JPH04150843A - Ultrasonic diagnosing apparatus - Google Patents

Abstract

PURPOSE:To enable identification of a direction of motion of a moving part by a change in color without use of a contrast medium by arranging a means to judge a direction of movement of a moving part, a means to add a color code corresponding to the direction of movement and a means which impart a hue specified by the color code to a differential image data for a color display. CONSTITUTION:An differential image is displayed in blue. Moreover, an adder 12 connected to the output side of a color mapping circuit 11 serves as a means which adds up a differential image data color coded with the color mapping circuit 11 and an original image data before an arithmetic processing as outputted from a DSC5 to perform a display with an image display device 7 simultaneously. Then, frame memories 10a-10n, the color mapping circuit 11 and the adder 12 are combined to accomplish a conversion into a color as specified by a color code added with a data collection circuit 8 for judging a direction of movement to display a differential image. This enables identification of a direction of motion of a moving part of an object to be inspected by a change in color.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an ultrasonic diagnostic apparatus that uses ultrasound to obtain a tomographic image of a diagnostic region of a subject, and in particular, the present invention relates to an ultrasonic diagnostic apparatus that uses ultrasound to obtain a tomographic image of a diagnostic region of a subject. The present invention relates to an ultrasonic diagnostic apparatus that is capable of depicting the movement of moving parts such as the heart, blood vessels, and blood flow, and is capable of identifying the direction of movement of the moving parts by changes in color.

[Conventional technology]

B-mode display is a method of displaying images of the blood flow, heart, etc. inside the subject in real time using ultrasound.

Doppler mode display, etc. are known, but the latest method is an attempt to obtain a differential image by calculating between ultrasound tomograms, as reported in British Heart Journal 59 (1988).
) pages 12 to 19 (British Hear
tJournol 59 (1988) PP12-19
) is discussed.

This method uses a contrast agent to perform subtraction between tomographic images before and after the contrast agent is injected, so that, for example, a region of interest in the heart can be observed with contrast.

That is, in this image display method, as shown in FIG. 5, first, before injecting the contrast agent into the subject, for example, four frames of ultrasonic tomographic images are captured, and these four frames of images are averaged. A mask image is created, and then a contrast medium is injected into the subject, and tomographic images are acquired over time from the time when the contrast medium reaches the diagnosis site, and the mask image and each tomographic image after the contrast medium injection are combined. A method is adopted in which subtraction is performed in between to sequentially obtain difference images. Note that in this method, the density of each pixel in the image serving as the mask image is the average value of the density of corresponding pixels in four frames. The reason for this is to reduce the influence of random noise on the difference image and obtain a better difference image.

In addition, as an ultrasonic diagnostic device that displays such differential images, the 55th Japanese Society of Ultrasound in Medicine Proceedings (198
Pages 291 to 292 of the 56th Japanese Society of Ultrasonics in Medicine (published on October 4, 1990), pages 291 to 292 of
Published in May), pages 351 to 354. The display of difference images in these ultrasonic diagnostic apparatuses involves performing a difference between time-series tomographic images and sequentially displaying the obtained difference images one by one.

[Problem to be solved by the invention]

However, in the former case, when displaying images using conventional ultrasonic diagnostic equipment, a contrast agent is injected into the blood of the subject and the places where blood moves, such as the ventricles and atria, are visualized with enhanced contrast. Therefore, it has been difficult to obtain movement information of areas with low blood flow, for example, the tissue itself. Furthermore, although the movement status of the inner walls of the ventricles and atria can be grasped, the movement status of the outer walls cannot be observed. Furthermore, in order to inject a contrast agent into the subject,
It could not be applied to people who could not tolerate it.

In addition, in the latter case, real-time differential image display is possible without using a contrast agent, and conventional tomographic image display can display Il! It has been reported that premature ventricular contractions, which had previously been impossible to detect, can be displayed as images. Since it is only displayed, the state of movement of moving parts such as organs has to be determined by relying on the afterimage effect of human vision.

That is, in the above conventional example, for the direction of movement of the moving part of the subject, the change in the displayed difference image is expressed as m.
It requires a lot of attention, and it requires a lot of attention and judgment based on the visual afterimage effect. Individual differences among examiners arise, making diagnosis difficult.

Therefore, the present invention solves these problems and makes it possible to visualize the movement of moving parts such as the heart and blood vessels within the subject without using a contrast agent, and to change the color to indicate the direction of movement of the moving parts. The purpose of the present invention is to provide an ultrasonic diagnostic device that can be identified by

[Means to solve the problem]

In order to achieve the above object, an ultrasonic diagnostic apparatus according to the present invention includes an ultrasonic transmitting/receiving means for transmitting and receiving ultrasonic waves to and from a subject, and a moving part using a reflected echo signal from the ultrasonic transmitting/receiving means. a tomographic scanning unit that repeatedly obtains tomographic data within a subject at a predetermined period; a unit that performs calculations between time-series images obtained by the tomographic scanning unit to generate differential image data; and the tomographic image. In an ultrasonic diagnostic apparatus having an image display device that displays data and differential image data from the differential image data generation means, the direction of movement of the moving region is detected in the tomographic image displayed on the display screen of the image display device. means for displaying a mark specifying detection; means for determining the moving direction of the moving part using differential image data corresponding to the position of the displayed mark; means for adding a color code according to the direction of movement of the moving part;
The apparatus further includes means for displaying the difference image in color by adding a hue specified by the color code added by the color code adding means to the difference image data.

[For production]

The ultrasonic diagnostic apparatus configured in this manner displays a mark specifying the detection of the moving direction of the moving region in the tomographic image displayed on the display screen of the image display device by the mark display means, and uses the moving direction determining means to The movement direction of the moving part is determined using the difference image data corresponding to the position of the mark displayed by the mark display means, and the color code addition means moves the movement part according to the difference image data according to the output from the movement direction determination means. A color code corresponding to the direction of movement of the part is added, and the image display means adds a hue specified by the color code added by the color code adding means to the difference image data, so that the difference image is displayed in color. Operate. Due to this.

The direction of movement of the moving part of the subject can be identified by a change in color.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of an ultrasonic diagnostic apparatus according to the present invention. This ultrasonic diagnostic apparatus uses ultrasonic waves to obtain a tomographic image of a diagnostic part of a subject.
, a video signal processing circuit 4, a digital scan converter (hereinafter abbreviated as rDSCJ) 5, a subtracter 6, and an image display device 7, and further includes a moving direction detection mark setting device 30 and a moving direction determining device. , a color code adding circuit 9 , image memories 10 a to Ion, a color mapping circuit 11 , an adder 12 , and a controller 18 .

The probe 1 performs beam scanning mechanically or electronically to transmit and receive ultrasonic waves to the subject. Although not shown, there is a part of the probe that is the source of the ultrasonic waves as well as the reflected echo. It has a built-in transducer to receive it. The transmitting circuit 2 generates a transmitting pulse for driving the probe 1 to generate an ultrasonic wave, and also sets the convergence point of the transmitted ultrasonic wave to a certain depth using a built-in transmitting phasing circuit. It is set to . Further, the receiving circuit 3 amplifies the reflected echo signal received by the probe 1 with a predetermined gain, and controls the phase to one or more convergence points using a built-in receiving phasing circuit to beam the ultrasound beam. It forms the Furthermore, the video signal processing circuit 4 receives the received signal from the receiving circuit 3 and performs signal processing such as gain correction, log compression, edge enhancement, and filter processing. The probe 1, the wave transmitting circuit 2, the receiving circuit 3, and the video signal processing circuit 4 collectively constitute an ultrasound transmitting/receiving means, and the probe 1 transmits the ultrasound beam to the subject. A single tomographic image is obtained by scanning in a certain direction inside the body.

The DSC 5 uses the reflected echo signal output from the video signal processing circuit 4 of the ultrasound transmitting/receiving means to obtain tomographic image data within the subject including moving tissues at the ultrasound transmission period, and displays this data. It is a means for reading out data in synchronization with the TV and a means for controlling the system.
A/D converter 13 that converts the reflected echo signal from the video signal processing circuit 4 into a digital signal;
A plurality of frame memories 14a store tomographic image data digitized by the converter 13 in time series.

14b,... 14n and these frame memories 1
an ultrasonic wave transmission synchronization circuit 15 that generates a write timing when writing tomographic image data in the frame memories 14a to 14n; and a television synchronization circuit 1 that generates a read timing when reading tomographic image data from the frame memories 14a to 14n.
6, and a controller 17 that controls the operations of these components.

The subtracter 6 is a means for performing calculations between the time-series tomographic images obtained by the DSC 5 to generate differential image data, and is read out at the readout timing from the television synchronization circuit 16. It is designed to perform subtraction between two pieces of tomographic image data, and is configured using standard logic. The one-image display device 7 displays the difference image data output from the subtracter 6 as an image, and includes, for example, a D/A converter that converts the difference image data into an analog signal, and a D/A converter that converts the difference image data into an analog signal. It consists of a television monitor that inputs video signals and displays them in color.

In this embodiment, as shown in FIG. 1, a moving direction detection mark setter 30 is connected to the controller 17, and a moving direction determination data collection port J18 is provided on the output side of the subtracter 6. In addition, a color code addition circuit 9 is provided, and frame memories 10a to 10n, a color mapping circuit 11, and an adder 12 are connected to the output side of the color code addition circuit 9, and a controller 18 for these is connected. It is provided. The moving direction detection mark setting device 30 is configured to arbitrarily set the detection of the direction in which the inspection target region moves over time.
For example, the controller 1 is
7 to one of the frame memories 14a to 14n or a dedicated graphics memory (not shown).
For example, an arrow 31 (mark) of arbitrary length having a starting point and an ending point as shown in FIG.
The pixel address group of the tomographic image data in the frame memories 14a to 14n corresponding to this arrow is set.

The moving direction determination data collection circuit 8 includes a frame memory 1
A pair of tomographic image data to be read out of 4a to 14n is differential image data outputted via the subtracter 6, and is from a starting point corresponding to the arrow 31 specified by the movement direction detection mark setting device 30. It collects differential data towards the end point.

The color hood addition circuit 9 adds a color code to the difference image data for coloring according to the direction of movement of the region to be inspected, based on the determination result of the movement direction, and adds a flag bit for the color code to the difference image data. 1-bit data is added as . More specifically, when we take the difference between the two tomographic images, the difference data is "positive J" and "zero".

It is classified into three levels of "negative", but at the "zero" level, the object is stationary and cannot be used to determine the direction of movement; however, when displaying moving parts as in the present invention, The movement direction can be determined by detecting that the part corresponding to a certain part on the difference image changes from "positive" to "negative" or from "negative" to "positive", that is, from which direction the zero cross was made. can be determined. Therefore, for example, if the difference image data on the arrow shown in FIG. Furthermore, when the value changes from "positive" to "negative", "1" is assigned to the flag bit.

The moving direction determination data collection circuit 8 sends the data at the address on the arrow out of the output of the subtracter 6 to the controller 18 in order to identify the pattern of this change. The controller 18 recognizes the pattern based on the input data, outputs the corresponding flag bit data "0" or "1" to the color code addition circuit 9, and the color hood addition circuit 9 outputs "O' or 1" to the differential image data. Write the data for the color code.

Multiple frame memories 10a, 10b,... 10n
stores the difference image data generated by the calculation of the subtracter 6 from a plurality of tomographic image data corresponding to, for example, one cycle of the moving tissue of the subject, and the controller 18 described later stores each image data. Only writing and reading are controlled. Further, the color mapping circuit 11 connected to the output side of this frame memory 10a = 10n is connected to each frame memory 10a = 10n.
When reading the differential image data from ~10n in synchronization with the readout clock of the television synchronization circuit 16, the required coloring is performed according to the value of the 1-bit color code flag added by the color code addition circuit 9. 3 compatible with R, G, and B signals of color TV monitors
The differential image data to which the color code has been added is input to the address of each ROM. For example, when the value of the color code flag is "0", the color is colored red, and when the value of the color code flag is "1", the color is colored blue. And with this coloring,
For example, the difference image will be displayed in red when the blood vessel serving as the diagnostic site of the subject is in dilation motion, and in blue when it is in contraction motion. Furthermore, this color mapping circuit 11
An adder 12 connected to the output side of the color mapping circuit 11 and the DSC
This is a means for adding the original image data outputted from 5 and before the above-mentioned arithmetic processing and displaying the resultant data on the image display device 7 at the same time. and.

These frame memories 10a to 10n, the color mapping circuit 11, and the adder 12 provide means for displaying a difference image by converting it into a color specified by the color code added by the moving direction determination data collection circuit 8. It consists of

The controller 18 also includes the moving direction determination data collection circuit 8, a color code addition circuit 9, frame memories 10a to Ion, and a color mapping circuit 11.
It controls each operation in the adder 12.

Next, the operation of the ultrasonic diagnostic apparatus of the present invention configured as described above will be explained. First, the probe 1 shown in FIG. 1 is brought into contact with a position corresponding to a diagnostic site of a subject, and ultrasonic waves are transmitted to the diagnostic site. At this time, the ultrasonic waves transmitted from the probe 1 are made to form a narrow beam at the diagnosis site by a transmission phasing circuit in the wave transmission port j12. This transmitted beam hits the diagnostic site and reflects the reflected echo, which is received by the probe 1 and received by the receiving circuit 3.
A receiving beam is formed by a delivery phasing circuit inside the receiver.

Then, the ultrasound transmission and reception directions from the probe 1 are repeated at predetermined intervals by sequentially changing the ultrasound transmission and reception directions, thereby scanning the diagnostic region.

The receiving beam output from the receiving circuit 3 is as follows.

After undergoing necessary signal processing in the video signal processing circuit 4, it is sent to the DSC 5 as a reflected echo signal, and then input to the A/D converter 13 where it is converted into a digital signal. This DS
The C5 has a plurality of line memories (not shown), and each time the ultrasonic wave transmission/reception direction changes, writing and reading are performed by switching under the control of the controller 17. The reflected echo signals are sent to frame memories 14a-14n. The reflected echo signals input to the frame memory 14 a = 14 n are stored in the frame memory 14 a as a first image storage area by a control signal from the controller 17 so that their transmission and reception directions are made to correspond to each other for each ultrasonic beam. The first image is written as one tomographic image.

When the ultrasonic scanning for one tomographic image is completed in this way, the probe 1 returns the wave transmission and reception direction to the initial direction again under the control of the wave transmitting circuit 2 and the receiving circuit 3, and starts transmitting and receiving ultrasonic waves. As it repeats, the wave transmission/reception direction is updated and scanning is performed.The reflected echo signal collected this time is also A/D converted in the same way as above, and is stored in the frame memory 14 in the DSC 5.
Sent to a to 14n. The reflected echo signals captured in the current scan are stored in the frame memory 14b as a second image storage area under the control of the controller 17.
is written as one tomographic image to form a second image. At this time, frame memories 14a, 14b,...
The tomographic image data is sequentially taken in, read out in synchronization with the synchronizing signal of the television synchronization circuit 16, and displayed as a tomographic image on the image display device 7. Operations of 0 or more are normal ultrasound diagnosis. This is the same as the tomographic image display operation in the device.

Next, the operation of differential image display will be explained.

First, the operator observes the tomographic image on the display screen of the image display device 7, and writes the arrow 31 shown in FIG. outputs the addresses on the frame memories 14a to 14n corresponding to this arrow 31 to the controller 18 in the order from the start point to the end point of the arrow 31. Here, when the operator commands to start displaying the difference image from an operating device (not shown), the controller 17 sends a command to the frame memory 14a.
and 14b, the first image and the second image of the tomographic image are read out in pixel correspondence in synchronization with the television.The read out first image and second image are sequentially subtracted lI68, and
Image operations are performed. The difference image data that is the calculation result is input to the data collection circuit 8 for determining the moving direction.

At this time, the controller 18 sends a command to the moving direction determination data collection circuit 8 to output the differential image data only for the addresses on the arrow to the controller 18. Therefore, the moving direction determination data collection circuit 8 inputs to the controller 18 only the differential image data corresponding to the arrow designated by the moving direction detection mark setter 30 out of the sequentially inputted differential image data. Then, the controller 18 sequentially arranges the input data from the start point to the end point of the arrow 31 into an array pattern of rjIEJ and "negative J."

The controller 18 has a built-in memory that stores a predetermined pattern, for example, a pattern in which data changes from "negative" to "positive", and compares this stored pattern with the pattern of input data. , when the patterns match, "O" is output to the color code addition circuit 9, and when they do not match, "1" is output to the color code addition circuit 9.

The differential image data between the first image and the second image is sequentially written to 10a of the frame memories 10a to 1on, but a color code addition circuit 9 adds 1 bit for a flag for color code addition. Frame memory 1
Written to 0a.

When the differential image data for one frame has all been written to the frame memory loa, the color code adding circuit 9 sets all the color code flag bits to the same "O" or "
Write 1”.

The tomographic data is read out sequentially from the second image and the third image.
image, then the third image, the fourth image,...th (n −1
) image and the n-th image in sequence, and their difference image data is processed in the same way as above.

The data is written to the frame memories 10b to Ion.

At the time when predetermined difference data and color codes are written into the frame memories 10a to Ion, reading height of the difference image data from the frame memory 10a is started. This reading is performed in synchronization with the synchronizing signal from the television synchronizing circuit 16, and the read differential image data is output to the color mapping circuit 11.

The color mapping circuit 11 performs required coloring on the input difference image data according to the value of the color code flag bit. For example, if the color code flag is “0”
”, it is colored red, and when it is “1”, it is colored blue.Then, this colored difference image data is output to the adder 12, and the tomographic image from which the difference image data was generated is It is added to one of the data and displayed on the display screen of the image display device 7. Note that the image display may be such that only the difference image is displayed as desired.

Next, the coloring and display of the difference image will be explained in more detail. FIG. 2 shows the relationship between the tomographic image and the difference image. FIGS. 2(a), (b), and (c) are tomographic images of a blood vessel, such as a carotid artery, and FIG. 2(a) is a tomographic image at a certain time T, which is read from the frame memory 14a. (b) shows the data from the frame memory 14b, and (b) shows the data from the frame memory 14b.
It is assumed that (C) corresponds to a display of data from frame memo +J 14 c. From Figure 2(a) (
The process leading to b) corresponds to a cycle in which blood vessels expand in response to the contraction of the heart and a large amount of blood flows, and from (b) to (c)
The process leading to this corresponds to the period in which the heart valves close and the blood vessels constrict.

As shown in FIG. 3, the operator operates the moving direction detection mark setting device 3o to write an arrow 31 on the tomographic image of an arbitrary time phase on the display screen of the image display device 7. arrow 31
The starting point address of is (xat yo
), the end point address corresponds to (Xi, Y,) from the graphic memory, and the address on the line between the start point and end point is calculated by the CPU in the controller 17.

From this starting point (X (+, Yll) to the ending point (X,, Y)
Each address data between is output to the controller 18.

The controller 18 has a built-in memory, and a pattern that changes from the starting point to the ending point, for example, from "negative" to "positive", is recorded in this memory (see FIG. 4), that is,
The memory stores zero cross pattern recognition data. Then, the controller 18 outputs the input address data to the moving direction determination data collection circuit 8. The above is the preparation operation for displaying the difference image.

Next, a differential image display operation begins. Frame memory 14
A pair of tomographic image data from a to 14n is read out as a pair, for example as shown in FIGS. 2(a) and 2(b), and is input to the subtracter 6. Subtraction is then performed for each corresponding address, and the resulting difference image data is output to the moving direction determination data collection circuit 8. The difference image between the first image shown in FIG. 2(a) and the second image shown in FIG. 2(b) is as shown in FIG. 2(d). In addition, Fig. 2(d)
The black-filled area 19 indicates negative data, and the white-edged area 19' indicates positive data.

The data collection circuit 8 for determining the moving direction is connected to the controller 18
According to the command, the data indicated by the broken line in FIG. 2(d) are sequentially fetched and output to the controller 18. Then, the controller 18 compares and determines the zero cross pattern of this input data. In the case of Figure 2(d),
It is determined that the pattern is the same as the pattern shown in FIG. Based on this determination result, the controller 18 outputs '0' to the color code addition circuit 9.

A color code addition circuit 9 adds one bit for a color code flag to the differential image data.

The data are sequentially written into the frame memory 10a. When one frame of difference image is written to the frame memory 10a,
The color code addition circuit 9 writes "0" to the color code flag bit of each data in the frame memory 10a.The timing of this writing is the timing of starting reading of primary tomographic image data or the initial setting of ultrasound scanning. timing etc. can be used.

Next, from the frame memories 14b and 14c, as shown in FIG.
The tomographic image data of and (c) are similarly read out. In this case, the difference image output from the subtracter 6, that is, the second
The difference image between the image and the third image is as shown in FIG. 2(e). At this time, the zero cross pattern of the data output from the moving direction determination data collection circuit 8 is opposite to that shown in FIG. 4. Therefore.

The controller 18 inputs “1” to the color code addition circuit 9.
Output to. In other words, in this case, it is detected that the inspection target region is moving in the opposite direction when the first and second images were captured. Then, the color code adding circuit 9 writes "1" to the color code flag bit of the second difference image data written in the frame memory 10b.

The difference image data to which the color code has been added in this way is colored by the color mapping circuit 11 as described above, is output to the adder 12, and is added to the tomographic image data and displayed sequentially. In addition.

As mentioned above, the coloring in the color mapping circuit 11 is preferably performed so that the hues are obviously significantly different, such as red when the color code flag is "0" and blue when it is '1'. Also, should "positive" and "negative" data in the difference image be displayed with a difference in brightness level of the same hue?

A hue may be assigned only to "positive" data, and "black" may be assigned to "negative" data.

The gist of the present invention is to automatically determine the moving direction of the inspection target region using differential image data, and to color and display the differential image based on the determination result. For example, the moving direction of the region to be inspected can be determined by using a desired line difference data such as the arrow 31 in the above embodiment that can set the starting point and ending point. A pattern recognition method using differential data within a rectangle or circle having an area can also be used.

Furthermore, although the above embodiments have been described with reference to blood vessels as the subject of examination, the present invention is also suitable for application to the heart in addition to blood vessels, and is particularly applicable to minute displays of valve movements. It is conceivable that the reversal of the movement direction can be clearly displayed in color.

〔Effect of the invention〕

Since the present invention is configured as described above, the mark (31) designating the detection of the moving direction of the moving part is displayed in the tomographic image displayed on the display screen of the image display device 7 by the mark display means (30). Then, the moving direction determining means (8) determines the moving direction of the moving part using the differential image data corresponding to the position of the mark (31) displayed by the mark displaying means (30), and the color code adding means ( 9) adds a color code according to the moving direction of the moving part to the difference image data according to the output from the moving direction determining means (8), and furthermore, the image display means adds the color code adding means (
By adding the hue designated by the color hood added in step 9) to the difference image data, the difference image can be displayed in color. Thereby, the direction of movement of the moving part of the subject can be identified by a change in color. Therefore,
The direction of motion can be easily identified without relying on the afterimage effect of human vision as in the past, and individual differences among observers can be eliminated. From these points, according to the ultrasonic diagnostic apparatus of the present invention, diagnosis can be made easier.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the ultrasonic diagnostic apparatus according to the present invention, FIG. 2 is an explanatory diagram showing a specific example of the display operation of a difference image by coloring in this embodiment, and FIG. FIG. 4 is an explanatory diagram showing an example of a pattern for determining the moving direction; FIG. 5 is an illustration of the display operation of the difference image in the conventional example. FIG. 1... Probe, 2... Wave transmitting circuit, 3... Receiving circuit, 4... Video signal processing circuit, 5... DSC
l 6...Subtractor, 7...Image display device, 8.
. . . Data collection circuit for determining moving direction, 9 . . Color code addition circuit, l Oa ~ 10 n , 1
4 a ~ l 4 n -7 frame memory, 11.
...color mapping circuit, 12...adder,
17.18...Controller, 30...Movement direction detection mark setter, 31...Arrow (mark).

Claims (1)

[Claims] An ultrasonic transmitting/receiving means for transmitting and receiving ultrasonic waves to and from the subject, and a tomographic scanning means for repeatedly obtaining tomographic image data within the subject including moving parts at a predetermined period using reflected echo signals from the ultrasonic transmitting/receiving means. and means for performing calculations between the time-series images obtained by the tomographic scanning means to generate differential image data therebetween, and displaying the tomographic image data and the differential image data from the differential image data generating means. an ultrasonic diagnostic apparatus having an image display device, a means for displaying a mark specifying detection of a movement direction of a moving region in a tomographic image displayed on a display screen of the image display device; means for determining the moving direction of the moving part using differential image data corresponding to the position; means for adding a color code corresponding to the moving direction of the moving part to the differential image data according to the output of the determining means; 1. An ultrasonic diagnostic apparatus comprising: means for displaying the difference image in color by adding a hue specified by the color code added by the color code adding means to the difference image data.