U.S. patent application number 12/205599 was filed with the patent office on 2010-03-11 for method and apparatus for catheter guidance using a combination of ultrasound and x-ray imaging.
Invention is credited to William Alphonsus Zang, Anne Lindsay Hall, Michael Washburn.
Application Number | 20100063400 12/205599 |
Document ID | / |
Family ID | 41799859 |
Filed Date | 2010-03-11 |
United States Patent
Application |
20100063400 |
Kind Code |
A1 |
Hall; Anne Lindsay ; et
al. |
March 11, 2010 |
METHOD AND APPARATUS FOR CATHETER GUIDANCE USING A COMBINATION OF
ULTRASOUND AND X-RAY IMAGING
Abstract
An apparatus for tracking movement of a foreign object within a
subject has an X-ray fluoroscopic system with an X-ray detector and
an ultrasound system that has a probe with a position sensor. A
display is configured to display a static X-ray image acquired by
the X-ray fluoroscopic system and a real-time ultrasound image
acquired by the ultrasound system. The X-ray image and the
ultrasound image each display at least a portion of the foreign
object and at least a portion of surrounding area. A tracking
module is configured to track movement of the foreign object within
the ultrasound image and the display is further configured to
display an indication of the movement of the foreign object on the
X-ray image
Inventors: |
Hall; Anne Lindsay; (New
Berlin, WI) ; Washburn; Michael; (Brookfield, WI)
; Alphonsus Zang; William; (Cedarburg, WI) |
Correspondence
Address: |
DEAN D. SMALL;THE SMALL PATENT LAW GROUP LLP
225 S. MERAMEC, STE. 725T
ST. LOUIS
MO
63105
US
|
Family ID: |
41799859 |
Appl. No.: |
12/205599 |
Filed: |
September 5, 2008 |
Current U.S.
Class: |
600/466 ;
378/4 |
Current CPC
Class: |
A61B 8/0841 20130101;
A61B 8/4254 20130101; A61B 8/481 20130101; A61B 2090/378 20160201;
A61B 6/504 20130101; A61B 8/469 20130101; A61B 8/14 20130101; A61B
8/0891 20130101; A61B 8/0833 20130101; A61B 6/464 20130101; A61B
6/481 20130101; A61B 8/5238 20130101; A61B 8/464 20130101; A61B
8/5261 20130101; A61B 34/20 20160201; A61B 8/483 20130101; A61B
6/4417 20130101; A61B 8/463 20130101; A61M 25/09 20130101; A61B
8/4416 20130101; A61B 2090/376 20160201; A61B 6/469 20130101; A61B
8/4472 20130101; A61B 6/463 20130101; A61B 6/12 20130101; A61B
6/5247 20130101 |
Class at
Publication: |
600/466 ;
378/4 |
International
Class: |
A61B 8/14 20060101
A61B008/14; A61B 6/00 20060101 A61B006/00 |
Claims
1. An apparatus for tracking movement of a foreign object within a
subject, the apparatus comprising: an X-ray fluoroscopic system
comprising an X-ray detector; an ultrasound system comprising a
probe having a position sensor; a display configured to display a
static X-ray image acquired by the X-ray fluoroscopic system and a
real-time ultrasound image acquired by the ultrasound system, the
X-ray image and the ultrasound image each displaying at least a
portion of the foreign object and at least a portion of surrounding
area; and a tracking module configured to track movement of the
foreign object within the ultrasound image, the display further
configured to display an indication of the movement of the foreign
object on the X-ray image.
2. The apparatus of claim 1, further comprising one of a wired
connection and a wireless connection interconnecting the X-ray
fluoroscopic system and the ultrasound system, the wired or
wireless connection configured to convey at least imaging data
between the ultrasound system and the X-ray fluoroscopic
system.
3. The apparatus of claim 1, wherein the ultrasound system and the
X-ray fluoroscopic system are integrated together into one
system.
4. The apparatus of claim 1, further comprising a user input for
identifying a tip of the foreign object on at least one of the
X-ray image and the ultrasound image.
5. The apparatus of claim 1, further comprising a processor
configured to automatically identify a tip of the foreign object on
at least one of the X-ray image and the ultrasound image.
6. The apparatus of claim 1, further comprising a registration
module configured to register the X-ray and ultrasound images with
respect to each other based on at least one point identified in
each of the X-ray and ultrasound images.
7. The apparatus of claim 1, wherein the indication of the movement
on the X-ray image is one of a number, a line, a dotted line,
displayed in a different color than a color of the foreign object
in the X-ray image, and displayed in a different intensity than an
intensity of the foreign object in the X-ray image.
8. The apparatus of claim 1, wherein the display is further
configured to display a projection of a face of the probe on the
X-ray image.
9. The apparatus of claim 1, wherein the X-ray image is a
contrast-enhanced X-ray image.
10. A method for positioning a guide wire within a subject, the
method comprising: displaying a static X-ray image comprising at
least a tip of a guide wire and vessels indicated by contrast;
displaying a live ultrasound image comprising at least the tip of
the guide wire and at least a portion of the vessels; identifying
the guide wire on both the X-ray image and the ultrasound image;
and indicating movement of the guide wire on the X-ray image based
on movement of the guide wire detected in the ultrasound image.
11. The method of claim 10, further comprising: receiving inputs
associated with the X-ray image and the ultrasound image; and
registering the X-ray and ultrasound images based on the
inputs.
12. The method of claim 10, the identifying further comprising
identifying a region of interest associated with the X-ray image,
the tip of the guide wire being automatically detected within the
region of interest.
13. The method of claim 10, further comprising displaying the X-ray
image and the ultrasound image simultaneously on one of a single
display and two displays positioned side-by-side.
14. The method of claim 10, wherein the ultrasound image comprises
one of a projection image, a 2D dataset and a 3D dataset, the
method further comprising: combining the ultrasound image and the
X-ray image; and displaying at least the combined image.
15. The method of claim 10, wherein the ultrasound image is a plane
representative of ultrasound data from within a 3D volume of data,
the method further comprising at least one of displaying the plane
overlaid on the X-ray image and displaying the plane simultaneously
with the X-ray image.
16. The method of claim 10, further comprising: acquiring a
subsequent X-ray image, the subsequent X-ray image displaying at
least the tip of the guide wire; and combining the subsequent X-ray
image and the X-ray image to display a new position of the tip of
the guide wire.
17. The method of claim 10, further comprising: acquiring at least
one subsequent X-ray image, the at least one subsequent X-ray image
displaying the guide wire; deleting the guide wire on the X-ray
image; and combining the subsequent X-ray image and the X-ray
image.
18. An apparatus for positioning a guide wire within the
vasculature of a subject, the apparatus comprising: an X-ray
detector configured to detect X-rays that are generated by an X-ray
tube and transmitted through the subject; an ultrasound probe
comprising a position sensor; at least one display configured to
display a static contrast-enhanced X-ray image detected by the
X-ray detector and a real-time ultrasound image acquired by the
ultrasound probe, the X-ray image and the ultrasound image
displaying at least a portion of a guide wire; and a registration
module configured to register the X-ray and ultrasound images with
respect to each other based on a point identified in each of the
X-ray and ultrasound images, the display further configured to
display an indication of movement of the guide wire on the X-ray
image based on movement of the guide wire detected within the
ultrasound image.
19. The apparatus of claim 18, wherein the X-ray detector is
further configured to acquire a subsequent X-ray image, the
subsequent X-ray image displaying at least a tip of the guide wire,
the display further configured to combine the subsequent X-ray
image and the X-ray image.
20. The apparatus of claim 18, wherein the X-ray detector is
further configured to acquire a subsequent X-ray image, the
subsequent X-ray image displaying at least a tip of the guide wire,
the display further configured to combine the subsequent X-ray
image and the X-ray image and to indicate the guide wire of the
subsequent X-ray image differently than the guide wire of the X-ray
image.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates generally to dual modality imaging
and more particularly to vascular interventional radiology.
[0002] Vascular interventional radiology often involves angioplasty
using a balloon catheter. Once in place, such as in an area of
stenosis, the balloon is inflated, compressing the plaque against
the walls of the vessel with the purpose of creating a larger
lumen. Traditionally, fluoroscopy is used to track the insertion of
a guide wire in real-time to an area in which the balloon catheter
will be deployed. Vasculature is not visible on the fluoroscopic
images, and thus a bolus of contrast is often injected through a
guidance catheter to provide an image of the arterial tree. Precise
guidance of the guide wire and catheter are needed to avoid damage
to anatomical structures.
[0003] As the positioning of the guide wire involves real-time
fluoroscopic imaging, the subject or patient typically receives a
high dose of radiation over the course of the procedure, as do
persons standing nearby. In addition, the contrast agent is quickly
cleared by the body, and thus multiple doses of contrast are often
injected, which in some cases may result in contrast induced
nephrotoxicity, as well as additional cost.
BRIEF DESCRIPTION OF THE INVENTION
[0004] In one embodiment, an apparatus for tracking movement of a
foreign object within a subject has an X-ray fluoroscopic system
with an X-ray detector and an ultrasound system that has a probe
with a position sensor. A display is configured to display a static
X-ray image acquired by the X-ray fluoroscopic system and a
real-time ultrasound image acquired by the ultrasound system. The
X-ray image and the ultrasound image each display at least a
portion of the foreign object and at least a portion of surrounding
area. A tracking module is configured to track movement of the
foreign object within the ultrasound image and the display is
further configured to display an indication of the movement of the
foreign object on the X-ray image.
[0005] In another embodiment, a method for positioning a guide wire
within a subject comprises displaying a static X-ray image
comprising at least a tip of a guide wire and vessels indicated by
contrast. A live ultrasound image is displayed that includes at
least the tip of the guide wire and at least a portion of the
vessels. The guide wire is identified on both the X-ray image and
the ultrasound image. Movement of the guide wire is indicated on
the X-ray image based on movement of the guide wire that is
detected in the ultrasound image.
[0006] In yet another embodiment, an apparatus for positioning a
guide wire within the vasculature of a subject has an X-ray
detector configured to detect X-rays that are generated by an X-ray
tube and transmitted through a subject. An ultrasound probe has a
position sensor. At least one display is configured to display a
static contrast-enhanced X-ray image that is detected by the X-ray
detector and a real-time ultrasound image that is acquired by the
ultrasound probe. The X-ray image and the ultrasound image display
at least a portion of a guide wire. A registration module is
configured to register the X-ray and ultrasound images with respect
to each other based on a point identified in each of the X-ray and
ultrasound images. The display is further configured to display an
indication of movement of the guide wire on the X-ray image based
on movement of the guide wire detected within the ultrasound
image.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 illustrates an ultrasound system interconnected with
an X-ray fluoroscopic system formed in accordance with an
embodiment of the present invention.
[0008] FIG. 2 illustrates a method for tracking movement of a
foreign object on an image acquired by a first imaging system based
on movement of the object within an image acquired by a second
imaging system in accordance with an embodiment of the present
invention.
[0009] FIG. 3 illustrates a contrast-enhanced X-ray image on a
display that shows the vascular tree pattern and a guide wire and
guidance catheter inserted into a vessel in accordance with an
embodiment of the present invention.
[0010] FIG. 4 illustrates the X-ray image and a real-time
ultrasound image showing a guide wire in accordance with an
embodiment of the present invention.
[0011] FIG. 5 illustrates the X-ray image and a real-time
ultrasound projection image in accordance with an embodiment of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0012] 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 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.
[0013] 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 of 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.
[0014] FIG. 1 illustrates an ultrasound system interconnected with
an X-ray fluoroscopic system in accordance with an embodiment of
the present invention. A table 100 or bed is provided for
supporting a subject 102. An X-ray tube 104 or other generator is
connected to an X-ray fluoroscopic system 106. As shown, the X-ray
tube 104 is positioned above the subject 102, but it should be
understood that the X-ray tube 104 may be moved to other positions
with respect to the subject 102. A detector 108 is positioned
opposite the X-ray tube 104 with the subject 102 there-between. The
detector 108 may be any known detector capable of detecting X-ray
radiation.
[0015] The X-ray fluoroscopic system 106 has at least a memory 110,
a processor 112 and at least one user input 114, such as a
keyboard, trackball, pointer, touch panel, and the like. To acquire
an X-ray image, the X-ray fluoroscopic system 106 causes the X-ray
tube 104 to generate X-rays and the detector 108 detects an image.
Fluoroscopy may be accomplished by activating the X-ray tube 104
continuously or at predetermined intervals while the detector 108
detects corresponding images. Detected image(s) may be displayed on
a display 116 that may be configured to display a single image or
more than one image at the same time.
[0016] An ultrasound system 122 communicates with the X-ray
fluoroscopic system 106 via a connection 124. The connection 124
may be a wired or wireless connection. The ultrasound system 122
may transmit or convey ultrasound imaging data to the X-ray
fluoroscopic system 106. The communication between the systems 106
and 122 may be one-way or two-way, allowing image data, commands
and information to be transmitted between the two systems 106 and
122. The ultrasound system 122 may be a stand-alone system that may
be moved from room to room, such as a cart-based system,
hand-carried system, or other portable system.
[0017] An operator (not shown) may position an ultrasound probe 126
on the subject 102 to image an area of interest within the subject
102. The ultrasound probe 126 has a position sensor 142. The
ultrasound system 122 has at least a memory 128, a processor 130,
and a user input 132. Optionally, if the ultrasound system 122 is a
stand-alone system, a display 134 may be provided. By way of
example, images acquired using the X-ray fluoroscopic system 106
may be displayed as a first image 118 and images acquired using the
ultrasound system 122 may be displayed as a second image 120 on the
display 116, forming a dual display configuration. In another
embodiment, two side-by-side monitors (not shown) may be used. The
images acquired by both the X-ray fluoroscopic system 106 and the
ultrasound system 122 may be acquired in known manners.
[0018] In one embodiment, the ultrasound system 122 may be a
3D-capable miniaturized ultrasound system that is connected to the
X-ray fluoroscopic system 106 via the connection 124. As used
herein, "miniaturized" means that the ultrasound system 122 is
configured to be carried in a person's hand, pocket,
briefcase-sized case, or backpack. For example, the ultrasound
system 122 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. The ultrasound system 122 may
weigh about ten pounds, and thus is easily portable by the
operator. An integrated display, such as the display 134, may be
configured to display an ultrasound image as well as an X-ray image
acquired by the X-ray fluoroscopic system 106.
[0019] As another example, the ultrasound system 122 may be a 3D
capable pocket-sized ultrasound system. By way of example, the
pocket-sized ultrasound system may be approximately 2 inches wide,
approximately 4 inches in length, and approximately 0.5 inches in
depth and weigh less than 3 ounces. The pocket-sized ultrasound
system may include a display (e.g. the display 134), a user
interface (e.g. user input 132) and an input/output (I/O) port for
connection to the probe 126. It should be noted that the various
embodiments may be implemented in connection with a miniaturized or
pocket-sized ultrasound system having different dimensions,
weights, and power consumption.
[0020] In another embodiment, the ultrasound system 122 may be a
console-based ultrasound imaging system provided on a movable base.
The console-based ultrasound imaging system may also be referred to
as a cart-based system. An integrated display (e.g. the display
134) may be used to display the ultrasound image alone or
simultaneously with the X-ray image as discussed herein.
[0021] In yet another embodiment, the X-ray fluoroscopic system 106
and the ultrasound system 122 may be integrated together and may
share at least some processing, user input and memory functions.
For example, a probe port 136 may be provided on the table 100 or
other apparatus near the subject 102. The probe 126 may thus be
connected to the probe port 136.
[0022] A registration module 138 may be used to register the first
and second images 118 and 120 with respect to each other, and a
tracking module 140 may be used to track a foreign object, such as
a guide wire, within one of the images, which is a live image. The
movement of the foreign object is indicated within a corresponding
static image. In one example, the live image is an ultrasound image
and the static image is an X-ray image. Although shown within the
X-ray fluoroscopic system 106, the registration module 138 and the
tracking module 140 may be within the ultrasound system 122 or
within a separate module or system.
[0023] FIG. 2 illustrates a method for tracking movement of a
foreign object on an image acquired by a first imaging system based
on movement of the object within an image acquired by a second
imaging system. The foreign object may be any object inserted into
the body such as a guide wire, a tip of the guide wire, or a
catheter. In this example the two different imaging systems are the
X-ray fluoroscopic system 106 and the ultrasound system 122, both
shown in FIG. 1. In another embodiment, a different modality, such
as a Magnetic Resonance Imaging (MRI) system or a Computer
Tomography (CT) system may be used with the ultrasound system
122.
[0024] At 200, the first and second imaging systems are
interconnected. For example, connection 124 may be used to connect
the X-ray fluoroscopic system 106 and the ultrasound system 122
either through a wire or cable, or wirelessly. In another
embodiment, if the two imaging systems are integrated into a single
system, the probe 126 may be connected to the probe port 136.
[0025] At 202 real-time X-ray and/or fluoroscopy are used to
provide images for initially positioning a guide wire and guidance
catheter to a central location in the vascular system of the
subject 102. The central location may be determined by the ultimate
desired position of a balloon catheter or a position where other
action is desired or needed. The fluoroscopic or X-ray images may
be displayed as the first image 118 on the display 116.
[0026] When the tip of the guide wire has reached the desired
initial position, at 204 a bolus of radio-opaque contrast agent is
introduced through the guidance catheter. At 206, an X-ray image
displaying the location of the guide wire and guidance catheter, as
well as the vascular tree pattern, is captured and displayed on the
display 116 as the first image 118. Therefore, the fluoroscopic
image used when initially positioning the guide wire may be
replaced on the display 116 by a contrast-enhanced X-ray image. By
way of example, the contrast-enhanced X-ray image may be a single
fluoroscopic frame, a single X-ray frame, or a digital subtraction
angiographic image, where the resulting image is the difference
between a pre-contrast and post-contrast injection image. It should
be understood that other types of images may be used. In one
embodiment, the ultimate desired position of the balloon catheter
within the vascular system may be within the contrast-enhanced
X-ray image.
[0027] FIG. 3 illustrates a contrast-enhanced X-ray image 150 in
accordance with an embodiment of the invention on the display 116
that shows a vascular tree pattern 146 as well as a guide wire 152
and a guidance catheter 154 inserted into a vessel 144. Returning
to FIG. 2, at 208 a tip 156 (shown in FIG. 3) of the guide wire 152
is identified. The tip 156 may be the outermost end of the guide
wire 152. For example, the operator may use the user input 114,
such as a cursor, to select the tip 156. Alternatively, the
processor 112 may automatically detect the tip 156 using, for
example, boundary detection or other recognition type of algorithm
that searches for the guide wire 152, or may detect the guide wire
152 based on a level of brightness in the X-ray image 150. Other
automatic detection methods and algorithms may be used. In one
embodiment, automatic detection may be accomplished within a user
defined area or region of interest 158, while in another embodiment
automatic detection may be accomplished across the entire X-ray
image 150.
[0028] At 210 the operator scans the subject 102 with the
ultrasound probe 126, and at 212 the live ultrasound image is
displayed on the display 116 as the second image 120. FIG. 4
illustrates the X-ray image 150 and a real-time ultrasound image
160 showing the guide wire 152. By way of example only, the
ultrasound image 160 may be a B-mode image. At 214 of FIG. 2, tip
162 (shown in FIG. 4) of the guide wire 152 is identified in the
ultrasound image 160. The operator may identify the tip 162 using
the one of the user inputs 114 or 132, or the tip 162 may be
automatically identified through automatic image processing.
[0029] The X-ray image 150 has a fixed geometry based on the X-ray
fluoroscopic system 106 that is known, and therefore the position
and/or orientation of the guide wire 152 and tip 156 within the
X-ray image 150 are also known. Using position information from the
position sensor 142 of the probe 126 and the identified locations
of the tips 156 and 162 in the images 150 and 160, at 216 the
registration module 138 registers the X-ray image 150 and the
ultrasound image 160 with respect to each other. Registration of
the two images 150 and 160 may be accomplished using any
registration process available for registering images acquired
using two different modalities and/or two different imaging
systems. For example, auto registration and correlation processes
may be used based on anatomical similarities.
[0030] In another embodiment, an anatomical point that is
visualized in both the X-ray image 150 and the ultrasound image 160
may be defined and/or selected, and may be used as the registration
point. For example, the operator may select an intersection of two
or more vessels on each of the images 150 and 160 and the
registration module 138 may register the two images based on the
two selected points.
[0031] The operator then, at 218, adjusts the position of the guide
wire 152, feeding the guide wire 152 towards the point or area of
interest. The operator may watch the motion of the guide wire 152
in real-time on the ultrasound image 160 while using the X-ray
image 150 that shows the vascular tree pattern 146 as a base or
reference image. The probe 126 may be moved or adjusted as
necessary to view the anatomy of interest. In some embodiments, the
tip 162 of the guide wire 152 may be indicated on the ultrasound
image 160 with an indicator (not shown), and the processor 112 or
130 may automatically update the indicator as the tip 162 moves
within the ultrasound image 160.
[0032] At 220 the tracking module 140 detects movement of the tip
162 of the guide wire 152 in the ultrasound image 160 and a new
position of the corresponding tip 156 of the guide wire 152 is
indicated on the X-ray image 150. For example, a position sensor
(not shown) may be mounted to or integrated with the tip of the
guide wire 152. The guide wire position sensor reading may be used
to update the position on the X-ray image 150 as well as in the
ultrasound image. In cases where the guide wire 152 is outside of
the current ultrasound image, the position may be projected onto
the ultrasound image with the relative location reflected in the
graphical appearance of the projection. For example, the position
sensor may transmit spatial location information wirelessly or
through the guide wire 152. Alternatively, image processing and/or
algorithms that may automatically identify the guide wire 152 in
the ultrasound image 160, such as at 214, may be used to
automatically track movement of the tip 162 of the guide wire 152.
In another embodiment, after adjusting the guide wire 152 to a new
location, the operator may identify the new location of the tip 162
on the ultrasound image 160 using one of the user inputs 114 or
132. The processor 112 and/or tracking module 140 then determine
and indicate the corresponding location of the tip 156 on the X-ray
image 150. It should be understood that other methods may be used
to track, detect, and locate the position of the tip 162 of the
guide wire 152 in the ultrasound image 160.
[0033] For example, the operator may advance the guide wire 152 to
point 164 as shown on the ultrasound image 160 of FIG. 4. The
movement of the guide wire 152 is indicated on the X-ray image 150
as dotted line 166. The indication on the display 116 may be a
line, a dotted line, a dot, point, character such as an "X" or
other indicator. In another embodiment, the indication may be
displayed in a color or may have a different or predetermined
intensity. In yet another embodiment, the indication may be a
number that is used to indicate a location or to indicate movement
based on time, distance, and the like, or any other indication that
is visible to the operator so that the operator may track the
real-time progress of the guide wire 152 on the static X-ray image
150.
[0034] The method loops between 218 and 220 to continuously detect
(and possibly separately indicate) movement of the tip 162 of the
guide wire 152 within the ultrasound image 160 and to indicate the
movement of the corresponding tip 156 on the X-ray image 150. It
should be understood that other foreign objects may be tracked and
indicated in the same manner.
[0035] Once the tip 162 of the guide wire 152 is positioned in the
desired region of the vessel, the operator may take further action
based on the treatment or procedure. For example, the guidance
catheter may be removed and a balloon catheter may be inserted
using the guide wire 152 to position the balloon catheter, such as
for angioplasty. Other interventional vascular procedures may be
performed, such as ablation, biopsy and the like.
[0036] In one embodiment, a projection 168 (shown on FIG. 4) of the
face of the probe 126 may be displayed on the X-ray image 150. The
projection 168 is based on the particular probe 126 being used and
thus may be a rectangle, as shown, a square or other shape. For
example, the orientation of the probe 126 may be specified by the
operator or the orientation of the probe face may be specified by
using a fixed orientation during the specification of a common
point, such as the tips 156 and 162. Alternatively, a graphic may
be adjusted to match the current probe orientation, or the same
point in the ultrasound image 160 may be marked from three or more
probe face orientations. The projection 168 may be updated based on
movement detected by the position sensor 142.
[0037] In some situations, the operator may wish to update the
X-ray image 150 with a new subsequent X-ray image showing the
vascular tree and the current position of the guide wire 152. The
method may thus return to 204, wherein a new bolus of X-ray
contrast agent is introduced. The subsequent x-ray image may
replace the X-ray image 150. The tip 156 on the X-ray image 150 and
optionally, the tip 162 on the ultrasound image 160, may be
redefined, and the operator continues to advance the guide wire 152
as desired. Alternatively, the current guide wire indication(s) may
be retained from the prior X-ray image(s).
[0038] In another embodiment, the operator may wish to update the
X-ray image 150 to redefine the guide wire location without
redefining or showing the vascular tree. In this example, a new
contrast bolus is not used and thus a subsequent X-ray image is
captured that does not display the vascular tree. The subsequent
X-ray image may be fused with the X-ray image 150 to update the
position of the guide wire 152. If multiple X-ray images are taken
over time, multiple guide wires may be superimposed onto the same
image. Each of the guide wires may be auto-detected and numbered
(or otherwise indicated differently with respect to each other) to
provide information regarding the most recent position as well as
previous positions. Alternatively, the guide wire 152 may be
removed or deleted from one or more previous images to display only
the most recent guide wire 152 or to indicate the most recent
position of the tip 156. In another embodiment, the guide wire
indications may each be toggled on and off, such as to track the
movement of the guide wire from one image to the next.
[0039] In some embodiments the ultrasound system 122 and probe 126
may be capable of real-time 3D imaging, also known as 4D imaging.
The real-time 3D image data may be displayed on the display 116,
such as in a volume, to allow real-time 3D tracking of the guide
wire.
[0040] The real-time 3D image data may also be displayed in any
other 3D display method known in the art, such as maximum
projection, average projection and surface rendering. FIG. 5
illustrates the X-ray image 150 and a real-time ultrasound
projection image 180. The ultrasound system 122 collects real-time
3D imaging data, using a 3D capable probe that has the position
sensor 142. As discussed previously, the operator selects the tip
156 on the X-ray image 150 and the tip 162 on the ultrasound image.
Alternatively, one or both of the tips 156 and 162 may be
automatically identified. The ultrasound image may be a B-mode
ultrasound image 160 as previously discussed. The registration
module 138 registers the two images with respect to each other, and
the processor 112 forms an ultrasound projection image 180 that has
the same orientation as the X-ray image 150.
[0041] In one embodiment, the projection image 180 is scaled
geometrically to match the geometry of the X-ray image 150. In this
example, processor 112 may automatically determine or the operator
may input one or more anatomical landmarks or points that are used
to determine scaling, and possibly orientation, of the images 150
and 180. The projection image 180 may then be combined with the
X-ray image 150. For example, the projection image 180 may be fused
with or overlaid on the X-ray image 150. Optionally, the X-ray
image 150 may be overlaid on the projection image 180. The motion
of the guide wire 152 may then be visually observed as the guide
wire 152 and tip 162 move along the X-ray contrast opaque vessels.
In a different embodiment, the projection image 180 is displayed
separately from the X-ray image 150 as shown in FIG. 5, and the
tracking module 140 tracks the movement of the guide wire 152 on
the X-ray image 150 as discussed previously. In another embodiment,
the display 116 may display more than two images, such that one or
both of the X-ray and projection images 150 and 180 may be
displayed simultaneously with a combined X-ray and projection
image.
[0042] Other ultrasound images may be formed and displayed, such as
a C-plane or other plane through the ultrasound volume. In the
example of the C-plane, the probe 126 is positioned in the same
orientation as the X-ray tube 104, such that the C-plane or slice
is perpendicular to the direction of the X-rays. The C-plane may be
oriented and scaled geometrically to match the X-ray image 150
orientation and dimensions, and may be overlaid on the X-ray image
150. The operator may then modify the depth of the C-plane that is
displayed, allowing tracking of the movement of the guide wire 152
in the depth direction. If displaying a plane that is not the
C-plane, the operator may adjust the position of the plane, but
this may not correlate with the depth as defined by the orientation
of the X-ray image 150. As with the ultrasound projection image
180, the C-plane or other plane may be displayed simultaneously
with the X-ray image 150 and/or simultaneously with an image that
combines the X-ray image 150 and the ultrasound plane.
[0043] In another embodiment, the ultrasound system 122 may acquire
2D ultrasound image data. Alternatively, a slice or plane of 2D
ultrasound data may be selected from an acquired ultrasound volume.
The 2D dataset may be overlaid, fused or otherwise combined with
the X-ray image 150 (or the X-ray image 150 may be overlaid on the
2D dataset) and displayed on the display 116 as a single image.
[0044] In addition to tracking the guide wire 152, the ultrasound
system 122 may be used to evaluate a procedure immediately, such as
immediately post-angioplasty, to non-invasively document the
absence of a flow reducing stenosis or to identify additional areas
of concern. For example, B-mode, color and spectral Doppler modes
and the like may be used. Also, the use of the ultrasound system
122 may lead to less mistakes in the navigation of the guide wire
152.
[0045] In another embodiment, once the guide wire 152 has been
advanced to the initial position, such as at 202 of FIG. 2,
ultrasound contrast agent may be introduced into the subject 102. A
3D ultrasound vascular image may then be acquired and used as the
base or reference image rather than the contrast-enhanced X-ray
image 150. The ultrasound vascular image may be, for example, a
rendered ultrasound image of the contrast agent or a projection
image, and is used together with the live ultrasound image 160 for
guidance of the guide wire 152.
[0046] A technical effect of at least one embodiment is the ability
to guide the movement and placement of a guide wire and/or catheter
or other foreign object using two imaging modalities at the same
time. One imaging modality may be X-ray fluoroscopy in which a
bolus of contrast agent is introduced so that the vascular tree may
be imaged and displayed. The other imaging modality may be
ultrasound wherein the static contrast-enhanced X-ray image and the
real-time ultrasound image are registered with respect to each
other. The operator may then utilize both the X-ray image and the
real-time ultrasound image to advance the guide wire. The amount of
contrast that needs to be given to the subject may be decreased,
thus decreasing the possible side effects of the contrast, such as
nephrotoxicity. Also, because fluoroscopy is not being continuously
performed throughout the procedure, the operator, subject and other
staff receive less X-ray radiation compared to procedures conducted
using only X-ray.
[0047] It is to be understood that the above description is
intended to be illustrative, and not restrictive. For example, the
above-described embodiments (and/or aspects thereof) may be used in
combination with each other. In addition, many modifications may be
made to adapt a particular situation or material to the teachings
of the invention without departing from its scope. While the
dimensions and types of materials described herein are intended to
define the parameters of the invention, they are by no means
limiting and are exemplary embodiments. Many other embodiments will
be apparent to those of skill in the art upon reviewing the above
description. The scope of the invention should, therefore, be
determined with reference to the appended claims, along with the
full scope of equivalents to which such claims are entitled. In the
appended claims, the terms "including" and "in which" are used as
the plain-English equivalents of the respective terms "comprising"
and "wherein." Moreover, in the following claims, the terms
"first," "second," and "third," etc. are used merely as labels, and
are not intended to impose numerical requirements on their objects.
Further, the limitations of the following claims are not written in
means-plus-function format and are not intended to be interpreted
based on 35 U.S.C. .sctn.112, sixth paragraph, unless and until
such claim limitations expressly use the phrase "means for"
followed by a statement of function void of further structure.
[0048] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
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