U.S. patent application number 15/689950 was filed with the patent office on 2018-03-15 for system and method for determining the position of the tip of a medical catheter within the body of a patient.
The applicant listed for this patent is MediGuide Ltd.. Invention is credited to Uzi Eichler.
Application Number | 20180070855 15/689950 |
Document ID | / |
Family ID | 42233618 |
Filed Date | 2018-03-15 |
United States Patent
Application |
20180070855 |
Kind Code |
A1 |
Eichler; Uzi |
March 15, 2018 |
System and method for determining the position of the tip of a
medical catheter within the body of a patient
Abstract
Method and system for determining the current position of a
selected portion of a medical catheter inserted into a tubular
organ of the body of a patient, the method comprising the
procedures of inserting a medical positioning system (MPS) catheter
into the tubular organ, acquiring a plurality of mapping positions
within the tubular organ, displaying a mapping position
representation of the mapping positions, constructing a mapping
path according to the mapping positions, inserting the medical
catheter into the tubular organ until the selected portion reaches
the initial position, displaying an operational image of the
tubular organ, a path representation of the mapping path, and an
initial position representation of the initial position
superimposed on the operational image, registering the selected
portion with the initial position, measuring a traveled length of
the medical catheter within the tubular organ from the initial
position, and estimating the current position.
Inventors: |
Eichler; Uzi; (Haifa,
IL) |
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Applicant: |
Name |
City |
State |
Country |
Type |
MediGuide Ltd. |
Haifa |
|
IL |
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|
Family ID: |
42233618 |
Appl. No.: |
15/689950 |
Filed: |
August 29, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13130377 |
May 20, 2011 |
9775538 |
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PCT/US2009/066653 |
Dec 3, 2009 |
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15689950 |
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61119502 |
Dec 3, 2008 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 5/0066 20130101;
A61B 6/504 20130101; A61B 5/6876 20130101; A61B 8/4254 20130101;
A61B 6/5247 20130101; A61B 5/7285 20130101; A61M 25/0108 20130101;
A61B 8/12 20130101; A61B 5/743 20130101; A61B 5/0402 20130101; A61B
8/5238 20130101; A61B 8/4245 20130101; A61B 34/20 20160201; A61B
5/6852 20130101; A61B 2034/2051 20160201; A61B 5/06 20130101; A61B
5/055 20130101; A61B 5/062 20130101; A61B 6/12 20130101; A61B 5/066
20130101 |
International
Class: |
A61B 5/06 20060101
A61B005/06; A61B 8/00 20060101 A61B008/00; A61B 5/00 20060101
A61B005/00; A61B 6/00 20060101 A61B006/00; A61B 8/08 20060101
A61B008/08; A61B 8/12 20060101 A61B008/12 |
Claims
1.-22. (canceled)
23. A method for determining a current position of a selected
portion of a medical catheter inserted into an organ, the method
comprising: acquiring a plurality of mapping positions of a Medical
Positioning System (MPS) catheter within the organ according to
output from a sensor included on the MPS catheter, the sensor
electrically coupled with an MPS, a selected one of the mapping
positions being defined as an initial position of a mapping path;
measuring a traveled length of the medical catheter within the
organ from the initial position; and estimating a current
three-dimensional position of the selected catheter portion
according to the traveled length, according to the plurality of
mapping positions, and according to a plurality of calculated
distances between each of the mapping positions and the initial
position, along the mapping path.
24. The method according to claim 23, further comprising acquiring
a pre-operational image of the organ, by an imager.
25. The method according to claim 24, further comprising
registering a three-dimensional coordinate system associated with
the MPS with a two-dimensional coordinate system associated with
the pre-operational image.
26. The method according to claim 23, further comprising acquiring
an operational image of the organ, after constructing the mapping
path, to enable display of a representation of the at least one
mapping path, on the operational image.
27. The method according to claim 26 further comprising
superimposing the representation of the at least one mapping path
on the operational image.
28. The method according to claim 27, further comprising displaying
a superimposed operational image of the representation of the at
least one mapping path on the operational image.
29. The method according to claim 23, further comprising
registering a tip of the medical catheter with the initial
position.
30. The method according to claim 23, further comprising acquiring
an organ timing signal of the organ.
31. The method according to claim 30, further comprising acquiring
a plurality of pre-operational images of the organ, according to
the organ timing signal.
32. The method according to claim 31, further comprising
registering each of the plurality of mapping positions with
respective two-dimensional coordinates of a respective
pre-operational image.
33. The method according to claim 30, further comprising grouping
the mapping positions into respective mapping position groups, each
of the mapping position groups being associated with a respective
point in the organ timing signal.
34. The method according to claim 30, further comprising: acquiring
a plurality of pre-operational images of the organ; and associating
each of the pre-operational images with a respective point in the
organ timing signal.
35. A method for determining a current position of a selected
portion of a medical catheter inserted into an organ, the method
comprising: acquiring an organ timing signal of the organ;
acquiring a plurality of mapping positions of a Medical Positioning
System (MPS) catheter within the organ according to output from a
sensor included on the MPS catheter, the sensor electrically
coupled with an MPS, a selected one of the mapping positions being
defined as an initial position of a mapping path, wherein the
plurality of mapping positions are grouped into a respective
mapping position group based on the organ timing signal; measuring
a traveled length of the medical catheter within the organ from the
initial position; and estimating a current three-dimensional
position of the selected catheter portion according to the traveled
length, according to the plurality of mapping positions, and
according to a plurality of calculated distances between each of
the mapping positions within a respective mapping position group
and the initial position, along the mapping path.
36. The method according to claim 35, further comprising acquiring
a plurality of pre-operational images of the organ, according to
the organ timing signal.
37. The method according to claim 36, further comprising
registering each of the plurality of mapping positions with
respective two-dimensional coordinates of a respective
pre-operational image.
38. The method according to claim 35, further comprising grouping
the mapping positions into respective mapping position groups, each
of the mapping position groups being associated with a respective
point in the organ timing signal.
39. The method according to claim 35, further comprising: acquiring
a plurality of pre-operational images of the organ; and associating
each of the pre-operational images with a respective point in the
organ timing signal.
40. A system for determining a position of a selected portion of a
first elongate medical device, the system comprising: a first
elongate medical device that includes a selected portion; a second
elongate medical device that is sensor enabled, wherein a position
of the second elongate medical device is determined by a medical
positioning system (MPS); a traveled length detector operably
coupled with the first elongate medical device, wherein a
determination is made that the selected portion of the first
elongate medical device has been inserted into an organ to a known
location based on the position of the second elongate medical
device and a measurement obtained from the traveled length
detector.
41. The system of claim 40, wherein the traveled length detector
includes at least one of an interferometric system, an
electromechanical system, and a variable electro-resistive
system.
42. The system of claim 40, wherein the selected portion of the
first elongate medical device is registered with the position of
the second elongate medical device, wherein the position of the
elongate medical device is an initial position.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional
application No. 61/119,502, filed 3 Dec. 2008, which is hereby
incorporated by reference as though fully set forth herein.
FIELD OF THE DISCLOSED TECHNIQUE
[0002] The disclosed technique relates to medical devices in
general, and to methods and systems for determining the position
and orientation of the tip of a catheter, in particular.
BACKGROUND OF THE DISCLOSED TECHNIQUE
[0003] Cardiac operations, such as angioplasty, stent deployment
and ablation can be performed in a minimally invasive surgery (MIS)
setting, by employing a catheter of the appropriate type. A
surgeon, who performs a MIS, needs to observe the position and
orientation of the tip of the catheter, continuously, in order to
navigate the catheter to a desired location within the heart of the
patient.
[0004] Methods and systems for determining the position and
orientation of the tip of a catheter are known in the art. For
example, such systems employ an electromagnetic sensor mounted at
the tip of the catheter, and a medical positioning system (MPS), to
determine the position and orientation of the tip of the catheter,
according to an output of the electromagnetic sensor. The MPS
determines the position of the tip of the catheter, within a vessel
of the heart, where images are acquired by an invasive medical
imager, from inside of the vessel.
[0005] One example of invasive medical imagers is an intravascular
ultrasound (IVUS) imager, which is located at the tip of an IVUS
catheter, to produce a plurality of images from inside the vessel.
The IVUS imager employs an ultrasonic transducer at a tip of the
IVUS catheter, to acquire the images. The IVUS catheter is inserted
into the vessel, and advanced toward a region of interest within
the body of the patient. The IVUS imager acquires a plurality of
ultrasonic images during pull-back of the catheter from the region
of interest, while the MPS detects the position of the tip of the
IVUS catheter with respect to each of the ultrasonic images. A
processor, which is connected with the IVUS imager and with the
MPS, produces a video image of the inside of the vessel, according
to the ultrasonic images, and the detected positions of the tip of
the IVUS catheter. The IVUS catheter is employed in diagnosis and
treatment of different diseases, such as atheroma,
arteriosclerosis, and as an adjunct to balloon angioplasty and in
guiding stent deployment.
[0006] U.S. Pat. No. 6,246,898 B1 issued to Vesely et al. and
entitled "Method for Carrying out a Medical Procedure Using a
Three-dimensional Tracking and Imaging System" is directed to a
method for tracking the position and motion of a catheter, by
employing a three-dimensional (3-D) tracking and imaging system.
The 3-D tracking and imaging system includes a plurality of mobile
transducers, a plurality of reference transducers, a computer
system, an instrument, and an optional robotics subsystem. The
computer system includes a 3-D tracking system, an imaging modality
system, an image registration system, an image warping system and
geometry transformation system, a user interface, and a display.
The optional robotics subsystem includes a robotics control system
and a robotic manipulator system. The instrument is a diagnostic
tool such as a catheter. The robotics control subsystem controls
the robotic manipulator system, which physically moves the
instrument.
[0007] The mobile transducers are fitted onto the instrument. The
reference transducers are mounted to locations on the patient in
strategic reference locations. The imaging modality system acquires
4-D image data from a magnetic resonance imager (MRI). The position
and movement of the instrument is tracked by the 3-D tracking
system. The 3-D tracking system employs triangulation algorithms to
determine the relative spatial coordinates of a combination of two
transducers according to the time-of-flight principle of ultrasonic
waves. The image registration system registers the position of the
instrument with the corresponding spatial coordinates within the
acquired images, provided by the imaging modality system. The image
warping and geometry transformation system warps the image data to
compensate for the changes that occurred in the period of time
between image acquisition and surgery. The user interface enables
user interaction with the computer system and the display displays
the images provided by the image registration system.
[0008] An article by Jourdain, Melissa et al. "3D Reconstruction of
an IVUS Transducer Trajectory with a Single View Cineangiography."
Medical Imaging 2005: Image Processing, Proc. of SPIE 5747 (2005)
is directed to a method for determining the three-dimensional
trajectory of an IVUS transducer during an intervention by
utilizing a single X-ray image and using a pullback distance of the
ultrasound transducer as a priori information.
[0009] The method employs two imaging modalities, IVUS imaging and
X-ray imaging. The IVUS imaging modality produces a sequence of
cross-sectional images of a lumen within the body of a patient and
the X-ray imaging modality produces a single-view X-ray image
sequence. The method employs a single-plane model, a trajectory
pruning technique and a tracking algorithm. The single-plane model
utilizes a full perspective camera model and the knowledge of a
pullback distance of a catheter inserted within a lumen of the body
of a patient. The full perspective camera model is used as a basis
for computing the projection of the position of the IVUS transducer
in an X-ray plane. The trajectory pruning technique employs a cost
function, and considers possible trajectories of the IVUS
transducer on the X-ray plane. These possible trajectories are
partly based on the curvature of the lumen. The cost function
assigns specific weights to the solutions of possible trajectories
based on the number of turns in the trajectory of the catheter.
[0010] The starting position of the IVUS transducer is inputted
into the tracking algorithm. The tracking algorithm tracks the IVUS
transducer by employing an image-differencing method (i.e., changes
in pixel intensity) between consecutive frames in the image
sequence. A 3-D position of the catheter is retrieved based on its
previously-known position, outputted by the tracking algorithm, and
with the known pullback distance of the catheter.
[0011] U.S. Pat. No. 5,724,978 issued to Tenhoff, entitled
"Enhanced Accuracy of Three-dimensional Intraluminal Ultrasound
(ILUS) Image Reconstruction" is directed to a method and apparatus
for imaging an organ in a body of a patient, in order to obtain a
three-dimensional image reconstruction from an acquired set of
echographic data. The apparatus includes an ultrasound imaging
catheter system and a catheter tracking system. The ultrasound
imaging system employs a conventional intraluminal catheter with an
imaging tip. The tracking system includes an ultrasound transducer.
The ultrasound transducer is mounted adjacent to the imaging tip of
the catheter. The imaging tip of the catheter acquires echographic
images.
[0012] The catheter is inserted into the body of the patient and
advanced into a required region of interest. The ultrasound
transducer acquires an echographic data set (i.e., a sequence of
2-D images) within the region of interest during a pull-back
procedure of the catheter. The tracking system tracks the position
of the ultrasound transducer. The position of the ultrasound
transducer with respect to each echographic data set at each point,
during image acquisition along the pull-back path of the catheter,
is calculated by determining a tangent to the catheter centerline
of the ultrasound transducer, at each of the respective locations
where the echographic data sets are acquired. The calculated
position of the catheter is used to determine a three-dimensional
pull-back trajectory of the catheter. The acquired sequence of the
2-D images is stacked in order to generate a 3-D reconstruction
from the ultrasound images. Non-linear paths of the catheter are
taken into account to avoid errors in the 3-D image
reconstruction.
[0013] U.S. Pat. No. 6,148,095 issued to Prause et al., entitled
"Apparatus and Method for Determining Three-dimensional
Representations of Tortuous Vessels" is directed to an apparatus
and a method for three-dimensional reconstructions of tortuous
vessels employing IVUS and data fusion with biplane angiography.
The apparatus includes a biplane angiographic unit, an IVUS imaging
unit, a data fusion unit, and a display unit. The IVUS imaging unit
includes a catheter. The data fusion unit includes a 3-D pullback
path determination unit, a catheter twist determination unit, a
correlation unit, an interpolation unit, and a phase correlation
unit. The biplane angiographic unit and the IVUS imaging unit are
connected to the data fusion unit. The display unit is connected to
the data fusion unit.
[0014] The method includes the steps of initialization, image
acquisition, centerline reconstruction, IVUS segmentation, data
fusion and evaluation. The data fusion step includes the steps of
catheter detection in 3-D, reconstruction of the 3-D pullback path,
calculation of catheter twist, mapping, interpolation and rendering
a quantitative analysis.
[0015] The biplane angiographic unit is calibrated in the
initialization step. Image acquisition is performed by the biplane
angiographic unit that acquires angiograms of the tortuous vessel,
and the IVUS imaging unit that acquires IVUS images via catheter
pullback from the tortuous vessel. The phase correlation unit uses
the heart beat or the breathing cycle of the patient to ensure that
the images acquired from the IVUS catheter are obtained under
consistent conditions. The centerline of the vessel is
reconstructed from a biplane angiogram. The acquired IVUS pullback
images are then segmented. In the data fusion step, data fusion
between biplane angiography and an IVUS pullback imaging is
employed. Catheter detection in 3-D is performed using 3-D data
derived from angiographic projection images. The 3-D pullback path
determination unit determines a pullback path of the catheter from
the acquired biplane angiograms, by employing a spline-based 3-D
minimization approach.
[0016] The catheter twist determination unit determines a
tortuosity-induced twist of the catheter. The correlation
determination unit maps the captured IVUS image slices to the 3-D
pullback path, according to a pullback speed and the determined
tortuosity-induced twist. In the interpolation step, the centerline
is approximated by Bezier curves. Borders between consecutive 2-D
IVUS slices are interpolated and the IVUS slices are swept along
Bezier-approximated vessel centerlines in order to generate the 3-D
vessel reconstruction. The display unit displays quantitative
representations of the IVUS images, angiograms and 3-D
representations of the vessel.
[0017] US Patent Application Publication No. US 2006/0058647 A1 to
Strommer et al., entitled "Method and System for Delivering a
Medical Device to a Selected Position within a Lumen" is directed
to a system and method employing graphically assisted medical
positioning and imaging, for positioning a medical device within a
lumen of the body of a patient.
[0018] The system includes a medical positioning system (MPS), an
MPS catheter, two-dimensional image acquisition devices, a
graphical user interface (GUI), and a processor. The catheter
includes an MPS sensor at its tip. The processor is coupled with
the GUI and with the MPS.
[0019] A stent which is to be deployed within the lumen is coupled
with the catheter. An operator visually navigates the medical
device by maneuvering it through the lumen toward a selected
position. The position of the moving catheter within the lumen, as
determined by the MPS, is associated with a three-dimensional
coordinate system and is further associated with a respective
activity state of an organ of the patient. IVUS images are acquired
during the pull-back of the catheter from within the lumen. The
lumen is externally imaged by a two-dimensional image acquisition
device. The processor reconstructs three-dimensional images from
the two-dimensional images acquired by the two-dimensional image
acquisition device according to the organ timing signal of the
organ. The trajectory of the catheter, detected by the MPS is
superimposed on the three-dimensional images. The GUI displays a
representation of the medical device on the three-dimensional image
of the lumen.
[0020] An article by Slager, Cornelius J. et al. "True
3-Dimensional Reconstruction of Coronary Arteries in Patients by
Fusion of Angiography and IVUS (ANGUS) and Its Quantitative
Validation." Circulation Journal of the American Heart Association
102 (2000): 511-516 is directed to a method for three-dimensional
image reconstruction of coronary arteries by fusing angiographic
and IVUS information. The method employs two imaging modalities:
IVUS, which generates IVUS image cross sections and X-ray, which
generates X-ray images. The method employs a motorized stepped
pullback of a sheath-based catheter in order to acquire IVUS
images, during an R-wave-triggered mode in a cardiac cycle. The
method includes the steps of acquisition of a set of biplane
angiographic (i.e., X-ray) images, acquisition of IVUS images,
processing of X-ray and ultrasound images, 3-D reconstruction of a
catheter centerline (i.e., coreline), and repositioning of the IVUS
image cross sections on a reconstructed pullback trajectory. The
method employs a wire model and a gutter model. Both the wire model
and the gutter model estimate the length of the 3-D reconstructed
catheter centerline.
[0021] The processing of the X-ray images includes the step of 3-D
reconstruction of the catheter centerline and determining the
borders of the lumen. The processing of the ultrasound images
includes the step of determining the borders in the IVUS images, by
employing a contour detection program. The 3-D reconstruction of
the catheter centerline entails firstly, the direct 3-D
reconstruction of the distal and proximal points of the centerline.
Secondly, the centerline reconstruction between the distal and
proximal points is approximated by employing a 3-D circular
segment, which is adapted three dimensionally in a stepwise manner.
The acquired set of biplane angiographic images record the 3-D
position of the catheter and a 3-D pullback trajectory is
consequently predicted.
[0022] Contours of the lumen obtained from the IVUS images are
fused with the 3-D pullback trajectory of the catheter. Based on
the reconstructed catheter centerline, the IVUS image cross
sections are positioned on a reconstructed trajectory. The acquired
IVUS image cross sections are distributed at equidistant intervals
on the reconstructed catheter centerline and an angular rotation of
the reconstructed IVUS image cross sections is determined. The
reconstruction further entails the IVUS image cross sections to be
angularly rotated around the 3-D pullback trajectory. The acquired
biplane images are employed in optimization of the angular rotation
of the reconstructed IVUS image cross sections. The pullback length
which is determined according to the quantity of pullback steps is
compared with the reconstructed path length, which is determined
according to the wire model and the gutter model.
SUMMARY OF THE DISCLOSED TECHNIQUE
[0023] It is an object of the disclosed technique to provide a
novel method and system for determining the current position of a
selected portion (e.g., the tip) of a medical catheter within a
tubular organ, according to the current distance traversed by the
selected portion of the medical catheter from an initial position
(e.g., an origin) of a path, previously traversed by a mapping
catheter.
[0024] In accordance with the disclosed technique, there is thus
provided a method for determining the current position of a
selected portion of a medical catheter, inserted into a tubular
organ of the body of a patient. The method includes the procedures
of inserting a medical positioning system (MPS) catheter into the
tubular organ where the MPS catheter includes an MPS sensor coupled
with an MPS, acquiring a plurality of mapping positions within the
tubular organ by the MPS, displaying a mapping position
representation of the mapping positions superimposed on a
pre-operational image of the tubular organ, constructing a mapping
path according to the mapping positions where a selected one of
these mapping positions is defined as an initial position of the
mapping path, inserting the medical catheter into the tubular organ
until the selected portion reaches the initial position, displaying
an operational image of the tubular organ superimposed on the
operational image such that the operational image includes a marker
image of the tip of the medical catheter, a path representation of
the mapping path, and an initial position representation of the
initial position, registering the selected portion with the initial
position, measuring a traveled length of the medical catheter
within the tubular organ from the initial position, and estimating
the current position according to the traveled length, the mapping
positions, and according to a plurality of calculated distances
between each of the mapping positions and the initial position,
along the mapping path.
[0025] According to another aspect of the disclosed technique,
there is thus provided a system for determining the position of the
medical catheter within the tubular organ of the body of the
patient. The system includes an MPS, an MPS catheter, a memory, a
registerer, a traveled length detector, and a processor. The MPS
includes at least one electromagnetic field generator, an MPS
sensor, and an MPS processor. The MPS processor is coupled with at
least one electromagnetic field generator, the memory, and with the
MPS sensor. The MPS catheter is coupled with the MPS sensor. The
processor is coupled with the memory, the registerer and with the
traveled length detector. The traveled length detector is coupled
with the medical catheter. The electromagnetic field generator
generates an electromagnetic field. The MPS processor determines
the relative position of the MPS sensor from at least one
electromagnetic field generator, according to the electromagnetic
field. The MPS catheter is inserted into the tubular organ to a
plurality of physical points, for which the MPS processor
determines respective mapping positions thereby defining a mapping
path. One of the mapping positions is determined to be the initial
position. The memory stores the mapping path. The register
determines a registration situation of the selected portion of the
medical catheter with the initial position. The traveled length
detector measures the traveled length of the medical catheter
within the tubular organ. The traveled length is defined as a
length of the mapping path of the selected portion of the medical
catheter, from the initial position. The processor estimates the
current position of the selected portion of the medical catheter,
according to the traveled length and according to calculated
distance between the mapping positions, from the initial position
along the mapping path.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The disclosed technique will be understood and appreciated
more fully from the following detailed description taken in
conjunction with the drawings in which:
[0027] FIG. 1A is a schematic illustration of a system for
producing a mapping path of a trajectory of an MPS catheter, within
a tubular organ of the body of a patient, constructed and operative
in accordance with an embodiment of the disclosed technique;
[0028] FIG. 1B is a schematic illustration of a superimposition of
the mapping path of the trajectory of the MPS catheter of FIG. 1A,
on an image of the tubular organ;
[0029] FIG. 2A is a schematic illustration of a system for
determining the position of a medical catheter, within a tubular
organ of a patient, constructed and operative in accordance with
another embodiment of the disclosed technique;
[0030] FIG. 2B is a schematic illustration of the mapping path of
the trajectory of the MPS catheter of the system of FIG. 1A,
superimposed on an image of the tubular organ of the patient;
[0031] FIG. 3 is a schematic illustration of a method for operating
the systems of FIGS. 1A, 1B, 2A, and 2B, operative in accordance
with a further embodiment of the disclosed technique;
[0032] FIG. 4A is a schematic illustration of a system for
producing a multi-state mapping path of a trajectory of an MPS
catheter, within a tubular organ of the body of a patient,
constructed and operative in accordance with another embodiment of
the disclosed technique;
[0033] FIG. 4B is a schematic illustration of an organ timing
signal of an organ of a patient and representative points in the
organ timing signal;
[0034] FIG. 4C is a schematic illustration of a superimposition of
the multi-state mapping path of the trajectory of the MPS catheter
of FIG. 4A, on a plurality of pre-operational images;
[0035] FIG. 5A is a schematic illustration of a system for
determining the position of the tip of a medical catheter, within a
tubular organ of the body of a patient, constructed and operative
in accordance with a further embodiment of the disclosed
technique;
[0036] FIG. 5B is a schematic illustration of a multi-state mapping
path of a trajectory of the MPS catheter of the system of FIG. 5A,
superimposed on a operational image of the tubular organ of the
patient;
[0037] FIG. 6A is a schematic illustration of a method for
operating the systems of FIGS. 4A, 4B, 4C 5A, and 5B, operative in
accordance with another embodiment of the disclosed technique;
and
[0038] FIG. 6B is a schematic illustration of a continuation of the
method of FIG. 6A.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0039] The disclosed technique overcomes the disadvantages of the
prior art by employing a mapping catheter to map a path, traversed
by the mapping catheter within a tubular organ, and registering a
representation of the tip of a medical catheter with the origin of
the path. Furthermore, the disclosed technique provides a system
and method for determining the position of a selected portion
(e.g., the tip) of the medical catheter within the tubular organ,
according to the current distance of the tip of the medical
catheter from an initial position (e.g., an origin) of the path.
The mapping catheter includes an electromagnetic sensor located at
the tip thereof, to detect the position of the tip along the path,
with the aid of a Medical Positioning System (MPS). A processor
superimposes a representation of the tip of the mapping catheter,
on a two-dimensional image of the tubular organ, as a user (e.g., a
surgeon, a medical practitioner, a technician) advances the mapping
catheter within the tubular organ, to enable the user to navigate
the mapping catheter through the tubular organ.
[0040] The processor constructs a mapping path of the path of the
mapping catheter, according to different positions (i.e., mapping
positions) of the tip of the mapping catheter along the path, and
superimposes this mapping path on the two-dimensional image. At the
commencement of the operation on a patient, the user registers the
tip of the medical catheter with the origin of the mapping path.
During the operation (e.g., a surgical procedure) on the patient,
as the surgeon navigates the medical catheter within the tubular
organ, a traveled length detector measures the traveled length of
the tip of the medical catheter from the origin of the mapping
path. The processor estimates the current position of the tip of
the medical catheter, according to the traveled length of the tip
of the catheter from the origin and according to a plurality of
calculated distances between each of the mapping positions and the
initial position, along the mapping path.
[0041] The processor can gate (i.e., synchronize) each of the
mapping positions along the mapping path, with an activity state of
an organ of the patient (e.g., the heart or the lungs), and produce
a different mapping path corresponding to a different activity
state of the organ. The processor can then direct a display to
display the respective mapping path, according to the current
activity state of the organ, by employing an organ timing monitor,
such as an electrocardiogram (ECG), and the like. In this manner,
the surgeon obtains a substantially stable image of the mapping
path, against a real-time two-dimensional image of the tubular
organ. Alternatively, the processor can superimpose the mapping
path on a non-real-time image (i.e., a previously acquired image)
of the tubular organ (e.g., a cine-loop), and direct the display to
display the mapping path on this cine-loop.
[0042] The term "position" herein below, refers to the location of
a point or point-like entity in space, the orientation of the
point-like entity in space, or a combination thereof. The term
"tubular organ" herein below, refers to a bodily organ, having an
elongated tubular shape, such as a blood vessel, a vein, an artery,
a heart cavity, (e.g., atrium or chamber), a substantially tubular
or cylindrical object with non-zero internal volume, and the like.
It is noted that the terms tubular organ, tubular organ, blood
vessel, and artery, in the description herein below, are
interchangeable.
[0043] The term "organ timing signal" herein below, refers to a
signal representing the cardiac cycle of the heart of the patient,
or a signal representing the respiratory cycle of the lungs of the
patient. An organ timing signal can be acquired for example, by
employing an ECG, or measuring the movements of the tubular organ
due to cardiac or respiratory cycles, by an electromagnetic sensor.
The term "cine-loop" herein below, refers to a prerecorded sequence
of a set of two-dimensional images of the tubular organ, which are
played back repetitiously (i.e., in a loop), in synchrony with the
real-time organ timing signal of the inspected organ of the
patient. It is noted that the terms "initial position" and "origin"
are interchangeable throughout the description.
[0044] Reference is now made to FIGS. 1A and 1B. FIG. 1A is a
schematic illustration of a system, generally referenced 100, for
producing a mapping path of a trajectory of an MPS catheter, within
a tubular organ of the body of a patient, constructed and operative
in accordance with an embodiment of the disclosed technique. FIG.
1B is a schematic illustration of a superimposition of the mapping
path of the trajectory of the MPS catheter of FIG. 1A, on an image
of the tubular organ.
[0045] System 100 includes a Medical Positioning System (MPS) 102,
a processor 104, an imager 106, a pointing device 108, a display
110, an MPS catheter 112, an MPS sensor 114 and a memory (not
shown). MPS sensor 114 is located at a distal portion 116 of MPS
catheter 112 (i.e., typically attached thereto). MPS 102 includes
an electromagnetic field generator (not shown) for generating an
electromagnetic field (not shown). It is noted that MPS 102
typically employs a plurality of electromagnetic field generators
(not shown). MPS 102 further includes an MPS processor (not shown).
Processor 104 is coupled with MPS 102, imager 106, pointing device
108, display 110 and with the memory. MPS 102 is coupled with MPS
sensor 114, via an electric conductor. Alternatively, MPS 102 is
coupled with MPS sensor 114 via a wireless link. The MPS processor
is coupled with the plurality of electromagnetic field generators
and with MPS sensor 114. MPS sensor 114 is in form of a coil, which
produces an output in response to the electromagnetic field
generated by the electromagnetic field generator. MPS 102 is a
device which determines the position of distal portion 116 of MPS
catheter 112, according to the output of MPS sensor 114. The MPS
processor determines the relative position of MPS sensor 114 from
the plurality of electromagnetic field generators, according to the
electromagnetic field that is generated by each respective
electromagnetic field generator.
[0046] Imager 106 acquires a pre-operative image 150 (FIG. 1B), of
a tubular organ 118 of the body of a patient (not shown). Imager
106 is a two-dimensional image acquisition device, such as a
fluoroscope, an ultrasound image detector, a C-arm, and the like.
Alternatively, imager 106 is a three-dimensional image acquisition
device, such as computer tomography (CT) imager, magnetic resonance
imager (MRI), positron emission tomography (PET) imager, single
photon emission computer tomography (SPECT) imager, ultrasound
image detector, infrared image detector, X-ray imager, optical
coherence tomography (OCT) imager, intracardiac echocardiogram
(ICE), and the like. Pointing device 108 is a registerer, employed
for determining a registration situation, and is typically a user
interface, which can be for example, a computer mouse, a touch
screen, a track-ball, and the like.
[0047] A three-dimensional coordinate system 126 (FIG. 1B)
associated with MPS 102 is registered with a two-dimensional
coordinate system 156 associated with pre-operational image 150.
Alternatively, three-dimensional coordinate system 126 associated
with registered with a two-dimensional coordinate system (not
shown) associated with imager 106. During a mapping session (i.e.,
a pre-operational procedure), prior to an operation on the patient,
a surgeon (not shown) inserts MPS catheter 112 into tubular organ
118, until distal portion 114 of MPS catheter 112 enters a field of
view (i.e., FOV) of imager 106.
[0048] As the surgeon advances MPS catheter 112 into tubular organ
118, MPS 102 detects the position of distal portion 116 of MPS
catheter 112, according to an output of MPS sensor 114. MPS 102
acquires a plurality of mapping positions 120 (FIG. 1B), respective
of the positions of distal portion 116, during movement of MPS
catheter 112 within tubular organ 118, toward a region of interest
within the body of the patient. Alternatively, MPS 102 acquires
mapping positions 120 during pull-back of MPS catheter 112, from
the region of interest toward a point of entry (not shown) of MPS
catheter 112 into tubular organ 118. MPS 102 registers each of
mapping positions 120 with pre-operational image 150, such that
each of mapping positions 120 is associated with a respective
two-dimensional coordinate on pre-operational image 150.
[0049] Processor 104 constructs a mapping path 122 (i.e., an MPS
trace), which is an approximate representation of the trajectory of
the movement of MPS catheter 112, within tubular organ 118.
Processor 104 constructs mapping path 122, according to the
coordinates of each of mapping positions 120. The memory stores
mapping path 122.
[0050] The surgeon determines an origin 124 (FIG. 1B) of mapping
path 122. Origin 124 is a reference point, which can be for
example, a point on mapping path 122, one of mapping positions 120,
a physical point on the body of the patient (e.g., as marked by the
surgeon), and the like. The surgeon selects origin 124 by employing
pointing device 108. Processor 104 superimposes mapping path 122 on
pre-operational image 150, thereby producing a superimposed
pre-operational image 170. The registration between coordinate
system 126 associated with MPS 102 and coordinate system 156
associated with pre-operational image 150 facilitates this
superposition. Processor 104 directs display 110 to display
superimposed pre-operational image 170.
[0051] Reference is now made to FIGS. 2A and 2B. FIG. 2A is a
schematic illustration of a system, generally referenced 200, for
determining the position of a medical catheter, within a tubular
organ of a patient, constructed and operative in accordance with
another embodiment of the disclosed technique. FIG. 2B is a
schematic illustration of the mapping path of the trajectory of the
MPS catheter of the system of FIG. 1A, superimposed on an image of
the tubular organ of the patient.
[0052] System 200 includes a traveled length detector 202, a
processor 204, an imager 206, a pointing device 208, a display 210,
a medical catheter 212, a radiopaque marker 214, a memory (not
shown), and an Intravascular Ultrasound (IVUS) imager 220.
Radiopaque marker 214 and IVUS imager 220 are located at a distal
portion 216 of medical catheter 212. Processor 204 is coupled with
traveled length detector 202, imager 206, pointing device 208,
display 210, and with the memory. Traveled length detector 202 is
coupled with medical catheter 212. Processor 204, imager 206,
pointing device 208, and display 210, are similar to processor 104,
imager 106, pointing device 108, and display 110, respectively.
Alternatively, processor 204, imager 206, pointing device 208, and
display 210, are different than processor 104, imager 106, pointing
device 108, and display 110, respectively.
[0053] Traveled length detector 202 is a device which measures the
travel distance of medical catheter 212, relative to a selected
point. Traveled length detector 202 can be for example, a
fiber-optic interferometric system, electromechanical system
utilizing an electric generator, variable electro-resistive device
(e.g., a linear potentiometer, rotary potentiometer), and the
like.
[0054] During operation on the body of the patient, the surgeon
inserts medical catheter 212 into tubular organ 218 (i.e., after
MPS catheter 112 is removed from tubular organ 218), until
radiopaque marker 214 of medical catheter 212 is located within the
FOV of imager 206. With reference to FIG. 2B, the surgeon advances
medical catheter 212 into tubular organ 118, and imager 206
acquires an operational image 250 of tubular organ 118, until
radiopaque marker 214 reaches origin 124. Three-dimensional
coordinate system 126 associated with MPS 102 is registered with a
two-dimensional coordinate system 256 associated with operational
image 250. Alternatively, three-dimensional coordinate system 126
is registered with a two-dimensional coordinate system (not shown)
associated with imager 206. Processor 204 superimposes mapping path
122 on operational image 250, thereby producing a superimposed
operational image 270. Processor 204 directs display 210 to display
superimposed operational image 270.
[0055] Radiopaque marker 214 is made of a material (e.g., barium
sulfate, metal), which is opaque to an imaging medium employed by
imager 206, such as sound waves, electromagnetic waves (e.g.,
X-ray), and the like. Therefore, radiopaque marker 214 is visible
in operational image 250. The surgeon can observe an image 252 of
radiopaque marker 214 within operational image 250, and within
superimposed operational image 270.
[0056] When radiopaque marker 214 reaches origin 124, the surgeon
may input a reset command to processor 204, via pointing device
208, to reset a distance of travel (not shown) measured by traveled
length detector 202. The surgeon advances medical catheter 212
within tubular organ 118, substantially along mapping path 122
toward a region of interest (not shown) of the body of the patient.
Traveled length detector 202 measures and outputs the distance
traveled by medical catheter 212, within tubular organ 118 relative
to origin 124. It is noted, that processor 204 may correct the
output (i.e., the distance measurement) of traveled length detector
202 whenever the path of medical catheter 212 deviates from the
path of mapping path 122 (i.e., by fault of the surgeon or of other
factors) by compensation methods known in the art.
[0057] As the surgeon advances medical catheter 212 within tubular
organ 118, processor 204 estimates a current position of distal
portion 216 within tubular organ 212, according to the output of
traveled length detector 202, and according to calculated distances
between mapping positions 120 (FIG. 1B) from origin 124, along
mapping path 122. Processor 204 superimposes a representation of
previous positions 280, on superimposed operational image 270 and
directs display 210 to display superimposed operational image
270.
[0058] IVUS imager 220 acquires one or more images (not shown) of
an inner wall (not shown) of tubular organ 118, during a forward
movement of medical catheter 212 from the point of entry of medical
catheter 212 into the body of the patient, toward the region of
interest. Alternatively, IVUS imager 220 acquires the images during
pull-back of medical catheter 212 from the region of interest,
toward the point of entry of medical catheter 212 into the body of
the patient.
[0059] Reference is now made to FIG. 3, which is a schematic
illustration of a method for operating the systems of FIGS. 1A, 1B,
2A, and 2B, operative in accordance with a further embodiment of
the disclosed technique. In procedure 302, an MPS catheter is
inserted into the tubular organ, the MPS catheter including an MPS
sensor associated with an MPS. With reference to FIGS. 1A and 1B,
MPS catheter 112 is inserted into tubular organ 118. MPS catheter
112 includes an MPS sensor 114 at distal portion 116 of MPS
catheter 112. MPS sensor 114 is associated with MPS 102.
[0060] In procedure 304, a pre-operational image of the tubular
organ of the body of a patient is acquired by an imager. With
reference to FIGS. 1A and 1B, imager 106 acquires pre-operational
image 150 of tubular organ 118.
[0061] In procedure 306, a plurality of mapping positions are
acquired by the MPS, according to an output of the MPS sensor. With
reference to FIGS. 1A and 1B, MPS sensor 114 acquires mapping
positions 120, respective of the respective position of distal
portion 116.
[0062] In procedure 308, a plurality of mapping position
representations of the respective mapping positions are
superimposed on the pre-operational image. With reference to FIGS.
1A, and 1B, processor 104 superimposes mapping positions 120 on
operational image 150 (not shown), thereby producing superimposed
operational image 170.
[0063] In procedure 310, a mapping path is constructed according to
mapping positions, whereby a selected one of the mapping positions
is defined as an initial position (i.e., an origin) of the mapping
path. With reference to FIGS. 1A and 1B, MPS 102 determines the
position of each of mapping positions 120, and processor 104
constructs mapping path 112 of the trajectory of distal portion 116
of MPS catheter 112, within tubular organ 118. The surgeon
determines the initial position 124 of mapping path 122 by
employing pointing device 108.
[0064] In procedure 312 the MPS catheter is removed from the
tubular organ. With reference to FIG. 1A, the surgeon removes MPS
catheter 112 from tubular organ 118.
[0065] In procedure 314, an operational image of the tubular organ
is acquired. With reference to FIGS. 2A and 2B, imager 206 acquires
operational image 250 of tubular organ 118. It is noted that in an
intermediate procedure (not shown), which can follow procedure 314,
the operational image 250 is registered with pre-operational image
150.
[0066] It is further noted, that the following procedures (i.e.,
procedure 316 and procedure 318) may typically be executed
simultaneously. In procedure 316, a medical catheter is inserted
into the tubular organ, until the selected portion of the medical
catheter reaches the initial position. With reference to FIGS. 2A
and 2B, the surgeon inserts medical catheter 212 into tubular organ
118, until the selected portion (e.g., marked by radiopaque marker
214) reaches initial position 124 by viewing image 252 of
radiopaque marker 214 on superimposed operational image 270.
[0067] In procedure 318, a path representation of the mapping path,
and an initial position representation of the initial position are
displayed, superimposed on the operational image of the tubular
organ, the operational image including a marker image of the tip of
the medical catheter. With reference to FIGS. 2A and 2B, display
210 displays superimposed operational image 270. Superimposed
operation image 270 includes illustrates a path representation of
mapping path 122, an initial position representation of initial
position 124, and marker image 252 of radiopaque marker 214.
[0068] In procedure 320, the selected portion (e.g., the tip) of
the medical catheter is registered with the initial position. With
reference to FIGS. 2A and 2B, the surgeon registers via pointing
device 208 the selected portion (e.g., radiopaque marker 214) with
initial position 124.
[0069] In procedure 322, the traveled length of the medical
catheter within the tubular organ is measured from the initial
position. With reference to FIGS. 2A and 2B, traveled length
detector 202 measures and outputs the traveled length of medical
catheter 212 within tubular organ 118, relative to initial position
124.
[0070] In procedure 324, the current position of the selected
portion of the medical catheter is estimated, according to the
traveled length, the mapping positions, and according to the
plurality of calculated distances between each of the mapping
positions and the initial position along the mapping path. With
reference to FIGS. 2A and 2B, processor 204 determines an estimate
of the current position of the selected portion (e.g., distal
portion 216), according to the output of traveled length detector
202, and according to mapping positions 120 (FIG. 1B). Processor
204 superimposes previous position 280 of distal portion 216, on
superimposed operational image 270. Processor 204 directs display
210 to display superimposed operational image 270.
[0071] According to another aspect of the disclosed technique, the
system further includes an organ monitor coupled with the
processor. The organ monitor acquires an organ timing signal of an
organ of the patient. The processor gates the image acquired by the
imager (e.g., a real-time image, a cine-loop), with the respective
organ timing signal of the organ. The display displays a
representation of the current position as well as previous
positions of a selected portion (e.g., the distal portion or the
tip) of the medical catheter, on the respective operational image,
associated with the respective organ timing signal. In this manner,
the surgeon can observe the representation of the tip of the
medical catheter on an image of the tubular organ, which
corresponds to the current position of the tip, respective of the
current activity state of the organ. The organ monitor can monitor
the timing signals of different organs of the body of the patient,
which can cause the tubular organ in the respective organ such as
the heart, lungs, and the like, to move in the corresponding
cycles.
[0072] Reference is now made to FIGS. 4A, 4B and 4C. FIG. 4A is a
schematic illustration of a system, generally referenced 400, for
producing a multi-state mapping path of a trajectory of an MPS
catheter, within a tubular organ of the body of a patient,
constructed and operative in accordance with another embodiment of
the disclosed technique. FIG. 4B is a schematic illustration of an
organ timing signal of an organ of a patient and representative
points in the organ timing signal. FIG. 4C is a schematic
illustration of a superimposition of the multi-state mapping path
of the trajectory of the MPS catheter of FIG. 4A, on a plurality of
pre-operational images.
[0073] System 400 includes an MPS 402, a processor 404, an imager
406, a pointing device 408, a display 410, an MPS catheter 412, an
MPS sensor 414, memory (not shown), and an organ monitor 430. MPS
sensor 414 is located at a distal portion 416 of MPS catheter 412.
Processor 404 is coupled with MPS 402, imager 406, pointing device
408, display 410, organ monitor 430, and with the memory. MPS 402
is coupled with MPS sensor 414, via an electric conductor.
Alternatively, MPS 402 is coupled with MPS sensor 414, via a
wireless link.
[0074] Organ monitor 430 is a device which acquires an organ timing
signal 440 (FIG. 4B) of the organ of the patient (i.e., a signal
representing the activity state of the organ, such as phases or
states of the heart). Organ monitor 430 can be an electrocardiogram
(ECG), a pulse monitor, a respiration monitor, and the like.
[0075] Imager 406 acquires a plurality of pre-operational images
4501, 4502, and 450N (FIG. 4C) of a tubular organ 418. Each of
pre-operational images 4501, 4502, and 450N is associated with
respective points 4421 (FIG. 4B), 4422, and 442N in a cycle of
organ timing signal 440. Pre-operational image 4501 is associated
with point 4421 in the cycle of organ timing signal 440.
Pre-operational image 4502 is associated with point 4422 in the
cycle of organ timing signal 440. Pre-operational image 450N is
associated with point 440N in the cycle of organ timing signal 440.
Alternatively, imager 406 acquires a single real-time
pre-operational image (not shown). It is noted that tubular organ
418 (FIG. 4A) is depicted by multiple representations thereof,
which represent the movement of tubular organ 418 during the
various states of the organ cycle.
[0076] A three-dimensional coordinate system 466 associated with
MPS 402 is registered with a two-dimensional coordinate system 456
associated with each of pre-operational images 4501, 4502, and
450N. Alternatively, three-dimensional coordinate system 466 is
registered with a two-dimensional coordinate system (not shown)
associated with imager 406. During a mapping session, prior to a
medical operation on the body of the patient, a surgeon (not shown)
inserts MPS catheter 412 into tubular organ 418, until distal
portion 414 of MPS catheter 412 enters an FOV of imager 406.
[0077] As the surgeon advances MPS catheter 412 into tubular organ
418, MPS 402 detects the position of MPS sensor 414, located
substantially at a distal portion 416 of MPS catheter 412,
according to an output of MPS sensor 414. MPS 402 acquires a
plurality of mapping positions 4601, 4602, and 460N (FIG. 4C),
respective of the position of distal portion 416, during a forward
movement of MPS catheter 412, from the point of entry (not shown)
of MPS catheter 412 toward the region of interest. Alternatively,
MPS 402 acquires mapping positions 4601, 4602 and 460N during
pull-back of MPS catheter 412, from the region of interest toward
the point of entry. Mapping positions 4601, 4602 and 460N are
classified into groups of mapping positions, each group of mapping
positions being associated with a specific point in the cycle of
the organ timing signal. A plurality of mapping positions 4601
belong to a group 1 (FIGS. 4B and 4C) associated with point 4421 in
organ timing signal 440. A plurality of mapping positions 4602
belong to a group 2 (FIGS. 4B and 4C) associated with point 4422 in
organ timing signal 440. A plurality of mapping positions 460N
belong to a group N (FIGS. 4B and 4C) associated with point 442N in
organ timing signal 440. Each mapping position in a particular
group of mapping positions is acquired at the same point in the
cycle of organ timing signal 440. For example, each mapping
position 4601 is acquired at the same point 4421, in the cycle of
organ timing signal 440, (i.e., once the cycle repeats, in a
repetitive cyclic organ timing signal, the next mapping position is
acquired).
[0078] MPS 402 registers each mapping position in a particular
group of mapping positions with respective two-dimensional
coordinates in the respective pre-operational image. For example,
MPS 402 registers each mapping position of mapping positions 4601
with respective two-dimensional coordinates in pre-operational
image 4501.
[0079] Mapping positions 4601, 4602, and 460N define a multi-state
mapping path similar to mapping path 122 (FIG. 2B). Each group of
mapping positions defines a mapping path of the multi-state mapping
path, corresponding to the respective point in the organ timing
signal of the organ. Processor 402 produces a mapping path 4621
from mapping positions 4601. Mapping path 4621 is an approximate
representation of the trajectory (not shown) of the movement of
distal portion 416 of distal portion 416 of MPS catheter 412,
within tubular organ 418, at point 4421 in the cycle of organ
timing signal 440. Processor 402 produces a mapping path 4622 from
mapping positions 4602. Mapping path 4622 is an approximate
representation of the trajectory (not shown) of the movement of
distal portion 416 of MPS catheter 412, within tubular organ 418,
at point 4422 in the cycle of organ timing signal 440. Processor
402 produces a mapping path 462N from mapping positions 460N.
Mapping path 462N is an approximate representation of the
trajectory (not shown) of the movement of distal portion 416 of MPS
catheter 412, within tubular organ 418, at point 442N in the cycle
of organ timing signal 440. The memory stores mapping paths 4621,
4622, and 462N.
[0080] The surgeon determines a single initial position (not shown)
of all of mapping paths 4621, 4622, and 462N, typically one of
mapping positions 4601, 4602, and 460N, or alternatively, a
physical point on the body of the patient, and the like. Further
alternatively, the surgeon can determine a plurality of origins
4641, 4642, and 464N (FIG. 4C) of the respective mapping paths
4621, 4622, and 462N. Each of origins 4641, 4642, and 464N are
reference points, which can be for example, points on respective
mapping paths 4621, 4622, and 462N, one of respective mapping
positions 4601, 4602, and 460N, a physical point on the body of the
patient (e.g., marked by the surgeon), and the like. Each origin
4641, 4642 and 464N is associated with the respective point in the
cycle of organ timing signal 440. For example, origin 4641 is
associated with point 4421 within the cycle of organ timing signal
440. Alternatively, each origin 4641, 4642, and 464N is associated,
respectively, with mapping paths 4621, 4622, and 462N. The surgeon
selects the initial position, or alternatively, origins 4641, 4642,
and 464N, by employing pointing device 408 (FIG. 4A).
[0081] Processor 404 superimposes mapping path 4621 on
pre-operational image 4501, thereby producing a superimposed
pre-operational image 4701. Processor 404 superimposes mapping path
4622 on pre-operational image 4502, thereby producing a
superimposed pre-operational image 4702. Processor 404 superimposes
mapping path 462N on pre-operational image 450N, thereby producing
a superimposed pre-operational image 470N. Display 410 displays
superimposed pre-operational images 4701, 4702, and 470N.
Superimposed pre-operational images 4701, 4702, and 470N are
synchronized (i.e., gated) with organ timing signal 440, and are
displayed on display 410 at a display rate, which is substantially
equal or greater than the cycle time of organ timing signal 440,
unless imager 406 acquires all except one of pre-operational images
4501, 4502, and 450N at some point in the phase of the organ which
is aperiodic, due to abnormal rhythms of the organ (e.g.,
arrhythmia in the heart).
[0082] Reference is now made to FIGS. 4B, 5A and 5B. FIG. 5A is a
schematic illustration of a system, generally referenced 500, for
determining the position of the tip of a medical catheter, within a
tubular organ of the body of a patient, constructed and operative
in accordance with a further embodiment of the disclosed technique.
FIG. 5B is a schematic illustration of a multi-state mapping path
of a trajectory of the MPS catheter of the system of FIG. 5A,
superimposed on an operational image of the tubular organ of the
patient.
[0083] System 500 includes a traveled length detector 502, a
processor 504, an imager 506, a pointing device 508, a display 510,
a medical catheter 512, a radiopaque marker 514, an IVUS imager
520, a memory (not shown), and an organ monitor 530. Radiopaque
marker 514 and IVUS imager 520 are located substantially at a
distal portion 516 of medical catheter 512. Processor 504 is
coupled with traveled length detector 502, imager 506, pointing
device 508, display 510, organ monitor 530, and with the memory.
Traveled length detector 502 is coupled with medical catheter 512.
Traveled length detector 502, processor 504, imager 506, pointing
device 508, and display 510, are similar to traveled length
detector 202 (FIG. 2A), processor 404 (FIG. 4A), imager 406,
pointing device 408, and display 410, respectively.
[0084] During medical operation on the body of the patient, the
surgeon inserts medical catheter 512 into tubular organ 418, until
radiopaque marker 514 of medical catheter 512 is within the FOV of
imager 506. The surgeon advances medical catheter 512 into tubular
organ 418, and imager 506 acquires a plurality of operational
images 5501, 5502, and 550N (FIG. 5B) until radiopaque marker 514
reaches the initial position. The initial position can be one of
the mapping positions, an activity-state specific origin (i.e., one
of origins 4641, 4642, and 464N), corresponding to one of points
4421, 4422, 442N (FIG. 4B), respectively, and the like. It is noted
that each of operational images 5501, 5502, and 550N is a real-time
image of tubular organ 418. Alternatively, each of operational
images 5501, 5502, and 550N, can be an image which is previously
acquired.
[0085] Radiopaque marker 514 is made of a material that is visible
in operational images 5501, 5502, and 550N of tubular organ 418.
The surgeon can observe images 5521, 5522, and 552N of radiopaque
marker 514, in operational images 5501, 5502, and 550N (FIG. 5B),
respectively.
[0086] Operational images 5501, 5502, and 550N are associated with
points 4421, 4422, and 442N (FIG. 4B), respectively, in a cycle of
organ timing signal 440. Operational image 5501 is associated with
point 4421 in a cycle of organ timing signal 440. Operational image
5502 is associated with point 4422 in the cycle of organ timing
signal 440. Operational image 550N is associated with point 442N in
the cycle of organ timing signal 440.
[0087] A three-dimensional coordinate system 466 associated with
MPS 402 is registered with a two-dimensional coordinate system 556
associated with operational images 5501, 5502, and 550N.
Alternatively, three-dimensional coordinate system 466 is
registered with a two-dimensional coordinate system (not shown)
associated with imager 506.
[0088] Processor 504 superimposes each of mapping paths 4621, 4622,
and 462N on operational images 5501, 5502, and 550N, respectively,
thereby producing superimposed operational images 5701, 5702, and
570N, respectively. Thus, processor 504 superimposes mapping path
4621 on operational image 5501, thereby producing a superimposed
operational image 5701. Processor 504 superimposes mapping path
4622 on operational image 5502, thereby producing a superimposed
operational image 5702. Processor 504 superimposes mapping path
462N on operational image 550N, thereby producing a superimposed
operational image 570N. Display 510 displays superimposed
operational images 5701, 5702, and 570N.
[0089] When radiopaque marker 514 reaches the initial position
(i.e., an activity-state specific origin, such as one of origins
4641, 4642, and 464N), the surgeon inputs a reset command to
processor 504, by employing pointing device 508, to reset a
distance of travel (not shown) of traveled length detector 502. The
surgeon advances medical catheter 512 within tubular organ 418
substantially along a superposition (or a combination) of mapping
paths 4621, 4622, and 462N toward the region of interest of the
body of the patient. A combination of mapping paths is formed from
mapping paths 4621, 4622, and 462N corresponding to groups of
points respective of points 4421, 4422, and 442N, respectively, in
organ timing signal 440.
[0090] Traveled length detector 502 measures and outputs the travel
of medical catheter 512 within tubular organ 418 relative to the
initial position. It is noted, that processor 504 may correct the
output (i.e., the distance measurement) of traveled length detector
502 whenever the path of medical catheter 512 deviates from the
path of each MPS paths 4621, 4622, and 462N (i.e., by fault of the
surgeon or by other factors) by compensation methods known in the
art.
[0091] As the surgeon advances medical catheter 512 within tubular
organ 418, processor 504 estimates the current position (not
shown), of distal portion 516 within tubular organ 512, according
to the output of traveled length detector 502, and according to
mapping positions 5621, 5622, and 562N, respectively. Processor 504
superimposes a representation of each of previous positions 5801,
5802, and 580N, on superimposed operational images 5701, 5702, and
570N, respectively. Display 510 displays superimposed operational
images 5701, 5702, and 570N in a real-time sequenced manner. The
processor 504 can direct display 510 to display a playback of
superimposed operational images 5701, 5702, and 570N.
[0092] IVUS imager 520 acquires ultrasound images (not shown) of
the region of interest, during a forward movement of medical
catheter 512 from a point of entry of medical catheter 512 into the
body of the patient toward the region of interest. Alternatively,
IVUS imager 520 acquires the ultrasound images during pull-back of
medical catheter 512 from region of interest toward the point of
entry. Superimposed operational images 5701, 5702, and 570N are
synchronized (i.e., gated) with organ timing signal 440, and are
displayed on display 510 at a display rate, which is substantially
equal or greater than the cycle time of organ timing signal 440,
unless the surgeon acquires all except one of operational images
5501, 5502, and 550N at some point in the phase of the organ which
is aperiodic (due to abnormal rhythms of the organ, e.g.,
arrhythmia in the heart).
[0093] Reference is now made to FIGS. 6A and 6B. FIG. 6A is a
schematic illustration of a method for operating the systems of
FIGS. 4A, 4B, 4C 5A, and 5B, operative in accordance with another
embodiment of the disclosed technique. FIG. 6B is a schematic
illustration of a continuation of the method of FIG. 6A.
[0094] In procedure 602, a plurality of pre-operative images of a
tubular organ of the body of a patient are acquired by an imager.
With reference to FIGS. 4A and 4C, imager 406 acquires
pre-operational images 4501, 4502, and 450N of tubular organ 418.
Alternatively, imager 406 acquires a single real-time
pre-operational image.
[0095] In procedure 604 (FIG. 6A), the organ timing signal of the
tubular organ is acquired. With reference to FIGS. 4B and 5A, organ
monitor 530 (FIG. 5A) is coupled (not shown) with tubular organ 418
and acquires organ timing signal 440 (FIG. 4B) of tubular organ
418.
[0096] In procedure 606, the MPS catheter is inserted into the
tubular organ, the MPS catheter including an MPS sensor coupled
with an MPS. With reference to FIG. 4A, MPS catheter 412 is
inserted into tubular organ 418. MPS catheter 412 includes MPS
sensor 414, which is coupled with MPS 402.
[0097] In procedure 608, a plurality of mapping positions within
the tubular organ are acquired by the MPS according to an output of
the MPS sensor. The mapping positions are grouped into a respective
mapping position group, each mapping position group is associated
with a respective point in the cycle of the organ timing signal.
With reference to FIGS. 4A, 4B, and 4C, mapping positions 4601,
4602 and 460N (FIG. 4C) are acquired by MPS 402 (FIG. 4A) according
to the output of MPS sensor 414 (FIG. 4A). Mapping positions 4601,
4602 and 460N are grouped into respective mapping groups 4421, 4422
and 442N (FIG. 4B), whereby each mapping position group 4421, 4422
and 442N is associated with a respective point (i.e., groups 1
through N illustrated in FIG. 4B) in the cycle of organ timing
signal 440 (FIG. 4B).
[0098] In procedure 610, a plurality of mapping position
representations of the respective mapping positions are displayed,
each superimposed on a respective pre-operational image. With
reference to FIGS. 4A and 4C, mapping positions 4601, 4602 and 460N
(FIG. 4C) are displayed on display 410 (FIG. 4A) each superimposed
(not shown) on respective pre-operational images 4701, 4702 and
470N (FIG. 4C).
[0099] In procedure 612, a plurality of mapping paths are
constructed, each of the mapping paths corresponding to a
respective mapping position group. With reference to FIGS. 4A and
4C, processor 404 constructs mapping paths 4621, 4622 and 462N
(FIG. 4C), each mapping path corresponding to a respective mapping
position group (i.e., groups 1, 2, and N, respectively).
[0100] In procedure 614 the MPS catheter is removed from the
tubular organ. With reference to FIG. 4A, the surgeon removes MPS
catheter 412 from tubular organ 418.
[0101] It is noted that the following procedures (i.e., procedure
618 and procedure 620) are typically executed simultaneously. In
procedure 618, a medical catheter is inserted into the tubular
organ until a selected portion of the medical catheter reaches a
selected one of the mapping positions. The selected mapping
position corresponds to a respective mapping position group, and is
defined as an initial position. With reference to FIGS. 4C, 5A and
5B, medical catheter 512 is inserted into tubular organ 418 until
distal portion 516 (i.e., the selected portion) reaches one of
mapping positions 4601, 4602 and 460N (FIG. 4C). Alternatively,
medical catheter 512 is inserted into tubular organ 418 until
radiopaque marker 514 (FIG. 5A), located at distal portion 516
(FIG. 5A) reaches a respective one of origins 4641, 4642 and 464N
(FIG. 4C) of the respective group of mapping positions 4601, 4602
and 460N (FIG. 4C). A selected mapping position is defined as the
initial position (not shown). It is noted that that surgeon
determines when radiopaque marker 514 reaches origin according to
procedure 620.
[0102] In procedure 620, an initial position representation of the
initial position, the plurality of mapping path representations of
the mapping paths, and a plurality of marker images of the tip of
the medical catheter are displayed, each superimposed on the
respective operational image. With reference to FIGS. 5A and 5B,
representations of mapping paths 4621, 4622 and 462N (FIG. 5B) are
displayed by display 510 (FIG. 5A), each respectively superimposed
on operational images 5501, 5502 and 550N (FIG. 5B) as superimposed
operational images 5701, 5702 and 570N (FIG. 5B), respectively. A
representation of the initial position is superimposed (not shown)
on superimposed operational images 5701, 5702 and 570N. Marker
images 5521, 5522 and 552N (FIG. 5B) of radiopaque marker 514 (FIG.
5A) are each displayed on the respective one of superimposed
operational images 5701, 5702 and 570N.
[0103] It is noted that in an intermediate procedure (not shown),
which can follow procedure 620, each of operational images 5501,
5502, and 550N of tubular organ 418 are registered with each of
pre-operational images 4501, 4502, and 450N, respectively.
[0104] In procedure 622, the selected portion of the medical
catheter is registered with the initial position according to the
initial position representation and the at least one marker image.
With reference to FIGS. 5A and 5B, the surgeon employs pointing
device 508 (FIG. 5A) for selecting a registration situation,
thereby registering the selected portion (e.g., radiopaque marker
514) with the initial position, according to the initial position
representation (e.g., a selected one of origins 4641, 4642 and 464N
in FIG. 5B), according to the initial position representation and
at least one marker image (i.e., one of marker images 5521, 5522
and 552N).
[0105] In procedure 624, the traveled length of the medical
catheter within the tubular organ is measured from the initial
position. With reference to FIGS. 5A and 5B, traveled length
detector 502 measures the traveled length of medical catheter 512
within tubular organ 418 relative to the initial position, and
produces an output respective of the traveled length.
[0106] In procedure 624, the current position of the selected
portion of the medical catheter is estimated, according to the
measured travel length relative to the origin, the mapping
positions, and according to a plurality of calculated distances
between each of the mapping positions within a respective mapping
position group and the initial position. With reference to FIGS. 5A
and 5B, processor 504 estimates the current position of distal
portion 516, according to the output of traveled length detector
502, and according to the mapping positions 4601, 4602, and 460N
(FIG. 4C). Processor 504 superimposes previous positions 5801,
5802, and 580N of distal portion 516 on operational images 5501,
5502, and 550N, respectively, thereby producing superimposed
operational images 5701, 5702, and 570N, respectively. Display 510
displays superimposed operational images 5701, 5702, and 570N in a
real-time sequenced manner. Alternatively, the processor can direct
display 510 to display a playback of superimposed operational
images 5701, 5702, and 570N.
[0107] It will be appreciated by persons skilled in the art that
the disclosed technique is not limited to what has been
particularly shown and described hereinabove. Rather the scope of
the disclosed technique is defined only by the claims, which
follow.
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