the ultrasonic diagnostic apparatus according to the second embodiment will be described with reference to FIG. FIG. 15 is a flowchart illustrating a processing procedure performed by the ultrasonic diagnostic apparatus according to the second embodiment. In the following, it is assumed that an optimum color gain is set by the gain selection unit 173.

  As illustrated in FIG. 15, the ultrasonic diagnostic apparatus according to the second embodiment determines whether an imaging start request has been received from the operator (step S <b> 401). Here, when the imaging start request is not accepted (No at Step S401), the ultrasonic diagnostic apparatus enters a standby state.

  On the other hand, when the imaging start request is accepted (Yes at Step S401), the Doppler processing unit 232 estimates an optimum filter characteristic and sets the estimated filter characteristic to the wall filter (Step S402). At this time, the image selection unit 274 stores the cutoff frequency set in the Doppler processing unit 232 in the cutoff frequency storage unit 284 (step S403).

  The Doppler processing unit 232 calculates blood flow information from the reflected wave data input from the ultrasound receiving unit 120 using a wall filter in which optimum filter characteristics are set. Then, the image generation unit 140 generates a color Doppler image from the blood flow information calculated by the Doppler processing unit 232 (Step S404). At this time, the image selection unit 274 stores the image identification information of the color Doppler image generated by the image generation unit 140 in association with the cutoff frequency in the cutoff frequency storage unit 284.

  Then, the control unit 270 determines whether or not an imaging end request has been received from the operator (step S405). If no imaging end request has been received (No at step S405), the process returns to step S402.

  On the other hand, when a photographing end request is received (Yes at Step S405), the image selecting unit 274 determines whether a request for displaying an optimal color Doppler image is received from the operator (Step S406). Here, if the image selection unit 274 does not receive a request to display an optimum color Doppler image from the operator (No at Step S406), the image selection unit 274 ends the process.

  On the other hand, when the image selection unit 274 receives a request to display an optimal color Doppler image from the operator (Yes in step S406), the cut-off frequency stored in the cut-off frequency storage unit 284 is minimum. The value color Doppler image is selected as the optimum color Doppler image (step S407). Then, the image selection unit 274 displays an optimal color Doppler image on the monitor 30 (step S408).

  As described above, according to the second embodiment, the Doppler processing unit 232 sets the filter characteristics of the wall filter based on the reception signal received by the ultrasonic probe 10, and then determines a predetermined value from the reception signal. Is removed. Then, the image generation unit 140 controlled so that the image generation unit 140 performs image generation processing using the optimal color gain by the control unit 170 is the same as the blood flow information generated by the Doppler processing unit 232. A plurality of color Doppler images at the photographing position are generated, and the generated color Doppler images are stored in the image memory 150. Then, the cutoff frequency of the wall filter used when the image selection unit 274 generates the image generation unit 140 from a plurality of color Doppler images generated at the same shooting position stored in the image memory 150. The color Doppler image having the lowest value is selected as the optimum color Doppler image, and the selected color Doppler image is displayed on the monitor 30.

  As a result, the ultrasonic diagnostic apparatus according to the second embodiment can select an optimal color Doppler image without counting the number of color pixels and the color pixel rate of the color Doppler image, which increases the processing load. And a color Doppler image substantially free of clutter components can be displayed. That is, the ultrasonic diagnostic apparatus according to the second embodiment prevents an increase in processing load, and includes a color Doppler image that does not include noise and clutter components and accurately displays blood flow information. Can be displayed.

(Third embodiment)
In the first embodiment, an example in which an optimal color gain is selected by transmitting an ultrasonic wave to the subject P and generating a color Doppler image using a reflected wave signal from the subject P has been described. In the third embodiment, an example in which an optimum color gain is selected without transmitting ultrasonic waves to the subject P is shown.

  First, the control part in 3rd Embodiment is demonstrated using FIG. FIG. 16 is a block diagram illustrating a configuration example of a control unit in the third embodiment. In the following, processing units having functions similar to those of the processing unit illustrated in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The configuration of the ultrasonic diagnostic apparatus according to the third embodiment is the same as the configuration example shown in FIG. However, as illustrated in FIG. 16, the storage unit 180 in the third embodiment includes an optimum color gain storage unit 384. As illustrated in FIG. 16, the control unit 370 in the third embodiment includes an ROI setting unit 371, an index calculation unit 372, and a gain selection unit 373.

  When receiving an imaging start request from the operator, the ROI setting unit 371 stops the processing by the ultrasonic transmission unit 110 and changes the set position of the region of interest at regular time intervals. That is, the ROI setting unit 371 changes the set position of the region of interest after stopping the transmission function by the ultrasonic diagnostic apparatus and starting the reception function.

  For this reason, the ultrasonic reception unit 120, the Doppler processing unit 132, and the image generation unit 140 do not receive the reflected wave signal from the subject P, but receive the noise signal and the like generated around the ultrasonic diagnostic apparatus. A color Doppler image is generated from a noise signal or the like.

  Then, the Doppler processing unit 132 in the third embodiment performs gain correction on the data input from the ultrasound receiving unit 120 with a plurality of different color gains at predetermined value intervals, as in the first embodiment. Blood flow information is calculated for each color gain. Then, the image generation unit 140 generates a color Doppler image from the blood flow information calculated by the Doppler processing unit 132.

  In addition, the index calculation unit 372 counts the number of color pixels for each color Doppler image generated by the image generation unit 140. At this time, the index calculation unit 372 counts the number of color pixels in the region of interest set by the ROI setting unit 371. Then, the index calculation unit 372 counts a color pixel rate that is a ratio between the counted number of color pixels and the total number of pixels in the region of interest.

  In addition, the gain selection unit 373 in the third embodiment selects an optimum color gain for each region of interest based on the color pixel ratio counted by the index calculation unit 372. The relationship between the color pixel ratio and the color gain counted by the index calculation unit 372 draws a waveform similar to the example shown in FIG. Therefore, the gain selection unit 373 can select an optimum color gain by performing the same processing as in the first embodiment.

  In other words, the index calculation unit 372 and the gain selection unit 373 in the third embodiment perform the same processing as in the first embodiment for each region of interest set by the ROI setting unit 371, so that each region of interest. Select the optimal color gain. Then, the gain selection unit 373 associates the region of interest with the optimum color gain, and stores them in the optimum color gain storage unit 384.

  Here, the optimum color gain storage unit 384 will be described with reference to FIG. FIG. 17 is a diagram illustrating an example of the optimum color gain storage unit 384. As illustrated in FIG. 17, the optimum color gain storage unit 384 includes items such as “region of interest” and “optimum color gain”.

  The “region of interest” indicates a region of interest set by the ROI setting unit 371. “Optimum color gain” indicates the optimum color gain selected by the gain selection unit 373. For example, the optimum color gain storage unit 384 illustrated in FIG. 17 indicates that the optimum color gain is “G11” when the region of interest is set to “R11”. For example, the optimum color gain storage unit 384 illustrated in FIG. 17 indicates that the optimum color gain is “G12” when the region of interest is set to “R12”.

  In this way, after selecting an optimal color gain for each region of interest, the ultrasonic diagnostic apparatus according to the third embodiment generates a color Doppler image in accordance with an instruction from the operator. At this time, the Doppler processing unit 132 acquires the color gain corresponding to the region of interest set by the operator from the optimum color gain storage unit 384, and calculates blood flow information using the acquired color gain.

  Next, the procedure of optimum gain selection processing by the ultrasonic diagnostic apparatus according to the third embodiment will be described with reference to FIG. FIG. 18 is a flowchart illustrating an optimal gain selection processing procedure performed by the ultrasonic diagnostic apparatus according to the third embodiment.

  As illustrated in FIG. 18, the ultrasonic diagnostic apparatus according to the third embodiment determines whether an imaging start request has been received from the operator (step S501). Here, when the imaging start request is not accepted (No at step S501), the ultrasonic diagnostic apparatus enters a standby state.

  On the other hand, when the imaging start request is received (Yes at Step S501), the control unit 370 stops the processing by the ultrasonic transmission unit 110 (Step S502) and sets a region of interest (Step S503). Then, the ROI setting unit 371 sets the counter i to “1” (step S504).

  Then, under the control of the control unit 370, the Doppler processing unit 132 calculates blood flow information by correcting the gain of the reflected wave data input from the ultrasound receiving unit 120 using the i-th color gain ( Step S505). Then, the image generation unit 140 generates a color Doppler image from the blood flow information calculated by the Doppler processing unit 132 (Step S506). Then, the index calculation unit 372 counts the color pixel ratio in the region of interest set in step S503 among the color Doppler images generated by the image generation unit 140 (step S507).

  Then, the control unit 370 adds “1” to the counter i (step S508), and determines whether or not the i-th color gain is larger than the color gain maximum value notified to the Doppler processing unit 132 ( Step S509). If the i-th color gain is equal to or smaller than the color gain maximum value (No at step S509), the process returns to step S505.

  On the other hand, when the i-th color gain is larger than the color gain maximum value (Yes at Step S509), the gain selection unit 373 performs an optimum gain selection process (Step S510). The optimum gain selection process by the gain selection unit 373 is the same as the optimum gain selection process shown in FIG. At this time, the gain selection unit 373 associates the information for identifying the region of interest set in step S503 with the optimum color gain selected in the optimum gain selection process, and stores the information in the optimum color gain storage unit 384.

  Then, the control unit 370 determines whether or not the optimum gain selection process has been performed for all the regions of interest that are the targets of the optimum gain selection process (step S511). If the optimal gain selection processing has not been performed for all the regions of interest (No at Step S511), the process returns to Step S503, and the ROI setting unit 371 sets an unprocessed region of interest (Step S503).

  On the other hand, if the optimum gain selection process has been performed for all the regions of interest (Yes at step S511), the process ends. Thereafter, when generating a color Doppler image, the ultrasound diagnostic apparatus acquires the color gain corresponding to the region of interest set by the operator from the optimum color gain storage unit 384 and acquires the color gain. Blood flow information is calculated using the color gain.

  As described above, according to the third embodiment, the ROI setting unit 371 changes the region of interest at regular time intervals after stopping the processing by the ultrasonic transmission unit 110. Then, the image generation unit 140 generates a color Doppler image for each region of interest that is changed by the ROI setting unit 371. Then, the index calculation unit 372 counts the number of color pixels for each color Doppler image generated by the image generation unit 140. Then, the gain selection unit 373 generates two color Doppler images corresponding to two adjacent color gains among the number of color pixels counted by the index calculation unit 372 for each region of interest that is changed by the ROI setting unit 371. The number of color pixels is extracted, and the minimum value of the color gain group in which the fluctuation amount of the two extracted color pixels is equal to or larger than the fluctuation amount threshold is selected as the optimum color gain.

  Thereby, the ultrasonic diagnostic apparatus according to the third embodiment can set an optimum color gain. In particular, since the ultrasonic diagnostic apparatus according to the third embodiment does not perform transmission processing and performs only reception processing to set an optimum color gain, system noise generated in an internal circuit of the ultrasonic diagnostic apparatus is not generated. A color gain that is not displayed in the color Doppler image can be set.

  In addition, since the ultrasonic diagnostic apparatus according to the third embodiment sets an optimal color gain for each region of interest, noise is hardly included in each region of interest, and blood flow information is accurately displayed. A color Doppler image can be generated. For example, when the ROI setting unit 371 changes the region of interest for each depth direction from the ultrasonic probe 10 to the inside of the subject, the ultrasonic diagnostic apparatus according to the third embodiment performs each depth direction. The optimum color gain can be set.

  In the third embodiment, an example in which an optimal color gain is estimated for each region of interest by setting a plurality of regions of interest or changing the region of interest while the transmission process is stopped has been described. . However, the ultrasonic diagnostic apparatus according to the third embodiment can estimate one optimal color gain for all the regions of interest without changing the regions of interest while the transmission process is stopped. Good. That is, when a plurality of regions of interest are set, one representative optimum color gain to be applied to the entire color image region may be set based on the processing results in all the set regions of interest. As a typical color gain setting method, the average value of the color gain obtained in each region of interest may be adopted, or the minimum or maximum value of the color gains obtained in each region may be adopted. Good. Furthermore, the number of regions of interest is not limited to a plurality, and may be one.

(Fourth embodiment)
In the first embodiment, an example has been described in which the index calculation unit 172 counts the color pixel ratio as an index value indicating the distribution of the color Doppler image. In the fourth embodiment, an example in which information other than the color pixel rate is calculated as an index value indicating the distribution of the color Doppler image will be described.

  First, the control part in 4th Embodiment is demonstrated using FIG. FIG. 19 is a block diagram illustrating a configuration example of the control unit 470 according to the fourth embodiment. In the following, processing units having functions similar to those of the processing unit illustrated in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The configuration of the ultrasonic diagnostic apparatus according to the fourth embodiment is the same as the configuration example shown in FIG. However, as illustrated in FIG. 19, the storage unit 180 in the fourth embodiment includes an analysis result storage unit 482. As illustrated in FIG. 19, the control unit 470 in the fourth embodiment includes an index calculation unit 472 and a gain selection unit 473.

  The index calculation unit 472 analyzes, for each color Doppler image generated by the image generation unit 140, the color pixels assigned to the color Doppler image, thereby indicating the distribution shape of the color pixels included in the color Doppler image as an index value. Asking.

  Specifically, when a color Doppler image corresponding to each color gain is generated by the image generation unit 140, the index calculation unit 472 acquires each of the color Doppler images from the image memory 150 in order, and the color Doppler image. The distribution shape of the color pixels included in the region of interest is calculated. Then, the index calculation unit 472 associates the color gain used when generating the color Doppler image with the distribution shape information indicating the distribution shape of the color pixels in the color Doppler image, and stores the association in the analysis result storage unit 482. .

  The gain selection unit 473 selects a display color gain based on the comparison of the distribution shapes of the color pixels calculated as index values by the index calculation unit 472. Specifically, the gain selection unit 473 extracts and extracts two pieces of distribution shape information corresponding to two adjacent color gains from the distribution shape information stored in the analysis result storage unit 482. When the fluctuation amount of the two pieces of distribution shape information is greater than or equal to a predetermined fluctuation amount threshold value, a smaller value is selected as the optimum color gain from the two color gains.

  Explaining with an example, the gain selection unit 473 is similar to the gain selection unit 173 in the first embodiment, in order of two distribution shapes corresponding to two adjacent color gains in order from the minimum value of the color gain. Get information. Then, the gain selection unit 473 obtains the similarity between the two distribution shapes, for example, by performing pattern analysis on both distribution shapes indicated by the distribution shape information. Then, when the similarity is equal to or greater than the variation amount threshold, the gain selection unit 473 selects a small value as the optimum color gain from the two color gains.

  Here, the reason why the optimum color gain can be selected by the processing by the gain selection unit 473 will be described. As described in the first embodiment, when the color gain is increased, the ultrasonic diagnostic apparatus has a characteristic that noise included in the color Doppler image rapidly increases with a predetermined color gain as a boundary. is there. That is, generally, when the color gain is small, the color pixel rate is low, and when the color gain is large, the color pixel rate is high. For this reason, when the color gain is increased, there is no significant difference in the distribution shape of the color pixels in the color Doppler image generated using each color gain until the predetermined value is reached, but the color gain is the predetermined value. When the noise is increased and the noise increases rapidly, it can be said that the distribution shape of the color pixels in the color Doppler image changes greatly.

  For example, the relationship between the color gain and the color pixel rate is the example shown in FIG. In this case, when the color gain is “38” to “54”, the color pixel ratio does not fluctuate greatly, so that any color Doppler image is a color Doppler image as illustrated in FIG. On the other hand, when the color gain is “55” or more, the color pixel ratio fluctuates greatly. Therefore, as the color gain increases, the color Doppler image illustrated in FIG. 2 is changed to the color Doppler image illustrated in FIG. It changes rapidly. When comparing the color Doppler images illustrated in FIGS. 2 and 3, it can be seen that there is a large difference in the distribution shape of the color pixels. Therefore, the gain selection unit 473 can select the maximum value among the color gains in which noise is hardly displayed on the color Doppler image by selecting the color gain “55”.

  Next, a procedure of processing performed by the ultrasonic diagnostic apparatus according to the fourth embodiment will be described with reference to FIG. FIG. 20 is a flowchart illustrating a processing procedure performed by the ultrasonic diagnostic apparatus according to the fourth embodiment. Note that the processing procedure in steps S605 and S608 out of the processing procedure shown in FIG. 20 is different from the processing procedure shown in FIG. 10, and therefore, the processing procedure in steps S605 and S608 will be mainly described below.

  As shown in FIG. 20, the image generation unit 140 according to the fourth embodiment generates a color Doppler image from the blood flow information calculated by the Doppler processing unit 132 (Step S604). Then, the index calculation unit 472 of the control unit 470 analyzes the color Doppler image generated by the image generation unit 140 to obtain the distribution shape of the color pixels included in the color Doppler image (Step S605). The index calculation unit 472 stores the distribution shape information indicating the distribution shape in the analysis result storage unit 482 in association with the color gain.

  Then, the control unit 470 adds “1” to the counter i (step S606), and determines whether or not the i-th color gain is larger than the color gain maximum value notified to the Doppler processing unit 132 ( Step S607). Then, the gain selection unit 473 performs optimum gain selection processing (step S608). The optimum gain selection processing by the gain selection unit 473 will be described in detail with reference to FIG.

  Thereafter, the Doppler processing unit 132, the image generation unit 140, and the like generate a color Doppler image using the optimum color gain selected by the gain selection unit 473 (Step S609).

  Next, the procedure of the optimum gain selection process shown in step S608 of FIG. 20 will be described using FIG. FIG. 21 is a flowchart illustrating an optimal gain selection processing procedure by the gain selection unit 473 according to the fourth embodiment.

  As illustrated in FIG. 21, the gain selection unit 473 sets the counter i to “1” (step S701). Then, the gain selection unit 473 acquires the distribution shape information corresponding to the i-th color gain and the distribution shape information corresponding to the (i + 1) -th color gain from the analysis result storage unit 482, and acquires the acquired two pieces. The distribution shape information is compared (step S702). For example, the gain selection unit 473 calculates the similarity between the two distribution shapes as the variation amount of the distribution shapes.

  Then, the gain selection unit 473 determines whether or not the variation amount of the distribution shape is equal to or larger than the variation amount threshold value (step S703). Here, when the variation amount of the distribution shape is smaller than the variation amount threshold (No at Step S703), the gain selection unit 473 adds “1” to the counter i (Step S704), and returns to Step S702.

  On the other hand, when the variation amount of the distribution shape is greater than or equal to the variation amount threshold value (Yes in step S703), the gain selection unit 473 selects the i-th color gain as the optimum color gain (step S705).

  As described above, according to the fourth embodiment, the index calculation unit 472 obtains an index value by analyzing the distribution shape of the color pixels assigned to the color Doppler image, and the gain selection unit 473 includes a plurality of values. Based on the comparison of the index values analyzed for the color gain, the optimum color gain is selected. Thereby, the ultrasonic diagnostic apparatus according to the fourth embodiment can set an optimum color gain.

  As another means of the fourth embodiment using pattern analysis, an index value corresponding to the shape may be calculated by analyzing the shape of the distribution. In this case, the index value calculation unit 472 controls to assign a high index value when it is determined that the distribution shape is close to the shape derived from noise. Specifically, the index value of the distribution shape is obtained by, for example, storing a score table that associates the shape of the color pixel distribution and the index value in the index calculation unit 472 in advance and reading the corresponding score table. In the score table, for example, a low index value is used for shapes in which color pixels are distributed on a straight line, and a high index value is used for shapes in which color pixels are distributed in a circle. A higher index value is assigned to the shape in which the pixels are distributed. Thereby, a high index value can be assigned to a color pixel derived from noise by using a phenomenon that color pixels derived from noise appear at random.

  In the first to fourth embodiments, blood flow information has been described as an example of information to be displayed on a color Doppler image. However, the ultrasonic diagnostic apparatuses according to the first to fourth embodiments are described. The present invention can also be applied when information other than blood flow information is displayed on a color Doppler image. For example, the ultrasonic diagnostic apparatuses according to the first to fourth embodiments can also be applied to the case where the movement information of each tissue is displayed on the color Doppler image by the tissue Doppler method.

  In the first to fourth embodiments, the example in which the Doppler processing units 132 and 232 perform gain correction on the data input from the ultrasonic reception unit 120 using the color gain has been described. The received signal received by the ultrasonic probe 10 may be gain-corrected using the color gain. In such a case, the preamplifier 121 in the first to fourth embodiments uses the optimum color gain selected by the gain selection unit 173 or the like.

  In the first, second, and fourth embodiments, the number of color pixels in the region of interest set in the color Doppler image is counted, or the distribution shape of the color pixels in the region of interest is analyzed. showed that. However, the index calculation unit 172 may count the number of color pixels in the entire color Doppler image, and the index calculation unit 472 may analyze the distribution shape of the color pixels in the entire color Doppler image.

  Further, the index calculation unit 372 in the third embodiment does not count the number of color pixels, but analyzes the distribution shape of the color pixels in the color Doppler image in the same manner as the index calculation unit 472 in the fourth embodiment. May be. Then, the gain selection unit 373 may select an optimum color gain based on the variation in the distribution shape, similarly to the gain selection unit 473 in the fourth embodiment.

  The processing by the ultrasonic diagnostic apparatus according to the first to fourth embodiments may be performed by the ultrasonic diagnostic apparatus and the image processing apparatus. This point will be described with reference to FIG. FIG. 22 is a diagram illustrating a configuration example of an image processing system. The image processing system illustrated in FIG. 22 includes an ultrasonic diagnostic apparatus 1, an image processing apparatus 2 such as a workstation, and a terminal apparatus 3.

  The ultrasonic diagnostic apparatus 1 and the image processing apparatus 2 perform processing by the ultrasonic diagnostic apparatus described in the first to fourth embodiments. For example, the ultrasonic diagnostic apparatus 1 includes the ultrasonic probe 10, the ultrasonic transmission unit 110, the ultrasonic reception unit 120, the B-mode processing unit 131, and the Doppler processing unit 132 illustrated in FIG. Includes the image generation unit 140, the image memory 150, the image synthesis unit 160, the control unit 170, the storage unit 180, and the interface unit 190. The processing by the ultrasonic diagnostic apparatus described in the fourth embodiment is performed. Further, for example, the ultrasonic diagnostic apparatus 1 includes the ultrasonic probe 10, the ultrasonic transmission unit 110, and the ultrasonic reception unit 120 illustrated in FIG. 1, and the image processing apparatus 2 includes the B-mode processing unit 131 and the Doppler. By including the processing unit 132, the image generation unit 140, the image memory 150, the image synthesis unit 160, the control unit 170, the storage unit 180, and the interface unit 190, the ultrasonic diagnostic apparatus 1 and the image processing apparatus 2 can be Processing by the ultrasonic diagnostic apparatus described in the fourth embodiment is performed. In any example, both the ultrasonic diagnostic apparatus 1 and the image processing apparatus 2 have a CPU and an interface unit. As described above, the processing by the ultrasonic diagnostic apparatus described in the first to fourth embodiments may be performed by the ultrasonic diagnostic apparatus 1 and the image processing apparatus 2. In the example illustrated in FIG. 22, the terminal device 3 is an information processing device such as a PC (Personal computer) used by a user such as a doctor, and a color Doppler image or the like stored in the image processing device 2. And control display on a predetermined display unit.

  As described above, according to the first to fourth embodiments, an optimum color gain can be set.

  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 diagnostic apparatus 100 Apparatus main body 110 Ultrasonic transmission unit 120 Ultrasonic reception unit 131 B mode processing unit 132, 232 Doppler processing unit 140 Image generation unit 150 Image memory 160 Image composition part 170, 270, 370, 470 Control part 171 , 371 ROI setting unit 172, 372, 472 Index calculation unit 173, 373, 473 Gain selection unit 174, 274 Image selection unit 175 Quantification unit 180 Delay time is storage unit 181 Various programs 182 Pixel rate storage unit 183 Pixel number storage unit 190 Interface unit 284 Cut-off frequency storage unit 384 Optimal color gain storage unit

Claims (13)

A movement information acquisition unit that obtains movement information by correcting the reception signal received by the ultrasonic probe with a gain;
An image generation unit that performs a process of generating a color image to which color pixels are assigned based on the movement information;
An index calculation unit for obtaining an index value indicating a distribution of the color pixels based on a plurality of color images generated by the image generation unit;
A gain selection unit for selecting a display gain based on a comparison of the index values obtained for a plurality of gains;
A control unit that controls the image generation unit to generate a color image to which color pixels are allocated based on the display gain and movement information obtained from the received signal;
An ultrasonic diagnostic apparatus comprising: The index calculation unit
Count the number of color pixels assigned to the color image as the index value,
The gain selection unit
Selecting a display gain based on a comparison of index values counted for a plurality of the gains;
The ultrasonic diagnostic apparatus according to claim 1. The index calculation unit
Obtaining the index value by analyzing the distribution shape of the color pixels assigned to the color image;
The gain selection unit
Selecting a display gain based on a comparison of index values analyzed for a plurality of gains;
The ultrasonic diagnostic apparatus according to claim 1. The index calculation unit
The ratio of the color pixels in the allocated range of the color pixels is calculated as the index value,
The gain selection unit
A display gain is selected based on a comparison of index values obtained for a plurality of gains.
The ultrasonic diagnostic apparatus according to claim 1. A region of interest setting unit for setting a region of interest that is a range to which the color pixel is allocated in the color image;
The gain selection unit
The ultrasonic diagnostic apparatus according to claim 1, wherein a display gain is selected based on a comparison of the index values within the region of interest. An image storage unit that stores a plurality of color images at the same photographing position generated by the image generation unit under the control of the control unit;
The controller is
From a plurality of color images generated at the same shooting position stored in the image storage unit, a color image having the minimum or maximum number of color pixels is selected as an optimal color image, and the selected color image is selected. Having an image selection unit for displaying on a predetermined display unit;
The ultrasonic diagnostic apparatus according to claim 1. Based on the received signal received by the ultrasonic probe, after setting the frequency band to be removed, a filter unit for removing the frequency band from the received signal;
An image storage unit that stores a plurality of color images at the same photographing position generated by the image generation unit from the reflected wave signal transmitted through the filter unit under the control of the control unit;
The controller is
The upper limit frequency of the removal target frequency band of the filter unit used when generated by the image generation unit from a plurality of color images generated at the same shooting position stored in the image storage unit is the lowest value A color image is selected as an optimal color image, and the selected color image is displayed on a predetermined display unit.
The ultrasonic diagnostic apparatus according to claim 1. The controller is
Controlling the image generation unit to generate a color image after stopping the ultrasonic wave transmission processing by the ultrasonic probe,
The ultrasonic diagnostic apparatus according to claim 1. The gain selection unit
The index values of the two color images corresponding to the two gains are extracted in order from the smallest gain among the plurality of gains, and the fluctuation amount of the two extracted index values is equal to or greater than a predetermined fluctuation amount threshold value. when it becomes to select the smaller of the two gain as optimal gain,
The ultrasonic diagnostic apparatus according to claim 1. The gain selection unit
For each two adjacent gains among the plurality of gains, a fluctuation amount between index values corresponding to the two gains is calculated, and a gain that approximates the two gains having the maximum calculated fluctuation amount to select as the optimal gain,
The ultrasonic diagnostic apparatus according to claim 1.   A quantification unit that calculates a ratio between the number of color pixels of the color image and the number of pixels of the color image as quantification information quantitatively indicating movement information included in the color image selected by the image selection unit; The ultrasonic diagnostic apparatus according to claim 6 or 7, further comprising: The movement information is obtained by correcting the reception signal received by the ultrasonic probe with the gain,
Controlling an image generation unit that performs a process of generating a color image to which color pixels are assigned based on the movement information;
Obtaining an index value indicating the distribution of the color pixels based on a plurality of color images;
Based on the comparison of the index values obtained for a plurality of gains, a display gain is selected,
Controlling the image generation unit to generate a color image to which color pixels are assigned based on movement information obtained from the display gain and the received signal;
An image generation method. An index value indicating the distribution of the color pixels is obtained from a plurality of color images to which the color pixels are assigned by the image generation unit based on movement information obtained by correcting the reception signal received by the ultrasonic probe with a gain. The desired index calculator,
A gain selection unit for selecting a display gain based on a comparison of the index values obtained for a plurality of gains;
A control unit that controls the image generation unit to generate a color image to which color pixels are allocated based on the display gain and movement information obtained from the received signal;
An image processing apparatus comprising: