Angiographic examination method for overlaying virtual vascular projection images with medical instrument projection images based on projection matrix

1. An angiographic examination method for depicting a target region inside a patient with a vascular system as an examination object using an angiography system comprising an X-ray emitter and an X-ray image detector that are attached to ends of a C-arm, a patient positioning couch with a tabletop on which the patient is positioned, a processor, an image system, and a monitor, the angiographic examination method comprising:

capturing a volume data set of the target region with the examination object;

registering the volume data set to the C-arm;

extracting information about an assumed course of the examination object in the volume data set inside the target region;

generating at least one two-dimensional (2D) projection image of a medical instrument inserted in the target region;

generating a 2D overlay image, the generating of the 2D overlay image comprising 2D/3D merging of the at least one 2D projection image and of the registered volume data set;

detecting the medical instrument inserted in the target region in the 2D overlay image with a first projection matrix;

generating a virtual 2D projection of the medical instrument using a virtual projection matrix, wherein the virtual projection matrix is based on the first projection matrix;

reconstructing the medical instrument in three dimensions, in which a three-dimensional (3D) position of the medical instrument is determined from the virtual 2D projection and the at least one 2D projection image of the medical instrument; and

overlaying the virtual 2D projection and the at least one 2D projection image of the medical instrument, and distorting a center line of at least a part of the at least one 2D projection image by a displacement such that a current course and the assumed course of the vessels are congruent.

2. The angiographic examination method of claim 1 , wherein generating the virtual 2D projection of the medical instrument comprises:

generating a virtual projection matrix, the generating of the virtual projection matrix comprising rotating the first projection matrix by an angle about an axis through the patient;

generating the virtual 2D projection of the medical instrument using the virtual projection matrix; and

approximating the medical instrument in the virtual 2D projection of the medical instrument, the approximating comprising estimating the position of the medical instrument from the virtual 2D projection of the medical instrument.

3. The angiographic examination method of claim 1 , wherein capturing the volume data set comprises capturing a 3-D volume based on a previously performed computed tomography (CT) angiography or a C-arm CT recorded during an intervention.

4. The angiographic examination method of claim 1 , wherein the information about the assumed course of the examination object is obtained using a 3D segmentation over the course of the vessels.

5. The angiographic examination method of claim 4 , wherein the information is center lines of the vessels, a course of vascular lumina, or the center lines of the vessels and the course of vascular lumina.

6. The angiographic examination method of claim 1 , wherein detecting the medical instrument comprises generating a two-dimensional polygon line that corresponds to the position of the instrument in the at least one 2D projection image.

7. The angiographic examination method of claim 2 , wherein the angle is 90°.

8. The angiographic examination method of claim 2 , wherein during the approximating of the medical instrument, a smoothing interpolation is used to determine the position of the medical instrument, which depending on a level of inflexibility of the medical instrument, is a linear, quadratic or spline interpolation.

9. The angiographic examination method of claim 1 , wherein reconstructing the medical instrument in three dimensions comprises a triangulation from the virtual 2D projection and the at least one 2D projection image of the medical instrument.

10. The angiographic examination method of claim 1 , wherein the overlaying and distorting comprises positioning a part of the vessels corresponding to the course of the vessels so as to coincide with a relevant part of the inserted medical instrument for which 3D positions are available, and adjusting the overlay of the virtual 2D projection and the at least one 2D projection image of the medical instrument depending on the position and a penetration depth of the medical instrument.

11. The angiographic examination method of claim 2 , wherein capturing the volume data set comprises capturing a 3-D volume based on a previously performed computed tomography (CT) angiography or a C-arm CT recorded during an intervention.

12. The angiographic examination method of claim 11 , wherein the information about the assumed course of the examination object is obtained using a 3D segmentation over the course of the vessels.

13. The angiographic examination method of claim 12 , wherein the information is center lines of the vessels, a course of vascular lumina, or the center lines of the vessels and the course of vascular lumina.

14. The angiographic examination method of claim 13 , wherein detecting the medical instrument comprises generating a two-dimensional polygon line that corresponds to the position of the instrument in the at least one 2D projection image.

15. The angiographic examination method of claim 14 , wherein the angle is 90°.

16. The angiographic examination method of claim 15 , wherein during the approximating of the medical instrument, a smoothing interpolation is used to determine the position of the medical instrument, which depending on a level of inflexibility of the medical instrument, is a linear, quadratic or spline interpolation.

17. The angiographic examination method of claim 7 , wherein reconstructing the medical instrument in three dimensions comprises a triangulation from the virtual 2D projection and the at least one 2D projection image of the medical instrument.

18. The angiographic examination method of claim 8 , wherein reconstructing the medical instrument in three dimensions comprises a triangulation from the virtual 2D projection and the at least one 2D projection image of the medical instrument.

19. The angiographic examination method of claim 7 , wherein the overlaying and distorting comprises positioning a part of the vessels corresponding to the course of the vessels so as to coincide with a relevant part of the inserted medical instrument for which 3D positions are available, and adjusting the overlay of the virtual 2D projection and the at least one 2D projection image of the medical instrument depending on the position and a penetration depth of the medical instrument.

20. The angiographic examination method of claim 8 , wherein the overlaying and distorting comprises positioning a part of the vessels corresponding to the course of the vessels so as to coincide with a relevant part of the inserted medical instrument for which 3D positions are available, and adjusting the overlay of the virtual 2D projection and the at least one 2D projection image of the medical instrument depending on the position and a penetration depth of the medical instrument.