MRI-derived entorhinal and hippocampal atrophy in incipient and very mild Alzheimer's disease
B C Dickerson1, I Goncharova, M P Sullivan
1Department of Neurological Sciences, Rush University, Chicago, IL 60612, USA.
Abstract:
With high resolution, quantitative magnetic resonance imaging (MRI) techniques, it is now possible to examine alterations in brain anatomy in vivo and to identify regions affected in the earliest stages of Alzheimer's disease (AD). In this study, we compared MRI-derived entorhinal and hippocampal volume in healthy elderly controls, patients who presented at the clinic with cognitive complaints, but did not meet criteria for dementia (non-demented), and patients with very mild AD. The two patient groups differed significantly from controls in entorhinal volume, but not from each other; in contrast, they differed from each other, as well as from controls, in hippocampal volume, with the mild AD cases showing the greatest atrophy. Follow-up clinical evaluations available on 23/28 non-demented patients indicated that 12/23 had converted to AD within 12-77 months from the baseline MRI examination. Converters could be best differentiated from non-converters on the basis of entorhinal, but not hippocampal volume. These data suggest that although both the EC and hippocampal formation degenerate before the onset of overt dementia, EC volume is a better predictor of conversion.
Insights
Early Alzheimer's disease (AD) detection is possible using MRI brain scans. Entorhinal cortex volume, not hippocampal volume, best predicts conversion to AD in patients with cognitive complaints.
Area of Science:
- Neurology
- Radiology
- Neuroimaging
Background:
- Alzheimer's disease (AD) diagnosis relies on identifying early anatomical changes in the brain.
- High-resolution magnetic resonance imaging (MRI) enables in vivo examination of brain structures.
Purpose of the Study:
- To compare entorhinal and hippocampal volumes in healthy controls, patients with cognitive complaints, and those with very mild AD.
- To determine if entorhinal or hippocampal volume better predicts conversion to AD.
Main Methods:
- Quantitative MRI was used to measure entorhinal and hippocampal volumes.
- Comparison of regional brain volumes across three groups: healthy elderly controls, non-demented patients with cognitive complaints, and very mild AD patients.
Main Results:
- Both non-demented and very mild AD groups showed reduced entorhinal volume compared to controls, with no significant difference between patient groups.
- Hippocampal volume was significantly reduced in both patient groups compared to controls, with the greatest atrophy observed in the very mild AD group.
- Follow-up revealed 12/23 non-demented patients converted to AD; entorhinal volume, not hippocampal volume, differentiated converters from non-converters.
Conclusions:
- Both entorhinal cortex (EC) and hippocampus degenerate before overt dementia symptoms appear.
- Entorhinal cortex volume is a more sensitive predictor of future Alzheimer's disease conversion than hippocampal volume.
Related Concept Videos
01:23Alzheimer Disease ll: Pathophysiology
01:22Dementia l: Introduction
01:26Alzheimer's Disease: Overview
The clinical diagnosis of AD hinges on the presence of memory and other cognitive impairments. Biomarkers, such as changes in Aβ and tau...