U.S. patent application number 15/950542 was filed with the patent office on 2018-08-16 for method and apparatus for analyzing elastography of tissue using ultrasound waves.
This patent application is currently assigned to Samsung Electronics Co., Ltd.. The applicant listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to Ki-wan CHOI, Hyoung-ki LEE, Ji-young PARK, Jong-hwa WON.
Application Number | 20180228471 15/950542 |
Document ID | / |
Family ID | 50066704 |
Filed Date | 2018-08-16 |
United States Patent
Application |
20180228471 |
Kind Code |
A1 |
PARK; Ji-young ; et
al. |
August 16, 2018 |
METHOD AND APPARATUS FOR ANALYZING ELASTOGRAPHY OF TISSUE USING
ULTRASOUND WAVES
Abstract
A method and apparatus for analyzing elastography of tissue
using ultrasound waves, wherein elastography information of tissue
in a region of interest (ROI) is analyzed by irradiating ultrasound
waves for diagnosis towards the ROI to which a shear wave is
induced from an ultrasound probe, receiving echo ultrasound waves,
and acquiring three-dimensional (3D) ultrasound images with respect
to the ROI.
Inventors: |
PARK; Ji-young; (Yongin-si,
KR) ; CHOI; Ki-wan; (Anyang-si, KR) ; LEE;
Hyoung-ki; (Seongnam-si, KR) ; WON; Jong-hwa;
(Seoul, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Suwon-si |
|
KR |
|
|
Assignee: |
Samsung Electronics Co.,
Ltd.
Suwon-si
KR
|
Family ID: |
50066704 |
Appl. No.: |
15/950542 |
Filed: |
April 11, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13919303 |
Jun 17, 2013 |
9968333 |
|
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15950542 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 8/469 20130101;
A61B 8/085 20130101; A61B 8/483 20130101; A61B 8/485 20130101 |
International
Class: |
A61B 8/08 20060101
A61B008/08; A61B 8/00 20060101 A61B008/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 8, 2012 |
KR |
10-2012-0086937 |
Claims
1. A method comprising: inducing a shear wave in a tissue in a
human body by Acoustic Radiation Force Impulse (ARFI) using an
ultrasound probe having a two-dimensional (2D) transducer array;
irradiating ultrasound waves in the tissue using the ultrasound
probe; acquiring three-dimensional (3D) ultrasound data using echo
ultrasound waves of the irradiated ultrasound waves and a 3D plane
scan method in which a 3D volume of the tissue is scanned by the 2D
transducer array; calculating displacement components of the
induced shear wave in the tissue based on the acquired 3D
ultrasound data; calculating a speed of the induced shear wave
using the calculated displacement components; calculating a shear
modulus of the tissue using the calculated speed of the induced
shear wave; and displaying at least one 3D image using the
calculated speed of the induced shear wave.
2. The method of claim 1, wherein the calculating the displacement
components of the induced shear wave in the tissue comprises using
a wave equation with respect to the induced shear wave.
3. The method of claim 1, wherein the irradiating with the
ultrasound waves is performed for diagnosis of the tissue and
comprises beamforming the ultrasound waves in a defocusing
method.
4. The method of claim 1, wherein the acquiring of the 3D
ultrasound data comprises beamforming the echo ultrasound
waves.
5. The method of claim 1, further comprising displaying at least
one image representing the calculated displacement components of
the induced shear wave.
6. The method of claim 1, further comprising displaying a modulus
of elasticity based on the calculated speed of the induced shear
wave.
7. The method of claim 1, wherein the speed of the shear wave is
calculated using the following equation: .differential. 2 u
.differential. t 2 = C s 2 ( .differential. 2 u .differential. x 2
+ .differential. 2 u .differential. y 2 + .differential. 2 u
.differential. z 2 ) ##EQU00003## where u denotes a displacement of
the shear wave, t denotes time, and x, y, and z denote the
respective calculated displacement components.
8. The method of claim 7, wherein the shear modulus of the tissue
is calculated using the following equation: G=p.times.C.sub.S.sup.2
where G denotes the shear modulus of the tissue, and p denotes a
density of the tissue.
9. A non-transitory computer-readable recording medium storing a
computer-readable program for executing a method comprising:
inducing a shear wave in a tissue in a human body by Acoustic
Radiation Force Impulse (ARFI) using an ultrasound probe having a
two-dimensional (2D) transducer array; irradiating ultrasound waves
in the tissue using the ultrasound probe; acquiring
three-dimensional (3D) ultrasound data using echo ultrasound waves
of the irradiated ultrasound waves and a 3D plane scan method in
which a 3D volume of the tissue is scanned by the 2D transducer
array; calculating displacement components of the induced shear
wave in the tissue based on the acquired 3D ultrasound data;
calculating a speed of the induced shear wave using the calculated
displacement components; calculating a shear modulus of the tissue
using the calculated speed of the induced shear wave; and
displaying at least one 3D image using the calculated speed of the
induced shear wave.
10. An apparatus comprising: an ultrasound probe having a
two-dimensional (2D) transducer array; a display; at least one
hardware processor; computer readable memory comprising
instructions that, when executed by the at least one hardware
processor, perform operations comprising: controlling the
ultrasound probe to induce a shear wave in a tissue in a human body
by Acoustic Radiation Force Impulse (ARFI); controlling the
ultrasound probe to irradiate ultrasound waves in the tissue;
acquiring three-dimensional (3D) ultrasound data using echo
ultrasound waves of the irradiated ultrasound waves and a 3D plane
scan method in which a 3D volume of the tissue is scanned by the 2D
transducer array; calculating displacement components of the
induced shear wave in the tissue based on the acquired 3D
ultrasound data; calculating a speed of the induced shear wave
using the calculated displacement components; calculating a shear
modulus of the tissue using the calculated speed of the induced
shear wave; and displaying at least one 3D image using the
calculated speed of the induced shear wave on the display.
11. The apparatus of claim 10, wherein the controlling the
ultrasound probe to irradiate the ultrasound waves comprises
irradiating plane waves by beamforming the ultrasound waves in a
defocusing method and wherein the irradiating of the ultrasound
waves is performed for diagnosis of the tissue.
12. The apparatus of claim 10, wherein the acquiring of the 3D
ultrasound data comprises beamforming the echo ultrasound
waves.
13. The apparatus of claim 10, wherein the operations further
comprise: acquiring elastography information of the tissue by
calculating an average value of the calculated shear modulus in at
least two image frames; and displaying, on the display, at least
one image using the acquired elastography information.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/919,303, filed on Jun. 17, 2013, which
claims the benefit of Korean Patent Application No.
10-2012-0086937, filed on Aug. 8, 2012, in the Korean Intellectual
Property Office, the disclosures of which are incorporated herein
in their entirety by reference.
BACKGROUND
1. Field
[0002] One or more embodiments of the present disclosure relate to
methods and apparatuses for analyzing elastography of tissue of a
human or animal subject using ultrasound waves.
2. Description of the Related Art
[0003] To diagnose a disease, establish a treatment plan, or
evaluate a treatment progress using ultrasound images in medical
institutions, a medical practitioner reads ultrasound images of a
patient, which are displayed on a monitor, to observe states or
sequential histological changes of tumorous or cancerous tissue.
However, since ultrasound images are read by a medical practitioner
with the naked eye, the same ultrasound image may be analyzed
differently depending on the angle of view of the medical
practitioner, thereby making the potential for a measurement error
large. In addition, occasionally, a medical practitioner
incorrectly recognizes abnormal tissue, such as tumorous or
cancerous tissue in ultrasound images as normal tissue, that is
tissue without tumors or cancer.
[0004] However, recently, Computer-Aided Diagnosis (CAD) systems
primarily discerning medical images, such as ultrasound images,
Magnetic Resonance Imaging (MRI) images, and Computed Tomography
(CT) images, and indicating the presence or absence of abnormal
tissue, a location of the abnormal tissue, and the like to a
medical practitioner have been developed. The CAD systems, which
detect abnormal tissue by processing the presence or absence of
abnormal tissue in a medical image, a size of the abnormal tissue,
a location of the abnormal tissue, and the like using a computer
system and provide a detection result to a medical practitioner to
aid image diagnosis by the medical practitioner, may be used in
combination with medical devices, such as an ultrasound device, an
MRI device, and a CT device.
SUMMARY
[0005] Provided are methods and apparatuses for analyzing
elastography of tissue in a subject using ultrasound waves.
[0006] Provided are computer-readable recording media storing a
computer-readable program for executing the methods.
[0007] Additional aspects will be set forth in part in the
description which follows and, in part, will be apparent from the
description, or may be learned by practice of the presented
embodiments.
[0008] According to an aspect of the present disclosure, a method
of analyzing elastography of tissue using ultrasound waves
includes: irradiating ultrasound waves for diagnosis towards a
region of interest (ROI) in a subject, to which a shear wave is
induced, from an ultrasound probe having a two-dimensional (2D)
transducer array; acquiring three-dimensional (3D) ultrasound
images with respect to the ROI using echo ultrasound waves of the
ultrasound waves for diagnosis, which have been received by the
ultrasound probe; measuring a displacement of the shear wave in the
ROI from the acquired 3D ultrasound images; and analyzing
information about elastography of tissue in the ROI using the
measured displacement of the shear wave.
[0009] According to another aspect of the present disclosure, a
computer-readable recording medium storing a computer-readable
program for executing the method of analyzing elastography of
tissue using ultrasound waves in a computer system is provided.
[0010] According to another aspect of the present disclosure, an
apparatus for analyzing elastography of tissue using ultrasound
waves includes: an ultrasound probe for irradiating ultrasound
waves for diagnosis towards a region of interest (ROI) in a
subject, to which a shear wave is induced, using a two-dimensional
(2D) transducer array; an ultrasound image processor for acquiring
three-dimensional (3D) ultrasound images with respect to the ROI
using echo ultrasound waves of the ultrasound waves for diagnosis,
which have been received by the ultrasound probe; a displacement
measuring unit for measuring a displacement of the shear wave in
the ROI from the acquired 3D ultrasound images; and an elastography
analyzing unit for analyzing information about elastography of
tissue in the ROI using the measured displacement of the shear
wave.
[0011] According to another aspect of the present disclosure, a
system to analyze elastography of tissue using ultrasound waves is
provided. The system includes an ultrasound probe to irradiate a
region of interest (ROI) in a subject with ultrasound waves thereby
inducing a shear wave in the ROI and a processor. The processor
includes an ultrasound image processor to acquire three-dimensional
(3D) ultrasound images of the ROI using echo ultrasound waves
provided by the ultrasound probe, wherein the echo ultrasound waves
are obtained from the ultrasound waves after the ultrasound waves
are reflected from the ROI or regions around the ROI, a
displacement measuring unit to measure a displacement of the shear
wave in the ROI based on the acquired 3D ultrasound images, and an
elastography analyzing unit to analyze information about
elastography of tissue in the ROI using the measured displacement
of the shear wave.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The patent or application file contains at least one drawing
executed in color. Copies of this patent or patent application
publication with color drawing(s) will be provided by the Office
upon request and payment of the necessary fee. These and/or other
aspects will become apparent and more readily appreciated from the
following description of the embodiments, taken in conjunction with
the accompanying drawings in which:
[0013] FIG. 1 is a block diagram of an apparatus for analyzing
elastography of tissue using ultrasound waves, according to an
embodiment of the present disclosure;
[0014] FIG. 2A is a diagram for describing a shear wave according
to an embodiment of the present disclosure;
[0015] FIG. 2B is an image showing that a shear wave is induced to
a region of interest (ROI) according to an embodiment of the
present disclosure;
[0016] FIG. 3A is a perspective view showing a case where
ultrasound waves for diagnosis are irradiated by a 3D volume
acquisition method according to an embodiment of the present
disclosure;
[0017] FIG. 3B is a perspective view showing a case where
ultrasound waves for diagnosis are irradiated by a 3D plane scan
method according to an embodiment of the present disclosure;
[0018] FIG. 4A is an image showing a simulation result of a case
where a shear modulus is analyzed from 2D ultrasound images
acquired using an existing ultrasound probe having a 1D transducer
array;
[0019] FIG. 4B is an image showing a simulation result of a case
where a shear modulus is analyzed from 3D ultrasound images
acquired using an ultrasound probe having a 2D transducer array
according to an embodiment of the present disclosure; and
[0020] FIG. 5 is a flowchart illustrating a method of analyzing
elastography of tissue using ultrasound waves, according to an
embodiment of the present disclosure.
DETAILED DESCRIPTION
[0021] Reference will now be made in detail to embodiments,
examples of which are illustrated in the accompanying drawings,
wherein like reference numerals refer to like elements throughout.
In this regard, the present embodiments may have different forms
and should not be construed as being limited to the descriptions
set forth herein. Accordingly, the embodiments are merely described
below, by referring to the figures, to explain aspects of the
present description.
[0022] FIG. 1 is a block diagram of an apparatus 1 for analyzing
elastography of tissue using ultrasound waves, according to an
embodiment of the present disclosure. Referring to FIG. 1, the
apparatus 1 may include, for example, a processor 10 and an
ultrasound probe 20. The processor 10 may include, for example, an
ultrasound image processor 110, a displacement measuring unit 120,
and an elastography analyzing unit 130.
[0023] Only hardware components associated with the current
embodiment are described in FIG. 1 to prevent features of the
current embodiment from being obscured. However, it will be
understood by one of ordinary skill in the art that the apparatus 1
may further include other general-use hardware components.
[0024] Recently, systems, such as Computer-Aided Diagnosis (CAD)
systems, primarily discerning medical images, such as ultrasound
images, Magnetic Resonance Imaging (MRI) images, and Computed
Tomography (CT) images, and providing the presence or absence of
abnormal tissue, a location of the abnormal tissue, and the like to
a medical practitioner have been used. The systems may detect
abnormal tissue by processing the presence or absence of abnormal
tissue in a medical image, a size of the abnormal tissue, a
location of the abnormal tissue, and the like using a computer
system and provide a detection result to a medical practitioner to
aid image diagnosis by the medical practitioner.
[0025] The apparatus 1 may be used in systems such as the CAD
systems described above. Ultrasound elastography technology may be
used to diagnose tissue by analyzing elastography of the tissue and
discerning a stiffness difference between normal tissue and
abnormal tissue. In particular, the apparatus 1 may be used to
discern a state of tissue in the human body, or in animal tissue,
such as whether abnormal tissue, such as cancer, exists or whether
tissue has been completely treated when the tissue is treated using
High Intensity Focused Ultrasound (HIFU) or the like, by analyzing
elastography of the tissue using ultrasound waves.
[0026] In general, it is known that abnormal tissue has a
difference in stiffness compared with normal tissue, and the
abnormal tissue may be discerned by analyzing this difference.
Thus, abnormal tissue, such as cancerous tissue or tissue having a
tumor, may have a higher elastography score than surrounding normal
tissue. Thus, a shear modulus of the abnormal tissue is higher than
that of the surrounding normal tissue. In addition, when tissue is
treated by necrosing it using ultrasound waves for treatment, such
as in HIFU, an elastography score of the tissue increases as
necrosis of the tissue progresses. That is, a state change of
tissue may be determined or monitored by an elastography of the
tissue. Thus, if elastography of the tissue is perceived using
ultrasound waves, a medical practitioner may non-invasively monitor
a state of the tissue without having to view the tissue in the
human body with the naked eye.
[0027] The apparatus 1 may be configured as a system capable of
aiding image diagnosis by a medical practitioner in a medical
institution and may be used to diagnose a disease, establish a
treatment plan, and evaluate a treatment progress by providing a
result of analyzing elastography of tissue using ultrasound waves.
Alternatively, the apparatus 1 may be used to detect diseased
tissue in a living animal or may be used to inspect animal tissue
of a living or dead animal, such as to determine the quality of
animal meat for human consumption. A configuration and operation of
the apparatus 1 will now be described in more detail.
[0028] The ultrasound probe 20 induces a shear wave by radiating
ultrasound waves upon a region of interest (ROI) 30 in the human
body before elastography is analyzed. To quantitatively analyze the
elastography using the ultrasound waves for diagnosis, Acoustic
Radiation Force Impulses (AFRIs) equivalent to the ultrasound waves
for diagnosis need to be applied to the human or animal body in
advance to cause a displacement of tissue. That is, the AFRIs
induce a shear wave to the tissue to cause the displacement of the
tissue.
[0029] FIG. 2A is a diagram for describing a shear wave according
to an embodiment of the present disclosure. Referring to FIG. 2A,
when a force of a point impulse is applied along a z-axis
direction, a P wave that is a longitudinal wave, an S wave that is
a transverse wave, and a PS wave that is a coupling wave of the P
wave and the S wave are generated. The shear wave is a wave
vibrating along a wave traveling direction and traveling along a
y-axis direction from a vibration source to which the force is
applied, i.e., the S wave.
[0030] It is described in the current embodiment for convenience of
description that the ultrasound waves for diagnosis from the
ultrasound probe 20 are used for the force of the point impulse for
inducing the shear wave. However, the current embodiment is not
limited thereto, and a treatment ultrasound device, such as an HIFU
device, or an oscillator located outside the apparatus 1 may also
be used to induce the shear wave. That is, it will be understood by
one of ordinary skill in the art that a device for inducing the
shear wave to the ROI 30 is not limited to any one device and may
include a variety of different devices.
[0031] FIG. 2B is an image showing a shear wave being induced in
the ROI 30 according to an embodiment of the present disclosure.
Referring to FIG. 2B, the ultrasound probe 20 induces the shear
wave in the ROI 30 by radiating the ultrasound waves for diagnosis
along a depth-axis direction to form a focal point on the ROI 30
under the skin of the human body, thereby irradiating the ROI.
[0032] Referring back to FIG. 1, the ultrasound probe 20 radiate
the ultrasound waves towards the ROI 30 thereby irradiating the ROI
30 to obtain ultrasound images of the ROI 30 and regions around the
ROI 30 after the shear wave is induced in the ROI 30.
[0033] The ultrasound probe 20 may radiate plane waves by
beamforming the ultrasound waves in a defocusing method. The plane
waves are used in the defocusing method is to allow the shear wave
to be observed in a wider range.
[0034] In more detail, the ultrasound probe 20 may use the
defocusing method so that a displacement of the shear wave is
observed in a wider range than would be observed if a focusing
method were used. In addition, by using plane waves having a
strength that is maintained relatively constant even when the plane
waves reach a location deep in the human body, a displacement of
the shear wave may be more correctly observed than spherical waves
having a strength that weakens as they reach a deep location.
[0035] The ultrasound probe 20 may include a 2D transducer array to
acquire 3D ultrasound images at high speed, as described with
reference to FIGS. 3A and 3B.
[0036] FIG. 3A is a perspective view showing ultrasound waves being
radiated using a 3D volume acquisition method according to an
embodiment of the present disclosure. Referring to FIG. 3A, the
ultrasound probe 20 may irradiate the ROI 30 with the ultrasound
waves using the 2D transducer array to scan a 3D volume of the ROI
30 and regions around the ROI 30 at once, that is, to scan the 3D
volume simultaneously or within a very short period of time.
[0037] FIG. 3B is a perspective view showing a case where the
ultrasound waves are radiated using a 3D plane scan method
according to an embodiment of the present disclosure. Referring to
FIG. 3B, the ultrasound probe 20 may irradiate the ROI 30 with the
ultrasound waves using the 2D transducer array to scan the ROI 30
and regions around the ROI 30 on a plane basis and generate 3D
volume data with respect to the ROI 30.
[0038] Referring back to FIG. 1, the ultrasound probe 20 receives
echo ultrasound waves. The echo ultrasound waves are the original
ultrasound waves after being reflected from the ROI 30 and the
regions around the ROI 30. As described above, since the ultrasound
probe 20 radiates the ultrasound waves using either of the 2D
transducer array in the 3D volume acquisition method or the 3D
plane scan method, the ultrasound probe 20 may receive echo
ultrasound waves including 3D information about the ROI 30 and the
regions around the ROI 30.
[0039] In general, it is known that a wave speed of the shear wave
is about 1 m/s to about 10 m/s. Thus, to observe the shear wave
with a resolution of several mm, ultrasound images may need to be
acquired in units of thousands of frames per second. To acquire
ultrasound images of thousands of frames per second, the ultrasound
waves for diagnosis need to be irradiated and received at a speed
faster than the wave speed of the shear wave. In this case, since
an existing 3D line scan method can scan only a single scan line at
a time, ultrasound images of thousands of frames per second cannot
be acquired and it may be difficult to correctly measure the
movement of the shear wave using the 3D line scan method. Thus, by
instead using the methods shown in FIG. 3A or 3B, 3D, ultrasound
images of thousands of frames per second may be acquired using the
2D transducer array, thereby correctly measuring the movement of
the shear wave.
[0040] The ultrasound image processor 110 may acquire 3D ultrasound
images of thousands of frames per second by processing the echo
ultrasound waves received by the ultrasound probe 20. In other
words, the ultrasound image processor 110 may acquire 3D ultrasound
images of thousands of frames per second by beamforming the echo
ultrasound waves received by the ultrasound probe 20. Since a
typical process of processing ultrasound images by using echo
ultrasound waves would be apparent to one of ordinary skill in the
art, a detailed description thereof is omitted.
[0041] The displacement measuring unit 120 measures a displacement
of the shear wave in the ROI 30 from the acquired 3D ultrasound
images. Since the 3D ultrasound images are acquired by the
ultrasound image processor 110 as described above, the displacement
of the shear wave that is measured by the displacement measuring
unit 120 corresponds to measured 3D movement of the shear wave.
That is, the measured displacement of the shear wave has
displacement components corresponding to the x-, y-, and z-axes in
an arbitrary 3D coordinate space.
[0042] Since a typical process of measuring a displacement of a
shear wave by analyzing movement of the shear wave, which is shown
in ultrasound images of thousands of frames per second, would be
apparent to one of ordinary skill in the art, a detailed
description thereof has been omitted.
[0043] The elastography analyzing unit 130 analyzes elastography
information of tissue in the ROI 30 using the measured displacement
of the shear wave. The elastography information analyzed in the
current embodiment may include a shear modulus.
[0044] The elastography analyzing unit 130 may calculate a shear
modulus of the tissue in the ROI 30 using the displacement
components corresponding to 3D coordinate axes (x-, y-, and z-axes)
that are included in the measured displacement of the shear wave.
In this case, the elastography analyzing unit 130 may calculate the
shear modulus using a wave equation with respect to the shear
wave.
[0045] In more detail, the elastography analyzing unit 130 may
calculate a moving speed of the shear wave using the displacement
components corresponding to the 3D coordinate axes that are
included in the measured displacement of the shear wave.
.differential. 2 u .differential. t 2 = C S 2 ( .differential. 2 u
.differential. x 2 + .differential. 2 u .differential. y 2 +
.differential. 2 u .differential. z 2 ) ( 1 ) ##EQU00001##
[0046] In Equation 1, u denotes a displacement of a shear wave and
C.sub.S denotes a moving speed of the shear wave. Although the
elastography analyzing unit 130 may calculate the moving speed
C.sub.S of the shear wave using Equation 1 in the current
embodiment, the current embodiment is not limited thereto.
[0047] The elastography analyzing unit 130 may calculate a shear
modulus of the tissue in the ROI 30 using the calculated moving
speed C.sub.S of the shear wave.
G=.rho..times.C.sub.S.sup.2 (2)
[0048] In Equation 2, G denotes a shear modulus, and p denotes
density of a medium. Since the elastography analyzing unit 130 may
calculate the moving speed C.sub.S of the shear wave using Equation
1 as described above and p is an already known value, the
elastography analyzing unit 130 may calculate the shear modulus G
using Equation 2. Although the elastography analyzing unit 130
calculates the shear modulus G using Equation 2 in the current
embodiment, the current embodiment is not limited thereto.
[0049] If the elastography analyzing unit 130 analyzes the shear
modulus G in units of at least two frames in the 3D ultrasound
images, the elastography analyzing unit 130 may calculate a final
shear modulus G by calculating a mean value of the calculated shear
moduli G.
[0050] Alternatively, the elastography analyzing unit 130 may
calculate the shear modulus G using Equation 3 below.
.rho. .differential. 2 u z .differential. t 2 = G ( x , y , z ) (
.differential. 2 u z .differential. x 2 + .differential. 2 u z
.differential. y 2 + .differential. 2 u z .differential. z 2 )
.revreaction. G ( x , y , z ) = .rho. .differential. 2 u z
.differential. t 2 .differential. 2 u z .differential. x 2 +
.differential. 2 u z .differential. y 2 + .differential. 2 u z
.differential. z 2 ( 3 ) ##EQU00002##
[0051] That is, the elastography analyzing unit 130 may calculate
the shear modulus G using Equation 3 in which Equations 1 and 2
have been combined.
[0052] As described above, since the ultrasound image processor 110
acquires the 3D ultrasound images at thousands of frames per
second, and the displacement measuring unit 120 measures the
displacement of the shear wave having the 3D displacement
components, the elastography analyzing unit 130 may calculate the
shear modulus G by considering all of the 3D displacement
components. That is, the shear modulus G calculated by the
elastography analyzing unit 130 has a more accurate value than when
it is calculated by two-dimensionally measuring the
displacement.
[0053] Thus, a shear modulus may be more correctly analyzed when
the shear modulus is analyzed based on 3D ultrasound images
acquired by the ultrasound probe 20 having a 2D transducer array
according to the current embodiment than when the shear modulus is
analyzed based on 2D ultrasound images acquired by an ultrasound
probe having a 1D transducer array.
[0054] FIG. 4A is an image showing a simulation result of a case
where a shear modulus is analyzed from 2D ultrasound images
acquired using an existing ultrasound probe having a 1D transducer
array. Referring to FIG. 4A, a displacement map showing a 2D
displacement of a shear wave and a corresponding shear modulus map
are shown.
[0055] FIG. 4B is an image showing a simulation result of a case
where a shear modulus is analyzed from 3D ultrasound images
acquired using an ultrasound probe having a 2D transducer array
according to an embodiment of the present disclosure. Referring to
FIG. 4B, a displacement map showing a 3D displacement of a shear
wave and a corresponding shear modulus map are shown.
[0056] Comparing them with each other, when 2D ultrasound images
are acquired using the ultrasound probe having a 1D transducer
array according to FIG. 4A, since a displacement of the shear wave
may not be considered along all directions in a 3D space, the shear
modulus may not be correctly analyzed.
[0057] However, when 3D ultrasound images are acquired using the
ultrasound probe having a 2D transducer array according to the
current embodiment, since a displacement of the shear wave may be
considered along all directions (x-, y-, and z-axes) in a 3D space,
the shear modulus may be more correctly analyzed than in the case
of FIG. 4A.
[0058] Referring back to FIG. 1, the elastography analyzing unit
130 provides elastography information based on the calculated shear
modulus. Although not shown in FIG. 1, the elastography
information, such as the shear modulus analyzed by the elastography
analyzing unit 130, may be provided to a user, such as a medical
practitioner, through a display device (not shown) and may be used
to perceive a state or a characteristic change in tissue.
[0059] FIG. 5 is a flowchart illustrating a method of analyzing
elastography of tissue using ultrasound waves, according to an
embodiment of the present disclosure. Referring to FIG. 5, the
method includes operations sequentially processed by the apparatus
1 shown in FIG. 1, although the operations may alternatively be
performed by apparatuses or systems other than apparatus 1. Thus,
although omitted below, the descriptions of the apparatus 1 above
also apply to the method according to the current embodiment.
[0060] In operation 501, the ultrasound probe 20 may irradiate ROI
30 with ultrasound waves using a 2D transducer array, thereby
inducing a shear wave in ROI 30.
[0061] In operation 502, the ultrasound image processor 110 may
acquire 3D ultrasound images with respect to the ROI 30 using echo
ultrasound waves, which are echos of the ultrasound waves that are
received by the ultrasound probe 20.
[0062] In operation 503, the displacement measuring unit 120 may
measure a displacement of the shear wave in the ROI 30 from the
acquired ultrasound images.
[0063] In operation 504, the elastography analyzing unit 130 may
analyze elastography information of tissue in the ROI 30 using the
measured displacement of the shear wave.
[0064] As described above, according to the one or more of the
above embodiments of the present disclosure, since
three-dimensional ultrasound images with respect to an ROI are
obtained at a relatively high speed, a displacement of a shear wave
induced in tissue in the human body may be correctly measured. In
addition, since the displacement of the shear wave is
three-dimensionally measured using the three-dimensional ultrasound
images, a shear modulus of the tissue in the human body may be
accurately calculated and provided. Further, decision-making by a
medical practitioner in diagnosis or treatment of a disease of a
patient may be aided using analyzed information about
elastography.
[0065] The embodiments of the present disclosure can be written as
computer programs and can be implemented in general-use digital
computers that execute the programs using a computer-readable
recording medium. In addition, a structure of data used in the
embodiments of the present disclosure may be recorded on a
computer-readable recording medium using various means. Examples of
the computer-readable recording medium include storage media, such
as magnetic storage media (e.g., ROM, floppy disks, hard disks,
etc.) and optical recording media (e.g., CD-ROMs, or DVDs).
[0066] In addition, other embodiments of the present disclosure can
also be implemented through computer-readable code/instructions
in/on a medium, e.g., a computer-readable recording medium, to
control at least one processing element to implement any above
described embodiment. The computer-readable recording medium can
correspond to any medium/media permitting the storage and/or
transmission of the computer-readable code.
[0067] The computer-readable code can be recorded/transferred on a
medium in a variety of ways, with examples of the computer-readable
recording medium including recording media, such as magnetic
storage media (e.g., ROM, floppy disks, hard disks, etc.) and
optical recording media (e.g., CD-ROMs, or DVDs), and transmission
media such as Internet transmission media. Thus, the medium may be
such a defined and measurable structure including or carrying a
signal or information, such as a device carrying a bitstream
according to one or more embodiments of the present disclosure. The
media may also be a distributed network, so that the
computer-readable code is stored/transferred and executed in a
distributed fashion. Furthermore, the processing element could
include a processor or a computer processor, and processing
elements may be distributed and/or included in a single device.
[0068] The described hardware devices may be configured to act as
one or more software modules in order to perform the operations of
the above-described embodiments, or vice versa. Any one or more of
the software modules described herein may be executed by a
controller such as a dedicated processor unique to that unit or by
a processor common to one or more of the modules. The described
methods may be executed on a general purpose computer or processor
or may be executed on a particular machine such as the various
systems and apparatusses described herein.
[0069] It should be understood that the exemplary embodiments
described therein should be considered in a descriptive sense only
and not for purposes of limitation. Descriptions of features or
aspects within each embodiment should typically be considered as
available for other similar features or aspects in other
embodiments.
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