U.S. patent application number 12/871328 was filed with the patent office on 2010-12-23 for ultrasonic imaging apparatus.
Invention is credited to Mitsuaki ITO, Takashi KASHIWAGI, Takeshi MATSUMURA, Naoyuki MURAYAMA, Takashi OSAKA, Kouji WAKI.
Application Number | 20100324421 12/871328 |
Document ID | / |
Family ID | 34622198 |
Filed Date | 2010-12-23 |
United States Patent
Application |
20100324421 |
Kind Code |
A1 |
WAKI; Kouji ; et
al. |
December 23, 2010 |
ULTRASONIC IMAGING APPARATUS
Abstract
An ultrasonic imaging apparatus according to the present
invention includes an ultrasonic probe (2) for receiving and
transmitting ultrasonic waves from/to an object (1), ultrasound
image structuring means (6) for generating an ultrasound image from
a reflected echo signal received by the ultrasonic probe, elastic
image structuring means (7) for obtaining a physical quantity of
the elasticity of a region of the object corresponding to the
ultrasound image from the reflected echo signal and generating a
color elastic image, display means (9) for overlaying the
ultrasound image to the color elastic image, or arranging the
ultrasound image and the color elastic image and displaying the
resultant image on a screen, and input means (17) for variably
setting a corresponding relationship between a hue of the color
elastic image and the level of the physical quantity displayed on
the screen. The level of the elasticity, such as the strain of each
region in the tissue or an elastic modulus, is displayed with
colors in accordance with the interest of the examiner, thus
improving the convenience of use.
Inventors: |
WAKI; Kouji; (Chiba, JP)
; OSAKA; Takashi; (Chiba, JP) ; ITO; Mitsuaki;
(Chiba, JP) ; MATSUMURA; Takeshi; (Chiba, JP)
; MURAYAMA; Naoyuki; (Chiba, JP) ; KASHIWAGI;
Takashi; (Chiba, JP) |
Correspondence
Address: |
ANTONELLI, TERRY, STOUT & KRAUS, LLP
1300 NORTH SEVENTEENTH STREET, SUITE 1800
ARLINGTON
VA
22209-3873
US
|
Family ID: |
34622198 |
Appl. No.: |
12/871328 |
Filed: |
August 30, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10580100 |
May 19, 2006 |
|
|
|
12871328 |
|
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Current U.S.
Class: |
600/443 |
Current CPC
Class: |
A61B 8/14 20130101; A61B
8/08 20130101; A61B 8/485 20130101 |
Class at
Publication: |
600/443 |
International
Class: |
A61B 8/14 20060101
A61B008/14 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 21, 2003 |
JP |
2003-391997 |
Nov 25, 2003 |
JP |
2003-393305 |
Claims
1. An ultrasonic imaging apparatus comprising: an ultrasonic probe
that receives and sends ultrasonic waves from/to an object;
ultrasound image structuring means that generates an ultrasound
image on the basis of a reflected echo signal received by the
ultrasonic probe; elastic image structuring means that obtains a
strain or an elastic modulus of the object of a region
corresponding to the ultrasound image on the basis of the reflected
echo signal and generates a color elastic image; display means that
overlays the ultrasound image to the color elastic image, or
arranges the ultrasound image and the color elastic image and
displays the resultant image on a screen; and setting means that
assigns colors from a maximum value of the strain or the elastic
modulus on the basis of an average of the strain or the elastic
modulus.
2. An ultrasonic imaging apparatus according to claim 1, wherein
the average of the strain or the elastic modulus is calculated by
calculation of (a total amount of strain or elastic modulus)/(a
number of pixels).
3. An ultrasonic imaging apparatus according to claim 2, wherein,
the total amount of strain or the elastic modulus is calculated by
distributing the strain or the elastic modulus and adding the
distributed strain or the elastic modulus.
4. An ultrasonic imaging apparatus comprising: an ultrasonic probe
that receives and sends ultrasonic waves from/to an object;
ultrasound image structuring means that generates an ultrasound
image on the basis of a reflected echo signal received by the
ultrasonic probe; elastic image structuring means that obtains a
strain or an elastic modulus of the object of a region
corresponding to the ultrasound image on the basis of the reflected
echo signal and generates a color elastic image; display means that
overlays the ultrasound image to the color elastic image, or
arranges the ultrasound image and the color elastic image and
displays the resultant image on a screen; and setting means that
assigns hue information so as to display a hard part of the region
with a color and a soft part of the region with another color on
the basis of an average of the strain or the elastic modulus.
5. An ultrasonic imaging apparatus according to claim 4, wherein
the setting means assigns the hue information so as to display the
hard part of the region with blue and the soft part of the region
with red.
6. An ultrasonic imaging apparatus according to claim 4, wherein
the setting means assigns the hue information so as to display a
boundary portion between the color of the hard part and the color
of the soft part with green.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a Divisional of U.S. application Ser.
No.10/580,100, filed May 19, 2006, which claims priority from
Japanese Patent Application Nos. 2003-391997 and 2003-393305, filed
Nov. 21, 2003 and Nov. 25, 2003, respectively, the contents of
which are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to an ultrasonic imaging
apparatus that displays an ultrasound image of a diagnostic portion
of an object with ultrasonic waves. In particular, the present
invention relates to a technology for displaying an elastic image
with the strain of the tissue or an elastic modulus.
BACKGROUND ART
[0003] An ultrasonic imaging apparatus measures an ultrasonic
reflectance of the tissue in an object with ultrasonic waves. In
general, the ultrasonic imaging apparatus displays an ultrasound
image of the reflectance of a diagnostic portion with the measured
value, as luminance. Recently, in the ultrasonic imaging apparatus,
time-series images of the temporal change in the tissue are
obtained upon applying a pressure to the measured portion, the
correlation between the time-series images is obtained, the amount
of motion (e.g., displacement) of the tissue is obtained, the
strain of the tissue is measured by spatially differentiating the
amount of motion, and an elastic modulus of the tissue is measured
for tissue diagnosis. Further, the measured strain or the
distribution of elastic moduli is displayed as an elastic
image.
[0004] The elastic image, serving as the strain or the elastic
modulus, is displayed as a color image added with information on
the hue of red, blue, and the like, depending on the amount of
strain or the elastic modulus of the tissue. That is, the tumor
spread or tumor size is easily diagnosed by displaying an image
that is obtained by adding, mainly, a specific color to a hard
portion of the tissue. As disclosed in Patent Document 1 and Patent
Document 2, the elastic images, serving as color images, are
arranged on the same screen as that of a B-mode image, or are
overlaid to and are displayed on the B-mode image, as mentioned
above. In particular, Patent Document 2 proposes that the elastic
images are displayed by varying the luminance of red, blue or
another color, depending on the elastic modulus.
[0005] However, in the ultrasonic imaging apparatus disclosed in
Patent Document 2, the color assignment is not considered upon
setting the strain or the elastic modulus as color images. In
general, in order to display a physical quantity, such as the
distribution of temperatures, by varying the hue for the purpose of
easy understanding, the temperature within a display range from the
minimum value to the maximum value thereof is classified to a
plurality of segments. The colors from red to blue via a neutral
color corresponding to the segments are assigned by varying the hue
in view of tone.
[0006] The elastic image is used for diagnosing the tumor, such as
cancer. However, the shape and the hardness of the tumor, such as
the cancer, are varied depending on individuals, portions, and
medical conditions.
[0007] Therefore, the uniform fixing of the hue corresponding to
the level of strain or elastic modulus necessarily causes the
diagnosis of the portion size with a predetermined hardness or
more. Thus, the diagnosis takes a long time, the boundary of the
tumor cannot be easily identified, and there are above-mentioned
problems of deterioration in convenience. In particular, there is a
risk that it is impossible to accurately determine the range of the
affected part to be extirpated.
[0008] Patent Document 1: JP 5-317313A
[0009] Patent Document 2: JP 2000-60853A
DISCLOSURE OF INVENTION
[0010] It is an object of the present invention to improve the
convenience of use by displaying, with color segment, the level of
the elasticity, such as the strain of the tissue or the elastic
modulus depending on the interest of an examiner.
[0011] In order to solve the problems, according to the present
invention, an ultrasonic imaging apparatus comprises: an ultrasonic
probe that receives and sends ultrasonic waves from/to an object;
ultrasound image structuring means that generates an ultrasound
image on the basis of a reflected echo signal received by the
ultrasonic probe; elastic image structuring means that obtains a
physical quantity of the elasticity of the object of a region
corresponding to the ultrasound image on the basis of the reflected
echo signal and generates a color elastic image; display means that
overlays the ultrasound image to the color elastic image, or
arranges the ultrasound image and the color elastic image and
displays the resultant image on a screen; and input means that
variably sets a corresponding relationship between a hue of the
color elastic image displayed on the screen and the level of a
physical quantity.
[0012] Thus, a corresponding relationship between the hue and a
physical quantity of the color elastic image is variably set via
the input means on the basis of examinee determination, thereby
displaying the color elastic image by adding favorite easily-viewed
colors to the portions of the tissue with the elastic level, such
as desired strain or elastic modulus. That is, for a diagnostic
target, e.g., upon diagnosing the tumor, such as the cancer, it is
possible to display the region with desired hardness to be observed
with a specific color determined depending on the individual
difference or medical condition. As a consequence thereof, the
convenience of use such that the identification between the region
to be observed and the region not to be observed becomes easy, and
the diagnosis is fast can be improved.
[0013] In this case, preferably, the corresponding relationship
between the physical quantity and the hue of the color elastic
image set by the input means may be displayed with a color bar on
the screen.
[0014] Further, in the display operation with the color bar, a
large physical quantity and a small physical quantity can be
displayed with different hues and the boundary between the hue
having the large physical quantity and the hue having the small
physical quantity can be displayed with another hue. That is, a
boundary region with hardness to be observed by the examinee is
displayed with different color from that of another region on the
color elastic image and, therefore, a region of interest is
obviously displayed and the boundary region of the tissue, such as
the cancer, can be easily identified. Thus, the visibility can be
improved. In this case, preferably, the boundary between the hue
having the large physical quantity and the hue having the small
physical quantity may be movably formed with the input means. Thus,
the spread of the boundary region with hardness can be easily
observed.
[0015] Furthermore, the color elastic image can be displayed
alternatively a larger region or a smaller region than the setting
physical quantity with a set hue. In addition, the color elastic
image has a peripheral region including a setting value of the
physical quantity with the hue different from the hue of another
region. In this case, the hue of the peripheral region has a tone
in accordance with the level of the physical quantity. Thus, only a
portion with a hard region of interest or a portion with a soft
region of interest can be displayed with a color image.
[0016] Specifically, the elastic image structuring means comprises:
a color conversion table that is rewritable and sets a relationship
between the level of the physical quantity and the color of the
color elastic image; calculating means that a physical quantity of
the elasticity of the object of a region corresponding to the
ultrasound image on the basis of the reflected echo signal; color
image generating means that reads the color corresponding to the
obtained physical quantity from the conversion table and generates
a color elastic image indicating the distribution of physical
quantities; and input means that rewrites contents of the color
conversion table. Further, the elastic image structuring means
displays, on the screen, a color bar indicating a corresponding
relationship between the level of the physical quantity and the hue
of the color elastic image, set to the color conversion table.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a block diagram showing the entire structure of an
ultrasonic imaging apparatus according to embodiments of the
present invention.
[0018] FIG. 2 is a diagram showing the detailed structure of a
feature according to the present invention.
[0019] FIG. 3 is a diagram showing an example of a display
image.
[0020] FIG. 4 is an explanatory diagram of a corresponding
relationship between the distribution of strains and hue
information on a color conversion table according to the first
embodiment.
[0021] FIG. 5 is an explanatory diagram of a corresponding
relationship between the distribution of elastic moduli and hue
information on a color conversion table according to the second
embodiment.
[0022] FIG. 6 is a diagram showing examples of image display
operation according to the first and second embodiments.
[0023] FIG. 7 is an explanatory diagram of the correspondence
between hue information on a color conversion table and the display
operation with color bars according to the third embodiment.
[0024] FIG. 8 is an explanatory diagram of a corresponding
relationship between a color bar and hue information on a color
conversion table according to the fourth embodiment.
[0025] FIG. 9 is a diagram showing examples of image display
operation according to the fourth embodiment.
[0026] FIG. 10 is an explanatory diagram of a corresponding
relationship between a color bar and hue information on a color
conversion table according to the fifth embodiment.
[0027] FIG. 11 is an explanatory diagram of a corresponding
relationship between a color bar and hue information on a color
conversion table according to the sixth embodiment.
[0028] FIG. 12 is a diagram showing examples of image display
operation according to the sixth embodiment.
[0029] FIG. 13 is an explanatory diagram of a corresponding
relationship between a color bar and hue information on a color
conversion table according to the seventh embodiment.
BEST MODE FOR CARRYING OUT THE INVENTION
[0030] Hereinbelow, a specific description is given of embodiments
of the present invention with reference to the drawings.
[0031] FIG. 1 is block diagram showing the structure of an
ultrasonic imaging apparatus according to embodiments of the
present invention. Referring to FIG. 1, according to the
embodiments, an ultrasonic imaging apparatus comprises: a probe 2
that comes into contact with an object 1 and is thus used; a
transmitting circuit 3 that repeatedly sends ultrasonic waves to
the object 1 via the probe 2 at a predetermined time interval; a
receiving circuit 4 that receives reflected echo signals on time
series generated from the object 1; and a phasing and adding
circuit 5 that phases and adds the received reflected echoes and
generates RF signal data on time series. Further, the ultrasonic
imaging apparatus comprises: an ultrasound image structuring unit 6
that structures a shading tomographic image, e.g., a monochrome
tomographic image, of the object 1 on the basis of the RF signal
data output from the phasing and adding circuit 5; and an elastic
image structuring unit 7 that measures the displacement of the
tissue of the object 1 from the RF signal data of the phasing and
adding circuit 5, obtains elastic data, and structures a color
elastic image. Further, the ultrasonic imaging apparatus comprises:
a switching adder 8 that changes a rate between the monochrome
ultrasound image and the color elastic image and synthesizes the
images; and an image indicator 9 that displays the synthesized
images. The ultrasonic imaging apparatus shown in FIG. 1 is
properly operated by an external operator (examiner) via an
operating unit 17 and a control unit 18. Note that the signals
output from the phasing and adding circuit 5 can be signals I and Q
for combining and demodulating RF signal frame data, e.g., RF
signals.
[0032] The probe 2 comprises a plurality of vibrators, and has a
function for receiving and transmitting ultrasonic waves via the
vibrators to/from the object 1 with electronic beam-scanning. The
transmitting circuit 3 has a function for generating transmitting
pulses to generate ultrasonic waves by driving the probe 2, and for
setting the convergent point of the sent ultrasonic beams with an
arbitrary depth. The receiving circuit 4 generates an RF signal by
amplifying, with predetermined gain, the reflected echo signals
received by the probe 2. The phasing and adding circuit 5 controls
the phase by inputting the RF signal amplified by the receiving
circuit 4, forms ultrasonic beams converged at a plurality of
convergent points, and generates the RF signal data. In general,
upon measuring the elasticity of the tissue, the object 1 is
pressurized, the displacement of the diagnostic portion under the
pressurizing operation is measured, the strain and the elastic
modulus are calculated and the elastic image is generated. In the
pressurizing operation, the distribution of stress is effectively
applied to the body cavity of the diagnostic portion of the object
1 while the probe 2 receives and sends the ultrasonic waves.
Therefore, a pressurizing plate is uniformly attached to a
receiving and transmitting surface of the ultrasonic waves of the
probe 2, a pressurizing surface comprising the receiving and
transmitting surface of the ultrasonic waves and the pressurizing
plate of the probe 2 comes into contact with the body surface of
the object, the pressurizing surface is moved up and down, and the
object is pressed (pressurized and depressurized).
[0033] The ultrasound image structuring unit 6 comprises a signal
processing portion 10 and a monochrome scan converter 11. Herein,
the signal processing portion 10 inputs the RF signal data from the
phasing and adding circuit 5 and performs signal processing, e.g.,
gain correction, log compression, detection, edge enhancement, and
filtering processing, and obtains ultrasound image data. Further,
although not shown, the ultrasound image structuring unit 6
comprises: an ND converter that converts the ultrasound image data
from the monochrome scan converter 11 and the signal processing
portion 10 into a digital signal; a plurality of frame memories
that store a plurality of pieces of the converted ultrasound image
data on time series; and a controller. The monochrome scan
converter 11 obtains, as one image, ultrasound image frame data in
the object 1 stored in the frame memory, and reads the obtained
ultrasound image frame data synchronously to a TV signal. That is,
in order to obtain the RF signal frame data of the object including
the moving tissue at an ultrasonic period with the reflected echo
signals output from the signal processing portion 10 and to display
the RF signal frame data, the monochrome scan converter 11
comprises ultrasound image scanning means for reading the RF signal
frame data at a TV-signal period and means for controlling the
system.
[0034] The elastic image structuring unit 7 comprises: an RF signal
selecting portion 12; a displacement calculating portion 13; a
strain calculating portion 14; an elastic data processing portion
15; and a color scan converter 16. The color scan converter 16 is
connected to the operating unit 17 via the control portion 18, and
can control the hue of the elastic image from the operating unit
17. Herein, the operating unit 17 comprises operating equipment,
such as a keyboard, a track ball, and a mouse. Although not shown,
a pressure gauge is attached to the probe 2 having a pressure
measuring portion that measures a pressure (pressing force) for
pressing the probe 2 to the object 1.
[0035] The RF signal selecting portion 12 comprises a frame memory
and a selecting section. The RF signal selecting portion 12 stores,
to the frame memory, a plurality of pieces of the RF signal data
output from the phasing and adding circuit 5, and selects one set,
that is, two pieces of the RF signal frame data from the stored RF
signal frame data. For example, the RF signal selecting portion 12
sequentially assures, in the frame memory, the RF signal data on
time series generated on the basis of a frame rate of the image by
the phasing and adding circuit 5. In accordance with an instruction
of the control unit 18, the RF signal frame data (N)
currently-assured is selected by a selecting portion, as first
data. Simultaneously, one piece of the RF signal frame data (X) is
selected from the RF signal frame data (N-1, N-2, N-3, N-M) that
have been assured. Herein, reference symbols N, M, and X denote
index numbers which are natural numbers and are added to the RF
signal frame data.
[0036] The displacement calculating portion 13 obtains the
displacement of the tissue from one set of the RF signal frame
data. For example, the displacement calculating portion 13 performs
one-dimensional or two-dimensional correlation processing of one
set of the RF signal frame data (N) and (X) selected by the RF
signal selecting portion 12, and obtains the displacement or a
motion vector of the tissue corresponding to the ultrasound image,
that is, the distribution of one-dimensional or two-dimensional
displacement on the displacement direction and the amount of
displacement. Herein, a detecting method of the motion vector
includes a block matching method and a gradient method disclosed in
JP 5-317313A. Further, according to the block matching method, the
image is divided into blocks comprising N.times.N pixels, attention
is paid to the block within an interest region, the block that is
the most approximate to the block to which the attention is paid is
searched from the previous frames, and a sample value is determined
on the basis of the prediction coding, that is, the difference, by
referring to the searched block.
[0037] Herein, the strain data can be calculated by spatially
differentiating the amount of motion of the tissue, e.g., the
displacement. Further, the data on the elastic modulus can be
calculated by dividing the change in pressure by the change in
amount of motion. First, the strain calculating portion 14
calculates the strain data by spatially differentiating the amount
of motion of the tissue, e.g., the displacement, output from the
displacement calculating portion 13. Reference symbol .DELTA.L
denotes the displacement measured by the displacement calculating
portion 13, and reference symbol .DELTA.P denotes a pressure
measured by the pressure measuring portion (not shown). Since
strain S can be calculated by spatially differentiating .DELTA.L,
the strain S is obtained by an expression of S=.DELTA.L/.DELTA.X.
Herein, the pressure applied to the body surface can be directly
measured by a pressure sensor existing between the body surface and
the contact surface of a pressurizing mechanism, or can be measured
by a method disclosed in Japanese Patent Application No.
2003-300325 filed by the present application of the present
invention. Further, Young's modulus Ym of the elastic modulus data
is calculated by an expression of Ym=(.DELTA.P)/(.DELTA.L/L). Since
the elastic modulus of the tissue corresponding to the point on the
ultrasound image can be obtained from the Young's modulus, the
two-dimensional elastic image data can be continuously obtained.
Note that the Young's modulus is the ratio of a simple strain
applied to a substance to a strain caused in generated in parallel
with the strain. Note that the strain calculating portion 14 may
perform various image processing of the calculated elastic frame
data, including smoothing processing on the coordinate plane and
contrast optimizing processing, and smoothing processing in the
time-base direction between the frames, and may output the elastic
frame data after the processing, as the amount of strain.
[0038] The elastic data processing portion 15 comprises a frame
memory and an image processing section, assures the elastic frame
data output on time series from the strain calculating portion 14
to the frame memory, and performs the image processing of the
assured frame data with the image processing section in accordance
with an instruction of the control unit 18.
[0039] The color scan converter 16 converts the elastic frame data
from the elastic data processing portion 15 into hue information in
accordance with a color conversion table, which will be described
later. That is, the color scan converter 16 converts the elastic
frame data into the hue information comprising three primary colors
of light, i.e., color codes of R (Red), G (Green), and B (Blue).
For example, the color scan converter 16 converts the elastic data
with large strain into the red code and simultaneously converts the
elastic data with small strain into the blue code. Note that the
tones of R, G, and B are assigned to 256 steps, and a tone "256"
means the display operation with large luminance and, on the other
hand, a tone "0" means that the image is not displayed.
[0040] The switching adder 8 comprises: a frame memory; an image
processing section; and an image selecting section. Herein, the
frame memory stores ultrasound image data from the monochrome scan
converter 11 and elastic image data from the color scan converter
16. The image processing section adds and synthesizes the
ultrasound image data and the elastic image data assured in the
frame memory with a setting ratio in accordance with an instruction
from the control unit 18. Luminance information and hue information
of the pixels of the synthesized image is obtained by adding
information on the monochrome ultrasound image and information on
the color elastic image with the setting ratio. Further, the image
selection section selects an image to be displayed on the image
indicator 9 from the ultrasound image data and the elastic image
data in the frame memory and the synthesized image data in the
image processing section in accordance with an instruction from the
control unit 18. Note that the ultrasound image and the elastic
image may be individually displayed without synthesis.
[0041] Next, a description is given of the operation of the
ultrasonic imaging apparatus with the above-mentioned structure. In
the ultrasonic imaging apparatus 1, the transmitting circuit 3
repeatedly sends ultrasonic waves to the object 1 via the probe 2
that comes into contact with the object 1 at the time interval, the
receiving circuit 4 receives the reflected echo signals on time
series generated from the object 1, and the RF signal data is
generated by phasing and addition. The ultrasound image structuring
unit 6 generates a shading tomographic image, e.g., a monochrome
B-mode image on the basis of the RF signal data. In this case, the
scanning operation in a predetermined direction is performed with
the probe 2, thereby obtaining one ultrasound image. The elastic
image structuring unit 7 generates a color elastic image on the
basis of the RF signal data that is phased and added by the phasing
and adding circuit 5. The switching adder 8 adds the obtained
monochrome ultrasound image and the color elastic image and
generates the synthesized image thereof.
[0042] Herein, a description is given of an example of processing
of the switching adder 8 according to the embodiments. Hereinbelow,
the ultrasound image data input to the ultrasound image structuring
unit 6 is ultrasound image data i, j and ultrasound image data
input to the elastic image structuring unit 7 is elastic image data
i,j. Subscripts i and j denote coordinates of data components. As
mentioned above, the ultrasound image data and the elastic image
data include the luminance information and the coordinate
information, corresponding to the image display operation.
[0043] First, the ultrasound image data having monochrome luminance
information is converted into the hue information. When the
ultrasound image data after conversion has the same bit length as
that of the monochrome luminance information, hue data of the
converted ultrasound image data, i.e., three primary-color (R, G,
B) data of light can be expressed by the following Expression
1.
(Expression 1)
(Ultrasound image data R) i,j=(Ultrasound image data) i, j
(Ultrasound image data G) i,j=(Ultrasound image data) i, j
(Ultrasound image data B) i,j=(Ultrasound image data) i, j
[0044] Subsequently, the converted ultrasound image data and the
elastic image data are added with a setting ratio a for synthesis.
Herein, the setting ratio a is arbitrarily set in advance in
accordance with the characteristic of the tissue and a relationship
of 1<.alpha.<1 is established. With the setting ratio a, the
synthesized image is generated as shown by the following Expression
2. The synthesized image is arbitrarily selected and is displayed
on the image indicator 9.
(Expression 2)
(Synthesized data R) i,j=(1-.alpha.).times.(ultrasound image data
R) i,j+.alpha.X(elastic image data R) i,j
(Synthesized data G)i,j=(1-.alpha.).times.(ultrasound image data
G)i,j+.alpha.X(elastic image data G)i,j
(Synthesized data B)i,j=(1-.alpha.).times.(ultrasound image data
B)i,j+.alpha.X(elastic image data B)i,j
[0045] A description is given of the above-synthesized image with
reference to FIG. 3. FIG. 3 is a diagram showing a display example
of the ultrasound image, the elastic image, and the synthesized
image according to the embodiments. An image obtained by
superimposing the color elastic image to the monochrome ultrasound
image is displayed, and an image obtained by synthesizing the
monochrome ultrasound image and the color elastic image by the
switching adder 8 is displayed.
[0046] Upon obtaining the elastic image, a region of interest (ROI)
50 for determining a range for obtaining the elastic image on the
monochrome ultrasound image is set, and the elastic image of the
ROI 50 is obtained. The ROI 50 is set because a region for
obtaining the elastic image is limited to the depth direction and
even when a wide region is obtained, the possibility of a large
part of regions having noise is high. The ROI 50 can be arbitrarily
set mainly in the pressing direction of the probe to the object in
accordance with an instruction from the operating unit 17.
[0047] Herein, a detailed description is given of portions, serving
as the feature according to the present invention with reference to
FIG. 2. The color scan converter 16 outputs, to the switching adder
8, strain data output from the elastic image data processing unit
or the data on the elastic modulus, as the elastic image data
including the information on the converted three primary colors.
Referring to FIG. 2, the color scan converter 16 comprises, as the
detailed structure: a 256-tone portion 20 that assigns the data to
three primary colors on the basis of the strain data or the data on
the elastic modulus; a boundary line control portion 22 that
switches a color range and changes a boundary portion in accordance
with an instruction from the operating unit 17; a color mapping
portion 21 that creates a color map matching the image from the
256-tone portion 20 and the boundary line control portion 22; and
an image data output portion 24 that outputs the image data from
the color mapping portion 21 to the switching adder 8. In order to
assign the elastic frame data, i.e., the amount of strain,
corresponding to the pixel output from the elastic data processing
portion 15 to 256 tones, the 256-tone portion 20 sets the data to a
signal with the structure of 8 bits under a matching rule, and
outputs the tone data of (256 tones) with the structure of 8 bits
to the color mapping portion 21. The color mapping portion 21
inputs the tone data of (256 tones) with the structure of 8 bits
output from the 256-tone portion 20, and adds the hue information
of red, green, and blue to the tone data in accordance with the
color conversion table corresponding to color bars that are
preset.
[0048] Next, a description is given of the color scan converter
that displays the color elastic image according to the
embodiments.
FIRST EMBODIMENT
[0049] According to the first embodiment, a case of displaying the
strain with colors will be described. First, the strain data S is
obtained every frame on the basis of S=.DELTA.L/.DELTA.X, and
statistical processing of the strain in the ROI 50 is performed.
FIG. 4 is a graph with the abscissa, serving as frequency, and the
ordinate, serving as strain and, in the statistical processing, the
strains corresponding to strains in the ROI 50 are distributed on
the graph shown in FIG. 4, the strains are added, and the total
amount of strains is calculated. An average 30 of the strains is
calculated by calculation of (the total amount of strain)/(the
number of pixels). Colors are assigned in accordance with the
fractions from a maximum strain value to a minimum strain value
based on the average 30 of the strains. Specifically, the hue
information comprising color codes of red (R), green (G), and blue
(B) is assigned to table coordinates corresponding to strain values
of the color conversion table 31 of the hue information stored in
the memory provided for the color scan converter 16.
[0050] In the case of assigning the colors, upon displaying a soft
region with a large strain with red, the red R color code, to be
assigned to the coordinate corresponding to the region with large
strain in the color conversion table 31 shown in FIG. 4(a), is set
to be large. The green G and blue B are set to be small. Thus, the
elastic image data is generated on the basis of the color
conversion table 31, thereby displaying the soft region with red.
On the other hand, upon displaying a hard region with small strain
with blue, the blue B color code, to be assigned to the coordinate
corresponding to the region with small strain in the color
conversion table 31, is set to be large. The green G and red R are
set to be small.
[0051] When a hard region widely exists in the ROI 50 and the hard
region is entirely to be grasped, the color codes are set for clear
display operation by extending the range of blue B in the
assignment of red R, green G, and blue B relative to the strain
values in the color conversion table 31 shown in FIG. 4. Further,
in order to clearly display the boundary portion 32 between the
hard region and the soft region, an instruction is input to the
boundary line control portion 22 form the operating unit 17,
thereby setting the boundary portion 32 between the red R and blue
B to green G. Furthermore, in order to display the hard region with
blue B and the soft region with red R on the basis of the average
30 of the strain as center, the hue information in the color
conversion table 31 is assigned. The elastic image data is
generated and is displayed on the basis of the assignment. Thus,
referring to FIG. 6(a), it is possible to widely identify where the
hard tissue exists. Note that a broken line 100 shown in FIG. 6 is
not displayed on the elastic image and is used to describe a
corresponding relationship among FIGS. 6(a), (b), and (c). Further,
reference symbol 102 denotes the soft region, reference symbol 103
denotes the hard region, and reference symbol 101 denotes a region
with an average hardness.
[0052] On the other hand, when the soft region exists in the ROI 50
and the soft region is entirely to be grasped, in order to clearly
display the red R, the red R, green G, and blue B are assigned to
the coordinates corresponding to the region with small strain in
the color conversion table 31 shown in FIG. 4. In order to clearly
display the boundary portion 32 between the hard region and the
soft region, an instruction is input to the boundary line control
portion 22 from the operating unit 17, and the boundary portion 32
between the red R and the blue B is set to the green G. The color
conversion table 31 is set by narrowing a display range of red R so
as to display the soft range with red R and widely display the blue
B. The elastic image data is generated and is displayed on the
basis of the assignment, thereby widely displaying the blue B as
shown in FIG. 6(b) and using the blue B, as the background of the
red R. Thus, the red R to be extracted can be obviously displayed
and it is possible to easily identify where the soft tissue
exists.
[0053] Further, when the hard region exists in the ROI 50 and is to
be grasped, referring to FIG. 4(c), the red R, the green G, and the
blue B are variably assigned to the strain in the color conversion
table 31 so that blue B is obviously displayed. First, in order to
clearly display the boundary portion 32 between the hard region and
the soft region, an instruction is input to the boundary line
control portion 22 form the operating unit 17, and the boundary
portion 32 between the red R and the blue B is set. Further, the
color conversion table 31 is set by narrowing a display range of
the blue B and widely display the red R so as to display the hard
region with the blue B. The elastic image data is generated and is
displayed on the basis of the assignment, thereby widely displaying
the red R as shown in FIG. 6(c) and using the red R, as the
background of the blue B. The blue B to be extracted can be
obviously displayed and it is possible to easily identify where the
hard region exists.
[0054] As mentioned above, according to the first embodiment, the
region with strain to be extracted can be obviously displayed by
moving the boundary portion 32 between one soft region and the
other hard region sandwiched by the boundary portion 32.
SECOND EMBODIMENT
[0055] According to the second embodiment, a description is given
of the case of displaying the elastic modulus with colors. Unlike
the first embodiment, the elastic modulus is assigned, in place of
the strain. The elastic modulus (Young's modulus) Ym is calculated
by the expression of Ym=(.DELTA.P)/(.DELTA.L/L). Referring to FIG.
5, in the color conversion table 31 provided for the color
converter 16, the range of calculating values of the elastic
modulus is divided into a plurality of sections, and the color
codes of red R, green G, and blue B are set to the sections. The
hue information corresponding to the calculating value of the
elastic modulus to be input is read from the color conversion table
31 and the elastic image data is generated.
[0056] Herein, when the elastic modulus is widely identified in the
ROI 50, referring to FIG. 5(a), an instruction is input to the
boundary line control unit 22 from the operating unit 17, similarly
to the first embodiment. Further, the boundary portion 32 between
the red R and the blue B is set to green G. Furthermore, the color
conversion table 31 is set so as to display the region with low
elastic modulus with the blue B and the region with high elastic
modulus with the red R on the basis of the average value of the
elastic modulus as center. The elastic image data is generated and
is displayed on the basis of the assignment. With the display
operation, it is possible to widely identify where the region with
high elastic modulus or low one exists.
[0057] When the region with high elastic modulus is to be
identified in the ROI 50, referring to FIG. 5(b), an instruction is
input to the boundary line control portion 22 from the operating
unit 17 similarly to the first embodiment, and the boundary portion
32 between the red R and the blue B is set to the green G. Further,
the color conversion table 31 is set so that the region with low
elastic modulus is displayed with the blue B and the region with
high elastic modulus is displayed with the red R on the basis of
the region with high elastic modulus as center. The elastic image
data is generated and is displayed on the basis of the assignment.
With the display operation, it is possible to identify where the
tissue with high elastic modulus exists.
[0058] Further, when the region with low elastic modulus is to be
identified in the ROI 50, referring to FIG. 5(c), an instruction is
input to the boundary line control portion 22 from the operating
unit 17 similarly to the first embodiment, and the boundary portion
32 between the red R and the blue B is set to the green G. Further,
the color conversion table 31 is set so that the region with low
elastic modulus is displayed with the blue B and the region with
high elastic modulus is displayed with the red R on the basis of
the region with low elastic modulus as center. The elastic image
data is generated and is displayed on the basis of the assignment.
With the display operation, it is possible to identify where the
tissue with low elastic modulus exists.
[0059] As mentioned above, according to the second embodiment, the
region to be extracted with elastic modulus can be obviously
displayed by moving the boundary portion 32 between one region with
high elastic modulus and the other region with low elastic modulus
sandwiched by the boundary portion 32.
THIRD EMBODIMENT
[0060] According to the third embodiment, a description is given of
the case of displaying only a desired region with strain or elastic
modulus. Unlike the first and second embodiments, the assignment of
the hue information in the color conversion table 31 is changed so
as to prevent the display operation of a neutral portion 33. An
instruction is input to the boundary line control portion 22 from
the operating unit 17 and the hue information in the color
conversion table 31 is changed, thereby extracting only a hard
region and a soft region with desired strain and only a region with
high elastic modulus and a region with low elastic modulus. As
mentioned above, non-display operation of the neutral portion
enables data without needing the elastic image to be removed and
further enables the elastic image to be displayed with the removal
of noise in the unnecessary data. Note that the boundary portion 32
may be arbitrarily moved in the vertical direction by operating the
operating unit 17 or the display range may be widened. Further, it
is possible to display one of the hard region and the soft region
with strain or to display one of the region with high elastic
modulus and the region with low elastic modulus.
[0061] According to the first to third embodiments, the soft region
is displayed with the red R and the hard region is displayed with
the blue B on the basis of the amount of strain. However, it is
obvious that the region may be displayed with any color,
irrespective of the above colors. This can be applied to the
elastic modulus. Specifically, the 256-tone portion 20 may
arbitrarily set the shading of color or may replace the shading of
scale with a complex color obtained by combining red R, green G,
and blue B, e.g., black, yellow, or pink, thereby displaying a
color for easily identifying the soft region or the hard region by
an examiner.
[0062] Similarly, the boundary portion 32 may be displayed by
replacing the above colors including the green G with a neutral
color of the red R and the blue B or a complex color obtained by
combining the red R and the green G. Further, when the color of the
hard region is different from that of the soft region, the boundary
is clear. Therefore, an instruction may be inputted to the boundary
line control portion 22 from the control unit 17 to control the
switching operation f colors without displaying the boundary
portion 32.
FOURTH EMBODIMENT
[0063] FIG. 8 shows a color bar 41 indicating a relationship
between the tone data and the hue information according to the
fourth embodiment and a color conversion table 42 of the hue
information corresponding to the color bar 41. Unlike the first to
third embodiments, in place of the display operation of the level
of the strain or the elastic module with the two colors including
the red R and the blue B, the coloring operation is performed with
three colors of red R, green G, and blue B. Further, according to
the fourth embodiment, the boundary portion with the level of the
strain or the level of the elastic modulus is not displayed.
[0064] That is, referring to FIG. 8, in the tone data in the color
conversion table 42, the hue information is assigned so as to
convert the soft region with the measured large strain into to the
color code of the red R, the hue information is assigned so as to
convert the hard region with the measured small strain into the
color code of the blue B, and the hue information is assigned so as
to convert the region with middle strain into the color code of the
green G. Therefore, the interval between the color codes of the red
R and the green G is converted into Ye (Yellow), the interval
between the color codes of the green G and the blue B is converted
into Cy (Cyanogen), and the hue stepwise changes at the boundary
portion between the colors. However, the color conversion table
shown in FIG. 8 shows only typical color codes of the color bar 41.
Therefore, actually, the color code is assigned to be stepwise
changed at the boundary portion of colors.
[0065] The switching adder 8 inputs the monochrome ultrasound image
data from the monochrome scan converter 11 and the color elastic
image data from the color scan converter 16, and adds or switches
both the images. Herein, the switching adder 8 outputs only the
monochrome ultrasound image data or the color elastic image data,
or outputs resultant image data obtained by adding and synthesizing
both the image data, that is, can variously switch the output
operation. According to the fourth embodiment, upon adding and
synthesizing both the image data, the switching adder 8 can overlay
the color elastic image data to the monochrome B-mode ultrasound
image data with predetermined transparency and can display the
resultant image data on the image display 9.
[0066] FIG. 9 is a diagram showing a display example of the image
indicator 9 in the ultrasonic imaging apparatus according to the
fourth embodiment. Referring to FIG. 9, an elastic image with
transparency "0" is displayed. As shown in FIG. 9, a rectangular
gray region (gray region lighter than the periphery) displayed
around the center of the display image is the region ROI of
interest. A circular dark gray region in the rectangular interest
region is the hard region, as the tissue. The light gray region
other than the dark gray region is a relatively soft region. The
rectangular interest region is actually displayed with a color.
Since the rectangular interest region is displayed with monochrome
colors in FIG. 9, the identification is not easy. However, the
light gray region in the interest region is green, and the circular
dark gray region is entirely blue. Note that the dark gray region
in a region surrounded by a dotted circle is red and a region
except for the above-mentioned dark gray region is blue in FIG. 9.
In these cases, the red indicates the soft region of the tissue,
the blue indicates the hard region, and the green indicates a
region with middle hardness between the hard region and the soft
region.
[0067] As mentioned above, the hardness of the tissue can be easily
viewed by displaying the strain elastic image in the interest
region with the colors in accordance with the hardness of the
region. In particular, according to the fourth embodiment, it is
possible to arbitrarily change the hue information of the color
conversion table 42 in the color mapping portion 20 in the color
scan converter 16 via the operating unit 17. Therefore, the
examiner varies the hue information in the color conversion table
42 for the purpose of the diagnosis, thereby adjusting the coloring
operation so as to display a region with predetermined hardness or
more with the blue. As a consequence thereof, the visibility is
improved and the convenience of use is further improved.
[0068] Conventionally, the hue information in the color conversion
table 42 is uniformly fixed in accordance with the level of the
strain or the elastic modulus. Therefore, upon diagnosing the size
of a region with predetermined hardness or more or upon diagnosing
the spread thereof, the region with predetermined hardness or more
cannot be intuitively determined. On the contrary, according to the
fourth embodiment, since the examiner can freely change the hue
information in the color conversion table 42, the region with
predetermined hardness or more or the spread thereof can be easily
diagnosed.
[0069] Further, referring to FIG. 9, the right side of the elastic
image displays the color bar 41 indicating the hardness of the
elastic image. The color bar 41 is the same as that shown in FIG.
8. Although the color bar 41 is displayed with monochrome colors,
the color bar 41 is actually displayed with colors in accordance
with the hue information shown in the color conversion table 42 in
FIG. 8 on the display screen. On the top and bottom of the color
bar 41, characters "Soft" and "Hard" are displayed so as to easily
identify the assignment of color and hardness. This display
operation is performed because the color bar 41 corresponds to the
level of strain, that is, the hardness and softness of the tissue.
Therefore, when the color bar 41 corresponds to the amount of
displacement, a character indicating the distance is displayed.
Further, when the color bar 41 corresponds to the elastic modulus,
a character indicating the unit of elastic modulus is displayed.
Thus, the assignment relationship can be easily identified.
FIFTH EMBODIMENT
[0070] FIG. 10 shows a color bar and a color conversion table
according to the fifth embodiment. The color bar 41 according to
the fifth embodiment is an example of setting the hue information
so as to specifically observe the boundary of the hard region. That
is, FIG. 10 shows an example in which a hue with a tone, different
from peripheral hues with tones, is set to the intermediate region
between a color code of the blue B and a color code of the cyan Cy
in FIG. 8, serving as the boundary portion of the hard region,
thereby easily identifying the intermediate region. Further, the
hue at the intermediate region can stepwise be changed. Referring
to FIG. 10, Mg (Magenta) color is assigned to a region of the hue
which stepwise changes. The hue information of the color bar 41 is
set by assigning color codes (R, G, B) in the color conversion
table 42 via the operating unit 17. As shown in FIG. 10, color
codes, e.g., Magenta: (255, 0, 255), Violet (238, 130, 238), and
Plum (221, 160, 221) for stepwise changing the colors are assigned
so that the color code of Magenta Mg stepwise change. Similarly to
that shown in FIG. 8, the color bar 41 has the hue that stepwise
changes near the boundary of the colors. However, referring to FIG.
10, the color conversion table 42 indicated right-adjacent to the
color bar 41 shows only typical color codes. Therefore, the color
codes that stepwise change are assigned near the boundary of the
colors.
SIXTH EMBODIMENT
[0071] The example is given of assigning the color codes that
stepwise change near the boundary of the colors according to the
fifth embodiment. However, the present invention is not limited to
this. That is, according to the sixth embodiment, referring to FIG.
11, a region with desired hardness is over-colored with a color
code of Pink so as to emphasize only a region with interest
hardness (or softness). Further, only the elastic image of the
over-colored region is displayed with a pink color. The hue
information is set by assigning the color codes (R, G, B) in the
color conversion table 42 via the operating unit 17.
[0072] Herein, the over-colored region of the color code according
to the fifth or sixth embodiment as shown in FIG. 10 or 11 can be
freely expanded and can be freely moved, and can be freely set with
colors by inputting an instruction to the boundary line control
portion 22 from the operating unit 17 and varying the color
conversion table 42. Thus, it is possible to display, with favorite
colors, the region with desired hardness to be specifically
observed, or to stepwise display the region with colors. Thus, the
visibility is improved. Note that the number of a region that
partly has different colors is one or plural.
SEVENTH EMBODIMENT
[0073] FIGS. 12 and 13 show the color bar 41 and the color
conversion table 42 according to the seventh embodiment. The color
bar 41 according to the seventh embodiment is obtained by assigning
the hue information to one portion of 256 tones. FIG. 13 is a
diagram showing the details of the color bar 41 and the color
conversion table 42. The color bar 41 according to the seventh
embodiment is obtained by changing the color conversion table 42
from the operating unit 17 so that the hue information is added
only to the region with desired hardness, null data is stored to a
region other than the region with desired hardness, and the hue
information is not added to the region other than the region with
desired harness. As mentioned above, in order to specifically
display a region of high interest, the color bar 41 shown in FIG. 8
is compressed and the hue information is assigned only to the
region with hardness of high interest. The region having the
assigned null data becomes the elastic image with transparency of
100%. Note that the color bar 41 may be compressed as shown in FIG.
10 or 11 and, alternatively, a single color may be assigned. As a
consequence thereof, the hue information can be added only to a
region to be specifically observed, the visibility can be
improved.
[0074] According to the first to seventh embodiments, the
components of the frame data of the elasticity and the hue have
been described with the RGB-signal system. However, the present
invention is not limited to this and the hue information may be
added with another signal system (e.g., YUV-signal system).
[0075] Further, according to the first to seventh embodiments, the
assignment of color codes of red R, green G, and blue B in the
color conversion tables 31 and 41 is arbitrarily varied depending
on the strain or the elastic modulus. Thus, the elastic information
on the tissue, such as a soft or hard region and the level of the
elastic modulus, can be displayed for easy identification in
accordance with examiner's desire.
* * * * *