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Updated: May 17, 2025
Basics of Multivariate Analysis in Neuroimaging Data
Published on: July 24, 2010
Multimodal MRI accurately identifies amyloid status in unbalanced cohorts in Alzheimer's disease continuum
Giorgio Dolci1,2,3, Charles A Ellis3, Federica Cruciani2
1Department of Computer Science, University of Verona, Verona, Italy.
Abstract:
Amyloid-β (Aβ) plaques in conjunction with hyperphosphorylated tau proteins in the form of neurofibrillary tangles are the two neuropathological hallmarks of Alzheimer's disease. It is well-known that the identification of individuals with Aβ positivity could enable early diagnosis. In this work, we aim at capturing the Aβ positivity status in an unbalanced cohort enclosing subjects at different disease stages, exploiting the underlying structural and connectivity disease-induced modulations as revealed by structural, functional, and diffusion MRI. Of note, due to the unbalanced cohort, the outcomes may be guided by those factors rather than amyloid accumulation. The partial views provided by each modality are integrated in the model, allowing to take full advantage of their complementarity in encoding the effects of the Aβ accumulation, leading to an accuracy of 0.762 ± 0.04. The specificity of the information brought by each modality is assessed by post hoc explainability analysis (guided backpropagation), highlighting the underlying structural and functional changes. Noteworthy, well-established biomarker key regions related to Aβ deposition could be identified by all modalities, including the hippocampus, thalamus, precuneus, and cingulate gyrus, witnessing in favor of the reliability of the method as well as its potential in shedding light on modality-specific possibly unknown Aβ deposition signatures.
Insights
This study identifies amyloid-β (Aβ) positivity in Alzheimer's disease using multimodal MRI. The integrated approach accurately detects Aβ status, aiding early diagnosis and revealing disease-related brain changes.
Area of Science:
- Neurology
- Medical Imaging
- Biomarkers
Background:
- Alzheimer's disease (AD) is characterized by amyloid-β (Aβ) plaques and neurofibrillary tangles.
- Early diagnosis of Aβ positivity is crucial for timely intervention in AD.
- Unbalanced cohorts and disease heterogeneity pose challenges in identifying Aβ status.
Purpose of the Study:
- To develop a multimodal MRI approach for detecting Aβ positivity in an unbalanced cohort.
- To integrate structural, functional, and diffusion MRI data to capture Aβ accumulation effects.
- To assess the reliability and specificity of MRI modalities in identifying Aβ-related brain changes.
Main Methods:
- Utilized structural, functional, and diffusion MRI data from subjects at various disease stages.
- Integrated partial views from each MRI modality into a unified model.
- Employed post hoc explainability analysis (guided backpropagation) to identify key brain regions.
Main Results:
- Achieved an accuracy of 0.762 ± 0.04 in identifying Aβ positivity.
- Highlighted structural and functional brain changes associated with Aβ accumulation.
- Confirmed known biomarker regions (hippocampus, thalamus, precuneus, cingulate gyrus) and suggested novel signatures.
Conclusions:
- Multimodal MRI effectively captures Aβ positivity, even in unbalanced cohorts.
- The integrated approach leverages complementary information from different MRI sequences.
- The method shows potential for early AD diagnosis and discovering new Aβ deposition biomarkers.
