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, determines whether an observation site is an artery or a vein based on the Doppler waveform data, and determines a display range of a blood flow rate shown by a Doppler waveform, in accordance with a determination result.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Ultrasound diagnostic devices that observe a subject by transmitting and receiving ultrasound waves are widely used. Ultrasound diagnostic devices generally have the function of displaying a Doppler waveform, which indicates blood flow velocity. Waveform characteristics such as the maximum, minimum, and average values ​​of the Doppler waveform vary depending on the observed region. Therefore, technologies have been developed that adjust 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 the statistical value of 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 calculating the multiples of the baseline and the estimated upper and lower limits of the velocity range to set in the display range based on the maximum positive value and the maximum negative value.

[0004] Patent Document 2 describes an ultrasound color Doppler imaging system that determines whether a blood vessel to be diagnosed is an artery or a vein based on the pulsatility index PI and resistivity 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] Japanese Patent Application Laid-Open No. 2010-88943 [Patent Document 2] Japanese Patent Application Publication No. 11-235342 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-87302 Summary of the Invention [Problem to be solved by the invention]

[0006] The waveform characteristics of the Doppler waveform vary depending on the area being observed. Therefore, if the Doppler waveform is displayed at a fixed scale, it may be difficult to see the Doppler waveform.

[0007] An object of the present invention is to set the display state of the Doppler waveform so that the Doppler waveform is easy to see. [Means for solving the problem]

[0008] The present invention comprises a transmitting unit that transmits ultrasound waves to a subject using an ultrasound probe, a receiving unit that receives the ultrasound waves reflected by the subject using the ultrasound probe, and an information processing unit that processes a received signal output from the receiving unit, wherein the information processing unit generates Doppler waveform data based on the received signal, determines whether the observed region is an artery or a vein based on the Doppler waveform data, and determines a display range of the blood flow velocity indicated by the Doppler waveform depending on the determination result.

[0009] The present invention also includes a transmitting unit that transmits ultrasonic waves to a subject using an ultrasonic probe, a receiving unit that receives the ultrasonic waves reflected by the subject using the ultrasonic probe, and an information processing unit that processes received signals output from the receiving unit, wherein the information processing unit generates Doppler waveform data based on the received signals, determines whether the observed site is an artery or a vein based on the degree of variation in Doppler frequency of multiple received signals obtained based on multiple transmissions and receptions of ultrasonic waves, and determines a display range of the blood flow velocity indicated by the Doppler waveform depending on the determination result.

[0010] The present invention also includes a transmitting unit that transmits ultrasonic waves to a subject using an ultrasonic probe, a receiving unit that receives the ultrasonic waves reflected by the subject using the ultrasonic probe, and an information processing unit that processes a received signal output from the receiving unit, wherein the information processing unit generates Doppler waveform data and color Doppler data based on the received signal, determines whether the observed region is an artery or a vein based on the color Doppler data, and determines a display range of the blood flow velocity indicated by the Doppler waveform depending on the determination result.

[0011] Preferably, the information processing unit determines whether the observation site is an artery or a vein depending on whether aliasing occurs in the color Doppler data.

[0012] Preferably, the information processing unit determines a scale factor for displaying the Doppler waveform in accordance with the determination result.

[0013] Preferably, the information processing unit determines a reference value of the Doppler waveform line obtained from the Doppler waveform data, and determines the scale factor in accordance with the determination result as well as the area of ​​the region between the Doppler waveform line obtained from the Doppler waveform data and the reference line indicated by the reference value.

[0014] Preferably, the information processing unit obtains a maximum value, a minimum value, and a reference value of the Doppler waveform line from the Doppler waveform data, and determines the scale factor based on the maximum value, the minimum value, and the reference value in addition to the judgment result.

[0015] Preferably, the information processing unit determines whether the observation site is an artery or a vein based on a time differential value of a Doppler waveform line calculated from the Doppler waveform data.

[0016] Preferably, the information processing unit determines whether the observation site is an artery or a vein based on a time integral value of a Doppler waveform line obtained from the Doppler waveform data.

[0017] Preferably, the information processing unit determines whether the observation site is an artery or a vein depending on whether aliasing occurs in the Doppler waveform data.

[0018] Preferably, a pulse detection device for detecting the pulse of the subject is provided, and the information processing unit determines whether the observation site is an artery or a vein at a timing according to the pulse of the subject.

[0019] Preferably, the repetition frequency at which the transmitting unit transmits the ultrasonic waves is set in accordance with the display range. [Effects of the Invention]

[0020] According to the present invention, the display state of the Doppler waveform can be set so that the Doppler waveform is easy to see. [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a diagram illustrating the configuration of an ultrasound diagnostic apparatus. [Figure 2] FIG. 10 is a diagram showing an example of a Doppler waveform. [Figure 3] 1A and 1B are diagrams showing examples of a B-mode color Doppler image and a Doppler waveform. [Figure 4] FIG. 10 shows a Doppler waveform line along with a Doppler waveform. [Figure 5] FIG. 10 is a diagram showing a Doppler waveform line E(t) and the polarity of its time derivative. [Figure 6] FIG. 10 is a diagram showing a Doppler waveform line and an evaluation area. [Figure 7] 1A and 1B are diagrams showing examples of a B-mode color Doppler image and a Doppler waveform. [Figure 8] FIG. 10 shows a Doppler waveform line along with a Doppler waveform. [Figure 9] 1A and 1B are diagrams showing examples of a B-mode color Doppler image and a Doppler waveform. [Figure 10] FIG. 10 shows a Doppler waveform line along with a Doppler waveform. [Figure 11]FIG. 10 is a diagram illustrating the update timing of the scale factor. [Figure 12] FIG. 10 is a diagram illustrating the update timing of the scale factor. DETAILED DESCRIPTION OF THE INVENTION

[0022] Each embodiment of the present invention will be described with reference to the drawings. Identical components shown in multiple drawings are designated by the same reference numerals, and their description will be omitted. FIG. 1 shows the configuration of an ultrasound diagnostic device 100 according to an embodiment of the present invention. The ultrasound diagnostic device 100 includes a beam control unit 10, a transmission unit 12, an ultrasound probe 14, a reception unit 20, a control unit 22, an operation unit 24, an information processing unit 26, and a display unit 42.

[0023] The information processing unit 26 may be configured with one or more processors that execute programs to implement the functions of the phasing 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. The control unit 22 performs overall control of 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 related to 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.

[0024] The operation unit 24 may constitute 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. Information acquired via the user interface may be output by the control unit 22 to the information processing unit 26.

[0025] An outline of the operation of the ultrasound diagnostic device 100 will be described. The ultrasound diagnostic device 100 transmits ultrasound waves from the ultrasound probe 14 to the subject 18, and receives the ultrasound waves reflected by the subject 18 with the ultrasound probe 14. The ultrasound diagnostic device 100 performs measurements in B-mode, Doppler mode, and color Doppler mode.

[0026] In B-mode operation, the ultrasound diagnostic device 100 generates B-mode image data based on ultrasound waves received from the subject 18 and displays the B-mode image on the display unit 42. In Doppler mode operation, the ultrasound diagnostic device 100 generates Doppler waveform data regarding blood flow based on the Doppler shift frequency of the ultrasound waves received from the subject 18 and displays the Doppler waveform on the display unit 42. In color Doppler mode operation, the ultrasound diagnostic device 100 generates image data representing an image in which a color corresponding to the blood flow velocity is added 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, Doppler mode operation, and color Doppler mode operation may be performed, or measurements using two or three of these three modes may be performed in a time-division manner.

[0027] The specific configuration of the ultrasound diagnostic device 100 and the 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 transmitter 12 outputs a transmission signal to each transducer element 16 of the ultrasound probe 14 under the control of the beam controller 10. This causes ultrasound waves to be transmitted from the ultrasound probe 14. The beam controller 10 controls the transmitter 12 to form a transmission beam in the ultrasound probe 14, and scan the subject 18 with the transmission beam. That is, the transmitter 12 adjusts the delay time or level of each transmission signal under the control of the beam controller 10, forms a transmission beam in the ultrasound probe 14, and scans the subject 18 with the transmission beam.

[0028] 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, under the control of the beam control unit 10, performs processing such as amplification, detection, and frequency band limitation on the received signals output from each transducer element 16, and outputs the results to the information processing unit 26. The information processing unit 26 performs processing on each received signal, which is executed by each component (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).

[0029] The phasing adder 30 phases and adds the multiple received signals output from the receiver 20 to the multiple transducer elements 16 to generate phased received signals. As a result, phased received signals are generated in which the phases of received signals based on ultrasound received from a specific direction are adjusted and added so that they reinforce each other, and a receive beam is formed in that specific direction. When operating in B mode, the phasing adder 30 outputs the phased received signals to the B-mode image generator 32. When operating in Doppler mode, the phasing adder 30 outputs the phased received signals to the Doppler processor 36, and when operating in color Doppler mode, it outputs the phased received signals to the color Doppler processor 40.

[0030] The operation in B mode will now be described. The phasing adder 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 generator 32. The B-mode image generator 32 generates B-mode image data based on the phased receive signals obtained for each receive beam direction, and outputs it to the image processor 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 one frame of image data, and corresponds to one B-mode image.

[0031] The beam control unit 10, transmission unit 12, ultrasound probe 14, reception unit 20, phasing addition unit 30, and B-mode image generation unit 32 successively generate B-mode image data 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.

[0032] Operation in Doppler mode will be described. Doppler modes include PW Doppler mode (pulsed wave Doppler mode), in which ultrasonic pulses are transmitted at a repetition frequency PRF, and CW Doppler mode (continuous wave Doppler mode), in which ultrasonic waves are transmitted continuously. Whether to operate in PW Doppler mode or CW Doppler mode may be selected by user operation.

[0033] The Doppler processing unit 36 ​​sequentially performs fast Fourier transform processing on the phased received signals divided into predetermined time lengths to sequentially generate frequency spectrum data of Doppler shift frequencies over time and output the data to the Doppler waveform generating unit 38. Here, the Doppler shift frequency refers to a frequency that indicates the deviation of the frequency of the received signal from the frequency of the transmitted signal.

[0034] The Doppler waveform generator 38 generates Doppler waveform data based on multiple sets of frequency spectrum data that are sequentially output over time. Figure 2 shows an example of a Doppler waveform represented by Doppler waveform data. The Doppler waveform has time on the horizontal axis and Doppler shift frequency on the vertical axis. The Doppler shift frequency shown on the vertical axis indicates blood flow velocity. The brightness of multiple pixels arranged vertically at a given time on the time axis indicates the frequency spectrum corresponding to that time. The baseline 52 extending linearly horizontally indicates that the Doppler shift frequency, i.e., blood flow velocity, is zero.

[0035] The Doppler waveform generation unit 38 sequentially updates the Doppler waveform data over time. That is, the Doppler waveform generation unit 38 deletes the earliest frequency spectrum data from the Doppler waveform data, which is made up of a series of frequency spectrum data, and adds the most recent frequency spectrum data to the Doppler waveform data to update the Doppler waveform data. The image processing unit 34 generates a video signal displaying 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.

[0036] Operation in color Doppler mode will now 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 transmit and receive beams. Here, J is an integer equal to or greater than 2. The color Doppler processing unit 40 generates color Doppler data based on phased received signals acquired J times in each direction of the transmit and receive beams. The color Doppler data is data that indicates blood flow velocity by color on a B-mode image of the area scanned by the transmit and receive beams. The color Doppler data may be data that, for example, indicates blue in areas where blood flows away from the ultrasound probe 14 and red in areas where blood flows toward the ultrasound probe 14, and further indicates that the brightness increases as the blood flow velocity increases in areas.

[0037] The color Doppler processing unit 40 calculates the blood flow velocity v(r) in the depth direction of the transmit / receive beam based on the multiple J phased receive signals, for example, according to the autocorrelation processing disclosed 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 calculated for each direction of the transmit / receive beam, and outputs the data to the image processing unit 34. The specific process for calculating the blood flow velocity v(r) will be described below.

[0038] The phased received signal acquired at the qth (q=1 to J) of the first to Jth signals is expressed by the following (Equation 1).

[0039]

number

[0040] r is the coordinate value in the depth direction. I(r,q) indicates the in-phase component of the phased received signal, and Q(r,q) indicates the quadrature component of the phased received signal. j is the imaginary unit. The color Doppler processing unit 40 calculates the autocorrelation value A(r) for J phased received signals z(r,1), z(r,2), ...z(r,J) according to (Equation 2).

[0041]

number

[0042] Here, the superscript "*" indicates a conjugate complex number. The color Doppler processor 40 calculates the blood flow velocity v(r) according to Equation 3 using the real part Re[A(r)] and the imaginary part Im[A(r)] of the autocorrelation value A(r).

[0043]

number

[0044] where c is the propagation velocity of the ultrasound propagating within the subject 18, and f0 is the frequency of the ultrasound transmitted and received by the ultrasound probe 14. The part of the right side of (Equation 3) to the right of c / (2f0) represents the Doppler frequency. The blood flow velocity v(r) represents the depth component of the blood flow velocity at depth r. If the angle φ that the blood flow direction makes with the depth direction is known, then v(r) / cosφ is the blood flow velocity.

[0045] When it is not necessary to obtain an absolute value of the blood flow velocity (for example, a value in the MKSA unit system), such as when measuring a blood flow velocity distribution, the blood flow velocity may be a value obtained by multiplying the value obtained by (Equation 3) by an arbitrary constant. Also, instead of the blood flow velocity, a Doppler shift frequency measurement value, which is the part on the right side of (Equation 3) to the right of c / (2f0), may be used.

[0046] Based on the B-mode image data and the color Doppler data, 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 color Doppler image data, the image processing unit 34 generates a video signal for displaying the B-mode color Doppler image 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.

[0047] The image processing unit 34 may display the B-mode image and the Doppler waveform side by side on the display unit 42. The image processing unit 34 may also display the B-mode color Doppler image and the Doppler waveform side by side on the display unit 42.

[0048] FIG. 3 shows an example of a B-mode color Doppler image and a Doppler waveform displayed on the display unit 42. The B-mode color Doppler image is shown on the left, and the 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.

[0049] A beam line 54 and a Doppler gate 56 indicating the direction of the transmit / receive beam in Doppler mode are shown on the B-mode color Doppler image. Here, the Doppler gate 56 refers to the range on the transmit / receive beam where blood flow velocity is measured, and is set in the image of the blood vessels that appear in the B-mode image. The area sandwiched between two parallel lines that intersect with the beam line 54 is the Doppler gate 56, and blood flow velocity is measured within this range. The beam line 54 and the Doppler gate 56 are set by the control unit 22 in response to user operation of the operation unit 24.

[0050] When the image processing unit 34 displays the Doppler waveform, the image processing unit 34 performs scaling. Scaling is a process that determines the ratio of the amplitude of the Doppler waveform to the display range in the vertical axis direction of the displayed image.

[0051] FIG. 4 shows a Doppler waveform to explain scaling. The vertical direction of the displayed image is defined as the p-axis, which is the vertical axis of the image coordinate system. The coordinate value of the p-axis indicates the vertical position in the displayed image. The horizontal axis indicates time. The image processing unit 34 calculates the display width Vs for both positive and negative values ​​based on the value indicated by the Doppler waveform, as described below. The image processing unit 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 blood flow velocity indicated by the Doppler waveform to be greater than or equal to -Vs and less than or equal to Vs.

[0052] The scaling performed by the image processing unit 34 will be described in detail. The image processing unit 34 determines a Doppler waveform line E(t) based on the Doppler waveform data. The Doppler waveform line E(t) may be the envelope of the Doppler waveform. That is, the Doppler waveform line E(t) may be defined as a curve in which, in a positive region above the baseline 52, the component values ​​of the frequency spectrum corresponding to each time are equal to or greater than a predetermined threshold on the negative side of the Doppler waveform line E(t). Also, in a negative region below the baseline 52, the Doppler waveform line E(t) may be defined as a curve in which the component values ​​of the frequency spectrum corresponding to each time are equal to or greater than a predetermined threshold on the positive side of the Doppler waveform line E(t). FIG. 4 shows the Doppler waveform and the Doppler waveform line E(t).

[0053] The image processing unit 34 calculates the Doppler waveform average value over a time range extending back N cardiac cycles from the current time, where N is a positive integer. The cardiac cycle may be measured using a pulse signal output from a pulse detection device 70 that detects the heartbeat of the subject 18. The pulse detection device 70 may be, for example, an electrocardiogram device. The pulse signal may be a signal representing an electrocardiogram. The Doppler waveform average value may be defined as the average value of the midpoint of the blood flow velocity range in which the component value of the frequency spectrum is equal to or greater than a predetermined threshold (half the sum of the upper and lower limits) over a time range extending back N cardiac cycles from the current time. The image processing unit 34 sets the Doppler waveform average value as a reference value V0. The image processing unit 34 also calculates the maximum value Vp and minimum value Vn of the Doppler waveform line E(t) over a time range extending back N cardiac cycles from the current time. The image processor 34 may also obtain the maximum value Vp, the minimum value Vn, and the average value of the Doppler waveform within a time range going back a predetermined time from the present time.

[0054] The image processing unit 34 determines the amplitude SW as the greater of the absolute value |Vp-V0| of the value obtained by subtracting the reference value V0 from the maximum value Vp, or the absolute value |Vn-V0| of the value obtained by subtracting the reference value V0 from the minimum value Vn. That is, the image processing unit 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 parentheses that follow it.

[0055] 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.

[0056] Image processing unit 34 converts the values ​​indicated by the Doppler waveform into p-axis coordinate values ​​so that the top edge of the displayed image indicates +Vs, the bottom edge of the displayed image indicates -Vs, and 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.

[0057] The scale factor k may be determined in advance based on the results of previous diagnoses, etc. The scale factor k may be read via a user interface. That is, the image processing unit 34 may acquire the scale factor k via the user interface and the control unit 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.

[0058] 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.

[0059] The image processing unit 34 may perform a blood vessel determination to determine whether the observation site is an artery or a vein, and determine the scale factor k according to the determination result. In this embodiment, the image processing unit 34 sets the scale factor k=ka when the observation site is determined to be an artery to be larger than the scale factor k=kv when the observation site is determined to be a vein.

[0060] Generally, when observing veins, large noise appears in the Doppler waveform image. Therefore, if the scale factor k is increased, the noise is emphasized, and the image displayed may make it difficult to grasp the approximate shape of the Doppler waveform or the direction of blood flow. On the other hand, when observing arteries, the Doppler waveform has a large amplitude, and the magnitude of the blood flow velocity indicated by the Doppler waveform is sufficiently large compared to the noise. Furthermore, since the shape of the Doppler waveform is generally observed in detail for arteries, increasing the scale factor k can make it easier to grasp the detailed shape of the Doppler waveform on the image.

[0061] In the ultrasound diagnostic device 100 according to this embodiment, the scale factor ka when the observation site is determined to be an artery is set larger than the scale factor kv when the observation site is determined to be a vein. Therefore, when observing a vein, an image is displayed that makes it easy to grasp the general shape of the Doppler waveform and the direction of blood flow, and when observing an artery, an image is displayed that makes it easy to grasp the detailed shape of the Doppler waveform on the image.

[0062] A specific example of blood vessel determination performed by the image processor 34 will be described. Blood vessel determination may be performed based on the polarity of the time derivative of the Doppler waveform. FIG. 5 shows the polarity of the Doppler waveform E(t) and its time derivative dE(t) / dt. The image processor 34 stores, for each of arteries and veins, a pattern in which the polarity of the Doppler waveform derivative changes over time. This polarity change pattern may be a binary number with a predetermined number of digits assigned to L cardiac cycles. The polarity change pattern may also correspond to a time period from the beginning of the systole in the first cycle to the end of the diastole in the Lth cycle, where L is any positive integer. The polarity change pattern may also be a binary number in which a positive polarity of the Doppler waveform derivative is assigned a 1 (high) and a negative polarity of the Doppler waveform derivative is assigned a 0 (low).

[0063] The image processor 34 determines the degree of approximation between the polarity change pattern of the Doppler waveform line differential value and a pre-stored polarity change pattern for the artery. The degree of approximation may be, for example, a cross-correlation value. If the degree of approximation exceeds a predetermined threshold Th1, the image processor 34 determines that the observed region is an artery. If the degree of approximation is equal to or less than the threshold Th1, the image processor 34 determines that the observed region is a vein.

[0064] The image processing unit 34 may also determine the degree of approximation between the polarity change pattern of the Doppler waveform line differential value and a polarity change pattern stored in advance for a vein. In this case, the image processing unit 34 determines that the observed region is a vein when the degree of approximation exceeds a predetermined threshold Th2, and determines that the observed region is a vein when the degree of approximation is equal to or less than the threshold Th2.

[0065] The blood vessel determination may be performed based on the evaluation area S(t) between the Doppler waveform line E(t) and a reference line indicating the reference value V. The Doppler waveform line E(t) is shown in the upper part of Fig. 6, and the evaluation area S(t) is shown in the lower part.

[0066] The image processing unit 34 acquires the evaluation area S(t) at a predetermined time interval and obtains a time waveform of the evaluation area S(t) corresponding to L cardiac cycles. The image processing unit 34 stores time waveform patterns of the evaluation area S(t) for each of the artery and the vein. The time waveform patterns may be obtained by normalizing a predetermined L cardiac cycle on the time axis by a predetermined time length.

[0067] The image processing unit 34 normalizes the time waveform of the evaluation area S(t) on the time axis by a predetermined L cardiac cycles, and calculates the degree of approximation between the normalized time waveform and a pre-stored time waveform pattern for an artery. The degree of approximation may be, for example, a cross-correlation value. If the degree of approximation exceeds a predetermined threshold value Th3, the image processing unit 34 determines that the observed region is an artery, and if the degree of approximation is equal to or less than the threshold value Th3, the image processing unit 34 determines that the observed region is a vein.

[0068] The image processing unit 34 may also calculate the degree of approximation between the time waveform of the evaluation area S(t) normalized on the time axis and the stored time waveform pattern for the vein. In this case, if the degree of approximation exceeds a predetermined threshold Th4, the observed region is determined to be a vein, and if the degree of approximation is equal to or less than the threshold Th4, the observed region is determined to be a vein.

[0069] The image processor 34 may perform blood vessel determination based on the degree of approximation between the Doppler waveform line E(t), which is the time differential value dS(t) / dt of the evaluation area S(t), and a time waveform pattern stored in advance for an artery or a vein. 2 S(t) / dt 2 The blood vessel determination may be performed based on the degree of similarity between the waveform pattern and a pre-stored time waveform pattern for an artery or vein.

[0070] When operating in color Doppler mode, the image processing unit 34 may perform blood vessel determination based on the degree of dispersion of the Doppler frequency of post-phased received signals acquired multiple times N times in one direction of the transmit and receive beams (hereinafter referred to as "Doppler frequency dispersion"). When the blood flow velocity v(r) is calculated according to the above (Equations 1) to (Equation 3), the degree of Doppler frequency dispersion may be calculated based on J-1 adjacent temporal Doppler frequencies calculated according to (Equation 4).

[0071] That is, the color Doppler processor 40 calculates z(r, q)·z(r, q+1) which is added up on the right side of (Equation 2). * Using the real and imaginary parts of the above equations, the adjacent time Doppler frequency fa(r,q) is calculated for each of q=1 to J-1 according to (Equation 4).

[0072]

number

[0073] The color Doppler processing unit 40 calculates the Doppler frequency variability for the J-1 adjacent time Doppler frequencies fa(r,1), fa(r,2), ... fa(r,J-1), and outputs it to the image processing unit 34. The Doppler frequency variability may be a value indicating the variance, standard deviation, etc., for the J-1 adjacent time Doppler frequencies.

[0074] When the Doppler frequency variation degree exceeds a predetermined threshold Th5, the image processing unit 34 determines that the observation site is an artery, and when the Doppler frequency variation degree is equal to or less than the threshold Th5, the image processing unit 34 determines that the observation site is a vein.

[0075] If aliasing occurs when operating in CW Doppler mode or color Doppler mode, the image processor 34 may determine that the blood vessel is an artery. Here, aliasing in CW Doppler mode refers to the Doppler waveform being displayed periodically and repeatedly along the vertical axis. Aliasing in color Doppler mode refers to the phenomenon in which the polarity of the blood flow velocity v(r) expressed by Equation 3 changes discontinuously with time or region. For example, there is a phenomenon in which the blood flow velocity v(r) increases in the negative direction over time and then suddenly changes to a positive value. There is also a phenomenon in which the blood flow velocity v(r) increases in the negative direction along a certain direction of the acquired region and then suddenly changes to a positive value. Aliasing appears in B-mode color Doppler images as a phenomenon in which colors change suddenly over time. Furthermore, if blue is applied to areas where blood flows away from the ultrasonic probe 14 and red is applied to areas where blood flows toward the ultrasonic probe 14, a aliasing phenomenon occurs in which areas that should be red are colored blue, or areas that should be blue are colored red.

[0076] When aliasing occurs, the control unit 22 may adjust the repetition frequency PRF so that aliasing does not occur on the display image. When the scale factor k is increased, the control unit 22 may control the beam control unit 10, the transmitter 12, the receiver 20, and the information processing unit 26 so that the repetition frequency PRF is increased to a level that avoids aliasing. Furthermore, when the scale factor k is decreased, the control unit 22 may control the beam control unit 10, the transmitter 12, the receiver 20, and the information processing unit 26 so that the repetition frequency PRF is decreased. By lowering the repetition frequency PRF, the display resolution in the vertical axis direction is improved.

[0077] The image processing unit 34 may determine the scale factor ka for the arteries and the scale factor kv for the veins based on the area between the Doppler waveform line E(t) and a reference line indicating the reference value V0. The image processing unit 34 may calculate the time integral value of |Et(t)-V0|, for example, over a time range going back a predetermined number of N cardiac cycles from the current time point, or over a time range going back a predetermined time from the current time point. The image processing unit 34 may increase the scale factor ka for the arteries and the scale factor kv for the veins as the time integral value decreases.

[0078] For arteries, the image processor 34 may determine the scale factor ka so that the proportion R of the area between ka times the Doppler waveform line E(t) and the reference line that occupies the displayed image is equal to or greater than a certain threshold value Ta1 and equal to or less than a certain threshold value Ta2 (Ta1≦R≦Ta2).For veins, the image processor 34 may determine the scale factor kv so that the proportion R of the area between kv times the Doppler waveform line E(t) and the reference line that occupies the displayed image is equal to or greater than a certain threshold value Tv1 and equal to or less than a certain threshold value Tv2 (Tv1≦R≦Tv2).Here, the threshold value Ta1 is greater than the threshold value Tv2.

[0079] A case where a region other than the vicinity of the mitral valve is observed will be described. The left side of FIG. 7 shows an example of a B-mode color Doppler image acquired near the abdominal aorta. The right side of FIG. 7 shows a Doppler waveform acquired near the abdominal aorta. FIG. 8 also shows the Doppler waveform line E(t) along with the Doppler waveform. Unlike near the mitral valve of the heart, blood flow near the abdominal aorta is unidirectional. In the example shown in FIG. 8, 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 processing unit 34 multiplies the amplitude SW by the scale factor k=ka to obtain the display width Vs as Vs=k·SW.

[0080] For the abdominal aorta, thresholds and the like for determining blood vessels are set so that the image processing unit 34 determines that the observed site is an artery. 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.

[0081] The left side of Figure 9 shows an example of a B-mode color Doppler image acquired near the portal vein of the liver. The right side of Figure 9 shows a Doppler waveform acquired near the portal vein. Figure 10 also shows the Doppler waveform line E(t) along with the Doppler waveform. Unlike near the mitral valve of the heart, blood flow near the portal vein is unidirectional. In the example shown in Figure 10, the reference value V0 is on the negative side of the baseline 52, and the amplitude SW is SW = max(|Vp - V0|, |Vn - V0|) = V0 - Vn. The image processing unit 34 multiplies the amplitude SW by the scale factor k to obtain the display width Vs as Vs = k·SW.

[0082] For the portal vein, thresholds and the like for determining blood vessels may be set so that the image processing unit 34 determines that the observed site is an artery, or thresholds and the like for determining blood vessels may be set so that the image processing unit 34 determines that the observed site is a vein. 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.

[0083] In the above, an embodiment has been described 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, by calculating a weighted average value of blood flow velocity for each time period using frequency spectrum component values ​​as weighting values, and then averaging the weighted average values ​​of blood flow velocity over a time range going back a predetermined number of N cardiac cycles from the current time. Alternatively, the center of gravity of the Doppler waveform may be defined as the average value of the weighted average values ​​of blood flow velocity over a time range going back a predetermined time from the current time.

[0084] The image processing unit 34 may perform vascular determination and update the scale factor k at timings according to the pulsation of the subject 18. For example, the image processing unit 34 may perform vascular determination and update the scale factor k every M cardiac cycles, where M is a positive integer. FIG. 11 conceptually shows a Doppler waveform 60 and an update timing 58 of the scale factor k when vascular determination is performed every M cardiac cycles and the scale factor k is updated. The image processing unit 34 may also perform vascular determination and update the scale factor k every update cycle T, where T is the update cycle. FIG. 12 conceptually shows a Doppler waveform 60 and an update timing 58 of the scale factor k when vascular determination is performed every update cycle T and the scale factor k is updated.

[0085] Furthermore, when an operation for updating the scale factor k is performed on the operation unit 24, the image processing unit 34 may execute the blood vessel determination and update the scale factor k.

[0086] The image processing unit 34 may automatically perform blood vessel determination and set the scale factor k according to the diagnostic situation. The diagnostic situation is specified by, for example, the observation site such as the heart, liver, or abdomen, and the lesions that may be found in each observation site. The diagnostic situation may be recognized by the image processing unit 34 via a user interface.

[0087] Furthermore, the image processing unit 34 may sequentially determine the amplitude SW=max(|Vp-V0|, |Vn-V0|) in a time range going back a predetermined number of N cardiac cycles from the current time, or in a time range going back a predetermined time from the current time. The image processing unit 34 may automatically perform blood vessel determination and set the scale factor k when a later determined amplitude SW changes beyond a predetermined threshold value ThSW with respect to an earlier determined amplitude SW.

[0088] [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 using the ultrasonic probe; an information processing unit that processes the received signal output from the receiving unit, The information processing unit generating Doppler waveform data based on the received signals; determining whether the observation site is an artery or a vein based on the Doppler waveform data; An ultrasonic diagnostic apparatus characterized in that a display range of blood flow velocity indicated by a Doppler waveform is determined according to a result of the determination. Configuration 2: 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 using the ultrasonic probe; an information processing unit that processes the received signal output from the receiving unit, The information processing unit generating Doppler waveform data based on the received signals; An ultrasound diagnostic device that determines whether an observation site is an artery or a vein based on the degree of variation in Doppler frequency of multiple received signals obtained by transmitting and receiving ultrasound multiple times, and determines a display range of blood flow velocity indicated by the Doppler waveform according to the determination result. Configuration 3: 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 using the ultrasonic probe; an information processing unit that processes the received signal output from the receiving unit, The information processing unit generating Doppler waveform data and color Doppler data based on the received signals; An ultrasonic diagnostic apparatus characterized in that it determines whether the observed region is an artery or a vein based on the color Doppler data, and determines the display range of the blood flow velocity indicated by the Doppler waveform according to the determination result. Configuration 4: The ultrasound diagnostic apparatus according to configuration 3, The information processing unit 10. An ultrasonic diagnostic apparatus comprising: a first section for detecting an artery; a second section for detecting a vein; and a third section for detecting an artery and a vein, the second section being detected based on whether aliasing occurs in the color Doppler data. Configuration 5: The ultrasound diagnostic apparatus according to any one of configurations 1 to 4, The information processing unit An ultrasonic diagnostic apparatus characterized in that a scale factor for displaying the Doppler waveform is determined in accordance with the determination result. Configuration 6: 6. The ultrasound diagnostic apparatus according to claim 5, The information processing unit determining a reference value of a Doppler waveform line obtained from the Doppler waveform data; and determining the scale factor in accordance with the area of ​​a region between a Doppler waveform line determined from the Doppler waveform data and a reference line indicated by the reference value, in addition to the determination result. Configuration 7: 6. The ultrasound diagnostic apparatus according to claim 5, The information processing unit determining a maximum value, a minimum value, and a reference value of a Doppler waveform line obtained from the Doppler waveform data; The ultrasonic diagnostic apparatus is characterized in that the scale factor is determined based on the maximum value, the minimum value, and the reference value in addition to the determination result. Configuration 8: The ultrasound diagnostic apparatus according to configuration 1, The information processing unit An ultrasonic diagnostic apparatus characterized in that it is determined whether the observed region is an artery or a vein based on a time differential value of a Doppler waveform line obtained from the Doppler waveform data. Configuration 9: The ultrasound diagnostic apparatus according to configuration 1, The information processing unit An ultrasonic diagnostic apparatus characterized in that it determines whether the observed region is an artery or a vein based on a time integral value of a Doppler waveform line obtained from the Doppler waveform data. Configuration 10 The ultrasound diagnostic apparatus according to configuration 1, The information processing unit 10. An ultrasonic diagnostic apparatus comprising: a first section for detecting an ultrasound wave; a second section for detecting an ultrasound wave; a third section for detecting an ultrasound wave; Configuration 11: The ultrasound diagnostic apparatus according to any one of configurations 1 to 10, a pulse detection device for detecting the pulse of the subject; The information processing unit An ultrasonic diagnostic apparatus characterized in that it determines whether the observation site is an artery or a vein at a timing according to the pulsation of the subject. Configuration 12: 12. The ultrasound diagnostic apparatus according to any one of configurations 1 to 11, An ultrasonic diagnostic apparatus, characterized in that a repetition frequency when the transmitting unit transmits the ultrasonic waves is set in accordance with the display range. [Explanation of symbols]

[0089] 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 whether the observation site is an artery or a vein based on the Doppler waveform data; An ultrasonic diagnostic apparatus characterized in that a display range of blood flow velocity indicated by a Doppler waveform is determined in accordance with a result of the determination.

2. 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; 1. An ultrasound diagnostic device that determines whether an observation site is an artery or a vein based on the degree of variation in Doppler frequency of multiple received signals obtained by transmitting and receiving ultrasound multiple times, and determines a display range of blood flow velocity indicated by a Doppler waveform in accordance with the determination result.

3. 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 and color Doppler data based on the received signals; An ultrasonic diagnostic apparatus characterized in that it determines whether the observed part is an artery or a vein based on the color Doppler data, and determines a display range of the blood flow velocity indicated by the Doppler waveform in accordance with the determination result.

4. 4. The ultrasonic diagnostic apparatus according to claim 3, The information processing unit includes:

2. An ultrasonic diagnostic apparatus comprising: a first section for detecting an abnormality in a blood vessel; a second section for detecting an abnormality in the blood vessel;

5. The ultrasonic diagnostic apparatus according to any one of claims 1 to 4, The information processing unit includes: and determining a scale factor for displaying the Doppler waveform in accordance with the result of the determination.

6. 6. The ultrasonic diagnostic apparatus according to claim 5, The information processing unit includes: A reference value of a Doppler waveform line is obtained from the Doppler waveform data; The ultrasonic diagnostic apparatus according to claim 1, wherein the scale factor is determined in accordance with an area of ​​a region between a Doppler waveform line calculated from the Doppler waveform data and a reference line indicated by the reference value in addition to the result of the determination.

7. 6. The ultrasonic diagnostic apparatus according to claim 5, The information processing unit includes: determining a maximum value, a minimum value and a reference value of a Doppler waveform line obtained from the Doppler waveform data; 4. An ultrasonic diagnostic apparatus comprising: an ultrasonic diagnostic device that determines the scale factor based on the determination result, as well as the maximum value, the minimum value, and the reference value.

8. 2. The ultrasonic diagnostic apparatus according to claim 1, The information processing unit includes: an ultrasonic diagnostic apparatus for determining whether the observed portion is an artery or a vein based on a time differential value of a Doppler waveform line calculated from the Doppler waveform data;

9. 2. The ultrasonic diagnostic apparatus according to claim 1, The information processing unit includes: an ultrasonic diagnostic apparatus for determining whether the observed portion is an artery or a vein based on a time integral value of a Doppler waveform line obtained from the Doppler waveform data;

10. 2. The ultrasonic diagnostic apparatus according to claim 1, The information processing unit includes:

2. An ultrasonic diagnostic apparatus comprising: a first section for detecting an abnormality in a blood vessel; a second section for detecting an abnormality in the blood vessel;

11. The ultrasonic diagnostic apparatus according to any one of claims 1 to 4, a pulse detection device for detecting the pulse of the subject, The information processing unit includes:

2. An ultrasonic diagnostic apparatus comprising: a first section for detecting an artery or a vein; and a second section for detecting a vein.

12. The ultrasonic diagnostic apparatus according to any one of claims 1 to 4, 2. An ultrasonic diagnostic apparatus comprising: a transmitting section that transmits ultrasonic waves at a repetition frequency set in accordance with the display range.

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