Measuring hippocampal neuroanatomical asymmetry to better diagnose Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia, and an accurate diagnosis confers many clinical research and patient care benefits. The current research-setting criteria needs to consider at least one supportive biomarker before diagnosing a subject with AD, and brain atrophy measured using structural magnetic resonance is one of them. Yet, brain atrophy is currently defined using only volumetric information which could obviate localized morphological variations. We measured hippocampal neuroanatomical asymmetry from MR images of 417 subjects as a surrogate measurement of brain atrophy, anticipating that it would have a better sensitivity than volumetric information regarding differences between healthy controls and subjects with AD. Asymmetry was defined in terms of the overlapping voxels between left and right hippocampi after a co-registration process. We found a significant difference (p-value = 0.007) in discrimination power between hippocampal volume and neuroanatomical asymmetry. This result suggests that neuroanatomical asymmetry should be further studied to determine whether it could replace the current brain atrophy biomarker.