Investigating the Medial Temporal Lobe in Alzheimer's Disease and Mild Cognitive Impairment, with Turboprop Diffusion Tensor Imaging, MRI-volumetry, and T2-relaxometry

The first neuropathological alterations in Alzheimer's disease (AD) occur in the medial temporal lobes (MTLs), in the entorhinal cortex (EC), perforant pathway (PP), and hippocampus. The purpose of this study was to investigate the microstructural integrity, size, and T-2-relaxation times of MTL structures in patients with AD and mild cognitive impairment (MCI), using MRI techniques that are immune to magnetic field inhomogeneities. Turboprop-DTI and high-resolution anatomical MRI data were obtained on AD and MCI patients, and healthy controls. Significant AD-related changes were detected in more MTL structures of AD patients by means of Turboprop-DTI than with any other technique used. Mean diffusivity and T-2-relaxation times of specific MTL structures increased in both the MCI and AD cohorts when compared to normal controls. Therefore, Turboprop-DTI and T-2-relaxometry may be valuable non-invasive tools in the investigation of the early AD-related neuropathological alterations.