JP2556310B2 - Ultrasonic diagnostic equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ultrasonic imaging apparatus configured to obtain an echo image of a target by transmitting and receiving ultrasonic waves, and particularly suitable for medical diagnosis. The present invention relates to an ultrasonic diagnostic apparatus that gives spatial distribution information of organ motion velocity.

[Prior art]

In ultrasonic diagnosis, the two-dimensional distribution of blood flow velocity is detected,
As an apparatus for displaying the image by color tone, an example described in the collection of lectures by the Japanese Society of Ultrasonics in Medicine (42-C-61, 1983),
There was an example described in JP-A-60-99237. Describes a system for collecting and displaying a two-dimensional distribution of blood flow information in real time in B mode and M mode. Is captured as an image with echoes of particles contained in the flow of the liquid in the subject, and the temporal change of the image is used to detect the amount of movement of each point in the image and its direction by the correlation method, and the two-dimensional blood flow is detected. A device for measuring distribution in real time is described, and the digital scan converter used in this device also has a function of extracting echo image information of particles contained in the flow of a liquid in a subject. Further, in the apparatus described in (1), the digital scan converter has high sensitivity so as to effectively obtain an echo image of red blood cells, and a tomographic image of a tissue with a large echo amplitude is saturated, and an echo image of red blood cells is saturated. Appears prominently. Since these conventional devices are designed for the purpose of measuring blood flow velocity, they are not suitable for detecting a relatively small motion velocity such as the motion velocity of internal organs.

[Problems to be solved by the invention]

Movement speeds such as translational movements and deformation movements of internal organs also provide useful ultrasonic diagnostic information in a sense different from the blood flow velocity. For example, when there is a tumor in an organ, the movement of the tumor part associated with breathing, pulsation, etc. is different from the surroundings. Therefore, it is possible to detect and diagnose a tumor by detecting the moving speed and displaying the image, and it has been desired to develop such a device.

An object of the present invention is to provide an ultrasonic diagnostic apparatus which detects the moving speed of internal organs and displays it as an image, which is useful for medical diagnosis as described above.

[Means and Actions for Solving Problems]

According to the above object, in the present invention, in an ultrasonic diagnostic apparatus configured to obtain an echo signal of a target by transmitting and receiving ultrasonic waves, a storage unit for storing a received signal and an inspection based on the stored received signal A diagnostic device is proposed in which means for detecting the motion velocity of each part in the target and means for displaying an echo image of each part in the color tone according to the detected motion speed are added.

An ultrasonic diagnostic apparatus of the present invention has a unit for generating an ultrasonic beam, scans an ultrasonic beam two-dimensionally on an inspection target, and receives a reflected signal from the inspection target. Store the received signal with the signal held 2
A two-dimensional velocity vector representing the motion velocity of each part in the inspection target by calculating the two-dimensional cross-correlation function between the two-dimensional storage means and the received signals stored in the two-dimensional storage means with a fixed time difference. Is characterized by having a motion velocity detecting means for detecting.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a block diagram of the system configuration of an embodiment of the present invention. A pulse ultrasonic wave is transmitted and received through the array type electronic scan probe 1 by the transmission / reception circuit 2 controlled by the scan control circuit 3. The reception signal reflected by the subject and received by the probe 1 and obtained by the transmission / reception circuit 2 receives a corresponding address (time difference from transmission to reception and pulse) in the two-dimensional memory 4 or 5 according to an instruction from the scan control circuit 3. The coordinates corresponding to the scanning direction of the circular ultrasonic beam (the coordinates are given by the coordinate system (x, y) based on the array type electronic scanning probe 1) are written. The above is the conventional B
The configuration may be the same as that of the mode ultrasonic imaging apparatus, but in order to realize high resolution in detecting the motion in the ultrasonic beam direction, the envelope signal is not written in the memory as in the conventional B mode apparatus, but a carrier wave is used. The received signal as it is is written in the memory (here, the carrier wave means an AC signal surrounded by the envelope of the received signal obtained by the transmitting / receiving circuit 2). That is, the reflected signal from the object received by the probe is written in the memory without being converted into an envelope signal as in the conventional B-mode device.

The addresses corresponding to the memories 4 and 5 are
A reflection signal from the same position having the constant time difference (ΔT) (the same position in the coordinate system (x, y) with the array type electronic scan probe 1 as a reference) is written. The reflection point within the subject moves, for example, in the direction of the arrow in the direction of the arrow by the length of the arrow during this constant time difference (ΔT) (from the position of the circle at the lower left to the circle at the upper right). Move to the mark position). The signal data read from each of the memories 4 and 5 is the position (X, Y) at which the motion velocity is measured (position in the coordinate system with the array type electronic scan probe 1 as a reference).
Velocity control position control circuit 6 for controlling (designating)
Is processed by the window processing circuits 7 and 8 and written in the two-dimensional memories 9 and 10. This window processing is performed, for example, in "Trikeps Technical Reference No. 56, Digital Image Processing Technology".
Figure 1 on page 90 of (Publisher: Trikeps) (1981)
-1, refers to processing a portion of the input image (data) (eg, only within the specified rectangle). The contents of the window processing by the window processing circuits 7 and 8 are stored in the two-dimensional memories 4 and 5,
Origin (X = 0, Y = 0) at the position (X, Y) for measuring motion velocity
Is to read out the signal data of an address within a predetermined range and write it in the two-dimensional memories 9 and 10 in order to obtain the cross-correlation described below.

The cross-correlation between the data in the two-dimensional memories 9 and 10 is calculated by the cross-correlation calculation circuit 11 to obtain the motion velocity vector. The cross-correlation is similar to that described in JP-A-60-99237, and the data of the two-dimensional memory 9 is f (x, y) with the memory address as (x, y).
y), the data of the two-dimensional memory ₁₀ f ΔT _(x, when a y), f (x, y ) and _f ΔT _(x, y) and the cross-correlation C _{f of, FderutaT}
Is defined by equation (1).

C _{f, f ΔT} (ξ, η) = ∫ _X ∫ _Y f (x, y) f _ΔT (x +
ξ, y + η) dxdy / ∫ _X ∫ _Y {f _ΔT (x + ξ, y + η)} ² dxdy
(1) The integrals ∫ _X and ∫ _Y regarding x and y in the equation (1) are discretized as in the equation (2) in the actual calculation and are performed by addition Σ _X and Σ _Y regarding x and y.

C _{f, f ΔT} (ξ, η) = Σ _X Σ _Y f (x, y) f _ΔT (x +
ξ, y + η) / Σ _X Σ _Y {f _ΔT (x + ξ, y + η)} ² ...
(2) In the equation (2), the addresses of the data of the two-dimensional memories 9 and 10 are relatively shifted by (ξ, η), and the product sum of the data of the corresponding addresses at that time is taken and standardized. Means that.

The cross-correlation function C thus obtained
Position that gives the maximum of _{f, fΔT} (ξ, η) (peak position)
Letting (ξ, η) be (X _P , Y _P ), the data point (origin) f (x = 0, y = 0) of the two-dimensional memory 9 has a constant time difference (Δ
T), the distance (eg, the length of the arrow at the top of FIG. 1) Data points f _ΔT of the two-dimensional memory 10
You can see that it moved to (X _P , Y _P ). That is, when the coordinates of the peak position of the cross-correlation function C _{f, f ΔT} (ξ, η) are set as (X _P , Y _P ), the coordinate system (x, y) with the array-type electronic scanning probe 1 as a reference is set. In, the (x component, y component) of the motion velocity vector to be obtained is given by (X _P / ΔT, Y _P / ΔT). By changing the position (X, Y) at which the motion velocity is measured, the cross-correlation function C _{f, fΔT} (ξ,
By performing the calculation for obtaining η), the motion velocity of each part of the subject can be detected as a two-dimensional vector.

Calculation of the component of the direction of interest of the motion velocity vector, and the determination of the color tone according to the size thereof is performed by the display color calculation circuit 13 according to the signal from the direction-of-interest designation control circuit 12 for designating the direction of attention, Data representing the determined color tone is written in the address of the two-dimensional memory 14 corresponding to the position where the exercise velocity is measured. At the time of data transfer to the display device, the data in the two-dimensional memory 4 or 5 and the data in the two-dimensional memory 14 at the corresponding address are transferred as luminance modulation data and color modulation data, respectively. As a method of associating the motion speed with the color tone, for example, there is a method in which the positive maximum speed is displayed in red, the negative maximum speed is displayed in purple, and the intermediate speed is associated in the order of the light spectrum.

In the above description, an example in which the array type electronic scanning probe is used to detect the motion velocity as a two-dimensional vector and display the two-dimensional distribution thereof is described. If a system capable of three-dimensional scanning is used to detect motion velocity as a three-dimensional vector and display a three-dimensional distribution,
Alternatively, it is also applied to the case where only the component of the motion velocity in the ultrasonic beam direction is detected and the two-dimensional distribution thereof is displayed, or when the mechanical scanning probe is used.

In a usual medical ultrasonic diagnostic apparatus, the echo signal from the reflector is detected and converted into an envelope signal, but as described above, in the present invention, the carrier wave is kept as it is without detection. The received signal is stored in the memory and is used to detect the motion velocity vector. Therefore, the detection sensitivity of the component of the motion velocity in the ultrasonic beam direction (depth direction) is determined by using the conventional envelope signal. Several times better than. This improvement in the detection sensitivity can be realized by avoiding the deterioration of the resolution due to the process of obtaining the envelope signal (the width of the envelope signal of the echo signal by the reflector is several times the wavelength of the carrier).

〔The invention's effect〕

As described above, according to the present invention, it is possible to detect a relatively small motion velocity such as translational motion and deformation motion of internal organs with a high speed resolution of several times that of the related art, and a diagnosis useful for tumor discovery, diagnosis, etc. The ultrasonic diagnostic equipment that gives information is
This can be realized by a relatively small increase in cost for the mode ultrasonic imaging apparatus, and the medical or industrial effect of the present invention is extremely large.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. [Explanation of Codes] 1 ... Array-shaped electronic scanning probe, 2 ... Transmission / reception circuit, 3 ... Scan control circuit, 4, 5 ... Two-dimensional memory, 6 ... Movement speed measurement position control circuit, 7, 8 ... Window processing circuit, 9, 10 ... Two-dimensional memory, 11 ... Cross-correlation calculation circuit, 12 ... Target movement direction designation control circuit, 13 ...
… Display color tone calculation circuit, 14 …… two-dimensional memory.

Front page continuation (72) Inventor Toshio Ogawa 1-280 Higashi Koigakubo, Kokubunji, Tokyo Inside Central Research Laboratory, Hitachi, Ltd. (72) Inventor Shinichi Kondo 1-280 Higashi Koigakubo, Kokubunji, Tokyo Inside Central Research Laboratory, Hitachi Ltd. (72) Inventor Hiroshi Ikeda 1-280, Higashi Koigakubo, Kokubunji, Tokyo (56) References JP-A-60-99237 (JP, A) JP-A-59-77841 (JP, A) JP-A-57-11640 (JP, A)

Claims (1)

(57) [Claims] 1. An ultrasonic diagnostic apparatus having means for generating an ultrasonic beam, which scans an ultrasonic beam on an inspection object two-dimensionally and receives a reflected signal from the inspection object, having a carrier wave. The two-dimensional storage means for storing the received signal as it is and the two-dimensional cross-correlation function between the received signals received at a fixed time difference stored in the two-dimensional storage means for calculating An ultrasonic diagnostic apparatus comprising: a motion velocity detecting means for detecting a two-dimensional velocity vector representing a motion velocity of each part.