JP7432426B2 - Ultrasonic diagnostic equipment, signal processing equipment, and signal processing programs - Google Patents

Description

The present invention relates to an ultrasonic diagnostic apparatus, and relates to a method for measuring acoustic attenuation characteristics within a subject.

Medical image display devices, such as ultrasound, MRI (Magnetic Resonance Imaging) devices, and X-ray CT (Computed Tomography) devices, are widely used to present in-vivo information that cannot be seen with the naked eye in the form of numerical values or images. has been done. Among these, ultrasonic imaging devices that display images using ultrasound have higher temporal resolution than other devices, and have the ability, for example, to image a beating heart without blurring.

An ultrasonic diagnostic apparatus transmits ultrasonic waves toward an object to be examined, receives reflected signals from scatterers (hereinafter referred to as received RF (Radio Frequency) signals), and forms an image. Basically, an ultrasound image (hereinafter referred to as B image) is generated by measuring the distance to the scatterer based on the time required for transmission and reception and the speed of sound, and constructing a spatial distribution of brightness based on the intensity of ultrasound energy.

In addition, it has been proposed to develop technology for diagnosing diseases using ultrasound diagnostic equipment by quantitatively measuring acoustic characteristics such as blood flow velocity, tissue hardness, and attenuation characteristics using received signals. There is.

For example, Patent Document 1 discloses a method for determining attenuation characteristics of living tissue. In Patent Document 1, first and second focused ultrasound beams having different focal lengths are transmitted from a probe to a target object, and the first and second focused ultrasound beams at a predetermined measurement point of the target object are transmitted. Received signals from the two ultrasonic beams are obtained respectively. Next, the attenuation characteristic calculation unit uses the change in the depth direction of the ultrasonic energy of the received signal by the first ultrasonic beam and the received signal by the second ultrasonic beam obtained at the predetermined measurement point to We are looking for the attenuation characteristics of

Furthermore, Patent Document 2 discloses a technology that performs image filtering processing in order to reduce various noises and speckles included in ultrasound images and emphasize information regarding the subject's tissue. A method has been proposed in which when the tissue structure is aligned in a specific direction when viewed in a local region, the filter parameters are adjusted to make the structure clear. That is, the direction of the edge of the local region in the ultrasound image, the size of the edge in the local region, and the uniformity of the direction of the edge in the local region are calculated, and the parameters of the filter are set.

Patent No. 6457107 Japanese Patent Application Publication No. 2012-75882

One of the acoustic properties of living tissue is the attenuation property of acoustic energy propagating inside the tissue. The attenuation characteristic is a characteristic in which when an ultrasonic wave propagates in a medium, the ultrasonic energy is attenuated due to absorption and scattering phenomena depending on the propagation distance. Fatty liver, a type of liver disease, is known to cause greater attenuation of acoustic energy compared to normal liver. Therefore, it is expected that measuring the attenuation rate will be useful in diagnosing diseases.

Although the signal strength of ultrasound decreases smoothly as the propagation distance increases, it actually includes random changes in signal strength (speckles). Since the attenuation rate is calculated from the rate of decrease in signal strength per distance, there is a problem in that this speckle causes variations in the measured values and reduces the accuracy of the attenuation rate calculation.

In addition, the ultrasound diagnostic equipment is equipped with a Time Gain Control (TGC) function that applies a gain to the received signal according to the depth, and the brightness of the B image, which represents the intensity distribution of ultrasound energy as a brightness distribution, is Adjust so that it is uniform from the top to the bottom. However, the actual attenuation of the received RF signal in the depth direction may not depend on the depth. For example, when transmitted ultrasound is focused and irradiated, the intensity of the received RF signal increases near the focal point of the transmitted ultrasound.

Furthermore, the actual attenuation of the received RF signal occurs not only in the depth direction but also two-dimensionally in the depth direction and the azimuth direction. For example, when diagnosing liver disease, the sound speed, density, and attenuation rate differ between the liver parenchyma, subcutaneous tissue, cyst, and diaphragm, so ultrasound waves are reflected, refracted, and scattered at the boundaries of structures, and Affects the sound pressure profile in the azimuth direction two-dimensionally.

Therefore, with the TGC function only in the depth direction, it is not possible to make the brightness distribution of the B image uniform in the depth direction, and the morphology of the living tissue may still be difficult to see on the B image, making diagnosis difficult. be.

An object of the present invention is to enable accurate calculation of the attenuation rate of ultrasonic waves regardless of direction.

In order to achieve the above object, the ultrasound diagnostic apparatus of the present invention receives signals from an ultrasound probe and performs reception beamforming, thereby providing a reception signal for each of a plurality of reception scanning lines set in an imaging area. and a signal processing unit that processes the received signal. The signal processing unit includes a two-dimensional ROI setting unit that sets a plurality of two-dimensional ROIs in a two-dimensional signal space in which a plurality of received signals are arranged in the order of received scanning lines, and a two-dimensional ROI setting unit that determines a representative value using the signal in the ROI. and a representative value calculation unit that uses the representative value as the processed signal value of the representative point set within the ROI.

According to the ultrasound diagnostic apparatus of the present invention, since a plurality of two-dimensional ROIs are set and each representative value is used as the processed signal value, the attenuation rate of ultrasound can be calculated with high accuracy regardless of the direction. .

1 is a block diagram of an ultrasonic diagnostic apparatus according to Embodiment 1 of the present invention. 1 is a flowchart showing the operation of the ultrasonic diagnostic apparatus of Embodiment 1. FIG. 2 is an explanatory diagram showing transmission and reception to and from the inspection target in Embodiment 1. FIG. FIG. 3 is an explanatory diagram showing a two-dimensional signal space in which received RF signals are arranged and a set ROI according to the first embodiment. 1 is a flowchart showing the operation of the ultrasonic diagnostic apparatus of Embodiment 1. FIG. 3 is an explanatory diagram showing processing for determining ROI suitability in the first embodiment. 1 is a flowchart showing the operation of the ultrasonic diagnostic apparatus of Embodiment 1. FIG. 2 is an explanatory diagram showing a valid ROI and an invalid ROI in a two-dimensional signal space of a received RF signal in the first embodiment. FIG. 3 is an explanatory diagram showing the distribution of an effective region (effective RO) I and an invalid region (ineffective ROI) in a two-dimensional signal space of a received RF signal in the first embodiment. 1 is a flowchart showing the operation of the ultrasonic diagnostic apparatus of Embodiment 1. FIG. 3 is an explanatory diagram showing the processing of the representative value suitability determination unit in the first embodiment. 7 is a flowchart showing the operation of the ultrasound diagnostic apparatus according to the second embodiment. An example of a display screen in Embodiment 2. 7 is a flowchart showing the operation of the ultrasonic diagnostic apparatus of Embodiment 3. An example of a display screen in Embodiment 3. An example of a display screen in Embodiment 3.

Embodiments of the present invention will be described below with reference to the drawings.

<<Embodiment 1>>
<Overall configuration of ultrasound diagnostic equipment>
FIG. 1 shows a block diagram of a configuration example of an ultrasonic diagnostic apparatus 1 according to an embodiment. The ultrasonic transmitter/receiver 1 of this embodiment includes a transmitter/receiver controller 20 and a signal processor 30. Further, the probe 10 is connected to the transmission/reception control section 20 . The external input device 13 and the display section 16 are connected to the signal processing section 30 .

The transmission/reception control unit 20 includes a transmission beamformer 21 and a reception beamformer 22. The transmission beamformer 21 generates a transmission signal and outputs it to the arrayed transducers forming the probe 10. The plurality of transducers of the probe 10 convert the transmission signals into ultrasonic waves and transmit them toward the inspection target 100. Among the ultrasound waves reflected or scattered by the inspection object 100, the ultrasound waves that reach the probe 10 are converted into electrical signals by each transducer of the probe 10. The reception beamformer 22 receives the electric signals of each transducer, delays and adds them (phasing addition) so as to focus on a plurality of points on the reception scanning line set in the imaging area, thereby converting the received signals ( (hereinafter referred to as a received RF signal) (reception beamforming).

The signal processing unit 30 includes a two-dimensional ROI setting unit 31, an ROI compatibility analysis unit 32, a representative value calculation unit 33, a representative value compatibility determination unit 34, an interpolation unit 35, an image generation unit 36, and an attenuation and a rate calculation section 37.

The two-dimensional ROI setting unit 31 forms a two-dimensional signal space in which a plurality of received RF signals are arranged in the order of reception scanning lines, and sets a plurality of two-dimensional ROIs in the two-dimensional signal space.

The representative value calculating unit 33 obtains a representative value using the signal within the ROI, and uses the obtained representative value as the processed signal value of the representative point set within the ROI.

In this way, multiple two-dimensional ROIs are set in the two-dimensional signal space of the received RF signal, the representative value of each is determined, and the specifications included in the received signal within the ROI are used to obtain the processed signal value of the representative value of the ROI. can be reduced in two-dimensional space. Thereby, the attenuation rate of ultrasonic waves can be calculated with high precision regardless of the direction.

It is preferable that the two-dimensional ROI setting unit 31 sets the plurality of ROIs at positions shifted from each other in at least one of the direction along the reception scanning line in the two-dimensional signal space and the arrangement direction of the reception scanning line.

At this time, the two-dimensional ROI setting unit 31 may adaptively change the size and shape of the ROI to be set based on the received RF signal.

The ROI compatibility analysis unit 32 determines whether the signal strength distribution within the ROI conforms to a predetermined signal strength distribution, defines the conforming ROI as a valid ROI, and defines the nonconforming ROI as a valid ROI. Set as invalid ROI.

The representative value suitability determination section 34 determines whether the distribution of representative values for the plurality of ROIs calculated by the representative value calculation section 33 conforms to predetermined conditions. The representative value suitability determination unit 34 does not adopt a representative value that does not meet the conditions as a processed signal value. For example, the representative value suitability determination unit 34 determines that the condition is met if the distribution of signal intensities of the representative values of the plurality of ROIs gradually decreases along the sound wave propagation direction.

The interpolation unit 35 uses representative values of a plurality of ROIs in the two-dimensional signal space to obtain signal values in the two-dimensional signal space between the ROIs by interpolation.

The image generation unit 36 generates a B-mode image using the processed signal. The image generation unit 36 may be configured to optimize the brightness value of the B-mode image using the processed signal.

The attenuation rate calculation unit 37 uses the processed signal to determine the attenuation rate in the depth direction.

The signal processing unit 30 is composed of a computer or the like that includes a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit) and a memory, and the CPU reads and executes a program stored in the memory. Accordingly, the above-mentioned two-dimensional ROI setting section 31, ROI suitability analysis section 32, representative value calculation section 33, representative value suitability determination section 34, interpolation section 35, image generation section 36, and attenuation rate calculation The functions of the section 37 are realized by software. Note that part or all of the signal processing unit 30 can also be realized by hardware. For example, the signal processing unit 7 is configured using a custom IC such as an ASIC (Application Specific Integrated Circuit) or a programmable IC such as an FPGA (Field-Programmable Gate Array), and the functions of each part of the signal processing unit 7 are realized. All you have to do is design the circuit accordingly.

FIG. 2 shows a flowchart of a configuration example of the ultrasonic diagnostic apparatus according to the embodiment. The entire operation will be explained along this flowchart.

First, ultrasonic waves are transmitted and received from the probe 10 as shown in FIG. Specifically, the transmission signal generated by the transmission beam former 21 is output to the probe 10, and the transmission ultrasound 301, which is an ultrasound beam, is transmitted from the probe 10, and the scattering inside the inspection object 100 is transmitted. The probe 10 receives reflected ultrasound waves 302 scattered from the body 303. The reception beamformer 22 generates a reception RF signal along a set reception scanning line by performing phasing and addition of the signals from the probe 10. The received RF signal is subjected to phasing and addition processing, and then further compressed using a common logarithm.

Note that the received RF signal includes random signal intensity changes called speckles. This occurs when the ultrasonic waves scattered from the scatterers 303 in the medium randomly interfere with each other, and changes depending on the acoustic characteristics of the medium and the shape and density of the scatterers in the medium. Furthermore, it is assumed that the medium to be inspected has attenuation. Therefore, when an ultrasonic wave propagates inside this medium, the ultrasonic energy decreases depending on the propagation distance.

In step 201 , a received RF signal along a receiving scanning line is input from the receiving beamformer 22 to the two-dimensional ROI setting unit 31 .

The two-dimensional ROI setting unit 31 forms a two-dimensional signal space by arranging a plurality of received RF signals in the horizontal axis (azimuth) direction (the direction in which the transducers of the probe are arranged) in the order of the received scanning lines. Therefore, in this two-dimensional signal space, the horizontal axis corresponds to the azimuth direction, that is, the direction in which the transducers of the probe 10 are arranged, and the vertical axis corresponds to the depth direction.

と表される。なお、iは探触子の振動子の番号、tは時間を示す。 Next, in step 202, the received signal is corrected using the sound pressure profile of the transmitted ultrasound to obtain a corrected signal. This corrects the signal strength distribution of the received RF signal, which is caused by the strength of the sound pressure of the transmitted ultrasound. The sound pressure profile is measured or calculated in advance using a homogeneous phantom or simulation, and is stored in a memory within the ultrasound diagnostic apparatus. As a correction method, the received RF signal is M(i,t), the sound pressure profile is R(i,t), and the signal after correction is C(i,t).

It is expressed as Note that i indicates the number of the transducer of the probe, and t indicates the time.

Next, in step 203, the two-dimensional ROI setting unit 31 determines the specifications and positions of a plurality of ROIs to be set. Here, the two-dimensional ROI setting unit 31 sets the plurality of ROIs at positions shifted from each other in at least one of the direction along the reception scanning line in the two-dimensional signal space and the arrangement direction of the reception scanning lines. Furthermore, the two-dimensional ROI setting unit 31 adaptively changes the size and shape of the ROI to be set based on the received RF signal.

An example of ROI specifications and a position setting method will be explained using FIG. 4. The ROI 401 has a depth direction size of the number of samples h and an azimuth direction size of the size of the sample number w in the received RF signal. This is the set ROI. The ROI 402 has the same size as the ROI 401, but its center position is set at a different position by the number of samples dh in the depth direction and the number of samples dw in the azimuth direction. Therefore, with respect to the representative point (xn, zn) of the ROI 401, the position of the representative point of the ROI 402 is (xn+dw, zn+dhs).

The two-dimensional ROI setting unit 31 determines the size in the depth direction (number of samples h) and the size in the azimuth direction (number of samples w) of the ROIs 401 and 402, as well as the amount of positional deviation between the ROI 401 and the ROI 402 (the number of samples in the depth direction). An example of a method for determining the number of samples dh and the number of samples in the azimuth direction dws will be explained using FIG.

In step 501 of FIG. 5, the two-dimensional ROI setting unit 31 receives the two-dimensional signal space formed by arranging the received RF signals in step 201. Next, in step 502, a two-dimensional Fourier transform is performed to obtain the spatial frequency distribution of the received RF signal, and the two-dimensional ROI setting unit 31 calculates the size of the speckle in the azimuth direction and the depth direction based on this spatial frequency distribution. Find the distribution.

Next, in step 503, the two-dimensional ROI setting unit 31 determines the size of the ROI based on the spatial size distribution of speckles. As a specific determination method, for example, the number of samples h in the depth direction of the ROI, the number of samples in the azimuth direction w, the number of moving samples in the depth direction dh, the number of moving samples in the azimuth direction dw, and the spatial size of speckle Multiply the average of .

Next, in step 204 of FIG. 2, the ROI compatibility analysis unit 32 determines the compatibility of the ROI set by the two-dimensional ROI setting unit 31 to determine whether or not it will be used in the processing from step 205 onwards. A schematic diagram of the method for determining compatibility is shown in FIG. First, when the ROIs set by the two-dimensional ROI setting unit 31 are ROI 601 and ROI 602, the ROI compatibility analysis unit 32 analyzes the signal strength (brightness) distribution 603 and signal strength ( Luminance) distribution 604 is calculated. Then, the ROI suitability analysis unit 32 quantifies the difference between each signal intensity distribution and the ideal data 605. Note that the ideal data is calculated in advance using a homogeneous phantom or simulation, and is stored in the memory of the ultrasonic diagnostic apparatus.

In FIG. 6, a signal intensity (brightness) distribution 603 of an ROI 601 is very similar to an ideal distribution 605. On the other hand, the signal intensity (luminance) distribution 604 of the ROI 602 including the structure 606 deviates from the ideal distribution 605. The ROI suitability analysis unit 32 determines the suitability of the ROI based on the degree of deviation from the ideal distribution 607.

For the ROI that is determined to be compatible by the ROI suitability analysis unit 32, in the next step 205, the representative value calculation unit 33 calculates a representative value.

The process flow of calculating the degree of deviation by the ROI suitability analysis unit 32 and calculating the representative value by the representative value calculation unit 33 in steps 204 and 205 will be specifically explained using the flow of FIG. 7.

In step 701 of FIG. 7, the two-dimensional ROI setting unit 31 determines and sets the ROI setting position based on the position of the ROI set immediately before, as shown in FIG.

In step 702, the ROI suitability analysis unit 32 calculates a signal strength (luminance) histogram Rmeasured in the ROI.

として算出する。 In step 703, the ROI suitability analysis unit 32 calculates the signal strength in the ROI (the degree of deviation S between the brightness histogram Rmeasured and the ideal brightness histogram Rmodel).

Calculated as

In step 704, the ROI suitability analysis unit 32 determines suitability by comparing the preset threshold value and the degree of deviation S calculated by equation (2). That is, the ROI suitability analysis unit 32 determines that there is suitability when the deviation degree S is smaller than a preset threshold value.

In step 705, for the ROI determined to be compatible, the ROI suitability analysis unit 32 calculates the value μ of the representative point (xn, zn) of the ROI as a valid ROI from the value in the ROI. As the value of the representative point, values such as the average value, median value, maximum value, and minimum value in the ROI are used. In this embodiment, the position of the first representative point is the center point of the ROI, but it is not limited to the center point, but may be a point at a predetermined position such as the center of gravity, the midpoint of one of the sides, or the four corner points. Good too.

In addition, the ROI suitability analysis unit 32 sets the value of the representative point to a constant τ in step 706 as an invalid ROI for the ROI determined to have no suitability. Note that τ determines a constant such as 0 that does not appear on the received RF signal.

In step 207, the ROI suitability analysis unit 32 stores the calculated representative value in a memory (not shown).

Finally, in step 208 (step 707), the ROI suitability analysis unit 32 repeats the above process until analysis of all regions is completed.

FIG. 8 is a diagram showing the process during steps 701 to 707 in FIG. 7. It can be seen that a valid ROI 803 determined to be compatible and an invalid ROI 804 determined not to be compatible are located in the two-dimensional signal space 805 of the received RF signal. A representative point 802 is set for each ROI.

FIG. 9 is a diagram showing the state when the processing from steps 701 to 707 in FIG. 7 is completed. When the processing is completed, an invalid region 903, which is a collection of representative points of the invalid ROI, and a valid region 904, which is a collection of representative points of the valid ROI, are distributed in the received RF signal 805.

Next, the representative value suitability determining section 34 determines whether the distribution of representative values for the plurality of ROIs calculated by the representative value calculating section 33 conforms to predetermined conditions.

First, in step 208 of FIG. 2, the representative value suitability determination unit 34 selects a representative value. FIG. 10 is a flowchart of representative value selection.

First, in step 1001, the representative value compatibility determination unit 34 connects representative points with line segments, and in step 1002, creates an area 1102 surrounded by three points as shown in FIG.

Next, in step 1003, the representative value suitability determining unit 34 determines whether the invalid region (invalid ROI) 903 shown in FIG. 9 is included in the region 1102 surrounded by the three points.

Finally, in step 1004, the representative value compatibility determining unit 34 uses the values of the three representative points to calculate the gradient of the representative value in the direction of the ultrasound beam passing through the area surrounded by the three points. .

FIG. 11 illustrates the operation of the representative value suitability determination unit 34 in step 1004. In FIG. 11, the representative value compatibility determination unit 34 sets a beam vector 1101 that passes through an area 1102 surrounded by three points k1, k2, and k3, and determines the representative value in the direction of the beam vector 1101. Calculate the slope.

Next, in step 1005, the representative value suitability determination unit 34 selects the representative value as appropriate if the gradient in the direction of the beam vector 1101 is negative.

Here, the reason why the representative value suitability determination unit 34 selects the beam vector 1101 as appropriate when the gradient in the direction is negative is that the ultrasonic wave attenuates as it propagates through the inspection object 100. It is assumed that the energy always decreases along the ultrasound beam direction, that is, the sound wave propagation direction, that is, the gradient of the representative value is negative.

However, since the energy of an invalid region (invalid ROI) whose brightness distribution is determined to be inappropriate by the ROI suitability analysis unit 32 does not necessarily decrease, it is removed in advance in step 1003.

In step 209 of FIG. 2, two-dimensional interpolation processing is performed between the representative points selected in step 208. Thereby, the distribution of the representative points can be made smoother, and the image generated by the image generation unit 36 can be made smoother. Furthermore, even when a plurality of ROIs are arranged at intervals, signal values between the ROIs can be calculated, so processing speed can be improved. Note that the interpolation method uses a known method such as two-dimensional linear interpolation, two-dimensional spline interpolation, or two-dimensional B-spline interpolation.

As described above, it is possible to generate a signal (representative value and interpolated value) from which speckles are removed in the depth direction and azimuth direction in a two-dimensional space.

Finally, in step 210 of FIG. 2, the interpolation unit 35 generates an image. The image generation method will be described in the second and third embodiments.

<<Embodiment 2>>
FIG. 12 shows an example of a flowchart of the image generation process of the B image by the image generation unit 36 in step 210 of FIG.

First, in step 1201, the interpolated signal output from step 209 in FIG. 2 is input to the image generation unit 36.

Next, in step 1202, the image generation unit 36 reads the sound pressure profile. Note that this sound pressure profile is the same as that used in the sound pressure profile correction in step 202 of FIG.

と表される。なおBは、ユーザが設定する所望のB像の輝度である。 Next, in step 1203, the image generation unit 36 calculates a two-dimensional correction gain for performing gain correction for the entire drawing area of the B image. The two-dimensional correction gain G(I,t) is as follows, assuming that the signal after interpolation processing is S(I,t) and the sound pressure profile is P(I,t).

It is expressed as Note that B is the desired brightness of the B image set by the user.

Next, in step 1204, the received RF signal is read.

と表される。 Next, in step 1205, the received RF signal read in step 1205 is corrected using a two-dimensional correction gain to create a corrected signal. Assuming that the signal after correction is C(i,t) and the received RF signal is M(i,t),

It is expressed as

In step 1206, the image generation unit 36 generates a B image using the corrected signal C(i,t) created by equation (4), thereby obtaining a B image corrected with the two-dimensional correction gain. be able to. The image generation section 36 displays the generated image on the display section 16.

FIG. 13 is a display example of the corrected B image created in the second embodiment. A gain map 1302 and a corrected B image 1303 are displayed side by side, and the gain map 1302 includes the representative points 1202 selected in step 208 of FIG. ROI) 1201 is shown. The user can judge whether the correction is appropriately performed by comparing not only the B image alone but also the gain map as shown in FIG. 13.

<<Embodiment 3>>
FIG. 14 shows an example of a flowchart of the attenuation rate map image generation process performed by the image generation unit 36 in step 210 of FIG. The attenuation rate is the amount of attenuation of ultrasonic energy per unit distance and unit frequency.

In the third embodiment, first, in step 1401, the interpolated signal output from step 209 in FIG. 2 is input to the image generation unit 36.

Next, in step 1402, the image generation unit 36 converts the interpolated signal into a distance by multiplying the time axis by the sound speed value (approximately 1540 m/s in a living body).

Next, in step 1403, the image generation unit 36 calculates the gradient in the beam direction. This gradient in the beam direction indicates the amount of attenuation of the ultrasonic energy as the ultrasonic wave propagates.

と表される。 Furthermore, in step 1404, the image generation unit 36 calculates an attenuation rate from the beam direction gradient calculated in step 1402. The attenuation rate α [dB/MHz/cm] is given by the following: If the slope in the beam direction is D [dB/cm] and the frequency used for transmission is f [MHz],

It is expressed as

The image generation unit 36 performs the above processing on the entire area within the attenuation rate map display area preset by the user via the external input device 13, and creates an attenuation rate map. The image generation unit 36 displays the created attenuation rate map on the display unit 16.

FIG. 15 is an example of the display format of the attenuation rate map on the display unit 16. An attenuation rate map display area 1503 is superimposed on the ultrasound image 1500 to display the attenuation rate map. In this display form, the user can compare the attenuation rate map, the representative point 1502, and the invalid area 1501. Therefore, the user can judge whether the attenuation rate is being measured appropriately from the way the representative points and invalid areas are selected.

FIG. 16 is another example of the display format of the attenuation rate map on the display unit 16. An attenuation rate map display area 1603 is superimposed on the ultrasound image 1600. The magnitude of the attenuation rate is indicated by a color corresponding to the color bar defined by the attenuation rate display range 1605. In this display form, the user can determine whether the invalid value 1604 is appropriately detected and the attenuation rate is appropriately measured by comparing the B image 1602 and the attenuation rate map.

As described above, the ultrasonic diagnostic apparatus of the first embodiment can generate signals (representative values and interpolated values) from which speckles are removed in the depth direction and azimuth direction in a two-dimensional space. Therefore, using this signal, the B image may be generated as in the second embodiment, or the attenuation rate may be calculated as in the third embodiment.

The B image is a high-definition image because the attenuation due to ultrasound propagation has been accurately corrected. Therefore, the user can make a diagnosis by looking at this high-definition B image.

Also. By calculating and displaying the attenuation rate as in the third embodiment, if the attenuation rate is greater than a predetermined value, it can be useful for determining a disease characterized by the attenuation rate, such as fatty liver.

DESCRIPTION OF SYMBOLS 1: Ultrasonic transmitter/receiver, 10: Probe, 13: External input device, 16: Display section, 20: Transmission/reception control section, 21: Transmission beamformer, 22: Reception beamformer, 21: Transmission beamformer, 30: Signal processing unit, 31: Two-dimensional ROI setting unit, 32: ROI compatibility analysis unit, 33: Representative value calculation unit, 34: Representative value compatibility determination unit, 35: Interpolation unit, 36: Image generation unit, 37: Attenuation Rate calculation unit, 100: Inspection target

Claims (7)

a reception beamformer that receives signals from an ultrasound probe and performs reception beamforming to generate reception signals for each of a plurality of reception scanning lines set in an imaging region; and a signal processing unit that processes the reception signals. and has
The signal processing section includes:
a two-dimensional ROI setting unit that sets a plurality of two-dimensional ROIs in a two-dimensional signal space in which the plurality of received signals are arranged in the order of the received scanning lines;
a representative value calculation unit that obtains a representative value using the signal within the ROI and uses the obtained representative value as a processed signal value of a representative point set within the ROI;
a representative value suitability determination unit that determines whether the distribution of the representative values for the plurality of ROIs calculated by the representative value calculation unit conforms to predetermined conditions;
The ultrasound diagnostic apparatus is characterized in that the representative value suitability determination unit does not adopt a representative value that does not meet the conditions as the processed signal value. 2. The ultrasonic diagnostic apparatus according to claim 1, wherein the representative value compatibility determination unit determines that the distribution of signal intensities of the representative values of the plurality of ROIs gradually decreases along the sound wave propagation direction. An ultrasonic diagnostic apparatus characterized in that, if the condition is met, it is determined that the condition is met. a reception beamformer that receives signals from an ultrasound probe and performs reception beamforming to generate reception signals for each of a plurality of reception scanning lines set in an imaging region; and a signal processing unit that processes the reception signals. and has
The signal processing section includes:
a two-dimensional ROI setting unit that sets a plurality of two-dimensional ROIs in a two-dimensional signal space in which the plurality of received signals are arranged in the order of the received scanning lines;
a representative value calculation unit that obtains a representative value using the signal within the ROI and uses the obtained representative value as a processed signal value of a representative point set within the ROI;
An ultrasonic diagnostic apparatus comprising: an image generation section that generates a B-mode image using the processed signal value. a reception beamformer that receives signals from an ultrasound probe and performs reception beamforming to generate reception signals for each of a plurality of reception scanning lines set in an imaging region; and a signal processing unit that processes the reception signals. and has
The signal processing section includes:
a two-dimensional ROI setting unit that sets a plurality of two-dimensional ROIs in a two-dimensional signal space in which the plurality of received signals are arranged in the order of the received scanning lines;
a representative value calculation unit that obtains a representative value using the signal within the ROI and uses the obtained representative value as a processed signal value of a representative point set within the ROI;
An ultrasonic diagnostic apparatus comprising: an image generation unit that optimizes a brightness value of a B-mode image using the processed signal value. a reception beamformer that receives signals from an ultrasound probe and performs reception beamforming to generate reception signals for each of a plurality of reception scanning lines set in an imaging region; and a signal processing unit that processes the reception signals. and has
The signal processing section includes:
a two-dimensional ROI setting unit that sets a plurality of two-dimensional ROIs in a two-dimensional signal space in which the plurality of received signals are arranged in the order of the received scanning lines;
a representative value calculation unit that obtains a representative value using the signal within the ROI and uses the obtained representative value as a processed signal value of a representative point set within the ROI;
an interpolation unit that obtains signal values in the two-dimensional signal space between the ROIs by interpolation using the representative values of the plurality of ROIs in the two-dimensional signal space. Diagnostic equipment. a two-dimensional ROI setting unit that sets a plurality of two-dimensional ROIs in a two-dimensional signal space in which received signals after receiving beamforming are arranged in order of receiving scanning lines;
a representative value calculation unit that obtains a representative value using the signal within the ROI and uses the obtained representative value as a processed signal value of a representative point set within the ROI ;
a representative value suitability determination unit that determines whether the distribution of the representative values for the plurality of ROIs calculated by the representative value calculation unit conforms to predetermined conditions;
The signal processing device, wherein the representative value suitability determination unit does not adopt a representative value that does not meet the conditions as the processed signal value . a two-dimensional ROI setting means for arranging the received signals after receiving beamforming by the computer in the order of the received scanning lines, and setting a plurality of two-dimensional ROIs in the formed two-dimensional signal space;
representative value calculating means for determining a representative value using the signal within the ROI, and determining the determined representative value as a processed signal value of a representative point set within the ROI ;
A signal processing program that functions as a representative value suitability determining means for determining whether the distribution of the representative values for the plurality of ROIs calculated by the representative value calculating means conforms to a predetermined condition. ,
The representative value suitability determination means does not adopt a representative value that does not meet the conditions as the processed signal value.
A signal processing program characterized by :

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