Prevalence of hippocampal morphologic variants between healthy elderly subjects and patients with Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease with atrophic changes in the temporal lobe. Enlargement of cerebrospinal fluid (CSF) spaces, hippocampal sulcus (HS) enlargement, or an increase in the number or size of hippocampal cavities (HCs) could be associated with medial temporal lobe atrophy (MTA). In this study, we assessed the relation of these CSF spaces with AD.

A total 36 demented patients with diagnosis of Alzheimer (Mini-Mental State Examination (MMSE) ≤25) and 36 non-demented elderly individuals were referred for basic magnetic resonance imaging (MRI) before initiating anti-dementia therapy in the demented group. Two observers assessed the maximal HS width, as well as the occurrence, number, and size of HCs, and the visual rating score of MTA on magnified coronal high-resolution T1-weighted MR images.

The findings of our study indicate that the presence of hippocampal cavity (HC) (especially in the left side) and medial temporal lobe atrophy in demented patients was significantly higher in comparison with non-demented elderly subjects ( P ≤ 0.05). There was a significant relationship between MTA and HS width ( P = 0.003, r = 0.00323), and it also had a trend to be significant with size of HCs ( P = 0.08, r = 0.00314). A correlation between MTA and number of HCs was not detected.

HS width is associated with MTA in patients with AD. It may serve as a measure to evaluate MTA for identifying individuals at particularly high risk for Alzheimer progression, and could be employed for selecting subjects for clinical trials or for treatment decisions.