U.S. patent application number 14/442427 was filed with the patent office on 2016-09-22 for integration of ultrasound and x-ray modalities.
The applicant listed for this patent is KONINKLIJKE PHILIPS N.V.. Invention is credited to Pascal Yves Francois Cathier, I, Raoul Florent, Olivier Pierre Nempont.
Application Number | 20160270758 14/442427 |
Document ID | / |
Family ID | 47429695 |
Filed Date | 2016-09-22 |
United States Patent
Application |
20160270758 |
Kind Code |
A1 |
Cathier, I; Pascal Yves Francois ;
et al. |
September 22, 2016 |
INTEGRATION OF ULTRASOUND AND X-RAY MODALITIES
Abstract
The present invention relates to image acquisition technology.
In particular, the present invention relates to tracking of an
object of interest in ultrasound image information. For
interventional procedures, an object of interest, e.g. the tool by
which a procedure is performed, is depicted in image information
acquired by a certain imaging modality. However, e.g. during
transcatheter intracardiac procedures, tools are employed, which
are rather narrow objects that may experience substantive passive
motion due to heartbeat and blood flow as well as active motion due
to the interventionist steering the tool. The present invention to
allows steering two-dimensional ultrasound image acquisition, in
particular steering of an imaging plane of an ultrasound image
acquisition device, so that an object of interest remains visible
in the acquired images, in particular without continuous
readjustment of imaging parameters. Accordingly, a method for
ultrasound image acquisition, in particular for tracking an object
of interest in ultrasound image information, is provided comprising
receiving (12) X-ray image information (40) and ultrasound image
information (42), detecting (14) an object of interest (36) in the
X-ray image information (40) and steering (16) two-dimensional
ultrasound image acquisition such that the object of interest (36)
is within a first ultrasound image plane (42).
Inventors: |
Cathier, I; Pascal Yves
Francois; (Asnieres-sur-Seine, FR) ; Nempont; Olivier
Pierre; (Suresnes, FR) ; Florent; Raoul;
(Ville D'Avray, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KONINKLIJKE PHILIPS N.V. |
Eindhoven |
|
NL |
|
|
Family ID: |
47429695 |
Appl. No.: |
14/442427 |
Filed: |
December 3, 2013 |
PCT Filed: |
December 3, 2013 |
PCT NO: |
PCT/IB2013/060582 |
371 Date: |
May 13, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 6/4441 20130101;
A61B 8/5261 20130101; A61B 6/4417 20130101; A61B 8/12 20130101;
A61B 6/4085 20130101; A61B 6/5247 20130101; A61B 8/0883 20130101;
A61B 6/12 20130101; A61B 8/0841 20130101; A61B 8/4416 20130101;
A61B 8/4483 20130101; A61B 6/461 20130101; A61B 8/54 20130101; A61B
6/54 20130101; A61B 8/461 20130101 |
International
Class: |
A61B 8/08 20060101
A61B008/08; A61B 6/00 20060101 A61B006/00; A61B 8/00 20060101
A61B008/00; A61B 6/12 20060101 A61B006/12 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 3, 2012 |
EP |
12306503.9 |
Claims
1. Method for ultrasound image acquisition, in particular for
tracking an object of interest in ultrasound image information,
comprising receiving X-ray image information and ultrasound image
information; detecting an object of interest in the X-ray image
information; and steering two-dimensional ultrasound image
acquisition such that the object of interest is within a first
ultrasound image plane; and wherein the first ultrasound image
plane comprises the X-ray source, the ultrasound source and the
projection of the object of interest in the X-ray image
information.
2. Method according to claim 1, further comprising registering the
X-ray image information and the ultrasound image information for
obtaining a spatial relation between the X-ray image information
and the ultrasound image information.
3. (canceled)
4. Method according to claim 1, further comprising visualizing the
two-dimensional ultrasound image information of the first
ultrasound image plane.
5. Method to claim 1, wherein the ultrasound source is a TEE
ultrasound source; and/or wherein the object of interest is an
interventional device.
6. Method to claim 1, further comprising obtaining second
ultrasound image information corresponding to a second ultrasound
image plane comprising the ultrasound source and the object of
interest defining a line in between such that a degree of freedom
is available for orienting the second ultrasound image plane about
the line.
7. Method to claim 1, further comprising adjusting the thickness of
at least one of the first ultrasound image plane and the second
ultrasound image plane to aid in having the object of interest is
within at least one of the respective image planes.
8. System for ultrasound image acquisition, in particular for
tracking an object of interest in ultrasound image information
comprising an X-ray system having an X-ray source and an X-ray
detector; an ultrasound system; wherein the system is adapted to
receive X-ray image information and ultrasound image information;
to detect an object of interest in the X-ray image information; and
to steer two-dimensional ultrasound image acquisition such that the
object of interest is within a first ultrasound image plane; and
wherein the first ultrasound image plane comprises the X-ray
source, the ultrasound source and the projection of the object of
interest in the X-ray image information.
9. System according to claim 8, further comprising a processing
element; a control element; and a display unit.
10. Computer-readable medium, in which a computer program for
ultrasound image acquisition, in particular for tracking an object
of interest in ultrasound image information is stored, which
computer program, when being executed by a processing element, is
adapted to carry out the method according to claim 1.
11. Program element for ultrasound image acquisition, in particular
for tracking an object of interest in ultrasound image information,
which program element, when being executed by a processing element,
is adapted to carry out the method according to claim 1.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to image acquisition
technology. In particular, the present invention relates to
tracking of an object of interest in ultrasound image information.
More particularly, the present invention relates to a method for
ultrasound image acquisition, a system for ultrasound image
acquisition, a computer-readable medium as well as a program
element for ultrasound image acquisition.
BACKGROUND OF THE INVENTION
[0002] A current trend in interventional procedures is a tighter
integration of ultrasound and X-ray modalities. In other words,
different image modalities are not employed separately but rather
conjointly during a specific procedure. Thereby, drawbacks of
certain modalities may be compensated by advantages of other
modalities.
[0003] E.g., although modern interventional ultrasound solutions
offer the possibility of 3D imaging, it is often relied upon
two-dimensional ultrasound imaging for various reasons. Amongst
those reasons may be a higher image quality, a higher frame rate
and no need for cropping, volume orientation or rendering parameter
tuning when employing two-dimensional ultrasound images versus 3D
imaging.
[0004] For interventional procedures, an object of interest, e.g.
the tool by which the procedure is performed, is depicted in the
image information acquired by the respective modalities. By
depicting said object or overlaying image information of said
object and the image information of a respective modality, a person
performing the procedure readily obtains visual information about
the location and/or orientation of the object of interest with
regard to anatomic structures shown in the modality's image
information. E.g., the path of a tool tip through tissue, may be
tracked in the respective image information, i.e. visually followed
by the person performing the procedure. Such tracking thus allows
to reconfirm the correctness of a procedure, i.e. whether the
procedure is correctly conducted.
[0005] However, during transcatheter intracardiac procedures, such
as mitral clip or arterial fibrillation ablation, transcatheter
tools being employed, e.g. a mitral clip or ablation catheter, are
rather narrow objects that may experience substantive passive
motion due to breathing, heartbeat and blood flow as well as active
motion due to the interventionist steering the tool.
[0006] In such procedures, ultrasound images are regularly acquired
by employing a transesophageal echocardiogram or TEE. The TEE is
performed by a specialized probe being inserted into a patient's
esophagus, which contains an ultrasound transducer at its tip. The
ultrasound transducer is adapted for image acquisition and Doppler
evaluation of ultrasound images. TEEs regularly provide clearer
images, especially with regard to tissue structures that are
difficult to view transthoracically, i.e. through the chest wall by
employing an external ultrasound transducer.
[0007] Since the TEE itself lies in the esophagus, it experiences
very low levels of motion. In particular for transcatheter
procedures, the motion of the TEE probe regularly is below the
motion of transcatheter tools previously described. In other words,
the spatial relationship and/or the distance between the
transcatheter tool and the TEE transducer is non-constant and
consequently, when considering 2D image acquisition of a particular
ultrasound plane, the tool tip periodically goes out of an
ultrasound plane currently under observation.
[0008] To make the tool tip appear again in the imaging plane,
readjustment of the imaging plane is required. This in turn
requires a tedious coordination between the interventionist
operating the transcatheter tool and the echographer operating in
particular the ultrasound image acquisition device.
SUMMARY OF THE INVENTION
[0009] It is an object of the invention to allow steering of
two-dimensional ultrasound image acquisition, in particular
steering of an imaging plane of an ultrasound image acquisition
device, so that an object of interest remains visible, in
particular without continuous readjustment of imaging
parameters.
[0010] Accordingly, a method for ultrasound image acquisition, in
particular for tracking an object of interest in ultrasound image
information, a system for ultrasound image acquisition, a
computer-readable medium as well as a program element for
ultrasound image acquisition according to the independent claims
are provided. Preferred embodiments may be taken from the dependent
claims.
[0011] These and other aspects of the present invention will become
apparent from and elucidated with reference to the embodiments
described hereinafter. Exemplary embodiments of the present
invention will be described below with reference to the following
drawings.
[0012] The illustration in the drawings is schematic. In different
drawings, similar or identical elements are provided with similar
or identical reference numerals.
[0013] The figures are not drawn to scale, however may depict
qualitative proportions.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 shows an exemplary embodiment of the relationship
between ultrasound image information and X-ray image information
according to the present invention;
[0015] FIG. 2 shows an exemplary embodiment of a system for
ultrasound image acquisition according to the present invention;
and
[0016] FIG. 3 shows an exemplary embodiment of a method for
ultrasound image acquisition according to the present
invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0017] One aspect of the present invention pertains to steering
and/or aligning an imaging plane of an ultrasound image so that an
object of interest remains visible, i.e. within the imaging plane,
without the requirement of, in particular constant, readjustment of
imaging parameters, in particular ultrasound plane position and
orientation.
[0018] During a certain interventional procedure, both an X-ray
imaging modality e.g. by using a C-arc, as well as an ultrasound
imaging modality like TEE may be employed, with each modality
generating in particular two-dimensional image information.
[0019] Regularly, the ultrasound transducer comprises a transducer
array for obtaining image information of a particular,
two-dimensional ultrasound image plane, which can be adjusted in 3D
by varying the ultrasound emissions of the transducer array.
[0020] One aspect of the present invention is that the orientation
of an ultrasound plane is steered such that the ultrasound plane
comprises the X-ray source. Further, in case the ultrasound imaging
plane also contains the projection of an object of interest, e.g. a
tool tip of a transcatheter tool, on the X-ray detector, said
spatial information is sufficient to establish an ultrasound
imaging plane, in which the tool tip of a transcatheter tool may
move without being able to leave the ultrasound plane. In other
words, in case the ultrasound plane is steered to (always) contain
the X-ray source as well as the projection of the tool tip visible
in the X-ray image information, which projection however is
non-static on the X-ray detector and may thus move, thereby
requiring adjustment of the imaging plane, the tool tip of the
transcatheter tool will remain visible within the ultrasound plane.
Thereby, the ultrasound plane is automatically steered such that
the object of interest lies within the image. No additional use of
three-dimensional images is required, which in this case would only
be used for tracking the tool tip while degrading the frame rate of
the ultrasound image acquisition.
[0021] The steering of the ultrasound plane according to the
present invention allows to present a moving object of interest
inside the ultrasound plane, thereby avoiding a repetitive
appearance and disappearance of the object due to out of plane
movement, either due to active motion of the object of interest or
passive motion e.g. due to the cardiac beats.
[0022] To allow the implementation of the method for ultrasound
image acquisition according to the present invention, it is first
assumed that the ultrasound image information and X-ray image
information are registered. In other words, the spatial
relationship between the ultrasound image information and C-arm
imaging information, in particular comprising further information
such as the relative position of an X-ray source, is known. E.g.,
when considering a two-dimensional X-ray image as well as a
two-dimensional ultrasound image, the angle and position of both
images with respect to each other is assumed to be known in case
said data is registered. Also, a common coordinate system or
reference coordinate system may be established and subsequently
employed, thereby spatially linking the C-arm imaging information
and the ultrasound image information. Further, particular image
information visible in either two-dimensional image is also assumed
to be known. One example of registering ultrasound image
information and X-ray image information is described in
international patent application WO 2011/070477 of the instant
applicant.
[0023] Further, it is assumed that the imaging plane of the
ultrasound image information may be steered electronically, e.g. by
employing a suitable ultrasound transducer array as known in the
art.
[0024] Also, it is assumed that the object of interest can be
tracked, i.e. is visual and detectable within the X-ray image
information. In other words, the X-ray image shall contain a
projection of the object of interest, e.g. the tool tip of the
transcatheter tool.
[0025] Subsequently, the ultrasound plane is steered such that both
the X-ray source as well as the tracked/projected object of
interest in the X-ray image is contained in the ultrasound plane.
In other words, the X-ray source as well as the tracked object of
interest in the X-ray image describe two independent and precisely
defined points of the ultrasound imaging plane. Since the
ultrasound imaging plane also passes through the ultrasound probe
or the ultrasound transducer, which therefore provides a third
defined point, the ultrasound plane is completely and precisely
determined. Since the ultrasound plane is thus readjusted
continuously so that the X-ray source as well as the tracked object
of interest in the X-ray image remains within the ultrasound plane,
also the object of interest itself remains within the ultrasound
imaging plane, since the object of interest naturally is situated
on the line between the X-ray source and the projection of the
object of interest. Indeed, the ultrasound plane is determined by
the object of interest itself as well as the X-ray source, however
with the object of interest being visualized by its projection on
the X-ray detector. Thereby, it is ensured that the object of
interest is also present in the ultrasound imaging plane.
Inaccuracies in the imaging system, e.g. due to X-ray/ultrasound
data registration errors or inaccuracies in the object of interest
localization in the X-ray image, may require to tune the ultrasound
slice thickness accordingly. Regularly, a slice thickness of 1, 2
or 3 mm is employed.
[0026] According to the present invention, a first ultrasound image
plane is thus determinable by employing three points in space, i.e.
the ultrasound transducer tip, the X-ray source as well as the
projection of the object of interest on the X-ray detector. Using
said information, a further, second ultrasound image plane may be
set up, which contains the vector or line between the ultrasound
transducer and the object of interest itself in 3D space within the
reference coordinate system, which position itself is known from
the first ultrasound image information under particular
consideration of the registration between the ultrasound image data
and the X-ray image data. Consequently, a second two-dimensional
ultrasound image may be acquired containing said vector between the
transducer tip and the object of interest, leaving a further degree
of freedom, which can be arbitrarily adjusted. In other words, a
second two-dimensional ultrasound plane may be turned about the
line or vector between the transducer tip and the object of
interest located within patient tissue. Often, such a second
two-dimensional ultrasound plane can be placed orthogonally to the
first ultrasound image plane, thereby acquiring at least some
three-dimensional information, while still only using (two)
two-dimensional images.
[0027] Put another way, assuming that the object of interest is
also tracked in the first ultrasound plane, the second ultrasound
image plane may be placed so that it passes through the object of
interest. This leaves an extra degree of freedom for the
interventionist to choose the orientation of the second ultrasound
image plane freely, while still showing the object of interest. The
tracking in the first ultrasound plane is greatly helped by the
fact that the object of interest position is already known in the
X-ray image and therefore the object of interest is constrained to
lie on the corresponding epipolar line in the ultrasound image.
[0028] Now referring to FIG. 1, an exemplary embodiment of the
relationship between ultrasound image information and X-ray image
information according to the present invention is depicted.
[0029] In FIG. 1, a schematic of an imaging system employing both
X-ray image acquisition as well as ultrasound image acquisition is
depicted. An X-ray source 30 generates X-radiation 31, which is
exemplarily embodied as a cone-beam directed towards an X-ray
detector 32. X-ray detector 32 is exemplarity embodied as a
two-dimensional X-ray detector, comprising a plurality of
individual detector pixel elements arranged in a pixel array, which
however is not depicted in detail in FIG. 1. In the path of
X-radiation 31, an object of interest 36, the tool tip of a
transcatheter tool, is depicted. The object of interest 36
generates a projection 38 on the two-dimensional X-ray detector 32.
Accordingly, a vector or line 48 between the X-ray source 30 and
the projection 38 of the object of interest 36 on X-ray detector 32
is established, on which line 48 also the object of interest 36 is
required to be arranged.
[0030] Further, an ultrasound imaging apparatus embodied
exemplarily as an ultrasound transducer 34 is shown in FIG. 1.
Ultrasound transducer 34 is generating an ultrasound transmission
35, here directed towards the object of interest 36. A first line
or vector 42a from the ultrasound transducer 34 to the X-ray source
30 as well as a second vector or line 42b from the ultrasound
transducer 34 to the projection 38 of the object of interest 36 is
depicted in FIG. 1. The first ultrasound plane 42 is thus
established by the points in space of the ultrasound transducer 34,
the X-ray source 30 and the projection 38 of the object of interest
36. Put another way, the ultrasound plane is established by paths
or vectors 42a,b, and 48.
[0031] Establishing the first ultrasound plane 42 requires a known
spatial relationship between the X-ray image information 40 and the
ultrasound image information 42, which may be performed by a
registration operation of the C-arm acquisition geometry
information and the ultrasound image information for obtaining a
spatial relationship between said two image information. Known
image processing techniques or further means like electromagnetic
tracking unsing EM tracker elements may be employed for said
registering operation. With said first ultrasound plane 42, also a
location in space of the object of interest 36 is known.
Subsequently, for a second ultrasound plane 44, this known location
of the object of interest 36 together with the location of the
ultrasound transducer 34 establishes a line or vector 50 between
the ultrasound transducer 34 and the object of interest 36. The
second ultrasound plane 44 thus comprises always the object of
interest 36 by assuming that said second ultrasound plane 44 always
comprises line 50, thereby allowing a degree of freedom 46, which
can be chosen arbitrarily, e.g. by an operator of the imaging
system 54. In other words, a further ultrasound image plane 44 may
be turned about line 50 between the ultrasound transducer 34 and
the object of interest 36. One preferred alignment of the first
ultrasound plane 42 and the second ultrasound plane 44 is arranging
both planes perpendicular to each another to establish some
three-dimensional reference frame for an interventionist.
[0032] Now referring to FIG. 2, an exemplary embodiment of a system
for ultrasound image acquisition according to the present invention
is depicted.
[0033] An exemplarily application scenario employs a C-arc 33
comprising an X-ray source 30 as well as an X-ray detector 32 with
X-radiation 31 being generated by the X-ray source 30 and being
directed towards the X-ray detector 32. An object to be examined 52
is arranged in the path of X-radiation 31, which is subject to a
transcatheter procedure with an object of interest 36, e.g. a
transcatheter tool being inserted appropriately into object 52. An
ultrasound transducer 34 is arranged in the vicinity of the object
to be examined 52, in particular in the esophagus, embodied as a
TEE ultrasound source. Said particular embodiment however is not
depicted in FIG. 2, which is rather referring to a general
ultrasound transducer 34.
[0034] A first ultrasound plane 42 is established by the X-ray
source 30, the projection 38 of the object of interest 36 and the
ultrasound transducer 34 in three-dimensional space.
[0035] Imaging system 54 comprises a processing element 56 with
control elements 58, exemplarily embodied as keyboard and manual
input devices, as well as a display unit 60 for displaying at least
some image information of the X-ray image information and the first
and second ultrasound image information. The operator of the
imaging system 54 may provide a suitable image information on
display 60a to the interventionist operating to assist in the
procedure. By determining the three-dimensional position in space
of the object of interest 36, a line 50 between the transducer 34
and the object of interest 36 may be established, allowing a second
ultrasound plane 44, not depicted in FIG. 2 to be established,
which may be turned about line 50 at the discretion of one of the
operator and the interventionist.
[0036] Now referring to FIG. 3, an exemplary embodiment of a method
for ultrasound image acquisition according to the present invention
is depicted.
[0037] FIG. 3 describes a method 10 for ultrasound image
acquisition, in particular for tracking an object of interest in
ultrasound image information comprising receiving 12 X-ray image
information and ultrasound image information, detecting 14 an
object of interest in the X-ray image information and steering 16
two-dimensional ultrasound image acquisition such that the object
of interest is within the first ultrasound image plane. A
registering procedure 18 aids in obtaining a spatial relation
between the X-ray image information and the ultrasound image
information. The determined first ultrasound image plane may be
visualized 20. A second ultrasound image information corresponding
to a second ultrasound image plane may be obtainable 22, which may
also be visualized separately or conjointly with at least one of
the first ultrasound image plane and the X-ray image information.
An operator may adjust 24 the thickness of at least one of the
first ultrasound image plane and the second ultrasound image plane
to aid in having the object of interest within at least one of the
respective image planes.
LIST OF REFERENCE SIGNS
[0038] 10 method for ultrasound image acquisition [0039] 12
receiving X-ray image information and ultrasound image information
[0040] 14 detecting an object of interest in the X-ray image
information [0041] 16 steering two-dimensional ultrasound image
acquisition [0042] 18 registering X-ray image information and
ultrasound image information [0043] 20 visualizing [0044] 22
obtaining second ultrasound image information [0045] 24 adjusting
slice thickness of ultrasound image plane [0046] 30 X-ray source
[0047] 31 X-radiation [0048] 32 X-ray detector [0049] 33 C-arc
[0050] 34 ultrasound transducer [0051] 35 ultrasound transmission
[0052] 36 object of interest [0053] 38 projection [0054] 40 X-ray
image information [0055] 42 first ultrasound image plane [0056] 44
second ultrasound image plane [0057] 46 degree of freedom [0058] 48
line X-ray source projection object of interest [0059] 50 line
ultrasound transducer object of interest [0060] 52 object to be
examined [0061] 54 imaging system [0062] 56 processing element
[0063] 58 control element [0064] 60 display unit
* * * * *