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Chapter 3 Hippocampal segmentation using multiple atlases 65
(a) (b) (c) (d)
Figure 3.5: Comparison of result hippocampal segmentation of one example
NC case by fusing 31 atlases selected according to different criteria. (a) SNT
segmentation; (b) correlation (DSC=0.861); (c) NMI (DSC=0.865); (d) LAR
(DSC=0.871).
While in terms of the partial moment µ2, the distributions of the votes using 40
atlases are consistently closer to the unanimous agreement.
All the 40 atlases visually inspected and selected are from NC subjects. Since IBSR
atlases are from NC subjects, the well segmented images using IBSR set are more
likely to come from NC population. This effect is reflected in the measurement of
agreement. The NC atlases are more easily to agree upon NC cases compared to
AD ones. The trend is consistently present as measure by the partial moment µ2,
while it is not very clearly shown in terms of entropy HP .
3.4.2 Atlas selection strategies
3.4.2.1 Materials
Data used in the experiments were obtained from the Alzheimer’s Disease Neu-
roimaging Initiative (ADNI) database. The ADNI was launched in 2003 by the
National Institute on Aging (NIA), the National Institute of Biomedical Imaging
and Bioengineering (NIBIB), the Food and Drug Administration (FDA), private
pharmaceutical companies and non-profit organizations, as a $60 million, 5-year
public-private partnership. The primary goal of ADNI has been to test whether
serial MRI, positron emission tomography (PET), other biological markers, and
clinical and neuropsychological assessment can be combined to measure the pro-
gression of MCI and early AD. Determination of sensitive and specific markers of
very early AD progression is intended to aid researchers and clinicians to develop
new treatments and monitor their effectiveness, as well as lessen the time and cost