Alzheimer's Imaging Consortium.

Area of Science:

• Neuroscience
• Medical Imaging
• Gerontology

Background:

• The hippocampus (HC) is a crucial biomarker in Alzheimer's disease (AD).
• Ventricular enlargement, indicative of brain atrophy, is also observed in AD.
• The relationship between ventricular size and cognitive function requires further exploration.

Purpose of the Study:

• To evaluate lateral-temporal horn ventricular measurements as a correlate for cognitive function in Alzheimer's disease.
• To compare the association of hippocampal volume, ventricular volume, and their ratio with cognitive domains.

Main Methods:

• Analysis of cognitive and MRI data from 481 cognitively healthy (CH), 548 mild cognitively-impaired (MCI), and 222 AD individuals from the ADNI dataset.
• Segmentation of the hippocampus (HC) and lateral ventricles (LV) using a Convolutional Neural Network.
• Calculation of the hippocampus-to-ventricle ratio (HVR) as a measure of medial-temporal integrity and assessment of correlations with memory, executive function, and language.

Main Results:

• Lateral ventricular (LV) volume showed stronger negative correlations with cognition than hippocampal (HC) volume, especially in CH and MCI individuals.
• The hippocampus-to-ventricle ratio (HVR) demonstrated robust associations with cognitive functions, often outperforming individual HC or LV measures.
• In AD patients, HC and HVR showed stronger correlations with memory than LV, while HVR and LV exceeded HC in executive function correlations across all groups.

Conclusions:

• Lateral ventricular enlargement is a significant correlate of cognitive decline, potentially more so than hippocampal atrophy alone.
• The hippocampus-to-ventricle ratio (HVR) provides a comprehensive and robust measure of medial-temporal integrity.
• Ventricular expansion is highlighted as a key biomarker for AD research and clinical evaluation.