JP2013005957A - Method and device for displaying doppler images - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for displaying Doppler images, that ensures the display of blood flow components only, while removing all clutter components.SOLUTION: After ultrasound waves are sent toward a subject from a probe 11, an ultrasonic echo signal is obtained from the received ultrasound waves reflected by the subject, based on which a Doppler signal is generated. Then, the Doppler signal undergoes highpass filtering processing so that clutter components can be removed and blood flow components can be extracted. Based upon the highpass-filtered Doppler signal, a display means 14 displays an image showing blood flow components. In such a Doppler image display method as described above, pulsed light is delivered to the subject from a light source 13, and then acoustic waves emitted from the subject after receiving the pulsed light are detected by detection means 11 and 22 to obtain an optoacoustic signal. Based upon the frequency range of the blood flow components indicated by the optoacoustic signal, filter bandwidth control means 40 and 42 determines cutoff frequency for highpass filtering processing.

Description

  The present invention relates to a Doppler image display method that obtains a Doppler signal from an ultrasonic echo signal and displays a blood flow component based on the Doppler signal, and an apparatus that implements the method.

  Conventionally, as shown in Patent Documents 1 and 2, for example, an ultrasonic echo signal obtained by transmitting an ultrasonic wave toward a subject such as a human body and receiving a reflected ultrasonic wave reflected by the subject at that time A Doppler image display method for generating a Doppler signal (Doppler shift signal) from a signal and displaying a blood flow component based on the Doppler signal is known. In this type of Doppler image display method, generally, the Doppler signal is subjected to high-pass filtering processing to remove clutter components that are low frequency components, that is, components such as organs that move slowly, and blood flow components that are high frequency components are removed. I try to extract. The high-pass filtering process is normally performed using an MTI (Moving Target Indicator) filter.

  On the other hand, as shown in Patent Documents 3 and 4, for example, a photoacoustic imaging apparatus that images the inside of a living body using a photoacoustic effect is known. In this photoacoustic imaging apparatus, a living body is irradiated with pulsed light such as pulsed laser light. Inside the living body that has been irradiated with the pulsed light, the living tissue that has absorbed the energy of the pulsed light undergoes volume expansion due to heat and generates acoustic waves. Therefore, it is possible to detect the acoustic wave with an ultrasonic probe or the like and visualize the inside of the living body based on the electrical signal (photoacoustic signal) obtained thereby. Since this photoacoustic imaging technique is designed to construct an image based only on acoustic waves emitted from a specific absorber, it is suitable for imaging a specific tissue in a living body, such as a blood vessel. It has become.

JP 2005-31632 A JP-A-8-010259 JP 2005-21380 A Special table 2010-512929

  In the conventional Doppler image display method in which the blood flow component, which is a high-frequency component, is extracted by the high-pass filtering process described above, a part of the blood flow component is lost or the clutter component is removed during the high-pass filtering process. The problem of not being cut was recognized.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a Doppler image display method capable of reliably displaying only a blood flow component without leaving a clutter component.

  It is another object of the present invention to provide a Doppler image display apparatus that can implement the above-described Doppler image display method.

A first Doppler image display method according to the present invention includes:
Send ultrasound to the subject,
Generating a Doppler signal from an ultrasonic echo signal obtained by receiving reflected ultrasonic waves reflected by the subject,
This Doppler signal is subjected to high-pass filtering to remove clutter components while extracting blood flow components,
In the Doppler image display method for displaying an image showing the blood flow component based on the Doppler signal after the high-pass filtering process,
Irradiating the subject with pulsed light having a wavelength absorbed therein;
The photoacoustic signal is obtained by detecting the acoustic wave emitted from the subject in response to this pulsed light,
The cutoff frequency of the high-pass filtering process is determined based on the frequency band of the blood flow component indicated by the photoacoustic signal.

The second Doppler image display method according to the present invention includes:
Send ultrasound to the subject,
Generating a Doppler signal from an ultrasonic echo signal obtained by receiving reflected ultrasonic waves reflected by the subject,
This Doppler signal is subjected to high-pass filtering to remove clutter components while extracting blood flow components,
In the Doppler image display method for displaying an image showing the blood flow component based on the Doppler signal after the high-pass filtering process,
Irradiating the subject with pulsed light having a wavelength absorbed therein;
The photoacoustic signal is obtained by detecting the acoustic wave emitted from the subject in response to this pulsed light,
The filter characteristic of the high-pass filter used for the high-pass filtering process is determined based on the peak value and / or spectrum width of the blood flow component indicated by the photoacoustic signal.

  In the second Doppler image display method, it is desirable that the cutoff characteristic is steeper as the peak value is larger and / or the spectrum width is narrower.

  In the first and second Doppler image display methods according to the present invention described above, it is desirable to perform the high-pass filtering process using an MTI filter.

Furthermore, a third Doppler image display method according to the present invention includes:
Send ultrasound to the subject,
Generating a Doppler signal from an ultrasonic echo signal obtained by receiving reflected ultrasonic waves reflected by the subject,
In the Doppler image display method for displaying an image showing the blood flow component based on the Doppler signal,
Irradiating the subject with pulsed light having a wavelength absorbed therein;
The photoacoustic signal is obtained by detecting the acoustic wave emitted from the subject in response to this pulsed light,
The blood flow component in the image is corrected so as to approximate the blood flow component indicated by the photoacoustic signal.

  Note that the above correction is desirably performed by a spatial filtering process.

  Further, the first to third Doppler image display methods according to the present invention described above can be applied to any method of displaying a color Doppler image, a pulse Doppler image, a continuous wave Doppler image, and a power Doppler image.

On the other hand, the first Doppler image display device according to the present invention is:
Ultrasonic transmission means for transmitting ultrasonic waves toward the subject;
Ultrasonic receiving means for receiving reflected ultrasonic waves reflected by the subject and obtaining ultrasonic echo signals;
Means for generating a Doppler signal from the ultrasonic echo signal;
High-pass filtering means for extracting blood flow components while removing clutter components from the Doppler signal;
In a Doppler image display device comprising image display means for displaying an image showing the blood flow component based on the Doppler signal passed through the high-pass filtering means,
A light irradiation means for irradiating the subject with pulsed light having a wavelength absorbed therein;
Means for receiving the pulsed light and detecting an acoustic wave emitted from the subject to obtain a photoacoustic signal;
Filter band control means for determining a cutoff frequency of the high-pass filtering process based on the frequency band of the blood flow component indicated by the photoacoustic signal is provided.

The second Doppler image display device according to the present invention is
Ultrasonic transmission means for transmitting ultrasonic waves toward the subject;
Ultrasonic receiving means for receiving reflected ultrasonic waves reflected by the subject and obtaining ultrasonic echo signals;
Means for generating a Doppler signal from the ultrasonic echo signal;
High-pass filtering means for extracting blood flow components while removing clutter components from the Doppler signal;
In a Doppler image display device comprising image display means for displaying an image showing the blood flow component based on the Doppler signal passed through the high-pass filtering means,
A light irradiation means for irradiating the subject with pulsed light having a wavelength absorbed therein;
Means for receiving the pulsed light and detecting an acoustic wave emitted from the subject to obtain a photoacoustic signal;
Filter characteristic control means for determining a filter characteristic of a high-pass filter used for the high-pass filtering process based on a peak value and / or a spectrum width of a blood flow component indicated by the photoacoustic signal is provided. It is.

  It is preferable that the filter characteristic control means makes the cutoff characteristic of the filter characteristic steeper as the peak value is larger and / or the spectrum width is narrower.

  In the first and second Doppler image display devices according to the present invention described above, it is desirable that the high-pass filtering means is an MTI filter.

Furthermore, a third Doppler image display device according to the present invention is provided.
Ultrasonic transmission means for transmitting ultrasonic waves toward the subject;
Ultrasonic receiving means for receiving reflected ultrasonic waves reflected by the subject and obtaining ultrasonic echo signals;
Means for generating a Doppler signal from the ultrasonic echo signal;
In a Doppler image display device comprising image display means for displaying an image showing the blood flow component based on the Doppler signal,
A light irradiation means for irradiating the subject with pulsed light having a wavelength absorbed therein;
Means for receiving the pulsed light and detecting an acoustic wave emitted from the subject to obtain a photoacoustic signal;
Correction means for correcting the blood flow component in the image is provided so as to approximate the blood flow component indicated by the photoacoustic signal.

  The correction means is preferably a spatial filtering means.

  In addition, the first to third Doppler image display devices according to the present invention described above may be formed to display any of a color Doppler image, a pulse Doppler image, a continuous wave Doppler image, and a power Doppler image.

  As described above, since the photoacoustic imaging technology constructs an image based only on the acoustic wave emitted from a specific absorber, it can accurately image a blood vessel with blood flow. ing. That is, according to this photoacoustic imaging technique, it is possible to accurately image a portion where blood, which is a good light absorber, flows.

  Focusing on this point, in the first Doppler image display method according to the present invention, as described above, the subject is irradiated with pulsed light having a wavelength absorbed therein, and the pulsed light is received and emitted from the subject. Since the photoacoustic signal is obtained by detecting the generated acoustic wave and the cutoff frequency of the high-pass filtering process is determined based on the frequency band of the blood flow component indicated by the photoacoustic signal, the blood flow is accurately present. Using the photoacoustic signal indicating the portion, the cut-off frequency can be determined to an appropriate value that can reliably leave only the blood flow component without leaving the clutter component. Therefore, according to this Doppler image display method, it is possible to reliably display a Doppler image showing only a blood flow component without leaving a clutter component.

  In the second Doppler image display method according to the present invention, paying attention to the above points, the subject is irradiated with pulsed light having a wavelength absorbed therein, and the sound emitted from the subject by receiving this pulsed light. Since the photoacoustic signal is obtained by detecting the wave, and the filter characteristic of the high-pass filter used for the high-pass filtering process is determined based on the peak value and / or spectrum width of the blood flow component indicated by the photoacoustic signal. Using the photoacoustic signal that accurately indicates the part with blood flow, the filter characteristics of the high-pass filter can be determined to an appropriate value that can reliably leave only the blood flow component without leaving the clutter component. Become. Therefore, according to this Doppler image display method, it is possible to reliably display a Doppler image showing only a blood flow component without leaving a clutter component.

  In the third Doppler image display method according to the present invention, paying attention to the above points, the subject is irradiated with pulsed light having a wavelength absorbed therein, and the sound emitted from the subject by receiving this pulsed light. The photoacoustic signal is obtained by detecting the wave, and the blood flow component in the Doppler image is corrected so as to approximate the blood flow component indicated by the photoacoustic signal. By using the photoacoustic signal, a Doppler image showing only the blood flow component can be reliably displayed without leaving the clutter component.

  On the other hand, as described above, the first Doppler image display device according to the present invention emits light from the subject by receiving the pulsed light and the light irradiating means for irradiating the subject with the pulsed light having the wavelength absorbed therein. And a filter band control means for determining a cutoff frequency of the high-pass filtering processing based on a frequency band of a blood flow component indicated by the photoacoustic signal. Therefore, according to this apparatus, the first Doppler image display method according to the present invention can be implemented.

  Further, as described above, the second Doppler image display device according to the present invention is emitted from the subject by receiving the pulsed light and the light irradiating means for irradiating the subject with the pulsed light having the wavelength absorbed therein. A filter characteristic for determining a filter characteristic of a high-pass filter used for high-pass filtering processing based on a means for obtaining a photoacoustic signal by detecting an acoustic wave and a peak value and / or a spectrum width of a blood flow component indicated by the photoacoustic signal Therefore, according to this apparatus, the second Doppler image display method according to the present invention can be implemented.

  Further, as described above, the third Doppler image display device according to the present invention is emitted from the subject by receiving the pulsed light and the light irradiating means for irradiating the subject with the pulsed light having the wavelength absorbed therein. Since a means for detecting an acoustic wave to obtain a photoacoustic signal and a correcting means for correcting the blood flow component in the Doppler image so as to approximate the blood flow component indicated by the photoacoustic signal are provided, According to this apparatus, the third Doppler image display method according to the present invention can be implemented.

1 is a block diagram showing a schematic configuration of a Doppler image display device according to an embodiment of the present invention. Graph showing blood flow component indicated by photoacoustic signal The figure explaining the setting of the cutoff frequency of the high pass filter by this invention The figure explaining the setting of the high-pass filter characteristic by this invention The figure explaining correction | amendment of the Doppler image by this invention

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a basic configuration of an apparatus for performing a Doppler image display method according to an embodiment of the present invention. The Doppler image display device 10 is a color Doppler image display device as an example, and can acquire both a photoacoustic image and an ultrasonic image. An ultrasonic probe (probe) 11 and an ultrasonic unit 12 are provided. A laser light source unit 13 and an image display means 14 comprising, for example, a CRT or a liquid crystal display device.

  The laser light source unit 13 emits laser light having a center wavelength of 756 nm as an example. The subject is irradiated with the laser beam emitted from the laser light source unit 13. The laser light is preferably guided to the probe 11 using light guide means such as a plurality of optical fibers, and irradiated from the probe 11 portion toward the subject.

  The probe 11 performs output (transmission) of ultrasonic waves to the subject and detection (reception) of reflected ultrasonic waves reflected back from the subject. For this purpose, the probe 11 has, for example, a plurality of ultrasonic transducers arranged one-dimensionally. The probe 11 detects ultrasonic waves (acoustic waves) generated by the observation object in the subject absorbing the laser light from the laser light source unit 13 by using the plurality of ultrasonic transducers. The probe 11 detects the acoustic wave and outputs an acoustic wave detection signal, and detects the reflected ultrasonic wave and outputs an ultrasonic echo signal.

  When the above-described light guide means is coupled to the probe 11, the end portion of the light guide means, that is, the tip portions of the plurality of optical fibers, are arranged along the arrangement direction of the plurality of ultrasonic transducers. From there, laser light is irradiated toward the subject. Hereinafter, the case where the light guide means is coupled to the probe 11 as described above will be described as an example.

  When obtaining photoacoustic image information of a subject or acquiring an ultrasound image, the probe 11 is moved in a direction substantially perpendicular to the one-dimensional direction in which the plurality of ultrasound transducers are arranged. Are two-dimensionally scanned by laser light and ultrasonic waves. This scanning may be performed by an inspector moving the probe 11 manually, or a more precise two-dimensional scanning may be realized using a scanning mechanism.

  The ultrasonic unit 12 includes a reception circuit 22, a reception memory 23, a data separation unit 24, a photoacoustic information processing unit 25, a CF (color flow) mode processing unit 26, a B mode processing unit 27, a transmission control circuit 30, and the super A control unit 31 is provided for controlling the operation of each unit in the sonic unit 12.

  The receiving circuit 22 includes a preamplifier, an AD converter, and the like, and receives the acoustic wave detection signal and the ultrasonic echo signal output from the probe 11. The receiving circuit 22 amplifies the received acoustic wave detection signal and the ultrasonic echo signal by a preamplifier, and then samples them by the AD converter as a sampling means, and converts them into photoacoustic data and ultrasonic data as digital signals, respectively. Furthermore, processing such as phase matching and quadrature detection is performed on the converted data. The sampling is performed at a predetermined sampling period in synchronization with an AD clock signal input from the outside, for example.

  The laser light source unit 13 includes a Q-switch pulse laser 32 made of a Ti: Sapphire laser or the like and a flash lamp 33 as an excitation light source. The laser light source unit 13 is supplied with a light trigger signal for instructing light emission from the control means 31. When the light trigger signal is received, the flash lamp 33 is turned on and the Q switch pulse laser is turned on. 32 is excited. For example, when the flash lamp 33 sufficiently excites the Q switch pulse laser 32, the control means 31 outputs a Q switch trigger signal. When receiving the Q switch trigger signal, the Q switch pulse laser 32 turns on the Q switch and emits a pulse laser beam having a wavelength of 756 nm.

  Here, the time required from when the flash lamp 33 is turned on until the Q-switch pulse laser 33 is sufficiently excited can be estimated from the characteristics of the Q-switch pulse laser 33 and the like. In place of controlling the Q switch from the control means 31 as described above, the Q switch may be turned on after the Q switch pulse laser 32 is sufficiently excited in the laser light source unit 13. In that case, a signal indicating that the Q switch is turned on may be notified to the ultrasonic unit 12 side.

  The control unit 31 inputs an ultrasonic trigger signal for instructing ultrasonic transmission to the transmission control circuit 30. When receiving the ultrasonic trigger signal, the transmission control circuit 30 transmits an ultrasonic wave from the probe 11. The control means 31 outputs the optical trigger signal first, and then outputs an ultrasonic trigger signal. The light trigger signal is output to irradiate the subject with laser light and the acoustic wave is detected, and then the ultrasonic trigger signal is output to transmit the ultrasonic wave to the subject and the reflected ultrasonic wave. Is detected.

  The control means 31 further outputs a sampling trigger signal that instructs the start of sampling to the AD converter of the receiving circuit 22. The sampling trigger signal is output after the optical trigger signal is output and before the ultrasonic trigger signal is output, more preferably at the timing when the subject is actually irradiated with the laser light. Therefore, the sampling trigger signal is output in synchronization with the timing at which the control means 31 outputs the Q switch trigger signal, for example. When receiving the sampling trigger signal, the AD converter of the receiving circuit 22 starts sampling the acoustic wave detection signal output from the probe 11 and received by the receiving circuit 22.

  After outputting the optical trigger signal, the control means 31 outputs the ultrasonic trigger signal at the timing when the detection of the acoustic wave is finished. At this time, the AD converter of the receiving circuit 22 continues the sampling without interrupting the sampling of the acoustic wave detection signal. In other words, the control means 31 outputs an ultrasonic trigger signal in a state where the AD converter continues sampling the acoustic wave detection signal. When the probe 11 transmits ultrasonic waves in response to the ultrasonic trigger signal, the detection target of the probe 11 changes from acoustic waves to reflected ultrasonic waves. The AD converter continuously samples the acoustic wave detection signal and the ultrasonic echo signal by continuing the sampling of the detected ultrasonic echo signal.

  The reception circuit 22 stores photoacoustic data and ultrasonic data obtained by sampling in a common reception memory 23. The sampling data stored in the reception memory 23 is photoacoustic data up to a certain point, and becomes ultrasonic data from a certain point. The data separation unit 24 separates the photoacoustic data and the ultrasonic data stored in the reception memory 23, the photoacoustic data is input to the photoacoustic information processing unit 25, and the ultrasonic data is input to the CF mode processing unit 26 and B. Input to the mode processing unit 27.

  Hereinafter, generation and display of a Doppler image will be described. Ultrasonic data is input to the B-mode processing unit 27 in FIG. 1 as described above, and the B-mode processing unit 27 normally indicates the amplitude of reflected ultrasonic waves as the brightness (luminance) of points based on the ultrasonic data. An ultrasonic tomographic image is generated. An image signal indicating the ultrasonic tomographic image is input to the B / CF mixed display processing unit 46. In this case, in order to generate Doppler data to be described later, transmission / reception of ultrasonic waves is repeated a plurality of times for the same tomographic plane. The B-mode ultrasonic tomographic image is also generated based on the ultrasonic data obtained by the multiple times of ultrasonic transmission / reception.

  Then, each ultrasonic data obtained by the plurality of times of ultrasonic transmission / reception is input to the CF mode processing unit 26. The MTI processing unit 42 of the CF mode processing unit 26 has an MTI filter, an autocorrelation calculation unit, and the like. The MTI processing unit 42 first performs a high-pass filtering process that removes a relatively low-frequency signal component that is a clutter component from the ultrasonic data using an MTI filter and extracts a blood flow component that is a higher-frequency component. . Next, the MTI processing unit 42 obtains a Doppler shift signal by performing autocorrelation calculation or the like on the signal after the high-pass filtering process. This Doppler shift signal is input to the blood flow information calculation unit 43. The blood flow information calculation unit 43 calculates the blood flow velocity, blood flow echo intensity, blood flow velocity dispersion, and the like from the input signal, and performs color mapping of the blood flow echo intensity value of each point held as a floating point, for example. And output as RGB signals.

  The output of the blood flow information calculation unit 43 is subjected to noise removal processing in the noise removal processing unit 44 and then input to the post-processing unit 45. The post-processing unit 45 performs color flow processing for coloring the points given “1” in red, for example, and does not color the points given “0”, and an image obtained by the processing, that is, color Doppler. An image signal indicating an image is input to the B / CF mixed display processing unit 46. The B / CF mixed display processing unit 46 superimposes and combines the color Doppler image, that is, the image in which the blood flow component is shown as a color map, and the normal ultrasonic tomographic image by the B-mode processing. It is displayed on the display means 14.

  The above processing is sequentially performed on a plurality of cross sections of the subject along with the scanning by the movement of the probe 11 described above. By using color Doppler images and ultrasonic tomographic images relating to the plurality of cross sections, it is also possible to generate and display an image that three-dimensionally shows a blood flow portion as a color map.

  FIG. 3 shows an example of the cut-off frequency in the high-pass filtering process by the MTI processing unit 42. If the cutoff frequency of the MTI filter is set to f2 as shown in FIG. 2A, the blood flow component is also removed from the Doppler shift signal together with the low frequency signal component that is the clutter component. Become. Even if it is not so extreme, if the cutoff frequency of the MTI filter is improperly set, there may be a problem that a part of the blood flow component is removed from the Doppler shift signal.

  On the other hand, when the cutoff frequency of the MTI filter is extremely lower than f2, the blood flow component is not removed, but there is a problem that most of the clutter components are extracted without being removed.

  Hereafter, the point which prevents said problem is demonstrated. The spectrum processing unit 40 of the photoacoustic information processing unit 25 illustrated in FIG. 1 uses the spectrum of the blood flow portion indicated by the photoacoustic data related to the same cross section as the cross section from which the ultrasonic data for generating the Doppler shift signal is obtained. For example, the peak value of the spectrum, the spectrum width, and the frequency at which the peak value is taken are obtained. This spectrum is, for example, as shown in FIG. 2 and is based on photoacoustic data that can accurately image a blood flow portion as described above. Therefore, the spectrum accurately indicates blood flow components. It has become. The spectrum processing unit 40 obtains the lowest frequency f1 of this spectrum. The minimum frequency f1 is obtained by, for example, calculation of (frequency taking peak value) − (spectrum width / 2).

  The spectrum processing unit 40 inputs information indicating the minimum frequency f1 obtained as described above to the MTI processing unit. Based on this information, the MTI processing unit 42 sets the cutoff frequency in the high-pass filtering process to a frequency f3 as shown in FIG. As an example, the frequency f3 is set to a value higher than the lowest frequency f1 by a predetermined frequency Δf. By setting the cutoff frequency of the MTI filter to the value of f3 as described above, as clearly shown in FIG. 2 (2), the color Doppler image showing only the blood flow component is reliably displayed without leaving the clutter component. become able to.

  As is apparent from the above description, in this embodiment, the spectrum processing unit 40 and the MTI processing unit 42 constitute a filter band control means. An appropriate value of the predetermined frequency Δf can be obtained based on experiments and experience.

  Next, a Doppler image display method according to another embodiment of the present invention will be described. The method of this embodiment can also be implemented by the color Doppler image display device 10 shown in FIG. That is, in the present embodiment, the MTI processing unit 42 determines the characteristics of the MTI filter based on the peak value and the spectrum width of the blood flow component obtained by the spectrum processing unit 40. More specifically, the cutoff characteristic of the MTI filter is set to be steeper as the peak value of the blood flow component is larger and the spectrum width is narrower.

  FIG. 4 shows the above in an easy-to-understand manner. That is, (1) and (2) in the figure illustrate two blood flow components indicated by the photoacoustic data, but the former example has a larger peak value and a spectrum width than the latter example. Is narrower. Therefore, in this case, the cutoff characteristic of the MTI filter indicated by the one-dot chain line in FIG. 2 is a steeper Chebyshev type characteristic in the case of (1), and a relatively gentle Butterworth type characteristic in the case of (2). And More specifically, a plurality of types of filter characteristics in which some or all of the filter coefficients are different from each other are stored in the storage means in association with each pair of the peak value and the spectrum width, and the detected peak It is desirable to select a filter characteristic from the value and the spectrum width and to set the filter coefficient of the selected characteristic in the MTI filter.

  In this embodiment, the filter characteristics are determined based on both the peak value and the spectrum width of the blood flow component indicated by the photoacoustic data. However, the filter characteristics are determined based only on one of the peak value and the spectrum width. It may be determined.

  As is apparent from the above description, in the present embodiment, the spectrum processing unit 40 and the MTI processing unit 42 constitute filter characteristic control means.

  Next, a Doppler image display method according to still another embodiment of the present invention will be described. The method of this embodiment can also be implemented by the color Doppler image display device 10 shown in FIG. That is, in the present embodiment, the photoacoustic data output from the data separator 24 is input to the spatial filter creation unit 41 of the photoacoustic information processing unit 25. The spatial filter creation unit 41 sets a point where blood flow exists to “1” from the photoacoustic data related to the same cross section from which the ultrasonic data for which the Doppler shift signal is generated is obtained, and points where no blood flow exists. A spatial filter consisting of a mask indicated as “0” is created. FIG. 5 (1) conceptually shows this spatial filter. One square indicates a mask size composed of a plurality of pixels or one pixel, and a hatched portion indicates a blood flow portion. Yes.

  The spatial filter is sent to the post-processing unit 45 of the CF mode processing unit 26. Based on the spatial filter, the post-processing unit 45 corrects the blood flow portion of the color Doppler image so as to approximate the blood flow component indicated by the photoacoustic data. That is, the hatched portion in FIG. 5 (2) shows the blood flow component in the color Doppler image. If the mask in FIG. 5 (1) is superimposed on this, “1” is added to the portion other than the hatched portion. ”And there may be a“ 0 ”portion at a position indicating a blood flow component. Therefore, the post-processing unit 45 performs a spatial filtering process of interpolating the “1” portion other than the hatched portion as a blood flow portion while removing the blood flow component overlapping the “0” portion.

  Since the mask is based on photoacoustic data that can accurately image the blood flow portion as described above, if the spatial filtering process using the mask is performed, a color Doppler image based on the signal after the process is performed. Does not leave the clutter component and accurately shows only the blood flow component.

  As is apparent from the above description, in this embodiment, the spatial filter creation unit 41 and the post-processing unit 45 constitute correction means for correcting a blood flow component in a Doppler image.

  Note that the Doppler image display methods of the three embodiments described above may all be implemented together, or two of them may be implemented together, or one of them. Only may be implemented.

  Further, the Doppler image display device and method of the present invention are not limited to the above embodiment, and various modifications and changes made from the configuration of the above embodiment are also included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Color Doppler image display apparatus 11 Probe 12 Ultrasonic unit 13 Laser light source unit 14 Image display means 22 Reception circuit 23 Reception memory 24 Data separation means 25 Photoacoustic information processing part 26 CF mode processing part 27 B mode processing part 30 Transmission control circuit 31 Control Unit 32 Q Switch Laser 33 Flash Lamp 40 Spectrum Processing Unit 41 Spatial Filter Creation Unit 42 MTI Processing Unit 43 Blood Flow Information Calculation Unit 44 Noise Removal Processing Unit 45 Post-Processing Unit 46 B / CF Mixed Display Processing Unit

Claims (12)

Send ultrasound to the subject,
Generating a Doppler signal from an ultrasonic echo signal obtained by receiving reflected ultrasonic waves reflected by the subject,
This Doppler signal is subjected to high-pass filtering to remove clutter components while extracting blood flow components,
In the Doppler image display method for displaying an image showing the blood flow component based on the Doppler signal after the high-pass filtering process,
Irradiating the subject with pulsed light having a wavelength absorbed therein;
The photoacoustic signal is obtained by detecting the acoustic wave emitted from the subject in response to this pulsed light,
A Doppler image display method, comprising: determining a cutoff frequency of the high-pass filtering process based on a frequency band of a blood flow component indicated by the photoacoustic signal. Send ultrasound to the subject,
Generating a Doppler signal from an ultrasonic echo signal obtained by receiving reflected ultrasonic waves reflected by the subject,
This Doppler signal is subjected to high-pass filtering to remove clutter components while extracting blood flow components,
In the Doppler image display method for displaying an image showing the blood flow component based on the Doppler signal after the high-pass filtering process,
Irradiating the subject with pulsed light having a wavelength absorbed therein;
The photoacoustic signal is obtained by detecting the acoustic wave emitted from the subject in response to this pulsed light,
A Doppler image display method, comprising: determining a filter characteristic of a high-pass filter used for the high-pass filtering process based on a peak value and / or a spectrum width of a blood flow component indicated by the photoacoustic signal.   3. The Doppler image display method according to claim 2, wherein when the peak value is larger and / or when the spectrum width is narrower, the filter characteristic is steeper.   The Doppler image display method according to claim 1, wherein the high-pass filtering process is performed by an MTI filter. Send ultrasound to the subject,
Generating a Doppler signal from an ultrasonic echo signal obtained by receiving reflected ultrasonic waves reflected by the subject,
In the Doppler image display method for displaying an image showing the blood flow component based on the Doppler signal,
Irradiating the subject with pulsed light having a wavelength absorbed therein;
The photoacoustic signal is obtained by detecting the acoustic wave emitted from the subject in response to this pulsed light,
A Doppler image display method comprising correcting a blood flow component in the image so as to approximate the blood flow component indicated by the photoacoustic signal.   6. The Doppler image display method according to claim 5, wherein the correction is performed by a spatial filtering process. Ultrasonic transmission means for transmitting ultrasonic waves toward the subject;
Ultrasonic receiving means for receiving reflected ultrasonic waves reflected by the subject and obtaining ultrasonic echo signals;
Means for generating a Doppler signal from the ultrasonic echo signal;
High-pass filtering means for extracting blood flow components while removing clutter components from the Doppler signal;
In a Doppler image display device comprising image display means for displaying an image showing the blood flow component based on the Doppler signal passed through the high-pass filtering means,
A light irradiation means for irradiating the subject with pulsed light having a wavelength absorbed therein;
Means for receiving the pulsed light and detecting an acoustic wave emitted from the subject to obtain a photoacoustic signal;
A Doppler image display device comprising: a filter band control unit that determines a cutoff frequency of the high-pass filtering process based on a frequency band of a blood flow component indicated by the photoacoustic signal. Ultrasonic transmission means for transmitting ultrasonic waves toward the subject;
Ultrasonic receiving means for receiving reflected ultrasonic waves reflected by the subject and obtaining ultrasonic echo signals;
Means for generating a Doppler signal from the ultrasonic echo signal;
High-pass filtering means for extracting blood flow components while removing clutter components from the Doppler signal;
In a Doppler image display device comprising image display means for displaying an image showing the blood flow component based on the Doppler signal passed through the high-pass filtering means,
A light irradiation means for irradiating the subject with pulsed light having a wavelength absorbed therein;
Means for receiving the pulsed light and detecting an acoustic wave emitted from the subject to obtain a photoacoustic signal;
And a filter characteristic control means for determining a filter characteristic of a high-pass filter used for the high-pass filtering process based on a peak value and / or a spectrum width of a blood flow component indicated by the photoacoustic signal. Image display device.   The filter characteristic control means makes the cutoff characteristic of the filter characteristic steeper as the peak value is larger and / or the spectrum width is narrower. Doppler image display device.   The Doppler image display device according to any one of claims 7 to 9, wherein the high-pass filtering means comprises an MTI filter. Ultrasonic transmission means for transmitting ultrasonic waves toward the subject;
Ultrasonic receiving means for receiving reflected ultrasonic waves reflected by the subject and obtaining ultrasonic echo signals;
Means for generating a Doppler signal from the ultrasonic echo signal;
In a Doppler image display device comprising image display means for displaying an image showing the blood flow component based on the Doppler signal,
A light irradiation means for irradiating the subject with pulsed light having a wavelength absorbed therein;
Means for receiving the pulsed light and detecting an acoustic wave emitted from the subject to obtain a photoacoustic signal;
A Doppler image display device comprising correction means for correcting a blood flow component in the image so as to approximate the blood flow component indicated by the photoacoustic signal.   The Doppler image display device according to claim 11, wherein the correction unit is a spatial filtering unit.

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