JP3263171B2 - Ultrasound diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic diagnostic apparatus for displaying the moving speed of a moving organ such as a myocardium or a blood vessel wall in color, and more particularly to a technique for recognizing a difference in motion before and after a load is applied.

[0002]

2. Description of the Related Art In recent years, an ultrasonic diagnostic apparatus has been widely used in the development of a medical diagnostic apparatus. In such an ultrasonic diagnostic apparatus, an apparatus that obtains a blood flow velocity using a Doppler method and displays the blood flow velocity in color is realized. In recent years, as shown in Japanese Patent Application No. 4-265052, the motion velocity of a moving organ such as a myocardium or a blood vessel wall is also obtained by the Doppler method, and this is displayed in color, so that, for example, the myocardium can be normalized. It has been proposed to diagnose whether it is moving.

According to this method, various kinds of motion information of the myocardium and the blood vessel wall can be displayed in real time and in various colors, and quantitative analysis becomes possible.

[0004]

Incidentally, a stress echo method using an ultrasonic diagnostic apparatus has been receiving attention. In this method, for example, a subject is jogged, images of the myocardium are taken before and after jogging, and these are compared to determine an abnormal site.

However, the aforementioned Japanese Patent Application No. Hei 4-26505.
The method described in No. 2 does not refer to the stress echo method. Conventionally, when diagnosing ischemic disease or the like by the stress echo method, the B mode or the M mode is used.
The observation of the left ventricular wall motion by the mode image is performed.
Further, in order to avoid such a diagnosis relying on the subject's subjectivity, a method using a dedicated left ventricular wall motion analyzer is applied.

[0006] However, such a method has a drawback in that it requires tracing of the endocardium and the like, which requires complicated operations.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to utilize a method of capturing a moving velocity image of a moving organ such as a myocardium or a blood vessel wall. It is an object of the present invention to provide an ultrasonic diagnostic apparatus capable of easily and accurately performing a diagnosis by a stress echo method.

[0008]

In order to achieve the above object, the present invention provides an ultrasonic echo signal obtained by scanning a region including a moving organ such as a myocardium or a blood vessel wall with an ultrasonic beam and receiving a Doppler shift. Scanning means for obtaining the above, a speed calculating means for calculating the moving speed of the organ based on the ultrasonic echo signal obtained by the scanning means, and a display means for displaying the moving speed calculated by the speed calculating means in color. In the ultrasonic diagnostic apparatus, means for scanning before and after applying a load to the moving organ to obtain a motion speed before and after the load, and a parameter value representing a change amount of the motion speed before and after the load from the obtained motion speed before and after the load And a means for performing color display based on the value of the parameter.

[0009]

According to the present invention constructed as described above, the movement speeds of the moving organs are determined before and after the application of a load such as jogging or drug administration, and the differences and ratios are calculated based on the obtained speeds. By performing color display based on the calculation result, it is possible to know a change before and after the load is applied. For example, if a part that was operating normally before applying a load changes its motion due to the application of a load, the part can be quickly known.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first example of an ultrasonic diagnostic apparatus to which the present invention is applied.
FIG. 3 is a block diagram illustrating a configuration of an example.

As shown in FIG. 1, the ultrasonic diagnostic apparatus 1
Reference numeral 0 denotes an ultrasonic probe 11 for transmitting and receiving an ultrasonic signal to and from a subject, and an apparatus body 12 for driving the ultrasonic probe 11 and processing a received signal of the ultrasonic probe 11.
An ECG (electrocardiograph) 13 connected to the apparatus main body 12 and detecting electrocardiographic information; and an operation panel 14 connected to the apparatus main body 12 and capable of outputting instruction information from an operator to the apparatus main body. .

The apparatus main body 12 can be broadly classified into an ultrasonic probe system, an ECG system, and an operation panel system depending on the type of a signal path to be handled. As a probe system,
An ultrasonic transmission / reception unit 15 connected to the ultrasonic probe 11 is provided.
Mode DSC (Digital Scan Converter) Unit 1
6, a B-mode frame memory (FM) 17, a memory synthesizing unit 18 and a display unit 19, and also connected to the ultrasonic probe 11, the color flow mapping (C
FM), phase detector 20, filter 21, frequency analyzer 22, hold processing circuit 50, DSC for CFM
Unit 55, first and second CFM frame memories 53,
54, and an inter-frame change amount calculation circuit 55.

As an ECG system, an ECG amplifier 40 connected to the ECG 13 is provided.
Trigger signal generator 41 and reference data memory 42 connected to the output side. Further, the operation panel system includes a CPU for inputting operation information from the operation panel 14.
(Central processing unit) 43 and a timing signal generator 44 under the control of the CPU 43. Note that C
The PU 43 can supply an ROI (region of interest) setting signal instructed by the operator via the operation panel 14 to each component required for ROI setting.

In this embodiment, the ultrasonic probe 1
1 and the ultrasonic transmission / reception unit 15 form the scanning unit of the present invention, and the phase detection unit 20, the filter unit 21, and the frequency analysis unit 2
2 and the vector calculation unit 23 form the speed calculation means of the present invention. The CFM DSC unit 24, the CFM frame memory 25, the memory synthesizing unit 18, and the display unit 19 form a display unit of the present invention.

The ultrasonic probe 11 has a built-in transducer in which a plurality of strip-shaped piezoelectric vibrators are arranged. Each piezoelectric vibrator can be excited by a drive signal from the ultrasonic transmission / reception unit 15. By controlling the delay time of each driving signal, the scanning direction can be changed to enable sector electronic scanning. The delay time pattern of the ultrasonic transmission / reception unit 15 is controlled by the CPU 43 using a reference signal sent from a timing signal generator 44 described later as a reference time. The ultrasonic transmission / reception unit 15 outputs to the ultrasonic probe 11 a drive voltage signal whose delay time pattern is controlled according to the scanning direction. The ultrasonic probe 11 receiving this drive voltage signal converts the voltage signal into an ultrasonic signal in the transducer. The converted ultrasonic signal is transmitted toward the organ of the subject. The transmitted ultrasonic signal is reflected by each tissue including the heart, and returns to the ultrasonic probe 11 again. So, probe 1
In the transducer 1, the reflected ultrasonic signal is converted again into a voltage signal (echo signal), and the echo signal is output to the ultrasonic transmission / reception unit 15.

The signal processing circuit of the ultrasonic transmission / reception unit 15 delays and adds a phase to the input echo signal in the same manner as at the time of transmission to generate an echo beam signal equivalent to narrowing the ultrasonic beam in the scanning direction. Generate. After the phasing-added echo beam signal is detected, the B-mode DS
It is output to C section 16. The DSC unit 16 converts the echo data of the ultrasonic scanning into the data of the standard television scanning, and outputs the data to the memory synthesizing unit 18. In parallel with this,
The mode DSC unit 16 stores a plurality of image data in an arbitrary cardiac phase in the B-mode frame memory.

On the other hand, the echo signal processed by the ultrasonic transmission / reception unit 15 is also output to the phase detection unit 20. The phase detector 20 includes a mixer and a low-pass filter. The echo signal reflected from a portion that is exercising, such as the myocardium, has a Doppler shift (Doppler frequency) at its frequency due to the Doppler effect. The phase detector 20 performs phase detection on the Doppler frequency, and outputs only a low-frequency Doppler signal to the filter 21.

The filter unit 21 uses the fact that the magnitude of the movement velocity has a relationship of “myocardium <valve <blood flow” to extract valve movements other than the heart wall, blood flow, etc., from the phase-detected Doppler signal. Unnecessary Doppler components are removed, and Doppler signals of the myocardium in the ultrasonic beam direction are detected efficiently. In this case, the filter unit 21 functions as a low-pass filter.

The above filter unit has already been put into practical use.
It is also mounted on a color Doppler tomography apparatus for obtaining blood flow information. In the case of a color Doppler tomography apparatus that obtains this blood flow information, a signal in which the Doppler signals of the blood flow, the heart wall, and the valve motion are mixed functions as a high-pass filter to remove the Doppler signals other than the blood flow. I have. For this reason, the filter section can switch between a low-pass filter and a high-pass filter according to the purpose of the device, so that versatility can be enhanced.

The Doppler signal filtered by the filter unit 21 is output to the next-stage frequency analysis unit 22. The frequency analysis unit 22 applies a FFT method and an autocorrelation method, which are typical frequency analysis methods of a blood flow signal (Doppler signal) used in ultrasonic Doppler blood flow measurement,
Observation time (time window) for each sample volume
Calculate the average speed and the maximum speed within. More specifically, for example, using the FFT method or the autocorrelation method, the average Doppler frequency of each scan point (that is, the average velocity of the movement of the observation target at that point) and the variance value (the degree of disturbance of the Doppler spectrum)
And the maximum value of the Doppler frequency (that is, the maximum speed of the movement of the observation target at that point) and the like are calculated in real time using the FFT method. The analysis result of the Doppler frequency is used as color Doppler information as the next-stage hold processing circuit 50.
And temporarily stored here.

Here, the hold processing circuit is a circuit having a function of obtaining the maximum contraction speed of each pixel for each heartbeat (max hold processing).

Thereafter, the contents stored in the hold processing circuit 50 are output to the CFM DSC unit 56. This CFM
The DSC unit 56 includes a DSC 51 for converting the scanning method and a color circuit 52 having a look-up table for colorizing the speed data. For this reason, the output of the hold processing circuit 50 is converted by the DSC 51 from the ultrasonic scanning signal into a standard television scanning signal and the color circuit 5
The data is converted into color display data by 2 and the converted signal is output to the memory synthesizing unit 18.

The DSC 51 of the CFM DSC unit 56
Calculates a maximum contraction speed V _max (0, x, y) of each pixel (two-dimensional coordinates (x, y)) within the heartbeat before applying a load to the subject. First CF
It is stored in the M frame memory 53. Further, the maximum contraction speed is determined for each heartbeat while applying a load to the subject, and the maximum contraction speed of each pixel at the nth heartbeat is calculated as V _max (n, x, y)
In the second CFM frame memory 54.

Thereafter, in the inter-frame change amount calculation circuit 55, V _max (0,
x, y), V is obtained from the second CFM frame memory 54.
_max (n, x, y) is read out, and one of the following three parameter equations is calculated.

V _max (n, x, y) / V _max (0, x, y) (1) V _max (n, x, y) −V _max (0, x, y) (2) (V _max (n, x, y) −V _max (0, x, y)) / V _max (0, x, y) (3) The color and brightness are changed in accordance with, and this is displayed on the screen. The display image is updated for each heartbeat because the data is updated for each heartbeat in the hold processing circuit 50.

For example, when the sign of the amount of change in the above equation (3) is represented by "+" in red, "-" in blue, and the magnitude of the amount of change by luminance, a patient with normal wall motion before loading is expressed. However, when a load is applied, the contractile force is displayed in red to increase the pump function of the heart in the normal myocardium, but when a myocardial ischemia is induced and a site of reduced wall motion appears, the region is displayed in blue. It can be easily distinguished from normal myocardium.

When a patient who has a portion where wall motion has decreased before loading is examined for recovery of contractility due to drug administration or the like, the region where the contractility has recovered is displayed in bright red and the myocardium in this portion is displayed. Shows that vaibility remains. On the other hand, if the contraction force does not recover, as indicated by reference numeral 101 in FIG.
Since it is displayed in black and blue, it is easy to see that the myocardium in this part is completely necrotic.

As described above, in this embodiment, the difference between before and after the load is applied is displayed easily and with high accuracy.
An accurate diagnosis can be made in real time.

FIG. 2 is a block diagram showing a second embodiment of the present invention. In this example, the exercise speed is obtained in synchronization with the cardiac cycle of the heartbeat. FIG. 2 differs from the first embodiment in that the hold processing circuit 50 in FIG. 1 shown in the first embodiment is not required.

In this embodiment, an appropriate heartbeat is selected before applying a load, and each frame and each pixel (2
Motion velocity V (0, m0, x, dimensional coordinate (x, y))
y) and the cardiac cycle (electrocardiogram RR interval) T0 in the heartbeat
Is obtained and stored in the first CFM frame memory 53. Here, m0 is the number of the ultrasonic scan frame based on the R wave of the electrocardiogram before loading. It is. Next, the exercise speed is determined for each heartbeat while applying a load, and the exercise speed of each pixel at the nth heartbeat is defined as V (n ,, m1, x, y).
In the CFM frame memory 54. Where m
No. 1 is the number of the ultrasonic scan frame based on the R wave of the electrocardiogram under load. The cardiac cycle T _n for each heartbeat also determined at the same time. Then, the first CFM frame memory 53
More V (0, m0, x, y), V max from the second CFM frame memory 54 (n, m1, x, y) 3 Formula below in inter-frame variation calculation circuit 55 been read at the same time Is calculated.

V (n, m1, x, y) / V (0, m0, x, y) (4) V (n, m1, x, y) −V (0, m0, x, y) (5) (V (n, m1, x, y) -V (0, m0, x, y)) / V (0, m0, x, y) In general, the heart rate is Care must be taken when comparing myocardial movement velocities in the same cardiac phase before and during loading because they change before and after loading. Here, the frame number of the n-th heartbeat under load is set. A frame m0 of the same cardiac phase before the load corresponding to m1 is obtained as follows.

M0 = m1 × (T0 / Tn) (7) Then, the color or luminance is changed in the color circuit 52 in accordance with the magnitude or sign of the amount of change obtained above, and a two-dimensional tomographic image as shown in FIG. (B mode image) is superimposed and displayed. The image of the change amount can be displayed in real time during the load.

Next, an example of a display method for comparing changes before and after applying a load will be described. First, in the myocardium before the load is applied, the velocity average value is obtained radially from the center of the heart chamber and stored in the memory corresponding to each part, and the same calculation is performed after the load is applied. V2 / v1 for each part before and after loading
Alternatively, an operation such as v2-v1 or (v2-v1) / v1 is performed, and the result is displayed as shown in FIG. As shown in the drawing, in this display example, the speed image before the load and the speed image after the load are displayed, and, as indicated by reference numeral 62, the calculation results of the before and after the loads are displayed. In this image, the vertical axis indicates a region, and the horizontal axis indicates a frame (time), and luminance modulation is performed according to the calculation result. It is also possible to assign colors, hues and tones according to the calculation results.

By displaying the color bar 61, the magnitude of the change can be recognized by comparing the color and the luminance.

In order to apply the above-mentioned display method, it is necessary to match the spatial positions of the images before and after the load. It suffices to find and match these centers of gravity.

Further, as another method of spatial positioning, when performing a diagnosis after loading as shown in FIG. 4, a real-time reproduction of an image before loading is performed on a screen, and a doctor looks at the image while watching the image. Perform manual alignment.

Although the velocity is used as the movement velocity of the myocardium in the above-described embodiments, the present invention may use acceleration instead of velocity in each embodiment.

In this case, at the output end of the frequency analyzing unit 22, an acceleration calculating unit for calculating the acceleration of the movement of the myocardium is provided, and the output of the acceleration calculating unit is output to the next-stage hold processing circuit 50 or the CFM DSC unit 56. May be output.

The acceleration calculation section calculates the acceleration from the analysis result of the frequency analysis section 22, that is, the motion velocity of each sample volume in the ultrasonic beam direction. Specifically, when attention is focused on the sample volume of ultrasound scans region, when the detected speed thereof to detect the speed of the sample volume V _n-1, n-th in the (n-1) th ultrasound frame is V _n The motion acceleration of the myocardium at the position of the sample volume is approximately determined by the following equation.

The _{dV / dt (V n -V n} -1) / T where, T is a scanning period of the ultrasound frame. The acceleration calculation based on this equation is performed for each sample volume.

The acceleration data of each sample point calculated by the acceleration calculator in this way is stored in the CFM DSC 5
At step 6, processing for color display is performed. The display of the acceleration is also divided into a case where only the magnitude (absolute value) of the acceleration is displayed and a case where the direction of the motion and the magnitude of the acceleration are displayed. The expression method for each display mode can be handled by replacing the speed display item in the above-described embodiment with the acceleration display item.

[0042]

As described above, according to the present invention, when diagnosing a moving organ such as a myocardium or a blood vessel wall of a subject by the stress echo method, a motion velocity image taken before applying a load is used. Since the difference and ratio with the motion velocity image taken after applying the load are obtained, and this calculation result is displayed in color,
By applying a load, it is possible to easily recognize a portion where an abnormality occurs in the exercise, and it is possible to obtain an effect that diagnostic accuracy is significantly improved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an ultrasonic diagnostic apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an ultrasonic diagnostic apparatus according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a display example for comparing changes before and after a load.

FIG. 4 is an explanatory diagram when performing image alignment before and after loading.

FIG. 5 is a diagram showing an example in which a portion of the myocardium where wall motion has been reduced is displayed.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 ultrasonic diagnostic apparatus 11 ultrasonic probe 12 apparatus main body 15 ultrasonic transmitting / receiving unit 50 hold processing circuit 51 DSC (digital scan converter) 52 color circuit 53 first CFM frame memory 54 second CFM frame memory 55 between frames Variation calculation circuit 56 DSC unit for CFM

Continuation of front page (56) References JP-A-58-20158 (JP, A) JP-A-58-200737 (JP, A) JP-A-61-181449 (JP, A) JP-A-62-62268 (JP, A) JP-A-2-4339 (JP, A) JP-A-2-92347 (JP, A) JP-A-2-193650 (JP, A) JP-A-3-170133 (JP, A) JP-A-4-215251 (JP, A) JP-A-4-176447 (JP, A) JP-A-4-208143 (JP, A) JP-A-5-84246 (JP, A) JP-A-5-337110 (JP, A A) JP-A-6-78921 (JP, A) JP-A-6-114059 (JP, A) JP-A-6-233767 (JP, A) WO 91/19457 (WO, A1) Hideki Mitani, Akira Kurita , Localization of coronary artery lesions in patients with old myocardial infarction by exercise echocardiography, Proceedings of the 60th Annual Meeting of the Japanese Society of Sonographers, 1992 April 25, 201-202 Masako Fukui et al., Dobuta Examination of diagnosability of coronary artery lesions in patients with ischemic heart disease by min-loaded tomography echocardiography, Proceedings of the 61st Annual Meeting of the Japanese Society of Ultrasonics, 1992 October 20, 179-180 Naito Fumi et al., Evaluation of Ultrasonic Myocardial Tissue Properties by Dobutamine Loading, Proceedings of the 61st Annual Meeting of the Japanese Society of Ultrasonics, The Japanese Society of Ultrasonics, October 1992 20th, 409-410 (58) Field surveyed (Int. Cl. ⁷ , DB name) A61B 8/00

Claims (3)

(57) [Claims] 1. A scanning unit for scanning an area including a moving organ such as a myocardium or a blood vessel wall with an ultrasonic beam to obtain an ultrasonic echo signal subjected to a Doppler shift, and an ultrasonic echo obtained by the scanning unit. An ultrasonic diagnostic apparatus comprising: a speed calculating unit that calculates a moving speed of the organ based on a signal; and a display unit that displays a color of the moving speed calculated by the speed calculating unit. Means for obtaining a movement speed before and after the load by scanning with; a means for obtaining a parameter value representing an amount of change in the movement speed before and after the load from the obtained movement speed before and after the load; and performing color display based on the parameter value And an ultrasonic diagnostic apparatus. 2. The ultrasonic diagnostic apparatus according to claim 1, wherein the movement speed is a speed or an acceleration. 3. The parameter is: (motion speed after load) − (motion speed before load) / (motion speed after load) / (motion speed before load) or ((motion speed after load) − (Motion speed before load)) /
The ultrasonic diagnostic apparatus according to claim 1, wherein: (exercise speed before load).