Non-invasive method for using 2D angiographic images for radiosurgical target definition

1. A method, comprising:

acquiring a plurality of two-dimensional (2D) angiographic images with two or more orientations of an angiographic imaging system having a three-dimensional (3D) object space, wherein each of the plurality of 2D angiographic images includes a projection of a plurality of non-invasive fiducial markers having a known 3D configuration, and wherein an imaging geometry of each of the two or more orientations of the angiographic imaging system is unknown with respect to a 3D imaging system having a 3D scan volume prior to acquiring the plurality of 2D angiographic images;

determining the imaging geometry of each of the two or more orientations of the angiographic imaging system based on the projection of the plurality of non-invasive fiducial markers in each of the plurality of 2D angiographic images and the known 3D configuration of the plurality of non-invasive fiducial markers;

generating, after acquiring the plurality of 2D angiographic images, a plurality of digitally reconstructed radiograph (DRR) sets from the 3D scan volume based on the determined imaging geometry of the two or more orientations of the angiographic imaging system; and

comparing, by one or more processors, selected 2D angiographic images of the plurality of 2D angiographic images to selected DRRs of the plurality of DRR sets to register the 3D object space of the angiographic imaging system to the 3D scan volume of the 3D imaging system.

2. The method of claim 1 , wherein the plurality of non-invasive fiducial markers is arrayed on a non-invasive calibration device of known configuration, wherein the calibration device has a fixed location relative to a patient's head.

3. The method of claim 1 , wherein the plurality of non-invasive fiducial markers is temporarily attached to a patient's head, the method further comprising

determining the 3D configuration of the plurality of non-invasive fiducial markers by,

acquiring a calibrated 3D image of the patient, and

measuring the configuration of the plurality of non-invasive fiducial markers in the calibrated 3D image.

4. The method of claim 1 , wherein the plurality of non-invasive fiducial markers comprise tracking objects temporarily attached to a patient's head, and wherein a configuration of the tracking objects is determined by a 3D tracking system.

5. The method of claim 1 , further comprising:

identifying contours of a target vasculature in one or more of the plurality of 2D angiographic images in each of the two or more orientations;

back-projecting the contours of the target vasculature, through the imaging geometry of the two or more orientations, to a 3D object space; and

rendering a volume of the target vasculature in the 3D object space.

6. The method of claim 1 further comprising:

identifying contours of a target vasculature in the 3D scan volume;

projecting the contours of the target vasculature, through an imaging geometry of one or more orientations of the angiographic imaging system; and

displaying the projections of the target vasculature in one or more 2D angiographic images.

7. A system, comprising:

a storage device; and

one or more processors operatively coupled with the storage device, the one or more processors to:

receive data comprising a plurality of two-dimensional (2D) angiographic images of an anatomical region in two or more orientations of an angiographic imaging system having a three-dimensional (3D) object space, wherein each of the plurality of 2D angiographic images includes a projection of a plurality of non-invasive fiducial markers having a known 3D configuration, and wherein an imaging geometry of each of the two or more orientations of the angiographic imaging system is unknown with respect to a 3D imaging system having a 3D scan volume prior to receiving the data comprising the plurality of 2D angiographic images;

determining the imaging geometry of each of the two or more orientations of the angiographic imaging system based on the projection of the plurality of non-invasive fiducial markers in each of the plurality of 2D angiographic images and the known 3D configuration of the plurality of non-invasive fiducial markers;

generating, after receiving the data comprising the plurality of 2D angiographic images, a plurality of digitally reconstructed radiograph (DRR) sets from the 3D scan volume based on the determined imaging geometry of the two or more orientations of the angiographic imaging system; and

comparing data of selected 2D angiographic images of the plurality of 2D angiographic images to data of selected DRRs of the plurality of DRR sets to register the 3D object space of the angiographic imaging system to the 3D scan volume of the 3D imaging system.

8. The system of claim 7 , wherein the one or more processors are further to:

identify contours of a target vasculature in one or more of the plurality of 2D angiographic images in each of the two or more orientations;

back-project the contours of the target vasculature, through the imaging geometry of the two or more orientations, to a 3D object space; and

render a volume of the target vasculature in the 3D object space.

9. The system of claim 7 , wherein to register the 3D object space of the angiographic imaging system to the 3D scan volume of the 3D imaging system, the one or more processors are to:

find a transformation between the 3D scan volume and the 3D object space that maximizes a similarity measure between the selected DRRs and the selected 2D angiographic images.

10. The system of claim 9 , wherein the one or more processors are further to identify contours of a target vasculature in one or more of the plurality of 2D angiographic images, wherein the target vasculature comprises a nidus of an arteriovenous malformation (AVM), wherein the plurality of 2D angiographic images comprises one or more time-series of angiographic images recording progress of a contrast agent from injection through infusion of the nidus, and wherein the selected 2D angiographic images include images without contrast agent and images with contrast agent.

11. The system of claim 8 , wherein the one or more processors are further to identify contours of a target vasculature in one or more of the plurality of 2D angiographic images, wherein the target vasculature comprises a nidus of an arteriovenous malformation (AVM), wherein the plurality of 2D angiographic images comprises one or more time-series of angiographic images recording progress of a contrast agent from injection through infusion of the nidus, and wherein the selected 2D angiographic images include images without contrast agent.

12. The system of claim 9 , wherein the one or more processors are further to identify contours of a target vasculature in one or more of the plurality of 2D angiographic images, wherein the target vasculature comprises a nidus of an arteriovenous malformation (AVM), wherein the plurality of 2D angiographic images comprises one or more time-series of angiographic images recording progress of a contrast agent from injection through infusion of the nidus, and wherein the selected 2D angiographic images include images with contrast agent.

13. The system of claim 9 , wherein the similarity measure comprises an image intensity similarity measure, and wherein to find the transformation between the 3D scan volume and the 3D object space, the one or more processors are configured to apply a six-parameter registration algorithm to maximize the similarity measure.

14. The system of claim 9 , wherein the one or more processors are further to:

identify contours of a target vasculature in one or more of the plurality of 2D angiographic images;

fuse the 3D object space with the 3D scan volume using the transformation between the 3D scan volume and the 3D object space; and

generate contours of the target vasculature from a volume of the target vasculature in the 3D object space.

15. The system of claim 7 , wherein the one or more processors are further to:

identify contours of a target vasculature in the 3D scan volume;

project the contours of the target vasculature, through an imaging geometry of one or more orientations of the angiographic imaging system; and

display the projections of the target vasculature in one or more 2D angiographic images.

16. A non-transitory machine-readable medium including data that, when executed by one or more processors, cause the one or more processors to perform operations comprising:

acquiring a plurality of two-dimensional (2D) angiographic images with two or more orientations of an angiographic imaging system having a three-dimensional (3D) object space, wherein each of the plurality of 2D angiographic images includes a projection of a plurality of non-invasive fiducial markers having a known 3D configuration, and wherein an imaging geometry of each of the two or more orientations of the angiographic imaging system is unknown with respect to a 3D imaging system having a 3D scan volume prior to acquiring the plurality of 2D angiographic images;

determining the imaging geometry of each of the two or more orientations of the angiographic imaging system based on the projection of the plurality of non-invasive fiducial markers in each of the plurality of 2D angiographic images and the known 3D configuration of the plurality of non-invasive fiducial markers;

generating, after acquiring the plurality of 2D angiographic images, a plurality of digitally reconstructed radiograph (DRR) sets from the 3D scan volume based on the determined imaging geometry of the two or more orientations of the angiographic imaging system; and

comparing selected 2D angiographic images of the plurality of 2D angiographic images to selected DRRs of the plurality of DRR sets to register the 3D object space of the angiographic imaging system to the 3D scan volume of the 3D imaging system.

17. The non-transitory machine-readable of claim 16 , wherein the plurality of non-invasive fiducial markers is temporarily attached to a patient's head, wherein the machine-readable medium further includes data that cause the one or more processors to perform operations comprising:

determining the 3D configuration of the plurality of non-invasive fiducial markers by,

acquiring a calibrated 3D image of the patient, and

measuring the configuration of the plurality of non-invasive fiducial markers in the calibrated 3D image.

18. The non-transitory machine-readable of claim 16 , wherein the machine-readable medium further includes data that cause the one or more processors to perform operations comprising:

identifying contours of a target vasculature in the 3D scan volume;

projecting the contours of the target vasculature, through an imaging geometry of one or more orientations of the angiographic imaging system; and

displaying the projections of the target vasculature in one or more 2D angiographic images.