JP7469877B2 - Ultrasound diagnostic device, medical image processing device, and medical image processing program - Google Patents

Description

The embodiments disclosed in this specification and the drawings relate to an ultrasound diagnostic device, a medical image processing device, and a medical image processing program.

Some ultrasound diagnostic devices are capable of capturing images in color Doppler mode (CFM (Color Flow Mapping) mode), which displays ultrasonic Doppler images in color. In CFM mode, an ultrasonic Doppler image calculated based on blood flow signals (reflected signals from blood) is superimposed in color on a B-mode image depicting the morphology of the subject. The color ultrasonic Doppler image shows blood flow dynamics information calculated based on Doppler signals whose frequency has been Doppler shifted by reflection from moving objects within the subject. The Doppler signal is calculated from the phase shift amount (Doppler shift amount) per unit time of the blood flow signal obtained by scanning the same location at a specified time interval. The ultrasonic Doppler image makes it possible to visualize blood flow.

However, when an ultrasound Doppler image is superimposed on a B-mode image, a phenomenon called blooming or overpainting may occur, in which the blood flow depicted in the ultrasound Doppler image extends beyond the diameter of the blood vessel depicted in the B-mode image. Blooming can occur due to the beating of the heart depending on the area being observed. In addition, in the lower limbs, blooming can also occur due to the milking operation, in which the legs are massaged with the hands. When blooming occurs, blood flow is depicted in areas where there is no blood flow, making it extremely difficult to grasp the position of blood vessels and blood flow dynamics in the ultrasound Doppler image, which impedes diagnosis.

JP 2014-161554 A

One of the problems that the embodiments disclosed in this specification and the drawings attempt to solve is to reduce blooming in color Doppler mode. However, the problems that the embodiments disclosed in this specification and the drawings attempt to solve are not limited to the above problem. Problems that correspond to the effects of each configuration shown in the embodiments described below can also be positioned as other problems.

The ultrasound diagnostic device according to the embodiment includes a determination unit and an image generation unit. The determination unit determines at least one of a power threshold and a variance threshold for displaying ultrasound Doppler image data relating to the subject's blood flow velocity on the display unit based on at least one of the power and variance of the subject's blood flow signal. The image generation unit generates ultrasound Doppler image data relating to the subject's blood flow velocity based on the threshold and displays the data on the display unit.

FIG. 1 is a block diagram showing an example of the configuration of an ultrasound diagnostic apparatus according to an embodiment. FIG. 2 is an explanatory diagram showing an example of the configuration of a Doppler processing circuit according to the present embodiment. FIG. 1 is an explanatory diagram showing an example of a conventional color Doppler image. FIG. 4A is an explanatory diagram showing an example of a power value image, and FIG. 4B is an explanatory diagram showing an example of a histogram of power values. FIG. 2 is an explanatory diagram showing an example of an ultrasonic Doppler image generated by the image generating circuit according to the embodiment. 13 is an explanation showing an example of how a user's instruction regarding a threshold is accepted. FIG. 13 is an explanatory diagram showing an example in which a histogram and information indicating a threshold value are displayed simultaneously. FIG. 2A is a diagram for explaining divided regions when a region of interest is divided into three in the depth direction, and FIG. 2B is a diagram for explaining divided regions when a region of interest is divided into three in the scanning direction. FIG. 1A is an explanatory diagram showing an example of thresholds determined based on a histogram for each of three divided regions aligned in the depth direction, and FIG. 1B is an explanatory diagram showing an example of multiple curves in which the relationship between depth and threshold is predefined. 11A and 11B are diagrams for explaining an example of a case in which a correction value for a threshold is determined in accordance with a measured value of an attenuation value. 11A and 11B are diagrams for explaining averaging processing of provisional thresholds according to the position of a region of interest. FIG. 13 is an explanatory diagram showing an example of a table for determining a threshold value based on both power and variance.

Below, embodiments of an ultrasound diagnostic device, a medical image processing device, and a medical image processing program will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an example of the configuration of an ultrasound diagnostic device 10 according to an embodiment. The ultrasound diagnostic device 10 can be used by being connected to an ultrasound probe 20, an input interface 21, and a display 22. Note that the ultrasound diagnostic device 10 may include at least one of the ultrasound probe 20, the input interface 21, and the display 22.

As shown in FIG. 1, the ultrasound diagnostic device 10 has a transmission/reception circuit 11, a B-mode processing circuit 12, a Doppler processing circuit 13, an image generation circuit 14, an image memory 15, a storage circuit 16, a network connection circuit 17, and a control circuit 18.

The transmission/reception circuit 11 has a transmission circuit and a reception circuit. The transmission/reception circuit 11 is controlled by the control circuit 18 to control the transmission directivity and reception directivity in transmitting and receiving ultrasound. Note that while FIG. 1 shows an example in which the transmission/reception circuit 11 is provided in the ultrasound diagnostic device 10, the transmission/reception circuit 11 may be provided in the ultrasound probe 20, or may be provided in both the ultrasound diagnostic device 10 and the ultrasound probe 20.

The transmission circuit has a pulse generator, a transmission delay circuit, a pulsar circuit, etc., and supplies a drive signal to the ultrasonic transducer. The pulse generator repeatedly generates rate pulses to form a transmission ultrasonic wave at a predetermined rate frequency. The transmission delay circuit provides each rate pulse generated by the pulse generator with a delay time for each piezoelectric transducer required to focus the ultrasonic waves generated from the ultrasonic transducer into a beam and determine the transmission directivity. In addition, the pulsar circuit applies a drive pulse to the ultrasonic transducer at a timing based on the rate pulse. The transmission delay circuit changes the delay time provided to each rate pulse to arbitrarily adjust the transmission direction of the ultrasonic beam transmitted from the piezoelectric transducer surface.

The receiving circuit has an amplifier circuit, an A/D converter, an adder, etc., and receives the echo signal received by the ultrasonic transducer and performs various processes on this echo signal to generate echo data. The amplifier circuit amplifies the echo signal for each channel and performs gain correction processing. The A/D converter A/D converts the gain-corrected echo signal and gives the digital data the delay time required to determine the reception directivity. The adder performs addition processing of the echo signal processed by the A/D converter to generate echo data. The addition processing of the adder emphasizes the reflected components from the direction corresponding to the reception directivity of the echo signal.

The B-mode processing circuit 12 receives the echo data from the receiving circuit and performs logarithmic amplification, envelope detection processing, etc. to generate data (B-mode data) in which the signal strength is expressed as luminance brightness.

The Doppler processing circuit 13 performs frequency analysis of velocity information from the blood flow signal of the echo data received from the receiving circuit, extracts blood flow, tissue, and contrast agent echo components due to the Doppler effect, and generates data (Doppler data) that extracts blood flow dynamics information such as average velocity, variance, and power for multiple points. In addition, the Doppler processing circuit 13 determines at least one of the power threshold and variance threshold when displaying ultrasonic Doppler image data related to the subject's blood flow velocity on the display 22 based on at least one of the power of the blood flow signal and the variance of the velocity component. The configuration of the Doppler processing circuit 13 will be described in detail later with reference to FIG. 2.

The image generation circuit 14 generates ultrasound image data based on the echo signals received by the ultrasound probe 20 and displays the data on the display 22. For example, the image generation circuit 14 generates two-dimensional B-mode image data that represents the intensity of the reflected waves as brightness from the B-mode data received from the B-mode processing circuit 12. The image generation circuit 14 also generates ultrasound Doppler image data related to the blood flow velocity of the subject as an image showing hemodynamic information based on the Doppler data and threshold value received from the Doppler processing circuit 13. The image generation circuit 14 is an example of an image generation unit.

The image memory 15 is a memory that stores image data such as B-mode image data and ultrasonic Doppler image data generated by the image generation circuit 14. The image memory 15 may also store data generated by the B-mode processing circuit 12 and the Doppler processing circuit 13.

The memory circuit 16 has a configuration including a processor-readable recording medium, such as a magnetic or optical recording medium or a semiconductor memory. Some or all of the programs and data in the storage medium of the memory circuit 16 may be downloaded by communication via an electronic network, or may be provided to the memory circuit 16 via a portable storage medium such as an optical disk. Some or all of the information stored in the memory circuit 16 may be distributed and stored in at least one storage medium, such as an external storage circuit or a storage circuit (not shown) of the ultrasound probe 20, or may be copied and stored.

The network connection circuit 17 implements various information communication protocols according to the form of the network 100. The network connection circuit 17 connects the ultrasound diagnostic device 10 to other electrical devices according to these various protocols. This connection can be an electrical connection via an electronic network. Here, the electronic network refers to any information communication network that uses electrical communication technology, and includes wireless/wired LANs such as hospital backbone LANs (Local Area Networks) and Internet networks, as well as telephone communication line networks, optical fiber communication networks, cable communication networks, and satellite communication networks.

The control circuit 18 provides the function of overall control of the ultrasound diagnostic device 10.

The ultrasound probe 20 is detachably connected to the ultrasound diagnostic device 10 via a cable. The ultrasound probe 20 may also be wirelessly connected to the ultrasound diagnostic device 10.

The ultrasonic probe 20 may be a two-dimensional array probe in which multiple ultrasonic transducers are arranged in the scan direction (azimuth direction) and multiple elements are also arranged in the lens direction (elevation direction). Examples of this type of two-dimensional array probe that may be used include a 1.5D array probe, a 1.75D array probe, and a 2D array probe.

The ultrasound probe 20 may be configured to acquire volume data. In this case, the subject may be scanned three-dimensionally using the ultrasound probe 20, which is a two-dimensional array probe, or the subject may be scanned two-dimensionally using the ultrasound probe 20, which is a one-dimensional ultrasound probe in which multiple piezoelectric transducers are arranged in a row, or the subject may be scanned three-dimensionally by rotating these multiple ultrasound transducers, or the multiple piezoelectric transducers of the one-dimensional ultrasound probe may be mechanically oscillated.

When the ultrasound probe 20 is capable of acquiring volume data, the user can select either a two-dimensional display mode (2D mode) in which any of a number of two-dimensional ultrasound images is displayed as a real-time video or as a still image, or a four-dimensional display mode (4D mode) in which a three-dimensional ultrasound image acquired in real time is displayed as a video.

The input interface 21 is realized by general input devices such as a trackball, a switch, a button, a mouse, a keyboard, a touchpad that performs input operations by touching the operation surface, a non-contact input circuit using an optical sensor, and a voice input circuit, and outputs an operation input signal corresponding to a user's operation to the control circuit 18. The input interface 21 may be configured as an operation panel. In this case, the operation panel functions as a touch command screen and has, for example, a display, a touch input circuit provided near the display, and hard keys.

The display 22 is composed of a general display output device such as a liquid crystal display or an OLED (Organic Light Emitting Diode) display, and displays various information according to the control of the control circuit 18.

In addition, if the ultrasound diagnostic device 10 is a tablet or smartphone type ultrasound diagnostic device 10, the input interface 21 and the display 22 may be integrated to form a touch panel.

The ultrasound diagnostic device 10 may also be connected to the medical image processing device 30 and the image server 40 via the network 100 so that data can be transmitted and received between them.

Figure 2 is an explanatory diagram showing an example of the configuration of the Doppler processing circuitry 13 according to this embodiment. The Doppler processing circuitry 13 is a processor that reads out and executes a medical image processing program stored in the memory circuitry 16, thereby working with the image generation circuitry 14 to execute processing for reducing blooming in color Doppler mode.

As shown in FIG. 2, the processor of the Doppler processing circuitry 13 realizes a wall filter function 31, an autocorrelation function 32, a histogram generation function 33, a threshold determination function 34, a correction function 35, and a blank function 36. Each of these functions is stored in the memory circuitry 16 in the form of a program. Note that some or all of these functions may be realized by hardware logic without using a processor.

The wall filter function 31 removes clutter components that originate from the movement of organs, etc. other than blood flow, from the Doppler signal generated based on the blood flow signal.

The autocorrelation function 32 obtains Doppler data (data extracted from multiple points on hemodynamic information such as blood flow velocity, power, and dispersion) based on the Doppler signal.

The histogram generation function 33 generates a histogram of the power of the blood flow signal in the region of interest. In this embodiment, the "region of interest" refers to the region to be processed for histogram generation. The region of interest is defined within a set region for obtaining the blood flow signal, and may be the same region as the set region. The region of interest is set to include both regions where blood flow exists and regions where blood flow does not exist.

The histogram generation function 33 may also generate a histogram of the variance component of blood flow instead of or in addition to the power histogram.

The threshold determination function 34 determines at least one of the power threshold and the variance threshold when displaying ultrasonic Doppler image data related to the subject's blood flow velocity on the display 22 based on the histogram generated by the histogram generation function 33. The threshold determination function 34 may also determine the threshold as a value associated with both the power and the variance so that data with lower power and data with higher variance are subject to deletion in the blanking process.

This threshold is used in blanking processing by the blanking function 36. The threshold determination function 34 can determine the power threshold according to, for example, the mode, median, mean, probability density function, etc. of the power histogram.

The correction function 35 corrects the threshold value according to user instructions, changes in the threshold value between frames, etc. The threshold value determination function 34 and the correction function 35 are examples of a determination unit.

The blanking function 36 performs blanking processing to delete data for each observation point in the region of interest based on the threshold determined by the determination unit. For example, when a power threshold is received from the threshold determination function 34, the blanking function 36 deletes data whose power value is equal to or less than the threshold. Also, when a variance threshold is received from the threshold determination function 34, the blanking function 36 deletes data whose variance value is equal to or greater than the threshold.

In addition, when the threshold value determination function 34 receives a threshold value associated with both power and variance, the blanking function 36 performs blanking processing based on both the power and variance values, as described below with reference to FIG. 12.

The image generation circuit 14 generates ultrasound Doppler image data relating to the subject's blood flow velocity based on the Doppler data after blank processing based on a threshold value by the Doppler processing circuit 13, and displays the data on the display 22. The image generation circuit 14 may also store the generated image data in the image server 40.

The Doppler processing circuit 13 and the image generation circuit 14 may be provided in a medical image processing device 30 connected to the ultrasound diagnostic device 10. In this case, the ultrasound diagnostic device 10 provides a blood flow signal to the medical image processing device 30, and the Doppler processing circuit 13 and the image generation circuit 14 of the medical image processing device 30 determine at least one of a power threshold and a variance threshold based on at least one of the power and variance of the blood flow signal in real time or in post-processing, and generate ultrasound Doppler image data related to the blood flow velocity of the subject based on this threshold and display it on the display 22 or the display of the medical image processing device 30. This medical image processing device 30 is an example of an image processing device.

Below, we will explain an example of using a power threshold with reference to Figures 3 to 11.

Figure 3 is an explanatory diagram showing an example of a conventional color Doppler image. Figure 3 shows an example of a color Doppler image of the carotid artery. Conventional blanking processing uses a preset fixed value as the power threshold. For this reason, blooming as shown in Figure 3 occurs due to the effects of cardiac pulsation, milking, etc.

Therefore, in this embodiment, the Doppler processing circuit 13 and image generation circuit 14 adaptively determine the blanking threshold for each display frame based on the blood flow signal.

Figure 4(a) is an explanatory diagram showing an example of a power value image, and (b) is an explanatory diagram showing an example of a histogram of power values. Also, Figure 5 is an explanatory diagram showing an example of an ultrasonic Doppler image generated by the image generation circuit 14 according to this embodiment. Note that Figures 3, 4(a) and 5 show examples in which the region of interest coincides with the entire image shown.

The histogram of power values changes from frame to frame due to the effects of pulsation, etc. For this reason, the mode also changes from frame to frame. As shown in Figure 4(b), the peak of the histogram is at a point where the power value is small, and the peak is thought to be composed of data from observation points where there is no blood flow. For this reason, if the threshold value of the power value for blanking processing is set to a fixed value, blooming may occur over a wide area if the power value of the histogram peak exceeds the fixed threshold.

On the other hand, the threshold determination function 34 determines the power threshold according to the mode, median, mean, probability density function, etc. of the power histogram in the region of interest so that data of pixels with a weak blood flow signal and no blood flow can be deleted while retaining data of pixels with a strong blood flow signal and where blood flow is present. As is clear from a comparison of the color Doppler images of the carotid artery shown in Figures 3 and 5, by adaptively determining the power threshold in this way based on the power histogram, it is possible to prevent the relationship between the threshold and the histogram peak from being unintentionally reversed, and blooming in color Doppler mode can be significantly reduced.

Figure 6 is an explanatory diagram showing an example of how a user's instruction regarding the threshold is accepted. As shown in Figure 6, the correction function 35 may display a blank adjustment acceptance image 51 on the display 22 or the display of the input interface 21 functioning as a touch command screen, and change the relationship between the threshold and the histogram peak in response to a user's instruction. In the example shown in Figure 6, the user selects the strength of the blanking process via the blank adjustment acceptance image 51. The correction function 35 corrects the threshold to be higher so that the more data is erased, the stronger the strength of the selected blanking process. In this case, the user can obtain the desired blooming mitigation processing result simply by selecting the strength of the blanking process.

The number of bins in a histogram such as that shown in FIG. 6 may not be fixed, but may be changeable based on user instructions. For example, when the number of bins is increased, the power range assigned to each bin becomes narrower, allowing for more precise threshold setting. Also, the number of bins may be reduced, and the power range assigned to each bin may be wider.

The number of bins may not only be changed based on user instructions, but may also be set based on the size of the region of interest, which is the set region for obtaining a blood flow signal or the region to be processed for generating a histogram, the examination region (examination site), and the magnitude of temporal or spatial fluctuation of the blood flow signal (velocity, power, or variance). For example, the number of bins may be increased as the size of the region of interest increases. Also, the number of bins may be increased as the fluctuation of the blood flow signal (e.g., standard deviation) increases.

Figure 7 is an explanatory diagram showing an example of simultaneously displaying a histogram and information indicating a threshold value. By displaying an image 52 including both a histogram and information indicating a threshold value, for example, for each frame or discretely for each predetermined number of frames, the user can intuitively and easily grasp the relationship between the histogram and the threshold value. Furthermore, the correction function 35 may directly accept, via this image 52, an instruction from the user to specify a threshold value or an instruction to specify the number of bins or the width of each bin in the histogram on the histogram.

Figure 8 (a) is a diagram for explaining the divided regions when the region of interest is divided into three in the depth direction, and (b) is a diagram for explaining the divided regions when the region of interest is divided into three in the scanning direction.

For example, as the position becomes deeper, the blood flow signal attenuates and weakens. Also, the depth and number of blood vessels may vary depending on the position. For this reason, the threshold determination function 34 may divide the region of interest into multiple regions and create a histogram for each divided region to determine the threshold. For example, in the example shown in Figures 8 (a) and (b), the threshold determination function 34 may create a histogram for each of the divided regions 61, 62, and 63 to determine the threshold. In this case, a threshold appropriate for the position of the divided region can be determined, so blooming can be more appropriately reduced.

In addition, the necessity for dividing the region of interest and the method of division (number of divisions and division direction) may be determined according to at least one of the strength of the echo signal, the speed, power, and variance of the blood flow signal. For example, when the variance of the power of the region of interest or divided region is greater than a predetermined upper limit, it is determined that a useful histogram cannot be obtained and the region is divided to reduce the variance within each region. On the other hand, when the variance is less than a predetermined lower limit, there is a possibility that only regions with blood flow or only regions without blood flow remain, so the range of the region is expanded by combining adjacent regions into one region, for example, and the number of divisions is reduced.

In addition, whether or not to divide the region of interest and how to divide it may be determined depending on the observation site. Information on the observation site may be obtained from the examination order information, or may be provided by the user via the input interface 21. For example, for an observation site that extends in the depth direction, it is advisable to divide the region of interest in the depth direction.

In addition, if information on the direction in which blood vessels run within the region of interest can be obtained, it is advisable to divide the region of interest in the direction in which the blood vessels run. By dividing the region of interest in the direction in which the blood vessels run, it is easy to include both regions where blood flow exists and regions where blood flow does not exist in each divided region.

Figure 9 (a) is an explanatory diagram showing an example of thresholds determined based on a histogram for each of three divided regions aligned in the depth direction, and (b) is an explanatory diagram showing an example of multiple curves that predefine the relationship between depth and threshold.

In general, due to the effect of attenuation, the deeper the position, the smaller the histogram peak. For this reason, it is considered that the deeper the position, the smaller the threshold value. Therefore, the correction function 35 may correct the threshold value determined for each divided region based on the distribution of the threshold value determined for each divided region. Specifically, it is preferable to compare a correction table (see FIG. 9(b)) that predefines the relationship between depth and threshold value with the threshold value determined for each divided region (see FIG. 9(a)), select the closest curve, and correct the threshold value. In this case, the correction function 35 may correct each of the threshold values for the three divided regions in the region of interest and use the three discrete threshold values after correction, or may continuously determine the threshold value for each data position based on the selected curve, regardless of the number of divided regions.

Figure 10 is a diagram for explaining an example of determining a threshold correction value according to a measured value of attenuation. If the ultrasound diagnostic device 10 has a function for measuring the amount of ultrasonic attenuation, the correction function 35 may correct the threshold based on the measured attenuation value of the echo signal or blood flow signal or its depth-direction integral value (see FIG. 10, left). In this case, the correction function 35 corrects the threshold so that the larger the attenuation value, the smaller the threshold value. Also, if the ultrasound diagnostic device 10 has a function for measuring the S/N ratio, the correction function 35 may correct the threshold based on the S/N curve. In this case, the correction function 35 corrects so that the lower the S/N ratio and the smaller the signal ratio, for example, the smaller the threshold value.

The threshold determination function 34 may also create and determine a histogram or threshold based on information from multiple frames. For example, a histogram may be created based on data from multiple frames, and a threshold for multiple frames may be determined based on this one histogram. A histogram may also be created for each frame to obtain a provisional threshold, and a threshold for multiple frames may be determined by averaging the provisional thresholds for multiple adjacent frames. Averaging the thresholds for multiple frames makes the change in threshold more gradual, improving smoothness when ultrasound Doppler images are displayed continuously for each frame.

The threshold determination function 34 may also determine whether to average the provisional thresholds or use the provisional thresholds as is, depending on the change between the provisional thresholds of multiple frames. In the case of averaging, the threshold determination function 34 may further determine the number of adjacent frames to average, depending on the change.

For example, consider the case where a provisional threshold is calculated based on the histogram for each of two adjacent frames. In this case, if the two provisional thresholds are not very different, it is decided that they can be averaged.

On the other hand, if the difference between the two provisional thresholds is greater than a specified value, it is believed that there has been a change in the blood flow conditions between frames. For this reason, it is advisable to decide to use the provisional threshold as is, especially when you want to increase the strength of the blanking process to reduce blooming as much as possible. If the difference between the provisional thresholds is large, averaging will lower the threshold of the frame corresponding to the high provisional threshold due to the influence of the low provisional threshold, and it may not be possible to remove blooming in the frame corresponding to the high provisional threshold.

The threshold determination function 34 may also determine whether to average the provisional thresholds or use them as is depending on whether the change in the threshold is positive (i.e., an increase) or negative (i.e., a decrease). For example, if it is desired to increase the strength of the blanking process to minimize blooming and the change is negative, averaging can be performed to correct the current low provisional threshold to a higher value due to the influence of the past high provisional threshold. On the other hand, if it is desired to increase the strength of the blanking process to minimize blooming and the change is positive, conversely, not averaging can be performed to eliminate the influence of the past low provisional threshold.

Figure 11 is a diagram to explain the averaging process of the provisional threshold according to the position of the region of interest.

The threshold determination function 34 determines whether to average the provisional thresholds or use the provisional thresholds as is depending on the position of the observed area or region of interest, and may also determine the number of adjacent frames to average if averaging is performed.

For example, the averaging process may be different depending on the position of the region of interest. For example, the provisional threshold value is not averaged for a region of interest 71 set at a shallow position, whereas for a region of interest 72 set at a deep position, the blood flow signal is small and the S/N ratio is small, so the provisional threshold values of more frames (e.g., three adjacent frames) are averaged compared to a shallow position.

Also, the averaging process may be different depending on the observation area, for example, averaging two adjacent frames when the observation area is the abdomen, averaging three adjacent frames when the observation area is the carotid artery, and no averaging when the observation area is the adult heart.

The above describes an example of using a power threshold with reference to Figures 3-11, but as mentioned above, the Doppler processing circuit 13 and image generation circuit 14 according to this embodiment, and the medical image processing device 30 equipped with these, can also use a variance threshold.

Figure 12 is an explanatory diagram showing an example of a table for determining a threshold value based on both power and variance.

The threshold determination function 34 may determine the threshold based on both power and variance. For example, if a table that associates both power and variance with a threshold is stored in advance in the memory circuitry 16 (see FIG. 12), the threshold determination function 34 can refer to this table to determine the threshold based on both power and variance. As shown in FIG. 12, this table is preferably set so that data with lower power and higher variance is subject to deletion and hidden in the blanking process. The threshold determination function 34 may also determine the threshold based on at least one of power and variance, and blood flow velocity.

At least one of the embodiments described above can reduce blooming in color Doppler mode.

In the above embodiment, the term "processor" refers to a circuit such as a dedicated or general-purpose CPU (Central Processing Unit), GPU (Graphics Processing Unit), or an Application Specific Integrated Circuit (ASIC), a programmable logic device (for example, a Simple Programmable Logic Device (SPLD), a Complex Programmable Logic Device (CPLD), and a Field Programmable Gate Array (FPGA)). When the processor is a CPU, for example, the processor realizes various functions by reading and executing a program stored in a memory circuit. When the processor is an ASIC, for example, instead of storing a program in a memory circuit, a function corresponding to the program is directly built into the processor circuit as a logic circuit. In this case, the processor realizes various functions by hardware processing that reads and executes the program built into the circuit. Alternatively, the processor can realize various functions by combining software processing and hardware processing.

In addition, in the above embodiment, an example was shown in which a single processor of the processing circuit realizes each function, but a processing circuit may be configured by combining multiple independent processors, and each processor may realize each function. In addition, when multiple processors are provided, a memory circuit for storing programs may be provided separately for each processor, or a single memory circuit may collectively store programs corresponding to the functions of all the processors.

Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are within the scope of the invention and its equivalents as set forth in the claims, as well as the scope and spirit of the invention.

10 Ultrasound diagnostic device 13 Doppler processing circuit 14 Image generation circuit 16 Memory circuit 21 Input interface 22 Display 30 Medical image processing device 34 Threshold determination function 35 Correction function 36 Blank function

Claims (20)

a determination unit that determines at least one of a power threshold value and a variance threshold value when displaying ultrasonic Doppler image data related to a blood flow velocity of the subject on a display unit, based on at least one of a power and a variance of a blood flow signal of the subject;
a blanking processing unit that performs blanking processing to correct at least a part of the data of the ultrasonic Doppler image based on the threshold value;
an image generating unit that generates ultrasonic Doppler image data relating to the blood flow velocity of the subject based on the blanked data and displays the image data on a display unit;
Equipped with
The determination unit is
determining the threshold value based on a histogram of at least one of the power and the variance in a region of interest defined within a set region for obtaining a blood flow signal, and changing the number of bins of the histogram in response to at least one of a size of the set region, a size of the region of interest, an intensity of an echo signal, a velocity of the blood flow signal, a power of the blood flow signal, and a variance of the blood flow signal;
Ultrasound diagnostic equipment. The determination unit is
Repeating the process of creating the histogram and determining the threshold for each display frame.
The ultrasonic diagnostic apparatus according to claim 1 . The determination unit is
determining the threshold value according to at least one of a mode, a median, a mean, and a probability density function of the histogram;
3. The ultrasonic diagnostic apparatus according to claim 1 . The determination unit is
the threshold value is corrected in response to a user instruction and provided to the blanking processing unit;
4. The ultrasonic diagnostic apparatus according to claim 1 . The determination unit is
Varying the number of bins of the histogram in response to a user instruction.
5. The ultrasonic diagnostic apparatus according to claim 1 . The image generating unit includes:
displaying the histogram and information indicating the threshold on the display unit;
6. The ultrasonic diagnostic apparatus according to claim 1 . The determination unit is
Dividing the region of interest into a plurality of regions, creating the histogram for each divided region, and determining the threshold value;
7. The ultrasonic diagnostic apparatus according to claim 1 . The determination unit is
determining whether or not the region of interest needs to be divided, and the number and direction of division of the region of interest, depending on at least one of the intensity of the echo signal and the velocity, power, and variance of the blood flow signal;
The ultrasonic diagnostic apparatus according to claim 7 . The determination unit is
determining whether or not the region of interest is to be divided, and the number and direction of division of the region of interest according to the observation site;
The ultrasonic diagnostic apparatus according to claim 7 . The determination unit is
Dividing the region of interest in a running direction of a blood vessel within the region of interest, creating the histogram for each divided region, and determining the threshold value;
10. The ultrasonic diagnostic apparatus according to claim 1 . The determination unit is
correcting the threshold determined for each of the divided regions based on a distribution of the threshold determined for each of the divided regions;
11. The ultrasonic diagnostic apparatus according to claim 7 . The determination unit is
correcting the threshold value based on an SNR measurement value of the echo signal or blood flow signal, or an attenuation measurement value of the echo signal or blood flow signal;
The ultrasonic diagnostic apparatus according to any one of claims 1 to 11 . The determination unit is
correcting the power threshold so that the power threshold becomes smaller as the position of the region of interest becomes deeper;
13. The ultrasonic diagnostic apparatus according to claim 1. The determination unit is
creating one histogram based on data of a plurality of frames to determine the threshold value;
14. The ultrasonic diagnostic apparatus according to claim 1 . The determination unit is
A histogram is created for each frame to determine a provisional threshold value, and the provisional threshold value is determined by averaging the provisional threshold values of a plurality of adjacent frames.
14. The ultrasonic diagnostic apparatus according to claim 1 . The determination unit is
determining whether to average the provisional thresholds or to use the provisional thresholds as they are according to the change between the provisional thresholds of the plurality of frames, and, if averaging, determining the number of adjacent frames to be averaged;
The ultrasonic diagnostic apparatus according to claim 15 . The determination unit is
determining whether to average the provisional thresholds or use the provisional thresholds as they are according to the position of the observation site or the region of interest, and, if averaging, determining the number of adjacent frames to average;
16. The ultrasonic diagnostic apparatus according to claim 14 or 15 . The determination unit is
determining the threshold value based on a blood flow velocity and at least one of the power and the variance;
18. The ultrasonic diagnostic apparatus according to claim 1. a determination unit that determines at least one of a power threshold value and a variance threshold value when displaying ultrasonic Doppler image data related to a blood flow velocity of the subject on a display unit, based on at least one of a power and a variance of a blood flow signal of the subject;
a blanking processing unit that performs blanking processing to correct at least a part of the data of the ultrasonic Doppler image based on the threshold value;
an image generating unit that displays ultrasonic Doppler image data relating to the blood flow velocity of the subject on a display unit based on the data after the blanking process;
Equipped with
The determination unit is
determining the threshold value based on a histogram of at least one of the power and the variance in a region of interest defined within a set region for obtaining a blood flow signal, and changing the number of bins of the histogram in response to at least one of a size of the set region, a size of the region of interest, an intensity of an echo signal, a velocity of the blood flow signal, a power of the blood flow signal, and a variance of the blood flow signal;
Medical imaging equipment . On the computer,
determining at least one of a power threshold and a variance threshold when displaying ultrasonic Doppler image data related to the velocity of blood flow in the subject on a display unit, based on at least one of the power and variance of a blood flow signal in the subject;
a step of performing blanking processing to correct at least a part of the data of the ultrasonic Doppler image based on the threshold value;
displaying ultrasonic Doppler image data relating to the blood flow velocity of the subject on a display unit based on the blanked data;
A medical image processing program for executing
The step of determining at least one of the power threshold and the variance threshold comprises:
determining the threshold value based on a histogram of at least one of the power and the variance in a region of interest defined within a set region for obtaining a blood flow signal ;
changing the number of bins of the histogram in response to at least one of the size of the set region, the size of the region of interest, the intensity of the echo signal, the velocity of the blood flow signal, the power of the blood flow signal, and the variance of the blood flow signal ;
including,
A medical image processing program .

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