Cut-surface display of tubular structures

1. A method for visualizing a tubular object of interest from a set of volumetric data comprising:

determining a viewing direction for the tubular object;

selecting a constraint subset of the tubular object within a set of volumetric data;

defining a cut-surface through the volumetric data, the cut-surface comprising a three-dimensional surface within the volumetric data and including the constraint subset of the tubular object within the volumetric data such that the cut-surface intersects the constraint subset of the tubular object; and

rendering an image based upon the determined viewing direction and the volumetric data of the tubular object along the intersection of the volumetric data and the defined cut-surface.

2. The method of claim 1 , wherein the volumetric data comprise CT or MRI data.

3. The method of claim 1 , wherein the determining the viewing direction comprises:

implementing a predefined setting;

receiving a selection of a viewing direction; or

calculating an optimal viewing direction.

4. The method of claim 3 , wherein receiving a selection of a viewing direction comprises providing a rotatable two-dimensional visualization of the volumetric data and receiving a selected orientation based on a rotated position of the rotatable two-dimensional visualization.

5. The method of claim 4 , wherein the rotatable two-dimensional visualization comprises an oblique MPR, a 2D maximum intensity projection (MIP) or a 2D minimum intensity projection (MinIP).

6. The method of claim 3 , wherein receiving a selection of a viewing direction comprises providing a rotatable three-dimensional visualization of the volumetric data and receiving a selected orientation based on a rotated position of the rotatable three-dimensional visualization.

7. The method of claim 6 , wherein the rotatable three-dimensional visualization comprises a maximum intensity projection (MIP) or a minimum intensity projection (MinIP).

8. The method of claim 3 , further comprising receiving information representative of the orientation of an external medical device and/or planning system and wherein determining the viewing direction is based upon the received information.

9. The method of claim 3 , wherein calculating an optimal viewing direction comprises:

calculating a weighted average of a plurality of bifurcation normal vectors, each of the plurality of bifurcation normal vectors being associated with a different identified bifurcation in the tubular object.

10. The method of claim 3 , wherein calculating an optimal viewing direction comprises performing a principal component analysis of the tubular object in the volumetric data.

11. The method of claim 1 , wherein identifying constraints in the volumetric data comprises selecting a plurality of points within the tubular object; and wherein defining a cut-surface throughout the volumetric data comprises interpolating between and/or extrapolating from the selected plurality of points.

12. The method of claim 11 , wherein the selected plurality of points within the tubular object correspond to selected one or more branches of the tubular object.

13. The method of claim 12 , wherein selecting one or more branches comprises:

prioritizing the branches of the tubular object; and

selecting branches in descending order of priority and excluding branches having a centerline that passes in front of or behind a centerline of a branch that has been previously selected.

14. The method of claim 13 , further comprising assigning a score to each branch, the score corresponding to the sum of its length and the length of its descendant branches when projected onto a plane normal to the determined viewing direction, and wherein branches are prioritized according to the assigned score.

15. The method of claim 13 , wherein branches are prioritized according to distance from the branch to one or more locations of interest in the volumetric data.

16. The method of claim 15 , wherein branches are prioritized from lowest distance to highest distance.

17. The method of claim 13 , further comprising:

comparing the volumetric data of the tubular object to volumetric data of the tubular object taken at a previous time; and

determining, for a plurality of regions in the volumetric data, an amount of change in the volumetric data from the previous time; and wherein

branches are prioritized according to an amount of change in the volumetric data from the previous time.

18. The method of claim 1 , further comprising:

determining, for a plurality of regions in the rendered image, an amount of distortion present in the image due to the cut-surface; and

generating a display showing the amount of distortion present at a plurality of locations within the rendered image.

19. The method of claim 1 , further comprising:

changing the viewing direction of the tubular object to an updated viewing direction;

updating the cut-surface through the volumetric data based on the constraint subset and the updated viewing direction; and

rendering an updated image based upon the updated viewing direction and the volumetric data of the tubular object along the intersection of the volumetric data and the updated cut-surface.

20. A method for visualizing a tubular object of interest from a set of volumetric data comprising:

identifying a plurality of bifurcations in the tubular object;

assigning a weighting factor to each of the identified bifurcations;

determining a bifurcation normal vector associated with each of the plurality of bifurcations;

determining a weighted average of the bifurcation normal vectors based on the weighting factors and determined bifurcation normal vectors for each of the plurality of identified bifurcations; and

rendering an image of the volumetric data from a perspective parallel to the weighted average of the bifurcation normal vectors.

21. The method of claim 20 , wherein the weighting factor associated with a given bifurcation is related to the number of bifurcations preceding the given bifurcation, and wherein bifurcations with fewer preceding bifurcations are given a stronger weight than bifurcations with more preceding bifurcations.

22. The method of claim 20 , further comprising identifying one or more points of interest within the volume, and wherein the weighting factor associated with a given bifurcations is based on a distance metric between the given bifurcation and the one or more of the points of interest.

23. The method of claim 22 , wherein the distance metric between the given bifurcation and the one or more points of interest corresponds to a minimum distance of the distances between the bifurcation and each of the one or more points of interest.

24. The method of claim 20 , further comprising:

defining a cut-surface throughout volumetric data; and wherein

the rendering the image of the volumetric data comprises rendering an image of the intersection of the cut-surface and the tubular object.