U.S. patent number RE45,534 [Application Number 13/865,803] was granted by the patent office on 2015-06-02 for vascular image co-registration.
This patent grant is currently assigned to Volcano Corporation. The grantee listed for this patent is Volcano Corporation. Invention is credited to Vincent J. Burgess, Stephen M. Fry, Richard Scott Huennekens, William R. Kanz, Jon D. Klingensmith, Nancy Perry Pool, Blair D. Walker.
United States Patent |
RE45,534 |
Huennekens , et al. |
June 2, 2015 |
**Please see images for:
( Certificate of Correction ) ** |
Vascular image co-registration
Abstract
A system and method for providing a vascular image are disclosed
wherein a single composite display simultaneously provides a first
view of a patient including an angiogram image and a second view
including an intravascular image rendered from information provided
by an imaging probe mounted on a distal end of a flexible elongate
member. A cursor, having a position derived from image information
provided by a radiopaque marker proximate the imaging probe, is
displayed within the angiogram image to correlate the position of
the imaging probe to a presently displayed intravascular image and
thus provide an easily discernable identification of a position
within a patient corresponding to a currently displayed
intravascular image. The resulting composite display simultaneously
provides: an intravascular image that includes information about a
vessel that is not available from an angiogram and a current
location within a vessel of a source of intravascular image data
from which the intravascular image is rendered.
Inventors: |
Huennekens; Richard Scott (San
Diego, CA), Fry; Stephen M. (El Dorado Hills, CA),
Walker; Blair D. (Mission Viejo, CA), Klingensmith; Jon
D. (El Dorado Hills, CA), Pool; Nancy Perry (El Dorado
Hills, CA), Burgess; Vincent J. (San Diego, CA), Kanz;
William R. (Sacramento, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
Volcano Corporation |
San Diego |
CA |
US |
|
|
Assignee: |
Volcano Corporation (San Diego,
CA)
|
Family
ID: |
36678153 |
Appl.
No.: |
13/865,803 |
Filed: |
April 18, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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60694014 |
Jun 24, 2005 |
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60642893 |
Jan 11, 2005 |
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Reissue of: |
11329609 |
Jan 11, 2006 |
7930014 |
Apr 19, 2011 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
8/543 (20130101); A61B 8/12 (20130101); A61B
6/487 (20130101); A61B 6/4494 (20130101); A61B
5/06 (20130101); A61B 6/5247 (20130101); A61B
8/463 (20130101); A61B 6/463 (20130101); A61B
6/12 (20130101); A61B 6/504 (20130101); A61B
5/0215 (20130101); A61B 6/4441 (20130101); A61B
8/4494 (20130101) |
Current International
Class: |
A61B
5/05 (20060101) |
Field of
Search: |
;600/407,424,425-427,437,453-455,462,466,467,473,476
;382/159,165,170,181 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2 449 080 |
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May 2005 |
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CA |
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HEI 5-084248 |
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Apr 1993 |
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JP |
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HEI 10-137238 |
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May 1998 |
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JP |
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WO 2004/075756 |
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Sep 2004 |
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WO |
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|
Primary Examiner: Kish; James
Attorney, Agent or Firm: Haynes and Boone, LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority of Huennekens et al. U.S.
provisional application Ser. No. 60/642,893 filed on Jan. 11, 2005,
entitled "Catheter Image Co- Registration," and Walker et al. U.S.
provisional application Ser. No. 60/694,014 filed on Jun. 24, 2005,
entitled "Three-Dimensional Co-Registration For Intravascular
Diagnosis and Therapy", the contents of both of the
above-identified provisional applications are expressly
incorporated herein by reference in their entirety including the
contents and teachings of any references contained therein.
Claims
What is claimed is:
1. A system for acquisition and co-registered display of
intravascular information, comprising: an imaging flexible elongate
member having a proximal end and a distal end; an imaging probe
located near the distal end of the flexible elongate member, and
configured to obtain information for generating an image of a
vessel; a radiopaque marker located near the imaging probe; a first
memory for storing angiogram image data; a second memory for
storing intravascular image data derived from information obtained
by the imaging probe; a third memory for storing radiopaque marker
image data, distinct from the angiogram image data, the radiopaque
marker image data being derived from information obtained from a
fluoroscopic imaging device; a display processor configured to
retrieve and combine data from the first memory, the second memory
and the third memory, and further configured to render a composite
image including: an enhanced radiological image derived from the
angiogram image data comprising a superimposition of at least a
portion of the angiogram data and the radiopaque marker image data
and providing a location of the radiopaque marker based upon an
actual location during active fluoroscopy and an estimated location
during inactive fluoroscopy, an intravascular image element
corresponding to the intravascular image data, wherein the enhanced
radiological image and the intravascular image element are
displayed proximate each other; and a cursor, displayed upon the
enhanced radiological image, indicative of a location of the
imaging probe while acquiring data for the intravascular image
element presently displayed on the composite image, said cursor
having a position that is based at least in part on third data
derived from the radiopaque marker image data stored in the third
memory; wherein the display processor is further configured to
calculate an error function based on a difference between the
estimated location of the radiopaque marker and the actual location
of the radiopaque marker and wherein the display processor further
configured to utilize the error function to correct the estimated
location of the radiopaque marker for the preceding period of
inactive fluoroscopy.
2. The system of claim 1 wherein the flexible elongate member is a
catheter.
3. The system of claim 1 wherein the imaging probe comprises an
ultrasound device.
4. The system of claim 3 wherein the ultrasound device is a
side-firing intravascular ultrasound transducer assembly.
5. The system of claim 4 wherein the side-firing intravascular
ultrasound transducer assembly comprises an array of transducer
elements.
6. The system of claim 5 wherein the array of transducer elements
are linearly arranged along a lengthwise axis of the flexible
elongate member.
7. The system of claim 5 wherein the array of transducer elements
are curvilinearly arranged about a lengthwise axis of the flexible
elongate member.
8. The system of claim 5 wherein the array of transducer elements
are circumferentially arranged about a lengthwise axis of the
flexible elongate member.
9. The system of claim 3 wherein the ultrasound device comprises a
Doppler transducer.
10. The system of claim 9 wherein the flexible elongate member
comprises a guidewire.
11. The system of claim 1 wherein the flexible elongate member is a
guidewire and the imaging probe comprises a pressure sensor.
12. The system of claim 1 wherein the radiopaque marker comprises a
cylindrical marker band.
13. The system of claim 1 wherein the radiopaque marker comprises
at least one partially complete cylindrical marker band.
14. The system of claim 13 wherein the radiopaque marker comprises
two semi-cylindrical marker bands.
15. The system of claim 14 wherein the two semi-cylindrical marker
bands are skewed in relation to one another along a lengthwise axis
of the flexible elongate member.
16. The system of claim 15 wherein the display processor further
comprises an orientation determination function for determining a
relative orientation of the imaging probe within the vessel based
upon at least a relative size and position of the two
semi-cylindrical marker bands in relation to one another.
17. The system of claim 1 wherein the third data is derived from
user-specified points.
18. The system of claim 1 wherein the third data is derived by
automated processes that determine a position of the radiopaque
marker within a field of view.
19. The system of claim 18 wherein the automated processes utilize
image pattern recognition to determine the position.
20. The system of claim 1 wherein the third data is derived from a
combination of manual user input and automated calculations.
21. The system of claim 20 wherein the automated calculations
include determination of a predicted path of the imaging probe.
22. The system of claim 1 wherein the display processor further
comprises a bookmark function enabling a user to designate
particular images of interest in a stored set of images containing
at least the intravascular image element.
23. The system of claim 1 wherein the enhanced radiological image
includes a calculated path of the imaging probe.
24. The system of claim 1 wherein the display processor further
comprises-a slider function associated with the cursor that enables
a user to reposition the cursor to a point of interest on the
enhanced radiological image through a user interface control, and
in response displays a particular instance of the intravascular
image element associated with the point of interest.
25. The system of claim 1, wherein the estimated location is based
at least in part on a calculated path of the imaging probe and
wherein the calculated path is updated based on the error function
that is calculated based on a difference between the estimated
location of the radiopaque marker and the actual location of the
radiopaque marker.
26. A method for acquiring and displaying intravascular information
in a system including an imaging flexible elongate member having a
proximal end and a distal end, an imaging probe located near the
distal end of the flexible elongate member, and configured to
obtain information for generating an image of a vessel, and a
radiopaque marker located near the imaging probe, the method
comprising the steps of: storing angiogram image data in a first
memory; storing intravascular image data derived from information
obtained by the imaging probe in a second memory; storing
radiopaque marker image data, distinct from the angiogram image
data, in a third memory, the radiopaque marker image data being
derived from information obtained from a fluoroscopic imaging
device; combining, by a display processor, data retrieved from the
first memory, the second memory and the third memory to render a
composite image including: an enhanced radiological image derived
from the angiogram image data comprising a superimposition of at
least a portion of the angiogram data and the radiopaque marker
data and providing a location of the radiopaque marker based upon
an actual location during active fluoroscopy and an estimated
location during inactive fluoroscopy, and an intravascular image
element corresponding to the intravascular image data, wherein the
enhanced radiological image and the intravascular image element are
displayed proximate each other; and displaying a cursor upon the
enhanced radiological image, indicative of a location of the
imaging probe while acquiring data for the intravascular image
element presently displayed on the composite image, said cursor
having a position that is based at least in part on third data
derived from the radiopaque marker image data previously stored in
the third memory; wherein the estimated location is based on a
calculated path of the imaging probe, and wherein an error function
is calculated based on a difference between the estimated location
of the radiopaque marker and the actual location of the radiopaque
marker when active fluoroscopy is resumed after inactive
fluoroscopy and wherein the error function is utilized to correct
the calculated path.
27. The method of claim 26 wherein the flexible elongate member is
a catheter.
28. The method of claim 26 wherein the imaging probe comprises an
ultrasound device.
29. The method of claim 28 wherein the ultrasound device comprises
a Doppler transducer.
30. The method of claim 26 wherein the flexible elongate member is
a guidewire and the imaging probe comprises a pressure sensor.
31. The method of claim 26 wherein the radiopaque marker comprises
two semi-cylindrical marker bands that are skewed in relation to
one another along a lengthwise axis of the flexible elongate member
and wherein the method comprises determining an orientation of the
imaging probe based upon at least a relative size and position of
the two semi-cylindrical marker bands in relation to one
another.
32. The method of claim 26 wherein the third data is derived from
user-specified points.
33. The method of claim 26 wherein the third data is derived by
automated processes that determine a position of the radiopaque
marker within a field of view.
34. The method of claim 26 wherein the third data is derived from a
combination of manual user input and automated calculations.
35. The method of claim 34 wherein the automated calculations
determine a predicted path of the imaging probe.
36. The method of claim 26 further comprising storing a
user-designated set of particular images of interest in a stored
set of images containing at least the intravascular image
element.
37. The method of claim 26 further comprising incorporating a
calculated path of the imaging probe within the enhanced
radiological image.
38. The method of claim 26 further comprising providing a slider
function associated with the cursor that enables a user to
reposition the cursor to a point of interest on the enhanced
radiological image through a user interface control, and in
response display a particular instance of the intravascular image
element associated with the point of interest.
39. The method of claim 26, wherein the calculated path is
calculated using a first multiplication coefficient if the imaging
probe is being pulled through the vessel and a second
multiplication coefficient if the imaging probe is being pushed
through the vessel.
40. A system for acquisition and co-registered display of
intravascular information, comprising: an imaging flexible elongate
member having a proximal end and a distal end; an imaging probe
located near the distal end of the flexible elongate member, and
configured to obtain information for generating an image of a
vessel; a radiopaque located near the imaging probe; a first memory
portion for storing angiogram image data; a second memory portion
for storing intravascular image data derived from information
obtained by the imaging probe; a third memory portion for storing
radiopaque marker image data, the radiopaque marker image data
being derived from information obtained from a fluoroscopic imaging
device; a display processor configured to retrieve and combine data
from the first memory portion, the second memory portion and the
third memory portion, and further configured to render a composite
image including: an enhanced radiological image derived from the
angiogram image data comprising a superimposition of at least a
portion of the angiogram data and the radiopaque marker image data
and providing a location of the radiopaque marker based upon an
actual location during active fluoroscopy and an estimated location
during inactive fluoroscopy, wherein an error function is
calculated based on a difference between the estimated location of
the radiopaque marker and the actual location of the radiopaque
marker when active fluoroscopy is resumed after inactive
fluoroscopy and wherein the error function is utilized to correct
the estimated location of the radiopaque marker for the preceding
period of inactive fluoroscopy, an intravascular image element
corresponding to the intravascular image data, wherein the enhanced
radiological image and the intravascular image element are
displayed proximate each other; and a cursor, displayed upon the
enhanced radiological image, indicative of a location of the
imaging probe while acquiring data for the intravascular image
element presently displayed on the composite image, said cursor
having a position that is based at least in part on third data
derived from the radiopaque marker image data stored in the third
memory portion.
41. The method of claim 40, wherein the calculated path is
calculated using a first multiplication coefficient if the imaging
probe is being pulled through the vessel and a second
multiplication coefficient if the imaging probe is being pushed
through the vessel.
42. The system of claim 40, wherein the imaging flexible elongate
member is a catheter.
43. The system of claim 40, wherein the imaging flexible elongate
member is a guidewire.
44. The system of claim 40, wherein the imaging probe includes an
ultrasound transducer.
45. The system of claim 40, wherein the imaging probe includes a
pressure sensor.
.Iadd.46. A system for acquisition and co-registered display of
intravascular information, comprising: a flexible elongate member
having a proximal end and a distal end; a diagnostic probe located
near the distal end of the flexible elongate member, and configured
to obtain information related to a vessel; a radiopaque marker
located near the diagnostic probe; a first memory for storing
angiogram image data; a second memory for storing intravascular
data derived from information obtained by the diagnostic probe; a
third memory for storing radiopaque marker image data, distinct
from the angiogram image data, the radiopaque marker image data
being derived from information obtained from a fluoroscopic imaging
device; a display processor configured to retrieve and combine data
from the first memory, the second memory and the third memory, and
further configured to render a composite image including: an
enhanced radiological image derived from the angiogram image data
comprising a superimposition of at least a portion of the angiogram
data and the radiopaque marker image data and providing a location
of the radiopaque marker based upon an actual location during
active fluoroscopy and an estimated location during inactive
fluoroscopy, an intravascular image element corresponding to the
intravascular data, wherein the enhanced radiological image and the
intravascular image element are displayed proximate each other; and
a cursor, displayed upon the enhanced radiological image,
indicative of a location of the diagnostic probe while acquiring
data for the intravascular image element presently displayed on the
composite image, said cursor having a position that is based at
least in part on third data derived from the radiopaque marker
image data stored in the third memory; wherein the display
processor is further configured to calculate an error function
based on a difference between the estimated location of the
radiopaque marker and the actual location of the radiopaque marker
and wherein the display processor further configured to utilize the
error function to correct the estimated location of the radiopaque
marker for the preceding period of inactive
fluoroscopy..Iaddend.
.Iadd.47. The system of claim 46 wherein the flexible elongate
member is a catheter..Iaddend.
.Iadd.48. The system of claim 46 wherein the diagnostic probe
comprises an ultrasound device..Iaddend.
.Iadd.49. The system of claim 48 wherein the ultrasound device is a
side-firing intravascular ultrasound transducer
assembly..Iaddend.
.Iadd.50. The system of claim 49 wherein the side-firing
intravascular ultrasound transducer assembly comprises an array of
transducer elements..Iaddend.
.Iadd.51. The system of claim 50 wherein the array of transducer
elements are linearly arranged along a lengthwise axis of the
flexible elongate member..Iaddend.
.Iadd.52. The system of claim 50 wherein the array of transducer
elements are curvilinearly arranged about a lengthwise axis of the
flexible elongate member..Iaddend.
.Iadd.53. The system of claim 50 wherein the array of transducer
elements are circumferentially arranged about a lengthwise axis of
the flexible elongate member..Iaddend.
.Iadd.54. The system of claim 48 wherein the ultrasound device
comprises a Doppler transducer..Iaddend.
.Iadd.55. The system of claim 54 wherein the flexible elongate
member comprises a guidewire..Iaddend.
.Iadd.56. The system of claim 46 wherein the flexible elongate
member is a guidewire and the diagnostic probe comprises a pressure
sensor..Iaddend.
.Iadd.57. The system of claim 46 wherein the radiopaque marker
comprises a cylindrical marker band..Iaddend.
.Iadd.58. The system of claim 46 wherein the radiopaque marker
comprises at least one partially complete cylindrical marker
band..Iaddend.
.Iadd.59. The system of claim 58 wherein the radiopaque marker
comprises two semi-cylindrical marker bands..Iaddend.
.Iadd.60. The system of claim 59 wherein the two semi-cylindrical
marker bands are skewed in relation to one another along a
lengthwise axis of the flexible elongate member..Iaddend.
.Iadd.61. The system of claim 60 wherein the display processor
further comprises an orientation determination function for
determining a relative orientation of the diagnostic probe within
the vessel based upon at least a relative size and position of the
two semi-cylindrical marker bands in relation to one
another..Iaddend.
.Iadd.62. The system of claim 46 wherein the third data is derived
from user-specified points..Iaddend.
.Iadd.63. The system of claim 46 wherein the third data is derived
by automated processes that determine a position of the radiopaque
marker within a field of view..Iaddend.
.Iadd.64. The system of claim 63 wherein the automated processes
utilize image pattern recognition to determine the
position..Iaddend.
.Iadd.65. The system of claim 46 wherein the third data is derived
from a combination of manual user input and automated
calculations..Iaddend.
.Iadd.66. The system of claim 65 wherein the automated calculations
include determination of a predicted path of the diagnostic
probe..Iaddend.
.Iadd.67. The system of claim 46 wherein the display processor
further comprises a bookmark function enabling a user to designate
particular images of interest in a stored set of images containing
at least the intravascular image element..Iaddend.
.Iadd.68. The system of claim 46 wherein the enhanced radiological
image includes a calculated path of the diagnostic
probe..Iaddend.
.Iadd.69. The system of claim 46 wherein the display processor
further comprises-a slider function associated with the cursor that
enables a user to reposition the cursor to a point of interest on
the enhanced radiological image through a user interface control,
and in response displays a particular instance of the intravascular
image element associated with the point of interest..Iaddend.
.Iadd.70. The system of claim 46, wherein the estimated location is
based at least in part on a calculated path of the diagnostic probe
and wherein the calculated path is updated based on the error
function that is calculated based on a difference between the
estimated location of the radiopaque marker and the actual location
of the radiopaque marker..Iaddend.
.Iadd.71. The system of claim 46, wherein the intravascular image
element is a cross-sectional intravascular ultrasound (IVUS)
image..Iaddend.
.Iadd.72. The system of claim 46, wherein the intravascular image
element is a graph representing the intravascular
data..Iaddend.
.Iadd.73. The system of claim 72, wherein the graph represents at
least one of blood pressure, blood flow velocity, shear stress, and
fractional flow reserve..Iaddend.
.Iadd.74. A method for acquiring and displaying intravascular
information in a system including a flexible elongate member having
a proximal end and a distal end, a diagnostic probe located near
the distal end of the flexible elongate member, and configured to
obtain information related to a vessel, and a radiopaque marker
located near the diagnostic probe, the method comprising the steps
of: storing angiogram image data in a first memory; storing
intravascular data derived from information obtained by the
diagnostic probe in a second memory; storing radiopaque marker
image data, distinct from the angiogram image data, in a third
memory, the radiopaque marker image data being derived from
information obtained from a fluoroscopic imaging device; combining,
by a display processor, data retrieved from the first memory, the
second memory and the third memory to render a composite image
including: an enhanced radiological image derived from the
angiogram image data comprising a superimposition of at least a
portion of the angiogram data and the radiopaque marker data and
providing a location of the radiopaque marker based upon an actual
location during active fluoroscopy and an estimated location during
inactive fluoroscopy, and an intravascular image element
corresponding to the intravascular data, wherein the enhanced
radiological image and the intravascular image element are
displayed proximate each other; and displaying a cursor upon the
enhanced radiological image, indicative of a location of the
diagnostic probe while acquiring data for the intravascular image
element presently displayed on the composite image, said cursor
having a position that is based at least in part on third data
derived from the radiopaque marker image data previously stored in
the third memory; wherein the estimated location is based on a
calculated path of the diagnostic probe, and wherein an error
function is calculated based on a difference between the estimated
location of the radiopaque marker and the actual location of the
radiopaque marker when active fluoroscopy is resumed after inactive
fluoroscopy and wherein the error function is utilized to correct
the calculated path..Iaddend.
.Iadd.75. The method of claim 74 wherein the flexible elongate
member is a catheter..Iaddend.
.Iadd.76. The method of claim 74 wherein the diagnostic probe
comprises an ultrasound device..Iaddend.
.Iadd.77. The method of claim 76 wherein the ultrasound device
comprises a Doppler transducer..Iaddend.
.Iadd.78. The method of claim 74 wherein the flexible elongate
member is a guidewire and the diagnostic probe comprises a pressure
sensor..Iaddend.
.Iadd.79. The method of claim 74 wherein the radiopaque marker
comprises two semi-cylindrical marker bands that are skewed in
relation to one another along a lengthwise axis of the flexible
elongate member and wherein the method comprises determining an
orientation of the diagnostic probe based upon at least a relative
size and position of the two semi-cylindrical marker bands in
relation to one another..Iaddend.
.Iadd.80. The method of claim 74 wherein the third data is derived
from user-specified points..Iaddend.
.Iadd.81. The method of claim 74 wherein the third data is derived
by automated processes that determine a position of the radiopaque
marker within a field of view..Iaddend.
.Iadd.82. The method of claim 74 wherein the third data is derived
from a combination of manual user input and automated
calculations..Iaddend.
.Iadd.83. The method of claim 82 wherein the automated calculations
determine a predicted path of the diagnostic probe..Iaddend.
.Iadd.84. The method of claim 74 further comprising storing a
user-designated set of particular images of interest in a stored
set of images containing at least the intravascular image
element..Iaddend.
.Iadd.85. The method of claim 74 further comprising incorporating a
calculated path of the diagnostic probe within the enhanced
radiological image..Iaddend.
.Iadd.86. The method of claim 74 further comprising providing a
slider function associated with the cursor that enables a user to
reposition the cursor to a point of interest on the enhanced
radiological image through a user interface control, and in
response display a particular instance of the intravascular image
element associated with the point of interest..Iaddend.
.Iadd.87. The method of claim 74, wherein the calculated path is
calculated using a first multiplication coefficient if the
diagnostic probe is being pulled through the vessel and a second
multiplication coefficient if the diagnostic probe is being pushed
through the vessel..Iaddend.
.Iadd.88. The method of claim 74, wherein the intravascular image
element is a cross-sectional intravascular ultrasound (IVUS)
image..Iaddend.
.Iadd.89. The method of claim 74, wherein the intravascular image
element is a graph representing the intravascular
data..Iaddend.
.Iadd.90. The method of claim 89, wherein the graph represents at
least one of blood pressure, blood flow velocity, shear stress, and
fractional flow reserve..Iaddend.
.Iadd.91. A system for acquisition and co-registered display of
intravascular information, comprising: a flexible elongate member
having a proximal end and a distal end; a diagnostic probe located
near the distal end of the flexible elongate member, and configured
to obtain information related to a vessel; a radiopaque marker
located near the diagnostic probe; a first memory portion for
storing angiogram image data; a second memory portion for storing
intravascular data derived from information obtained by the
diagnostic probe; a third memory portion for storing radiopaque
marker image data, the radiopaque marker image data being derived
from information obtained from a fluoroscopic imaging device; a
display processor that combines data retrieved from the first
memory portion, the second memory portion and the third memory
portion to render a composite image including: an enhanced
radiological image derived from the angiogram image data comprising
a superimposition of at least a portion of the angiogram data and
the radiopaque marker image data and providing a location of the
radiopaque marker based upon an actual location during active
fluoroscopy and an estimated location during inactive fluoroscopy,
wherein an error function is calculated based on a difference
between the estimated location of the radiopaque marker and the
actual location of the radiopaque marker when active fluoroscopy is
resumed after inactive fluoroscopy and wherein the error function
is utilized to correct the estimated location of the radiopaque
marker for the preceding period of inactive fluoroscopy, an
intravascular image element corresponding to the intravascular
data, wherein the enhanced radiological image and the intravascular
image element are displayed proximate each other; and a cursor,
displayed upon the enhanced radiological image, indicative of a
location of the diagnostic probe while acquiring data for the
intravascular image element presently displayed on the composite
image, said cursor having a position that is based at least in part
on third data derived from the radiopaque marker image data stored
in the third memory portion..Iaddend.
.Iadd.92. The system of claim 91, wherein the estimated location of
the radiopaque marker is calculated using a first multiplication
coefficient if the diagnostic probe is being pulled through the
vessel and a second multiplication coefficient if the diagnostic
probe is being pushed through the vessel..Iaddend.
.Iadd.93. The system of claim 91, wherein the diagnostic probe is a
catheter..Iaddend.
.Iadd.94. The system of claim 91, wherein the diagnostic probe is a
guidewire..Iaddend.
.Iadd.95. The system of claim 91, wherein the diagnostic probe
includes an ultrasound transducer..Iaddend.
.Iadd.96. The system of claim 91, wherein the diagnostic probe
includes a pressure sensor..Iaddend.
.Iadd.97. The system of claim 91, wherein the intravascular image
element is a cross-sectional intravascular ultrasound (IVUS)
image..Iaddend.
.Iadd.98. The system of claim 91, wherein the intravascular image
element is a graph representing the intravascular
data..Iaddend.
.Iadd.99. The system of claim 98, wherein the graph represents at
least one of blood pressure, blood flow velocity, shear stress, and
fractional flow reserve..Iaddend.
Description
AREA OF THE INVENTION
The present invention generally relates to imaging blood vessels.
More particularly, the present invention is directed to methods and
systems for generating composite displays relating a first image
rendered from a first type of data and a second image rendered from
a second type of data. A particular example of such composite
display comprises an angiogram displayed along-side an IVUS
image.
BACKGROUND OF THE INVENTION
In coronary arteries, vascular diseases including vessel lumen
narrowing, usually due to atherosclerotic plaque, can lead to
reduced blood flow to a heart muscle, angina (chest pain) and
myocardial infarction--a heart attack. A variety of interventional
treatments of cardiovascular disease are presently available to
identify and treat such narrowing of a vessel lumen. Examples of
such treatments include balloon angioplasty and/or deployment of
stents. Diagnostic imaging is utilized to identify the extent
and/or type of blockages within vessels prior to and/or during the
treatment of such blockages. Diagnostic imaging enables doctors to
ensure proper treatment of diseased vessels and verify the efficacy
of such treatment.
In general, two distinct manners exist for generating diagnostic
images for the identification and treatment of cardiovascular
disease within a vasculature. A first manner of diagnostic imaging
involves generating a radiological image of a stream flowing
through a blood vessel's lumen from outside the vessel lumen. The
purpose of generating an image of such flow is to identify
blockages within diseased blood vessels that restrict blood flow.
The extent of a vessel's lumen is traditionally imaged using
angiography, which involves rendering a two-dimensional view of one
or more vessels within a portion of a patient's vasculature through
which radiopaque contrast media has been injected. The
two-dimensional angiographic image can also be viewed real time by
fluoroscopy. During such procedures, the images are potentially
captured in various digital media, or in cine angiography (cine).
Cine angiography, though rendering higher quality images of blood
vessel lumens, exposes patients to high levels of ionizing
radiation.
Fluoroscopy, generally using substantially less intense radiation
than angiography, is used by physicians primarily to visually guide
diagnostic and therapeutic catheters or guidewires, including one
or more radiopaque markers, through vessels. The radiation
intensity during fluoroscopy is typically one-tenth the intensity
of radiation to which a patient is exposed during cine angiography.
Many catheters have radiopaque markers that are viewable on a
fluoroscope, thereby enabling a physician to track the
location/path of such catheters as they are inserted within and/or
withdrawn from patients. The platinum spring coil of guidewires
also serves as a radiopaque marker. The lower radiation intensity
of fluoroscopy allows a greater duration of use during a
diagnostic/treatment procedure. However, due to its greater time of
use, the total radiation exposure from fluoroscopy during an
interventional treatment procedure can greatly exceed the radiation
exposure during a typical cine angiography procedure. Thus, it is
incumbent upon a physician to minimize the duration of time that a
fluoroscope is used during a diagnostic and/or interventional
treatment procedure.
The first manner of imaging, described above, has a number of
drawbacks. For example, limited flow of contrast media near vessel
walls and extreme variations in vessel cross-sections can result in
incomplete filling of the vessel with a sufficient concentration of
contrast media. As a consequence, the diameters of vessel segments
can be misrepresented in an angiographic image. For example, a left
main coronary artery cross-section is often underestimated by
angiography. This can be problematic when attempting to judge the
significance of a blockage within the vessel or when choosing the
size of the treatment balloon or stent. An under-sized balloon or
stent will not provide as effective treatment as a properly sized
device. Furthermore, in angiography, a vessel's cross-section is
determined by a two-dimensional view which may not accurately
represent an actual extent of blood vessel narrowing.
Furthermore, to achieve an optimum treatment result, it is
important to correctly determine a true target diameter of a native
blood vessel--the diameter of a non-diseased blood vessel. However,
angiography is ineffective in determining the target diameter of a
vessel with disease along its entire length. For example, since
vessels tend to taper in diameter along their length, a uniformly
narrowed vessel may appear normal in an angiographic image.
Finally, angiography does not facilitate differentiating between
different types of tissue found in atherosclerotic plaque. For
example, in coronary arteries prone to producing a heart attack,
necrotic tissue is thought to be more prevalent than purely fibrous
tissue. Thus, while providing a good way to identify severe
blockages, angiography is not always the best diagnostic imaging
tool due to the incomplete nature of the angiographic image
data.
The second manner of intravascular imaging comprises imaging the
vessel itself using a catheter-mounted intravascular probe.
Intravascular imaging of blood vessels provides a variety of
information about the vessel including: the cross-section of the
lumen, the thickness of deposits on a vessel wall, the diameter of
the non-diseased portion of a vessel, the length of diseased
sections, and the makeup of the atherosclerotic plaque on the wall
of the vessel.
Several types of catheter systems have been designed to track
through a vasculature to image atherosclerotic plaque deposits on
vessel walls. These advanced imaging modalities include, but are
not limited to, intravascular ultrasound (IVUS) catheters, magnetic
resonance imaging (MRI) catheters and optical coherence tomography
(OCT) catheters. In addition, thermography catheters and
palpography catheters have also been demonstrated to generate
vessel image data via intravascular probes. Other catheter
modalities that have been proposed include infrared or
near-infrared imaging.
In operation, these intravascular catheter-mounted probes are moved
along a vessel in the region where imaging is desired. As the probe
passes through an area of interest, sets of image data are obtained
that, correspond to a series of "slices" or cross-sections of the
vessel, the lumen, and surrounding tissue. As noted above, the
catheters include radiopaque markers. Such markers are generally
positioned near a distal catheter tip. Therefore, the approximate
location of the imaging probe can be discerned by observing the
catheterization procedure on either a fluoroscope or angiographic
image. Typically imaging catheters are connected to a dedicated
console, including specialized signal processing hardware and
software, and display. The raw image data is received by the
console, processed to render an image including features of
concern, and rendered on the dedicated display device.
For example, IVUS images used to diagnose/treat vascular disease
generally comprise sets of cross-sectional image "slices" of a
vessel. A grayscale cross-sectional slice image is rendered, at
each of a set of positions along the vessel based upon the
intensity of ultrasound echoes received by an imaging probe.
Calcium or stent struts, which produce relatively strong echoes,
are seen as a lighter shade of gray. Blood or vessel laminae, which
produce weaker echoes, are seen as a darker shade of gray.
Atherosclerotic tissue is identified as being the portion of a
cross-sectional image between an internal elastic lamina (IEL) and
an external elastic lamina (EEL). The ability to see the vessel
lumen, and calculate its dimensions, allows the diameters and
cross-sectional area of the vessel to be determined more reliably
than the limited two-dimensional angiography. Because IVUS does not
rely upon dispersing a contrast agent, IVUS is especially useful in
generating images of the left main coronary artery as described
above. Furthermore, the ability to view the EEL, and calculate its
dimensions, allows an IVUS image to render a more reliable
determination than angiography, of the correct diameter and length
of the balloon or stent to use when restoring proper blood flow to
a blocked/diseased vessel. Advanced IVUS images have also been
described which perform tissue characterization and denote
different types of tissue with a color code. One such modality is
described in Vince, U.S. Pat. No. 6,200,268. Like IVUS, the other
catheters mentioned above display a series of cross-sectional
images from which additional information can be obtained.
Catheter-mounted probes, and in particular, IVUS probes can be
configured to render a variety of two and three-dimensional images.
In addition to the two-dimensional transverse cross-sectional
images discussed above, a longitudinal planar image can be
constructed from a plane which cuts through a "stack" of
cross-section "slices". In addition, three-dimensional
"fly-through" images can be constructed from information in a
series of cross-sectional slices of a vessel. Though these
three-dimensional images can be visually impressive, the two
dimensional angiography image remains the primary basis for
determining the location of a catheter in a vessel, and the
"schematic" reference through which the physician plans and carries
out a treatment procedure.
In creating the "stack" or "flythrough" images, some assumptions
are made by image data processing software in terms of the
orientation of each slice to the next. In many cases the compound
images, rendered from a series of transverse cross-sectional
slices, are rendered in the form of a straight vessel segment. In
reality, vessels can curve significantly. In segment visualizations
that render straight segments, spatial orientation of each
cross-sectional slice in relation to other slices is not measured.
In addition, the rotational orientation of a catheter-mounted probe
is generally not known due to twisting of the catheter as it passes
through a vessel. Therefore, the angular relation between adjacent
slices is not generally known. In many cases, these limitations do
not significantly effect treatment of a diseased vessel because the
typical treatment modalities (balloons, stents) are not
circumferentially specific. A balloon, for example, dilates a
vessel 360.degree. around a lumen.
In view of the advantages provided by the two above described
methods of imaging vessels, many catheter labs use both methods
simultaneously to diagnose and treat a patient. However, an
angiographic image provided on a different display monitor than a
corresponding IVUS image (or the other image rendered by a
catheter-mounted probe), presents challenges to a obtaining a
comprehensive understanding of a state of a diseased vessel. For
example, a physician identifies specific structures (e.g. feeder
vessels) in cross-sectional images in order to determine a location
on a vessel presented on an angiography display that needs to be
treated. Coordinating images rendered by two distinct display
devices can become cumbersome as the physician refers back and
forth between two different screens on two distinct display
devices. In addition, when a video loop of IVUS images is recorded,
to be played back later on a machine, a corresponding angiographic
image is not recorded in sync with it. Therefore, during playback,
the specific cross-section being viewed needs to be compared to the
vessel angiography, which is usually on a separate file.
A known visualization display simultaneously provides an angiogram,
an IVUS transverse plane view, and an IVUS longitudinal plane view.
A red dot is placed upon the angiogram corresponding to a currently
displayed IVUS transverse plane view. A blue line is placed upon
the angiogram corresponding to a currently displayed longitudinal
plane view. The reference dot and line are only as valuable as the
accuracy of the process that registers their positions on the
angiogram.
SUMMARY OF THE INVENTION
In order to provide a better overall view of vascular systems, in
accordance with the present invention, a system and method include
a single display simultaneously providing a first view of a patient
including an angiogram image and a second view including an
intravascular image rendered from information provided by an
imaging probe mounted on a distal end of a flexible elongate
member. A cursor, having a position derived from image information
provided by a radiopaque marker proximate the imaging probe, is
displayed within the angiogram image to correlate the position of
the imaging probe to a presently displayed intravascular image and
thus provide an easily discernable identification of a position
within a patient corresponding to a currently displayed
intravascular image. The resulting composite display simultaneously
provides: an intravascular image that includes information about a
vessel that is not available from an angiogram and a current
location within a vessel of a source of intravascular image data
from which the intravascular image is rendered.
BRIEF DESCRIPTION OF THE DRAWINGS
While the claims set forth the features of the present invention
with particularity, the invention, together with its objects and
advantages, may be best understood from the following detailed
description taken in conjunction with the accompanying drawing of
which:
FIG. 1 is a schematic illustration of a system for implementing
catheter image co-registration;
FIG. 2 depicts an illustrative angiogram image;
FIG. 3 depicts an illustrative fluoroscopic image of a radiopaque
marker mounted upon a catheter;
FIG. 4 depicts an illustrative enhanced radiological image
along-side a cross-sectional IVUS image;
FIG. 5 depicts an illustrative enhanced radiological image
along-side a cross-sectional IVUS image wherein the radiological
image further includes a calculated path within a vessel of
interest;
FIG. 6 depicts an illustrative enhanced radiological image
along-side a cross-sectional IVUS image wherein the radiological
image further includes a calculated path within a vessel of
interest with a marker positioned at a different location than the
view of FIG. 5;
FIG. 7 depicts an illustrative enhanced radiological image
along-side a cross-sectional IVUS image wherein the radiological
image further includes a calculated path within a vessel of
interest and a reference mark providing a point of
synchronization/calibration of a marker position;
FIG. 8 depicts an illustrative catheter distal end including a
single cylindrical radiopaque marker band;
FIG. 9a depicts a radiopaque marker band 900, suitable for use in
an exemplary embodiment, that partially encircles the catheter
shaft;
FIG. 9b depicts an imaging catheter having two of the radiopaque
marker bands of the type depicted in FIG. 9a wherein the two bands
are skewed by a quarter rotation along the axis of the
catheter;
FIG. 9c depicts the imaging catheter of 9b from a view that looks
directly on the full surface of the distal marker band 920;
FIG. 9d depicts the imaging catheter of 9c at a view wherein the
catheter is axially rotated 90 degrees from the position depicted
in FIG. 9c;
FIG. 9e depicts the imaging catheter at a different rotational
position from FIG. 9c and FIG. 9d;
FIG. 10 depicts an illustrative display for co-registration of
radiological and hemodynamic image information;
FIG. 11 is a flowchart summarizing a set of steps for rendering and
displaying a co-registered view during a data acquisition
procedure; and
FIG. 12 is a flowchart summarizing a set of steps for rendering and
displaying a co-registered view during playback of previously
acquired image data.
DETAILED DESCRIPTION OF THE DRAWINGS
In accordance with embodiments of the present invention, a method
and system are described by way of example herein below including
image data acquisition equipment and data/image processors that
generate views on a single display that simultaneously provides
positional information and intravascular images associated with a
imaging probe (e.g., an IVUS transducer probe) mounted upon a
flexible elongate member (e.g, a catheter, guidewire, etc.).
Turning initially to FIG. 1, an exemplary system is schematically
depicted for carrying out the present invention in the form of
co-registration of angiogram/fluoroscopy and intravascular
ultrasound images. The radiological and ultrasound image data
acquisition sub-systems are generally well known in the art. With
regard to the radiological image data, a patient 10 is positioned
upon an angiographic table 12. The angiographic table 12 is
arranged to provide sufficient space for the positioning of an
angiography/fluoroscopy unit c-arm 14 in an operative position in
relation to the patient 10 on the table 12. Radiological image data
acquired by the angiography/fluoroscopy c-arm 14 passes to an
angiography/fluoroscopy processor 18 via transmission cable 16. The
angiography/fluoroscopy processor 18 converts the received
radiological image data received via the cable 16 into
angiographic/fluoroscopic image data. The angiographic/fluoroscopic
("radiological") image data is initially stored within the
processor 18.
With regard to portions of the system associated with acquiring
ultrasound image data, an imaging catheter 20, and in particular an
IVUS catheter, is inserted within the patient 10 so that its distal
end, including a diagnostic probe 22 (in particular an IVUS probe),
is in the vicinity of a desired imaging location of a blood vessel.
While not specifically identified in FIG. 1, a radiopaque material
located near the probe 22 provides indicia of a current location of
the probe 22 in a radiological image. By way of example, the
diagnostic probe 22 generates ultrasound waves, receives ultrasound
echoes representative of a region proximate the diagnostic probe
22, and converts the ultrasound echoes to corresponding electrical
signals. The corresponding electrical signals are transmitted along
the length of the imaging catheter 20 to a proximal connector 24.
IVUS versions of the probe 22 come in a variety of configurations
including single and multiple transducer element arrangements. In
the case of multiple transducer element arrangements, an array of
transducers is potentially arranged: linearly along a lengthwise
axis of the imaging catheter 20, curvilinearly about the lengthwise
axis of the catheter 20, circumferentially around the lengthwise
axis, etc.
The proximal connector 24 of the catheter 20 is communicatively
coupled to a catheter image processor 26. The catheter image
processor 26 converts the signals received via the proximal
connector 24 into, for example, cross-sectional images of vessel
segments. Additionally, the catheter image processor 26 generates
longitudinal cross-sectional images corresponding to slices of a
blood vessel taken along the blood vessel's length. The IVUS image
data rendered by the catheter image processor 26 is initially
stored within the processor 26.
The type of diagnostic imaging data acquired by the diagnostic
probe 22 and processed by the catheter image processor 26 varies in
accordance with alternative embodiments of the invention. In
accordance with a particular alternative embodiment, the diagnostic
probe 22 is equipped with one or more sensors (e.g., Doppler and/or
pressure) for providing hemodynamic information (e.g., blood flow
velocity and pressure)--also referred to as functional flow
measurements. In such alternative embodiments functional flow
measurements are processed by the catheter image processor 26. It
is thus noted that the term "image" is intended to be broadly
interpreted to encompass a variety of ways of representing vascular
information including blood pressure, blood flow velocity/volume,
blood vessel cross-sectional composition, shear stress throughout
the blood, shear stress at the blood/blood vessel wall interface,
etc. In the case of acquiring hemodynamic data for particular
portions of a blood vessel, effective diagnosis relies upon the
ability to visualize a current location of the diagnostic probe 22
within a vasculature while simultaneously observing functional flow
metrics indicative of cardiovascular disease. Co-registration of
hemodynamic and radiological images facilitates precise treatment
of diseased vessels. Alternatively, instead of catheter mounted
sensors, the sensors can be mounted on a guidewire, for example a
guidewire with a diameter of 0.018'' or less. Thus, in accordance
with embodiments of the present invention, not only are a variety
of probe types used, but also a variety of flexible elongate
members to which such probes are mounted at a distal end (e.g.,
catheter, guidewire, etc.).
A co-registration processor 30 receives IVUS image data from the
catheter image processor 26 via line 32 and radiological image data
from the radiological image processor 18 via line 34.
Alternatively, the communications between the sensors and the
processors are carried out via wireless media. The co-registration
processor 30 renders a co-registration image including both
radiological and IVUS image frames derived from the received image
data. In accordance with an embodiment of the present invention,
indicia (e.g., a radiopaque marker artifact) are provided on the
radiological images of a location corresponding to simultaneously
displayed IVUS image data. The co-registration processor 30
initially buffers angiogram image data received via line 34 from
the radiological image processor 18 in a first portion 36 of image
data memory 40. Thereafter, during the course of a catheterization
procedure IVUS and radiopaque marker image data received via lines
32 and 34 is stored within a second portion 38 and a third portion
42, respectively, of the image data memory 40. The individually
rendered frames of stored image data are appropriately tagged
(e.g., time stamp, sequence number, etc.) to correlate IVUS image
frames and corresponding radiological (radiopaque marker) image
data frames. In an embodiment wherein hemodynamic data is acquired
rather than IVUS data, the hemodynamic data is stored within the
second portion 38.
In addition, additional markers can be placed on the surface of the
patient or within the vicinity of the patient within the field of
view of the angiogram/fluoroscope imaging device. The locations of
these markers are then used to position the radiopaque marker
artifact upon the angiographic image in an accurate location.
The co-registration processor 30 renders a co-registration image
from the data previously stored within the first portion 36, second
portion 38 and third portion 42 of the image data memory 40. By way
of example, a particular IVUS image frame/slice is selected from
the second portion 38. The co-registration processor 30 identifies
fluoroscopic image data within the third portion 42 corresponding
to the selected IVUS image data from the second portion 38.
Thereafter, the co-registration processor 30 superimposes the
fluoroscopic image data from the third portion 42 upon the
angiogram image frame retrieved from the first portion 36.
Thereafter, the co-registered radiological and IVUS image frames
are simultaneously displayed, along-side one another, upon a
graphical display device 50. The co-registered image data frames
driving the display device 50 are also stored upon a long-term
storage device 60 for later review in a session separate from a
procedure that acquired the radiological and IVUS image data stored
in the image data memory 40.
While not shown in FIG. 1, a pullback device is incorporated that
draws the catheter 20 from the patient at a controlled/measured
manner. Such devices are well known in the art. Incorporation of
such devices facilitates calculating a current position of the
probe 22 within a field of view at points in time when fluoroscopy
is not active.
Turning to FIG. 2, the angiography/fluoroscopy processor 18
captures an angiographic "roadmap" image 200 in a desired
projection (patient/vessel orientation) and magnification. By way
of example, the image 200 is initially captured by an angiography
procedure performed prior to tracking the IVUS catheter to the
region of interest within a patient's vasculature. Performing the
angiography procedure without the catheter 20 in the vessel
provides maximal contrast flow, better vessel filling and therefore
a better overall angiogram image. Thus, side branches such as side
branch 210 and other vasculature landmarks can be displayed and
seen clearly on the radiological image portion of a co-registered
image displayed upon the graphical display device 50.
Turning to FIG. 3, the catheter 20 is tracked to its starting
position (e.g., a position where an IVUS pullback procedure
begins). Typically the catheter 20 is tracked over a previously
advanced guidewire (not shown). Thereafter, a fluoroscopic image is
obtained. In the image, the catheter radiopaque marker 300 is
visualized, but the vessel lumen is not, due to the absence of
contrast flow. However, a set of locating markers present in both
the angiogram and fluoroscopy images enable proper positioning
(superimposing) of the marker image within the previously obtained
angiogram image. Other ways of properly positioning the radiopaque
marker image within the field of view of the angiogram image will
be known to those skilled in the art in view of the teachings
herein. Furthermore, the marker artifact can be automatically
adjusted (both size and position) on the superimposed image frames
to correspond to the approximate position of the transducers. The
result of overlaying/superimposing the radiopaque marker artifact
upon the angiogram image is depicted, by way of example in an
exemplary co-registration image depicted in FIG. 4.
Turning to FIG. 4 the exemplary co-registration display 401
(including the correlated radiological and IVUS images) depicts a
selected cross-sectional IVUS image 400 of a vessel. A radiological
image 410 is simultaneously displayed along-side the IVUS image 400
on the display 50. The radiological image 410 includes a marker
artifact 420, generated from radiological image data rendered by a
fluoroscope image frame, superimposed on an angiogram background
rendered from the first portion 36 of the memory 40. The
fluoroscope image frame corresponds to the current location of the
diagnostic probe 22 within a vessel under observation. Precise
matching of the field of view represented in both the angiogram and
fluoroscope images (i.e., precise projection and magnification of
the two images) allows identification of the current position of
the IVUS probe corresponding to the displayed IVUS image 400 in the
right pane of the co-registered images displayed in FIG. 4.
Alternatively, the composite radiological image 410 is obtained in
one step. In such case, the original roadmap angiogram image is
obtained with the catheter already in its starting position.
However, once obtained, the angiogram image is reused as the IVUS
probe is withdrawn from the vessel.
The system also takes heart motion into account when
generating/acquiring the radiological and IVUS image data. By way
of example, by acquiring the image data for both the angiogram
(background) and the radiopaque marker only during the peak R-wave
of the EKG, heart motion is much less a factor and good overlay
correlation exists between the angiogram and fluoroscope fields of
view. The peak R-wave is selected because it represents
end-diastole, during which the heart has the least amount of
motion, and thus, a more consistent condition from which to obtain
the radiological image data. The peak R-wave is also an easy point
in the EKG for the system to detect.
With continued reference to FIG. 4, in an exemplary embodiment when
the IVUS catheter 20 begins to image, the cross-sectional image 400
from the IVUS catheter is displayed in tandem with the enhanced
radiological image 410 including both the angiogram background and
the superimposed marker artifact 420. The enhanced radiological
image 410 and the cross-sectional IVUS image 400 are displayed
close to (e.g., along side) each other on the display 50, so that
the operator can concentrate on the information in the
cross-sectional image 400 while virtually simultaneously observing
the status of the enhanced radiological image 410.
The simultaneous display of both the composite/enhanced
radiological image and the cross-sectional image allows instant
awareness of both disease state of a vessel segment and the
location of the vessel segment within a patient. Such comprehensive
information is not readily discernable in a three dimensional
flythrough image or a stacked longitudinal image. Neither
flythrough nor stacked images alone allows for the simultaneous
appreciation of 1) all of the information in a cross-section, 2) a
feel for the shape of the vessel and 3) the location of the
cross-section along the length of the vessel. The above-described
"co-registration" of enhanced angiographic (including the marker
artifact) and intravascular cross-sectional images/information
delivers all three of these items in a presentation that is
straight forward to an operator with even average visual and
spatial abilities. The co-registration display is presented, by way
of example, either on an IVUS console display, or the
co-registration display is presented on one or more angiographic
monitors, either in the room where the procedure is occurring or in
a remote location. For example, one monitor over the table in the
procedure room allows the attending physician to view the
procedure, while at the same time a second consulting physician who
has not scrubbed for the case is also able to view the case via a
second monitor containing the co-registration display from a
separate control room. Control room viewing is also possible
without having to wear leaded covering.
With regard to the persistence of the background angiogram
("roadmap") image portion of the enhanced radiological image 410, a
single angiogram image is, by way of example, obtained/generated
and stored in the first portion 36 of the memory 40 for a given
procedure/patient position. If the field of view changes or the
patient's position changes, then an updated background angiogram
image is generated and stored in the first portion 36.
Alternatively, the background angiogram image is live or
continuously updated, for example, at each additional step in which
angiography is performed. The projection of the angiogram
roadmap/background image portion of the enhanced radiological image
410 is preferably in an orientation and magnification that best
displays the entire vessel to be viewed, taking into account the
foreshortening that is present in a tortuous/winding vessel.
Alternatively, two roadmap images (or even two enhanced
radiological images 410) can be used/displayed in place of the one
image 410. Such multiple views are provided in the context of
biplane angiography.
Establishing a position for the marker artifact within the field of
the enhanced radiological image, based at least in part upon a
radiopaque marker on the imaging catheter 20 is achievable in a
variety of ways. Examples, described further herein below include:
user-specified points (by clicking at a position near the marker to
establish a point); image pattern recognition (automatic
identification of a marker's unique signature within a field of
view); and combinations of manual and automated calculations of a
path.
Enhancing the background/roadmap angiogram image to render the
image 410 is achieved in a number of different ways. As mentioned
above, in an illustrative embodiment, the marker artifact 420
(derived from a fluoroscope image of a radiopaque marker near the
probe 22 mounted on the distal end of the catheter 20) is
superimposed upon/overlays the angiogram/roadmap background of the
enhanced radiological image 410. Because the live/marker artifact
portion of the image 410 requires that fluoroscopy be performed the
entire time of catheter movement (e.g. pullback), in an alternative
embodiment, the marker artifact is displayed on the image 410 only
during those periods when the fluoroscope is active. When the
fluoroscope is inactive, only the background angiogram is presented
on the enhanced image 410 of the display 50.
Turning to FIGS. 5 and 6, in embodiments of the invention, when the
fluoroscope is inactive, the co-registration processor 30
calculates an approximate location of the radiopaque marker based
upon its last registered position and other indicators of catheter
movement (e.g., pullback distance sensors/meters). The approximate
location is utilized in place of the radiopaque marker image to
render a marker artifact 520 on an enhanced radiological image 510
displayed along-side a corresponding IVUS cross-sectional image 500
within a display 501. By way of a particular illustrative example,
during periods in which a fluoroscope is inactive, the marker
artifact 520's position is calculated by software/hardware within
the co-registration processor 30 from sensor data indicative of a
current/changed location of the radiopaque marker within the
current image field provided by the current background angiogram
image. In an embodiment of the invention, a visual characteristic
(e.g., color, symbol, intensity, etc.) of the marker artifact 520
is used to distinguish when the fluoroscope is active/inactive and
thus indicate whether the marker artifact position is
actual/calculated. Furthermore, in more advanced systems, both the
displacement and angular orientation of the marker (and thus the
diagnostic probe 22) are determined to render accurate
approximations of the current position of the diagnostic probe 22
within a vessel as it acquires data for generating the image
500.
With continued reference to FIGS. 5 and 6, a calculated path
550/650 is determined by the co-registration processor 30 within
displays 501/601. A marker artifact 520/620 is placed on top of the
calculated path 550/650. The marker artifact 520/620 is
superimposed on the angiogram image at a location calculated from
non-visual position data (e.g., pull-back distance, spatial
position sensors, angular orientation sensors, etc.). For example,
if the initial location of a radiopaque marker within the enhanced
radiological image 510/610 is known and the catheter is pulled by
an automatic pullback system at a specific rate for a known amount
of time, the cursor can be placed by the system at a distance from
the initial location along the calculated path 550/650 that
represents the product of the pullback rate and the time period.
Furthermore, each subsequent time that a fluoroscope is activated
and an image of the radiopaque marker is acquired and presented to
the co-registration processor 30, an error between the actual
radiopaque marker location and a current calculated marker artifact
520/620 location is eliminated by replacing the calculated position
by a position calculated by the radiopaque marker image. The error
between the corrected position and the calculated location of the
marker artifact 520/620 is determined. In an exemplary embodiment,
the error/total travel distance ratio is used as a scaling factor
to recalculate and adjust all previously
calculated/rendered/presented marker artifact overlay positions on
the rendered/stored copies of the enhanced radiological image
510/610 for the entire preceding period in which the fluoroscope
has been inactive.
Similarly, a re-calculation can also update a shape of the
calculated path 550/560 curve. As seen in FIGS. 5 and 6, the
calculated path 550/650 is shown as a curve that matches the
tortuosity of a vessel through which the probe 22
passes--represented by a center line through the displayed vessel.
Alternatively, the catheter paths within vessels take a straighter
and shorter path than the centerline of a blood vessel when pulled
through such vessel. If, however, the catheter is being translated
by pushing, instead of pulling, the calculated path 550/650 more
closely matches the curvature of the vessel, or even exaggerates
the tortuosity of the vessel by taking a longer path. A
multiplication coefficient (e.g., 1.05 for pushing, 0.95 for
pulling) can be introduced when calculating a path based upon this
general observation of the path taken by a probe as it is
pushed/pulled through a vessel. The path can alternatively be
calculated from two different angiographic images taken at
different projections (planes). This allows a three dimensional
angiographic image, from which a true centerline can be
calculated.
In accordance with yet another embodiment, represented by the
co-registered IVUS image 700 and enhanced radiological image 710 in
a display 701 presented in FIG. 7, the operator creates a reference
mark 760 at one or more points on a calculated path 750. The
reference mark 760 serves a variety of potential uses. By way of
example, the reference mark 760 potentially serves as a benchmark
(location synchronization point) for updating position of a marker
artifact 720 within the enhanced radiological image 710. In the
embodiment represented by FIG. 7, the co-registration processor 30
waits for manual input of the reference mark 760 location
information prior to proceeding with calculations. The user creates
the reference mark 760 which coincides with a marker artifact 720
rendered from image data provided by a fluoroscope of a field of
view containing a radiopaque marker. The reference mark 760, which
potentially persists beyond its initial entry period, is
distinguished from the marker artifact 720 which follows the
current/estimated position of the probe 22. Furthermore, in an
exemplary embodiment the reference mark is used to highlight/mark
actual positions of the probe 22 (rendered by a fluoroscope image
of a radiopaque marker) as opposed to estimated points on a
calculated point (e.g. points on a path e.g., 550/560) from merely
calculated position estimates upon the paths 550/560. In yet other
embodiments, the reference mark 760 is used to highlight a
particular point of interest during a diagnostic/treatment
procedure. A bookmark is placed within a series of cross-sectional
images associated with the IVUS image 700 portion of the display
701. The bookmark allows quick access to a particular archived
image frame corresponding to the reference mark 760 in the display
701.
In accordance with embodiments of the present invention, a user
interface associated with the displayed images provided in FIGS.
4-7 includes a "slider" control that allows an operator to track
through a series of stored frames representing sequentially
acquired data along a traversed path within a vessel. The slider
control can be a set of arrows on a keyboard, a bar/cursor
displayed upon an enhanced radiological image that can be
manipulated by an operator, during playback, using a mouse or other
user interface device to traverse a vessel segment, etc. By way of
example, a display similar to FIG. 7 is rendered by the
co-registration processor 30 during playback of a previous data
acquisition session. A cursor similar to the reference mark 760 is
displayed during playback on the enhanced radiological image 710. A
user selects and drags the cursor along a path similar to the
calculated path 750. As the user drags and drops the cursor along
the path, the co-registration processor 30 acquires and presents
corresponding co-registered images. The user sequentially proceeds
through the stored images using, by way of example, arrow keys,
mouse buttons, etc.
It is noted that various catheter marking schemes are contemplated
that improve/optimize the co-registration processor 30's
calculations of a position of the marker artifact (representing a
position within a vessel corresponding to a currently displayed
IVUS cross-section image) when the fluoroscope is inactive. Turning
to FIG. 8, a single radiopaque marker band 800 is attached to the
catheter 820 near an IVUS probe. The radiopaque band 800 includes a
proximal edge 802 and a distal edge 804. The band 800 is
cylindrical, with the diameter at the proximal edge 802 equal to
the diameter at the distal edge 804. In addition, the band 800 has
a known length.
Upon connection of the proximal connector 24 of the catheter 20
into an outlet on the catheter image processor 26 (or an interposed
patient interface module which is communicatively connected to the
processor 26), the processor 26 receives identification information
from the catheter 20 via EPROM, RFID, optical reader or any other
appropriate method for identifying the catheter 20. In an
illustrative embodiment, the catheter length and diameter
dimensions (or dimension ratio) are included in the received
identification information. In addition, image field information
such as magnification and/or projection angle) from the
radiological image processor 18 is provided to the co-registration
processor 30. By identifying four points at the corners of an
approximate four-sided polygon of the marker band image, the
co-registration processor 30 automatically calculates
foreshortening of a vessel in an enhanced radiological image view
and the true length of a segment of a calculated path.
Turning briefly to FIGS. 9a-e, a catheter 920 carries two marker
bands having a known linear separation distance that facilitates
making the calculations described herein above with reference to
FIG. 8. FIG. 9a shows a radiopaque marker band 900, suitable for
use in an exemplary embodiment, that partially encircles the
catheter shaft; In the exemplary embodiment, the marker band 900
extends about 180.degree. (one half) of the perimeter of the
catheter shaft. The band is potentially made, for example, of 100%
Platinum, or 90% Platinum/10% Irridium, Tantalum, Gold or any other
radiopaque materials or combinations/amalgams thereof.
FIG. 9b shows an imaging catheter 20 having two of the radiopaque
marker bands 910 and 920 of the type depicted in FIG. 9a. The
proximal band 910 is skewed 90.degree. (a quarter of the
circumference of the catheter 20) in relation to the distal band
920. In this embodiment, the bands 910/920 are shown equally spaced
on opposite sides of the diagnostic probe 22 . This catheter 20
also has a guidewire lumen 930 for passing a guidewire, for example
a 0.014'' guidewire. The guidewire exits out the distal guidewire
port. The proximal end of the guidewire can exit a proximal port
either within the blood vessel (short lumen rapid exchange
catheter), within a guiding catheter (long lumen rapid exchange
catheter) or outside of the patient (over-the-wire catheter).
FIG. 9c shows the imaging catheter 20 from a view that looks
directly on the full surface of the distal marker band 920. Exactly
one half of the proximal marker band 910, skewed by 90 degrees, is
seen. An angiography image of the two marker bands, when viewed as
shown in FIG. 9c reveals band 920 having a thickness that is twice
the thickness of the image of the band 910. Furthermore, an image
length "L" of the marker bands 910/920 depends on angular position
of the portion of the catheter 20 in the image containing the bands
910/920. In a perfect side view, the length L is equal to the
actual length of the marker band. Offset O is equal to the
difference between the thickness of band 920 and the thickness of
band 910.
In FIG. 9d an image is taken at a view wherein the catheter 20 is
axially rotated 90 degrees from the position depicted in FIG. 9c.
The thickness of band 920 is half the thickness of band 910. Also,
the position of the relative positions of the bands 910/920 in
relation to the axis of the catheter 20 is used to determine the
actual angular orientation of the catheter 20 since the offset
alone is not enough to establish a current rotational position of
the catheter 20.
FIG. 9e is an image of the catheter 20 and bands 910/910 at a
different rotational position from FIG. 9c and FIG. 9d. The
orientation of the catheter can be determined by comparing the
relative thicknesses (e.g., the offset, a ratio) of the thickness
of images of the bands 910 and 920.
Other controls associated with the co-registration processor 30
facilitate performing a variety of additional tasks. For example,
during a catheter pullback, a commenting functionality incorporated
into the processor 30 enables a user to select a "bookmark" button.
In response, the co-registration processor 30 attaches a
note/comment to a specific cross-section and/or location along a
calculated path on an enhanced radiological image.
As mentioned above, an alternative version of co-registration image
scheme incorporates biplane angiography instead of standard, single
view angiography images. In biplane angiography, two radiological
projections are simultaneously presented to a user--e.g., two views
skewed by 90 degrees on a common axis of rotation. In such systems,
two enhanced radiological images are presented along-side a
cross-sectional image. During an inactive fluoroscopy period, when
marker artifact (cursor) position is determined by calculations in
relation to a known pullback rate, two cursor positions are
determined--one on each of the two enhanced radiological images. It
is expected that at certain periods during which fluoroscopy is
inactive, the foreshortening of the vessel seen on one biplane
image is less than the other. Depending on the 3-dimensional vessel
tortuosity, it is expected that the opposite biplane image would
have less foreshortening at other periods where a marker artifact
is based upon calculations rather than actual fluoroscope images.
The errors are calculated independently in the two different
biplane images, and corresponding scaling factors are generated for
the correction. As previously mentioned, a derived 3-dimensional
road-map is created based on information of the two images from
different planes. In this case, the two different planes are the
90.degree. biplane images Locating a marker artifact on a derived
3-D image is calculated from locations of marker artifacts one each
of two orthogonal biplane images.
All of the descriptions hereinabove associated with illustrative
embodiments using an IVUS catheter are applicable to a variety of
alternative types of imaging catheters. Similarly, an enhanced
radiological image can be combined with a longitudinal stack
instead of a cross sectional slice--in fact, the enhanced
radiological, transverse cross-sectional, and longitudinal
cross-sectional images can be displayed together. In yet other
embodiments, the enhanced radiological image is presented
along-side an IVUS image including both grayscale and color image
artifacts that characterizing tissue and deposits within a vessel.
Additionally, the longitudinal IVUS grayscale image and/or the
color (Virtual Histology) image are overlaid on the 2-D
angiographic image or derived 3-D image.
The above-described examples of co-registration have primarily
addressed IVUS examples. However, as mentioned above,
co-registration is alternatively incorporated into functional flow
measurement systems that provide hemodynamic image information such
as blood flow velocity and pressure. Turning briefly to FIG. 10, an
exemplary co-registration display 1001 rendered by the
co-registration processor 30 includes an enhanced radiological
image 1010 displayed along-side functional flow measurement values
presented in a graph 1000. In FIG. 10 functional flow reserve (FFR)
is depicted in the graph 1000 as a function of displacement along a
length of a blood vessel. The enhanced radiological image 1010
comprises a marker artifact 1020 superimposed upon an angiogram
image. The marker artifact 1020 indicates the point at which the
presently displayed functional flow measurements are being
presented based upon measurements previously acquired by
sensors/transducers on the probe 22 mounted at the distal end of a
flexible elongate member such as a guidewire or the catheter 20. In
yet another illustrative embodiment, the co-registration image
further includes an IVUS cross-sectional image (not depicted)
corresponding to the vessel segment indicated by the marker
artifact 1020 on the enhanced radiological image 1010.
The display also includes a variety of additional text information
associated with the section of the vessel identified by the marker
artifact 1020. Vessel dimensions 1030 specify an approximate
diameter and lumen area of a particular cross section indicated by
the marker artifact 1020's current position on the enhanced
radiological image 1010. Additionally, IVUS information 1040
specify a plaque burden percentage and a total plaque area for a
current cross-sectional slice indicated by the marker artifact
1020. An FFR information 1050 specifies a current FFR value
associated with the current location of the marker artifact 1020.
It is noted that the marker artifact 1020 approximates the location
of a probe (e.g., probe 22) at the time data was acquired to render
the presently displayed data values. In accordance with an
exemplary embodiment of the present invention, the location of the
marker artifact 1020 is derived from image data provided by a
radiopaque element/marker located near a probe mounted upon a
flexible elongate member such as probe 22 mounted on a guidewire or
catheter 20.
By way of example, the marker artifact 1020 operates as a slider
control that enables a user to sequentially traverse a set of
stored data records containing information of the type displayed in
FIG. 10. Furthermore, in the particular example, an FFR value
associated with a particular location designated by the marker
artifact 1020 is displayed near the marker artifact 1020. Also, a
second slider 1060 is also provided that is linked to the position
of marker artifact 1020 and thus moves in synchronism with the
marker artifact 1020. Moving either the slider 1060 or the marker
artifact 1020 causes movement of the other.
Other types of interventional ultrasound imaging, such as
Intracardiac Echocardiography are also envisioned that utilize this
co-registration system. For example a steerable catheter with a
linear, curvilinear, circumferential or other ultrasonic array at
the distal end is placed into or in proximity to the chambers of
the heart, and its location is incorporated into an enhanced
ultrasound image.
Having described exemplary systems embodying the present invention,
attention is directed to FIG. 11 that summarizes a set of exemplary
steps associated with the operation of the above-described systems.
Initially, during step 1100 an angiogram image is generated and
stored within the first portion 36 of image data memory 40. A
single angiogram image can be used to support co-registered display
of multiple acquired data sets from the probe 22 as the probe 22
passes within a length of a blood vessel. A visual artifact (e.g.,
marker artifact 420) having a position determined at least in part
upon a radiopaque marker positioned near the probe 22 on the
imaging catheter 20, is superimposed on the angiogram image. As the
probe 22 passes within the blood vessel the visual artifact
progresses along the angiogram image of the blood vessel thereby
providing an approximate location of the probe 22 associated with
currently displayed data rendered according to information provided
by the probe 22.
Thereafter, during step 1105 an initial calculated path (e.g., path
550) is generated by the co-registration processor 30. This
estimation of the path can be generated according to any of a
variety of methods including: automated two-dimensional and
three-dimensional path calculations; manual path specification; and
user assisted automated path calculations (a combination of
automated path calculation with user-specified over-rides). The
calculated path is superimposed upon the angiogram image generated
during step 1100 and represents the projected path of the probe 22
when pullback is commenced of the probe 22.
In an exemplary embodiment, the operation of the co-registration
system is determined by whether the fluoroscope has been activated
(providing a live image of a radiopaque marker mounted proximate
the probe 22). If the fluoroscope is active, then control passes to
step 1115 wherein a fluoroscope image (see, e.g., FIG. 3) of the
radiopaque marker is acquired, timestamped and stored. Thereafter,
at step 1120 image data associated with the probe 22 is acquired,
timestamped and stored. In the illustrative example, the image data
comprises an IVUS image generated by an ultrasound transducer probe
mounted upon the imaging catheter 20.
At step 1125 the co-registration processor 30 superimposes/overlays
a marker artifact on the previously stored angiogram image to
render the aforementioned enhanced radiological image. The marker
artifact derives is position, at least in part, from the previously
acquired and stored radiopaque marker position data. The enhanced
radiological (e.g., angiogram) image is thereafter stored with the
timestamp associated with the radiopaque marker position data
during step 1130.
Thereafter, at step 1135 the co-registration processor 30 renders
and simultaneously presents on a display/monitor the previously
generated enhanced angiogram image and a corresponding probe (IVUS)
image. The enhanced angiogram image and the corresponding probe
image are displayed along-side one another on the display/monitor.
Selection of a corresponding image is based upon a timestamp
associated with the selected IVUS probe image. The respective
timestamps of the radiological and probe components of the
co-registered display need not be identical. In an embodiment of
the invention a closest match criterion is applied to the selection
process. Control then returns to step 1110 for another iteration of
the co-registration imaging process.
Alternatively, if the fluoroscope is inactive during a period
wherein a pullback mechanism is drawing the probe 22 through a
segment of a vessel of interest, then control passes from step 1110
to step 1150. At 1150 the co-registration processor 30
acquires/registers a pullback rate for the pullback mechanism. At
step 1155 image data associated with the probe 22 is acquired,
timestamped and stored. In the illustrative example, the image data
comprises an IVUS image generated by an ultrasound transducer probe
mounted upon the imaging catheter 20. During step 1160 the
processor 30 determines a time that has elapsed since the previous
calculation of the artifact marker position. In cases where the
elapsed time is a constant, this step need not be repeated once the
elapsed time constant has been determined. During step 1165 the
co-registration processor 30 generates an estimate of a present
position of the probe 22 and a corresponding marker artifact
position on the enhanced radiological image. By way of example, the
pullback rate and the elapsed time between a previous marker
artifact position determination and the present position
determination are used to generate a present position estimate for
the marker artifact.
Thereafter, during step 1170 the co-registration processor 30
superimposes/overlays a marker artifact on the angiogram at the new
calculated position based upon the calculated path and the distance
calculation rendered during step 1165. During step 1175 the
enhanced radiological (e.g., angiogram) image is stored with the
timestamp associated with the calculated marker artifact position
data. Thereafter, at step 1180 the resulting enhanced radiological
image is utilized to render and present a co-registered display
including both the enhanced angiogram image and a corresponding
(based upon timestamp) previously stored probe image. Control
thereafter returns to step 1110.
The above-described steps are associated with providing a
co-registered display as an intravascular probe mounted upon a
flexible elongate member (e.g., a catheter, guidewire, etc.)
progresses along a length of blood vessel. Co-registered displays
are also rendered in a playback mode. Turning to FIG. 12, during
step 1200 the co-registration processor 30 initially displays an
enhanced radiological image including, for example, an angiogram
image, a calculated path, and a cursor/slider mark positioned on
the calculated path indicating a location associated with a
presently provided image derived from data acquired by the probe 22
at the indicated location on the enhanced radiological image.
During step 1205 a user positions the cursor/slider mark on the
calculated path. Such repositioning can occur in any of a number of
ways. By way of example, the user drags and drops the cursor/slider
using a mouse. Alternatively, a keyboard input can advance/backup
the cursor/slider through a series of previously
designated/bookmarked points along the calculated path displayed
within the enhanced angiogram image provided during step 1200. Yet
other keys can be used to advance the cursor/slider on a
record-by-record basis through a set of stored records associated
with the progression of the probe 22 along the calculated path.
Still other modes of selecting a position of interest on the
calculated path and its associated probe 22 (e.g., IVUS) image will
be contemplated by those skilled in the art in view of the
description provided herein.
During step 1210 in response to a particular position/timestamp
associated with a current position of the cursor/slider on the
enhanced radiological image, the co-registration processor 30
accesses a corresponding record within the set of records derived
from the data provided by the probe 22. By way of example, such
data sets include cross-sectional IVUS images or alternatively FFR
values at specified positions along a blood vessel. Thereafter,
during step 1215 a co-registered view is presented wherein the
enhanced radiological image, including the calculated path and
cursor/slider (derived at least partially from positional
information provided by a radiopaque marker during data
acquisition), is displayed along-side an image (e.g., an IVUS
cross-section) derived from data provided by the probe 22 at a
position indicated by the current cursor/slider position within the
enhanced radiological image. The steps depicted in FIG. 12 are
repeated in response to a detected change in the position of the
cursor/slider to update the display to show the new position of the
cursor/slider and the corresponding image (e.g. cross-sectional
IVUS image) derived from data provided by the probe 22 at the
designated cursor/slider position.
The structures, techniques, and benefits discussed above are merely
exemplary embodiments of the invention. In view of the many
possible embodiments to which the principles of this invention may
be applied, it should be recognized that the embodiments described
herein with respect to the drawing figures are meant to be
illustrative only and should not be taken as limiting the scope of
invention. For example, while separate processors are shown to
carry out particular aspects of the invention, in alternative
embodiments the functionality of the multiple processors can be
incorporated into a single processor or even distributed among even
more processors. Therefore, the invention as described herein
contemplates all such embodiments as may come within the scope of
the following claims and equivalents thereof.
* * * * *
References