1.  Interactive Segmentation For Image Guided Therapy Ohad Shitrit & Tsachi Hershkovich Superviser: Dr. Tammy Riklin Raviv Ben-Gurion University of the Negev

2. What are we going to speak about? Tsachi H. & Ohad S.  Computed Tomography  Motivation  Mathematical introduction  Problem definition  Energy  Gradient Descent  The system  Results  Conclusion & Future work

3. Tsachi H. & Ohad S. Computed Tomography (CT) Spiral Cone-Beam Scanning for Computed Tomography. Ge Wang, 2003 (All rights reserved)

4. Tsachi H. & Ohad S. Computed Tomography (CT) Spiral Cone-Beam Scanning for Computed Tomography. Ge Wang, 2003 (All rights reserved)  X-Ray Projection using radon transform

5. Tsachi H. & Ohad S. Computed Tomography (CT)  Radon transform as one dimensional Fourier transform  Reconstructing the image with the inverse Fourier transform

6. Why is there any need for interactive segmentation ? Tsachi H. & Ohad S.

8. Why is there any need for interactive segmentation?  Volume estimation is critical for further treatment  Therapist knowledge is essential for final decisions  Fast and accurate analysis might save life Tsachi H. & Ohad S.

11. “Active Contour” But first things first… Tsachi H. & Ohad S.

12. Probabilistic Model Based on Gaussian Mixture(GM) Tsachi H. & Ohad S.  We will define the Probability of a Voxel (3D pixel) to belong to the Object Or to the Background:

13. A CT scan Histogram of a brain with Cerebral hemorrhage Tsachi H. & Ohad S.

14. Level Set Function -

15. Tsachi H. & Ohad S. Mathematical Issues

16. Tsachi H. & Ohad S. [Riklin Raviv, Van Leemput, Menze, Wells, Golland, Medical Image Analysis, 2011]

17. Tsachi H. & Ohad S. To achieve the optimized segmentation we maximize the joint distribution: [Riklin Raviv, Van Leemput, Menze, Wells, Golland, Medical Image Analysis, 2011]

18. Tsachi H. & Ohad S. Energy Functional  Using the following relationship :  Allows us to formulate our problem as an energy minimization problem  Summing all contributions from each voxel

19. Tsachi H. & Ohad S. Image Likelihood Term  Assuming Gaussian Mixtures Model (GMM)

20. Tsachi H. & Ohad S. Smoothness Term  Objects in nature are continuous  Trade off between smoothness and sensitivity  Fine tuning is needed

21. Tsachi H. & Ohad S. User Interaction Term

22. Tsachi H. & Ohad S. Gradient Descent The gradient descent is an iterative process which leads to the minimum of the Energy term.

23. Tsachi H. & Ohad S. Block Diagram – Entire System [Riklin Raviv, Van Leemput, Menze, Wells, Golland, Medical Image Analysis, 2011]

24. Entire System 3D

25. Tsachi H. & Ohad S. Entire System 3D

26. Tsachi H. & Ohad S. Entire System 3D

27. Tsachi H. & Ohad S. Entire System 3D

28. Tsachi H. & Ohad S. Entire System 3D

29. Tsachi H. & Ohad S. Entire System 3D

30. Tsachi H. & Ohad S. Entire System 3D

31. Tsachi H. & Ohad S. Entire System 3D

32. Tsachi H. & Ohad S. Entire System 3D

33. Tsachi H. & Ohad S. Entire System 3D

34. Tsachi H. & Ohad S. Entire System 3D

35. Tsachi H. & Ohad S. Entire System 3D

36. Tsachi H. & Ohad S. Entire System 3D

37. Tsachi H. & Ohad S. Entire System 3D

38. Tsachi H. & Ohad S. Entire System 3D

39. Tsachi H. & Ohad S. Performance DiceSensitivitySpecificityAccuracy Automatic 0.874±0.0340.864±0.0730.998±0.00190.996±0.0033 With user interaction 0.905±0.0270.870±0.0630.999±0.00030.997±0.0022

40. Tsachi H. & Ohad S. Data  Provided by Dr. Ilan Shelef, Department of Radiology, Soroka University Medical Center and Zlotowski Center for Neuroscience, Ben- Gurion University of the Negev.  Modality: CT Brilliance 64  Resolution: 512x512xZ (Z = 90-100) X x Y x Z = 0.48 x 0.48 x 3 [mm]  Z axis with 1.5[mm] overlap

41. Conclusion  Semi-automatic segmentation tool  Probabilistic model  User Interface  Collaboration with Soroka Medical Center Tsachi H. & Ohad S.

42. Future work  Adjustments to other modalities (MRI)  Handle with various of structures  User-Machine dialog in the medical world Tsachi H. & Ohad S.

43. User Interface

44. Questions? Thank you. Demo - http://youtu.be/Jb-6VDid37shttp://youtu.be/Jb-6VDid37s