METHOD AND IMAGE DATA SYSTEM FOR GENERATING A COMBINED CONTRAST MEDIUM AND BLOOD VESSEL REPRESENTATION OF BREAST TISSUE TO BE EXAMINED, COMPUTER PROGRAM PRODUCT AND COMPUTER-READABLE MEDIUM

Abstract

A method for generating a combined contrast medium and blood vessel representation of contrast-enhanced image data of breast tissue to be examined includes capturing first and second contrast-medium-influenced x-ray projection measurement data of the breast tissue with respective differing first and second x-ray energies. First and second image data sets are reconstructed based respectively on the first and second measurement data. A dual-energy image data set is ascertained based on the first and the second image data sets. A blood vessel image is ascertained based on at least one image data set. A blood vessel image is represented together with the dual-energy image data set in a combined contrast medium and blood vessel representation. An image data generating system is also provided.

Claims

1. A method for generating a combined contrast medium and blood vessel representation of breast tissue to be examined, the method comprising the following steps: capturing first contrast-medium-influenced x-ray projection measurement data with a first x-ray energy and second contrast-medium-influenced x-ray projection measurement data with a second x-ray energy differing from the first x-ray energy; reconstructing a first image data set based on the captured first x-ray projection measurement data and a second image data set based on the captured second x-ray projection measurement data; ascertaining a dual-energy image data set based on the first and second image data sets; ascertaining a blood vessel image based on at least one of the first or second image data sets; and representing the blood vessel image together with the dual-energy image data set in a combined contrast medium and blood vessel representation.

2. The method according to claim 1, which further comprises: ascertaining a synthesis image data set, including a tomosynthesis image data set or a synthetic mammogram, based on one of the first or second projection measurement data; and ascertaining the blood vessel image based on the ascertained synthesis image data set.

3. The method according to claim 1, which further comprises ascertaining the blood vessel image from a combination of the first and second image data sets.

4. The method according to claim 1, wherein the dual-energy image data set includes a two-dimensional image data set or a three-dimensional image data set or a dual-energy mammogram.

5. The method according to claim 1, which further comprises obtaining the first and second x-ray projection measurement data by using a CT imaging method.

6. The method according to claim 1, which further comprises ascertaining the blood vessel image by using multi-scaling blood vessel thickening based on the Frangi method, or by using a segmentation of breast vessels in at least one of the first or second image data sets.

7. The method according to claim 6, wherein the segmentation of breast vessels is automatic.

8. The method according to claim 1, which further comprises representing blood vessels in the blood vessel image in dependence on a threshold value, and representing only vessels having an assigned image signal or a signal to noise ratio of the image signal above the threshold value.

9. The method according to claim 8, wherein the threshold value is ascertained from clinical data or is parameterizable.

10. The method according to claim 1, which further comprises carrying out the representation step by at least one of: representing the blood vessel image together with the dual-energy image data set sequentially or simultaneously, or merging the ascertained blood vessel image with the dual-energy image data set to form a superposition image in which structures being highlighted due to contrast medium accumulation and the blood vessel structures are visible.

11. The method according to claim 1, wherein: the first x-ray energy has a first energy value below an energy value of an x-ray absorption edge of a contrast medium used for contrast enhancement, or the second x-ray energy has a second energy value above an energy value of an x-ray absorption edge of the contrast medium used for contrast enhancement, or both energy values of the first and second x-ray energies are above the energy value of the x-ray absorption edge of the contrast medium used for contrast enhancement, and the first energy value is relatively near the energy value of the x-ray absorption edge and the second energy value is relatively remote from the energy value of the x-ray absorption edge, providing contrast-enhanced imaging in an image recording with the first energy, and providing non-contrast-enhanced imaging in an image recording with the second energy.

12. The method according to claim 10, wherein the superposition image has components with a weighting being parameterizable.

13. The method according to claim 10, wherein the merged superposition image is color-coded.

14. The method according to claim 13, which further comprises representing regions being assigned different signal strength threshold values in the blood vessel image in different colors.

15. An image data generating system, comprising: a projection data capturing unit for capturing first contrast-medium-influenced x-ray projection measurement data with a first x-ray energy and second contrast-medium-influenced x-ray projection measurement data with a second x-ray energy differing from the first x-ray energy; an image data generating unit for reconstructing a first image data set of breast tissue to be examined based on the captured first x-ray projection measurement data and a second image data set of the breast tissue to be examined based on the captured second x-ray projection measurement data; and an evaluation unit including: a dual-energy image ascertainment unit configured to ascertain a dual-energy image data set based on the first and the second image data sets, a blood vessel image ascertainment unit configured to ascertain a blood vessel image based on at least one of the first or second image data sets, and a combination image ascertainment unit configured to ascertain a combined contrast medium and blood vessel representation of the blood vessel image and of the dual-energy image data set.

16. A non-transitory computer program product having a computer program, which is loadable directly into a storage unit of an image data generating system according to claim 13, with control sections for carrying out all of the steps of the method according to claim 1 when the computer program is executed in the image data generating system.

17. A non-transitory computer-readable medium, on which control sections which are readable and executable by a computer unit of an image data generating system according to claim 13 are stored to carry out all of the steps of the method according to claim 1 when the control sections are executed by the computer unit of the image data generating system.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0054] FIG. 1 is a block diagram of a conventional mammography system for two-dimensional x-ray recording of a breast;

[0055] FIG. 2 is a block diagram of a conventional tomosynthesis system for three-dimensional x-ray recording of a breast;

[0056] FIG. 3 shows a flowchart, which illustrates a method for generating a combined contrast medium and blood vessel representation of breast tissue to be examined according to one exemplary embodiment of the invention;

[0057] FIG. 4 is a contrast image representation as compared to a combined contrast and blood vessel representation; and

[0058] FIG. 5 is a block diagram, with which an image data generating system according to one exemplary embodiment of the invention is represented.

DETAILED DESCRIPTION OF THE INVENTION

[0059] Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a system 10 for two-dimensional x-ray imaging of the breast, which is also referred to as a mammography system. The mammography system 10 includes an x-ray source 1, from which x-rays 2 are emitted in the direction of a breast 4 in the shape or manner of a fan, i.e. a beam that widens orthogonally to the propagation direction. The breast 4 is placed on an object table 5 and is pressed against the object table 5 by a compression plate 3. In this way, the thickness of the breast in the propagation direction of the x-rays, i.e. in the z-direction, is reduced. The reduction of the thickness of the object that is x-rayed is accompanied by a reduction in the scatter radiation. Some of the x-rays that are incident on the breast 4 are absorbed. The remaining x-rays that are incident on the breast 4 are transmitted and captured by an image sensor 6.

[0060] FIG. 2 shows a conventional tomosynthesis system 20 for three-dimensional image recording of a breast 4. Unlike the 2D mammography system 10 shown in FIG. 1, the tomosynthesis system 20 includes an x-ray source 1 that is rotatable about an object center point M and with which x-ray image recordings can be taken of the breast 4 from different directions or angles. The tomosynthesis system 20 shown in FIG. 2 also includes a compression plate 3 that presses the breast 4 to be examined against an object table 5. The breast 4 to be examined is irradiated by the x-ray source 1 from various angles, so that a multiplicity of individual images of the breast 4 are captured by an x-ray detector 6. A three-dimensional layer image is calculated from the individual images, which permits a layer-wise examination of the tissue of the breast 4.

[0061] FIG. 3 shows a flowchart 300, with which a method for generating a combined contrast medium and blood vessel representation KKG of breast tissue 4 to be examined is illustrated. Prior to the imaging method, a contrast medium is typically injected into the bloodstream of the patient. The contrast medium also reaches the breast through the blood vessels. Blood vessels are located in the breast primarily where lesions are present. In a step 3.I, first x-ray projection measurement data PMD.sub.LE of the breast tissue to be examined are captured with a lower x-ray energy E.sub.L, i.e. with an x-ray energy that is within the range of the absorption edge for x-rays of the contrast medium. In the step 3.I, second x-ray projection data PMD.sub.HE are furthermore captured with a higher x-ray energy E.sub.H, i.e. with an x-ray energy having an energy value which is far above the energy value of the absorption edge for x-rays of the contrast medium.

[0062] In a step 3.II, first and second image data BD.sub.LE, BD.sub.HE are reconstructed from the captured x-ray projection measurement data PMD.sub.LE, PMD.sub.HE. In a step 3.III, a dual-energy image data set DEBD is then ascertained on the basis of the first and second image data BD.sub.LE, BD.sub.HE. For example, image intensities I.sub.DEBD of the dual-energy image data set DEBD are ascertained as follows:

I.sub.DEBD=ln(I.sub.BDHE)−w*ln(I.sub.BDLE),  (1)

[0063] wherein w is the weighting of the image intensities in dependence on the thickness and the type of the tissue to be examined, I.sub.BDLE, I.sub.BDHE include the image intensities of the first and second image data sets BD.sub.LE, BD.sub.HE, and I.sub.DEBD represents the image intensity of the dual-energy image data set. The ascertained dual-energy image DEBD forms the regions of the breast tissue to be examined which are more noticeable due to the contrast medium and in which lesions occur. In order to be able to additionally represent the blood vessel structures of the breast tissue, a blood vessel image GB is generated in a step 3.IV on the basis of one of the two image data sets, in this case the first image data set BD.sub.LE. Imaging of the vessels is effected by a multiscaling vessel thickening based on the Frangi method FM in a step 3.IVa and a subsequent representation of vessels generated in a step 3.IVb, the image intensity I.sub.GB of which is above a predetermined threshold value SW. In a step 3.V, the ascertained image data, i.e. the dual-energy image data set DEBD and the blood vessel image GB, are finally graphically represented simultaneously on a screen and made available for breast cancer diagnosis. In the exemplary embodiment described with regard to in FIG. 3, the image data sets DEBD, GB are superpositioned to form the combined image KKG.

[0064] FIG. 4 illustrates, in a left-hand partial image, the representation of a dual-energy image DEBD that was generated after administration of an iodine contrast medium. In the left-hand partial image, lesions 41, 42 can be seen. Furthermore, a right-hand partial image in FIG. 4 shows an exemplary representation of a merged image KKG from a dual-energy image DEBD, which was generated after administration of an iodine contrast medium, and a blood vessel image GB. In the right-hand image, in addition to the lesions 41, 42, blood vessels 43 can be seen, which cannot be seen in the left-hand partial image.

[0065] FIG. 5 schematically represents an image data generating system 50 according to one exemplary embodiment of the invention. An x-ray projection data recording unit 51 is part of the image data generating system 50. The x-ray projection data recording unit 51 includes functional units, which permit the acquisition of first and second projection measurement data PMD.sub.LE, PMD.sub.HE, which were generated with x-rays with different energy spectra. These functional units can also include, for example, a mammography system 10 or a tomosynthesis system 20, as illustrated in FIG. 1 and FIG. 2, or another imaging system, such as for example a CT system.

[0066] The projection measurement data PMD.sub.LE, PMD.sub.HE that were captured by the x-ray projection data recording unit 51 are transmitted to an image data generating unit 52. The image data generating unit 52 generates first and second image data sets BD.sub.LE, BD.sub.HE on the basis of the captured first and second x-ray projection data PMD.sub.LE, PMD.sub.HE. The generated image data sets are subsequently transmitted to an evaluation unit 53. The evaluation unit 53 includes a contrast image ascertainment unit 53a, which generates a dual-energy contrast image DEBD on the basis of the image data sets BD.sub.LE, BD.sub.HE that were recorded with different x-ray energies. The evaluation unit 53 additionally has a blood vessel image ascertainment unit 53b. The blood vessel image ascertainment unit 53b likewise contains at least one of the first and second image data sets BD.sub.LE, BD.sub.HE, in this case the low-energy image data set BD.sub.LE. The blood vessel image ascertainment unit 53b generates a blood vessel image GB on the basis of the low-energy image data set BD.sub.LE. The evaluation unit 53 additionally includes a combination image ascertainment unit 53c. The combination image ascertainment unit 53c receives the reconstructed dual-energy contrast image data DEBD from the contrast image ascertainment unit 53a and receives the blood vessel image data GB that are generated by the blood vessel image ascertainment unit 53b from the latter. The combination image ascertainment unit 53c generates a combined contrast/blood vessel representation KKG of a breast region to be examined on the basis of the received image data DEBD, GB. The ascertained data for the contrast/blood vessel representation KKG are subsequently transmitted to an image representation unit (not shown) through an output interface 54 of the image data generating system 50. The image representation unit can include, for example, a screen unit on which the combined contrast/blood vessel representation KKG is imaged.

[0067] In closing, it is pointed out once again that the previously described methods and apparatuses are merely preferred exemplary embodiments of the invention and that the invention can be varied by a person skilled in the art without departing from the scope of the invention to the extent to which it is defined by the claims. The method according to the invention was described in connection with the recording of a two-dimensional mammogram and the recording of a three-dimensional tomosynthesis image. However, the invention also includes image representation with the aid of different imaging methods, such as for example computer tomography. In connection with the use of x-rays with high-energy and low-energy, the terms “high” and “low” are to be understood as being relative to the energy of the x-ray absorption edge of a previously administered contrast medium. For the sake of completeness, it is also pointed out that the use of indefinite articles “a” or “an” does not rule out that the features in question can also be presented multiple times. Likewise, the term “unit” does not rule out that the latter includes several components which can, if appropriate, also be distributed in terms of space.