`US 20060020204Al
`
`(19) United States
`(12) Patent Application Publication
`Serra et al.
`
`(10) Pub. No.: US 2006/0020204 Al
`Jan. 26, 2006
`( 43) Pub. Date:
`
`(54) SYSTEM AND METHOD FOR
`THREE-DIMENSIONAL SPACE
`MANAGEMENT AND VISUALIZATION OF
`ULTRASOUND DATA ("SONODEX")
`
`(75)
`
`Inventors: Luis Serra, Singapore (SG); Chua
`Beng Choon, Singapore (SG)
`
`Correspondence Address:
`KRAMER LEVIN NAFTALIS & FRANKEL
`LLP
`INTELLECTUAL PROPERTY DEPARTMENT
`1177 AVENUE OF THE AMERICAS
`NEW YORK, NY 10036 (US)
`
`(73) Assignee: Bracco Imaging, S.p.A., Milano (IT)
`
`(21) Appl. No.:
`
`11/172,729
`
`(22) Filed:
`
`Jul. 1, 2005
`
`Related U.S. Application Data
`
`(60) Provisional application No. 60/585,214, filed on Jul.
`1, 2004. Provisional application No. 60/660,858, filed
`on Mar. 11, 2005. Provisional application No. 60/585,
`462, filed on Jul. 1, 2004.
`
`Publication Classification
`
`(51)
`
`Int. Cl.
`A61B 8/00
`(2006.01)
`(52) U.S. Cl. .............................................................. 600/437
`
`ABSTRACT
`(57)
`A system and method for the imaging management of a 3D
`space where various substantially real-time scan images
`have been acquired is presented. In exemplary embodiments
`according to the present invention, a user can visualize
`images of a portion of a body or object obtained from a
`substantially real-time scanner not just as 2D images, but as
`positionally and orientationally located slices within a par(cid:173)
`ticular 3D space. In such exemplary embodiments a user can
`convert such slices into volumes whenever needed, and can
`process the images or volumes using known image process(cid:173)
`ing and/or volume rendering techniques. Alternatively, a
`user can acquire ultrasound images in 3D using the tech(cid:173)
`niques of UltraSonar or 4D Ultrasound. In exemplary
`embodiments according to the present invention, a user can
`manage various substantially real-time images obtained,
`either as slices or volumes, and can control their visualiza(cid:173)
`tion, processing and display, as well as their registration and
`fusion with other images, volumes and virtual objects
`obtained or derived from prior scans of the body or object of
`interest using various modalities.
`
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`Patent Application Publication Jan. 26, 2006 Sheet 9 of 26
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`Integrated Approach
`
`S t~
`display
`(optional)
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`Normal or Stereoscopic
`Monitor
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`graphics card
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`Acquisition System
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`1
`
`SYSTEM AND METHOD FOR
`THREE-DIMENSIONAL SPACE MANAGEMENT
`AND VISUALIZATION OF ULTRASOUND DATA
`("SONODEX")
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`
`[0001] This application claims the benefit of the following
`U.S. Provisional Patent Applications: (i) Ser. No. 60/585,
`214, entitled "SYSTEM AND METHOD FOR SCANNING
`AND IMAGING MANAGEMENT WITHIN A 3D SPACE
`("SonoDEX")", filed on Jul. 1, 2004; (ii) Ser. No. 60/585,
`462, entitled "SYSTEM AND METHOD FOR A VIRTUAL
`INTERFACE FOR ULTRASOUND SCANNERS ("Virtual
`Interface")", filed on Jul. 1, 2004; and (iii) Ser. No. 60/660,
`858, entitled "SONODEX: 3D SPACE MANAGEMENT
`AND VISUALIZATION OF ULTRASOUND DATA", filed
`on Mar. 11, 2005.
`
`[0002] The following related United States patent appli(cid:173)
`cations, under common assignment herewith, are also fully
`incorporated herein by this reference: Ser. No. 10/469,294
`(hereinafter "A Display Apparatus"), filed on Aug. 29, 2003;
`Ser. No. 10/725,773 (hereinafter "Zoom Slider"), Ser. No.
`10/727,344 (hereinafter "Zoom Context"), and Ser. No.
`10/725,772 (hereinafter "3D Matching"), each filed on Dec.
`1, 2003; Ser. No. 10/744,869 (hereinafter "UltraSonar"),
`filed on Dec. 22, 2003, and Ser. No. 60/660,563 entitled "A
`METHOD FOR CREATING 4D IMAGES USING MUL(cid:173)
`TIPLE 2D IMAGES ACQUIRED IN REAL-TIME ("4D
`Ultrasound"), filed on Mar. 9, 2005.
`
`TECHNICAL FIELD
`
`[0003] The present invention relates to substantially real(cid:173)
`time imaging modalities, such as ultrasound or the equiva(cid:173)
`lent, and more precisely relates to the interactive display and
`manipulation of a three-dimensional space for which a
`plurality of scans have been performed.
`
`BACKGROUND OF THE INVENTION
`
`[0004] A substantially real-time image produced by a
`probe, such as, for example, an ultrasound probe, represents
`a cut through an organ or other 3D anatomical structure of
`a given patient. Such an image has a 3D position and
`orientation relative to the patient's depicted organ or other
`anatomical structure, and knowing this 3D position and
`orientation is often key to a proper interpretation of the
`ultrasound image for both diagnostic as well as interven(cid:173)
`tional purposes. As an example of the latter is when, for
`example, a clinician plans an intervention and must decide
`precisely where to insert a needle or therapeutically direct an
`ultrasound beam.
`
`[0005] Moreover, key in interpreting substantially real(cid:173)
`time images is the time at which a particular image was
`acquired relative to the time when the scan started. This is
`especially true in cases where one or more contrast media
`have been injected into the arteries ( or other vessels) of a
`patient, given the fact that a contrast fluid's signal varies
`with time as well as organ intake. The body is not a
`stationary object, but a time-varying one. There is much
`evidence that indicates that it is not enough to simply
`observe an organ (or a pathology) as a stationary object but
`it is necessary to perceive it as part of a time-varying process
`
`in order to truly understand its function. The most obvious
`is the heart, since it moves. One 3D image of gives one view,
`but to understand the ejection fraction, or to analyze the
`condition of a valve it is key to visualize its movement. In
`the case of a tumor, and when using contrast media and
`ultrasound, what happens is that the contrast flows through
`the arteries, then reaches and fills the tumor, and then washes
`out. It is important to visualize the entire process (wash in
`and wash out) to understand how vessels are feeding the
`tumor, as well as how much blood is the tumor taking in, in
`order to understand its aggressiveness. There is no single
`picture that can show this process. One at best can capture
`the image ( or volume) that shows the time point when the
`contrast is filling the tumor at its maximum, but that misses
`the time when the vessels are visible. Thus, the rate of
`contrast intake is important in order to diagnose and under(cid:173)
`stand the pathology.
`
`[0006] Moreover, having a volume (and not just a slice
`with position and orientation) is essential to any quantifica(cid:173)
`tion process. If there is only a probe cutting through an organ
`that is moving (due, for example, to breathing or due to its
`own movement, such as, for example, the heart) the resulting
`image can be hard to compare against another image taken
`a fraction of a second later since the organ in question will
`have moved and thus the cut will be in another, slightly
`shifted, part of the organ. However, if a comparison is made
`from one volume to another volume, such error can be
`minimized since the volume is made of several cuts and it
`averages the positioning problem.
`
`[0007] Notwithstanding the interpretational value of such
`additional information, historically conventional ultrasound
`scanners, for example, simply displayed a 'flat' image of the
`cutting plane into a given organ of interest, and provided no
`reference as to the relative position of the displayed cutting
`plane relative to anatomical context or to the displayed cut's
`acquisition time.
`
`[0008] To remedy this problem, state of the art ultrasound
`scanners, such as, for example, models manufactured by
`Kretz (now a GE company) and Philips, added 3D volu(cid:173)
`metric acquisition capabilities to their ultrasound probes. As
`a result they can display a 4D volume (i.e., a volume that
`changes with time) by producing a series of acquired images
`that can then be reconstructed into a volume. The resulting
`volume can then be displayed (after appropriate resampling)
`using standard volume rendering techniques. Nonetheless,
`while the individual slices comprising such a volume are
`loosely registered to each other (loosely because the sub(cid:173)
`ject's body is moving throughout the acquisition, and thus
`the body does not have a fixed spatial relationship to the
`probe during the acquisition) they are not registered in any
`sense to the 3D patient space.
`
`[0009] Moreover, even if such a volume is acquired and
`displayed, the physical interfaces provided to manipulate
`these volumes are not themselves three-dimensional, gen(cid:173)
`erally being nothing more than a standard computer key(cid:173)
`board and mouse (or the equivalent, such as a trackball).
`Accordingly, using such tools to effect 3D operations neces(cid:173)
`sitates awkward mappings of 3D manipulations onto essen(cid:173)
`tially 2D devices. The necessity of such awkward mappings
`may be one of the reasons why 3D visualization has not
`gained the acceptance in the medical community that it may
`be due.
`
`
`
`US 2006/0020204 Al
`
`Jan.26,2006
`
`2
`
`[0010] Additionally, some systems, such as, for example,
`the Esaote TM virtual navigator, described at www.esaote(cid:173)
`.com, attempt to provide a user with co-registered pre-scan
`data. However, because in such systems the display of
`ultrasound is restricted to the plane of acquisition, the
`pre-scan data is provided as 2D slices that match the plane
`of the ultrasound slice, and the ultrasound and correspond(cid:173)
`ing pre-operative scan cut are simply placed side-by-side for
`comparison, a user does not gain a 3D sense of where the
`ultrasound slice fits in vis-a-vis the patient space as a whole.
`[0011] What is thus needed in the art is a means of
`correlating ultrasound scans with the 3D space and time in
`which they have been acquired. What is further needed is an
`efficient and ergonomic interface that can allow a user to
`easily interact with ultrasound scan data as well as pre(cid:173)
`operative imaging and planning data in three-dimensions.
`
`SUMMARY OF THE INVENTION
`[0012] A system and method for the imaging management
`of a 3D space where various substantially real-time scan
`images have been, or are being, acquired are presented. In
`exemplary embodiments of the present invention, a user can
`visualize images of a portion of a body or object obtained
`from a substantially real-time scanner not just as 2D images,
`but as positionally and orientationally identified slices
`within the relevant 3D space. In exemplary embodiments of
`the present invention, a user can convert such slices into
`volumes as desired, and can process the images or volumes
`using known image processing and/or volume rendering
`techniques. Alternatively, a user can acquire ultrasound
`images in 3D using the techniques of UltraSonar or 4D
`Ultrasound. In exemplary embodiments of the present
`invention, a user can manage various substantially real-time
`images that have been obtained, either as slices or volumes,
`and can control their visualization, processing and display,
`as well as their registration and fusion with other images,
`volumes or virtual objects obtained or derived from prior
`scans of the area or object of interest using various modali(cid:173)
`ties.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`[0013] FIG. 1 depicts a user controlling an exemplary
`ultrasound session with an exemplary pen and tablet two(cid:173)
`dimensional interface according to an exemplary embodi(cid:173)
`ment of the present invention;
`[0014] FIG. 2 depicts a user performing three-dimen(cid:173)
`sional interactions in a virtual patient space displayed ste(cid:173)
`reoscopically using an exemplary three-dimensional inter(cid:173)
`face according to an exemplary embodiment of the present
`invention;
`[0015] FIG. 3 depicts a user interacting with the three(cid:173)
`dimensional virtual patient space of FIG. 2, using a mono(cid:173)
`scopic interface according to an exemplary embodiment of
`the present invention;
`[0016] FIG. 4 depicts an exemplary illustrative scenario
`where three 3D ultrasound volumes are fused with three
`pre-operative segmentations in an exemplary composite
`view according to an exemplary embodiment of the present
`invention;
`[0017] FIG. 5 depicts exemplary user manipulations of
`the pre-operative segmentations and volume scans of FIG.
`4 according to an exemplary embodiment of the present
`invention;
`
`[0018] FIGS. 6A-6C depict exemplary preparations for a
`tumor removal procedure according to an exemplary
`embodiment of the present invention;
`[0019] FIG. 7 depicts an exemplary integrated system
`implementing an exemplary embodiment of the present
`invention;
`[0020] FIG. 8 depicts an exemplary external add-on sys(cid:173)
`tem implementing an exemplary embodiment of the present
`invention;
`[0021] FIGS. 9(a)-9(d) depict various exemplary pre-op(cid:173)
`erative scenarios according to an exemplary embodiment of
`the present invention;
`[0022] FIG. 9(e) depict an
`intra-operative scenario
`according to an exemplary embodiment of the present
`invention;
`[0023] FIG. 9(j) depict an alternative exemplary pre(cid:173)
`operative scenario according to an exemplary embodiment
`of the present invention;.
`[0024] FIGS. 9(g)-9(i) respectively depict alternative
`exemplary intra-operative scenarios according to an exem(cid:173)
`plary embodiment of the present invention;
`[0025] FIG. 10 depicts an exemplary system setup accord(cid:173)
`ing to an exemplary embodiment of the present invention;
`[0026] FIG. ll(a) depicts acquiring and storing a plurality
`of 2D ultrasound slices according to an exemplary embodi(cid:173)
`ment of the present invention;
`[0027] FIG. ll(b) depicts segmenting and blending the
`2D ultrasound slices of FIG. ll(a) to produce a 3D effect
`according to an exemplary embodiment of the present
`invention;
`[0028] FIG. 12 depicts scanned regions created in a vir(cid:173)
`tual space according to an exemplary embodiment of the
`present invention;
`[0029] FIG. 13 depicts an exemplary phantom used to
`illustrate an exemplary embodiment of the present inven(cid:173)
`tion;
`[0030] FIG.14 respectively depict an UltraSonar image, a
`reconstructed volumetric image, and a smoothed zoomed in
`and cropped volumetric image of the exemplary phantom of
`FIG. 13 according to an exemplary embodiment of the
`present invention;
`[0031] FIG. 15 depict space tracking of two liver scans
`according to an exemplary embodiment of the present
`invention; and
`[0032] FIG. 16 depicts an exemplary fusion of an ultra(cid:173)
`sound image in a single-plane with pre-operative CT data
`according to an exemplary embodiment of the present
`invention.
`[0033]
`It is noted that the patent or application file con(cid:173)
`tains at least one drawing executed in color. Copies of this
`patent or patent application publication with color drawings
`will be provided by the U.S. Patent Office upon request and
`payment of the necessary fee.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`[0034] This present invention is directed to a system and
`method for the management of a 3D space where substan-
`
`
`
`US 2006/0020204 Al
`
`Jan.26,2006
`
`3
`
`tially real-time images have been, or are being, acquired. For
`purposes of illustration, exemplary embodiments of the
`invention will be described with reference to ultrasound
`images, it being understood that any equivalent substantially
`real-time imaging modality can be used.
`
`[0035]
`In exemplary embodiments of the present inven(cid:173)
`tion a clinician can visualize images obtained from an
`ultrasound scanner not just as 2D images but as 2D slices
`within a particular 3D space ( or alternatively as volumes
`within such 3D space), each acquired at a known time, and
`can convert such 2D slices into volumes whenever needed.
`In exemplary embodiments of the present invention, the
`method allows a user to manage the different images
`obtained (either as slices or volumes), and to manipulate
`them as well as control various display parameters, for
`example, their visualization (including stereoscopically),
`registration and segmentation.
`
`[0036] Moreover,
`in exemplary embodiments of the
`present invention, a system can record for each acquired
`real-time image its 3D time and position. Therefore, in such
`exemplary embodiments, not only can a current image slice
`be displayed in its correct 3D position, but because the time
`of acquisition is available for each image, such methods also
`allow for the display of any previously acquired information
`at the given position. This allows for the visualization of
`time-variant processes, such as, for example, an injection of
`a contrast agent. For example, a contrast agent may be
`needed in order to characterize a particular lesion in liver
`tissue that may not be visible without it. During the time that
`the contrast agent is available in the relevant tissues, a
`system can record both the 3D position and the time of
`acquisition for each image. Later, for example, when a
`procedure is desired to be performed on the relevant tissue,
`such as, for example, a thermoablation, the recording of the
`tissue with the contrast agent flowing through it can be
`replayed (being co-registered to the ablation needle which
`can also be displayed in the 3D space, either within a current
`ultrasound slice, or by tracking the needle) to again visualize
`the lesion now no longer visible.
`
`[0037] Thus, in exemplary embodiments of the present
`invention, a user can manage the entire 3D space within
`which ultrasound scans from a particular scanning session
`are obtained in a way that leads to better diagnosis and/or
`intervention. It is noted that the disclosed method works
`without "co-location" of the ultrasound images with a real
`patient. The fusion in exemplary embodiments is between
`various images, as opposed to being between a virtual world
`and a real patient space such as is done in certain conven(cid:173)
`tional augmented reality techniques.
`
`[0038]
`In exemplary embodiments of the present inven(cid:173)
`tion a 3D interactive system is provided that can work with
`either ultrasound planes (shown in their respective 3D
`context), volumetric reconstructions of such ultrasound
`information, pre-operative imaging and planning data (e.g.,
`CT, MRI, planning pathways and selected objects in 3D data
`set, etc.) as well as other elements that can contribute to the
`procedure. This adds the ability to re-position ultrasound
`planes and other elements, such as an RF probe, more easily
`since the user can see a 3D space with "floating" objects and
`he can then, for example, simply move the needle or
`ultrasound probe to the 3D point where the floating object is
`perceived. This is in contrast to conventional systems, which
`
`neither provide an unrestricted display of an ultrasound ( or
`other substantially real-time scan) plane in the context of
`co-registered pre-scan data, nor allow a user to freely move
`within the 3D space in which the real-time scan is acquired.
`Thus in exemplary embodiments of the present invention the
`facility is provided to make full use of data from prior scans
`such as, for example, CT or other ultrasound imaging scans,
`of the same patient area in an integrated manner with the
`substantially real-time images.
`
`[0039]
`In exemplary embodiments of the present inven(cid:173)
`tion the coordinate positions of prior scan and real-time
`scans can be co-registered, allowing a user to interactively
`visualize the co-registered information in a way that is
`intuitive and precise. In so doing, acquired data can, for
`example, then be used to navigate a procedure, or later
`review a case. Such post procedural review is easily avail(cid:173)
`able because the 3D positions of the ultrasound planes are
`stored and can be analyzed after the ultrasound exploration.
`
`[0040] The disclosed method operates via registration of
`ultrasound images with a virtual patient-i.e., by registering
`pre-operative images and or segmentations therefrom with
`recently acquired ultrasound data of a given patient. Alter(cid:173)
`natively, the disclosed method can operate by registering one
`set of ultrasound data with one or more other sets of
`ultrasound data, either taken at different 3D positions, or at
`different times, or both. In either case, in exemplary embodi(cid:173)
`ments of the present invention, once various images are
`co-registered, fused images incorporating all or parts of the
`various co-registered images, as may be decided dynami(cid:173)
`cally by a user, can be interactively viewed and manipulated.
`Thus, for example, a user can perform, use or implement any
`of the techniques described in any of the pending patent
`applications incorporated by reference above while perform(cid:173)
`ing an ultrasound session or ultrasound guided procedure.
`For example, a user can resegment and adjust any display
`parameters for any pre-scan data relevant to the current
`focus of the ultrasound imaging. Vessels form an earlier CT
`scan can be cropped, segmented, assigned different color
`look-up table values, thresholded, etc. so as to focus the
`current---0r recent-area of interest in the ultrasound pro(cid:173)
`cedure. Alternatively pre-procedural planning notes, high(cid:173)
`lights and/or pathways can be dynamically and interactively
`brought up, hidden, or made more or less transparent as may
`be desired throughout the ultrasound session.
`
`[0041]
`In exemplary embodiments of the present inven(cid:173)
`tion, the disclosed method can be integrated with the fol(cid:173)
`lowing technologies: (a) visualization of 2D ultrasound
`slices into a volume without the need for volume resampling
`(and the concomitant resampling errors), as described more
`fully in "UltraSonar"; and (b) a virtual interface to substan(cid:173)
`tially real-time scanning machines, as described more fully
`in "Virtual Interface."
`
`[0042] Thus, in exemplary embodiments of the present
`invention, a special virtual interface can be used to control
`an interactive ultrasound scanning session. Additionally,
`ultrasound probes and instruments can, for example, be
`tracked by a 3D tracking system so that the each of the
`probes' and instruments' respective 3D positions and ori(cid:173)
`entations can be known at all times during the ultrasound
`scan.
`
`[0043] Moreover, as noted, ultrasound scanning can, for
`example, be preceded by pre-operative CT or MR imaging
`
`
`
`US 2006/0020204 Al
`
`Jan.26,2006
`
`4
`
`in which, for example, a segmentation of various objects or
`a "signature" of various organs or organelles (such as, for
`example, the vascular system of a liver or kidney) can be
`extracted to identify geometrical and topological compo(cid:173)
`nents that can define the anatomy and pathology of the
`specific patient under treatment. Such a characteristic can be
`subsequently utilized to maintain registration between pre(cid:173)
`operative data and real-time ultrasound scanning images or
`volumes.
`
`[0044] Also, during ultrasound scanning, acquired images
`can, for example, be visualized using the
`techniques
`described in UltraSonar. This technique, by allowing the
`display of a certain number of past ultrasound slices to only
`slowly fade away, can allow a user to visualize 2D ultra(cid:173)
`sound slices as "pseudo-volumes" without the need for
`time-consuming re-sampling into actual 3D volumes and
`subsequent volume rendering.
`
`Control and Display Interfaces
`
`[0045]
`the
`to
`In exemplary embodiments according
`present invention a pen-and-tablet interface can be used for
`2D control, as depicted in FIG. 1. With reference thereto, a
`user 100 can, for example, physically manipulate a pen 110
`and table 120, and can thus interact with a virtual keyboard
`as shown at the bottom of display 130, in similar fashion as
`described in Virtual Interface or in A Display Apparatus.
`Thus, control commands such as, for example, pushing or
`selecting menu bars, typing in text, selecting between menu
`options, etc. can be mapped from the displayed virtual
`keyboard to 2D manipulations of the pen and tablet. The pen
`and table can utilize a 2D tracking device for this purpose.
`
`[0046] For 3D control, a 3D interface can be used as
`depicted in FIG. 2. With reference thereto, in exemplary
`embodiments of the present invention the entire interface
`can utilize a stereoscopic display 230 (note how the depicted
`scan jumps out of the screen, simulating the stereoscopic
`effect) inasmuch as this can afford superior depth perception,
`which is the key to any 3D interface. However, in alternate
`exemplary embodiments of the present invention the method
`can also be operated using a standard monoscopic interface
`330, as shown in FIG. 3, thus allowing more or less standard
`equipment to be used in, for example, more economic or
`retrofit implementations of exemplary embodiments of the
`present invention.
`
`3D Manipulations in 3D space
`
`[0047]
`the
`to
`In exemplary embodiments according
`present invention, greater control and integrated imaging
`and display management of a 3D space where substantially
`real-time imaging is performed can be enabled. For purposes
`of illustration, in what follows an exemplary ultrasound
`scanning of a liver with a lesion (tumor) will be described.
`In the following description, it is assumed, for example, that
`a patient has had a pre-operative CT scan of his liver, and
`during a subsequent surgical planning session,
`three
`"objects" were identified by the clinician, as depicted in
`FIG. 4. These objects are (i) a vessel defined by three
`terminal points (A, B, C) and a central "hub" (point D), all
`connected together; (ii) a lesion L; and (iii) an adjacent
`organ 0, for example a kidney, that serves as an anatomical
`landmark.
`
`[0048] These three objects can, for example, be defined
`geometrically in a segmentation process and can thus be
`represented by polylines, polygonal meshes, and/or other
`graphical representations.
`
`[0049] Given this exemplary pre-scan history, in an ultra(cid:173)
`sound scanning session a clinician can, for example, perform
`three corresponding volumetric ultrasound scans using, for
`example, an ultrasound probe with a 3D tracker. This
`process is illustrated in the upper right quadrant of FIG. 4.
`These scans can be, for example, with reference to FIG. 4,
`Scan 1 of blood vessel ABCD ( obtained at time T 1 , when a
`contrast medium is flowing through it, for example, at the
`arterial phase); Scan 2 of a lesion ( obtained at time T 2 , when
`the contrast medium has filled the liver and the lesion shows
`more signal (i.e., the liver is full of contrast and thus the
`lesion echoes back stronger to the ultrasound probe), for
`example, in the portal phase); and Scan 3 of the organ
`( obtained at yet another time T 3 , at a basal phase, and at a
`different angle from the other two scans). Such an organ
`could be, for example, a kidney that can be seen without
`contrast. These scans can then be stored for subsequent
`manipulations.
`
`[0050] Alternatively, a user could scan a given area mul(cid:173)
`tiple times using different ultrasound probes, where each has
`different acquisitional properties, and can, for example, store
`the scans according to the methods of the present invention.
`Just as in the case of using a single probe at different times
`with contrast, the multiple scans of the same area with the
`different probes will acquire different images which can then
`be fused to exploit the informational benefits of each probe
`type yet display then simultaneously in a synoptic view.
`
`[0051]
`In order to fully use the information obtained from
`such scans, in exemplary embodiments of the present inven(cid:173)
`tion the pre-operative segmentations can, for example, be
`registered with the patient. This can be done, for example, by
`means of fiducial markers placed on the skin of the patient,
`or by any other known means.