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Docteur de l'université Automatic Segmentation and Shape Analysis ...

Docteur de l'université Automatic Segmentation and Shape Analysis ...

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Chapter 3 Hippocampal segmentation using multiple atlases 69<br />

DSC<br />

DSC<br />

0.83 0.84 0.85 0.86 0.87<br />

20 40 60 80 100 120<br />

No. of selected atlases<br />

NMI<br />

Correlation<br />

LAR<br />

MMR−NMI λ=0.7<br />

MMR−Correlation λ=0.7<br />

(a) Performance of atlas selection strategies on NC atlases.<br />

0.81 0.82 0.83 0.84 0.85<br />

20 40 60 80<br />

No. of selected atlases<br />

NMI<br />

Correlation<br />

LAR<br />

MMR−NMI λ=0.7<br />

MMR−Correlation λ=0.7<br />

(b) Performance of atlas selection strategies on AD atlases.<br />

Figure 3.8: The average Dice similarity coefficient (DSC) of left <strong>and</strong> right hippocampi<br />

using locally weighted voting (LWV) on the normal control (NC) atlas<br />

set. The atlases are selected according to image similarity ranking, maximal<br />

marginal relevance (MMR) re-ranking <strong>and</strong> least angle regression sequence.<br />

3.5 Summary<br />

We used a supervised approach to produce a set of population specific atlases from<br />

el<strong>de</strong>rly subjects using multi-atlas based segmentation-propagation. Starting with<br />

18 IBSR atlases, 16 images from el<strong>de</strong>rly population well segmented were ad<strong>de</strong>d<br />

to the atlas set. More images were ad<strong>de</strong>d in the second iteration. The result

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