Registration of medical images
The invention relates to a method and an image processing device ( 50 ) for the registration of two images (I 1 , I 2 ) that may for example be provided by a CT scanner ( 10 ) and/or an MRI scanner ( 20 ). According to one embodiment of the invention, the images are first globally registered (GR) with a given registration algorithm using a first parameter vector (p). A user may then select a region of interest ROI, and a plurality of local registrations (LR 1 , . . . LRs, . . . LRn) are calculated for this ROI using the same registration algorithm but different parameter vectors (p, p, . . . p). The results of the local registrations (LR 1 , . . . LRs, . . . LRn) are displayed and the user can select the best local registration(s). In a final step, the selected local registration(s) (LRs) and the global registration (GR) may be merged. Additionally or alternatively, a parameter vector for a local registration in the ROI may be determined by an automatic analysis of the ROI.
1. An image processing device that registers at least two images of an object, comprising:
a processor configured:
to execute a global registration of the at least images using a given registration algorithm with a first parameter vector;
to select of a region of interest (ROI) in the images; and
to execute at least one local registration of the at least images within the selected ROI using the given registration algorithm with a different parameter vector;
wherein a parameter vector is determined for at least one local registration based on an automatic analysis of the ROI which comprises the evaluation of:
intensity ranges,
intensity histograms,
image edges,
edge histograms,
entropy measurements,
intensity range of residuum,
and/or anatomical position.
2. A medical imaging apparatus, comprising:
at least one imaging scanner for generating images of an object;
the image processing device according to claim 1 for the registration of images provided by the imaging scanner.
3. The medical imaging apparatus of claim 2 ,
wherein at least two local registrations are executed with different parameter vectors.
4. The medical imaging apparatus of claim 2 ,
wherein the automatic analysis of the ROI comprises the evaluation of:
intensity ranges with respect to an anatomical content that indicates a preferred parameter vector,
image edges with respect to edges of smaller strength that require a parameter vector to enhance their strength,
intensity range of residuum with respect to the occurrence of pairs of positive and negative intensities,
and/or anatomical position with respect to the anatomical position of the ROI indicating an organ-specific or bone-specific parameter vector.
5. The medical imaging apparatus of claim 2 ,
wherein the ROI is automatically selected.
6. The medical imaging apparatus of claim 2 ,
wherein the global registration and at least one of the local registrations are merged.
7. The medical imaging apparatus of claim 2 ,
wherein the global registration and the local registration are non-rigid registrations.
8. The medical imaging apparatus of claim 2 ,
wherein the parameter vectors comprise at least one parameter selected from the group consisting of a material property, a weighting factor, a number of iterations, and an image resolution.
9. The medical imaging apparatus of claim 2 ,
wherein the images are generated by one of an X ray device, a CT scanner, an MR scanner, a PET scanner, a SPECT scanner, or an ultrasound device.
10. The image processing device of claim 1
wherein at least two local registrations are executed with different parameter vectors.
11. The image processing device of claim 10 ,
wherein the results of said local registrations are displayed and that a user can select at least one of the displayed local registrations.
12. The image processing device of claim 11 ,
wherein the selected local registration is refined.
13. The image processing device of claim 10 ,
wherein user's selections are evaluated with respect to the user's preferences.
14. The image processing device of claim 1 ,
wherein the automatic analysis of the ROI comprises the evaluation of:
intensity ranges with respect to an anatomical content that indicates a preferred parameter vector,
image edges with respect to edges of smaller strength that require a parameter vector to enhance their strength,
intensity range of residuum with respect to the occurrence of pairs of positive and negative intensities,
and/or anatomical position with respect to the anatomical position of the ROI indicating an organ-specific or bone-specific parameter vector.
15. The image processing device of claim 1 ,
wherein the ROI is automatically selected.
16. The image processing device of claim 1 ,
wherein the global registration and at least one of the local registrations are merged.
17. The image processing device of claim 1 ,
wherein the global registration and the local registration are non-rigid registrations.
18. The image processing device of claim 1 ,
wherein the parameter vectors comprise at least one parameter selected from the group consisting of a material property, a weighting factor, a number of iterations, and an image resolution.
19. The image processing device of claim 1 ,
wherein the images are generated by one of an X ray device, a CT scanner, an MRI scanner, a PET scanner, a SPECT scanner, or an ultrasound device.
20. A method for a registration of at least two images of an object, said method comprising:
a) a “global registration” of the at least two images using a given registration algorithm with a first parameter vector;
b) a selection of a region of interest (ROI) in the at least two images;
c) at least one “local registration” of the at least two images within the selected ROI using the given registration algorithm with a different parameter vector;
wherein a parameter vector is determined for at least one local registration based on an automatic analysis of the ROI which comprises the evaluation of:
intensity ranges,
intensity histograms,
image edges,
edge histograms,
entropy measurements,
intensity range of residuum,
and/or anatomical position.
21. The method of claim 20 ,
wherein step c) is repeated at least once.
22. The method of claim 20 ,
wherein at least two local registrations are executed with different parameter vectors.
23. The method of claim 20 ,
wherein the automatic analysis of the ROI comprises the evaluation of:
intensity ranges with respect to an anatomical content that indicates a preferred parameter vector,
image edges with respect to edges of smaller strength that require a parameter vector to enhance their strength,
intensity range of residuum with respect to the occurrence of pairs of positive and negative intensities,
and/or anatomical position with respect to the anatomical position of the ROI indicating an organ-specific or bone-specific parameter vector.
24. The method of claim 20 ,
wherein the ROI is automatically selected.
25. The method of claim 20 ,
wherein the global registration and at least one of the local registrations are merged.
26. The method of claim 20 ,
wherein the global registration and the local registration are non-rigid registrations.
27. The method of claim 20 ,
wherein the parameter vectors comprise at least one parameter selected from the group consisting of a material property, a weighting factor, a number of iterations, and an image resolution.
28. The method of claim 20 ,
wherein the images are generated by one of an X ray device, a CT scanner, an MR scanner, a PET scanner, a SPECT scanner, or an ultrasound device.