The present disclosure relates to ultrasound flow imaging methods and systems, and more particularly to display technologies for flow imaging in an ultrasound imaging system.
In a medical ultrasound imaging device, flow imaging is usually based on a two-dimensional image. Taking blood flow as an example, ultrasound waves are transmitted to an object to be examined, and the Doppler effect between red blood cells and the ultrasound waves are used by a color Doppler imaging device to obtain images, similar to pulsed wave Doppler imaging and continuous wave Doppler imaging. The color Doppler imaging device may include a two-dimensional display system, a pulsed wave Doppler (one-dimensional Doppler) blood flow analysis system, a continuous wave Doppler blood flow measurement system, and/or a color Doppler (two-dimensional Doppler) blood flow display system. An oscillator may generate two orthogonal signals between which the phase difference is π/2. The two orthogonal signals may respectively multiply the Doppler blood flow signal, and the products may be converted into digital signals by an A/D converter. After filtering by a comb filter to remove the low frequency components generated by vascular wall, valves or the like, the digital signals may be sent to an autocorrelator where autocorrelation may be performed. Since each sample includes the Doppler blood flow information generated by many red blood cells, the signals obtained by the autocorrelation are mixed signals of multiple blood flow velocities. The results of the autocorrelation may be sent to a velocity calculator and a variance calculator to obtain average velocities, which may be stored in a digital scan converter (DSC) together with blood flow spectrum information processed by FFT processing and two-dimensional image information. Finally, a color processor may perform a pseudo-color coding on the blood flow information based on the direction of the blood flow and the magnitude of the velocities, which may then be rendered on a color display.
In color Doppler blood flow imaging, only the magnitudes and directions of the velocities of the blood flow in the scanning plane are displayed. However, not only laminar flow exists in the blood flow. Rather, more complex flows, such as vortices or the like, may generally exists at arterial stenosis. Two-dimensional ultrasound scanning can only obtain the magnitudes and directions of the velocities of the blood flow in the scanning plane. With two-dimensional ultrasound imaging, the flow characteristics of the liquid in blood vessels or other tubular or liquid-contained organs cannot be realistically represented. In two-dimensional ultrasound imaging, only several isolated section images are displayed, or a pseudo three-dimensional image is obtained using several section images, which does not provide comprehensive and accurate information to the doctor. Therefore, it is desired to improve the existing flow imaging technologies to provide a more intuitive display solution for flow.
Accordingly, in order to overcome the drawbacks in the prior art, an ultrasound flow imaging method and ultrasound imaging system may be provided, which can provide more intuitive display for blood flow information and provide a better observation perspective for the user.
In some embodiments, an ultrasound flow imaging method may include: transmitting volume ultrasound beams to a scanning target; receiving echoes of the volume ultrasound beams and obtaining volume ultrasound echo signals; obtaining three-dimensional ultrasound image data of at least a part of the scanning target based on the volume ultrasound echo signals; obtaining flow velocity vector information of a target point in the scanning target based on the volume ultrasound echo signals; and displaying the three-dimensional ultrasound image data to form a spatial stereoscopic image of the scanning target and superimposing the flow velocity vector information in the spatial stereoscopic image.
In some embodiments, an ultrasound flow imaging system may include: a probe; a transmitting circuit which excites the probe to transmit volume ultrasound beams to a scanning target; a receiving circuit and a beam forming unit which receive echoes of the volume ultrasound beams and obtain volume ultrasound echo signals; a data processing unit which obtains three-dimensional ultrasound image data of at least a part of the scanning target based on the volume ultrasound echo signals and obtains flow velocity vector information of a target point in the scanning target based on the volume ultrasound echo signals; and a stereoscopic display device which receives the three-dimensional ultrasound image data and the flow velocity vector information of the target point, displays the three-dimensional ultrasound image data to form a spatial stereoscopic image of the scanning target, and superimposes the flow velocity vector information in the spatial stereoscopic image.
The present disclosure provides an ultrasound flow imaging method and system which can display the movement of the fluid in a spatial stereoscopic image, thereby providing more observation perspectives for the observer.
In an ultrasound imaging process, the transmitting circuit 2 may transmit transmitting pulses, which have been delay focused and have certain amplitude and polarity, to the probe 1 through the transmitting/receiving switch 3. The probe 1 may be excited by the transmitting pulses and thereby transmit ultrasound waves to a scanning target (for example, organs, tissue, blood vessels or the like within a human or animal body, not shown), receive ultrasound echoes which are reflected by a target region and carry information related to the scanning target after a certain time interval, and convert the ultrasound echoes into electric signals. The receiving circuit may receive the electric signals converted by the probe 1 to obtain volume ultrasound echo signals and send the volume ultrasound echo signals to the beam-forming unit 5. The beam-forming unit 5 may perform processing such as a focus delaying, a weighting and a channel summing, etc. on the volume ultrasound echo signals and then send the volume ultrasound echo signals to the signal processing unit 6, where related signal processing procedures will be performed.
The volume ultrasound echo signals processed by the signal processing unit 6 may be sent to the image processing unit 7, where the signals may be processed in different ways according to the imaging mode desired by the user in order to obtain image data in different mode, such as two-dimensional image data and three-dimensional image data. Then, the image data may undergo the processing such as a logarithmic compression, a dynamic range adjustment and a digital scan conversion, etc. to form ultrasound image data of different modes, for example, including two-dimensional image data such as B images, C images or D images, etc., and three-dimensional ultrasound image data which can be sent to the display device for three-dimensional or spatial stereoscopic display.
The three-dimensional ultrasound image data generated by the image processing unit 7 may be sent to the stereoscopic display device 8 for display to form a spatial stereoscopic image of the scanning target. The spatial stereoscopic image herein may refer to a real three-dimensional image displayed in a physical space based on holographic display technologies or volume three-dimensional display technologies, including single frame image or multiple-frame images.
The probe 1 may generally include an array of multiple transducers. Each time the ultrasound waves are transmitted, all or a part of the transducers of the probe 1 may be used. In this case, each or each part of the used transducers may be respectively excited by the transmitting pulse and respectively transmit ultrasound wave. The ultrasound waves transmitted by the transducers may superpose with each other during the propagation thereof such that a resultant ultrasound beam transmitted to the scanning target can be formed. The direction of the resultant ultrasound beam may be the “ultrasound propagation direction” mentioned in the present disclosure.
The used transducers may be simultaneously excited by the transmitting pulses. Alternatively, a certain time delay may exist between the excitation times of the used transducers by the transmitting pulses. By controlling the time delay between the excitation times of the used transducers by the transmitting pulses, the propagation direction of the resultant ultrasound beam can be changed, as described in detail below.
By controlling the time delay between the excitation times of the used transducers by the transmitting pulses, it may also be possible that the ultrasound waves transmitted by the used transducers neither focus nor completely diffuse during the propagation thereof, but form a plane wave which is substantially planar as a whole. In the present disclosure, such plane wave without a focus may be referred to as a “plane ultrasound beam.”
Alternatively, by controlling the time delay between the excitation times of the used transducers by the transmitting pulses, it may also be possible that the ultrasound waves transmitted by the transducers are superposed at a predetermined position such that the strength of the ultrasound waves at the predetermined position is maximum, in other words, such that the ultrasound waves transmitted by the transducers may be “focused” at the predetermined position. Such predetermined position may be referred to as a “focus.” In this case, the obtained resultant ultrasound beam may be a beam focused at the focus, which may be referred to as a “focused ultrasound beam” in the present disclosure. For example,
Alternatively, by controlling the time delay between the excitation times of the used transducers by the transmitting pulses, it may also be possible that the ultrasound waves transmitted by the used transducers are diffused during the propagation to form a diffused wave which is substantially diffused as a whole. In the present disclosure, such diffused ultrasound wave may be referred to as a “diffused ultrasound beam.” An example of the diffused ultrasound beam is shown in
In the case that multiple transducers linearly arranged are excited simultaneously by electronic pulses, the transducers will simultaneously transmit ultrasound waves and the propagation direction of the resultant ultrasound beam will be the same as the normal direction of the plane on which the transducers are arranged. For example, for the plane beam vertically transmitted shown in
Similarly, regardless of the plane ultrasound beam, the focused ultrasound beam or the diffused ultrasound beam, the “steered angle” of the resultant beam formed between the direction of the resultant beam and the normal direction of the plane on which the transducers are arranged can be adjusted by adjusting the time delay between the excitation times of the used transducers by the transmitting pulses. The “resultant beam” herein may be the plane ultrasound beam, the focused ultrasound beam or the diffused ultrasound beam mentioned above.
When performing three-dimensional ultrasound imaging, a two-dimensional array probe may be used, as shown in
In the present disclosure, ultrasound beams which “are transmitted to a scanning target, propagate in a space in which the scanning target is located, and are used to form the scanning body above” may be regarded as a volume ultrasound beam, which may include the group of ultrasound beams transmitted one or more times. Therefore, based on the type of the ultrasound beam, the plane ultrasound beams which “are transmitted to a scanning target, propagate in a space in which the scanning target is located, and are used to form the scanning body above” may be regarded as a volume plane ultrasound beam, the focused ultrasound beams which “are transmitted to a scanning target, propagate in a space in which the scanning target is located, and are used to form the scanning body above” may be regarded as a volume focused ultrasound beam, and the diffused ultrasound beams which “are transmitted to a scanning target, propagate in a space in which the scanning target is located, and are used to form the scanning body above” may be regarded as a volume diffused ultrasound beam, etc. The volume ultrasound beam may include the volume plane ultrasound beam, the volume focused ultrasound beam, the volume diffused ultrasound beam, and so on. The name of the type of the ultrasound beam may be added between the “volume” and the “ultrasound beam.”
The volume plane ultrasound beam may generally almost cover the entire imaging area of the probe 1. In the case of performing ultrasound imaging using the volume plane ultrasound beam, one frame of three-dimensional ultrasound image (the one frame of ultrasound image herein should be understood as including one frame of two-dimensional image data or one frame of three-dimensional image data, and the same below) may be obtained by one transmitting, therefore the imaging frame rate may be very high. While in the case of performing ultrasound imaging using the volume focused ultrasound beam, since the beam is focused at the focus, only one or several scan lines can be obtained by each transmission, therefore multiple transmissions need to be performed to obtain all scan lines within the imaging area so as to obtain one frame of three-dimensional ultrasound image of the imaging area by combining all scan lines. Therefore, in the case of performing ultrasound imaging using the volume focused ultrasound beam, the frame rate is relatively low. However, the energy of the volume focused ultrasound beam is concentrated and the image data is only obtained at the energy concentrated location. Accordingly, the signal to noise ratio of the obtained echo signals is high and the ultrasound images with better quality can be obtained.
Based on ultrasound three-dimensional imaging, the system of the present disclosure may display the real ultrasound stereoscopic images and the velocity vectors of the flow in a superimposed manner. Therefore, the user can not only have a better viewing angle, but also a view the flow information, such as the velocities of the blood and the flow directions, etc. at the location being scanned in real time. Furthermore, the images can represent the path of travel of the flowing fluid more realistically. The fluid herein may include blood, intestinal fluid, lymph, tissue fluid, cell fluid or other body fluids. Various embodiments of the present disclosure will be described in details with reference to the drawings.
As shown in
As shown in
In the present disclosure, the volume ultrasound beams transmitted to the scanning target may include at least one of volume focused ultrasound beam, volume non-focused ultrasound beam, volume virtual source ultrasound beam, volume non-diffractive ultrasound beam, volume diffused ultrasound beam, volume plane ultrasound beam and other type of beam, or include the combination thereof including at least more than two types of beams (“more than” herein may include the number following this phrase itself, and the same below). Of course, the embodiments of the present disclosure will not be limited to the volume ultrasound beams mentioned above.
In some embodiments, as shown in
The scanning target may be the tubular tissue in which fluid flows in a human or animal body, such as organs, tissues, vessels or the like. The target points in the scanning target may be the points or locations of interest in the scanning target, which may generally be represented as, in the spatial stereoscopic image of the scanning target displayed by the stereoscopic display device, spatial points or spatial locations of interest which can be marked or displayed. A spatial point or spatial locations may be one spatial point or a spatial neighborhood of one spatial point, and the same below.
Alternatively, in step S100, the volume focused ultrasound beams may be transmitted to the scanning target such that the volume focused ultrasound beams propagate in the space in which the scanning target is located to form the scanning body. Thereby, in step S200, the echoes of the volume focused ultrasound beams may be received to obtain the volume focused ultrasound echo signals which may be used to reconstruct the three-dimensional ultrasound image data and/or calculate the velocity vectors of the flow at the target points in the scanning target.
Alternatively, as shown in
In the case that two types of volume ultrasound beams are used in step S100, the two types of volume ultrasound beams may be transmitted to the scanning target alternately. For example, the processes for transmitting the volume focused ultrasound beams to the scanning target may be inserted between the processes for transmitting the volume plane ultrasound beams to the scanning body. I.e. the step S101 and the step S102 shown in
In step S100, the volume ultrasound beams may be transmitted to the scanning target based on Doppler imaging technologies in order to obtain the volume ultrasound echo signals for calculating the flow velocity vectors at the target points. For example, the volume ultrasound beams may be transmitted to the scanning target in one ultrasound propagation direction such that the volume ultrasound beams propagate in the space in which the scanning target is located to form a scanning body. Then, the three-dimensional ultrasound image data used for calculating the flow velocity vectors at the target points may be obtained based on the volume ultrasound echo signals returned from the one scanning body.
Of course, in order to enable the calculated results of the flow velocity vectors at the target points to represent the velocity vectors at the target points in the real three-dimensional space more realistically, In some embodiments, the volume ultrasound beams may be transmitted to the scanning target in multiple ultrasound propagation directions, where each scanning body may be derived from the volume ultrasound beams transmitted in one ultrasound propagation direction. The volume ultrasound echo signals returned from the Multiple scanning bodies may be used to obtain the image data used for calculating the flow velocity vectors at the target points. For example, the step S200 and the step S400 may include:
first, receiving echoes from the ultrasound beams of the multiple scanning bodies to obtain multiple groups of echo signals;
then, one velocity component at the target point in the scanning target may be calculated based one of the multiple groups of echo signals, thereby respectively obtaining multiple velocity components based on the multiple groups of echo signals; and
synthesizing the velocity vector at the target point based on the multiple velocity components to obtain flow velocity vector information at the target point.
The multiple ultrasound propagation directions may include two or more ultrasound propagation directions.
During the transmitting of the ultrasound beams to the scanning target in multiple ultrasound propagation directions, the transmitting of the ultrasound beams to the scanning target in different ultrasound propagation directions may be performed alternately. For example, in the case that the volume ultrasound beams are transmitted to the scanning target in two ultrasound propagation directions, the volume ultrasound beams may be transmitted to the scanning target first in a first ultrasound propagation direction first, and then in a second ultrasound propagation, thereby achieving one scan cycle. Then, the scan cycle may be repeated sequentially. Or, the volume ultrasound beams may be transmitted to the scanning target first in one ultrasound propagation direction, and then in another ultrasound propagation direction, and so on, until the transmitting in all ultrasound propagation directions are performed. The different ultrasound propagation directions may be achieved by changing the time delay of each or each part of the transducers to be used in the transmitting of the ultrasound waves, which may be specifically understood with reference to the description with regard to
For example, the process of transmitting the volume plane ultrasound beams to the scanning target in multiple ultrasound propagation directions may include: transmitting, to the scanning target, a first volume ultrasound beam which has a first ultrasound propagation direction; and transmitting, to the scanning target, a second volume ultrasound beam which has a second ultrasound propagation direction. The echoes of the first volume ultrasound beam and the echoes of the second volume ultrasound beam may be received respectively to obtain first volume ultrasound echo signals and second ultrasound echo signals. Two velocity components may be obtained based on the two groups of ultrasound echo signals. The flow velocity vector at the target point may be obtained by synthesizing the two velocity components. The arrangement with regard to the ultrasound propagation direction may refer to the detailed description above with respect to
As another example, the process of transmitting the volume plane ultrasound beams to the scanning target in multiple ultrasound propagation directions may also include: transmitting the volume plane ultrasound beams to the scanning target in N (N is a natural number greater than or equal to 3) ultrasound propagation directions and receiving the echoes thereof to obtain N (N is a natural number greater than or equal to 3) groups of volume ultrasound echo signals each of which may be derived from the volume ultrasound beams transmitted in one ultrasound propagation direction. The N groups of volume ultrasound echo signals may be used to calculate the flow velocity vectors at the target points.
In addition, In some embodiments, a portion or all of the transducers may be excited to transmit the volume ultrasound beam to the scanning target in one or more ultrasound propagation directions. The volume ultrasound beams in the present embodiment may be, for example, volume plane ultrasound beam.
As another example, in some of the embodiments of the present disclosure, as shown in
In some embodiments, the volume ultrasound beams may be transmitted to the scanning target in each ultrasound propagation direction for multiple times to obtain multiple volume ultrasound echo signals for subsequent ultrasound image data processing. For example, the volume plane ultrasound beams may be transmitted to the scanning target respectively in multiple ultrasound propagation directions for multiple times, or the volume focused ultrasound beams may be transmitted to the scanning target respectively in one or more ultrasound propagation directions for multiple times. Each transmission of the volume ultrasound beams may correspondingly obtain one volume ultrasound echo signals.
The multiple transmitting of the volume ultrasound beams to the scanning target in different ultrasound propagation directions may be performed alternately, which enables the echo data obtained to be used to calculate the velocity vectors at the target points at substantially the same time in order to increase the calculation accuracy of the flow velocity vectors. For example, in the case that the volume ultrasound beams are respectively transmitted to the scanning target in three ultrasound propagation directions for N times, the volume ultrasound beams may first be transmitted to the scanning target in a first ultrasound propagation direction for at least one time, and then be transmitted to the scanning target in a second ultrasound propagation direction for at least one time, and then be transmitted to the scanning target in a third ultrasound propagation direction for at least one time, thereby achieving one scanning cycle. Finally, the scanning cycle above may be repeated sequentially until the transmitting in all of the ultrasound propagation directions is completed. In each scanning cycle, the number of the transmitting of the volume ultrasound beams in different ultrasound propagation directions may be the same, or may also be different with each other For example, in the case that the volume ultrasound beams are transmitted in two ultrasound propagation directions, the order of the transmitting may be A1 B1 A2 B2 A3 B3 A4 B4 . . . Ai Bi, and so on, where Ai represents the i-th transmitting in the first ultrasound propagation direction and Bi represents the i-th transmitting in the second ultrasound propagation direction. In the case that the volume ultrasound beams are transmitted in three ultrasound propagation directions, the order of the transmitting may be A1 B1 B1C1 A2 B2 B2C2 A3 B3 B3C3 . . . Ai Bi Bi Ci, and so on, where Ai represents the i-th transmitting in the first ultrasound propagation direction, Bi represents the i-th transmitting in the second ultrasound propagation direction, and Ci represents the i-th transmitting in the third ultrasound propagation direction.
In addition, in the case that two kinds of ultrasound beams are transmitted to the scanning target in step S100 above, the two kinds of ultrasound beams may be transmitted alternately. For example, in some embodiments, the step S100 may include:
first, transmitting volume focused ultrasound beams to the scanning target for multiple times to obtain reconstructed three-dimensional ultrasound image data;
and then, transmitting volume plane ultrasound beams to the scanning target in one or more ultrasound propagation direction to obtain image data used for calculating the velocity vectors at the target points.
Accordingly, the processes of transmitting volume focused ultrasound beams to the scanning target may be inserted between the processes of transmitting volume plane ultrasound beams to the scanning target. For example, the multiple transmitting of the volume focused ultrasound beams to the scanning target may be evenly inserted between the multiple transmitting of the volume plane ultrasound beams.
For example, the successive transmitting of the volume plane ultrasound beams “Ai Bi Ci” above may be mainly used to obtain data used for calculating the velocity information at the target point, while transmitting of the other kind of volume ultrasound beams used for obtaining the reconstructed three-dimensional ultrasound image may be inserted between the successive transmitting “Ai Bi Ci.” The way for alternately transmitting two kinds of beams will be described in detail below taking inserting the transmitting of the volume focused ultrasound beams between the successive transmitting of the volume plane ultrasound beams “Ai Bi Ci” as an example.
The volume plane ultrasound beams may be transmitted to the scanning target respectively in three ultrasound propagation directions for multiple times according to the following order:
A1 B1 Cl D1A2 B2 C2 D2 A3 B3 C3 D3 . . . Ai Bi CiDi, and so on.
Where Ai represents the i-th transmitting in the first ultrasound propagation direction, Bi represents the i-th transmitting in the second ultrasound propagation direction, Ci represents the i-th transmitting in the third ultrasound propagation direction, and Di represents the i-th transmitting of the volume focused ultrasound beams.
The methods above provide relatively simple ways for inserting the transmitting of the volume focused ultrasound beams. In addition, the transmitting of the volume focused ultrasound beam may be inserted for one time after the multiple transmitting of the volume plane ultrasound beams in different ultrasound propagation directions are completed, or, at least one portion of the multiple transmitting of the volume plane ultrasound beams to the scanning target and at least one portion of the multiple transmitting of the volume focused ultrasound beams to the scanning target may be performed alternately, etc. Besides, any method which can achieve alternately performing at least one portion of the multiple transmitting of the volume plane ultrasound beams to the scanning target and at least one portion of the multiple transmitting of the volume focused ultrasound beams to the scanning target may also be used. In the present embodiment, the volume focused ultrasound beams may be used to obtain better three-dimensional ultrasound image data, while the volume plane ultrasound beams may be used to obtain high real-time flow velocity vector information due to the high frame rate thereof. Furthermore, for better synchronization of the obtaining of the two kinds of data, the two kinds of ultrasound beams may be transmitted alternately.
Therefore, the order and the rules for performing the multiple transmitting of the volume ultrasound beams to the scanning target in different ultrasound propagation directions may be selected as needed, which will not be listed herein and not limited to the specific example provided above.
In step S200, the receiving circuit 4 and the beam-forming unit 5 may receive the echoes of the volume ultrasound beams transmitted in step S100 and obtain the volume ultrasound echo signals.
The type of the echoes of the volume ultrasound beams received and the volume ultrasound echo signals thereby generated may correspond to the type of the volume ultrasound beams transmitted in step S100. For example, in the case that the echoes of the volume focused ultrasound beams transmitted in step S100 are received, the volume focused ultrasound echo signals may be obtained; and in the case that the echoes of the volume plane ultrasound beams transmitted in step S100 are received, the volume plane ultrasound echo signals may be obtained; and so on. The name of the type of the ultrasound beams may be added between the “volume” and the “ultrasound echo signals.”
When the receiving circuit 4 and the beam-forming unit 5 receive the echoes of the volume ultrasound beams transmitted in step S100, the echoes of the volume ultrasound beams transmitted in step S100 may be received by each or each part of the transducers used in the transmitting of the ultrasound beams during the time-sharing transmitting and receiving; or, the transducers in the probe may be classified as receiving transducers and transmitting transducers, and each or each part of the receiving transducers may be used to receive the echoes of the volume ultrasound beams transmitted in step S100; etc. The receiving of the volume ultrasound beams and the obtaining of the volume ultrasound echo signals may be similar to those in the art.
When the volume ultrasound beams are transmitted in each of the ultrasound propagation directions in step S100, the echoes of the volume ultrasound beams may be received in step S200 to obtain a group of volume ultrasound echo signals. For example, when the echoes of the volume ultrasound beams transmitted to the scanning target in one ultrasound propagation direction in step S100 are received, a group of volume ultrasound echo signals may be obtained in step S200, and correspondingly the three-dimensional ultrasound image data of at least a part of the scanning target and the flow velocity vector information at the target points may be respectively obtained in step S300 and the step S400 based on the group of volume ultrasound echo signals. When the echoes of the volume ultrasound beams transmitted to the scanning target in multiple ultrasound propagation directions are received in step S200, multiple groups of volume ultrasound echo signals may be obtained, each of which may be derived from the echoes of the volume ultrasound beams transmitted in one ultrasound propagation direction. Then, correspondingly, in step S300 and the step S400, the three-dimensional ultrasound image data of at least a part of the scanning target may be obtained based on one of the multiple groups of volume ultrasound echo signals, and the flow velocity vector information at the target points may be obtained based on the multiple groups of volume ultrasound echo signals.
In addition, in the case that the volume ultrasound beams are transmitted in each of the ultrasound propagation directions for multiple times, the group of volume ultrasound echo signals obtained by receiving the echoes of the volume ultrasound beams in step S200 may include multiple ultrasound echo signals, where each of the ultrasound echo signals may be obtained by transmitting the ultrasound beams for one time.
For example, in the case that the volume plane ultrasound beams are transmitted to the scanning target in multiple ultrasound propagation directions in step S100, the echoes of the corresponding volume plane ultrasound beams in the multiple ultrasound propagation directions may be respectively received in step S200 to obtain multiple groups of volume plane ultrasound echo signals. Each group of volume plane ultrasound echo signals may include multiple volume plane ultrasound echo signals, and each of the multiple volume plane ultrasound echo signals may be derived from the echoes obtained by transmitting the volume plane ultrasound beams to the scanning target in one ultrasound propagation direction for one time.
As another example, in the case that the volume focused ultrasound beams are transmitted to the scanning target for multiple times in step S100, the echoes of the volume focused ultrasound beams may be received in step S200 to obtain multiple groups of volume focused ultrasound echo signals.
Therefore, the type of the echoes of the volume ultrasound beams received in step S200 and the number of the groups of the corresponding volume ultrasound echo signals may correspond to the type and the number of the transmitting of the volume ultrasound beams transmitted in step S100.
In step S300, the image processing unit 7 may obtain the three-dimensional image data of at least a part of the scanning target based on the volume ultrasound echo signals. Using three-dimensional imaging based on the volume ultrasound echo signals, the three-dimensional image data B1 and B2 as shown in
In some embodiments, the three-dimensional ultrasound image data may be obtained using the volume plane ultrasound beams, or may also be obtained using the volume focused ultrasound beams. However, since the energy of the volume focused ultrasound beam transmitted each time is more concentrated and the image data is obtained at the energy concentration position, the obtained echo signals may have high signal-to-noise ratio and the obtained three-dimensional ultrasound image data may have better quality. Furthermore, the volume focused ultrasound beams may have narrow main lobe and low side lobes, therefore the obtained three-dimensional ultrasound image data may have high lateral resolution. Therefore, in some embodiments, in step S500, the three-dimensional ultrasound image data may be obtained using the volume focused ultrasound beams. In addition, in order to obtain three-dimensional ultrasound image data with better quality, the volume focused ultrasound beams may be transmitted for multiple times in step S100 to obtain a frame of three-dimensional ultrasound image data.
Of course, the three-dimensional ultrasound image data may also be obtained based on the volume plane ultrasound echo signals obtained in step S200 above. In the case that multiple groups of volume ultrasound echo signals are obtained in step S200, one of the groups of volume ultrasound echo signals may be selected and used to obtain the three-dimensional ultrasound image data of at least a part of the scanning target.
In order to fully present the movement of the flow in spatial stereoscopic images, the step S300 may further include obtaining enhanced three-dimensional ultrasound image data of at least a part of the scanning target using grayscale blood flow imaging. The grayscale blood flow imaging may also be referred to as two-dimensional blood flow displaying, and is a new imaging method which may scan the blood flow, the blood vessels and the surrounding soft tissue using digital coded ultrasound technology and display the images in gray scale.
In the embodiments above, the processing to the three-dimensional ultrasound image data may be three-dimensional data processing performed on the whole three-dimensional ultrasound image data, or may also be a set of processing performed on one or more frames of two-dimensional ultrasound image data in one frame of three-dimensional ultrasound image data. Therefore, in some embodiments, the step S300 may include processing one or more frames of two-dimensional ultrasound image data in one frame of three-dimensional ultrasound image data using the grayscale blood flow imaging to obtained the enhanced three-dimensional ultrasound image data of the scanning target.
In step S400, the image processing unit 7 may obtain the flow velocity vector information at the target points in the scanning target based on the volume ultrasound echo signals obtained in step S200 above. The flow velocity vector information mentioned herein may include at least the velocity vectors (i.e. magnitude and direction of the velocity) at the target points, and may further include the location information of the target points in the spatial stereoscopic image. Of course, the flow velocity vector information may further include any other information related to the velocity at the target points which may be obtained based on the magnitude and direction of the velocity, such as acceleration information, etc.
For example, as shown in
As another example, in some embodiments, in step S400, a distribution density instruction inputted by the user may be obtained, target points may be selected randomly within the scanning target based on the distribution density instruction, and the flow velocity vector information at the selected target points may be calculated. The obtained flow velocity vector information may be marked on the background image (for example, the spatial stereoscopic image of the scanning target) for display on the stereoscopic display device. For example, for the object 210 and the object 220 in the part of the stereoscopic image in the
Then, the flow velocity vectors at the selected target points may be calculated, thereby obtaining the flow velocity vector information at the selected target points. The obtained flow velocity vector information may be marked on the spatial stereoscopic images of the scanning target for display on the stereoscopic display device.
As another example, In some embodiments, the step S400 may further include:
obtaining location marking instruction inputted by the user, obtaining the target points selected based on the location marking instruction, and calculating the flow velocity vector information at the selected target points. The obtained flow velocity vector information may be marked on the spatial stereoscopic images of the scanning target for display on the stereoscopic display device. For example, in
In the present embodiment, the target points may be selected by the user, and the two specific examples above provide two ways for selecting the target points, including selecting the locations of the target points or selecting initial positions used for calculating the flow velocity vectors at the target points. However, the present disclosure is not limited thereto. For example, the locations of the target points or the initial locations used for calculating the flow velocity vectors at the target points may be selected randomly in the scanning target based on the distribution density preset by the system. This way, the user may be provided with flexible selection methods, thereby increasing the user experience. Furthermore, based on the two methods for interacting with the user above, the distribution density instructions or the location marking instructions inputted by the user may be obtained by selecting the distribution density or the locations of target points through moving the stereoscopic cursor 230 displayed in the spatial stereoscopic images or through gestures. The configuration of the stereoscopic cursor 230 is not limited, and any configuration having stereoscopic sense of vision may be used. Furthermore, The stereoscopic cursor 230 may be distinguished from other marks used for marking the flow velocity vector information at the target points and from the background images (such as the images of tissue) using colors or shapes.
The process of obtaining the flow velocity vector information at the target points in the scanning target based on the volume ultrasound echo signals in step S400 will be described in detail below.
The flow velocity vector information obtained in step S400 may be mainly used to be superimposed on the spatial stereoscopic images. Therefore, based on different methods for displaying the flow velocity vector information, different flow velocity vector information may be obtained in step S400.
For example, in some embodiments, the step S400 may include calculating flow velocity vectors of the target point at a first display position in three-dimensional ultrasound image data at different times based on the volume ultrasound echo signals obtained in step S200 to obtain flow velocity vector information at the target point in the three-dimensional ultrasound image data at different times. Thereby, in subsequent step S500, the flow velocity vector information at the first location at the various times may be displayed on the spatial stereoscopic images. As shown in
In others embodiments of the present disclosure, the step S400 may include calculating flow velocity vectors successively generated continuous movement of the target point to corresponding positions in the spatial stereoscopic image based on the volume ultrasound echo signals obtained in step S200, thereby obtaining the flow velocity vector information of the target point. In the present embodiment, the corresponding flow velocity vectors at various corresponding positions during the continuous movement of the target point from the initial position may be obtained by successively calculating the flow velocity vector of the target moving from one position to another position in the spatial stereoscopic image in a time interval. That is, the calculation positions for determining the flow velocity vectors in the spatial stereoscopic image of the present embodiment may be obtained by calculation. Then, in step S500 below, what is displayed in superimposed manner may be the flow velocity vector information at the positions in the spatial stereoscopic image obtained by calculation at various times.
As shown in
In the display method of the present embodiment, the displacement of the target point in the time interval may be calculated, and the corresponding position of the target point in the three-dimensional ultrasound image data may be determined based on the displacement. The target point may be moved in the time interval starting from the position selected initially. The time interval may be determined based on the transmission frequency of the system, or based on display frame rate. Or, the time interval may also be inputted by the user. The position which the target point achieves after the movement may be calculated based on the time interval inputted by the user, and then the flow velocity vector information at such position may be obtained for display. Initially, N initial target points may be marked on the image as the methods shown in
Based on part or all of the target points selected by the user or by the system by default and the transmission form of the volume ultrasound beams in step S100, in the embodiments above, the following methods may be used to obtain the flow velocity vectors of the target points in the scanning target at the corresponding positions in the three-dimensional ultrasound image data at any time.
In the first method, one group of ultrasound echo signals obtained by transmitting the volume ultrasound beams in one ultrasound propagation direction in step S100 may be used to calculate the flow velocity vector information of the blood flow in the scanning target. In this process, the flow velocity vector of the target point at the corresponding position in the spatial stereoscopic image may be obtained by calculating the displacement and the movement direction of the target point in a preset time interval.
As described above, in the present embodiment, the volume plane ultrasound echo signals may be used to calculate the flow velocity vector information of the target point. Therefore, in some embodiments, the displacement and direction of the movement of the target point in the scanning target in the preset time interval may be calculated based on one group of volume plane ultrasound echo signals.
In the present embodiment, speckle tracking may be used to calculate the flow velocity vectors of the target point at the corresponding position in the spatial stereoscopic image. Alternatively, Doppler ultrasound imaging may be used to obtain the flow velocity vector of the target point in an ultrasound propagation direction. And alternatively, the velocity vector components of the target point may be obtained based on the time gradient and the spatial gradient at the target point.
For example, in some embodiments, obtaining the flow velocity vectors of the target point in the scanning target at the corresponding position in the spatial stereoscopic image based on the volume ultrasound echo signals may include following steps.
First, at least two frames of three-dimensional ultrasound image data may be obtained based on the obtained volume ultrasound echo signals. For example, at least a first frame of three-dimensional ultrasound image data and a second frame of three-dimensional ultrasound image data may be obtained.
As described above, in the present embodiment, the volume plane ultrasound beams may be used to obtain the image data used for calculating the flow velocity vectors of the target point. The volume plane ultrasound beams may substantially propagate in the entire imaging area. Therefore, one frame of three-dimensional ultrasound image data may be obtained by transmitting a group of volume plane ultrasound beams which have the same angle using a two dimensional array probe, receiving the echoes and performing three-dimensional imaging process. In case that the frame rate is 10000, i.e. 10000 transmissions per second, 10000 frames of three-dimensional ultrasound image data may be obtained in each second. In the present disclosure, the three-dimensional ultrasound image data of the scanning target obtained by processing the volume plane beam echo signals of the volume plane ultrasound beams may be referred to as “volume plane beam echo image data.”
Thereafter, a three-dimensional tracking area may be selected in the first frame of three-dimensional ultrasound image data. The three-dimensional tracking area may contain the target points of which the velocity vectors are desired to be obtained. In one embodiment, the three-dimensional tracking area may be a three-dimensional area with any shape centered at the target point, such as a cube area.
Then, a three-dimensional area corresponding to the three-dimensional tracking area may be searched out from the second frame of three-dimensional ultrasound image data. For example, a three-dimensional area which has maximum similarity with the three-dimensional tracking area may be searched out as a tracking result area. The measurement of the similarity herein may be common measurements in the art.
At last, the velocity vectors of the target point may be obtained based on the positions of the three-dimensional tracking area and the tracking result area above and the time interval between the first and second frame of three-dimensional ultrasound image data. For example, the magnitude of the flow velocity vector may be obtained by dividing the distance between the three-dimensional tracking area and the tracking result area (i.e. the displacement of the target point within the preset time interval) by the time interval between the first and second frame of volume plane beam echo image data, and the direction of the flow velocity vector may be the direction of a line extending from the three-dimensional tracking area to the tracking result area, i.e. the moving direction of the target point within the preset time interval.
In order to increase the accuracy of the calculation of the flow velocity vector using the speckle tracking, wall filtering may be performed on each frame of three-dimensional ultrasound image data, i.e., the wall filtering may be performed in the time direction for each spatial point in the three-dimensional ultrasound image data. The signals representing the tissue in the three-dimensional ultrasound image data have small changes over time, while the signals representing the flow such as the blood flow have large changes. Therefore, a high-pass filter may be used as the wall filter for the flow signals such as the signals representing the blood flow. After the wall filtering, the signals representing the flow with high frequency are retained, while the signals representing the tissue with low frequency are filtered out. In the wall-filtered signals, the signal to noise ratio of the signals representing the flow is greatly increased, which helps to increase the accuracy of the calculation of the flow velocity vector. In the present embodiment, the wall filtering performed on the obtained three-dimensional ultrasound image data may also be suitable for other embodiments.
In one embodiment, obtaining the velocity vector of the target point based on the time gradient and the spatial gradient at the target point may include following steps.
First, at least two frames of three-dimensional ultrasound image data may be obtained based on the volume ultrasound echo signals. Alternatively, the wall filtering may additionally be performed on the three-dimensional ultrasound image data.
Then, the gradient in the time direction of the target point may be obtained based on the three-dimensional ultrasound image data, and a first velocity component of the target point in the ultrasound propagation direction may be obtained based on the three-dimensional ultrasound image data.
Thereafter, a second velocity component in a first direction and a third velocity component in a second direction at the target point may be obtained based on the gradient and the first velocity component, where the first direction, the second direction and the ultrasound propagation direction are perpendicular to each other.
Finally, the first velocity component, the second velocity component and the third velocity component may be synthesized to obtain the flow velocity vector of the target point.
In the present embodiment, the first direction, the second direction and the ultrasound propagation direction are perpendicular to each other, which may be considered as a three-dimensional coordinate system in which the ultrasound propagation direction is one of the coordinate axes. For example, the ultrasound propagation direction may be Z axis, and the first direction and the second direction may be X axis and Y axis.
Assuming that the wall-filtered three-dimensional ultrasound image data is represented as P(x(t),y(t),z(t)), the formula (1) may be obtained according to the chain rule by finding the derivative of P along the time direction:
The second velocity component of the flow in X direction is represented as
the third velocity component in Y direction is represented as
and the first velocity component in Z direction is represented as
Accordingly, the formula (1) may be transformed into formula (2):
Where
may be obtained by calculating the gradients of the three-dimensional ultrasound image data in X, Y and Z direction, respectively, and
may be obtained by calculating, for each spatial point in the three-dimensional ultrasound image data, the gradient in the time direction based on multiple frames of three-dimensional ultrasound image data.
Thereafter, using the least squares solution, the formula (2) may be transformed into a linear regression equation formula (3):
Where the subscript i in
may represent the ith calculation of the gradient of the three-dimensional ultrasound image data in X, Y and Z directions. The gradients of the spatial points in the three coordinate axes calculated in multiple times may form a parameter matrix A. It is assumed that the gradients are calculated for N times, and it is also assumed that the flow velocity remains constant for this period of time since the time taken by the N calculations is very short. εi represents random error. Herein, the formula (3) satisfies Gauss-Markov theorem, and its solution is the formula (4) below:
Where the parameter
According to the Gauss-Markov theorem, the variance of the random error εi may be represented as the formula (5) below:
var(εi)=σA2 (5)
Based on the relationship model of the gradient, the velocity values VZ and the average thereof at each spatial point in the ultrasound propagation direction (i.e. Z direction) at different times may be obtained according to Doppler ultrasound measurement, and the variance of the random error and the parameter matrix at each spatial point in the ultrasound propagation direction may be calculated. VD is a group of velocity value at different times obtained by Doppler ultrasound measurement, and vZ in the formula (6) is the average obtained by the Doppler ultrasound measurement.
The variance of the random error εi based on the formula (3) may be represented as the formula (7) below.
var(εj)−σB2 (7)
Two different variances may be calculated using the formula (5) and (7). The formula (3) above may be solved using weighted least squares method utilizing the variance of the random error and the parameter matrix at each spatial point in the ultrasound propagation direction as known information, as shown by the formula (8) below.
Where the weighting factor
O is zero matrix, and IA and IB are unit matrixes, the orders of which respectively correspond to the numbers of rows of the matrix A and matrix B. The weighting factor may be the square root of the reciprocal of the variance of the random error in the linear error equation.
After three velocities vx, vy and vz which are perpendicular to each other are obtained, the magnitude and direction of the vector flow velocity by three-dimensional spatial fitting.
In one embodiment, Doppler ultrasound imaging may be used to obtain the flow velocity vector of the target point, as described below.
In the Doppler ultrasound imaging method, the ultrasound beams may be successively transmitted to the scanning target multiple times in an ultrasound propagation direction. The echoes of the transmitted ultrasound beams may be received to obtain multiple volume ultrasound echo signals. Each value in each volume ultrasound echo signal may correspond to a value at one target point when scanning the scanning target in an ultrasound propagation direction. Step S400 may include following steps.
A Hilbert transform along the ultrasound propagation direction or an IQ demodulation may be performed on the multiple volume ultrasound echo signals. After the beamforming, multiple three-dimensional ultrasound image data may be obtained, which may represent the value at each target point using complex number. After N transmissions and receptions, there are N complex numbers at each target point which vary over time. Thereafter, the magnitude of the velocity of a target point z in the ultrasound propagation direction may be calculated according to the following two formulas:
Where Y is the calculated velocity value in the ultrasound propagation direction, c is velocity of sound, f0 is the center frequency of the probe, Tprf is the time interval between two transmissions, N is the number of the transmission, x(i) is the real part corresponding to the ith transmission, y(i) is the imaginary part corresponding to the ith transmission, is the imaginary part operator, and is the real part operator. The formula above may be used to calculate the flow velocity at a fixed position.
Similarly, the magnitude of the flow velocity vector at each target point may be calculated using the N complex numbers.
The direction of the flow velocity vector may be the ultrasound propagation direction, i.e. the ultrasound propagation direction corresponding to the multiple volume ultrasound echo signals.
Generally, in ultrasound imaging, the moving velocity of the scanning target, or of the moving part thereof, may be obtained by performing Doppler processes on the volume ultrasound echo signals based on Doppler principle. For example, after the volume ultrasound echo signals are obtained, the moving velocity of the scanning target, or of the moving part thereof, may be obtained based on the volume ultrasound echo signals using autocorrelation estimation or cross correlation estimation. The method for Doppler-processing the volume ultrasound echo signals to obtain the moving velocity of the scanning target, or of the moving part thereof, may be any method being or to be used by which the moving velocity of the scanning target, or of the moving part thereof, may be calculated based on the volume ultrasound echo signals, and will not be described in detail.
Of course, for the volume ultrasound echo signals corresponding to an ultrasound propagation direction, it will not be limited to the two methods above. Other methods known or to be used in the art may also be used.
In the second method, multiple groups of volume ultrasound echo signals may be obtained by transmitting the volume ultrasound beams in multiple ultrasound propagation directions in step S100 and receiving the echoes of the volume ultrasound beams from multiple scanning bodies. The multiple groups of volume ultrasound echo signals may be used to calculate the flow velocity vector information of the target point in the scanning target. In this process, one velocity vector component at the position in the spatial stereoscopic image corresponding to the target point in the scanning target may be calculated based on one group of volume ultrasound echo signals of the multiple groups of volume ultrasound echo signals, and accordingly multiple velocity vector components at the corresponding position may be obtained based on the multiple groups of volume ultrasound echo signals. And then, the flow velocity vector at the corresponding position of the target point in the spatial stereoscopic image may be synthesized based on the multiple velocity vector components.
As described above, in the present embodiment, the volume plane ultrasound echo signals may be used to calculate the flow velocity vector of the target point. Therefore, in one embodiment, one velocity vector component of the target point in the scanning target at one position may be calculated based on one group of volume plane ultrasound echo signals of multiple groups of volume plane ultrasound echo signals, and accordingly multiple velocity vector components at such position may be obtained based on the multiple groups of volume plane ultrasound echo signals.
In the present embodiment, the methods for calculating one velocity vector component of the target point in the scanning target based on one of the multiple groups of volume ultrasound echo signals may be similar to those in the first method. For example, the velocity vector component of the target point at corresponding position may be obtained by calculating the displacement and moving direction of the target point in a preset time interval based on one group of volume ultrasound echo signals. In the present embodiment, the speckle tracking as described above may be used to calculate the velocity vector component of the target point. Alternatively, Doppler ultrasound imaging may also be used to obtain the velocity vector component of the target point in an ultrasound propagation direction. Alternatively, the blood flow velocity vector component of the target point may be obtained based on the time gradient and the spatial gradient at the target point. Reference may be made to the detailed description of the first method above for details.
In the case that there are two angles in step S100, the magnitudes and directions of the flow velocities at all position to be measured at one moment may be obtained through 2N transmissions; in the case that there are three angle, 3N transmissions are needed; and so on. In
In the case that there are at least three ultrasound propagation directions in step S100, the at least three ultrasound propagation directions corresponding to the at least three groups of echo signals used for calculating at least three velocity vector components may not be in a same plane, such that the calculated flow velocity vector is closer to the velocity vector in real three-dimensional space. This condition may be referred to as constraint related to ultrasound propagation direction.
For example, in step S100 above, the volume ultrasound beams may be transmitted to the scanning target in N (3≦N) ultrasound propagation directions; while in step S400, n velocity vector components may be used to calculate the flow velocity vector of the target point at corresponding position each time, where herein 3≦n<N . I.e., in step S100, the volume ultrasound beams may be transmitted to the scanning target in at least three ultrasound propagation directions, where the adjacent at least three ultrasound propagation directions are not in a same plane. Accordingly, in step S400, at least three blood flow velocity vector components of the target point at the corresponding position corresponding to at least three groups of volume echo signals received successively may be respectively calculated, where one velocity vector component of the target point in the scanning target is calculated based on one of the at least three groups of volume echo signals. The flow velocity vector of the target point at the corresponding position may be synthesized based on the velocity vector components in the at least three ultrasound propagation directions.
In order to reduce the amount of calculation and the complexity of the scanning and calculation, it is also possible that in step S100 the volume ultrasound beams are transmitted to the scanning target in N (3≦N) ultrasound propagation directions while in step S400 N velocity vector components are used to calculate the flow velocity vector of the target point at the corresponding position each time. I.e., in step S100, the volume ultrasound beams may be transmitted to the scanning target in at least three ultrasound propagation directions, where the at least three ultrasound propagation directions are not in a same plane. Accordingly, in step S400, the velocity vector components of the target point at the corresponding position in all of the ultrasound propagation directions corresponding to the at least three groups of volume echo signals may be respectively calculated, where one velocity vector component of the target point in the scanning target is calculated based on one of the received at least three groups of volume echo signals. The flow velocity vector of the target point at the corresponding position may be synthesized based on the velocity vector components in all of the ultrasound propagation directions.
In order to satisfy the constraint related to ultrasound propagation direction, both “the adjacent at least three ultrasound propagation directions being not in a same plane” and “the at least three ultrasound propagation directions being not in a same plane” may be implemented by adjusting the time delay of the transducers used for the transmission of the ultrasound beams and/or driving the transducers used for the transmission of the ultrasound beams to steer to change the emission direction of the ultrasound waves in order to obtain different ultrasound propagation directions. Herein, driving the transducers used for the transmission of the ultrasound beams to deflect to change the emission direction of the ultrasound waves may be implemented by, e.g., providing drive control device for each linear probe or each transducer in the probe group arranged in array and adjusting the steering angle or time delay of the probes or transducers in the probe group such that the scanning bodies formed by the volume ultrasound beams transmitted by the probe group have different steering amount, thereby obtaining different ultrasound propagation directions.
In some embodiments, user-selectable items, or user-selectable buttons, may be provided on the display interface, by which the user may select the number of the ultrasound propagation directions or the number of the velocity vector components used for the synthesis of the flow velocity vector in step S400 above, and thereby instruction information may be generated. Based on the instruction information, the number of the ultrasound propagation directions in step S100 above may be adjusted and the number of the velocity vector components used for the synthesis of the flow velocity vector may be determined according to the number of the ultrasound propagation directions, and alternatively the number of the velocity vector components used for the synthesis of the flow velocity vector of the target point at the corresponding position in step S400 may be adjusted, thereby providing more comfortable experience and more flexible information extraction interface for the user.
In step S500, the stereoscopic display device 8 may display the obtained three-dimensional ultrasound image data to form a spatial stereoscopic image of the scanning target and superimpose the flow velocity vector information on the spatial stereoscopic image. In the present disclosure, the spatial stereoscopic image may be displayed in real-time or non-real-time. In the cast that it is displayed in non-real-time, a plurality of frames of three-dimensional ultrasound image data within a period of time may be cached in order to perform image playback control operations, such as slow play or quick play, etc.
In the present embodiment, holographic display techniques or volume three-dimensional display techniques may be used to display the three-dimensional ultrasound image data to form the spatial stereoscopic image of the scanning target and superimpose the flow velocity vector information on the spatial stereoscopic image.
The hologram herein may include traditional hologram (transmission hologram, reflective hologram, image plane hologram, rainbow hologram or synthetic hologram, etc.) and computer generated hologram (CGH). The CGH may float in the air and have a wide color gamut. In the CGH, a mathematical model of the object whose hologram will be generated may be built, and the physical interference of light waves may be replaced by the calculation steps. In each step, the strength graphics of the CGH model may be determined, and may be outputted to a reconfigurable device. This device may re-modulate the light wave information and reconstruct the output. In general, in CGH, the computer may obtain an interference pattern of a computer graphics (virtual object), which will replace the interference process of the light waves of the object in traditional hologram, through calculation. The diffraction process of the hologram reconstruction may not change in principle, but only device which can reconfigure the light wave information is added, thereby achieving the holographic display of different computer static, dynamic graphics.
In some embodiments using the holographic display techniques, as shown in
As an alternative to the holographic imaging system, the stereoscopic display device 8 may also form the stereoscopic image on air, special lenses, fog screen or the like using a holographic projection device. Accordingly, the stereoscopic display device 8 may also be an air holographic projection device, a laser beam holographic projection device, a holographic projection device with 360 degree holographic display (in which the images are projected to a high-speed rotating minor to obtain the hologram) or a fog screen stereoscopic imaging system, etc.
The air holographic projection device may project the interference pattern of the computer graphics (virtual object) obtained in the embodiments above on an airflow wall to form the spatial stereoscopic image. Since the vibration of the water molecules of the water vapor is not balanced, a hologram with strong three-dimensional sense may be formed. Accordingly, in the present embodiment, a device used for forming the airflow wall may be added based on the embodiment shown in
The laser beam holographic projection device may use laser beam to project an object. In one embodiment, the laser beam holographic projection device may project the interference pattern of the computer graphics (virtual object) obtained in the embodiments above through laser beams to obtain the spatial stereoscopic image. In the present embodiment, the laser beam projection device may form the hologram through continuous small explosions in the air and the hot substances converted from mixture of oxygen and nitrogen spreading out in the air.
The fog screen stereoscopic imaging system may further include an atomization device based on the embodiment shown in
Some holographic display devices have been simply described, and their specific configuration may be similar to related device existing in the market. However, the present disclosure will not be limited to the holographic display devices or systems described above. Other holographic display devices or techniques developed in the future may also be used.
The volume three-dimensional display techniques may form a display object in which the molecular particles are replaced by voxel particles utilizing the special visual mechanism of human. Not only the shape represented by the light waves can be observed, but also the real existence of the voxels can be sensed. The volume three-dimensional display techniques may excite the substances within a transparent display volume and form the voxels utilizing the absorption or scattering of the visible radiation. When the substance within the volume at many directions are excited, the three-dimensional spatial image formed by many voxels dispersed in the three-dimensional space can be obtained. The volume three-dimensional display techniques may include two kinds of techniques below.
(1) Rotating body scanning technique. The rotating body scanning technique may be used for displaying moving object. According to this technique, a series of two dimensional images may be projected to a rotating or moving screen while this screen is moving in a speed which the observer can not perceive. Because of the visual persistence of human, three-dimensional object may be formed by human eye. Therefore, the display system using such stereoscopic displaying techniques can achieve a real three-dimensional display (visible in 360 degree) of the images. In such system, the light beams with different color may be projected on the display media through light deflectors such that the media can present rich colors. Furthermore, such media can enable the light beam to generate discrete visible spots. These spots are voxels and correspond to the points in the three-dimensional image. The groups of voxels may form an image, and the observer can observe this real three-dimensional image from any point of view. The imaging space of the display device using the rotating body scanning techniques may be generated by the rotation or displacement of the screen. The voxels may be activated on the transmission surface when the screen sweeps through the imaging space. The system may include a laser system, a computer control system and a rotation display system, etc.
In some embodiments using the volume three-dimensional display techniques, as shown in
In other embodiments of the present disclosure, in the configuration shown in
As shown in
(2) Static volume imaging techniques. The static volume imaging techniques may form a three-dimensional stereoscopic image based on frequency conversion techniques. In frequency conversion three-dimensional stereoscopic display, the media in the imaging space may spontaneously emit fluorescence after absorbing multiple photons, thereby generating the visible voxels. The basic principle may be described herein. Two infrared lasers perpendicular to each other may be acted crosswise on the conversion material. After two resonance absorption by the conversion material, the electrons in the emission center may be excited to high excitation level. When the electrons jump to lower level, the emission of visible light may occur. Therefore, one point in the space of the conversion material may be a bright spot which emits light. When the intersection of the two lasers are swept in the three-dimensional space of the conversion material according to a certain trajectory, the path through which the intersection of the two lasers has passed will be a bright band which can emit visible fluorescence, i.e., a three-dimensional stereoscopic graphic which is the same with the movement trajectory of the intersection of the lasers. With this method, a three-dimensional stereoscopic image which can be observed omni-directionally in 360 degree can be observed by naked eye. According to the static volume imaging techniques, display media may be arranged in the voxel entity part 811 in the embodiments above. The media may be formed by a plurality of LCD screens which are arranged with intervals and in a stacked manner (for example, the resolution of each screen may be 1027×748 and the interval between the screens may be about 5 mm). The liquid crystal pixels of these special LCD screens may have special electronic control optical properties. When the voltage is applied to them, the liquid crystal pixel will become parallel to the light beam propagation direction, like the foliages of the blind, such that the light beams irradiating such liquid crystal pixel will pass through. When the voltage applied to them is zero, the liquid crystal pixel will become opaque, thereby diffusely reflecting the irradiating light beams to form a voxel existing in the stacked LCD screens. In this case, the rotation motor in
Some volume three-dimensional display devices have been described above, and their specific configuration may be similar to related device existing in the market. However, the present disclosure will not be limited to the devices or systems based on volume three-dimensional display techniques described above. Other volume three-dimensional display techniques developed in the future may also be used.
In the present embodiment, the spatial stereoscopic image of the scanning target may be displayed in a certain space or any space, or be represented through the display media such as air, mirrors, fog screens or rotating or resting voxels, etc. Accordingly, In some embodiments, the flow velocity vector information of the target points obtained using the first mode may be superimposed on the spatial stereoscopic image displayed through the methods above, as shown in
In addition, in some embodiments, the flow velocity vector information of the target points obtained using the second mode above may be superimposed on the spatial stereoscopic image displayed using the methods above, i.e., the flow velocity vector information of the target point may include the flow velocity vectors which are accordingly obtained when the target point successively moves to the corresponding positions in the spatial stereoscopic image, and in step S500, the flow velocity vectors correspondingly obtained when the target point successively moves to the corresponding positions may be displayed to form the flow velocity vector mark which flows over time. As shown in
As shown in
Furthermore, in order to highlight the flow velocity vector information in the spatial stereoscopic image, the contour lines of the stereoscopic image regions of the tissues may be displayed so as to avoid covering or confusing the flow velocity vector marks. For example, as shown in
As shown in
Furthermore, one or more of the color and shape of the flow velocity vector marks (920, 940, 973, 962, 981, 982) used for representing the flow velocity vector information in the spatial stereoscopic image may be set so as to distinguish the velocity levels and directions of the displayed flow velocity vector information. For example, the flow velocity vector marks in arteries may use red colors which are gradually changed with respect to each other to represent the different velocity levels, while the flow velocity vector marks in veins may use green colors which are gradually changed with respect to each other to represent the different velocity levels. The deep red color or the deep green color may represent the high velocity, and the light green color or the light red may represent the low velocity. The specific methods for configuring the colors may be those known in the art and will not be described in detail.
In addition, in the embodiments above, the flow velocity vector mark may include the three-dimensional marker with arrow or direction indicator, such as the cube with arrow in
Alternatively, the flow velocity vector mark may also be a three-dimensional marker without arrow or direction indicator, such as the sphere shown in
Alternatively, the rotation speed of the three-dimensional marker may be used to represent the magnitude of the flow velocity vector, and the direction of the arrow may be used to represent the direction of the flow velocity vector. Accordingly, the present disclosure will not be limited to the methods for representing the magnitude or direction of the flow velocity vector described above. In the present disclosure, the size or rotation speed of the three-dimensional marker used for marking the flow velocity vector of the target point may be used to represent the magnitude of the flow velocity vector and/or the direction of the arrow or indirection indicator of the three-dimensional marker or the movement of the three-dimensional marker over time may be used to represent the direction of the flow velocity vector.
In addition, as shown in
Furthermore, color information may be superimposed on the cluster block regions like cloud so as to more clearly display the cluster blocks. For example, when the blood vessel wall is displayed with red color, white color, or orange-red color may be superimposed on the cluster block regions representing the blood flow for distinguish. Alternatively, in the step of segmenting the region of interest representing the flow area in the enhanced three-dimensional ultrasound image data to obtain the cluster block region like cloud, the region of interest representing the flow area in the enhanced three-dimensional ultrasound image data may be segmented based on the grayscale of image, thereby obtaining the cluster block regions with different grayscale characteristics. For the cluster block regions in the spatial stereoscopic space, the grayscale characteristics herein may be the mean, maximum or minimum of the grayscale values of the spatial points in the whole region, or one or more other values which can represent the grayscale characteristics of the whole region. In the step of displaying the cluster block regions lick cloud in the spatial stereoscopic image, the cluster block regions with different grayscale characteristics may be rendered with different colors. For example, assuming the cluster block regions obtained by the segmentation can be classified into 0-20 class based on the grayscale characteristics, each class may be displayed with one color. Alternatively, the 0-20 class may also be displayed using tints with different purity which belong to a same color, respectively.
As shown in
Based on the display of the cloudy cluster block regions described above, another display mode is actually provided. As shown in
In some embodiment of the present disclosure, the flow velocity vector information of the target point obtained using the second mode described above may be superimposed on the spatial stereoscopic image displayed using the methods above. The flow velocity vector information of the target point may include the flow velocity vectors correspondingly obtained when the target point successively move to correspondingly positions in the spatial stereoscopic image. In step S500, an connection mark connecting the multiple positions (such as tow or more positions) in the spatial stereoscopic image to which one target point has moved may be formed to represent the movement trajectory of the target point, and be displayed in the spatial stereoscopic image. In
In some embodiments, in order to facilitate the highlight display of the movement trajectory in the spatial stereoscopic image, the method described above may further include following steps.
First, indication information of the connection mark inputted by the user may be obtained to generate a selection instruction. The indication information may include the shape of the connection mark or the shape and color of the connection line, etc. And then, the parameters of the connection mark used for displaying the movement trajectory in the spatial stereoscopic image may be configured according to the indication information selected by the selection instruction.
In the present disclosure, the color may include any color obtained by adjusting the tint (hue), saturation (purity) or contrast, etc. The connection mark may be implemented in many forms, such as slender cylinder, segmental slender cylinder or comet tail-like mark or any other mark which can represent the direction.
Furthermore, based on the display of the movement trajectory of the target point, another display mode is actually provided by the present disclosure. As shown in
In addition, the movement trajectory of one or more target points may be displayed, and the initial position may be obtained by inputted instructions. For example, distribution density instruction inputted by the user may be obtained, and the target point may be randomly selected in the scanning target according to the distribution density instruction. Alternatively, the position indication instructions inputted by the user may be obtained, and the target points may be determined according to the position indication instructions.
In the description of the embodiments above, only the implementation of corresponding steps is described. However, as long as there is no contradiction in logic, the embodiments above may be combined with each other to form new technical solutions, which will be still within the scope of the disclosure of the embodiments.
With the description of the embodiments above, a person skilled in the art will understand that the methods described in the embodiments above can be implemented by software and general hardware platforms, or be implemented by hardware. But in many cases, the former may be preferred. Based on this understanding, the essence or the parts contributing to the prior art of the present disclosure may be implemented as software products. The software products may be carried by a nonvolatile computer readable storage media (such as ROM, disk, CD or server cloud), and may include several instructions which, when be executed, can enable a terminal equipment (which may be a mobile phone, a computer, a sever or a network device, etc.) to perform the methods of the embodiments of the present disclosure.
Based on the ultrasound imaging methods described above, the present disclosure may further provide an ultrakmnd imaging system, which may include: a probe 1; a transmitting circuit 2 which may excite the probe to transmitting volume ultrasound beams to the scanning target; a receiving circuit 4 and a beam forming unit 5 which may receive the echoes of the volume ultrasound beams and obtain volume ultrasound echo signals; a data processing unit 9 which may obtain the three-dimensional ultrasound image data of at least a part of the scanning target based on the volume ultrasound echo signals, and may obtain the flow velocity vector information of the target point in the scanning target based on the volume ultrasound echo signals; and a stereoscopic display device 8 which may receive the three-dimensional ultrasound image data and the flow velocity vector information of the target point, display the three-dimensional ultrasound image data to form the spatial stereoscopic image of the scanning target, and display the flow velocity vector information on the spatial stereoscopic image.
The transmitting circuit 2 may perform step S100 above, and the receiving circuit 4 and the beam forming unit 5 may perform S200 above. The data processing unit 9 may include a signal processing unit 6 and/or an image processing unit 7. The signal processing unit 6 may perform the calculation of the velocity vector components and the flow velocity vector information described above, i.e. step S400 above. The image processing unit 7 may perform the image processing processes described above, i.e. step S300 of obtaining the three-dimensional ultrasound image data of at least a part of the scanning target according to the volume ultrasound echo signals obtained in the preset time period. The image processing unit 7 may further output the data including the three-dimensional ultrasound image data and the flow velocity vector information to the stereoscopic display device 8 for display. The performance of the functional units may be similar to the steps of the ultrasound imaging methods described above and will not be described again.
In some embodiments of the present disclosure, the stereoscopic display device 8 may further mark the flow velocity vectors obtained when the target point successively moves to the corresponding positions to form the flow velocity vector mark flowing over time. The specific performance may be similar to those described above.
In some embodiments, the echo signals of the volume plane ultrasound beams may be used to calculate the flow velocity vector components and flow velocity vector information and the three-dimensional ultrasound image data. For example, the transmitting circuit may excite the probe to transmit the volume plane ultrasound beams to the scanning target; the receiving circuit and the beam forming unit may receiving the echoes of the volume plane ultrasound beams and obtain the volume plane ultrasound echo signals; and the data processing unit may obtain the three-dimensional ultrasound image data of at least a part of the scanning target and the flow velocity vector information of the target point according to the volume plane ultrasound echo signals.
Alternatively, the echo signals of the volume plane ultrasound beams may be used to calculate the velocity vector components and the flow velocity vector information, while the echo signals of the volume focused ultrasound beams may be used to obtain the ultrasound images with high quality. Accordingly, the transmitting circuit may excite the probe to transmit the volume focused ultrasound beams to the scanning target; the receiving circuit and the beam forming unit may receive the echoes of the volume focused ultrasound beams and obtain the volume focused ultrasound echo signals; and the data processing unit may obtain the three-dimensional ultrasound image data of at least a part of the scanning target according to the volume focused ultrasound echo signals. Furthermore, the transmitting circuit may excite the probe to transmit the volume plane ultrasound beams to the scanning target, where the transmission of the volume focused ultrasound beams to the scanning target may be inserted between the transmissions of the plane ultrasound beams to the scanning target; the receiving circuit and the beam forming unit may receive the echoes of the volume plane ultrasound beams and obtain the volume plane ultrasound echo signals; and the data processing unit may obtain the flow velocity vector information of the target point in the scanning target according to the volume plane ultrasound echo signals. The alternate transmission of the two kinds of beams may be similar to those described above, and will not be described in detail again.
Furthermore, the data processing unit may further obtain the enhance three-dimensional ultrasound image data of at least a part of the scanning target using the grayscale blood flow imaging according to the volume ultrasound echo signals, and obtain the cluster block regions like cloud by segmenting the region of interest in the enhance three-dimensional ultrasound image data representing the flow area. The stereoscopic display device may further display the cloudy cluster block regions in the displayed spatial stereoscopic image to form the cluster blocks rolling over time. The specific implementation may be similar to those described above.
Alternatively, in some embodiments, as shown in
The steps performed by the data processing unit 9 according to the instructions inputted by the user may be similar to those described above and will not be described in detail again.
The stereoscopic display device 8 may include one of the holographic display device based on holographic display techniques and voxel display device based on volume three-dimensional techniques. The specific configuration may be similar to those described with respect to S500 above, as shown in
In some embodiment of the present disclosure, the human-machine interface device may include an electronic device 840 which is connected with the data processing unit and provided with a touch screen. The electronic device 840 may be connected with the data processing unit 9 through a communication interface (wireless or wired communication interface) so as to receive the three-dimensional ultrasound image data and the flow velocity vector information of the target point, and display them on the touch screen to present the ultrasound image (which may be two dimensional or three-dimensional ultrasound image based on the three-dimensional ultrasound image data) and the flow velocity vector information superimposed on the ultrasound image. The electronic device 840 may further receive the operation instructions inputted by the user through the touch screen and transfer the operation instructions to the data processing unit 9. The operation instructions herein may include one or more instructions inputted by the user with respect to the data processing unit 9 described above. The data processing unit 9 may obtain related configuration or switch instructions according to the operation instructions and transfer them to the stereoscopic display device 800. The stereoscopic display device 800 may adjust the display of the spatial stereoscopic image according to the configuration or switch instructions so as to synchronously display, in the spatial stereoscopic image, the results of the controls such as image rotation, image parameter configuration, image display mode switch or the like performed according to the operation instructions inputted by the user through the touch screen. As shown in
Furthermore, in some embodiments, the human-machine interface device 10 may also be physical operation key (such as keyboard, operating lever or roller, etc), virtual keyboard or gesture input device with camera, etc. The gesture input device herein may include a device which may acquire the image when the gesture is inputted and track the gesture input using image recognition techniques. For example, the device may use an infrared camera to acquire the image of the gesture input and obtain the operation instructions represented by the gesture input using the image recognition techniques.
Accordingly, the present disclosure provides ultrasound flow imaging methods and ultrasound imaging systems which can, overcoming the drawbacks of existing ultrasound imaging system in displaying the blood flow, be suitable for imaging and displaying the blood flow. The systems may provide better observation perspective to the user through the 3D stereoscopic display techniques. Not only the scanning position can be observed in real time, but also the blood flow information can be presented more realistically by the image. The movement of the fluid in the scanning target may be reproduced really, multiple-angle, omni-directional observation can be provided to the user, and more comprehensive, more accurate image data can be provided to medical personnel. Accordingly, a new display method for blood flow imaging may be created for achieving blood flow display in ultrasound systems. In addition, the present disclosure further provides new methods for calculating the flow velocity vector information of the target point, which can provide more real data regarding the actual flow state of the fluid and intuitively present the movement trajectory of the target point along the flow direction. Furthermore, the present disclosure further provides more personalized custom services, and provides more accurate, more intuitive data support for the user observing the real flow state.
The present disclosure further provides display methods which can present grayscale enhancement effect in the ultrasound stereoscopic image. In the methods, different colors may be used to represent the image of the region of interest with change in grayscale, and the flow state of the cluster block regions may be dynamically presented. Compared with the traditional display, the 3D display of the present disclosure is more vivid and more real, and contains more information.
Several embodiments of the present disclosure have been described above, which is relatively specific and detailed. However, it can not be interpreted as limitation to the scope of the present disclosure. It should be noted that, for a person of ordinary skill in the art, many modifications, improvements and combination can be made without departing from the concepts of the present disclosure, all of which are within the scope of the present disclosure. Therefore, the protection scope of the present disclosure should be determined by the appended claims.
Number | Date | Country | |
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Parent | PCT/CN2015/080934 | Jun 2015 | US |
Child | 15827991 | US |