U.S. patent application number 11/312023 was filed with the patent office on 2007-03-01 for clinical feedback of ablation efficacy during ablation procedure.
This patent application is currently assigned to General Electric Company. Invention is credited to Brenda L. Donaldson.
Application Number | 20070049827 11/312023 |
Document ID | / |
Family ID | 37440973 |
Filed Date | 2007-03-01 |
United States Patent
Application |
20070049827 |
Kind Code |
A1 |
Donaldson; Brenda L. |
March 1, 2007 |
Clinical feedback of ablation efficacy during ablation
procedure
Abstract
There is provided a method and system for combining physiology
information with ultrasound based anatomic structures during an
ablation procedure. The embodiments relate to methods and systems
that construct a 2D or 3D representation of an anatomical structure
based on ultrasound data and superimpose thereon graphical
information representative of physiologic characteristics of the
anatomic structure in real-time or near real-time during an
ablation procedure.
Inventors: |
Donaldson; Brenda L.;
(Harrison Township, MI) |
Correspondence
Address: |
GE MEDICAL SYSTEM;C/O FOLEY & LARDNER LLP
777 EAST WISCONSIN AVENUE
MILWAUKEE
WI
53202-5306
US
|
Assignee: |
General Electric Company
|
Family ID: |
37440973 |
Appl. No.: |
11/312023 |
Filed: |
December 20, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11204711 |
Aug 16, 2005 |
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11312023 |
Dec 20, 2005 |
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Current U.S.
Class: |
600/443 ;
600/437; 600/439 |
Current CPC
Class: |
A61B 8/543 20130101;
A61B 8/483 20130101; A61B 5/0215 20130101; A61B 8/12 20130101; A61B
8/467 20130101; A61B 5/06 20130101; A61B 8/4245 20130101; A61B
8/469 20130101; A61B 2090/378 20160201; A61B 8/0883 20130101; A61B
8/0833 20130101; A61B 8/461 20130101; A61B 8/5238 20130101; A61B
8/14 20130101; A61B 5/283 20210101 |
Class at
Publication: |
600/443 ;
600/437; 600/439 |
International
Class: |
A61B 8/00 20060101
A61B008/00 |
Claims
1. A method of obtaining real-time or near real-time feedback as to
the efficacy of an ablation procedure on a subject of interest at
an ablation site, the method comprising the steps of: receiving
signals from an ultrasound probe located proximate the ablation
site and, based thereon producing ultrasound data representative of
a scan plane including the ablation site; generating an ultrasound
image based on the ultrasound data, the ultrasound image being
representative of an anatomical structure of a portion of the
ablation site contained in the scan plane; receiving physiology
signals from a physiology catheter located proximate the ablation
site and, based thereon producing physiology data representative of
physiologic activity of the portion of the ablation site contained
in the scan plane; forming a display image combining the ultrasound
image and physiology data and saving the image in a
electrophysiology recording system; detecting a change in the
subject Of interest proximate the ablation site; receiving, in
real-time or near real-time, signals from the ultrasound probe
located proximate the ablation site and, based thereon producing a
second ultrasound data representative of the scan plane including
the ablation site; generating, in real-time or near real-time, a
second ultrasound image based on the second ultrasound data, the
second ultrasound image being representative of the change in the
anatomical structure of a portion of the ablation site contained in
the scan plane; receiving, in real-time or near real-time,
physiology signals from the physiology catheter located proximate
the ablation site and, based thereon producing a second physiology
data representative of physiologic activity of the portion of the
ablation site contained in the scan plane; and forming, in
real-time or near real-time, a second display image combining the
second ultrasound image and second physiology data and saving the
second image in the electrophysiology recording system.
2. The method of claim 1, further comprising the steps of comparing
the first and second display images of the combined ultrasound
image and physiology data, wherein the efficacy of the ablation
procedure can be determined.
3. The method of claim 1, wherein detecting a change in the subject
of interest includes determining tissue characterization as being
one of conducting and non-conducting tissue.
4. The method of claim 1, wherein the display image includes
physiology data mapped onto an anatomical structure contained in
and defined by the ultrasound image.
5. The method of claim 1, wherein the ultrasound signal is received
from an ultrasound probe constituting at least one of an
intravascular ultrasound (IVUS) catheter, an echocardiography (ICE)
catheter, a transesophageal probe, an interventional probe and a
surface probe.
6. The method of claim 1, wherein the physiology data is received
from a physiology catheter constituting at least one of an
electrophysiology (EP) catheter and a hemodynamic (HD)
catheter.
7. The method of claim 1, further comprising receiving ECG signals
from ECG leads provided on the surface of the subject; deriving
cardiac cycle data based on one of the ECG signals and intracardiac
signals obtained from an electrophysiology catheter; and utilizing
the cardiac cycle data to synchronize the ultrasound images and
physiology data.
8. The method of claim 1, further comprising tracking a position of
an ultrasound probe and a physiology catheter, and generating
tracking information denoting positions of the ultrasound probe and
physiology catheter with respect to a common reference coordinate
system.
9. The method of claim 1, further comprising registering the
ultrasound image and physiology data within a common coordinate
reference system.
10. The method of claim 1, further comprising receiving ECG signals
from ECG leads placed on a subject, and generating timing
information from the ECG signals, the timing information being
representative of cyclical points in a subject's cardiac cycle.
11. The method of claim 1, further comprising generating and
displaying new ultrasound images at a frame rate of at least seven
frames per second.
12. The method of claim 1, further comprising forming a volumetric
ultrasound data set for a series of the scan planes, the display
image constituting a three-dimensional representation of the
ultrasound image and physiology data.
13. The method of claim 1, wherein the ultrasound image and
physiology data combined in the display image are obtained at a
common time in a cyclical motion of the region of interest.
14. The method of claim 1, wherein the ultrasound image is
representative of least one of B-mode, power Doppler, color flow,
M-mode, anatomic M-mode, ARFI mode, strain and strain rate
information.
15. The method of claim 1, wherein the physiology data is denoted
in the display image as at least one of gray scale information and
color information combined with the ultrasound image.
16. The method of claim 1, further comprising accessing a lookup
table based on the ultrasound image data and physiology data to
define pixel values of the display image, the lookup table
identifying pixel values to be used in the display image based on
the ultrasound image data and physiology data.
17. The method of claim 1, further comprising presenting, in the
display image, the ultrasound image data as gray scale information
and the physiology data as color information.
18. The method of claim 1, further comprising providing a user
interface the permits an operator to designate a point on the
subject of interest, in response to the user designation,
presenting a graph of physiology data over a period of time
associated with a designated point on the region of interest.
19. A method of obtaining real-time or near real-time feedback as
to the efficacy of an ablation procedure on a subject of interest
at an ablation site, the method comprising the steps of: receiving
signals from an ultrasound probe located proximate the ablation
site and, based thereon producing ultrasound data representative of
a scan plane including the ablation site; generating an ultrasound
image based on the ultrasound data, the ultrasound image being
representative of an anatomical structure of a portion of the
ablation site contained in the scan plane; receiving physiology
signals from a physiology catheter located proximate the ablation
site and, based thereon producing physiology data representative of
physiologic activity of the portion of the ablation site contained
in the scan plane; forming a display image combining the ultrasound
image and physiology data and saving the image in a
electrophysiology recording system; detecting a change in the
subject of interest proximate the ablation site; receiving, in
real-time or near real-time, signals from the ultrasound probe
located proximate the ablation site and, based thereon producing a
second ultrasound data representative of the scan plane including
the ablation site; generating, in real-time or near real-time, a
second ultrasound image based on the second ultrasound data, the
second ultrasound image being representative of the change in the
anatomical structure of a portion of the ablation site contained in
the scan plane; receiving, in real-time or near real-time,
physiology signals from the physiology catheter located proximate
the ablation site and, based thereon producing a second physiology
data representative of physiologic activity of the portion of the
ablation site contained in the scan plane; forming, in real-time or
near real-time, a second display image combining the second
ultrasound image and second physiology data and saving the second
image in the electrophysiology recording system; and tracking a
position of an ultrasound probe and a physiology catheter, and
generating tracking information denoting positions of the
ultrasound probe and physiology catheter with respect to a common
reference coordinate system and registering the ultrasound image
and physiology data within a common coordinate reference
system.
20. The method of claim 19, further comprising the steps of
comparing the first and second display images of the combined
ultrasound image and physiology data, wherein the efficacy of the
ablation procedure can be determined.
21. The method of claim 19, wherein detecting a change in the
subject of interest includes determining tissue characterization as
being one of conducting and non-conducting tissue.
22. The method of claim 19, wherein the display image includes
physiology data mapped onto an anatomical structure contained in
and defined by the ultrasound image.
23. The method of claim 19, wherein the ultrasound signal is
received from-an ultrasound probe constituting at least one of an
intravascular ultrasound (IVUS) catheter, an echocardiography (ICE)
catheter, a transesophageal probe, an interventional probe and a
surface probe.
24. The method of claim 19, wherein the physiology data is received
from a physiology catheter constituting at least one of an
electrophysiology (EP) catheter and a hemodynamic (HD)
catheter.
25. The method of claim 19, further comprising receiving ECG
signals from ECG leads provided on the surface of the subject;
deriving cardiac cycle data based on one of the ECG signals and
intracardiac signals obtained from an electrophysiology catheter;
and utilizing the cardiac cycle data to synchronize the ultrasound
images and physiology data.
26. The method of claim 19, further comprising receiving ECG
signals from ECG leads placed on a subject, and generating timing
information from the ECG signals, the timing information being
representative of cyclical points in a subject's cardiac cycle.
27. The method of claim 19, further comprising generating and
displaying new ultrasound images at a frame rate of at least seven
frames per second.
28. The method of claim 19, further comprising forming a volumetric
ultrasound data set for a series of the scan planes, the display
image constituting a three-dimensional representation of the
ultrasound image and physiology data.
29. The method of claim 19, wherein the ultrasound image and
physiology data combined in the display image are obtained at a
common time in a cyclical motion of the region of interest.
30. The method of claim 19, wherein the ultrasound image is
representative of least one of B-mode, power Doppler, color flow,
M-mode, anatomic M-mode, ARFI mode, strain and strain rate
information.
31. The method of claim 19, wherein the physiology data is denoted
in the display image as at least one of gray scale information and
color information combined with the ultrasound image.
32. The method of claim 19, further comprising accessing a lookup
table based on the ultrasound image data and physiology data to
define pixel values of the display image, the lookup table
identifying pixel values to be used in the display image based on
the ultrasound image data and physiology data.
33. The method of claim 19, further comprising presenting, in the
display image, the ultrasound image data as gray scale information
and the physiology data as color information.
34. The method of claim 19, further comprising providing a user
interface the permits an operator to designate a point on the
subject of interest, in response to the user designation,
presenting a graph of physiology data over a period of time
associated with a designated point on the region of interest.
35. A method of obtaining real-time or neat real-time feedback as
to the efficacy of an ablation procedure on a subject of interest
at an ablation site, the method comprising the steps of: receiving
signals from an ultrasound probe located proximate the ablation
site and, based thereon producing ultrasound data representative of
a scan plane including the ablation site; generating an ultrasound
image based on the ultrasound data, the ultrasound image being
representative of an anatomical structure of a portion of the
ablation site contained in the scan plane; receiving physiology
signals from a physiology catheter located proximate the ablation
site and, based thereon producing physiology data representative of
physiologic activity of the portion of the ablation site contained
in the scan plane; forming a display image combining the ultrasound
image and physiology data and saving the image in a
electrophysiology recording system; detecting a change in the
subject of interest proximate the ablation site; receiving, in
real-time or near real-time, signals from the ultrasound probe
located proximate the ablation site and, based thereon producing a
second ultrasound data representative of the scan plane including
the ablation site; generating, in real-time or near real-time, a
second ultrasound image based on the second ultrasound data, the
second ultrasound image being representative of the change in the
anatomical structure of a portion of the ablation site contained in
the scan plane; receiving, in real-time or near real-time,
physiology signals from the physiology catheter located proximate
the ablation site and, based thereon producing a second physiology
data representative of physiologic activity of the portion of the
ablation site contained in the scan plane; forming, in real-time or
near real-time, a second display image combining the second
ultrasound image and second physiology data and saving the second
image in the electrophysiology recording system; and forming a
volumetric ultrasound data set for a series of the scan planes, the
display image constituting a three-dimensional representation of
the ultrasound image and physiology data, wherein the ultrasound
image and physiology data combined in the display image are
obtained at a common time in a cyclical motion of the region of
interest.
36. The method of claim 35, further comprising the steps of
comparing the first and second display images of the combined
ultrasound image and physiology data, wherein the efficacy of the
ablation procedure can be determined.
37. The method of claim 35, wherein detecting a change in the
subject of interest includes determining tissue characterization as
being one of conducting and non-conducting tissue.
38. The method of claim 35, wherein the display image includes
physiology data mapped onto an anatomical structure contained in
and defined by the ultrasound image.
39. The method of claim 35, wherein the ultrasound signal is
received from an ultrasound probe constituting at least one of an
intravascular ultrasound (IVUS) catheter, an echocardiography (ICE)
catheter, a transesophageal probe, an interventional probe and a
surface probe.
40. The method of claim 35, wherein the physiology data is received
from a physiology catheter constituting at least one of an
electrophysiology (EP) catheter and a hemodynamic (HD)
catheter.
41. The method of claim 35, further comprising receiving ECG
signals from ECG leads provided on the surface of the subject;
deriving cardiac cycle data based on one of the ECG signals and
intracardiac signals obtained from an electrophysiology catheter;
and utilizing the cardiac cycle data to synchronize the ultrasound
images and physiology data.
42. The method of claim 35, further comprising tracking a position
of an ultrasound probe and a physiology catheter, and generating
tracking information denoting positions of the ultrasound probe and
physiology catheter with respect to a common reference coordinate
system.
43. The method of claim 35, further comprising registering the
ultrasound image and physiology data within a common coordinate
reference system.
44. The method of claim 35, further comprising receiving ECG
signals from ECG leads placed on a subject, and generating timing
information from the ECG signals, the timing information being
representative of cyclical points in a subject's cardiac cycle.
45. The method of claim 35, further comprising generating and
displaying new ultrasound images at a frame rate of at least seven
frames per second.
46. The method of claim 35, wherein the ultrasound image is
representative of least one of B-mode, power Doppler, color flow,
M-mode, anatomic M-mode, ARFI mode, strain and strain rate
information.
47. The method of claim 35, wherein the physiology data is denoted
in the display image as at least one of gray scale information and
color information combined with the ultrasound image.
48. The method of claim 35, further comprising accessing a lookup
table based on the ultrasound image data and physiology data to
define pixel values of the display image, the lookup table
identifying pixel values to be used in the display image based on
the ultrasound image data and physiology data.
49. The method of claim 35, further comprising presenting, in the
display image, the ultrasound image data as gray scale information
and the physiology data as color information.
50. The method of claim 35, further comprising providing a user
interface the permits an operator to designate a point on the
subject of interest, in response to the user designation,
presenting a graph of physiology data over a period of time
associated with a designated point on the region of interest.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation-in-Part of application
Ser. No. 11/204,711, filed Aug. 16, 2005 which is incorporated
herein by this reference.
FIELD OF THE INVENTION
[0002] Embodiments of the present invention generally relate to
methods and systems for combining physiology information with
ultrasound based anatomic structures. More particularly,
embodiments relate to methods and systems that construct a 2D or 3D
representation of an anatomical structure based on ultrasound data
and superimpose thereon graphical information representative of
physiologic characteristics of the anatomic structure in real-time
or near real-time during an ablation procedure.
BACKGROUND OF THE INVENTION
[0003] Ablation procedures are used to treat various conditions
including artrial fibrillation, artrial flutter, A-V nodal
re-entrant tachycardia, by-pass tract tachycardia, ventricular
tachycardia and others. Clinicians use catheters which deliver
radio frequency, cryo, laser and other forms of energy to destroy
selected tissues. Ablation size is determined by various factors
including, but not limited to, catheter contact, angle of the
catheter in relation to the selected tissue, blood flow in the
area, impedance in the setting selected by the clinician on various
ablation delivery systems. Ablation efficacy requires tissue
destruction at the catheter-tissue interface. Ablation is either
set to destroy tissue in a selected area or to permanently prevent
electrical conduction by preventing a rhythm from crossing a line
drawn by ablations termed a line of block. It is known to provide
mapping systems which can record the location of ablations but such
systems to not provide any feedback as to the status of the tissue
at the catheter tip.
[0004] Various types of physiology workstations have been proposed
such as electrophysiology (EP) workstations, hemo-dynamic (HD)
workstations, and the like. Generally, EP, HD and ablation
procedures are carried out through the use of, among other things,
EP catheters, HD catheters and mapping sensors. The procedure room
also includes a fluoroscopy system, a diagnostic ultrasound system,
a patient monitoring device and an ablation system. The ultrasound
system may utilize a variety of probes, such as ultrasound
catheters, transesophageal probes, surface probes and the like. The
ultrasound system may be used before, during or after an ablation
procedure to monitor the position of the EP catheters and/or
ablation catheters. The mapping system is utilized with physiology
catheters to detect and record desired physiologic parameters. The
mapping system includes equipment to monitor and track the position
of a mapping catheter, from which a map is created of the region of
interest.
[0005] Conventional electrophysiology mapping systems utilize a
mapping catheter positioned in a heart chamber that may include
passive and active electrode sites. The active electrode sites
impose an electric field within the chamber. The blood volume and
wall motion modulate the electric field that is detected by passive
electrode sites on the catheter. Electrophysiology measurements and
geometric measurements are taken from the catheter and used to
construct a map and to display intrinsic heart activity. Another
type of conventional mapping system utilizes an external imaging
modality such as ultrasound, SPECT, PET, MRI, CT system that is
positioned external to the patient to capture a 3D image of the
heart. The diagnostic image is captured before the heart is mapped.
The mapping system utilizes data obtained from the catheter to
generate a geometric map, with which the diagnostic image is then
registered.
[0006] Heretofore, physiology workstations have operated
independent and distinct from the mapping, ablation and ultrasound
equipment utilized during the physiology study. Also, conventional
mapping, ablation and ultrasound equipment have operated
independent and distinct from one another. The mapping, ablation,
physiology and ultrasound systems include separate computers,
monitors, and user interfaces, all of which are mounted on separate
chassis.
[0007] Thus, there is a need for a method that provides the
clinician real-time or near, real-time feedback as to the efficacy
of an ablation.
BRIEF DESCRIPTION OF THE INVENTION
[0008] In accordance with at least one embodiment, a method is
provided for obtaining real-time or near real-time feedback as to
the efficacy of an ablation procedure on a subject of interest at
an ablation site. The method includes receiving signals from an
ultrasound probe located proximate the ablation site and, based
upon the receive signals, producing ultrasound data representative
of a scan plane including the ablation site. The method further
includes generating an ultrasound image based on the ultrasound
data. The ultrasound image is representative of an anatomical
structure of a portion of the ablation site contained in the scan
plane. The method further includes receiving physiology signals
from a physiology catheter located proximate the ablation site and,
based on the physiology signals, producing physiology data
representative of physiologic activity of the portion of the
ablation site contained in the scan plane. The method further
includes forming and saving a display image by combining the
ultrasound image and physiologic data. The method further includes
detecting a change in the subject of interest proximate the
ablation site. Receiving in real-time or near real-time, signals
from the ultrasound probe located proximate the ablation site and,
based thereon producing a second ultrasound data representative of
the scan plane including the ablation site. Generating, in
real-time, or near real-time, a second ultrasound image based on
the second ultrasound data, the second ultrasound image being
representative of the change in the anatomical structure of a
portion of the ablation site contained in the scanned plant.
Receiving, in real-time or near real-time, the physiology signals
from the physiology catheter located proximate the ablation site
and, based thereon, producing a second physiology data
representative of physiologic activity of the portion of the
ablation site contained in the scanned plane. The method further
includes the forming in real-time or near real-time a second
display image combining the second physiology data in saving the
second image in the electro physiology recording system. Another
embodiment includes comparing the first and second display images
of the combined ultrasound image and physiology data, wherein the
efficacy of the ablation procedure can be determined.
[0009] There is also provided a method is provided for obtaining
real-time or near real-time feedback as to the efficacy of an
ablation procedure on a subject of interest at an ablation site.
The method includes receiving signals from an ultrasound probe
located proximate the ablation site and, based upon the receive
signals, producing ultrasound data representative of a scan plane
including the ablation site. The method further includes generating
an ultrasound image based on the ultrasound data. The ultrasound
image is representative of an anatomical structure of a portion of
the ablation site contained in the scan plane. The method further
includes receiving physiology signals from a physiology catheter
located proximate the ablation site and, based On the physiology
signals, producing physiology data representative of physiologic
activity of the portion of the ablation site contained in the scan
plane. The method further includes forming and saving a display
image by combining the ultrasound image and physiologic data. The
method further includes detecting a change in the subject of
interest proximate the ablation site. Receiving in real-time or
near real-time, signals from the ultrasound probe located proximate
the ablation site and, based thereon producing a second ultrasound
data representative of the scan plane including the ablation site.
Generating, in real-time, or near real-time, a second ultrasound
image based on the second ultrasound data, the second ultrasound
image being representative of the change in the anatomical
structure of a portion of the ablation site contained in the
scanned plant. Receiving, in real-time or near real-time, the
physiology signals from the physiology catheter located proximate
the ablation site and, based thereon, producing a second physiology
data representative of physiologic activity of the portion of the
ablation site contained in the scanned plane. The method further
includes the forming in real-time or near real-time a second
display image combining the second physiology data in saving the
second image in the electro physiology recording system. Tracking a
position of an ultrasound probe and a physiology catheter, and
generating tracking information denoting positions of the
ultrasound probe and physiology catheter with respect to a common
reference coordinate system and registering the ultrasound image
and physiology data within a common coordinate reference
system.
[0010] There is further provided a method is provided for obtaining
real-time or near real-time feedback as to the efficacy of an
ablation procedure on a subject of interest at an ablation site.
The method includes receiving signals from an ultrasound probe
located proximate the ablation site and, based upon the receive
signals, producing ultrasound data representative of a scan plane
including the ablation site. The method further includes generating
an ultrasound image based on the ultrasound data. The ultrasound
image is representative of an anatomical structure of a portion of
the ablation site contained in the scan plane. The method further
includes receiving physiology signals from a physiology catheter
located proximate the ablation site and, based on the physiology
signals, producing physiology data representative of physiologic
activity of the portion of the ablation site contained in the scan
plane. The method further includes forming and saving a display
image by combining the ultrasound image and physiologic data. The
method further includes detecting a change in the subject of
interest proximate the ablation site. Receiving in real-time or
near real-time, signals from the ultrasound probe located proximate
the ablation site and, based thereon producing a second ultrasound
data representative of the scan plane including the ablation site.
Generating, in real-time, or near real-time, a second ultrasound
image based on the second ultrasound data, the second ultrasound
image being representative of the change in the anatomical
structure of a portion of the ablation site contained in the
scanned plant. Receiving, in real-time or near real-time, the
physiology signals from the physiology catheter located proximate
the ablation site and, based thereon, producing a second physiology
data representative of physiologic activity of the portion of the
ablation site contained in the scanned plane. The method further
includes the forming in real-time or near real-time a second
display image combining the second physiology data in saving the
second image in the electro physiology recording system. Forming a
volumetric ultrasound data set for a series of the scan planes, the
display image constituting a three-dimensional representation of
the ultrasound image and physiology data, wherein the ultrasound
image and physiology data combined in the display image are
obtained at a common time in a cyclical motion of the region of
interest.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 illustrates a block diagram of a physiology system
formed in accordance with an embodiment of the present
invention.
[0012] FIG. 2 illustrates a block diagram of the functional
modules, within the ultrasound processor module, that are utilized
to carry out ultrasound mid-processing operations in accordance
with an embodiment of the present invention.
[0013] FIG. 3 illustrates a block diagram of the functional
modules, within the display processor module, that are utilized to
carry out the display processing operations in accordance with an
embodiment of the present invention.
[0014] FIG. 4 illustrates a flowchart of the process to acquire,
register and display ultrasound images in combination with
physiology data in real-time or near real-time during an ablation
procedure.
[0015] FIG. 5 illustrates an exemplary application by which
ultrasound data and physiology data may be acquired in connection
with an electrophysiology procedure within a subject of
interest.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Currently physicians cannot know if ablation has been made,
the depth of ablation or if the tissue is destroyed or merely
stunned by application of energy during an ablation procedure.
Clinicians place ablation lesions immediately adjacent to one
another in an attempt to insure that all the desired tissue had
been destroyed. Tissues typically begin to swell in the areas
surrounding ablations within minutes of energy delivery. Swollen
tissues may perform the same as destroyed tissues when tested with
contact, pacing, etc. Clinicians may place additional ablations
than what are required for the procedure to be successful in an
attempt to prevent recurrence of the original condition, these are
known as "insurance burns". Clinicians desire to destroy the
selected tissue and leave remaining tissues intact and unaffected.
Complications such as complete heart block, myocardial infarctions
and pulmonary vein stenosis, among others can occur when ablation
lesions are larger in circumference or deeper in the tissue than
intended. Conversely, if the lesions are not complete in critical
areas, the patient may receive no benefit from the ablation
procedure.
[0017] As discussed below, ultrasound systems have the capacity to
perform tissue characterization. When conductive tissue is ablated,
the character of the tissue changes from muscle, neuro fibers, etc.
to non-conducting tissue that will eventually result in scar
tissue. Giving the physician visual and/or auditory feedback as to
the efficacy and/or size and depth of an ablation attempt, would
provide key clinical data allowing the physician to adjust settings
on ablation delivery systems, change catheter position, select a
different catheter, etc.
[0018] As discussed below, clinical feedback of ablation efficacy
during ablation procedure can be provided by an ultrasound
physiology system to gather tissue characterization at the ablation
site. The system analyzes the information and provides the
clinician with the depth and diameter of fully ablated tissue as
well as the area of injury surrounding the ablation. The data may
be displayed to the clinician as numeric and/or may be displayed as
a visual indicator, for instance the clinician may see a notation
in the log of the recording system stating the ablation destroyed
tissue, alternatively the system may color code the location of the
ablation with an assigned color designating success and different
color designating inefficacy with these indicators being displayed
over an ultrasound image previously acquired using, for example, an
MR or CT system or overlayed onto a map created by a separate 3-D
mapping system.
[0019] Current ablation procedure mapping systems allow the
clinician to draw on a 3-D rendering of the subject of interest,
for example, a heart, where ablations have been performed. These
marks are cartoon depictions of where energy has been delivered;
however, they provide no information to the clinician other than
the location. Providing the clinician with information of the
properties (characterization) of tissues during and after ablation
allows a clinician to know if energy delivery has created a
complete line of block and/or destroyed the desired tissues
preventing complications and the need for repeat procedures as well
as negating the need for "insurance burns" thereby decreasing
procedure time.
[0020] FIG. 1 illustrates a physiology system 10 formed in
accordance with an embodiment of the present invention. A system
controller 8 manages the overall interaction and operation of the
various modules, accessories and the like. The physiology system 10
includes a beam former module 12 configured to be joined with one
or more ultrasound probes 14-16. Examples of ultrasound probes may
include an intravascular ultrasound (IVUS) catheter 14, an
echocardiography (ICE) catheter, a transesophageal probe 15, an
interventional probe, an ultrasound surface probe 16 and the like.
The beam former module 12 controls transmit and receive operations
to and from the probes 14-16. A physiology signal processing module
20 is provided and joined with one or more catheters 22-24.
Examples of catheters include a basket catheter 22, a multi-pole
electrophysiology catheter 23 (e.g. a 4-pole, 8-pole, 10-pole, 20
pole and the like), a hemodynamic catheter 24 and the like.
[0021] The beam former module 12 processes radio frequency (RF)
echo signals from one or more of probes 14-16 and produces there
from I, Q data pairs associated with each data sample within a scan
plane through the region of interest. The beam former module 12 may
supply the I, Q data pairs directly to the ultrasound processor
module 30. Alternatively or in addition, the beam former module 12
may store the collection of I, Q data pairs defining the sample
points within a single scan plane in the ultrasound data memory 38
as raw ultrasound data. The ultrasound data memory 38 stores the I,
Q data pairs for individual scan planes as two dimensional data
sets, or alternatively for collections of scan planes as three
dimensional data sets.
[0022] The ultrasound processor module 30 processes the raw I, Q
data pairs, as explained below in more detail, to form ultrasound
images (2D or 3D). For example, the ultrasound processor module 30
may form B-mode images, color flow images, power Doppler images,
spectral Doppler images, M-mode images, ARFI images, strain images,
strain rate images and the like. The ultrasound images contain
ultrasound image data representing voxels associated with data
samples from the region of interest, where the ultrasound image
data may be defined in Cartesian or polar coordinates. The
ultrasound images may be stored individually as two dimensional
data sets. Alternatively, collections of ultrasound images may be
stored as three dimensional data sets. The beam former module 12
and ultrasound processor module 30 processes the signals from the
ultrasound probe in real-time during a physiology procedure in
order that the display 48 is able to display and continuously
update the ultrasound image in real-time during the physiology
procedure. By way of example, the ultrasound processor module may
generate new ultrasound images at a frame rate of at least seven
frames per second such that the display processor module is able to
update the ultrasound image information within the displayed image
at a frame rate of at least seven frames per second. Alternatively,
the frame rate, at which new ultrasound images are generated and
displayed, may be increased to 16, 32 or 64 frames per second or
higher.
[0023] The physiology signal processor 20 passively and/or actively
operates upon one or more of the catheters 22-24 to measure
physiology signals. The physiology signal processor module 20
receives physiology signals from one or more of the catheters 22-24
and produces physiology data representative of the physiologic
activity of a portion of the regions of interest proximate the
sensors on the corresponding catheter 22-24. The physiology data is
stored in physiology data memory 40.
[0024] ECG leads 26 are provided on the surface of the subject and
produce ECG signals that are received by the physiology signal
processor module 20 and/or to a cardiac cycle detection module 28.
The cardiac cycle detection module 28 monitors the cardiac activity
denoted by the ECG signals and generates therefrom timing
information representative of cyclical points in the subject's
cardiac cycle. The timing information is provided to the physiology
signal processor module 20 and to the ultrasound processor module
30. Alternatively, intracardiac signals obtained from EP catheters
may provide the cardiac cycle detection signal.
[0025] A position tracking module 32 is joined with a series of
detectors 34 that may operate as transmitters and/or receivers. The
position tracking module 32, optionally, may also receive position
information from one or more of the ultrasound probes 14-16 and/or
physiology catheters 22-24. In the example of FIG. 1, the
ultrasound probes 14-16 are each provided with first and second
reference point elements (denoted RP1 and RP2 on each probe and
catheter). The reference point elements may represent transmitters
and/or receivers configured to transmit or receive acoustic energy,
radio frequency energy, electromagnetic energy and the like.
Alternatively, only a single reference point element or sensor may
be provided on one or more of the probes and catheters. Examples of
conventional sensor configurations and detector systems are
described in U.S. Pat. No. 5,713,946 to Ben-Haim; U.S. Pat. No.
6,216,027 to Willis et al.; U.S. Pat. No. 5,662,108 to Budd et al.;
U.S. Pat. No. 5,409,000 to Imran; U.S. Pat. No. 6,650,927 to
Keidar; U.S. Pat. No. 6,019,725 to Vesely; U.S. Pat. No. 5,445,150
to Dumoulin, all of which are expressly incorporated herein in
their entireties by reference.
[0026] The position tracking module 32 generates tracking
information defining the position of each ultrasound probe and each
physiology catheter with respect to a common reference coordinate
system. By way of example, the position information may include XYZ
coordinates for each reference point element within a common
three-dimensional Cartesian coordinate system. Alternatively, the
position information may be defined in polar coordinate within a
common three-dimensional polar coordinate system. The tracking
information may uniquely identify each reference point element,
such as through a unique transmit signature and the like. The
position tracking module 32 may include a relational table
containing an ID for each reference point element uniquely
associated with probe/catheter descriptive information (e.g. the
serial number, type, dimensions, shape and the like). The tracking
information may also include orientation information (e.g. pitch
roll and yaw) describing the orientation of a reference axis 17 of
a probe or catheter relative to the reference coordinate
system.
[0027] The position tracking module 32 repeatedly monitors and
tracks the reference point element, to generate a continuous stream
of coordinate position data sets, wherein a single combination of
XYZ values represent a single coordinate position data set.
Optionally, the position tracking module 32 may record, with each
coordinate position data set, a time stamp indicating a time at
which the coordinate position data set was obtained. The time stamp
may be defined by a system clock 36 that also provides reference
timing information to the physiology signal processor module 20 and
ultrasound processor module 30. Alternatively, the time stamp may
be defined with respect to the cardiac cycle the patient (e.g. X
seconds following/preceding the peak of the R-wave). When the
timing information is defined based on the cardiac cycle, cardiac
cycle timing information is provided by the cardiac cycle detection
module 28 to each of the physiology signal processor module 20,
ultrasound processor module 30 and position tracking module 32.
[0028] The position tracking module 32 may provide the position
information, orientation information and timing information
(collectively referred to as "tracking information") to the
physiology and ultrasound processor modules 20 and 30. When the
tracking information is provided to the ultrasound processor module
30, the ultrasound processor module 30 stores the tracking
information with the ultrasound image in the ultrasound data memory
38. The tracking information uniquely identifies the time at which
the ultrasound image was acquired, as well as the position and/or
orientation of the ultrasound probe 14-16 at the time of
acquisition. When the tracking information is provided to the
physiology processor module 20, the physiology processor module 20
records the tracking information with the physiology data in the
physiology data memory 40. The tracking information uniquely
identifies the time at which the physiology data was acquired, as
well as the position and/or orientation of the physiology
catheter(s) 22-24 at the time of acquisition.
[0029] A registration module 42 accesses the ultrasound and
physiology data memories 38 and 40 to obtain one or more ultrasound
images and related physiology data sets acquired at the same
point(s) in time. The ultrasound images and associated physiology
data sets are identified from memories 38 and 40 based on the
recorded time stamps. The registration module 42 transforms one or
both of the ultrasound image and physiology data into a common
coordinate system and stores the results in a common data memory
44. By way of example, the registration module 42 may map the
physiology data set into the coordinate system defined by the
ultrasound images as stored in the ultrasound data memory 38.
Alternatively, the registration module 42 may map the ultrasound
images into the coordinate system defined by the physiology data
sets as stored in the physiology data memory 40. As a further
alternative, the registration module 42 may transform both the
ultrasound images and physiology data sets into a new coordinate
system.
[0030] A display processor module 46 accesses the common data
memory 44 to obtain select combinations of ultrasound images and
physiology data sets for presentation on display 48. The display
processor module may form a display image combining the ultrasound
image and physiology data set, such that the physiology data is
mapped on to an anatomical structure contained in, and defined by,
the ultrasound image. Optionally, the display processor module 46
may access a lookup table 50 that is stored as part of, or separate
from, the common data memory 44 to define display characteristics,
such as transparency, opacity, color, brightness and the like, for
individual display pixels defining the resultant display image.
[0031] The lookup table 50 may be used to define data samples or
voxels within the ultrasound image through one of gray scale and
color information, and to define the physiology data through the
other of gray scale and color information. Optionally, one
combination or range of colors may be designated to denote
ultrasound information, while a separate combination or range of
colors may be designated to denote physiology data. As a further
option, the brightness, intensity or opacity of each pixel in the
display image may be varied in accordance with one or both of the
value of the ultrasound information and the value of the physiology
data. For example, the ultrasound image may be defined by B-mode
data values for each data point or voxel, while the physiology data
associated with the data point or voxel may be defined by one or
more colors within a range of colors (e.g., ranging from blue to
red, or ranging from light blue to dark blue, or ranging from light
red to dark red). Alternatively, the ultrasound image may be
defined by non B-mode data values, such as anatomic M-mode, strain
or strain rate characteristics of the anatomic structure, with the
strain or strain rate being represented in the display image by
discrete colors within a range of colors (e.g., ranging from blue
to red, or ranging from light blue to dark blue, or ranging from
light red to dark red). When the anatomic structure is represented
in the display image by discrete colors, the physiology data may be
represented through variations of the brightness at each display
pixel.
[0032] A user interface 52 to is provided to control the overall
operation of the physiology system 10. The user interface 52 may
include, among other things, a keyboard, mouse and/or trackball.
The user interface 52 may permit an operator to designate a portion
of the ultrasound image, for which physiologic data is of interest.
The display processor module 46 and/or physiology signal processor
module 20 may then generate a separate physiology graph to be
displayed independent and distinct from the ultrasound image. For
example, the display 48 may present an ultrasound image as a B-mode
sector scan, with one or more points of interest on the B-mode
sector scan designated. A separate graph may be co-displayed on
display 48 with the ultrasound B-mode image.
[0033] FIG. 2 illustrates an exemplary block diagram of the
ultrasound processor module 33 of FIG. 1 formed in accordance with
an embodiment of the present invention. The operations of the
modules illustrated in FIG. 2 may be controlled by a local
ultrasound controller 87 or by the system controller 8. The modules
49-59 perform mid-processor operations.
[0034] The ultrasound processor module 30 obtains ultrasound data
21 from the ultrasound data memory 38 or the beam former module 12
(FIG. 1). The received ultrasound data 21 constitutes I, Q data
pairs representing the real and imaginary components associated
with each data sample. The I, Q data pairs are provided to an ARFI
module 49, a color-flow module 51, a power Doppler module 53, a
B-mode module 55, a spectral Doppler module 57 and M-mode module
59. Optionally, other modules may be included such as a strain
module, a strain rate module and the like. Each of modules 49-59
process the I, Q data pairs in a corresponding manner to generate
ARFI data 60, color-flow data 61, power Doppler data 63, B-mode
data 65, spectral Doppler data 67, and M-mode data 69, all of which
are stored in ultrasound data memory 38. Alternatively, the
ultrasound data memory 38 may be divided such that the raw I, Q
data pairs are stored in raw data memory, while the processed image
data is stored in separate image data memory. The ARFI, color-flow,
power Doppler, B-mode, spectral Doppler and M-mode data 60-69 may
be stored as sets of vector data values, where each set defines an
individual ultrasound image frame. The vector data values are
generally organized based on the polar coordinate system.
[0035] FIG. 3 illustrates an exemplary block diagram of the display
processor module 46 of FIG. 1 formed in accordance with an
embodiment of the present invention. The operations of the modules
illustrated in FIG. 3 may be controlled by the local ultrasound
controller 87 or by the system controller 8. The modules 73, 77 and
81 perform display-processor operations. A scan converter module 73
reads from memory 44 the vector data values associated with one or
more image frames and converts the set of vector data values to
Cartesian coordinates to generate an display image frame 75
formatted for display. The ultrasound image frames 75 generated by
scan converter module 73 may be passed to a temporary area in
memory 44 for subsequent processing or may be passed directly to
one of the 2-D and 3-D processor module's 77 and 81. As an example,
it may be desired to view a B-mode ultrasound image in real-time
associated with the ultrasound signals detected by an ultrasound
catheter. To do so, the scan converter obtains B-mode vector data
sets for images stored in memory 44. The B-mode vector data is
interpolated where necessary and converted into the X,Y format for
video display to produce ultrasound image frames. The scan
converted ultrasound image frames are passed to the video processor
module 77 that maps the video to a grey-scale mapping for video
display.
[0036] The grey-scale map may represent a transfer function of the
raw image data to displayed grey levels. Once the video data is
mapped to the grey-scale values, the video processor module 77
controls the display 48 to display the image frame in real-time.
The B-mode image displayed in the real-time is produced from an
image frame of data in which each datum indicates the intensity or
brightness of a respective pixel in the display. The display image
represents the tissue and/or blood flow in a plane through the
region of interest being imaged.
[0037] The color-flow module 51 (FIG. 2) may be utilized to provide
real-time two-dimensional images of blood velocity in the imaging
plane. The frequency of sound waves reflected from the inside of
the blood vessels, heart cavities, etc., is shifted in proportion
to the velocity of the blood vessels; positively shifted for cells
moving toward the transducer and negatively shifted for cells
moving away from the transducer. The blood velocity is calculated
by measuring the phase shift from firing to firing at a specific
range gate. Mean blood velocity from multiple vector positions and
multiple range gates along each vector are calculated and a
two-dimensional image is made from this information. The color-flow
module 51 receives the complex I, Q data pairs from the beamformer
module 12 and processes the I, Q data pairs to calculate the mean
blood velocity, variance (representing blood turbulence) and total
pre-normalized power for all sample volumes within the operator
defined region.
[0038] The 2D video processor module 77 combines one or more of the
frames generated from the different types of ultrasound information
and physiologic data. For example, the 2D video processor modules
77 may combine a B-mode image frame and a color representation of
the physiologic data by mapping the B-mode data to a grey map and
mapping the physiologic data to a color map for video display. In
the final displayed image, the color pixel data is superimposed on
the grey scale pixel data to form a single multi-mode image frame
79 that may be re-stored in memory 44 or passed over bus 35 to the
display 48. Successive frames of B-mode images, in combination with
the associated physiology data, may be stored as a cine loop in
memory 44. The cine loop represents a first in, first out circular
image buffer to capture image data that is displayed in real-time
to the user. The user may freeze the cine loop by entering a freeze
command at the user interface 52. The user interface 52 represents
a keyboard and mouse and all other commands associated with
ultrasound system user interface.
[0039] The spectral Doppler module 57 (FIG. 2) operates upon the I,
Q data pairs by integrating (summing) the data pairs over a
specified time interval and then sampling the data pairs. The
summing interval and the transmission burst length together define
the length of the sample volume which is specified by the user at
the user interface 52. The spectral Doppler module 57 may utilize a
wall filter to reject any clutter in the signal which may
correspond to stationery or very slow moving tissue. The filter
output is then fed into a spectrum analyzer, which may implement a
Fast Fourier Transform over a moving time window of samples. Each
FFT power spectrum is compressed and then output by the spectral
Doppler module 57 to memory 44. The 2D video processor module 77
then maps the compressed spectral Doppler data to grey scale values
for display on the display 48 as a single spectral line at a
particular time point in the Doppler velocity (frequency) versus a
time spectrogram. The 2-D video processor module 77 may similarly
map the physiology data into a graph representing electrical
potential fluctuation (along the vertical axis) and time (along the
horizontal axis).
[0040] A 3D processor module 81 is also controlled by user
interface 52 and accesses memory 44 to obtain spatially consecutive
groups of ultrasound image frames and to generate three dimensional
image representation thereof, such as through volume rendering or
surface rendering algorithms. The three dimensional images may be
generated utilizing various imaging techniques, such as
ray-casting, maximum intensity pixel projection and the like.
[0041] FIG. 4 illustrates a,processing sequence carried out by the
physiology system 10 of FIG. 1 in connection with acquiring,
tracking and combining ultrasound and physiology data in real-time
or near real-time during an ablation procedure. At 400, the
position tracking module 32 registers the ultrasound probe 14-16
within the position tracking coordinate system. At 402, the
position tracking module 32 registers the physiology catheters
within the position tracking coordinate system. At 404, the beam
former module 12 acquires RF echo signals from one or more scan
planes of the abalation site and generates I, Q data pairs of
therefrom. At 406, the ultrasound processor module 30 accesses the
raw I, Q data pairs and forms ultrasound data images therefrom
based upon the desired mode of operation (as discussed above in
connection with FIG. 2).
[0042] At 408, the position tracking module 32 provides tracking
information to the ultrasound processor module 30. The tracking
information may include a unique time stamp and/or reference point
data identifying the position and/or orientation of one or more
reference point elements RP1, RP2 on the corresponding ultrasound
probe 14-16. The tracking information is stored in memory 38 by the
ultrasound processor module 30 with the ultrasound image data.
[0043] At 410, the physiology signal processor module 20 acquires
physiology data, and at 412, forms a physiology image data set. At
414, the position tracking module 32 provides tracking information
(e.g. time stamps and reference point data) to the physiology
signal processor module 20. The physiology image data set and
tracking information are stored by the physiology signal processor
module 20 in physiology data memory 40.
[0044] At 416, the registration module 42 accesses the ultrasound
and physiology data memories 38 and 40, and transforms or maps the
ultrasound and physiology image data into a common coordinate
reference system. Once mapped to a common coordinate reference
system, the ultrasound and physiology image data are stored in a
common data memory 44. At 418, the display processor module 46
performs display processing upon the ultrasound physiology image
data to form a combined ultrasound and physiology display image. At
420, the display 48 presents the combined ultrasound and physiology
image for viewing.
[0045] At 422, the previously displayed image is stored in the
electrophysiology recording system. At 424, the physiology system
10 detects a change in rhythm of the subject of interest produced
by a change in cardiac dimensions. At 426, a tracking coordinate
system 32 is decoupled from previously acquired combined image.
[0046] At 428, the beam former module 12 acquires RF echo signals
from one or more scan plans of the ablation site and generates I,Q
data pairs of therefrom creating a second set of ultrasound data
points. At 430, the ultrasound processor module 30 accesses the raw
I,Q data peers and forms a second ultrasound data image therefrom
based upon the desired mode of operation (as discussed above in
connection With FIG. 2).
[0047] At 432, the physiology signal processor module 20 acquires
physiology data and forms a second physiology image data set. At
434, the position tracking module 32 provides tracking information
(example time stamps and reference point data) to the physiology
signal processor module 20. The second physiology image data set
and tracking information are stored by the physiology signal
processor module 20 in physiology data memory 40.
[0048] At 436, the registration module 42 accesses the ultrasound
and physiology data memories 38 and 40, and transforms or maps the
second ultrasound and second physiology image data into a common
coordinate reference system. Once mapped to a common coordinate
reference system, the second ultrasound and second physiology image
data are stored in a common data memory 44. At 438, the display
processor module.46 performs display processing upon the second
ultrasound physiology image data to form a combined ultrasound and
physiology display image. At 440, the display 48 presents the
combined ultrasound and physiology image for viewing wherein the
first and second display images of the combined ultrasound image
and physiology data obtained, in real-time or near real-time,
during the ablation procedure to determine the efficacy of the
ablation procedure.
[0049] FIG. 5 illustrates an exemplary application in which the
above described embodiments may be utilized. The graphical
representation of a heart 500 is illustrated. An ultrasound
catheter 502 and EP catheter 504 have been inserted through the
inferior vena cava (IVC) into the right atrium (RA). The ultrasound
and EP catheters 502 and 504 have passed through a punctured
opening through the fossa ovalis into the left atrium (LA). The
ultrasound catheter 502 includes a series of spaced apart piezo
transducers 506 that may be separately activated and controlled to
transmit and receive ultrasound data for corresponding scan planes.
The ultrasound catheter 502 and EP catheter 504 are utilized to map
the anatomical contour of, and electrical activity at, the interior
wall of the left atrium, including proximate the openings to the
pulmonary veins denoted at 508 and 510. It should be understood
that other areas of the heart can be monitored by the method
described herein, for example, imaging from the right side to the
left--the US catheter would stay in the HRA and visualize across
the septum to the LA where the ablation catheter would be
placed.
[0050] ARFI allows examination of the functionality of tissue
subsets, such as in the heart, organs, tissue, vasculature and the
like. ARFI is a phenomenon associated with the propagation of
acoustic waves through a dissipative medium. It is caused by a
transfer of momentum from the wave to the medium, arising either
from absorption or reflection of the wave. This momentum transfer
results in the application of a force in the direction of wave
propagation. The magnitude of this force is dependent upon both the
tissue properties and the acoustic beam parameters. The duration of
the force application is determined by the temporal profile of the
acoustic wave. ARFI images the response of tissue to acoustic
radiation force for the purpose of characterizing the mechanical
properties of the tissue. When the duration of the radiation force
is short (less than 1 millisecond), the tissue mechanical impulse
response can be observed. ARFI imaging has many potential clinical
applications, including: detecting and characterizing a wide
variety of soft tissue lesions, and identifying and characterizing
atherosclerosis, plaque, and thromboses.
[0051] The term "co-displays" is not limited to displaying
information on a common CRT or monitor, but instead refers also to
the use of multiple monitors located in immediately adjacent one
another to facilitate substantially simultaneous viewing by a
single individual. The term "processor" is not intended to be
limited to a single processor or CPU.
[0052] The various blocks and modules are illustrated as
conceptually functional units only, but may be implemented
utilizing any combination of dedicated or non-dedicated hardware
boards, DSPs, processors and the like. Alternatively, the blocks
and modules may be implemented utilizing an off-the-shelf PC with a
single processor or multiple processors, with the functional
operations distributed between the processors. As a further option,
the blocks and modules may be implemented utilizing a hybrid
configuration in which certain modular functions are performed
utilizing dedicated hardware, while the remaining modular functions
are performed utilizing an off-the shelf PC and the like.
[0053] It is understood that the operations illustrated in any
processing sequences or flowcharts may be carried out in any order,
including in parallel.
[0054] The figures illustrate diagrams of the functional blocks of
various. The functional blocks are not necessarily indicative of
the division between hardware circuitry. Thus, for example, one or
more of the functional blocks (e.g., processors or memories) may be
implemented in a single piece of hardware (e.g., a general purpose
signal processor or a block or random access memory, hard disk, or
the like). Similarly, the programs may be stand alone programs, may
be incorporated as subroutines in an operating system, may be
functions in an installed imaging software package, and the
like.
[0055] For purposes of this disclosure, the term "real-time" refers
to the changes in tissue being readily apparent to the clinician as
the ablation procedure continues. For example, a physician creates
a burn at the ablation site, at the completion of that burn the
physician sees an indicator which indicates if the burn was
successful for the intended purpose. In other words, before
completion of the ablation procedure. The indicator may also
provide the dimension of the burn as the ablation procedure
continues. The term "near, real-time" refers to the system ability
to provide feedback to the clinician about the ablation procedure
at the ablation site, but not immediately following or during the
ablation procedure. For example, the clinician may wait for one to
two minutes while the system provides the information or the
clinician may assess all of the burns performed at the end of the
procedure, but prior to the catheter being removed. In the latter
example, the data from the system may not be provided to the
clinician for as long as ten minutes.
[0056] For purposes of this disclosure, the term "coupled" means
the joining of two components (electrical or mechanical) directly
or indirectly to one another. Such joining may be stationary in
nature or movable in nature. Such joining may be achieved with the
two components (electrical or mechanical) and any additional
intermediate members being integrally formed as a single unitary
body with one another or with the two components or the two
components and any additional member being attached to one another.
Such joining may be permanent in nature or alternatively may be
removable or releasable in nature
* * * * *