Non-Conventional MRI Techniques as an Alternative Role to the Clinical Diagnosis in Alzheimer’s Disease

Abstract

Improved methods for early diagnosis and non-invasive surrogates for the diagnosis of disease severity in Alzheimer’s disease (AD) are becoming the new challenge. Dementia can now be accurately determined through clinical evaluation, cognitive screening, basic laboratory evaluation and structural imaging. Magnetic resonance (MRI) techniques are being evaluated as possible surrogate measures to monitor disease progression. The purpose of this work is to correlate the results of combined advanced MR techniques with neuropsychological performance in order to identify a sensible and sensitive imaging approach to quantify neurodegenerative disease progression. One of the most relevant evidences in our study is the degeneration of the fibers of the corpus callosum in the pathogenesis of cognitive disorders in AD patients, as demonstrated by the relationship between altered neuropsychological tests and reduced FA (Fractional Anisotrophy) values of the corpus callosum in such patients. This data is also integrated by the evidence of anatomic reduction of the total volume of the corpus callosum assessed by FreeSurfer, thus supporting the hypothesis that the “brain disconnects” play a key role in the pathogenesis of AD. Statistical evaluation of regression consisting in the identification of different numerical coefficients that are multiplied by the thickness of the right fusiform value or by the volume of left inferoparietal region and left middle-temporal region, allows us to obtain the predictive numeric value of the related neuropsychological test. Combination of non-conventional magnetic resonance imaging, including morphometry, spectroscopy, MD (mean diffusivity) and FA evaluation, could be an alternative to clinic in the evaluation of neurodegeneration in AD.