1/44 early detection of alzheimer’s disease based on cortical thickness measurements master’s...
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Early Detection Of Alzheimer’s Disease
Based on Cortical Thickness Measurements
Master’s Thesis Defence
Morten Simoni SpjuthFlemming H Gravesen
27. June – 2006
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Discussion
Pros• Automatic• Not biased by prior landmarks • Observer independent
Cons• Difficult to evaluate• Restricted to thickness analysis
No prior knowledgeVery few miss-registered (sulci gyri)Similar results as the literature
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Group Models of Cortical Thickness
- Thickness distribution for each point- A statistical representation of cortices
- Spatial information retained- Enables group comparisons
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Average Representation of Cortical Thickness in Young and Healthy Subjects
sulci: 2.44mm (std: 0.13)gyri: 3.12mm (std: 0.20)
Von Economo (1929)
Left
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Average Representation of Cortical Thickness in mild AD
AD:
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Average Representation of Cortical Thickness in mild AD
AD:
Young and healthy:
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Group Differences
Mild AD vs. Healthy age-matchedCan the thickness differences be related to AD?Comparison to other studies:
- Braak & Braak (1991)- O’Brien (2001)- Lerch et.al. (2004)- Thompson et.al. (2003)
Lateral view Medial view
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Feature reduction- Principal component analysis
Feature selection- Separability measure
Normalization- Mean thickness removed- Age-matched (atrophy in ageing)
Classification of mild AD
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Results
MMSE-score of AD patients: 23.3 (std: 2.6)Segmentation parameters
Two additional young and healthy subjects
Flemming
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Investigation of atrophy using PCA
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Perspectives
Investigation of AD-progression:- Longitudinal study- Understanding of the disease- Linear/stepwise progression- Mapping treatment effects
Other diseases causing cerebral atrophy:- Frontotemporal dementia- Huntington etc.
Clinical use- Complementary to psychological testing
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Conclusion
- Possible to detect AD at an early stage
- Statistical model of cortical thickness
- Developed method for inter subject comparison- Registration favouring thickness comparisons
- Quantitative measure- Observer independent tool- In vivo - Investigation of cortical thickness differences