Differences in microstructural alterations of the hippocampus in Alzheimer disease and idiopathic normal pressure...

Area of Science:

• Neuroimaging
• Neurology
• Medical Diagnostics

Background:

• Alzheimer's disease (AD) and idiopathic normal pressure hydrocephalus (iNPH) can present with similar symptoms in elderly patients.
• Differentiating AD from iNPH using visual MRI measurements is challenging due to enlarged ventricles.
• Diffusion Tensor Imaging (DTI) measures white matter tract integrity via Fractional Anisotropy (FA) and Mean Diffusivity (MD).

Purpose of the Study:

• To investigate hippocampal microstructural integrity changes in iNPH using DTI.
• To determine if DTI can serve as a diagnostic tool to differentiate iNPH from AD.
• To compare DTI findings with volumetric assessments in these conditions.

Main Methods:

• Recruited 43 participants: 15 healthy controls, 15 AD patients, and 13 iNPH patients.
• Measured FA and MD values in hippocampal subdivisions (head, body, tail) using the region-of-interest method.
• Included clinical history, neurological examination, and neuropsychological assessments.

Main Results:

• FA values were lowest in AD, followed by iNPH, then controls.
• MD values were highest in AD, followed by iNPH, then controls.
• These DTI alterations were consistent across hippocampal subdivisions; hippocampal volume did not differ between iNPH and AD patients.

Conclusions:

• Hippocampal microstructural alterations detected by DTI are more sensitive indicators than volumetric changes in AD and iNPH.
• DTI analysis shows promise as a valuable tool for distinguishing between AD and iNPH.
• This neuroimaging technique may aid in clinical diagnosis and management decisions.