Method of Displaying Elastic Image and Diagnostic Ultrasound System

• US 20080071174A1
• Filed: 08/04/2005
• Published: 03/20/2008
• Est. Priority Date: 08/05/2004
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi Medical Corporation (Hitachi, Ltd.)
• Inventors: Maeda, Masaru, Waki, Koji, Shiina, Tsuyoshi, Yamakawa, Makoto
• Granted Patent: US 8,734,351 B2
• Time in Patent Office: Days
• US Class Current: 600/442
• CPC Class Codes: A61B 8/08 Detecting organic movements or changes, e.g. tumours, cysts, swellings A61B8/02 - A61B8/06 take precedence
• 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 8/469 for selection of a region of interest
• CPC Class Codes: A61B 8/485 involving measuring strain or elastic properties
• CPC Class Codes: A61B 8/5223 for extracting a diagnostic or physiological parameter from medical diagnostic data for algorithms to analyse biomedical images G06T7/0012
• CPC Class Codes: G01S 7/52036 using analysis of echo signal for target characterisation
• CPC Class Codes: G01S 7/52042 determining elastic properties of the propagation medium or of the reflective target diagnostic techniques involving the measurement of strain A61B8/485
• CPC Class Codes: G01S 7/52071 Multicolour displays; using colour coding; Optimising colour or information content in displays, e.g. parametric imaging
• 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: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

A method of displaying an elastic image according to the present invention includes the steps of measuring ultrasound cross-section data of a cross-section region of a subject while applying compression to the subject 1 (2, 3, 4), determining distortion of tissue in the cross-section region on the basis of the ultrasound cross-section data, generating an elastic image of the cross-section region on the basis of the distortion, displaying the elastic image on a display device (7), setting a plurality of ROIs on the elastic image displayed on the display device, converting the distortion of each ROI into an index value (12), and displays the index value on the display device (8). In this way, the method enables quantitative evaluation of the hardness of body tissue of a region to be diagnosed.

Claims

1. A method of displaying an elastic image comprising the steps of:

measuring ultrasound cross-section data of a cross-section region of a subject while applying compression to the subject;

determining a physical value correlating to the elasticity of tissue in the cross-section region on the basis of the ultrasound cross-section data;

generating and displaying an elastic image of the cross-section region on the basis of the physical value;

setting a plurality of regions of interest in the displayed elastic image; and

converting the physical value of each of the regions of interest into an index value and displaying the index value together with the elastic image.

2. The method of displaying an elastic image according to claim 1, wherein the regions of interest include a first region of interest and a second region of interest set in a large region surrounding the first region of interest.

3. The method of displaying an elastic image according to claim 2, wherein the index value is a ratio of the physical values of the regions of interest.

4. The method of displaying an elastic image according to claim 3, further comprising the steps of:

determining whether or not the tissue in each region of interest is normal on the basis of the ratio of the physical values; and

displaying the determination result.

5. The method of displaying an elastic image according to claim 2, further comprising the steps of:

calculating distortion of the first region of interest and an average value of the distortion; and

calculating distortion of a region obtained by subtracting the first region of interest from the second region of interest and an average value of the distortion.

6. The method of displaying an elastic image according to claim 1, wherein the regions of interest include a first region of interest and a second region of interest set away from the first region of interest.

7. The method of displaying an elastic image according to claim 6, wherein the index value is a ratio of the physical values of the first region of interest and the second region of interest.

8. The method of displaying an elastic image according to claim 1,

wherein the regions of interest include a first region of interest set in an affected area and second and third regions of interest being set away from each other in the lateral direction of the elastic image and sandwiching the first region of interest, and

wherein the index value is a ratio of the physical value of the first region of interest and the sum of the physical values of the second and third regions of interest.

9. The method of displaying an elastic image according to claim 1, further comprising the steps of:

measuring the ultrasound cross-section data of each of left and right cross-section regions of the subject, the left and right cross-section regions being symmetrical;

generating and displaying elastic images of the left and right cross-section regions;

setting two regions of interest in each of the left and right displayed elastic images;

determining the ratio of the physical values of the two set regions of interest for each of the left and right elastic images; and

determining the ratio of the ratios of the physical values of the two regions of interest for the left and right elastic images.

10. The method of displaying an elastic image according to claim 1, further comprising the steps of:

storing the measured ultrasound cross-section data sets corresponding to a plurality of frames in a frame memory;

taking out, in order, the ultrasound cross-section data sets corresponding a plurality of pairs of frames stored in the frame memory at different measurement time periods;

computing the displacement distribution data sets for the tissue in the cross-section region corresponding to the pairs of frames;

determining a physical value correlating to the elasticity of the tissue in the cross-section region on the basis of the each displacement distribution data set;

generating and displaying a moving image of a plurality of frames of an elastic image of the cross-section region on the basis of the determined physical values;

setting the plurality of regions of interest by freezing the displayed moving elastic image;

determining average values of the physical values of the plurality of frames in the set regions of interest and the ratio of the average values; and

displaying the determined average values of the physical values and the ratio on a display device together with the moving elastic image.

11. The method of displaying an elastic image according to claim 1, further comprising the steps of:

measuring the ultrasound cross-section data for a plurality of frames;

determining the change over time of the physical value correlating to the elasticity of the tissue in the cross-section region on the basis of the plurality of frames of the ultrasound cross-section data;

generating and displaying on a display device a moving image of an elastic image of the cross-section region on the basis of the change over time of the physical value;

setting at least two regions of interest on a still image of the elastic image displayed on the display device; and

displaying on the display device the change over time of the physical value of each of the regions of interest.

12. The method of displaying an elastic image according to claim 11, further comprising the steps of:

converting the physical value of each of the regions of interest into an index value; and

displaying the change over time of the index value on the display device.

13. A diagnostic ultrasound system comprising:

an ultrasound probe;

ultrasound cross-section data measuring means for measuring ultrasound cross-section data of a cross-section region of a subject with the ultrasound probe;

signal processing means for processing the measured ultrasound cross-section data and generating a cross-sectional image;

elastic-information computing means for determining a physical value correlating to the elasticity of tissue in the cross-section region on the basis of the measured ultrasound cross-section data and generating an elastic image of the cross-section region on the basis of the physical value;

a display device for displaying the cross-sectional image and/or the elastic image;

inputting means for setting a plurality of regions of interest in the elastic image displayed on the display device; and

indexing means for converting the physical value of each of the set regions of interest into an index value and displaying the index value on the display device.

14. The diagnostic ultrasound system according to claim 13, wherein the elastic-information computing means generates a plurality of the elastic images on the basis of the plurality of ultrasound cross-section data sets measured in time sequence, displays the generated elastic images on the same screen on the display device as the displayed cross-sectional image in an overlapping manner, and displays the change in the index values of the regions of interest on the same screen.

15. The diagnostic ultrasound system according to claim 13, wherein the elastic-information computing means generates a plurality of the elastic images on the basis of a plurality of the ultrasound cross-section data sets measured in time sequence, and displays the elastic image corresponding to an assigned measurement time phase on the display device when a time phase bar for assigning the measurement time phase of the plurality of elastic images displayed on the display device is operated by the inputting means.

16. The diagnostic ultrasound system according to claim 13, wherein the regions of interest include a first region of interest and a second region of interest set in a large region surrounding the first region of interest.

17. The diagnostic ultrasound system according to claim 16, wherein the index value is the ratio of the physical values of the first region of interest and the second region of interest.

18. The diagnostic ultrasound system according to claim 17, further comprising:

determining means for determining whether or not the tissue in the region of interest is normal on the basis of the ratio of the physical values.

19. The diagnostic ultrasound system according to claim 16, wherein distortion of the first region of interest and an average value of the distortion is calculated and distortion of a region obtained by subtracting the first region of interest from the second region of interest and an average value of the distortion is calculated.

20. The diagnostic ultrasound system according to claim 17, wherein the indexing means displays a scale for the physical value on the display device and displays display marks at positions on the scale corresponding to the physical values of the first region of interest and the second region of interest.

21. The diagnostic ultrasound system according to claim 13, wherein the regions of interest include a first region of interest and a second region of interest set away from the first region of interest.

22. The diagnostic ultrasound system according to claim 21, wherein the index value is a ratio of the physical values of the first region of interest and the second region of interest.

23. The diagnostic ultrasound system according to claim 13,

wherein the regions of interest include a first region of interest set in an affected area and second and third regions of interest being set away from each other in the lateral direction of the elastic image and sandwiching the first region of interest, and

wherein the index value is a ratio of the physical value of the first region of interest and the sum of the physical values of the second and third regions of interest.

24. The diagnostic ultrasound system according to claim 13, wherein the indexing means determines average values of the physical values of the regions of interest and relates the minimum value and the maximum value of the average values into color to a lower limit value and an upper limit value of a dynamic range of color information for color conversion.

25. The diagnostic ultrasound system according to claim 24, wherein the indexing means variably sets the level of the dynamic range corresponding to an intermediate value when at least three regions of interest are set and the intermediate value is between the minimum value and the maximum value of the average values of the physical values.

26. The diagnostic ultrasound system according to claim 13, wherein

the ultrasound cross-section region data measuring means measures the ultrasound cross-section data of each of left and right cross-section regions of the subject, the left and right cross-section regions being symmetrical,

the signal processing means generates and displays on the display device cross-sectional images of the left and right cross-section regions,

the elastic image generating means generates elastic images of the left and right cross-section regions and displays the elastic images on the display device, the inputting means sets two regions of interest in each of the left and right elastic images displayed on the display device, and

the indexing means determines the ratio of the physical values of the two regions of interest in each of the left and right elastic images, determines the ratio of the ratios of the physical values of the left and right regions of interest, and displays the ratios on the display device.

27. The diagnostic ultrasound system according to claim 13, wherein

the ultrasound cross-section region data measuring means measures ultrasound cross-section data of the cross-section region of the subject corresponding to a plurality of frames while applying compression to the subject,

the elastic-information computing means determines the change over time of a physical value correlating to the elasticity of tissue of the cross-section region on the basis of the ultrasound cross-section data of the plurality of frames, and generates and displays on the display device a moving image of an elastic image of the cross-section region on the basis of the change over time of the physical value,

the inputting means sets at least two regions of interest on a still image of the elastic image displayed on the display device, and

the indexing means displays the change over time of the physical value of each of the regions of interest on the display device.

28. The diagnostic ultrasound system according to claim 27, wherein the indexing means mutually converts the physical values of the regions of interest into index values and displays the change over time of the index values on the display device.

29. The diagnostic ultrasound system according to claim 27, wherein the indexing means mutually converts the physical values of the regions of interest into index values and displays on the display device the change of an added value obtained by adding in order the index values for a plurality of frames.

30. The diagnostic ultrasound system according to claim 13, further comprising:

pressuring controlling means for supporting the ultrasound probe and for increasing or decreasing the compression applied to the subject with the ultrasound probe; and

fixing means for supporting the pressuring controlling means.