Improved 3D Live-Wire Method with Application to 3D CT Chest Image Analysis

1. Improved 3D Live-Wire Method with Application to 3D CT Chest Image Analysis Kongkuo Lu and William E. Higgins Penn State University Department of Electrical Engineering University Park, PA 16802, USA SPIE Medical Imaging 2006: Image Processing, San Diego, CA, 14 Feb. 2006.

2. Motivation • ROI segmentation is important, but difficult • Manual slice tracing always works --but it is time consuming • Automated segmentation avoids user intervention--but it is strongly application dependent • Semiautomatic methods allow for full user control while reducing human involvement

3. Prior Work 2D Live Wire: • Mortensen et al. (IEEE Computers in Cardiology 1992) • Mortensen et al. (Graphical Models and Medical Imaging 1998) • Falcão et al. (SPIE Medical Imaging 1996) • Falcão et al. (Graphical Models and Medical Imaging 1998) 3D Live Wire: • Falcão et al. (Medical Image Analysis 2000) • Schenket al. (MICCAI 2000) • Salahet al. (Workshop Bildverarbeitung in der Medizin 2005) • Hamarneh et al. (SPIE Medical Imaging 2005) • König et al. (SPIE Medical Imaging 2005)

4. Cost Function New Cost! Cost Function: * Three components were derived from Mortensen 98

5. |r-p| D’(r) |r-p| D(r) D’(r) r p D(r) r D(p) D’(p) p D’(p) Gradient Direction |r-p| r D’(r) p D(r) D(p) D’(p) Gradient Direction: New Gradient Direction:

6. Gradient Direction Live Wire using old cost Live wire with new cost

7. 2D Graph-Search Algorithm 2D graph-search algorithm for the live-wire method (Modified based on Mortensen 98)

8. 41 35 30 33 47 29 25 23 25 29 19 17 19 29 20 13 16 29 44 14 10 13 19 33 39 62 37 29 34 15 7 7 12 14 24 29 36 27 24 30 16 9 3 8 4 8 13 20 19 22 33 11 5 0 1 5 11 13 14 20 28 40 19 10 8 4 14 15 18 22 24 29 2D Live Wire Introduction * Derived from Mortensen 98

9. 2D Live Wire Example Segment ROI using 2D Live Wire

10. 3D Live Wire Coro. Sag. Trans. 2D live wire on Sag. slice 1 2D live wire on Sag. slice 2 2D live wire on 2 Coro. slices Generate seeds on every slice in Trans. direction Running 3D live wire in Trans. direction

11. Slice i+1 Distance Slice i-1 Distance 3D Live Wire Slice i+2 Reference Slice Slice i Slice i-2 2D live wire on ref. slice Proj. result onto neighbor slices Proj. results onto following slices Define boundaries using 2D live wire

12. Segmentation result 2D Results 2D ROI * Three ROIs used in tests

13. 2D Live Wire Evaluation Three Factors: (derived from Falcão98, 00) Efficiency -- Processing time to segment an ROI Repeatability -- Accuracy --

14. 2D Live Wire Evaluation Segmentation Reproducibilities Inter-Operator Segmentation Reproducibilities

15. 2D Live Wire Evaluation Summary: Time ratio between manual tracing and 2D live wire: * Efficiency comparison based on accuracy higher than 95%

16. ROI R33 ROI R32 ROI R31 3D Results * Three 3D ROIs used in tests

17. 3D Results 3D Segmentation Results

18. 3D Live Wire Evaluation Summary: Time ratio between 3D live wire and 2D live wire / manual slice tracing: * Efficiency comparison based on accuracy higher than 90%

19. 3D Live Wire Example

20. Comments on 3D Live Wire Top view Bottom view

21. Summary • Introduce new gradient direction cost • 2D live wire works very well 2D Live Wire: 3D Live Wire: • Reliable and efficient

22. Thanks!