Abstract:
A method for monitoring a target in a medical display in a medical imaging apparatus includes receiving echo signals from an area of interest of a patient, extracting raw data from the received echo signals, processing the extracted raw data to display a dual mode image on the medical display, and setting a location and displaying a first marker/cursor in a first image of the dual mode image. In addition, the method further includes determining a corresponding location of the marker/cursor in a second image of the dual mode image, and displaying a second marker/cursor in the second image of the dual mode image at the corresponding location simultaneously with the displaying of the first marker/cursor in the first image.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    This invention relates generally to ultrasound systems that image anatomical structures, and more particularly, to a method and apparatus for displaying computer-coordinated markers simultaneously on dual ultrasound images of different modes in “real time.” 
         [0002]    Ultrasound contrast imaging is used for tumor detection and characterization in some parts of the world. Microbubbles are used today as contrast agents. A physician will generally inject the contrast agent into the patient. The contrast agent is used to isolate and identify where in an organ, for example, in a liver, to perform a biopsy. Generally, there will be a biopsy bracket on the ultrasound probe. A display will provide a centerline and two guidelines giving a range within which a biopsy needle will be guided. In addition, a depth marker may also appear on the screen and the lesion may be measured. 
         [0003]    The contrast agents are able to enter blood microcirculation for several minutes without breaking under a low mechanic index acoustic field. Contrast agents increase blood backscattering signal strength and make blood flow from small vessels visible in images in which they would be masked by a surrounding tissue echo. Because of differences in vascularity, enhancement patterns are different between normal tissue and tumors, as well as between different tumor types. The differences in enhancement patterns are used for tumor detection and characterization. 
         [0004]    To obtain improved contrast performance, contrast imaging suppresses the tissue background to increase the contrast to tissue ratio. When a tissue background is perfectly suppressed, a target becomes difficult to see before contrast injection. A dark tissue background causes difficulty in maintaining the small lesion in an image plane due to movement from patient breath, patient motion and probe motion. For diagnosis, it is important to know the exact location of the lesion in the image and to see the contrast enhancement dynamic pattern over a period of time. Thus, a B mode image is often used as reference for monitoring the lesion position and a contrast image is displayed alongside the B mode image in real time in a dual imaging mode. The dual image mode makes it simpler to monitor the target image, but it is sometimes still difficult to know the exact position of the lesion in the contrast mode image when the lesion is small. Moreover, contrast agents do not remain in the body for an extended time. Hence, contrast examinations have a limited viewing time. In the meantime, the user (e.g., the physician) is busy storing images and clips to a hard drive in the ultrasound machine and has to concentrate on what he or she is doing during the relatively limited examination time. 
         [0005]    Ultrasound systems may use recording systems to store a series of images. Video recorders or a digital memory are incorporated into many conventional ultrasound systems. The information stored by and played back from a digital memory is generally limited by the analysis being performed during recording. The reason for this limitation is that a conventional digital memory receives data produced after the echo signals have been processed and prepared for display. Therefore, the digital memory stores only the data resulting from a particular processing operation carried out upon the echo signals at the time the patient was examined. The processing operation is determined by the present mode of operation and parameter settings. Thus, processed data that is stored may ignore and/or eliminate certain information from the echo signals. This ignored or eliminated information cannot be recovered. For example, an abnormality recognized in a recorded image after the patient has left cannot be analyzed in greater detail unless the patient returns for a new scanning session and then only if the abnormality present during the original scanning session is again detected. Accordingly, images that are recorded while inaccurate or less than optimal parameters are set may be useless. Thus, increases in the length or number of ultrasound scanning sessions may result, thereby increasing patient exposure time, patient discomfort and procedure costs. Furthermore, studies employing contrast agents are limited in the number of different analyses that can be performed during the rapid decay of the contrast agent. 
       SUMMARY OF THE INVENTION 
       [0006]    In one embodiment of the present invention, a method is provided for monitoring a target in a medical display in a medical imaging apparatus. The method includes receiving echo signals from an area of interest of a patient, extracting raw data from the received echo signals, processing the extracted raw data to display a dual mode image on the medical display, and setting a location and displaying a first marker/cursor in a first image of the dual mode image. In addition, the method further includes determining a corresponding location of the marker/cursor in a second image of the dual mode image, and displaying a second marker/cursor in the second image of the dual mode image at the corresponding location simultaneously with the displaying of the first marker/cursor in the first image. 
         [0007]    In another embodiment of the present invention a method is provided for analyzing raw data generated by a medical imaging apparatus. The method includes processing stored raw data to generate a displayable dual mode image, determining whether or not to display markers/cursors at a saved location, and displaying the displayable dual mode image with or without the markers/cursors at the saved location, depending upon results of said determining whether or not to display markers/cursors at the saved location. 
         [0008]    In yet another embodiment of the present invention a medical imaging apparatus is provided that includes a probe having transducers configured to transmit and receive a signal to and from a patient, a signal processor configured to process raw data resulting from signals received from the patient into a displayable image, a marker/cursor generator configured to place markers/cursors into the displayable image, and a display configured to display the displayable image. The medical imaging apparatus is configured to receive echo signals from an area of interest of a patient, extract raw data from the received echo signals, and process the extracted raw data to display a dual mode image on the medical display. The medical imaging apparatus is further configured to set a location and displaying a first marker/cursor in a first image of the dual mode image, determine a corresponding location of the marker/cursor in a second image of the dual mode image, and display a second marker/cursor in the second image of the dual mode image at the corresponding location simultaneously with the displaying of the first marker/cursor in the first image. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a block diagram of an ultrasound imaging system constructed in accordance with one embodiment of the present invention. 
           [0010]      FIG. 2  illustrates a flow chart of a procedure for accumulating and storing ultrasound information in accordance with one embodiment of the present invention. 
           [0011]      FIG. 3  illustrates a flow chart of a procedure for displaying and analyzing off-line ultrasound information in accordance with one embodiment of the present invention. 
           [0012]      FIG. 4  illustrates an image displayed in dual contrast imaging mode by the apparatus of  FIG. 1 , wherein the left image is a B mode image and the right image is a contrast image. 
           [0013]      FIG. 5  illustrates an image generated by processing raw data stored by the apparatus of  FIG. 1  and showing a complete image without the arrows shown in  FIG. 4 . 
           [0014]      FIG. 6  illustrates an image generated by processing raw data stored by the apparatus of  FIG. 1  and showing an image with an arrow displayed in corresponding locations in the B mode image and the contrast image, but moved relative to the position of the arrow in  FIG. 4 . 
           [0015]      FIG. 7  illustrates a portable ultrasound system formed in accordance with an embodiment of the present invention. 
           [0016]      FIG. 8  illustrates an example of a pocket-sized ultrasound system formed in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0017]    The foregoing summary, as well as the following detailed description of certain embodiments of the present invention will be better understood when read in conjunction with the appended drawings. To the extent that the figures illustrate diagrams of the functional blocks of various embodiments, the functional blocks are not necessarily indicative of the division between hardware circuitry. Thus, for example, one or more of the functional blocks (e.g., processors or memories) may be implemented in a single piece of hardware (e.g., a general purpose signal processor or a block of random access memory, hard disk, or the like). Similarly, the programs may be stand alone programs, may be incorporated as subroutines in an operating system, may be functions in an installed software package, and the like. It should be understood that the various embodiments are not limited to the arrangements and instrumentality shown in the drawings. 
         [0018]    As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property. 
         [0019]    Contrast images obtained via ultrasound have a weak tissue background. To provide a more positive identification of significant features such as, for example, tumors, some embodiments of the present invention provide a dual contrast imaging display having a B mode image side-by-side with a contrast image. The B mode image serves as a reference, for example, to help the user find the target position (e.g., the tumor position) in the contrast image. Various configurations of the present invention provide a dual marker/cursor display to synchronize the indicated target positions in the contrast image and the B mode image when an ultrasound imaging apparatus is in dual image mode. 
         [0020]    When a lesion appears on the B mode image, a user is able to position a marker/cursor (e.g., an arrow) on the B mode image to indicate the lesion position. At the same time, the ultrasound imaging apparatus positions a marker/cursor (e.g., another arrow) at a corresponding position on the contrast image. With the help of the marker/cursor on the contrast image, a user can focus his or her attention on the contrast enhancement dynamic change of the lesion. In some embodiments of the present invention, the user is also able to activate/deactivate the dual marker/cursor display by a key or a button. The user can also select to always display the marker/cursor by default on both the B mode image and the contrast mode image. 
         [0021]    In some embodiments of the present invention, medical image data is stored in raw form. The marker/cursor is not stored in a manner that interferes with storing an entire image. However, the marker/cursor can be stored in a separate file or a separate section of the raw image data so as to retain integrity of the raw data. (Hereinafter, either storage method shall be referred to as having the marker/cursor stored “separately from the raw data.”) The stored raw data can thus be processed and viewed later with or without the marker or cursor, thereby allowing a user to view anything that might have been hidden underneath the cursor. In embodiments in which the marker/cursor is separately stored, the marker/cursor can be restored during this later processing and viewing using supplied software, firmware, and/or special purpose hardware (hereinafter referred to as “software” or “special purpose hardware” for economy of description). Also, in some embodiments, data can be transferred from the imaging apparatus to a workstation where the marker/cursor can be displayed if desired. 
         [0022]    By separating markers/cursors that are placed on a displayed image in real time during a procedure from stored raw data, a user who finds the marker in a inconvenient location (e.g., obscuring an object of interest) can move or remove the marker, or make measurements after the examination of the patient in the case where measurements were not made during the examination. 
         [0023]    A block diagram of one embodiment of an ultrasound system (generally indicated at  10 ) is shown in  FIG. 1 . Ultrasound system  10  includes a transmitter  12  that drives transducers  14  within a probe  16  to emit pulsed ultrasonic signals into a body. The ultrasonic signals emitted by transducers  14  are backscattered from structures in the body, like blood cells, muscular tissue, organ tissue, and/or tumors to produce echoes which return to the transducers  14 . The echoes are detected by a receiver  18 . The received echoes are passed through a beamformer  19  that performs beam forming and outputs an RF signal. The RF signal emitted by beamformer  19  passes through an RF processor  20 . In one embodiment of the present invention, the RF signal data (raw data) may then be routed directly to a raw data memory  22  for storage. In another embodiment, RF processor  20  may include a complex demodulator (not shown) that demodulates the RF signal to form I, Q data pairs (also considered raw data) representative of the echo signals prior to storage in raw data memory  22 . In some embodiments, RF processor  20  may provide both raw RF signal data or raw  1 , Q data pairs, or a choice of either source of raw data to store in raw data memory  22 . 
         [0024]    Ultrasound system  10  also includes a signal processor  24  to process the received echo signal data (i.e., RF signal data or I, Q data pairs) and prepare an image for display on display  30 . Signal processor  24  may receive raw data either directly from RF processor  20  or from raw data memory  22  in one embodiment of the present invention. Signal processor  24  is adapted, either through software or special purpose hardware, to perform one or more processing operations from a plurality of selectable processing operations on the received echo signal data. Echo signal data may be processed and displayed in real-time during a scanning session as the echo signals are received. Additionally or alternatively, the echo signal data may be stored in raw data memory  22  during a scanning session and then, in a post-storage (off-line) operation, retrieved from raw data memory  22 , processed by signal processor  24  and displayed on display  30 . 
         [0025]    Also in one embodiment of the present invention, raw data memory  22  is of sufficient capacity to store at least several seconds of echo signal data for multiple range positions along multiple scan lines. Raw data memory  22  may comprise any known data storage medium, such as magnetic storage, flash memory, RAM, and/or optical memory. Raw data memory  22  may also allow the archiving of raw data from multiple scanning sessions and/or multiple patients. 
         [0026]    Signal processor  24  may employ any known signal processing and data manipulation techniques to provide any known ultrasound mode or analysis that has conventionally been carried out in real-time during a scanning session. In one embodiment of the present invention, signal processor  24  is configured to display a dual-mode, side-by-side image comprising a B mode image and a contrast image. Also in one embodiment, these signal processing and data manipulation techniques may be carried out in a post-storage (off-line) operation on stored raw data. Furthermore the various known parameters of signal processing and data manipulation may be selectably modified during off-line playback to optimize the displayed output. 
         [0027]      FIG. 2  illustrates a flow chart  100  of a procedure for accumulating and storing ultrasound information in one embodiment of the present invention, and that is suitable for use with ultrasound imaging apparatus  10  of  FIG. 1 . Starting at  102 , a physician (or other individual permitted to do so) injects a contrast agent into blood circulation at or near an area of interest of a patient, such as a liver. At  104 , transmitter  12 , transducers  14 , probe  16 , receiver  18 , and beam former  19  are operated to transmit and receive ultrasound echo signals (raw RF data) from an area of interest (e.g., the liver) of the patient. At  106 , RF processor  20  extracts raw data, for example, in the form of raw RF data or I and Q data pairs. 
         [0028]    Some embodiments allow the user to make a choice as to whether the raw data is stored in memory  22 , as shown at  108 . If the choice is to store raw data, or if an embodiment is used that always stores raw data, the raw data is stored in raw data memory  22  at  110 , and the raw data is processed next (or simultaneously) at  112 . Otherwise, the process continues at  112  by processing the raw data. For economy of explanation, it will be assumed hereafter that raw data is stored at  110 . It will be understood that the sequence represented by  108  and  110  may occur at one or more other places in the procedure represented by flow chart  100 , either as an alternative or in addition to the location in the procedure shown in flow chart  100 . For example, it may be desirable in some embodiments to make a decision after step  114  (after the image is viewed) regarding whether the raw data is stored. As another example, the decision to save raw data could be made in some embodiments either before or after the decision is made to save the marker cursor location at  122 . 
         [0029]    Next, at  114 , side-by-side images of the area of interest operated by signal processor  24  are displayed on display  30 . In embodiments represented in  FIG. 1 , for example, these images can be generated either by signal processor  24 , as indicated by a dashed connector, and/or by marker/cursor generator  28 , without displaying a marker/cursor. Marker/cursor generator  24  may, in some embodiments, be part of signal processor  24 . For purposes of economy of explanation, it will henceforth be assumed that the side-by-side images comprise a B mode image and a contrast image. 
         [0030]    Next, at  116 , if the dual marker/cursor display mode is not activated by the user by manipulating user interface  26 , the procedure ends at  126 . It should be understood that, rather than ending, the procedure may enter a loop or an interrupt routine, or an equivalent, to continue to display and update the display and/or allow the dual marker/cursor display mode to be activated at a later time during the current medical procedure. For example, in some embodiments of procedure  100 , if the dual marker/cursor display mode is not activated at  116 , the procedure may loop back to  104  to update the display. Locations can be correlated between two images because the same raw data is used to produce both of the images. Thus, pixels in 2-D images that correspond to the same physical location can be readily located. Moreover, each image has the same number of horizontal pixels and the same number of vertical pixels. Thus, because the images represent the same projection of the same physical plane, it is enough in some embodiments to indicate the same pixel pair location in both images. 
         [0031]    If the dual marker/display mode is activated at  116 , then at  118 , the marker/cursor is set and displayed in the B mode image, and at  120 , a corresponding location of the marker/cursor is determined and the marker/cursor is simultaneously displayed at the determined location in the contrast image. More generally, either image in the dual display mode could be used as the image on which the marker/cursor is initially set and the other as the image on which the corresponding location is determined. 
         [0032]    Next, at  122 , if the user has selected an option to save the marker/cursor location along with the raw data, the marker/cursor location is saved separately from (or in a separate section) of the raw data file corresponding to the displayed image at  124 . (An image comprises information in the form of vectors representing an angle and an echo time, the latter, in combination with the speed of sound, representing a depth of the image. Each vector lasts for a certain period of time, which is mapped to the depth of the image. Thus, the saved marker/cursor location can be stored as an image ID to identify to which image the saved location relates, an angle, and an echo depth.) Otherwise, the procedure ends at  126  (or loops, as described above). The end at  126  is also reached directly from  122  if the user has not selected to save the marker/cursor location. 
         [0033]      FIG. 3  illustrates a flow chart  200  of a procedure for displaying and analyzing off-line ultrasound information in one embodiment of the present invention. An off-line signal analysis is initiated at  202 , either on apparatus  10  or on a computer or workstation or other suitable computer platform. To use a computer or workstation, it is presumed that stored raw data in memory  22  has either been downloaded into the memory of the computer or workstation or made available via a wired or wireless network or direct connection. Next, a stored data set is selected from the stored raw data at  204  and an analysis and display mode is selected at  206 . For economy of explanation, it will be assumed that a dual mode of B mode and contrast mode is selected, so at  208 , the stored data set is processed and displayed on a dual mode display. 
         [0034]    Next, at  210 , if there is a stored marker/cursor location associated with the raw data set, the marker/cursor is displayed in corresponding locations on both portions of the dual mode image at  214 . Otherwise, the operation at  214  is skipped. Some embodiments of the present invention also allow a user to toggle the display of the marker/cursor, which allows the user to see undisturbed any features obscured by the marker/cursor. Thus, at  212 , if the marker/cursor display has been toggled by the user, the display of the marker/cursor is toggled on or off at  218  as appropriate. In some embodiments, the user is able to specify whether the marker/cursor display is on or off, rather than toggled. In either case, at  216 , the next check is to determine whether the marker/cursor display is on. If not, the procedure loops back to  212  to wait for the marker/cursor to be toggled on. Otherwise, a check is performed to determine whether, in the current display, the marker/cursor has been manually moved by the user. If not, the procedure loops back to  212 . Otherwise, the marker/cursors displayed in both portions of the dual mode display are moved to the correct positions that each correspond to the movement specified by the user before the procedure loops back to  212 . Thus, a user is able to display the dual mode display with or without the marker/cursor placed during a medical procedure, allowing the user to see what might have been obscured by the marker/cursor. The user is also able to display a different marker/cursor on both halves of the dual mode display, to allow measurements to be made and/or allow a different location in the region of interest to be highlighted. 
         [0035]      FIG. 4  illustrates a region of interest displayed on display  30  in dual contrast imaging mode by apparatus  10  of  FIG. 1 , wherein left image  302  is a B mode image and right image  304  is a contrast image. An arrow  310  placed by the user during an examination points to a suspected tumor  306  shown on B mode image  302 .  FIG. 4  could represent a display  30  during an examination or raw image data stored by apparatus  10  and processed after the examination. In the case of the display during an examination, the user may place arrow  310  on B mode image  302  and have apparatus  10  calculate and determine the corresponding location for arrow  312  on contrast image  304 . In the case of raw image data stored by apparatus  10  and processed after examination, the location of arrows  310  and  312  are stored separately from the raw data (i.e., in a separate location from the raw data file or record, or in a separate section of the raw data file or record) and restored to images  302  and  304  after these images are processed from the raw data. Thus, it is possible to display a complete B mode image  302  and a complete contrast image  304  by turning the marker/cursor display off, as shown in  FIG. 5 , to reveal any features  318 ,  320  that may have been obscured by arrows  310  and  312 . It is also possible to change the location of the marker/cursor to have an arrow  310  highlight a different object or structure  314  in image  302  and have apparatus  10  (or a computer or other suitable workstation) compute a location and place arrow  312  at a corresponding location to highlight the same location  316  in contrast image  304  as object or structure  314  in B mode image  302 . 
         [0036]      FIG. 7  illustrates a miniaturized ultrasound system  400  in which various embodiments may be implemented. As used herein, “miniaturized” means that the ultrasound system is a handheld or hand-carried device or is configured to be carried in a person&#39;s hand, briefcase-sized case, or backpack. For example, ultrasound system  400  may be a hand-carried device having a size of a typical laptop computer, for instance, having dimensions of approximately 2.5 inches in depth, approximately 14 inches in width, and approximately 12 inches in height. Ultrasound system  400  may weigh about ten pounds 
         [0037]    An ultrasound probe  402  has a connector end  404  that interfaces with ultrasound system  400  through an I/O port  406  on ultrasound system  400 . Probe  402  has a cable  408  that connects a connector end  404  and a scanning end  410  that is used to scan a patient. Ultrasound system  400  also has a display  412  and a user interface  414 . 
         [0038]      FIG. 8  shows an example of a pocket-sized ultrasound system  460  in which various embodiments may be implemented. By way of example, pocket-sized ultrasound system  460  may be approximately 2 inches wide, approximately 4 inches in length, and approximately 0.5 inches in depth and weigh less than 3 ounces. Pocket-sized ultrasound system  460  generally includes a display  462 , a user interface  464  (e.g., a keyboard, which may include soft keys such as soft key  461 ) and an input/output (I/O) port  466  for connection to probe  402 . It should be noted that the various embodiments may be implemented in connection with a miniaturized ultrasound system having different dimensions, weights, and power consumption. In some embodiments, the pocket-sized ultrasound system  460  may provide the same functionality as ultrasound system  400  of  FIG. 7 . 
         [0039]    A technical effect of at least one embodiment of the present invention is the processing of stored raw data and the display of the processed data after the ultrasound procedure. The later processing and display of the raw data permits images to be displayed with or without a marker or cursor that may have been displayed during the ultrasound procedure, thereby allowing a user to see anything that might have been hidden underneath the marker or cursor. Also, a marker/cursor can be restored in some embodiments during this later processing and displaying by using supplied software, firmware, and/or special purpose hardware (hereinafter referred to as “software or special purpose hardware” for economy of description). Also, in some embodiments, a technical effect is the communication of raw data from the imaging apparatus to a workstation by the imaging apparatus. In these embodiments, the marker/cursor can be displayed or not, as the user chooses. Furthermore, a user who finds the marker in an inconvenient location (e.g., obscuring an object of interest) can move or remove the marker, or make measurements after the examination of the patient in case such measurements were not made during the examination. 
         [0040]    Also, it will be appreciated that, in some embodiments of the present invention, the real time dual mode display of an imaging apparatus can be used by a user to place a marker/cursor on one side of the dual mode display (e.g., the B mode image) to indicate a lesion position. At the same time, the imaging apparatus can place a marker/cursor at the same position on the other side of the dual mode display (e.g., a contrast image). With the help of the marker/cursor on the other side of the dual mode display, it can be much easier for a user to focus his or her attention (e.g., on the contrast enhancement dynamic change of a lesion). 
         [0041]    While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.