DBP3:Utah:AutoEndoSeg

Notes on the Endocardial Segmentation Algorithm

Algorithm is a multi-atlas segmentation.

1. Register (cropped) heart region of patient DEMRI to all of the n atlas DEMRI images and record n minimum metric values (mutual information)
2. Transform all n atlas segmentations to patient DEMRI space
3. Segmentation is a weighted average of the transformed atlas segmentation, where weights are determined by the mutual information values from step 1
4. Pick a threshold as your segmentation

Notes on Yi's Slicer Module

• The exposed parameter is the ratio of pixel samples for mutual information to the total number of pixels in the image.
• We could also expose the threshold parameter in the final step
• We can change or add atlas datasets by copying into the appropriate directory and editing the text file that lists them
• Uses the ITK mutual information code. Does affine registration followed by b-spline
• We will partner with Yi for module development at the Jan 2012 project week

Initial Experiences

• Comparison of GA Tech and Utah-derived segmentations

(click to enlarge)

GA Tech Segmentation	Utah Segmentation	Thresholding Difference
Segmentation of an atlas image by GA Tech, using their endocardial auto-segmentation algorithm.	Segmentation of the same image with the same algorithm by Utah.	User-based variability in thresholding the probability mask output. (Green region - Utah; white region - GA Tech).