1. Vision REU Week 3

2. Image registration  Used mutual information-based registration from ITK Ben SchoepkeREU Week 36/8/07 Fixed imageMoving image Pre-registrationPost-registration

3. Segmentation  Edema is arbitrarily shaped Ben SchoepkeREU Week 36/8/07

4. Mean shift segmentation  Need non-parametric segmentation: mean shift! Ben SchoepkeREU Week 36/8/07 Comaniciu, D., Meer, P.: Mean shift: A robust approach toward feature space analysis. IEEE Trans. Pattern Anal. Mach. Intell. 24(5) (2002) 603–619

5. Experimentation  Register images to T1 > Segment with mean shift > Compare Ben SchoepkeREU Week 36/8/07 T1T1e FLAIRT2 Ground truth edema estimate (un-segmented FLAIR image)

6. Experimentation results  Observed that edema is visible in FLAIR and T2, not visible in T1 and T1E  Run each segmented image through high pass filter  Edema segmented image = (FLAIR && T2) && !(T1 && T1E)  Problem: very sensitive to threshold selection Ben SchoepkeREU Week 36/8/07 Ground truth edema estimateResult

7. Next week  Use brain atlas to remove false positives  Probability of observing edema in CSF regions is ~0  Perform region-based analysis rather than pixel-by-pixel  Continue developing algorithm  Which modalities to use?  Test different slices  Merge with tumor segmentation code  3D segmentation Ben SchoepkeREU Week 36/8/07 Probabilistic brain atlas. Non-CSF is blue. Source: Leach et al.