Abstract:
An ultrasound imaging console includes receive circuitry that receives a set of echoes produced in response to an ultrasound signal traversing blood flowing in a portion of a vessel in a field of view, a beamformer that beamforms the echoes, a velocity processor that determines flow direction and magnitude of the flowing blood based on the beamformed echoes, and a rendering engine that displays the determined flow direction and magnitude.

Description:
TECHNICAL FIELD 
       [0001]    The following generally relates to ultrasound imaging and more particularly to vector flow ultrasound imaging. 
       BACKGROUND 
       [0002]    Ultrasound imaging provides information about the interior of a subject. For example, ultrasound imaging can be used to generate an image of a blood vessel and estimate blood flow velocity inside the blood vessel. 
         [0003]    With conventional blood flow velocity estimation, a pulse-echo field oscillates in the axial direction along the axis of the ultrasound beam. This is illustrated in  FIG. 1  in which a transducer array  100  produces an ultrasound beam  102  that propagates in the axial direction along the z-axis (or depth)  104 . Blood scatterers passing through the field of interest produce a signal with a frequency component proportional to the axial velocity, and the axial velocity component (VZ)  106  can be estimated. 
         [0004]    The transverse oscillation (TO) blood velocity estimation approach has been used to estimate both VZ  106  and the transverse velocity component (VX)  108 , along the transverse axis  110 , of the velocity vector  112 . With the transverse oscillation approach, a transverse oscillation is introduced in the ultrasound field, and this oscillation generates signals that depend on the transverse oscillation. The basic idea is to create a double-oscillating pulse-echo field using a one dimensional (1D) transducer array. 
         [0005]    Color flow mapping (CFM) is one approach to visually show velocity. An example of this is shown in  FIG. 2 , in which first flow  202  through a first vessel  204  and second flow  206  through a second vessel  208  towards the transducer is displayed using a first color (red shades), and third flow  210  through the first vessel  204  and fourth flow  212  through the second vessel  208  away from the transducer is displayed using a second different color (blue shades). Intensity is proportional to the velocity of the flow. 
         [0006]    Unfortunately, with color flow mapping, the two colors only show relative flow with respect to the ultrasound transducer. Furthermore, with color flow mapping, blood flow perpendicular to the ultrasound beam cannot be seem Moreover, with color flow mapping, the colors do not indicate the direction and magnitude of the blood flow. In view of at least the above, there is an unresolved need for other approaches for visualizing blood flow. 
       SUMMARY 
       [0007]    Aspects of the application address the above matters, and others. 
         [0008]    In one aspect, an ultrasound imaging console includes receive circuitry that receives a set of echoes produced in response to an ultrasound signal traversing blood flowing in a portion of a vessel in a field of view, a beamformer that beamforms the echoes, a velocity processor that determines flow direction and magnitude of the flowing blood based on the beamformed echoes, and a rendering engine that displays the determined flow direction and magnitude. 
         [0009]    In another aspect, a method includes receiving a set of echoes produced in response to an ultrasound signal traversing blood flowing in a portion of a vessel in a field of view, beamforming the echoes, estimating flow direction and magnitude of blood the flowing blood based on the beamformed echoes, and displaying the determined flow direction and magnitude. 
         [0010]    A computer readable storage medium is encoded with computer readable instructions, which, when executed by a processer, cause the processor to: receive a set of echoes produced in response to an ultrasound signal traversing blood flowing in a portion of a vessel in a field of view, beamform the echoes, estimate flow direction and magnitude of blood the flowing blood based on the beamformed echoes, generate an image based on the beamformed echoes, and displaying indicia representing flow direction and magnitude superimposed over the image, wherein flow direction is displayed using at least one of color or hue and magnitude is displayed using intensity. 
         [0011]    Those skilled in the art will recognize still other aspects of the present application upon reading and understanding the attached description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The application is illustrated by way of example and not limited by the figures of the accompanying drawings, in which like references indicate similar elements and in which: 
           [0013]      FIG. 1  illustrates a prior art approach to estimating blood flow velocity along the axial and transverse direction of a vessel; 
           [0014]      FIG. 2  illustrates a prior art color flow mapping approach for visualizing flow direction relative to the position on the ultrasound transducer; 
           [0015]      FIG. 3  illustrates an example ultrasound scanner configured to visually present blood flow absolute direction and magnitude; 
           [0016]      FIG. 4  illustrates an example visualization of blood flow absolute direction and magnitude along the axial direction; 
           [0017]      FIG. 5  illustrates an example 2D blood flow direction-magnitude map; 
           [0018]      FIG. 6  illustrates example visualization of blood flow absolute direction and magnitude; and 
           [0019]      FIG. 7  illustrates a method. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Initially referring to  FIG. 3 , an example ultrasound imaging console  300  is illustrated. 
         [0021]    A transducer array  302  includes a one dimensional (1D) array of transducer elements, which are configured to transmit ultrasound signals and receive echo signals. Examples of suitable 1D arrays include  128 ,  192 , and/or other dimension arrays, including square and/or rectangular arrays. The array can be linear, curved, and/or otherwise shaped. The array can be fully populated or sparse and/or a combination hereof. 
         [0022]    Transmit circuitry  304  generates a set of pulses that are conveyed to the transducer array  302 . The set of pulses actuates a corresponding set of the transducer elements of the transducer array  302 , causing the elements to transmit ultrasound signals into an examination or scan field of view. In the illustrated embodiment, transmit circuitry  304  generates a set of pulses which produce a transmit signal suitable at least for velocity imaging. 
         [0023]    Receive circuitry  306  receives echoes generated in response to the transmitted ultrasound signals from the transducer  302 . The echoes, generally, are a result of the interaction between the emitted ultrasound signals and the structure (e.g., flowing blood cells, organ cells, etc.) in the scan field of view. 
         [0024]    A controller  308  controls one or more of the transmit circuitry  304  or receive circuitry  306 . Such control can be based on available modes of operation (e.g., velocity flow, A-mode, B-mode, etc.) of the system  300 . In addition, such control can be based on one or more signals indicative of input from a user. 
         [0025]    A user interface (UI)  310  produces the one or more signals indicative of the input from a user. The UI  310  may include one or more input devices (e.g., a button, a knob, a slider, a touch pad, etc.) and/or one or more output devices (e.g., a display screen, lights, a speaker, etc.). 
         [0026]    One or more beamformers  312  process the echoes, for example, by applying time delays, weighting on the channels, summing, and/or otherwise beamforming received echoes. 
         [0027]    A velocity processor  314  processes the beamformed data. In one instance, this includes processing the beamformed data using a transverse oscillation (TO) approach and determining from the processed data one or more velocity components such as a depth (VZ) velocity component and a transverse (VX) velocity component, including direction and magnitude of flow. The TO approach is described in greater detail in U.S. Pat. No. 6,148,224 to Jenson, titled “Apparatus and Method for Determining Movement and Velocities of Moving Objects, filed on Dec. 30, 1998, and assigned to B-K Medical A/S, which is incorporated herein by reference in its entirety. 
         [0028]    An image processor  316  also receives the beamformed data. For B-mode, the image processor  316  processes the data and generates a sequence of focused, coherent echo samples along focused scanlines of a scanplane. The image processor  316  may also be configured to process the scanlines to lower speckle and/or improve specular reflector delineation via spatial compounding and/or perform other processing such as FIR filtering, IIR filtering, etc. 
         [0029]    A scan converter  318  scan converts the output of the image processor  316  to generate data for display, for example, by converting the data to the coordinate system of the display. The scan converter  318  can be configured to employ analog and/or digital scan converting techniques. 
         [0030]    A rendering engine  320  visually presents one or more images with blood flow information via a graphical user interface (GUI) in a display monitor  322 . With respect to flow imaging, the image may include a 2D angular independent flow image showing both flow direction and magnitude, where direction is shown in absolute direction, as opposed to conventional Doppler imaging, where flow is shown towards and away from the ultrasound probe. 
         [0031]    In one instance, hue is used for direction and intensity is used for magnitude based on direction indicia  324  and magnitude indicia  326 . Additionally or alternatively, graphics, such as vectors, flowlines, particles, animation, and/or other indicia, from the magnitude indicia  326  is used for direction. It is to be appreciated that acquiring angular independent flow information simplifies user manipulation of probe as sonographers do not have to search for the best scan angle. This also allows for a reduction in examination time. 
         [0032]    Less training is required to interpret the images since the flow information in both direction and magnitude is visualized. Furthermore, the displayed image can show complex flow such as turbulence or flow vortex in a vessel, such as the carotid artery, the jugular vein, and/or other blood vessel. Moreover, the peak measured transverse velocity component can be two times larger than the peak measured axial component for the same depth. This opens doors to areas where there is a desire to measure fast blood flow parallel to the transducer surface, such as the flow in the fistulas of hemodialysis patients. 
         [0033]    It is to be appreciated that the components  312 ,  314  and/or  316  can be implemented via one or more processors executing one or more computer readable instructions encoded or embedded on computer readable storage medium such as physical memory. Additionally or alternatively, the one or more processors can execute at least one instruction(s) carried by a carrier wave, a signal, or other non-computer readable storage medium such as a transitory medium. 
         [0034]      FIGS. 4 and 5  illustrate an example in which flow direction is shown using graphical indicia (i.e., vectors) and flow direction and magnitude is shown using a two-dimensional color-intensity mapping. 
         [0035]    In  FIG. 4 , vessel portions  402  and  404  along long axes of the vessels are shown. 
         [0036]    Vectors  406  in the vessel  402  show flow direction going right to left, generally horizontally or slightly downward at the far right to acutely upward at the far left. Vectors  408  in the vessel  404  show flow going left to right, acutely downward most of the length of the portion  404 . 
         [0037]    The portion  402  is highlighted using darker colors  403 , which is used to show flow direction from left to right. The portion  404  is highlighted using lighter colors  405 , which is used to show flow direction from right to left. Intensity (or brightness) is used to show velocity magnitude, with a higher intensity representing a larger magnitude. 
         [0038]    With respect to the portion  402 , a region about  410  is higher intensity relative to regions about  412  and  414 , and a region  416  has an intensity between the intensity at  410  and  412 . With respect to the portion  404 , regions about  418  and  420  have higher intensity relative to regions about  422 ,  424 ,  426  and  428 , which have slightly different intensity. 
         [0039]    The vector flow indicia  406  and  408 , the darker colors  403  and the lighter  405  colors (represented via different patterns), and the intensities  410  and  412  and the intensities  420  and  422  are further shown in magnified views  430  and  432 . 
         [0040]      FIG. 5  shows an example velocity direction-magnitude map  500 . An x-axis  502  represent a first color scheme representing transverse velocity direction, with zero transverse velocity at  504 , and a y-axis  506  represent a second color scheme representing axial velocity direction, with zero axial velocity at  508 . 
         [0041]    Regions  510 ,  512 ,  514 ,  516 ,  518 ,  520 ,  522  to  524  show several example colors of the map  500 . The intensity increases from a center region  526  to the periphery of the map  500 . 
         [0042]      FIG. 6  shows the vessel portions  402  and  404  of  FIG. 4  in the transverse plane. Likewise, vectors and colors are used to show flow direction and intensity is used to show magnitude. In this embodiment, the color map  500  is concurrently shown. 
         [0043]    In  FIGS. 4 and 6 , quantitative information can be variously obtained. In one instance, hovering a mouse pointer over and/or clicking on a region of the portion  402  and  404  invokes the rendering engine  320  to display a numerical value representing the flow. 
         [0044]    In another instance, a curve showing velocity as a function of time is visually presented, which shows how velocity evolves in real-time. 
         [0045]    In yet another instance, a velocity profile curve showing velocity as a function of points taken along a line and as a function of time is displayed. Such a curve may useful for vessel surgery and/or other applications. 
         [0046]      FIG. 7  illustrates an example method. 
         [0047]    It is to be understood that the following acts are provided for explanatory purposes and are not limiting. As such, one or more of the acts may be omitted, one or more acts may be added, one or more acts may occur in a different order (including simultaneously with another act), etc. 
         [0048]    At  702 , an ultrasound signal is transmitted into a field of view. 
         [0049]    At  704 , echoes, in response to the ultrasound signal, are received by a transducer array. 
         [0050]    At  706 , the echoes are beamformed. 
         [0051]    At  708 , flow direction and magnitude are determined 
         [0052]    At  710 , the flow direction and magnitude visually presented, for example, with hue and/or graphics showing direction and intensity showing magnitude, superimposed over a B-mode or other image. 
         [0053]    The methods described herein may be implemented via one or more processors executing one or more computer readable instructions encoded or embodied on computer readable storage medium such as physical memory which causes the one or more processors to carry out the various acts and/or other functions and/or acts. Additionally or alternatively, the one or more processors can execute instructions carried by transitory medium such as a signal or carrier wave. 
         [0054]    The application has been described with reference to various embodiments. Modifications and alterations will occur to others upon reading the application. It is intended that the invention be construed as including all such modifications and alterations, including insofar as they come within the scope of the appended claims and the equivalents thereof.