Comparing regional brain atrophy in mild cognitive impairment and Alzheimer's disease

Neuroimaging has assumed an active role in the diagnosis of Alzheimer's disease (AD) and other dementias. Structural MRI can estimate changes in specific brain structures relative to normal and pathological aging such as volume, cortical thickness and gray matter density. Several different structural MRI methods can be used to identify neuropathology and point to an early atrophy in medial temporal lobe structures in patients with AD and amnestic mild cognitive impairment, especially in the entorhinal cortex and hippocampus. These alterations in medial temporal lobe structures were also considered evidence for neurodegeneration, even in preclinical AD. However, evaluation in other areas such as ventricular enlargement and precuneus may help the diagnosis, even in the early stages of the disease. Currently, neuroimaging is an excellent tool for increasing diagnostic accuracy, but does not substitute a careful clinical and neuropsychological evaluation. In this article, our objective is to gather information about different structural MRI-based methods that could offer objective measures of brain structures and increase the diagnostic power of mild cognitive impairment and AD.