An%20Interactive%20Virtual%20Endoscopy%20Tool

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

• Background and Motivation
• Interactive System
• Central Path Planning Algorithm
• Synchronized Virtual Endoscopy
• Conclusion

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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?

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Conventional Endoscopy

• advantages
• minimally invasive
• high resolution
• interactivity

• disadvantages
• can be painful and uncomfortable
• limited exploration

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Conventional Medical Imaging
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Conventional Visualization

• advantages
• non invasive
• information on tissue shape through and beyond
  walls of organ

• disadvantages
• mentally align contiguous slides
• lower resolution than video

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Segmentation Volume
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3D Reconstruction Model
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3D Visualization
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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
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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

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Virtual Colonoscopy
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System Requirements

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

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Presentation Overview

• Background and Motivation
• Interactive System
• Central Path Planning Algorithm
• Synchronized Virtual Endoscopy
• Conclusion

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Display
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Navigation Interface
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Cross Reference
Provided by Arjan Welmers
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Path Update
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Applications Middle Ear
Thomas Rodt Soenke Bartling
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Applications Cardiovascular
Provided by Bonglin Chung
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Presentation Overview

• Background and Motivation
• Interactive System
• Central Path Planning Algorithm
• Synchronized Virtual Endoscopy
• Conclusion

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Automated Path Planning

• Goal
• provide a create path button that
• produces a centerline inside a 3D
• model of any topology

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Input
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Output
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Step 1 Produce a Labelmap
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Step 2 Produce a distance map
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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

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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

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Step 5 Results
Running Time 7s
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Step 5 Results
Running Time 3s
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Presentation Overview

• Background and Motivation
• Interactive System
• Central Path Planning Algorithm
• Synchronized Virtual Endoscopy
• Conclusion

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Synchronized Virtual Colonoscopy
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Dynamic Programming
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Results
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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.

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Acknowledgements

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

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Thank You!
Steve Haker, Hoon Ji, Connie Sehnert
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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

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Cross Reference
Provided by Arjan Welmers
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3D Visualization
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Synchronized Virtual Endoscopy