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Published on: November 14, 2017
Automated measurement of hippocampal atrophy using fluid-registered serial MRI in AD and controls
Josephine Barnes1, Emma B Lewis, Rachael I Scahill
1Dementia Research Centre, University College London, Institute of Neurology, Queen Square, London, UK. j.barnes@dementia.ion.ucl.ac.uk
Objective:
To assess hippocampal atrophy rates calculated from fluid registration methods.
Methods:
Hippocampi were segmented on baseline and registered-repeat scans of 32 probable Alzheimer disease (AD) subjects and 55 controls. Fluid-based atrophy rates were calculated.
Results:
In AD patients, the mean (SD) atrophy rates for manual, fluidly propagated, and Jacobian methods were 5.09 (3.59), 5.34 (3.43), and 3.55 (2.70) (percentage per year). In controls, atrophy rates were 1.31 (2.00), 0.89 (0.75), and 0.56 (1.12) (percentage per year). In AD, fluid propagation and manual rates were similar in means (P = 0.55) and variances (P = 0.71). Jacobian rates were smaller in mean (P = 0.002) and variance (P = 0.026) than in manual rates. In controls, fluid-propagated rates were similar in mean to manual rates (P = 0.12), but less variable (P < 0.0001). Jacobian rates were smaller in mean (P = 0.014) and less variable (P < 0.0001) than in manual rates. Both fluid methods were superior to manual measures in separating AD from controls (P < 0.0001).
Conclusions:
Fluid-based methods may be useful in large serial hippocampal studies.
Insights
Fluid-based methods accurately measure hippocampal atrophy in Alzheimer's disease (AD) patients and controls. These techniques show promise for large-scale serial studies evaluating brain changes.
Area of Science:
- Neuroimaging
- Medical Statistics
- Alzheimer's Disease Research
Background:
- Alzheimer's disease (AD) is characterized by progressive neurodegeneration, particularly affecting the hippocampus.
- Accurate quantification of hippocampal atrophy is crucial for understanding AD progression and evaluating therapeutic interventions.
- Traditional manual segmentation methods for atrophy calculation can be time-consuming and prone to variability.
Purpose of the Study:
- To evaluate the efficacy of fluid registration-based methods for calculating hippocampal atrophy rates.
- To compare the performance of fluid-based methods against manual segmentation in differentiating Alzheimer's disease patients from healthy controls.
Main Methods:
- Hippocampal volumes were segmented from baseline and repeat MRI scans of 32 probable AD patients and 55 controls.
- Atrophy rates were computed using manual segmentation, fluidly propagated registration, and Jacobian-based methods.
- Statistical analyses compared the means and variances of atrophy rates across methods and groups.
Main Results:
- Fluid-based methods demonstrated comparable mean atrophy rates to manual methods in AD patients.
- Jacobian-based rates were significantly lower than manual rates in both AD patients and controls.
- Both fluid registration methods showed superior ability to distinguish between AD patients and controls compared to manual measures.
Conclusions:
- Fluid-based methods offer a reliable and sensitive approach for quantifying hippocampal atrophy.
- These advanced techniques are well-suited for large-scale longitudinal studies investigating Alzheimer's disease.
- Fluid registration methods enhance the diagnostic power in differentiating AD from healthy aging.
