Diagnostic ultrasound imaging based on rate subtraction imaging (RSI)

• US 20020028994A1
• Filed: 01/31/2001
• Published: 03/07/2002
• Est. Priority Date: 01/31/2000
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kamiyama, Naohisa
• Granted Patent: US 6,673,019 B2
• Time in Patent Office: Days
• US Class Current: 600/437
• CPC Class Codes: A61B 8/463 characterised by displaying multiple images or images and diagnostic data on one display composite display in devices for short-range imaging with acoustic waves G01S7/52074
• CPC Class Codes: A61B 8/481 involving the use of contrast agent, e.g. microbubbles introduced into the bloodstream analysis of echo signal exploiting properties of a contrast enhancer in devices for short-range imaging with acoustic waves G01S7/52039
• CPC Class Codes: G01S 7/52038 involving non-linear properties of the propagation medium or of the reflective target
• CPC Class Codes: G01S 7/52074 Composite displays, e.g. split-screen displays; Combination of multiple images or of images and alphanumeric tabular information
• CPC Class Codes: G01S 7/52085 Details related to the ultrasound signal acquisition, e.g. scan sequences control of medical diagnostic ultrasound devices A61B8/54

Abstract

In a diagnostic ultrasound apparatus, an ultrasound pulse signal is transmitted two times in each of the rasters on a region to be scanned. Subtraction between echo signals received at each time of transmission is made to obtain a difference signal. Either one of the echo signals and the difference signal are produced into individual tomographic images, independently of each other. The produced individual tomographic images are displayed with a superposed manner one on the other or parallel-arranged manner. This allows contrast echo imaging to be conducted on a rate subtraction imaging technique. Minute blood flows are depicted distinguishably from tissue surrounding those flows in a steady manner.

Claims

1. A diagnostic ultrasound apparatus for obtaining an image of a region to be scanned by scanning an object with a beam-shaped ultrasound signal, an ultrasound contrast agent being injected into the object, comprising:

scanning means for transmitting the ultrasound signal a plurality of times in each direction composing the region to be scanned and receiving an echo signal in response to each transmission;

subtracting means for obtaining a difference signal by performing subtraction between the echo signals received with two times of transmission among the plurality of times of transmission;

producing mean for independently producing both of the echo signal received with any time of transmission of the plurality of times of transmission and the difference signal into individual tomographic images; and

displaying means for displaying the individual tomographic images at the same time.

2. The diagnostic ultrasound apparatus of claim 1, wherein the plurality of times of transmission is two times of transmission in each raster composing each direction.

3. The diagnostic ultrasound apparatus of claim 2, wherein the producing means has processing means for processing any of a first echo signal and a second echo signal received with the two times of transmission and the difference signal under processing conditions mutually independent of each other into data of two tomographic images.

4. The diagnostic ultrasound apparatus of claim 3, wherein the processing conditions include at least one of a reception gain, a dynamic range, cut-off frequency and bandwidth of an echo filter, and a frame-to-frame after-image processing.

5. The diagnostic ultrasound apparatus of claim 3, wherein the processing conditions include at least one of a correction processing technique and a color encoding technique performed when mapping intensities of the echo signal on a video screen.

6. The diagnostic ultrasound apparatus of claim 1, wherein the displaying means has means for displaying the individual tomographic images in mutually different colors.

7. The diagnostic ultrasound apparatus of claim 1, wherein the displaying means is means for displaying the individual tomographic images with either one tomographic image superposed on the other tomographic image.

8. The diagnostic ultrasound apparatus of claim 7, wherein the displaying means is means for displaying the tomographic image based on the difference signal, which serves as the other tomographic image, superposed on the tomographic image based on the echo signal, which servers as the one tomographic image.

9. The diagnostic ultrasound apparatus of claim 8, wherein the displaying means is means for displaying, of the one and other images, either one image in gray scales and the remaining image in colors.

10. The diagnostic ultrasound apparatus of claim 8, wherein the displaying means is means for displaying the one and other images in mutually different colors.

11. The diagnostic ultrasound apparatus of claim 1, wherein the displaying means is means for displaying the individual tomographic images in parallel with each other on a screen.

12. The diagnostic ultrasound apparatus of claim 1, wherein the producing means has image memorizing means capable of individually memorizing image data of the individual tomographic images and individually reading out the image data thereof.

13. The diagnostic ultrasound apparatus of claim 12, wherein the displaying means has means for individually reading out the image data of the tomographic images from the image memorizing means and mans for commanding a switchover of display modes consisting of superposed display of the individual tomographic images, parallel display of the individual tomographic images, and sole display of either one of the individual tomographic images on the bases on the read-out image data.

14. The diagnostic ultrasound apparatus of claim 13, wherein the displaying means include means for independently setting at least one of a correction processing technique and color encoding technique accordingly to which of the echo signal and the difference signal corresponds to the read-out image data and mapping the image data on a video screen.

15. The diagnostic ultrasound apparatus of claim 1, wherein the ultrasound contrast agent is a contrast agent of which main constituent is microbubbles, and the scanning means is means for additionally transmitting an ultrasound signal to excite the microbubbles in each direction.

16. The diagnostic ultrasound apparatus of claim 1, wherein the additional transmission of the exciting ultrasound signal interleaves in time between two times of transmission selected from the plurality of times of transmission.

17. The diagnostic ultrasound apparatus of claim 1, wherein the displaying means has means for commanding a switchover of display modes consisting of superposed display of the individual tomographic images, parallel display of the individual tomographic images, and sole display of either one of the individual tomographic images.

18. The diagnostic ultrasound apparatus of claim 1, wherein the echo signal experiencing the subtraction executed by the subtraction means is a radio frequency signal of the echo signal before detected.

19. The diagnostic ultrasound apparatus of claim 8, wherein the displaying means has superposition control means that is changeable in a superposition balance of intensity when the other tomographic image is superposed on the one tomographic image.

20. The diagnostic ultrasound apparatus of claim 19, wherein the superposition control means has manual-change commanding means capable of manually changing the superposition balance.

21. A diagnostic ultrasound apparatus for obtaining an image of a region to be scanned by scanning an object with a beam-shaped ultrasound signal, an ultrasound medium being injected into the object:

scanning means for transmitting the ultrasound signal a plurality of times in each direction composing the region to be scanned and receiving an echo signal in response to each transmission;

subtracting means for obtaining a difference signal by performing subtraction between the echo signals received with two times of transmission among the plurality of times of transmission;

addition means for obtaining an average signal by performing average between the echo signals received with two times of transmission among the plurality of times of transmission;

producing mean for independently producing both of the difference signal and the average signal into individual tomographic images; and

displaying means for displaying the individual tomographic images at the same time.

22. The diagnostic ultrasound apparatus of claim 21, wherein the plurality of times of transmission is two times of transmission in each raster composing each direction.

23. The diagnostic ultrasound apparatus of claim 22, wherein the producing means includes processing means for processing the average signal and the difference signal with processing conditions mutually independent of each other into data of two tomographic images.

24. The diagnostic ultrasound apparatus of claim 21, wherein the displaying means is means for displaying the individual tomographic images in either one of a superposition manner and a parallel manner.

25. The diagnostic ultrasound apparatus of claim 21, wherein the subtraction means is means for performing the subtraction of the echo signal received by the first-time transmission of the plurality of times of transmission and the echo signal received by any-time transmission selected from the second-time or later transmission of the plurality of times of transmission, and

the addition means is means for performing the addition of the echo signal received by the first-time transmission of the plurality of times of transmission and the echo signal received by any-time transmission selected from the second-time or later transmission of the plurality of times of transmission.

29. The diagnostic ultrasound apparatus of claim 28, wherein the plurality of times of transmission is two times of transmission in each raster composing each direction.

30. The diagnostic ultrasound apparatus of claim 29, wherein the producer has a processor for processing any of a first echo signal and a second echo signal received with the two times of transmission and the difference signal under processing conditions mutually independent of each other into data of two tomographic images.

31. The diagnostic ultrasound apparatus of claim 28, wherein the display is configured to display the individual tomographic images with either one tomographic image superposed on the other tomographic image.

32. The diagnostic ultrasound apparatus of claim 31, wherein the display is changeable in a superposition balance of intensity when the other tomographic image is superposed on the one tomographic image.

33. The diagnostic ultrasound apparatus of claim 32, wherein the display is configured to be capable of manually changing the superposition balance.

34. The diagnostic ultrasound apparatus of claim 28, wherein the echo signal experiencing the subtraction executed by the subtracter is a radio frequency signal of the echo signal before detected.

26. An ultrasound imaging method for obtaining an image of a region to be scanned by scanning an object with a beam-shaped ultrasound signal, an ultrasound contrast agent being injected into the object, comprising the steps of:

transmitting the ultrasound signal a plurality of times in each direction composing the region to be scanned and receiving an echo signal in response to each transmission;

obtaining a difference signal by performing subtraction of the echo signals received with two times of transmission among the plurality of times of transmission;

independently producing both of the echo signal received with any time of transmission of the plurality of times of transmission and the difference signal into individual tomographic images; and

displaying the individual tomographic images at the same time.

27. An ultrasound imaging method for obtaining an image of a region to be scanned by scanning an object with a beam-shaped ultrasound signal, an ultrasound contrast agent being injected into the object, comprising the steps of:

transmitting the ultrasound signal a plurality of times in each direction composing the region to be scanned and receiving an echo signal in response to each transmission;

calculating a difference signal by performing subtraction of the echo signals received with two times of transmission among the plurality of times of transmission;

calculating an average signal by performing average between the echo signals received with two times of transmission among the plurality of times of transmission;

independently producing both of the difference signal and the average signal into individual tomographic images; and

displaying the individual tomographic images at the same time.

28. A diagnostic ultrasound apparatus for obtaining an image of a region to be scanned by scanning an object with a beam-shaped ultrasound signal, an ultrasound contrast agent being injected into the object:

an ultrasound probe for transmitting and receiving the ultrasound signal;

a transmitter for exciting the ultrasound probe responsively to each rate pulse so as to cause the ultrasound probe to output the ultrasound signal;

a receiver for delaying and adding an echo signal received by the ultrasound probe;

a controller for causing the transmitter to transmit the ultrasound signal a plurality of times in each direction composing the region to be scanned and causing the receiver to receive the echo signal in response to each transmission;

a subtracter for obtaining a difference signal by performing subtraction between the echo signals received with two times of transmission among the plurality of times of transmission;

a producer for independently producing both of the echo signal received with any time of transmission of the plurality of times of transmission and the difference signal into individual tomographic images; and

a display for displaying the individual tomographic images at the same time.