An Interactive Virtual Endoscopy Tool With Automated Path Generation

1. An Interactive Virtual Endoscopy Tool With Automated Path Generation Delphine Nain, MIT AI Laboratory. Thesis Advisor: W. Eric. L Grimson, MIT AI Laboratory.

2. Presentation Overview • Background and Motivation • Interactive System • Central Path Planning Algorithm • Synchronized Virtual Endoscopy • Conclusion

3. Medical Motivation • Cancer is the 2nd cause of death in the US • 43 % of people have a risk to be diagnosed with cancer • Out of those 88 % are cancer in inner organ • How can “see” inside the body to screen and cure?

4. Conventional Endoscopy • advantages: • minimally invasive • high resolution • interactivity • disadvantages: • can be painful and uncomfortable • limited exploration

5. Conventional Medical Imaging

6. Conventional Visualization • advantages: • non invasive • information on tissue shape through and beyond walls of organ • disadvantages: • mentally align contiguous slides • lower resolution than video

7. Segmentation: Volume

8. 3D Reconstruction : Model

9. 3D Visualization

10. Virtual Endoscopy • Combines strengths of previous alternatives on patient-specific dataset • Spatial exploration • Cross-correlation with original volume Compact and Intuitive way to explore huge amount of information

11. Virtual Endoscopy: advantages • clinical studies: • planning and post-operation: generates views that are not observable in actual endoscopic examinations • color coding algorithms give supplemental information

12. Virtual Colonoscopy

13. System Requirements • Combination of Interactivity and Automation is key • Cross Reference between 3D models and grayscale volumes

14. Presentation Overview • Background and Motivation • Interactive System • Central Path Planning Algorithm • Synchronized Virtual Endoscopy • Conclusion

15. Display

16. Navigation Interface

17. Cross Reference Provided by Arjan Welmers

18. Path: Update

19. Applications: Middle Ear ThomasRodt Soenke Bartling

20. Applications: Cardiovascular Provided by Bonglin Chung

21. Presentation Overview • Background and Motivation • Interactive System • Central Path Planning Algorithm • Synchronized Virtual Endoscopy • Conclusion

22. Automated Path Planning • Goal: provide a “create path” button that produces a centerline inside a 3D model of any topology

23. Input

24. Output

25. Step 1: Produce a Labelmap

26. Step 2: Produce a distance map

27. Step 3: Create a Graph Create a Graph description of the Distance Map • Nodes are voxels inside the model • Edge weight are 1/(distance)2 from the wall of the organ

28. Step 4: Run modified Dijkstra Dijkstra algorithm is a single source shortest path algorithm • We use a binary heap • An optimization: keep an evolving front, stop when reach the end node

29. Step 5: Results Running Time: ~7s

30. Step 5: Results Running Time: ~3s

31. Presentation Overview • Background and Motivation • Interactive System • Central Path Planning Algorithm • Synchronized Virtual Endoscopy • Conclusion

32. Synchronized Virtual Colonoscopy

33. Dynamic Programming

34. Results

35. Conclusion • Combination of Automation and Interactivity is key • Cross Reference is important • Synchronized Fly-Throughs is novel contribution Publication: D. Nain, S. Haker, E. Grimson, R. Kikinis “An Interactive Virtual Endoscopy Tool”, IMIVA workshop, MICCAI 2001.

36. Acknowledgements • Ron Kikinis • Steve Haker • Lauren O’Donnell • David Gering • Carl-Fredrik Westin • Peter Everett • Sandy Wells • Eric Cosman • Polina Golland • Soenke Bartling • John Fisher • Mike Halle • Ferenc Jolesz

37. Thank You! Steve Haker, Hoon Ji, Connie Sehnert

38. Correspondance VC = T is transformation matrix (translation or rotation along local axis) To uniquely determine the coordinates of the virtual camera: • coordinates of camera: • VCnew = VCold* T • coordinates of the focal point: • FPnew = VCnew* T

39. Cross Reference Provided by Arjan Welmers

40. 3D Visualization

41. Synchronized Virtual Endoscopy