1. CPR Curved Planar Reformation A. Kanitsar 1, D. Fleischmann 2, R. Wegenkittl 3, P. Felkel 3, M. E. Gröller 1 1 Institute of Computer Graphics and Algorithms Vienna University of Technology 2 Department of Radiology University of Vienna 3 VRVis Research Center Vienna,Austria

2. Armin KanitsarVienna University of Technology 2 / 18 Vessel Investigation using CTA ~ 1500 slices vessels are not visible entirely within just one slice Visualization is essential!

3. Armin KanitsarVienna University of Technology 3 / 18 Significance of Visualization (1) vessel lumen in MIP not visible! MIP DSA

4. Armin KanitsarVienna University of Technology 4 / 18 CPR Basics Resample an image visualizing a vessel in its entirety. Resample an image visualizing a vessel in its entirety. CPRDataset Points Tracking Path

5. Armin KanitsarVienna University of Technology 5 / 18 Significance of Visualization (2) MIP CPRDSA

6. Armin KanitsarVienna University of Technology 6 / 18 How To Display The Plane? Provide good overview Provide good overview Allow fast inspection Allow fast inspection Easy to handle Easy to handle Projected CPR

7. Armin KanitsarVienna University of Technology 7 / 18 Projected CPR Resample each generating line from data set Resample each generating line from data set Project to corresponding position of the image Project to corresponding position of the image Compositing using MIP/AVG/MinIP Compositing using MIP/AVG/MinIP - Isometry not maintained - Occlusions possible - Geometric artifacts + Spatial perception very good

8. Armin KanitsarVienna University of Technology 8 / 18 Stretched CPR - Sensitive to high curvature within vessel + Length-preserving + No occlusions possible + Reduced geometric artifacts Resample each generating line from data set Resample each generating line from data set Unroll plane in image Unroll plane in image Height of the image depends on: Height of the image depends on:  Vessel length  Curvature of the vessel in image

9. Armin KanitsarVienna University of Technology 9 / 18 Straightened CPR - No spatial relationship - Rotating frame + Length-preserving + No occlusions possible Resample each generating line from cross-section Resample each generating line from cross-section Height of the image depends on: Height of the image depends on:  Vessel length

10. Armin KanitsarVienna University of Technology 10 / 18 Method Comparison

11. Armin KanitsarVienna University of Technology 11 / 18 Methods Comparison ProjectedStretchedStraightened Perceptionhighmediumlow Isometrynoyesyes Occlusionspossiblynono

12. Armin KanitsarVienna University of Technology 12 / 18 CPR Limitations vessel lumen calcification Pseudo stenosis due to inaccurate centerline detection Pseudo stenosis due to inaccurate centerline detection Longitudinal sections do not cover the whole vessel Longitudinal sections do not cover the whole vessel One vessel per image results in large number of images to investigate One vessel per image results in large number of images to investigate

13. Armin KanitsarVienna University of Technology 13 / 18 Thick CPR Compositing: MIP/AVG/MinIP Compositing: MIP/AVG/MinIP ~3mm

14. Armin KanitsarVienna University of Technology 14 / 18 Rotating CPR vessel-lumen calcification PRSTSA

15. Armin KanitsarVienna University of Technology 15 / 18 Multi-Path CPR (1/3) 6 Paths FArteryPTArteryPTArteryFArteryrightATArteryleftATArtery Medial Axis Reformation (He01)

16. Armin KanitsarVienna University of Technology 16 / 18 Multi-Path CPR (2/3)

17. Armin KanitsarVienna University of Technology 17 / 18 Multi-Path CPR (3/3) Projected – Multi-Path CPR Stretched – Multi-Path CPR

18. Armin KanitsarVienna University of Technology 18 / 18 Thank You For Your Attention!