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

Chapter 5 Quantitative shape analysis of hippocampus in AD 131
(a) Left hippocampus, the first mode
(b) Right hippocampus, the first mode
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Figure 5.12: Variation modes captured by Principal Component Analysis
(PCA) on hippocampal subregions best correlated to memory indices (logical
memory, AVLT, ADAS memory), color-coded map showing the magnitude of
variation described by the mode. LS, α = 0.01, MS, mode 1. (From left to
right: superior, medial, inferior, lateral)
filtered out in MS. This may explain the better performance local size-and-shape
variations (LS + MR) than the shape models (LS + MS) on the local scale, in
addition to the discriminant ability of the size factor present in MR.
In our experiments, the higher training error than the testing error might be due
to the difference in the demographics between the training and the testing set.
The average age of the AD subjects in the testing set is slightly older than in the
training set, which may explain the lower testing error in the disease classification.
The higher training error is also present when using only the volume as the feature
for classification (77.6% OOB vs 83.5% on testing set).