Adjunctive ultrasound processing and display for breast cancer screening

• US 20030212327A1
• Filed: 11/27/2002
• Published: 11/13/2003
• Est. Priority Date: 11/24/2000
• Status: Active Grant

• Current Assignee: U-System Inc. (General Electric Company)
• Original Assignee: U-System Inc. (General Electric Company)
• Inventors: Wang, Shih-Ping, Rao, Fangyi, Chin, Donald, Karssemeijier, Nico
• Granted Patent: US 7,597,663 B2
• Time in Patent Office: Days
• US Class Current: 600/437
• CPC Class Codes: A61B 6/463 characterised by displaying multiple images or images and diagnostic data on one display
• CPC Class Codes: A61B 6/502 for diagnosis of breast, i.e. mammography
• CPC Class Codes: A61B 6/5241 combining overlapping images of the same imaging modality, e.g. by stitching
• CPC Class Codes: A61B 6/5247 combining images from an ionising-radiation diagnostic technique and a non-ionising radiation diagnostic technique, e.g. X-ray and ultrasound
• CPC Class Codes: A61B 6/563 involving image data transmission via a network
• CPC Class Codes: A61B 8/0825 for diagnosis of the breast, e.g. mammography
• CPC Class Codes: A61B 8/406 using means for diagnosing suspended breasts
• CPC Class Codes: A61B 8/4281 characterised by sound-transmitting media or devices for coupling the transducer to the tissue
• CPC Class Codes: A61B 8/4405 Device being mounted on a trolley
• 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 8/464 involving a plurality of displays
• CPC Class Codes: A61B 8/465 adapted to display user selection data, e.g. icons or menus
• CPC Class Codes: A61B 8/466 adapted to display 3D data 3D imaging and stereoscopic displays in devices for short-range imaging with acoustic waves G01S15/8993 and G01S7/52068, respectively; 3D image rendering G06T15/00; manipulating 3D models for computer graphics G06T19/00
• CPC Class Codes: A61B 8/467 characterised by special input means
• CPC Class Codes: A61B 8/5215 involving processing of medical diagnostic data
• CPC Class Codes: A61B 8/5238 for combining image data of patient, e.g. merging several images from different acquisition modes into one image for image registration algorithms G06T7/30
• CPC Class Codes: A61B 8/565 involving data transmission via a network

Abstract

An adjunctive ultrasound mammography system and associated methods are described comprising an adjunctive ultrasound display configured for quick, intuitive, interactive viewing of data derived from volumetric ultrasound scans, the data being displayed near a conventional x-ray mammogram display. Preferred embodiments for navigating among a thick-slice image array, a selected enlarged thick-slice image, and planar ultrasound views are described, including a preferred embodiment in which the planar ultrasound views are updated in real time as a cursor is moved across an active thick-slice image. In one preferred embodiment the thick-slice images are inverted prior to display, with non-breast areas of the image preferably segmented out and reset to dark. The inverted thick-slice images are of more familiar significance to radiologists having years of expertise in analyzing conventional x-ray mammograms. For example, the inverted thick-slice images allow benign features to be more easily dismissed as compared to non-inverted thick-slice images. Preferred embodiments for computing thick-slice image values from the volumetric scan data are also described that emphasize larger mass lesions in the resulting thick-slice images, and that compensate for mass lesions that straddle thick-slice region borders.

Claims

1. A method for facilitating breast cancer screening, comprising:

acquiring raw ultrasound slices representing sonographic properties of a breast;

forming a volumetric representation of said sonographic properties from said raw ultrasound slices;

computing a two-dimensional thick-slice ultrasound image from said volumetric representation, said thick-slice ultrasound image representing said sonographic properties within a slab-like subvolume of the breast having a thickness greater than about 2 mm and less than about 20 mm;

displaying said thick-slice ultrasound image to a user during a viewing session;

computing a planar ultrasound image from said volumetric representation, said planar ultrasound image representing said sonographic properties along a substantially planar portion of the breast substantially nonparallel to said slab-like subvolume; and

electronically displaying said planar ultrasound image to the user during the viewing session.

2. The method of claim 1, wherein said thick-slice ultrasound image and said planar ultrasound image are simultaneously displayed to the user near each other to facilitate back-and-forth viewing therebetween.

3. The method of claim 2, wherein said slab-like subvolume is substantially parallel to a standard x-ray mammogram view plane.

4. The method of claim 1, said slab-like subvolume being substantially parallel to a standard x-ray mammogram view plane, further comprising displaying an x-ray mammogram image of the breast taken along said standard x-ray mammogram view plane to said user during the viewing session.

5. The method of claim 4, wherein said thick-slice ultrasound image, said planar ultrasound image, and said x-ray mammogram image are simultaneously displayed to the user near each other to facilitate back-and-forth viewing thereamong.

6. The method of claim 5, wherein said x-ray mammogram is displayed as an x-ray film on a backlit display.

7. The method of claim 6, wherein said thick-slice ultrasound image is electronically displayed.

8. The method of claim 7, wherein said planar ultrasound image is displayed on a high-brightness CRT monitor positioned adjacent to said thick-slice ultrasound image.

9. The method of claim 8, wherein said thick-slice ultrasound image is displayed on an LCD monitor.

10. The method of claim 9, wherein said thick-slice ultrasound image is enlarged or reduced to have the same spatial dimensions as the x-ray mammogram image.

11. The method of claim 1, said raw ultrasound slices comprising values according to a conventional ultrasound display convention in which higher reflection readings are displayed as brighter and lower reflection readings displayed as darker, further comprising inverting said thick-slice image to an inverted ultrasound display convention in which higher reflection readings are displayed as darker and lower reflection readings displayed as brighter.

12. The method of claim 11, further comprising:

segmenting said thick-slice image into a first region lying inside the breast and a second region lying outside the breast, said second region having bright pixels directly after said inverting; and

resetting said second region pixels to dark values, the resulting thick-slice image thereby being more reminiscent of a conventional x-ray mammogram image in said second region.

13. A method for computing a two-dimensional thick-slice ultrasound image from a volumetric ultrasound representation of a breast, said volumetric ultrasound representation comprising voxels, said thick-slice ultrasound image comprising pixels and corresponding to a first slab-like subvolume of the breast lying between a first border plane and a second border plane thereof, comprising:

identifying for each pixel location in the thick-slice ultrasound image a first voxel set corresponding to a voxel column in said volumetric ultrasound representation passing through that pixel location and extending from the first border plane to the second border plane;

computing one or more statistical properties of said first voxel set; and

computing an output value for that pixel location using said one or more statistical properties of said first voxel set.

14. The method of claim 13, said one or more statistical properties of said first voxel set incurring changes across different pixel locations in mass localities that are more significant for masses greater than a preselected size of interest and that are less significant for masses smaller than said preselected size of interest, mass lesions greater than said preselected size of interest being emphasized and mass lesions smaller than said preselected size of interest being de-emphasized in said thick-slice image.

15. The method of claim 14, said computing an output value comprising:

computing a histogram of values of said first voxel set;

computing at least a portion of a cumulative distribution function from said histogram;

determining a first pixel level for which said cumulative distribution function is equal to a threshold, said threshold being a function of said preselected size of interest; and

setting said output value equal to said first pixel level.

16. The method of claim 15, said threshold being a fixed value equal to a preselected constant K times a ratio of (i) said preselected size of interest, to (ii) a distance between said first and second border planes.

17. The method of claim 16, wherein K is between about 0.20 and about 0.45.

18. The method of claim 15, said threshold being variable for different pixel locations in said thick-slice ultrasound image, said threshold being equal to a variable multiplier K times a ratio of (i) said preselected size of interest, to (ii) a distance between said first and second border planes.

19. The method of claim 18, wherein values of K are maintained within a range of about 0.20 to about 0.45.

20. The method of claim 13, the breast further having a second slab-like subvolume immediately adjacent to the first slab-like volume, further comprising:

identifying for each pixel location in the thick-slice ultrasound image a second voxel set corresponding to said voxel column extending from a first intermediate elevation in said first slab-like volume to a second intermediate location is said second slab-like volume, said first and second voxel sets having about the same number of voxels;

computing said one or more statistical properties of said second voxel set;

computing an alternative result for that pixel location using said one or more statistical properties of said second voxel set; and

if said alternative result indicates an ultrasound echo intensity less than that indicated by said output value, resetting said output value to said alternative result.

21. The method of claim 20, said volumetric ultrasound representation being formed from scans taken during a sweep of an ultrasound probe across the breast, wherein said second slab-like volume is closer to a locus of said ultrasound probe sweep than said first slab-like volume.

22. A method for interactive display of adjunctive ultrasound mammography in a breast cancer screening environment, comprising:

electronically displaying to a user an array of thick-slice ultrasound images, each thick-slice ultrasound image representing sonographic properties of a slab-like subvolume of the breast having a thickness greater than about 2 mm and less than about 20 mm;

receiving a first command from the user that selects a first member of said thick-slice ultrasound image array and a first location thereon;

responsive to said first command, electronically displaying an enlarged thick-slice image view of said selected first member; and

superimposing on said enlarged view a viewable marker at a second location spatially corresponding to said first location on said selected first member.

23. The method of claim 22, wherein said first command consists of single-movement input that simultaneously selects said first member and said first location, said single-movement input being selected from the group consisting of:

a mouse point-and-click, a touchscreen stylus point-and-click, a mouse point-and-double-click, and a touchscreen stylus point-and-double-click.

24. The method of claim 22, said thick-slice image array and said enlarged thick-slice image view being displayed on a thick-slice display, further comprising:

receiving cursor movement commands from the user;

moving a cursor position on said thick-slice display responsive to said cursor movement commands;

displaying adjacent to said thick-slice display and concurrently therewith a first planar ultrasound image representing sonographic properties of the breast along a first plane substantially perpendicular to said slab-like subvolume and passing through said cursor position; and

updating in real time said first planar ultrasound image according to said cursor position as said cursor is moved.

25. The method of claim 24, further comprising:

displaying adjacent to said first planar ultrasound image and concurrently therewith a second planar ultrasound image representing sonographic properties of the breast along a second plane different than said first plane, said second plane also being substantially perpendicular to said slab-like subvolume and passing through said cursor position; and

updating in real time said second planar ultrasound image according to said cursor position as said cursor is moved.

26. The method of claim 25, wherein said second plane is orthogonal to said first plane.

27. The method of claim 26, said sonographic properties being acquired by sweeping a linear transducer array across a surface of the breast as the breast is compressed along a first standard x-ray mammogram view plane, wherein (i) each of said slab-like subvolumes is substantially parallel to said first standard x-ray mammogram view plane, (ii) said first plane corresponding to said first planar ultrasound image is substantially parallel to a second standard x-ray mammogram view plane substantially perpendicular to said first standard x-ray mammogram view plane, and (iii) said second plane corresponding to said second planar ultrasound image is substantially orthogonal to said first plane.

28. The method of claim 22, said thick-slice image array and said enlarged thick-slice image view being displayed on a thick-slice display, further comprising:

receiving an inversion command from the user;

responsive to said inversion command, displayed an inverted version of said thick-slice display having an ultrasound brightness convention substantially opposite an ultrasound brightness convention of said thick-slice display.