Registration of fluoroscopic images of the chest and corresponding 3D image data based on the ribs and spine
View Patent ↗The present invention is a method to register 3D image data with fluoroscopic images of the chest of a patient. The ribs and spine, which are visible in the fluoroscopic images, are analyzed and a rib signature or cost map is generated. The rib signature or cost map is matched to corresponding structures of the 3D image data of the patient. Registration is evaluated by computing a difference between the fluoroscopic image and a virtual fluoroscopic projected image of the 3D data. Related systems are also described.
1. A computer implemented method to assist with registering 3D data with fluoroscopic images of a thorax of a patient comprising the steps of:
receiving the fluoroscopic images of the thorax including an anatomical structure which is visible under fluoroscopy;
approximating a candidate location of the anatomical structure based on the fluoroscopic images;
receiving a 3D data set of the anatomical structure in the thorax; and
registering the 3D data set with the fluoroscopic images based on the approximating step; and
wherein the registering step employs a routine on a computer to automatically calculate an optimal transformation that optimizes the alignment cost between the candidate location of the anatomical structure with the anatomical structure of the 3D data set.
2. The method of claim 1 , wherein the anatomical structure is one structure selected from the group comprising a rib and spine.
3. The method of claim 1 , wherein the 3D data set is at least one data selected from the group comprising image data and model data.
4. The method of claim 1 , further comprising estimating a motion between the candidate location of the anatomical structure from the approximating step, and the 3D-projected location of the anatomical structure from the 3D data set.
5. The method of claim 1 , further comprising, at least in part, manually selecting the candidate location of the anatomical structure in the fluoroscopic image data set.
6. The method of claim 1 , wherein the approximating step comprises automatically determining a probability map of rib and spine locations.
7. The method of claim 1 , further comprising computing centerlines of the anatomical structure from the 3D data set, and performing the registration step based on the centerlines.
8. A computer implemented method for evaluating a completed registration between fluoro images of the thorax and a 3D-based fluoro projection image computed from a 3D data set, the method comprising:
estimating a displacement motion between the fluoro images and the 3D-based fluoro projection image;
computing on a processor a final displacement error based on the displacement motion from the estimating step; and
wherein the displacement motion comprises a plurality of displacement values computed on a processor between a weighted anatomical structure computed from the fluoro images and the 3D-based fluoro projection, and the final displacement error is based on weighting at least one displacement value more than another.
9. The method of claim 8 , wherein the step of estimating the displacement motion is performed with a block matching algorithm.
10. The method of claim 9 , wherein higher weighting is assigned to displacement values associated with a boney structure.
11. The method of claim 10 , wherein the boney structure comprises ribs.
12. The method of claim 11 , wherein the boney structure excludes the diaphragm.
13. The method of claim 8 , wherein, prior to computing the displacement error, a rib-probability map is generated based on the fluoro images of the thorax and approximating a candidate location of the ribs.
14. The method of claim 8 , comprising repeating or adjusting the completed registration based on the final displacement error.
15. The method of claim 8 , further comprising detecting patient motion post-registration by:
receiving current fluoroscopic images;
computing a current 2D displacement motion between the current fluoroscopic images and 3D-based fluoro projection images.
16. The method of claim 15 , further comprising indicating whether the patient has moved by computing whether the current 2D displacement motion exceeds an acceptable range.
17. A computer implemented fluoroscopy assistance system to assist with registering 3D data with fluoroscopic images of a thorax of a patient comprising a computer processor programmed to:
receive a fluoroscopic image data set of the thorax including an anatomical structure which is visible under fluoroscopy;
receive a 3D data set of the thorax including the anatomical structure;
computing on a processor a candidate signature representing the anatomical structure based on the fluoroscopic image data and a virtual signature based on the 3D data set; and
register the 3D data set with the fluoroscopic image data set based on the at least one of the candidate signature and the virtual signature;
wherein the registering step employs a routine on a computer to automatically calculate an optimal transformation that optimizes the alignment cost between the candidate signature of the anatomical structure with the virtual signature of the 3D data set.
18. The system of claim 17 , wherein the anatomical structure is one structure selected from the group comprising a rib and spine.
19. The system of claim 18 , wherein the virtual signature comprises centerlines of ribs.
20. The system of claim 19 , comprising computing the candidate signature and the virtual signature wherein the candidate signature is based on determining a probability map of rib and spine locations.