Ultrasonic diagnostic apparatus

Abstract

To set a display state of Doppler waveform so as to make the Doppler waveform easy to see.SOLUTION: An ultrasonic diagnostic apparatus 100 comprises a transmission unit 12, a reception unit 20, and an information processing unit 26. The transmission unit 12 transmits ultrasonic waves to an analyte 18 with an ultrasonic probe 14. The reception unit 20 receives the ultrasonic waves reflected by the analyte 18, with the ultrasonic probe 14. The information processing unit 26 executes processing on a reception signal output from the reception unit 20. The information processing unit generates Doppler waveform data based on the reception signal, obtains the maximum value, the minimum value, and the reference value of a Doppler waveform line obtained from the Doppler waveform data, and determines a display range of a blood flow rate shown by a Doppler waveform, based on the maximum value, the minimum value, and the reference value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an ultrasonic diagnostic apparatus, and more particularly to processing for displaying a Doppler waveform. [Background technology]

[0002] Ultrasound diagnostic devices that observe a subject by transmitting and receiving ultrasonic waves are widely used. In general, ultrasound diagnostic devices have a function of displaying a Doppler waveform that indicates blood flow velocity. Waveform characteristic values ​​such as maximum, minimum, and average values ​​of the Doppler waveform vary depending on the observed part. Therefore, a technology has been devised that adjusts the scale when displaying the Doppler waveform to make it easier for users to observe the Doppler waveform.

[0003] The following Patent Document 1 describes adjusting the Doppler velocity range based on a statistical value for the distribution of at least one of the maximum flow velocity and the average flow velocity of the trace waveform in the frequency direction of the spectrum signal. Patent Document 1 also describes determining the multiple of the baseline and the estimated upper and lower limits of the velocity range to be set as the display range based on the maximum positive value and the maximum negative value.

[0004] Patent Document 2 describes an ultrasonic color Doppler imaging system that determines whether a blood vessel to be diagnosed is an artery or a vein based on a pulsatility index PI and a resistance index RI of blood flow velocity. Patent Document 3 describes a technology for generating Doppler image data that represents blood flow velocity by color. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-88943 A [Patent Document 2] Japanese Patent Application Publication No. 11-235342 [Patent Document 3] JP 2016-87302 A Summary of the Invention [Problem to be solved by the invention]

[0006] The waveform characteristic values ​​of the Doppler waveform vary depending on the observation site. Therefore, if the Doppler waveform is displayed at a constant scale, it may be difficult to see the Doppler waveform.

[0007] An object of the present invention is to set the display state of a Doppler waveform so that the Doppler waveform can be easily viewed. [Means for solving the problem]

[0008] The present invention comprises a transmitting unit which transmits ultrasonic waves to a subject by an ultrasonic probe, a receiving unit which receives the ultrasonic waves reflected by the subject by the ultrasonic probe, and an information processing unit which performs processing on a received signal output from the receiving unit, wherein the information processing unit generates Doppler waveform data based on the received signal, determines a maximum value, a minimum value and a reference value of a Doppler waveform line obtained from the Doppler waveform data, and determines a display range of the blood flow velocity indicated by the Doppler waveform based on the maximum value, the minimum value and the reference value.

[0009] Preferably, the reference value is a Doppler waveform average value, 0 or the center of gravity.

[0010] Desirably, the information processing unit determines the display range by multiplying the greater of the absolute value of the value obtained by subtracting the reference value from the maximum value and the absolute value of the value obtained by subtracting the reference value from the minimum value by a predetermined scale factor.

[0011] Preferably, the scale factor is determined according to an index value obtained by dividing the absolute value of a value obtained by subtracting the minimum value from the maximum value by the greater of the absolute values ​​of the maximum value and the minimum value.

[0012] Desirably, the information processing unit calculates the scale factor according to the value of a scale function that obtains the scale factor by providing an index value, the scale function indicating a curve passing through a plurality of set points or a curve approximated to a curve passing through a plurality of the set points, the index value being a value indicating the difference between the maximum value and the minimum value, and the set point being a point on a coordinate plane that corresponds to the index value and the scale factor.

[0013] Preferably, the information processing unit sets the set point via a user interface.

[0014] Preferably, the information processing section determines the scale factor in accordance with a diagnosis situation.

[0015] Preferably, the information processing unit obtains the scale factor via a user interface.

[0016] Preferably, the information processing unit acquires a signal indicative of the subject's pulsation from a pulsation detection device that detects the subject's pulsation, and determines the display range at a timing according to the subject's pulsation.

[0017] Preferably, a repetition frequency at which the transmitting unit transmits the ultrasonic waves is set in accordance with the display range.

[0018] Preferably, the information processing unit determines the display range in accordance with an area of ​​a region between the Doppler waveform line and a reference line indicated by the reference value. Effect of the Invention

[0019] According to the present invention, the display state of the ultrasound diagnostic device can be set so as to make the Doppler waveform easier to see. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram showing the configuration of an ultrasonic diagnostic apparatus. [Diagram 2] FIG. 2 is a diagram showing an example of a Doppler waveform. [Diagram 3] FIG. 1 is a diagram showing an example of a B-mode color Doppler image and a Doppler waveform. [Figure 4] FIG. 13 shows a Doppler waveform with a Doppler waveform line. [Diagram 5] FIG. 13 is a diagram illustrating an example of a scale function. [Figure 6] FIG. 1 is a diagram showing an example of a B-mode color Doppler image and a Doppler waveform. [Figure 7] FIG. 13 shows a Doppler waveform with a Doppler waveform line. [Figure 8] FIG. 1 is a diagram showing an example of a B-mode color Doppler image and a Doppler waveform. [Figure 9] FIG. 13 shows a Doppler waveform with a Doppler waveform line. [Figure 10] FIG. 13 is a diagram illustrating update timing of a scale factor. [Figure 11] FIG. 13 is a diagram illustrating update timing of a scale factor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Each embodiment of the present invention will be described with reference to the drawings. The same components shown in multiple drawings are given the same reference numerals and their description will be omitted. Fig. 1 shows the configuration of an ultrasonic diagnostic device 100 according to an embodiment of the present invention. The ultrasonic diagnostic device 100 includes a beam control unit 10, a transmission unit 12, an ultrasonic probe 14, a reception unit 20, a control unit 22, an operation unit 24, an information processing unit 26, and a display unit 42.

[0022] The information processing unit 26 may be configured with one or more processors that execute programs to realize the functions of the phasing addition unit 30, the B-mode image generation unit 32, the image processing unit 34, the Doppler processing unit 36, the Doppler waveform generation unit 38, and the color Doppler processing unit 40. The control unit 22 performs overall control over the ultrasound diagnostic apparatus 100. The operation unit 24 includes a keyboard, a mouse, a lever, buttons, a voice recognition device, etc., and outputs information regarding user operations to the control unit 22. The control unit 22 controls the ultrasound diagnostic apparatus 100 in accordance with operations on the operation unit 24.

[0023] The operation unit 24 may configure a user interface for operating the ultrasound diagnostic apparatus 100 together with the display unit 42. For example, the operation unit 24 may include a touch panel on the display screen of the display unit 42. The operation unit 24 may also have a function for operating a keyboard, lever, button, etc. that are virtually configured on the display screen. The control unit 22 may output information acquired via the user interface to the information processing unit 26.

[0024] An outline of the operation of the ultrasound diagnostic device 100 will be described. The ultrasound diagnostic device 100 transmits ultrasound from the ultrasound probe 14 to the subject 18, and receives the ultrasound reflected by the subject 18 at the ultrasound probe 14. The ultrasound diagnostic device 100 performs measurements in B mode, Doppler mode, and color Doppler mode.

[0025] In the B-mode operation, the ultrasound diagnostic device 100 generates B-mode image data based on the ultrasound received from the subject 18, and displays the B-mode image on the display unit 42. In the Doppler mode operation, the ultrasound diagnostic device 100 generates Doppler waveform data regarding blood flow based on the Doppler shift frequency of the ultrasound received from the subject 18, and displays the Doppler waveform on the display unit 42. In the color Doppler mode operation, the ultrasound diagnostic device 100 generates image data showing an image in which a color according to the blood flow velocity is applied to a B-mode image, and displays an image based on the image data on the display unit 42. Only one of the B-mode operation, the Doppler mode operation, and the color Doppler mode operation may be executed, or measurements using two or three of these three modes may be performed in a time-division manner.

[0026] A specific configuration of the ultrasound diagnostic device 100 and specific processing executed by the ultrasound diagnostic device 100 will be described. The ultrasound probe 14 is in contact with the surface of the subject 18. The ultrasound probe 14 includes a plurality of transducer elements 16. The transmission unit 12 outputs a transmission signal to each transducer element 16 of the ultrasound probe 14 under the control of the beam control unit 10. This causes ultrasound to be transmitted from the ultrasound probe 14. The beam control unit 10 controls the transmission unit 12 to form a transmission beam in the ultrasound probe 14, and scan the subject 18 with the transmission beam. That is, the transmission unit 12 adjusts the delay time or level of each transmission signal under the control of the beam control unit 10, forms a transmission beam in the ultrasound probe 14, and scans the subject 18 with the transmission beam.

[0027] When ultrasonic waves reflected within the subject 18 are received by each transducer element 16 of the ultrasonic probe 14, each transducer element 16 outputs an electrical signal corresponding to the received ultrasonic waves to the receiving unit 20. The receiving unit 20 performs processing such as amplification, detection, and frequency band limitation on the received signals output from each transducer element 16 under the control of the beam control unit 10, and outputs the received signals to the information processing unit 26. The information processing unit 26 performs processing on each received signal, which is executed by each component (phase adjustment and addition unit 30, B-mode image generation unit 32, image processing unit 34, Doppler processing unit 36, Doppler waveform generation unit 38, and color Doppler processing unit 40).

[0028] The phasing adder 30 performs phasing addition on the multiple reception signals output from the receiver 20 to the multiple transducer elements 16 to generate a phased reception signal. This generates a phased reception signal in which the phases of reception signals based on ultrasound received from a specific direction are adjusted and added so that they reinforce each other, and a reception beam is formed in that specific direction. The phasing adder 30 outputs the phased reception signal to the B-mode image generator 32 when operating in B mode. The phasing adder 30 also outputs the phased reception signal to the Doppler processor 36 when operating in Doppler mode, and outputs the phased reception signal to the color Doppler processor 40 when operating in color Doppler mode.

[0029] The operation in B mode will be described. The phasing addition unit 30 generates each phased receive signal based on the ultrasound received from each direction of the receive beam scanned inside the subject 18, and outputs it to the B-mode image generation unit 32. The B-mode image generation unit 32 generates B-mode image data based on the phased receive signals obtained for each receive beam direction, and outputs it to the image processing unit 34. The B-mode image data based on one scan of the transmit beam and receive beam (hereinafter referred to as the transmit and receive beam) is image data for one frame, and corresponds to one B-mode image.

[0030] The beam control unit 10, the transmission unit 12, the ultrasonic probe 14, the reception unit 20, the phasing addition unit 30, and the B-mode image generation unit 32 generate B-mode image data one after another while repeatedly scanning the transmission and reception beams, and output each B-mode image data to the image processing unit 34. The image processing unit 34 generates a video signal for displaying a B-mode image based on the B-mode image data, and outputs the video signal to the display unit 42. The display unit 42 displays the B-mode image based on the video signal.

[0031] The operation in the Doppler mode will be described. The Doppler mode includes a PW Doppler mode (pulsed wave Doppler mode) in which ultrasonic pulses are transmitted at a repetition frequency PRF, and a CW Doppler mode (continuous wave Doppler mode) in which ultrasonic waves are transmitted continuously. The user may select whether to operate in the PW Doppler mode or the CW Doppler mode.

[0032] The Doppler processing unit 36 ​​sequentially performs fast Fourier transform processing on the phased received signals divided into predetermined time lengths to generate frequency spectrum data of the Doppler shift frequency sequentially over time, and outputs the data to the Doppler waveform generating unit 38. Here, the Doppler shift frequency refers to a frequency that indicates the shift in frequency of the received signal relative to the frequency of the transmitted signal.

[0033] The Doppler waveform generating unit 38 generates Doppler waveform data based on a plurality of sets of frequency spectrum data that are sequentially output over time. An example of a Doppler waveform indicated by the Doppler waveform data is shown in FIG. 2. In the Doppler waveform, the horizontal axis represents time and the vertical axis represents the Doppler shift frequency. The Doppler shift frequency indicated on the vertical axis represents the blood flow velocity. The brightness of a plurality of pixels arranged vertically at a certain time on the time axis represents the frequency spectrum corresponding to that time. The baseline 52 extending linearly horizontally indicates that the Doppler shift frequency, i.e., the blood flow velocity, is zero.

[0034] The Doppler waveform generating unit 38 sequentially updates the Doppler waveform data over time. That is, the Doppler waveform generating unit 38 deletes the frequency spectrum data that was found earliest from the Doppler waveform data consisting of a series of frequency spectrum data, and adds the latest frequency spectrum data to the Doppler waveform data to update the Doppler waveform data. The image processing unit 34 generates a video signal that displays the Doppler waveform based on the Doppler waveform data, and outputs it to the display unit 42. The display unit 42 displays the Doppler waveform based on the video signal.

[0035] The operation in the color Doppler mode will be described. When the color Doppler processing unit 40 generates color Doppler data, ultrasonic waves are transmitted and received multiple times j times in each direction of the transmission and reception beam. The color Doppler processing unit 40 generates color Doppler data based on the phased reception signals acquired j times in each direction of the transmission and reception beam. The color Doppler data is data that indicates the blood flow velocity by color on a B-mode image of the area scanned by the transmission and reception beam. The color Doppler data may be data that, for example, adds blue to the area where blood flows in a direction away from the ultrasonic probe 14 and red to the area where blood flows in a direction toward the ultrasonic probe 14, and further increases the brightness of the area where the blood flow velocity is higher.

[0036] The color Doppler processing unit 40 obtains blood flow velocity v(r) in the depth direction of the transmit / receive beam based on the j types of phased received signals, for example, according to the autocorrelation processing shown in Patent Document 3. Here, v(r) indicates the blood flow velocity at the position of depth r. The color Doppler processing unit 40 generates color Doppler data based on the blood flow velocity v(r) in the depth direction at each depth r obtained for each direction of the transmit / receive beam, and outputs the color Doppler data to the image processing unit 34.

[0037] The image processing unit 34 generates data showing a B-mode color Doppler image in which a color according to the blood flow velocity is applied to the B-mode image based on the B-mode image data and the color Doppler data. The image processing unit 34 generates a video signal for displaying the B-mode color Doppler image based on the B-mode color Doppler image data, and outputs the video signal to the display unit 42. The display unit 42 displays the B-mode color Doppler image based on the video signal.

[0038] The image processing unit 34 may cause the display unit 42 to display the B-mode image and the Doppler waveform side by side. The image processing unit 34 may also cause the display unit 42 to display the B-mode color Doppler image and the Doppler waveform side by side.

[0039] 3 shows an example of a B-mode color Doppler image and a Doppler waveform displayed on the display unit 42. A B-mode color Doppler image is shown on the left, and a Doppler waveform is shown on the right. Each image was acquired near the mitral valve of the heart. The shaded area in the B-mode color Doppler image is the colored area.

[0040] A beam line 54 and a Doppler gate 56 indicating the direction of the transmit / receive beam in the Doppler mode are shown on the B-mode color Doppler image. Here, the Doppler gate 56 refers to a range in which blood flow velocity on the transmit / receive beam is measured, and is set in the image of blood vessels appearing in the B-mode image. The area sandwiched between two parallel lines intersecting the beam line 54 is the Doppler gate 56, and blood flow velocity is measured in this range. The beam line 54 and the Doppler gate 56 are set by the control unit 22 in response to the user's operation on the operation unit 24.

[0041] When the image processor 34 displays the Doppler waveform, the image processor 34 performs scaling. Scaling is a process that determines the ratio of the amplitude of the Doppler waveform to the vertical display range of the displayed image.

[0042] FIG. 4 shows a Doppler waveform for explaining scaling. The p-axis is defined as the vertical axis of the image coordinate system in the vertical direction of the displayed image. The coordinate value of the p-axis indicates the vertical position in the displayed image. The horizontal axis indicates time. The image processor 34 determines the display widths Vs for both positive and negative values ​​based on the value indicated by the Doppler waveform, as described below. The image processor 34 further associates the positive value Vs of the display width of the Doppler waveform with the upper limit value of the p-axis in the image coordinate system, and associates the negative value -Vs of the display width of the Doppler waveform with the lower limit value of the p-axis. This determines the display range of the Doppler waveform to be greater than -Vs and less than Vs.

[0043] The scaling performed by the image processor 34 will be specifically described. The image processor 34 obtains a Doppler waveform line E(t) based on the Doppler waveform data. The Doppler waveform line E(t) may be an envelope of the Doppler waveform. That is, the Doppler waveform line E(t) may be defined as a curve in which the component value of the frequency spectrum corresponding to each time is equal to or greater than a predetermined threshold on the negative side of the Doppler waveform line E(t) in a positive region above the baseline 52. Also, the Doppler waveform line E(t) may be defined as a curve in which the component value of the frequency spectrum corresponding to each time is equal to or greater than a predetermined threshold on the positive side of the Doppler waveform line E(t) in a negative region below the baseline 52. FIG. 4 shows the Doppler waveform together with the Doppler waveform line E(t).

[0044] The image processor 34 obtains a Doppler waveform average value in a time range going back from the current time to a predetermined N cardiac cycles, where N is a positive integer. The cardiac cycle may be measured by a pulsation signal output from a pulsation detector 70 that detects the heartbeat of the subject 18. The pulsation detector 70 may be, for example, an electrocardiogram device. The pulsation signal may be a signal indicating an electrocardiogram. The Doppler waveform average value may be defined as a value obtained by averaging the midpoint value (half the value obtained by adding the upper limit value and the lower limit value) of the blood flow velocity range in which the component value of the frequency spectrum is equal to or greater than a predetermined threshold value in a time range going back from the current time to a predetermined N cardiac cycles. The image processor 34 sets the Doppler waveform average value as a reference value V0. The image processor 34 also obtains a maximum value Vp and a minimum value Vn of the Doppler waveform line E(t) in a time range going back from the current time to N cardiac cycles. The image processor 34 may obtain the maximum value Vp, the minimum value Vn, and the average value of the Doppler waveform in a time range going back a predetermined time from the present time.

[0045] The image processor 34 determines the greater of the absolute value |Vp-V0| obtained by subtracting the reference value V0 from the maximum value Vp, and the absolute value |Vn-V0| obtained by subtracting the reference value V0 from the minimum value Vn, as the amplitude SW. That is, the image processor 34 determines the amplitude SW according to SW=max(|Vp-V0|, |Vn-V0|). Here, "max" indicates the maximum value among the values ​​listed in the following parentheses.

[0046] The image processing unit 34 multiplies the swing width SW by a predetermined scale factor k to obtain the display width Vs as Vs = k·SW. The image processing unit 34 associates a positive value +Vs of the display width with the upper limit value Smax of the display range of the p-axis of the image coordinate system, and associates a negative value -Vs of the display width with the lower limit value -Smax of the display range of the p-axis of the image coordinate system. The image processing unit 34 also associates a reference value V0 with the center value S0 of the display range of the p-axis.

[0047] Image processing unit 34 converts the values ​​indicated by the Doppler waveform into p-axis coordinate values ​​so that the upper end of the displayed image indicates +Vs, the lower end of the displayed image indicates -Vs, and further so that the center position of the vertical display range indicates reference value V0. Image processing unit 34 generates a video signal displaying the Doppler waveform based on the Doppler waveform data obtained by converting the values ​​indicated by the Doppler waveform into p-axis coordinate values, and outputs the video signal to display unit 42. Display unit 42 displays an image showing the Doppler waveform based on the video signal.

[0048] The scale factor k may be determined in advance based on the results of past diagnoses, etc. The scale factor k may be read in via a user interface. That is, the image processor 34 may acquire the scale factor k via the user interface and the controller 22. When observing the vicinity of the mitral valve, the scale factor k may be, for example, equal to or greater than 1.1 and less than 1.8.

[0049] In the example shown in FIG. 4, the swing width SW=max(|Vp-V0|, |Vn-V0|) is SW=|Vn-V0|, -Vs=-|Vn-V0| corresponds to the lower limit value of the p axis, and +Vs=|Vn-V0| corresponds to the upper limit value of the p axis.

[0050] The scale factor k may be determined based on an n-th degree polynomial as a scale function, as shown in the following (Equation 1).

[0051] (Math 1)k=α(n)x n +α(n-1)x n-1 +···· +α(1)x+α(0)

[0052] Here, the index value x is a value indicating the difference between the maximum value Vp and the minimum value Vn, and is defined by the following (Equation 2).

[0053] (Math 2)x=|Vp-Vn| / max(|Vp|,|Vn|)

[0054] The n+1 coefficients α(0) to α(n) are calculated as follows. First, the user sets n+1 set points on an xk coordinate plane with k as the vertical axis and x as the horizontal axis. Then, the coefficients α(0) to α(n) are calculated so that the curve indicated by the scale function is a curve passing through the n+1 set points, or is approximated to a curve passing through the n+1 set points. The coefficients α(0) to α(n) may be calculated according to the least squares method, spline interpolation, or the like. The user may set the set points via a user interface constituted by the operation unit 24 and the display unit 42.

[0055] An example of a scale function is shown in Fig. 5. This scale function is obtained by specifying six set points on the xk coordinate plane by the user and finding each coefficient of a fifth-order polynomial that complements the six set points. Specifically, the scale function shown in Fig. 5 is expressed as (Equation 3) with n=5, α(0)=9, α(1)=-20.936, α(2)=17.829, α(3)=-2.7052, α(4)=-2.897, and α(5)=0.9594.

[0056] (Math 3)k=0.9594x 5 -2.897x 4 -2.7052x 3 +17.829x 2 -20.936x+9

[0057] Waveform characteristic values ​​such as the maximum value, minimum value, and average value of the Doppler waveform vary depending on the observation site. Therefore, if the Doppler waveform is displayed at a constant scale, it may be difficult to see the Doppler waveform. According to the process of finding the scale factor k based on the scale function, the scale factor k is found by providing the scale function with an index value x based on the maximum value Vp of the Doppler waveform line E(t) and the minimum value Vn of the Doppler waveform line E(t). As a result, even if the maximum value Vp of the Doppler waveform line E(t) and the minimum value Vn of the Doppler waveform line E(t) change in response to a change in the observation site, an appropriate scale factor k can be found.

[0058] In this manner, the information processing unit 26 obtains the index value x by dividing the absolute value of the value obtained by subtracting the minimum value Vn of the Doppler waveform line E(t) from the maximum value Vp of the Doppler waveform line E(t) by the greater of the absolute value of the maximum value Vp and the absolute value of the minimum value Vn, as shown in (Equation 2). The information processing unit 26 further determines the scale factor k by applying the index value x to the scale function shown in (Equation 1).

[0059] The information processing unit 26 determines the display range by multiplying the greater of the absolute value of the value obtained by subtracting the reference value V0 from the maximum value Vp of the Doppler waveform line E(t) and the absolute value of the value obtained by subtracting the reference value V0 from the minimum value Vn of the Doppler waveform line E(t) by a scale factor k. That is, the information processing unit 26 obtains the amplitude SW according to SW=max(|Vp-V0|, |Vn-V0|) and determines the range from -k·SW to k·SW as the display range of the Doppler waveform.

[0060] The left side of FIG. 6 shows an example of a B-mode color Doppler image acquired near the abdominal aorta. The right side of FIG. 6 shows a Doppler waveform acquired near the abdominal aorta. FIG. 7 also shows a Doppler waveform line E(t) along with the Doppler waveform. Unlike the vicinity of the mitral valve of the heart, the direction of blood flow near the abdominal aorta is unidirectional. In the example shown in FIG. 7, the reference value V0 is on the positive side of the baseline 52, and the amplitude SW is SW=max(|Vp-V0|, |Vn-V0|)=Vp-V0. The image processor 34 multiplies the amplitude SW by the scale factor k to obtain the display width Vs as Vs=k·SW. When observing the vicinity of the abdominal aorta, the scale factor k may be, for example, 1.8 or more and less than 3.2.

[0061] The left side of FIG. 8 shows an example of a B-mode color Doppler image acquired near the portal vein of the liver. The right side of FIG. 8 shows a Doppler waveform acquired near the portal vein. FIG. 9 also shows a Doppler waveform line E(t) along with the Doppler waveform. Unlike the vicinity of the mitral valve of the heart, the direction of blood flow near the portal vein is unidirectional. In the example shown in FIG. 9, the reference value V0 is more negative than the baseline 52, and the amplitude SW is SW=max(|Vp-V0|, |Vn-V0|)=V0-Vn. The image processor 34 multiplies the amplitude SW by the scale factor k to obtain the display width Vs as Vs=k·SW. When observing the vicinity of the portal vein, the scale factor k may be, for example, 2.4 or more and less than 9.0.

[0062] The image processor 34 may determine the scale factor k based on the area between the Doppler waveform line E(t) and a reference line indicating the reference value V0. The image processor 34 obtains a time integral value of |Et(t)-V0|, for example, in a time range going back a predetermined N cardiac cycles from the current time, or in a time range going back a predetermined time from the current time. The image processor 34 may increase the scale factor k as the time integral value decreases. The image processor 34 may determine the scale factor k so that the proportion R of the area sandwiched between the k times Doppler waveform line E(t) and the reference line occupying the displayed image is equal to or greater than a certain threshold value Th1 and equal to or less than a certain threshold value Th2 (Th1≦R≦Th2).

[0063] In the above, an embodiment has been shown in which the reference value V0 is the Doppler waveform average value. The reference value V0 may be 0 or the center of gravity of the Doppler waveform. The center of gravity of the Doppler waveform is defined, for example, as a value obtained by calculating a weighted average value of blood flow velocity for each time period using the component values ​​of the frequency spectrum as weighting values, and averaging the weighted average value of blood flow velocity in a time range going back from the current time to a predetermined N cardiac cycles. The center of gravity of the Doppler waveform may also be defined as a value obtained by averaging the weighted average value of blood flow velocity in a time range going back from the current time period by a predetermined time.

[0064] The image processing unit 34 may update the scale factor k at a timing according to the pulsation of the subject 18. For example, the image processing unit 34 may update the scale factor k every M cardiac cycles, where M is a positive integer. Fig. 10 conceptually shows a Doppler waveform 60 and an update timing 58 of the scale factor k in a case where the scale factor k is updated every M cardiac cycles. Furthermore, the image processing unit 34 may update the scale factor k every update cycle T, where T is the update cycle. Fig. 11 conceptually shows a Doppler waveform 60 and an update timing 58 of the scale factor k in a case where the scale factor k is updated every update cycle T.

[0065] Furthermore, the image processing unit 34 may update the scale factor k when an operation for updating the scale factor k is performed on the operation unit 24.

[0066] The image processor 34 may automatically set the scale factor k according to the diagnostic situation. The diagnostic situation is specified by, for example, an observation site such as the heart, liver, or abdomen, and a lesion that may be found in each observation site. The diagnostic situation may be recognized by the image processor 34 via a user interface.

[0067] When the Doppler mode is the PW Doppler mode, the control unit 22 may adjust the repetition frequency PRF so that aliasing does not occur on the display image. Here, the aliasing phenomenon refers to the Doppler waveform being periodically repeated and displayed in the vertical axis direction. When the scale factor k is increased, the control unit 22 may control the beam control unit 10, the transmission unit 12, the reception unit 20, and the information processing unit 26 so that the repetition frequency PRF becomes high enough to avoid the aliasing phenomenon. When the scale factor k is decreased, the control unit 22 may control the beam control unit 10, the transmission unit 12, the reception unit 20, and the information processing unit 26 so that the repetition frequency PRF becomes low. By lowering the repetition frequency PRF, the display resolution in the vertical axis direction is improved.

[0068] [Configuration of the present invention] Configuration 1: a transmitter that transmits ultrasonic waves to a subject using an ultrasonic probe; a receiving unit that receives the ultrasonic waves reflected by the subject by the ultrasonic probe; An information processing unit that processes a received signal output from the receiving unit, The information processing unit includes: generating Doppler waveform data based on the received signals; determining a maximum value, a minimum value and a reference value of a Doppler waveform line obtained from the Doppler waveform data; an ultrasonic diagnostic apparatus that determines a display range of blood flow velocity indicated by a Doppler waveform based on the maximum value, the minimum value, and the reference value; Configuration 2: 2. The ultrasound diagnostic apparatus according to claim 1, The ultrasonic diagnostic apparatus according to claim 1, wherein the reference value is a Doppler waveform average value, 0, or a center of gravity. Configuration 3: The ultrasound diagnostic apparatus according to configuration 1 or 2, The information processing unit includes: the display range is determined by multiplying the greater of the absolute value of a value obtained by subtracting the reference value from the maximum value and the absolute value of a value obtained by subtracting the reference value from the minimum value by a predetermined scale factor. Configuration 4: 4. The ultrasound diagnostic apparatus according to claim 3, an index value obtained by dividing an absolute value of a value obtained by subtracting the minimum value from the maximum value by the greater of the absolute value of the maximum value and the absolute value of the minimum value, wherein the scale factor is determined according to the index value obtained by dividing the absolute value of the maximum value and the absolute value of the minimum value. Configuration 5: 4. The ultrasound diagnostic apparatus according to claim 3, The information processing unit includes: a scale function for obtaining the scale factor by providing an index value, the scale factor being calculated according to a value of the scale function representing a curve passing through a plurality of set points or a curve approximated to the curve passing through a plurality of the set points; The index value is a value indicating the difference between the maximum value and the minimum value, The set point is The ultrasonic diagnostic apparatus is characterized in that the index value and the scale factor are associated with each other on a coordinate plane. Configuration 6 6. The ultrasound diagnostic apparatus according to claim 5, The information processing unit includes: An ultrasonic diagnostic apparatus, comprising: a user interface for setting the set points. Configuration 7: 4. The ultrasound diagnostic apparatus according to claim 3, The information processing unit includes: An ultrasonic diagnostic apparatus comprising: an ultrasonic diagnostic device which determines the scale factor in accordance with a diagnostic situation. Configuration 8: 4. The ultrasound diagnostic apparatus according to claim 3, The ultrasonic diagnostic apparatus according to claim 1, wherein the information processing unit acquires the scale factor via a user interface. Configuration 9: An ultrasonic diagnostic apparatus according to any one of configurations 1 to 8, The information processing unit includes: acquiring a signal indicating the pulsation of the subject from a pulsation detection device that detects the pulsation of the subject; 4. An ultrasonic diagnostic apparatus comprising: an ultrasonic diagnostic device that determines the display range at a timing according to the pulsation of the subject; Configuration 10: 10. The ultrasonic diagnostic device according to any one of configurations 1 to 9, wherein a repetition frequency when the transmitting unit transmits the ultrasonic waves is set in accordance with the display range. Configuration 11: The ultrasonic diagnostic apparatus according to any one of configurations 1 to 10, The information processing unit includes: an ultrasonic diagnostic apparatus that determines the display range in accordance with an area between the Doppler waveform line and a reference line indicated by the reference value; [Explanation of symbols]

[0069] 10 beam control unit, 12 transmission unit, 14 ultrasound probe, 16 vibration element, 18 subject, 20 reception unit, 22 control unit, 24 operation unit, 26 information processing unit, 30 phasing addition unit, 32 B-mode image generation unit, 34 image processing unit, 36 Doppler processing unit, 38 Doppler waveform generation unit, 40 color Doppler processing unit, 42 display unit, 52 baseline, 54 beam straight line, 56 Doppler gate, 58 update timing, 60 Doppler waveform, 70 pulse detection device, 100 ultrasound diagnostic device.

Claims

1. a transmitter that transmits ultrasonic waves to a subject using an ultrasonic probe; a receiving unit that receives the ultrasonic waves reflected by the subject by the ultrasonic probe; An information processing unit that processes a received signal output from the receiving unit, The information processing unit includes: generating Doppler waveform data based on the received signals; determining a maximum value, a minimum value and a reference value of a Doppler waveform line obtained from the Doppler waveform data; an ultrasonic diagnostic apparatus that determines a display range of blood flow velocity indicated by a Doppler waveform based on the maximum value, the minimum value, and the reference value;

2. 2. The ultrasonic diagnostic apparatus according to claim 1, The ultrasonic diagnostic apparatus according to claim 1, wherein the reference value is a Doppler waveform average value, 0, or a center of gravity.

3. 2. The ultrasonic diagnostic apparatus according to claim 1, The information processing unit includes: the display range is determined by multiplying the greater of the absolute value of a value obtained by subtracting the reference value from the maximum value and the absolute value of a value obtained by subtracting the reference value from the minimum value by a predetermined scale factor.

4. The ultrasonic diagnostic apparatus according to claim 3, an index value obtained by dividing an absolute value of a value obtained by subtracting the minimum value from the maximum value by the greater of the absolute value of the maximum value and the absolute value of the minimum value, wherein the scale factor is determined according to the index value obtained by dividing the absolute value of the maximum value and the absolute value of the minimum value.

5. 4. The ultrasonic diagnostic apparatus according to claim 3, The information processing unit includes: a scale function for obtaining the scale factor by providing an index value, the scale factor being calculated according to a value of the scale function representing a curve passing through a plurality of set points or a curve approximated to the curve passing through a plurality of the set points; The index value is a value indicating the difference between the maximum value and the minimum value, The set point is The ultrasonic diagnostic apparatus is characterized in that the index value and the scale factor are associated with each other on a coordinate plane.

6. 6. The ultrasonic diagnostic apparatus according to claim 5, The information processing unit includes: An ultrasonic diagnostic apparatus, comprising: a user interface for setting the set points.

7. The ultrasonic diagnostic apparatus according to claim 3, The information processing unit includes: An ultrasonic diagnostic apparatus comprising: an ultrasonic diagnostic device which determines the scale factor in accordance with a diagnostic situation.

8. The ultrasonic diagnostic apparatus according to claim 3, The ultrasonic diagnostic apparatus according to claim 1, wherein the information processing unit acquires the scale factor via a user interface.

9. The ultrasonic diagnostic apparatus according to any one of claims 1 to 8, The information processing unit includes: acquiring a signal indicating the pulsation of the subject from a pulsation detection device that detects the pulsation of the subject; 4. An ultrasonic diagnostic apparatus comprising: an ultrasonic diagnostic device that determines the display range at a timing according to the pulsation of the subject;

10. 9. The ultrasonic diagnostic apparatus according to claim 1, further comprising: a repetition frequency at which the transmitting unit transmits the ultrasonic waves in accordance with the display range.

11. The ultrasonic diagnostic apparatus according to any one of claims 1 to 8, The information processing unit includes: an ultrasonic diagnostic apparatus that determines the display range in accordance with an area between the Doppler waveform line and a reference line indicated by the reference value;

Images