JPH114824A - Method for forming image by projecting minimum value and ultrasonic image pick-up device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a minimum-value-projecting image forming method and an ultrasonic image pick-up device, whereby a three-dimensional display image which depicts images of a blood vessel and a tumor together is obtained. SOLUTION: Image data in a three-dimensional area of interest in a three- dimensional coordinate space 146 wherein B-mode image data exist are converted to a minimum value, and minimum value projection is performed by an image processor 148 as to the B-mode image data in the three-dimensional coordinate space involving the area of interest in which the image data are converted to the minimum value, and an image is formed according to the image data on which the minimum value is projected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a minimum projection image forming method and an ultrasonic imaging apparatus, and more particularly to a minimum projection image for obtaining a three-dimensional display image by projecting minimum image data in a three-dimensional coordinate space. The present invention relates to a forming method and an ultrasonic imaging apparatus for obtaining a three-dimensional display image by minimum value projection.

[0002]

2. Description of the Related Art When a three-dimensional region in a subject is scanned with ultrasonic waves and a B-mode image of the region is captured based on an intensity signal of an echo, B-mode image data in a three-dimensional coordinate space is obtained. Minimum intensity projectio (MIP)
It is known that an approximate three-dimensional display image of a blood vessel image or the like can be obtained by performing the processing.

[0003]

SUMMARY OF THE INVENTION In a B-mode image,
For example, an image of a tumor or the like can be visually distinguished from an image of a surrounding normal tissue by differences in luminance, texture, etc., but its pixel value is not necessarily smaller than that of a normal tissue. It is not rendered with minimum intensity projection. In diagnosing a tumor, it is important to obtain a three-dimensional display image indicating a relative positional relationship with a blood vessel. In a three-dimensional display image obtained by projecting a minimum value of a B-mode image, a blood vessel image and a tumor image are combined. It is inconvenient because it cannot be drawn.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for forming a minimum intensity projection image for obtaining a three-dimensional display image in which a blood vessel image and a tumor image are simultaneously drawn, and an ultrasonic imaging method. The realization of the device.

[0005]

[Means for Solving the Problems]

(1) A first aspect of the present invention for solving the above-mentioned problem is that the image data in the three-dimensional region of interest in the three-dimensional coordinate space where the B-mode image data exists is minimized, and the three-dimensional image data is minimized. Minimum value projection is performed on the B mode image data in the three-dimensional coordinate space including the three-dimensional region of interest, and an image is formed based on the minimum value projected image data.

(2) According to a second aspect of the present invention, an ultrasonic transmitting / receiving means for scanning a three-dimensional region in a subject with ultrasonic waves and receiving the echoes, and a method for transmitting the echoes based on intensity signals of the echoes. B-mode image data generating means for generating B-mode image data representing a B-mode image in the subject, and minimizing image data in a three-dimensional region of interest in a three-dimensional coordinate space where the B-mode image data exists. Minimum value means for performing minimum value projection on B-mode image data in the three-dimensional coordinate space including the three-dimensional region of interest in which image data is minimized; Image forming means for forming an image based on the obtained image data.

[0007] In the first invention or the second invention, it is preferable that the three-dimensional region of interest is an elliptical laminate in order to simplify setting of the three-dimensional region of interest. (Operation) In the first invention or the second invention, the image of the three-dimensional region of interest is projected in the minimum value in addition to the blood vessel image by minimizing the image data in the three-dimensional region of interest. Therefore, by setting the range of the tumor portion observed on the B-mode image as a three-dimensional region of interest, the blood vessel image and the tumor portion image are displayed together.
A two-dimensional display image is obtained.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiment.

FIG. 1 is a block diagram of an ultrasonic imaging apparatus.
The figure is shown. This device is an example of an embodiment of the present invention.
The configuration of the present apparatus shows an example of an embodiment relating to the apparatus of the present invention. An example of an embodiment of the method of the present invention is shown by the operation of the present apparatus.

(Configuration) The configuration of the present apparatus will be described. As shown in FIG. 1, the present apparatus has an ultrasonic probe (probe) 2. The ultrasonic probe 2 has an array of a plurality of ultrasonic transducers (not shown). The array may be, for example, one along a forwardly projecting arc.
It is constituted by 128 ultrasonic transducers arranged in a dimension.

That is, the ultrasonic probe 2 is a convex probe. The ultrasonic probe 2 is not limited to a convex probe. Each ultrasonic transducer is made of a piezoelectric material such as PZT (lead zirconate titanate) ceramics. The ultrasonic probe 2 is used in contact with the subject 4.

The ultrasonic probe 2 is connected to a transmitting / receiving unit 6. The ultrasonic probe 2 and the transmission / reception unit 6 are an example of an embodiment of an ultrasonic transmission / reception unit in the present invention. The transmission / reception unit 6 transmits a driving signal to the ultrasonic probe 2 to transmit ultrasonic waves into the subject 4. The ultrasonic waves are transmitted as a beam into the subject 4. The transmission of the ultrasonic beam is repeatedly performed at predetermined time intervals.

The transmitting direction of the ultrasonic beam is sequentially changed,
The inside of the subject 4 is scanned by a sound ray formed by the ultrasonic beam. That is, the inside of the subject 4 is scanned in a sound ray sequence. The formation of a sound ray is performed by using a phased array (pha
sed array). In addition, scanning of sound rays is performed using an electronic scanning (scan) technique of sequentially moving a transmission aperture (aperture) along an array by switching a plurality of ultrasonic transducers involved in sound ray formation. .

The transmitting / receiving section 6 receives an echo signal from the subject 4 which is received by the ultrasonic probe 2. The reception of the echo signal is performed during the repetition of the transmission of the ultrasonic wave. Each reception forms an echo reception signal for each sound ray. The receiving sound ray is also scanned according to the transmission.

The formation of an echo reception signal for each sound ray is performed by, for example, a phased array technique for adjusting a time difference for adding reception signals of a plurality of ultrasonic transducers in the array. Scanning of the received sound ray is performed by electronic scanning that sequentially moves the received aperture along the array.

The scanning as shown in FIG. 2 is performed by the ultrasonic probe 2 and the transmitting / receiving unit 6. That is, as shown in the figure, when the sound ray 202 emitted from the radiation point 200 moves on the circular arc 204, the fan-shaped two-dimensional area 206 is scanned, and so-called convex scanning is performed. This scan is a θ scan. When the sound ray 202 is extended in the direction opposite to the transmission direction of the ultrasonic wave, all the sound rays intersect at one point 208. Point 208 is a divergence point of all sound rays.

The ultrasonic probe 2 is an actuator (actua).
tor) 8. The actuator 8 moves the ultrasonic probe 2 in a direction (φ direction) orthogonal to the θ scanning direction. That is, the actuator 8 performs φ scanning. The φ scan is performed in cooperation with the θ scan. For example, one φ scan is performed for each θ scan.
The pitch is advanced.

When .phi. Scanning is performed by swinging the ultrasonic probe 2, the center axis thereof passes through the diverging point 208 of the .theta. Scanning sound ray as shown by the center axis 300 in FIG. The combination of the φ scan and the θ scan scans the three-dimensional area 302 inside the subject 4. The φ scan may be performed as shown in FIG. In the φ scan shown in FIG. 4, the ultrasonic probe 2 is moved in parallel in a direction orthogonal to the θ scan. The φ scan may not necessarily be performed by the actuator 8 but may be manually performed by an operator.

An echo reception signal for each sound ray output from the transmission / reception unit 6 is input to a B-mode processing unit 10. The B-mode processing unit 10 forms B-mode image data. The B-mode processing unit 10 includes a logarithmic amplifier circuit 102 and an envelope detection circuit 104 as shown in FIG. The B-mode processing unit 10 logarithmically amplifies the echo reception signal by the logarithmic amplifier circuit 102, performs envelope detection by the envelope detection circuit 104, and indicates a signal representing the intensity of the echo at each reflection point on the sound ray;
That is, an A-scope signal is obtained, and B-mode image data is formed using the instantaneous amplitude of the A-scope signal as a luminance value.

The B-mode processing unit 10 is connected to the image processing unit 14. B-mode processing unit 10 and image processing unit 14
Is an example of an embodiment of a B-mode image data generating unit according to the present invention. The image processing unit 14 generates a B-mode image based on data input from the B-mode processing unit 10.

The image processing unit 14 includes a sound ray data memory 1 connected by a bus 140, as shown in FIG.
42, digital scan converter
converter) 144, an image memory 146, and an image processor 148. The B-mode image data input from the B-mode processing unit 10 for each sound ray is stored in the sound ray data memory 142.

When the scanning of the subject 4 is performed three-dimensionally, the sound ray data memory 142 stores three-dimensional sound ray data. That is, in the sound ray data memory 142, for example, a three-dimensional sound ray data space as shown in FIG. 7 is formed. This sound ray data space has three coordinate axes θ, φ, and z. These are polar coordinate axes.

Digital Scan Converter 144
Is for converting data in a sound ray data space into data in a physical space by scan conversion. Thus, the sound ray data space is converted into a physical data space as shown in FIG. 8, for example. This physical data space has three orthogonal coordinate axes of X, Y, and Z. The physical data space is shown in FIG. 3 or FIG.
Corresponds to the three-dimensional area 302 shown in FIG.

The image data converted by the digital scan converter 144 is stored in the image memory 146. That is, the image memory 146 stores the image data of the physical space. A three-dimensional coordinate space (data space) is formed in the image memory 146.

The image processor 148 performs predetermined data processing on the data in the sound ray data memory 142 and the image memory 146, respectively. This data processing includes data processing for obtaining a three-dimensional display image. The details of the data processing will be described later.

The image processor 148 is an embodiment of the minimizing means in the present invention. Moreover, it is an example of the embodiment of the minimum value projection means in the present invention. Further, it is an example of an embodiment of an image forming unit in the present invention.

A display unit 16 is connected to the image processing unit 14. The display unit 16 is provided with an image signal from the image processing unit 14 and displays an image based on the image signal.

The transmission / reception section 6, actuator 8, B
The mode processing unit 10, the image processing unit 14, and the display unit 16 are connected to the control unit 18. The control unit 18 supplies a control signal to each unit to control its operation.

An operation unit 20 is connected to the control unit 18. The operation unit 20 is operated by the operator, and the control unit 18
A desired command or information is input to the device. The operation unit 20 includes, for example, an operation panel provided with a keyboard and other operation tools.

(Operation) The operation of the present apparatus will be described. The operator positions the ultrasonic probe 2 connected to the actuator 8 at a desired position on the subject 4 and operates the operation unit 20 to perform an imaging operation. Hereinafter, the operation of the present apparatus is performed under the control of the control unit 18.

The transmitting / receiving unit 6 scans the inside of the subject 4 by θ through the ultrasonic probe 2 in the order of sound rays and receives the echoes one by one. The B-mode processing unit 10 obtains an A-scope signal from the echo reception signal input from the transmission / reception unit 6, and forms B-mode image data for each sound ray with each instantaneous value as a luminance value.

The image processing section 14 stores B-mode image data for each sound ray input from the B-mode processing section 10 in a sound ray data memory 142. As a result, a sound ray data space for the B-mode image data is formed in the sound ray data memory 142.

The image processor 148 scan-converts the B-mode image data in the sound ray data memory 142 with the digital scan converter 144, and converts the B-mode image data into the image memory 146.
Write to.

The read signal from the image memory 146 is transmitted to the display unit 16.
Will be displayed. As a result, a B-mode image is displayed. As the φ of the ultrasonic probe 2 scans, images of a plurality of cross sections (θ scan planes) 900 to 910 different in the φ direction are sequentially displayed, for example, as conceptually shown in FIG. 9. The image of each section is stored in the image memory 146. Thus, the image memory 146 stores an image related to the three-dimensional region 302 formed by stacking the cross sections 900 to 910.

The three-dimensional area 302 includes a blood vessel 920 and a tumor 9
22 are present. One end 924 of the tumor 922 is cross-sectional 90
It is located at 0. The thickest middle portion 926 of the tumor 922 is located at section 906. The other end 928 of the tumor 922 is located at section 910.

The operator observes the image of each section sequentially displayed on the display unit 16 to grasp the entire image of the tumor 922.
That is, the image of the cross section 906 is observed to recognize the thickest intermediate portion 926 of the tumor 922, and the images of the cross sections 900 and 910 are observed to recognize both end portions 924 and 928 of the tumor 922.

In obtaining a three-dimensional display image in the range of the cross sections 900 to 910, the operator operates the operation unit 20 on the screen of the cross section 906 on which the thickest middle portion 926 of the tumor 922 is displayed. Draw an outline. The outline is drawn using, for example, a variable elliptical figure whose shape and size can be adjusted by the operation unit 20. This is preferable in that an approximate contour is simply drawn.

For example, since a cross section of a tumor such as a liver cancer is generally elliptical or circular, a relatively accurate outline can be easily drawn by using a variable elliptical figure. Of course, the contour may be drawn by tracing the outline with a moving cursor (cursor) or the like.

The operator causes the image processor 148 to store the drawn outline figure. The operator further inputs the numbers of the sections 900, 906, and 910, and causes the image processor 148 to store the positions of the sections in the three-dimensional area 302. The image processor 14
If the three-dimensional position of the currently displayed cross section is always recognized, the user can store the three-dimensional position by pressing a predetermined key instead of inputting the number.

The image processor 148 determines the three-dimensional shape of the tumor 922 based on these input signals.
For this purpose, for example, a method as shown in FIG. 10 is used. As shown in the figure, the outline of the thickest intermediate portion in the section 906 is represented by an ellipse having a major axis a and a minor axis b.
6 to sections 900 and 910, respectively,
And L, the contour of the tumor 922 at the distance i between the cross section 906 and the cross section 900 is defined by the major axis a ′ and the minor axis b ′.
Are ellipses given by the following equations (1) and (2), respectively, and the contour at a distance i between the cross-section 906 and the cross-section 910 is defined as follows.
Let it be an ellipse given by equation (4). Note that the case where a = b is included.

[0041]

(Equation 1)

[0042]

(Equation 2)

[0043]

(Equation 3)

[0044]

(Equation 4)

As a result, the three-dimensional shape of the tumor 922 is obtained as a smooth approximate figure formed by laminating a plurality of elliptical plates (elliptical laminates). That is, in the three-dimensional region 302, the region of interest 922 'corresponding to the tumor 922 is set three-dimensionally.

Next, the image processor 148 rewrites all the image data in the image memory 146 belonging to the region of interest 922 'to the minimum value. For example, 0 is selected as the minimum value. By minimizing the image data of the region of interest 922 'in this manner, it becomes possible to obtain a three-dimensional display image of the region of interest 922' together with blood vessels, as described below.

After rewriting the image data in the region of interest 922 'to 0, the image processor 148 forms a three-dimensional display image from the image data in the three-dimensional coordinate space. 3
The formation of the two-dimensional display image is performed by using a minimum intensity projection (MIP) technique. That is, the image processor 148
Represents the three-dimensional area 30 stored in the image memory 146.
The MIP processing is performed on the image data related to No. 2.

The MIP process is, as is well known,
In the desired projection direction set for the three-dimensional area 302,
With a number of lines of sight along the projection direction, the three-dimensional area 302
Is the process of projecting the minimum value of the image data in.

Since the echo from the blood is much weaker than the echo from the tissue, a projected image of the blood vessel 920 is obtained by the MIP processing. In addition, a projection image of the region of interest 922 ′ with the image data set to 0 is also obtained. Since the region of interest 922 'is approximated to the three-dimensional shape of the tumor, a three-dimensional display image in which the blood vessel image and the tumor image are drawn together is obtained.

FIG. 1 shows an example of a displayed image by using a halftone photograph.
It is shown in FIG. In the figure, two black strips obliquely descending from the right are blood vessel images, and an ellipse blackened out above is a tumor image. M with slightly changed projection direction
By displaying the IP images continuously, the mutual relationship between the two images can be easily grasped three-dimensionally.

[0051]

As described above in detail, according to the present invention, the image data in the three-dimensional region of interest in the three-dimensional coordinate space where the B-mode image data exists is minimized, and the image data is minimized. Since the minimum value projection is performed on the B-mode image data in the three-dimensional coordinate space including the region of interest, and an image is formed based on the image data on which the minimum value is projected, the image of the three-dimensional region of interest is added to the image of the blood vessel. Is projected to the minimum value. Therefore, by setting the range of the tumor part observed on the B-mode image as a three-dimensional region of interest, a three-dimensional display image displaying the blood vessel image and the tumor part image together can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of a device according to an example of an embodiment of the present invention.

FIG. 2 is a conceptual diagram of sound ray scanning performed by the apparatus according to the embodiment of the present invention;

FIG. 3 is a conceptual diagram of three-dimensional scanning performed by an apparatus according to an embodiment of the present invention;

FIG. 4 is a conceptual diagram of three-dimensional scanning performed by the apparatus according to an embodiment of the present invention;

FIG. 5 is a block diagram of a part of an apparatus according to an embodiment of the present invention;

FIG. 6 is a block diagram of a part of the device according to an example of the embodiment of the present invention;

FIG. 7 is a conceptual diagram showing a sound ray data space in an apparatus according to an embodiment of the present invention.

FIG. 8 is a conceptual diagram showing a physical space in an apparatus according to an embodiment of the present invention.

FIG. 9 is a conceptual diagram showing an operation of the device according to an example of the embodiment of the present invention.

FIG. 10 illustrates an example of an apparatus according to an embodiment of the present invention.
It is a conceptual diagram of a dimensional region of interest.

FIG. 11 is a diagram showing an example of a screen displayed on a display unit of the apparatus according to the embodiment of the present invention, as a halftone photograph.

[Explanation of symbols]

 2 Ultrasonic probe 4 Subject 6 Transmission / reception unit 8 Actuator 10 B-mode processing unit 14 Image processing unit 16 Display unit 18 Control unit 20 Operation unit 102 Logarithmic amplifier circuit 104 Envelope detection circuit 140 Bus 142 Sound ray data memory 144 Digital scan Converter 146 Image memory 148 Image processor 200 Radiation point 202 Sound ray 204 Arc 206 Two-dimensional area 208 Divergence point 300 Rotation axis 302 Three-dimensional area 900-910 Cross section 920 Vessel 922 Tumor 922 'Region of interest 924 One end 926 Middle part 928 Other edge

Claims (2)

[Claims] 1. A three-dimensional coordinate space including a three-dimensional region of interest in which a three-dimensional region of interest in a three-dimensional coordinate space in which B-mode image data exists is minimized. A minimum value projection for the B mode image data, and forming an image based on the minimum value projected image data. 2. An ultrasonic transmission / reception means for scanning a three-dimensional region in an object with ultrasonic waves and receiving an echo thereof, and a B-mode image representing a B-mode image in the object based on an intensity signal of the echo. B-mode image data generating means for generating data; minimizing means for minimizing image data in a three-dimensional region of interest in a three-dimensional coordinate space in which the B-mode image data exists; Minimum value projection means for performing minimum value projection on the B-mode image data in the three-dimensional coordinate space including the three-dimensional region of interest, and an image forming an image based on the image data obtained by the minimum value projection means An ultrasonic imaging apparatus comprising: a forming unit.