The present invention relates to diagnostic ultrasound methods and systems. In particular, the present invention relates to methods and apparatus for defining a protocol in accordance with which ultrasound scans are automatically performed.
Numerous ultrasound methods and systems exist for use in medical diagnostics. Various features have been proposed to facilitate patient examination and diagnosis based on ultrasound images of the patient. For example, in stress-echo type heart studies, portions of the heart may be scanned before and after a stress test to provide corresponding base-line and stress-level images of the selected portions of the heart.
However, scanning the same portions of the heart during the base-line and stress levels of the tests is difficult using current technology. The operator may have difficulty in capturing the same portion of the heart repeatedly during the stress test because, for example, the patient is breathing harder at each stress level and because the heart is beating faster and moving to a greater extent within the patient's body than during the base-line acquisition. The operator may have difficulty positioning the probe to obtain the same reference views and angles of the scanned object at advanced stress levels as before stress for base-line recording. The base-line and stress-level image slices may not show the same portions and/or views of the heart such that a physician may have to mentally visualize the anatomy based on the differing 2D scans and correct for the differences between the before and after slices.
Further, the user normally obtains multiple ultrasound images while the patient is in a base-line state and an equal number of ultrasound images at each stress level. At base-line and at each stress level, the ultrasound images are recorded continuously to form a cine loop of real-time images of the myocardium along a select scan plane. Also at each base-line and stress level, cine loops of ultrasound images are acquired along multiple scan planes.
Heretofore, the user manually adjusted a series of scan parameters between acquisition along each scan plane. The manual adjustment process was repeated for each scan plane at base-line and at each stress level. This process was slow and awkward for users and delayed completion of a stress test.
A need exists for methods and systems that are able to define a protocol for automated acquisition of ultrasound images along multiple scan planes.
A protocol-based ultrasound method is provided. The ultrasound method provides a template comprised of cells. Each of the cells contain scan parameters defining a scan sequence for acquisition of ultrasound images along scan planes through an object. Prior to scanning the object, parameter values for the scan parameters associated with cells in the template are entered by the user to define the scan sequences along at least two scan planes. The object is scanned with an ultrasound probe to automatically and successively acquire ultrasound images along at least two scan planes based on the parameter values for the scan parameters in the cells.
In accordance with an alternative embodiment, a method displays ultrasound images of an object that is changing states in accordance with a protocol. Each of the ultrasound images is acquired along a corresponding scan plane through the object. A collection of ultrasound images is provided. Each of the ultrasound images is acquired along an associated scan plane while the object is in an associated state. The display is segmented into at least two quadrants or regions. A corresponding ultrasound image is presented in the quadrants, wherein co-displayed ultrasound images correspond to one of a common state of the object and a common scan plane through the object.
In accordance with yet another embodiment, an ultrasound system is provided with memory for storing a template comprised of cells. Each of the cells contains parameters defining acquisition for an ultrasound image along a corresponding scan plane through an object. The configuration includes an input for entering, prior to scanning the object, parameter values for the scan parameters associated with the cells in the template. The system includes a probe for scanning the object to automatically acquire ultrasound images along at least two scan planes based on the parameter values for the scan parameters in the cells.
When excited, the transducer elements 104 produce ultrasonic waveforms that are directed along transmit beams into the subject. The ultrasound waves are back-scattered from density interfaces and/or structures in the body, like blood cells or muscular tissue, to produce echoes which return to the transducer elements 104. The echo information is received and converted into electrical signals by the transducer elements 104. The electrical signals are transmitted by the array transducer 106 to a receiver 108 and subsequently passed to the beamformer 110. In the embodiment described below, the beamformer 110 operates as a transmit and receive beamformer.
The beamformer 110 receives and uses scan parameters 138 to control the operation of the transmitter 102 to generate ultrasound scan beams and the receiver 108 to collect echo information. The beam former through the use of information provided in the scan parameters 138 produces received beam information that may be used in generating ultrasound images. Beamformer 110 delays, apodizes and sums each electrical signal with other electrical signals received from the array transducer 106. The summed signals represent echoes from the ultrasound beams or lines. The summed signals are output from the beamformer 110 to an RF processor 112. The RF processor 112 may generate in phase and quadrature (I and Q) information. Alternatively, real value signals may be generated from the information received from the beamformer 110. The RF processor 112 gathers information (e.g. I/Q information) related to one frame and stores the frame information with time stamp and orientation/rotation information into an image buffer 114. Orientation/rotation information may indicate the angular rotation one frame makes with another. For example, in a tri-plane situation whereby ultrasound information is acquired simultaneously for three differently oriented planes or views, one frame may be associated with an angle of 0 degrees, another with an angle of 60 degrees, and a third with an angle of 120 degrees. Thus, frames may be added to the image buffer 114 in a repeating order of 0 degrees, 60 degrees, 120 degrees, . . . 0 degrees, 60 degrees, 120 degrees, . . . . The first and fourth frame in the image buffer 114 have a first common planar orientation. The second and fifth frames have a second common planar orientation and the third and sixth frames have a third common planar orientation.
Alternatively, in a biplane situation, the RF processor 112 may collect frame information and store the information in a repeating frame orientation order of 0 degrees, 90 degrees, 0 degrees, 90 degrees, etc. The frames of information stored in the image buffer 114 are processed by the 2D display processor 116.
The 2D display processors 116, 118, and 120 operate alternatively and successfully in round-robin fashion processing image frames from the image buffer 114. For example, the display processors 116, 118, and 120 may have access to all of the data slices in the image buffer 114, but are configured to operate upon data slices having one angular orientation. For example, the display processor 116 may only process image frames from the image buffer 114 associated with an angular rotation of 0 degrees. Likewise, the display processor 118 may only process 60 degree oriented frames and the display processor 120 may only process 120 degree oriented frames.
The 2D display processor 116 may process a set of frames having a common orientation from the image buffer 114 to produce a 2D image or view of the scanned object in a quadrant 126 of a computer display 124. The sequence of image frames played in the quadrant 126 may form a cine loop. Likewise, the display processor 118 may process a set of frames from the image buffer 114 having a common orientation to produce a second different 2D view of the scanned object in a quadrant 130. The display processor 120 may process a set of frames having a common orientation from the image buffer 114 to produce a third different 2D view of the scanned object in a quadrant 128.
For example, the frames processed by the display processor 116 may produce an apical 4-chamber view of the heart to be shown in the quadrant 126. Frames processed by the display processor 118 may produce an apical 2-chamber view of the heart to be shown in the quadrant 130. The display processor 120 may produce frames to form an apical long-axis (APLAX) view of the heart to be shown in the quadrant 128. All three views of the human heart may be shown simultaneously in real time in the three quadrants 126, 128, and 130 of the computer display 124.
A 2D display processor, for example the processor 116, may perform filtering of the frame information received from the image buffer 114, as well as processing of the frame information, to produce a processed image frame. Some forms of processed image frames may be B-mode data (e.g. echo signal intensity or amplitude) or Doppler data. Examples of Doppler data include color Doppler velocity data (CDV), color Doppler energy data (CDE), or Doppler Tissue data (DTI)). The display processor 116 may then perform scan conversion to map data from a polar to Cartesian coordinate system for display on a computer display 124.
Optionally, a 3D display processor 122 may be provided to process the outputs from the other 2D display processors 116, 118, and 120. Processor 122 may combine the 3 views produced from 2D display processors 116, 118, and 120 to form a tri-plane view in a quadrant 132 of the computer display 124. The tri-plane view may show a 3D image, e.g. a 3D image of the human heart, aligned with respect to the 3 intersecting planes of the tri-plane. In one embodiment, the 3 planes of the tri-plane intersect at a common axis of rotation. In other embodiments, any number of planes may have any orientation. For example, the user may want to acquire a number of short-axis scan planes simultaneously from the parasternal window at different levels from apex to mitral plane in the heart. In this case, N number of planes are acquired with same rotation angle but different tilt angle.
A user interface 134 is provided which allows the user to input scan parameters 138. The scan parameters 138 are associated with the cells of a template 140 stored in a memory 136. The scan parameters 138 may allow the user to designate whether a biplane or tri-plane scan is desired, and rotation and tilt angles between planes. The scan parameters 138 may allow for adjusting the depth and width of a scan of the object for each of the planes of the biplane or tri-plane. The scan parameters 138 may include parameters for gain, frequency, focus position, mode, contact, and zoom. When performing simultaneous acquisition of scan data from three planes of a tri-plane, the beamformer 110 in conjunction with the transmitter 102 signals the array transducer 106 to produce ultrasound beams that are focused within and adjacent to the three planes that slice the scan object. The reflected ultrasound echoes are gathered simultaneously to produce image frames that are stored in the image buffer 114. As the image buffer 114 is being filled by the RF processor 112, the image buffer 114 is being emptied by the 2D display processors 116, 118, and 120. The 2D display processors 116, 118, and 120 form the data for viewing as 3 views of the scan object in corresponding computer display quadrants 126, 130, and 128. The display of the 3 views in quadrants 126, 130, and 128, as well as an optional displaying of the combination of the 3 views in quadrant 132, is in real time. Real time display makes use of the scan data as soon as the data is available for display.
The probe 202 is moved, such as along a linear or arcuate path, while scanning a region of interest (ROI). At each linear or arcuate position, the probe 202 obtains scan planes 210. Alternatively, a matrix array transducer probe 202 with electronic beam steering may be used to obtain the scan planes 210 without moving the probe 202. The scan planes 210 are collected for a thickness, such as from a group or set of adjacent scan planes 210. The scan planes 210 are stored in the memory 212, and then passed to a volume scan converter 214. In some embodiments, the probe 202 may obtain lines instead of the scan planes 210, and the memory 212 may store lines obtained by the probe 202 rather than the scan planes 210. The volume scan converter 214 may process lines obtained by the probe 202 rather than the scan planes 210. The volume scan converter 214 receives a slice thickness setting from a control input 216, which identifies the thickness of a slice to be created from the scan planes 210. The volume scan converter 214 creates a 2D frame from multiple adjacent scan planes 210. The frame is stored in slice memory 218 and is accessed by a volume rendering processor 220. The volume rendering processor 220 performs volume rendering upon the frame at a point in time by performing an interpolation of the values of adjacent frames. The output of the volume rendering processor 220 is passed to the video processor 222 and the display 224.
The position of each echo signal sample (voxel) is defined in terms of geometrical accuracy (i.e., the distance from one voxel to the next) and ultrasonic response (and derived values from the ultrasonic response). Suitable ultrasonic responses include gray scale values, color flow values, and angio or power Doppler information. Power Doppler information is not suitable for surface rendering of quantitative information. Surface rendering of quantitative information requires the aquisition of a B mode (or gray scale) slice. Interpolation of adjacent frames or planes at different depths is performed in first and second scan planes that intersect with one another along a common axis to derive synthetic ultrasound data estimating a surface of the object.
Prior to scanning the object, parameter values may be entered by the user at 304 for the scan parameters associated with cells in the template defining the protocol. Generic scan parameters may be set before the patient arrives for the exam, such as based on the type of stress exams to be performed. The scan parameters may include patient-specific scan parameters in addition to generic scan parameters, which are set when the patient arrives for the examination. For example, if the dimensions of a patient's heart are larger or smaller than normal, the patient-specific scan parameters may need to be adjusted accordingly.
The parameter values for all of the cells in the template are entered by a user before beginning any portion of the complete examination. For example, the second and third cells may specify scan parameters for the plane angles, tilt and the like that are set to default levels or by the user based on the type of multiplane scan that may be specified in the first cell.
The scan parameters include protocol generic parameters. The scan parameters may define three scan planes intersecting along a common axis extending from the probe. The object is scanned substantially simultaneously along the three scan planes based on the parameter values of an associated cell. Alternatively, the scan parameters may define two scan planes intersecting along a common axis extending from the probe. The object is scanned substantially simultaneously along the two scan planes based on the parameter values of an associated cell. In general, the scan parameters may define multiple planes that are scanned along based on the parameter values of an associated cell. Examples of a template format of cells that may be used to define scan protocols are provided in
The user may select and populate cells 502 and 510 of the template 500 to designate acquiring scan data for both biplane and tri-plane recordings. In selecting and entering parameter information for both columns (biplane and tri-plane) of the template 500, the system 100 of
Some scan parameters may be automatically valued with normally preferred default values as the user enters values for the scan parameters. For example, the user may value the cell 804 with a protocol name indicating that a 4-chamber PLAX tri-plane scan test is needed. The system 100 may then value the angle 814 and the tilt 816 of cells 806, 808, and 810 with appropriate default values for a patient with a normal heart size and shape. If after the patient arrives for testing, the patient's heart size and/or shape are not normal, the user may adjust the values for the angle 814 and the tilt 816 parameters accordingly. Such changes to the scan parameter values may be remembered by the system 100 for performing successive stress tests. In an alternative embodiment, selecting the name of a column in the template (e.g. “Par LAX SAX”) will result in default scan parameters for the number of planes and angles (e.g. 2 planes with rotation angle 90 degrees and tilt angle −5 degrees).
Returning to
Ultrasound images of an object that is changing states in accordance with a protocol are collected at 308. Each of the ultrasound images is acquired along a corresponding scan plane through the object. A collection of ultrasound images is stored in memory 114. Each of the ultrasound images is acquired along an associated scan plane while the object is in an associated state.
Returning to
At 312, corresponding ultrasound images are presented in the quadrants, wherein co-displayed ultrasound images correspond to one of a common state of the object and a common scan plane through the object. Three quadrants, containing ultrasound images acquired at three different scan planes while the object is in a common state may be presented. A recorded series of consecutive ultrasound images may be played back in at least two of the quadrants.
In comparing the views in quadrants 402 and 406, the user is able to see the same area of the heart correspondingly before and after stress inducement. Likewise, quadrants 404 and 408 show a same view of the heart before and after stress inducement. The base-line quadrants 402 and 404 may be a cine loop of images acquired during base-line, while the quadrants 406 and 408 may show live images of the patient after undergoing a stress level 1 (SL1). To acquire or collect 308 the images displayed in the quadrants 402-408, a stress template may be used. Although
The quadrant 710 may display a 2D view of the volume at base-line. A corresponding view may be shown in one of the other quadrants, e.g. the quadrant 702, at a stress level, e.g. at stress level 1 (SL1). The quadrants 704 and 706 may show two different 2D views of the volume at SL1. For example, the view presented in quadrant 704 may be viewing the volume for a short-axis heart view at SL1. The view presented in quadrant 706 may be viewing the volume for a 2-chamber heart view at SL1. The view presented in quadrant 702 may be viewing the volume for a 4-chamber heart view at SL1. Quadrant 708 shows a 3D view from SL1 with at least two cut planes 712 and 714 that indicate the views shown in quadrants 702 and 706. The horizontal cut plane 716 indicates to the user at what depth a short-axis view is shown in quadrant 704. The user via the user interface 134 (
Similar to the use of the template 500 for multiplane acquisition stress testing, a template may be provided and populated for the volumetric 3D/4D stress echo scan. After valuing the user required parameters, e.g. patient-specific parameters and selected views to be displayed, generic parameters may be determined automatically, for example, whether ECG stitching is to be used and if so, the number of stitches to be used. Parameters may be automatically populated in the stress-level cells of the template from the base-line cell. The 3D/4D template preserves the same geometric orientation and/or volume geometry used for base-line for acquisition of volumes for stress-level tests. For example, the quadrants 702, 704, and 706 display views at SL1 of a volume acquired with the same geometric orientation and/or volume geometry as used for the volume of the base-line view in quadrant 710. Preserving the base-line volume geometry for use in collecting volumes for stress levels is accomplished by the automatic population of parameters in the template cells for the stress levels. The cut planes 712 and 714 of the reference view in quadrant 708 may be rotated. When rotating the reference view in quadrant 708, the views in quadrants 702, 704, 706, and 710 are correspondingly rotated. Thus, the orientation of the views presented in quadrants 702, 704, 706, and 710 are synchronized to the view orientation presented to the user in the reference view of the quadrant 708.
In an alternative embodiment, a protocol template may have volume (3D/4D), 2D multiplane recordings, and single plane recordings combined. The template may be populated for a patient (generic parameters valued) before the patient's arrival for stress tests that include volume, multiplane and single plane stress tests.
Exemplary embodiments of diagnostic ultrasound systems are described above in detail. The systems are not limited to the specific embodiments described herein, but rather, components of each system may be utilized independently and separately from other components described herein. Each system component can also be used in combination with other system components.
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.
This application claims priority to and the benefit of the filing date of U.S. Provisional Application No. 60/581,675 filed on Jun. 22, 2004 and which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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60581675 | Jun 2004 | US | |
60583578 | Jun 2004 | US |