Optical correlator assisted detection of calcifications for breast biopsy

• US 6,421,454 B1
• Filed: 03/08/2000
• Issued: 07/16/2002
• Est. Priority Date: 05/27/1999
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Litton Systems Incorporated
• Inventors: Burke, Thomas M., Carrott, David T.
• Primary Examiner(s): Johns, Andrew W.
• Assistant Examiner(s): NAKHJAVAN, SHERVIN K
• Application Number:
  US09/521,266
• Time in Patent Office: 860 Days
• Field of Search: 382/128, 382/130, 382/131, 382/132, 382/217, 382/218, 382/219, 382/220, 382/276, 382/278, 382/285, 382/287, 382/293, 382/294, 382/295, 382/302, 702/155, 702/159, 702/171, 702/172, 128/922, 378/4, 378/89, 378/21, 378/23, 378/62, 378/63, 378/87, 378/162, 378/165, 359/306, 348/163, 738/610.6, 708/5, 708/813, 708/814, 708/816
• US Class Current: 382/131
• CPC Class Codes: A61B 6/502 for diagnosis of breast, i.e. mammography
• 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 8/0825 for diagnosis of the breast, e.g. mammography
• CPC Class Codes: A61B 8/4416 related to combined acquisition of different diagnostic modalities, e.g. combination of ultrasound and X-ray acquisitions
• CPC Class Codes: G06T 2207/10116 X-ray image
• CPC Class Codes: G06T 2207/10132 Ultrasound image
• CPC Class Codes: G06T 2207/30068 Mammography; Breast
• CPC Class Codes: G06T 7/32 using correlation-based methods

Abstract

Ultrasonographic imaging of small calcifications or similar hard bodies distributed in human breast tissue is enhanced by correlating an ultrasonographic data set with a radiographic image of the same region of interest. A “constellation” or cluster of small calcifications is distinguished from speckle noise by the cross-correlation, which is quite sensitive to the coincidence of a pattern of distributed small targets in both the ultrasonographic and radiographic images, notwithstanding the presence of random noise. An optical correlator is preferably used to perform high speed cross-correlations. The three-dimensional position of an individual calcification is preferably found by projecting from an identified point in the radiographic image, along a projection vector, to a voxel with extreme density in the ultrasonographic volumetric data set. Multiple projection vector orientations are tested for image correlation, to accomodate any probable skew between the ultrasonographic and radiographic projections.

Claims

1. A method of imaging small objects such as calcifications in a bodily tissue, comprising the steps of:

providing radiographic image data from an identified region of interest (ROI) of the tissue using a first imaging unit;

providing three-dimensional ultrasonographic image data corresponding to substantially the same ROI either before or after said radiographic image data is provided and using a second imaging unit independent of said first imaging unit such that said ROI need not be identically positioned for both radiographic and ultrasonographic image acquisition; and

generating an image of the objects based upon a coincidence of data in the radiographic and the ultrasonographic imagery, said coincidence determined by cross-correlation of (a) the radiographic image data, and (b) a two-dimensional reduction of the three-dimensional ultrasonographic image data.

2. The method of claim 1, wherein said two-dimensional reduction comprises multiple pixels, and a data value at a pixel is computed by taking an extremum data value from data associated with positions along a projection vector which intersects said pixel.

3. The method of claim 1, wherein said two-dimensional reduction comprises multiple pixels, and a data value at a pixel is computed by taking a sum of data associated with positions along a projection vector which intersects said pixel.

4. The method of claim 1, further comprising the step of:

finding the position of an object by projecting back along the projection vector from a target image in the radiographic image to an extremum data value along said vector in the ultrasonographic data.

5. The method of claim 1, further comprising:

displaying a visual representation of the ROI on a display; and

enhancing the visibility of a target object within the display based upon the congruence of (a) an assumed projection of the target object and (b) a radiographic indication of a dense object.

6. The method of claim 5, wherein the assumed projection of the target object is found by searching for a geometric relationship between the radiographic data and the ultrasonographic data which cross-correlation value in a predetermined range.

7. A method of imaging small objects such as calcifications in a bodily tissue, comprising the steps of:

providing radiographic image data from an identified region of interest (ROI) of the tissue;

providing three-dimensional ultrasonographic image data corresponding to substantially the same ROI; and

generating an image of the objects based upon a coincidence of data in the radiographic and the ultrasonographic imagery, said coincidence determined by cross-correlation of (a) the radiographic image data, and (b) a two-dimensional reduction of the three-dimensional ultrasonographic image data, wherein the cross-correlation is performed by an optical correlator.

8. A method of imaging small objects such as calcifications in a bodily tissue, comprising the steps of:

providing radiographic image data from an identified region of interest (ROI) of the tissue;

providing three-dimensional ultrasonographic image data corresponding to substantially the same ROI; and

generating an image of the objects based upon a coincidence of data in the radiographic and the ultrasonographic imagery, said coincidence determined by cross-correlation of (a) the radiographic image data, and (b) a two-dimensional reduction of the three-dimensional ultrasonographic image data, wherein the cross-correlation comprises computing an image wherein the image value at each position x,y approximates the cross-correlation function H_y defined by;

9. A method of locating one or more small, radiographically dense objects within a subject body, comprising the steps of:

providing a radiographic image of an area of interest (ROI) including the object using a first imaging unit;

deriving an image from three-dimensional ultrasonographic volumetric data either before or after said radiographic image data is provided and using a second imaging unit independent of said first imaging unit such that said ROI need not be identically positioned for both radiographic and ultrasonographic image acquisition;

cross-correlating the derived image with the radiographic image;

identifying the target object based on a predetermined degree of correlation between the images; and

displaying a visual interpretation derived from the ultrasonographic volume data set, in which a probable target object has its visibility enhanced based on a coincidence of image data in the radiographic and ultrasonographic images.

10. The method of claim 9, wherein the step of providing a radiographic image comprises:

scanning a portion of a radiographic film with a digitizing scanner, and

storing the resulting data as radiographic image data.

11. A method of locating one or more small, radiographically dense objects within a subject body, comprising the steps of:

providing a radiographic image of an area of interest (ROI) including the object;

deriving an image from three-dimensional ultrasonographic volumetric data;

cross-correlating the derived image with the radiographic image using an optical correlator;

identifying the target object based on a predetermined degree of correlation between the images; and

displaying a visual interpretation derived from the ultrasonographic volume data set, in which a probable target object has its visibility enhanced based on a coincidence of image data in the radiographic and ultrasonographic images.

12. A method of locating one or more small, radiographically dense objects within a subject body, comprising the steps of:

providing a radiographic image of an area of interest (ROI) including the object;

deriving an image from three-dimensional ultrasonographic volumetric data;

cross-correlating the derived image with the radiographic image, wherein the cross-correlating step comprises computing an image wherein the image value at each position x,y approximates the function H, defined by;

13. A method for guiding a biopsy instrument to sample a calcification or other small sample from a human body, comprising the steps of:

providing radiographic image data regarding of a region of interest (ROI) from the human body using a first imaging unit;

providing ultrasonographic image data from substantially the same ROI either before or after said radiographic image data is provided and using a scanning ultrasonographic apparatus independent of said first imaging unit such that said ROI need not be identically positioned for both radiographic and ultrasonographic image acquisition;

locating a calcification in relation to the ultrasonographic apparatus, by cross-correlating said radiographic and said ultrasonographic image data to register the image data; and

guiding the biopsy instrument to the calcification based upon its determined location.

14. A method for guiding a biopsy instrument to sample a calcification or other small sample from a human body, comprising the steps of:

providing radiographic image data regarding of a region of interest from the human body;

providing ultrasonographic image data from substantially the same region, by scanning ultrasonographic apparatus;

locating a calcification in relation to the ultrasonographic apparatus, by cross-correlating said radiographic and said ultrasonographic image data to register the image data, said cross-correlating step performed by an optical correlator; and

guiding the biopsy instrument to the calcification based upon its determined location.

15. A method for guiding a biopsy instrument to sample a calcification or other small sample from a human body, comprising the steps of:

providing radiographic image data regarding of a region of interest from the human body;

providing ultrasonographic image data from substantially the same region, by scanning ultrasonographic apparatus;

locating a calcification in relation to the ultrasonographic apparatus, by cross-correlating said radiographic and said ultrasonographic image data to register the image data, said cross correlation step comprising computing an image wherein the image value at each position x,y approximates the function H, defined by;

16. A method for guiding a biopsy instrument to sample a calcification or other small sample from a human body, comprising the steps of:

providing radiographic image data regarding of a region of interest from the human body;

providing ultrasonographic image data from substantially the same region, by scanning ultrasonographic apparatus;

locating a calcification in relation to the ultrasonographic apparatus, by cross-correlating said radio-graphic and said ultrasonographic image data to register the image data, said correlation calculated in a frequency domain representation; and

guiding the biopsy instrument to the calcification based upon its determined location.

17. A system for enhancing imagery of bodily tissues by relating ultrasonographic and radiographic images, comprising:

an image processor, programmed to;

(a) receive said ultrasonographic and said radiographic images, (b) process said images to derive processed ultrasonographic and radiographic images, and (c) control an optical correlator to compute cross-correlation images from said processed images; and

an optical correlator coupled to said image processor and arranged to correlate said processed images and to output to said image processor a cross correlation image which is indicative of the correlation between the processed images.

18. The system of claim 17, wherein the image processor is programmed to relate either the radiographic image or the ultrasonographic image to a spatial coordinate system, and to transform at least a portion of the other of the images to the spatial coordinate system.

19. The system of claim 17, wherein the image processor is further programmed to locate at least one of multiple small targets distributed in the bodily tissue, by calculating a three-dimensional configuration of said targets consistent with both the ultrasonographic and the radiographic image data.

20. The system of claim 17, further comprising an ultrasonographic imaging system, arranged to communicate ultrasonographic image data to said image processor, for imaging a bodily tissue ultrasonographically.

21. The system of claim 17, further comprising a high resolution film scanner, arranged to scan and digitize radiographic film of a subject bodily tissue and to communicate data to said image processor for analysis.

22. The system of claim 17, wherein said image processor communicates with a data network to receive image data regarding a subject bodily tissue.

23. The system of claim 17, wherein said image processor communicates with a biopsy apparatus, to aid in guiding a biopsy instrument toward a target.

24. The system of claim 17, further comprising:

a biopsy apparatus, in communication with said image processor to aid in guiding a biopsy instrument toward a target.