Vector flow ultrasound imaging

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.

TECHNICAL FIELD

The following generally relates to ultrasound imaging and more particularly to vector flow ultrasound imaging.

BACKGROUND

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.

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 inFIG. 1in which a transducer array100produces an ultrasound beam102that 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)106can be estimated.

The transverse oscillation (TO) blood velocity estimation approach has been used to estimate both VZ106and the transverse velocity component (VX)108, along the transverse axis110, of the velocity vector112. 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.

Color flow mapping (CFM) is one approach to visually show velocity. An example of this is shown inFIG. 2, in which first flow202through a first vessel204and second flow206through a second vessel208towards the transducer is displayed using a first color (red shades), and third flow210through the first vessel204and fourth flow212through the second vessel208away from the transducer is displayed using a second different color (blue shades). Intensity is proportional to the velocity of the flow.

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 seen. 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

Aspects of the application address the above matters, and others.

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.

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.

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.

Those skilled in the art will recognize still other aspects of the present application upon reading and understanding the attached description.

DETAILED DESCRIPTION

A transducer array302includes a one dimensional (1D) array of transducer elements, which are configured to transmit ultrasound signals and receive echo signals. Examples of suitable 1D arrays include128,192, 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.

Transmit circuitry304generates a set of pulses that are conveyed to the transducer array302. The set of pulses actuates a corresponding set of the transducer elements of the transducer array302, causing the elements to transmit ultrasound signals into an examination or scan field of view. In the illustrated embodiment, transmit circuitry304generates a set of pulses which produce a transmit signal suitable at least for velocity imaging.

Receive circuitry306receives echoes generated in response to the transmitted ultrasound signals from the transducer302. 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.

A controller308controls one or more of the transmit circuitry304or receive circuitry306. Such control can be based on available modes of operation (e.g., velocity flow, A-mode, B-mode, etc.) of the system300. In addition, such control can be based on one or more signals indicative of input from a user.

A user interface (UI)310produces the one or more signals indicative of the input from a user. The UI310may 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.).

One or more beamformers312process the echoes, for example, by applying time delays, weighting on the channels, summing, and/or otherwise beamforming received echoes.

A velocity processor314processes 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.

An image processor316also receives the beamformed data. For B-mode, the image processor316processes the data and generates a sequence of focused, coherent echo samples along focused scanlines of a scanplane. The image processor316may 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.

A scan converter318scan converts the output of the image processor316to generate data for display, for example, by converting the data to the coordinate system of the display. The scan converter318can be configured to employ analog and/or digital scan converting techniques.

A rendering engine320visually presents one or more images with blood flow information via a graphical user interface (GUI) in a display monitor322. 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.

In one instance, hue is used for direction and intensity is used for magnitude based on direction indicia324and magnitude indicia326. Additionally or alternatively, graphics, such as vectors, flowlines, particles, animation, and/or other indicia, from the magnitude indicia326is 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.

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.

It is to be appreciated that the components312,314and/or316can 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.

FIGS. 4 and 5illustrate 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.

InFIG. 4, vessel portions402and404along long axes of the vessels are shown.

Vectors406in the vessel402show flow direction going right to left, generally horizontally or slightly downward at the far right to acutely upward at the far left. Vectors408in the vessel404show flow going left to right, acutely downward most of the length of the portion404.

The portion402is highlighted using darker colors403, which is used to show flow direction from left to right. The portion404is highlighted using lighter colors405, 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.

With respect to the portion402, a region about410is higher intensity relative to regions about412and414, and a region416has an intensity between the intensity at410and412. With respect to the portion404, regions about418and420have higher intensity relative to regions about422,424,426and428, which have slightly different intensity.

The vector flow indicia406and408, the darker colors403and the lighter405colors (represented via different patterns), and the intensities410and412and the intensities420and422are further shown in magnified views430and432.

FIG. 5shows an example velocity direction-magnitude map500. An x-axis502represent a first color scheme representing transverse velocity direction, with zero transverse velocity at504, and a y-axis506represent a second color scheme representing axial velocity direction, with zero axial velocity at508.

Regions510,512,514,516,518,520,522to524show several example colors of the map500. The intensity increases from a center region526to the periphery of the map500.

FIG. 6shows the vessel portions402and404ofFIG. 4in 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 map500is concurrently shown.

InFIGS. 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 portion402and404invokes the rendering engine320to display a numerical value representing the flow.

In another instance, a curve showing velocity as a function of time is visually presented, which shows how velocity evolves in real-time.

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.

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.

At702, an ultrasound signal is transmitted into a field of view.

At704, echoes, in response to the ultrasound signal, are received by a transducer array.

At706, the echoes are beamformed.

At708, flow direction and magnitude are determined.

At710, 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.

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.

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.