Present and Future of Ultra-High Field MRI in Neurodegenerative Disorders.

Abstract

With a high signal-to-noise ratio, unparalleled spatial resolution, and improved contrasts, ultra-high field MR (≥ 7T) has great potential in depicting the normal radiological anatomy of smaller structures in the brain and can also provide more information about morphological, quantitative, and metabolic changes associated with a wide range of brain disorders. By focusing attention on specific brain regions believed to be associated with early pathological change, or by more closely inspecting recognized foci of brain pathology, ultra-high field MR can improve the accuracy and sensitivity of neuroimaging. This article reviews recent studies at ultra-high field about Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). The research on AD has mainly focused on detecting the thinning of hippocampal layers and the susceptibility effect supposed to be related to beta-amyloid deposition. In patients with PD, atypical parkinsonisms and subjects at risk of developing motor symptoms of Parkinson's disease, the main aim was to detect changes in the substantia nigra, probably related to increased iron deposition. In patients with ALS, both brain and spinal cord were investigated, with the aim of finding changes in the primary motor cortex and corticospinal tract which reflect neurodegeneration and neuroinflammation. Ultra-high field MR was shown to be useful for detecting subtle brain changes in patients with AD, and possible new diagnostic biomarkers in patients with PD and ALS were discovered. The ability of 7T MR to provide prognostic biomarkers in subjects at risk for developing synucleinopathies is currently under evaluation.