Imaging multiple sclerosis and other neurodegenerative diseases

Abstract

Although the prevalence of neurodegenerative diseases is increasing as a consequence of the growing aging population, the exact pathophysiological mechanisms leading to these diseases remains obscure. Multiple sclerosis (MS), an autoimmune disease of the central nervous system and the most frequent cause of disability among young people after traumatic brain injury, is characterized by inflammatory/demyelinating and neurodegenerative processes that occurr earlier in life. The ability to make an early diagnosis of MS with the support of conventional MRI techniques, provides the opportunity to study neurodegeneration and the underlying pathophysiological processes in earlier stages than in classical neurodegenerative diseases. This review summarizes mechanisms of neurodegeneration common to MS and to Alzheimer disease, Parkinson disease, and amiotrophic lateral sclerosis, and provides a brief overview of the neuroimaging studies employing MRI and PET techniques to investigate and monitor neurodegeneration in both MS and classical neurodegenerative diseases.

Keywords: MRI; iron; microglia; multiple sclerosis; neurodegenerative diseases.

Figure 1. Overall brain tractography from a 62 y-old male Parkinson patient (A) and a 61 y-old male healthy control (B). The color code represents fiber direction: blue-inferior to superior, red - left to right, green- anterior to posterior. The 3D view from the superior plane shows a diffuse reduction of white matter fibers in the PD patient compared with the control.

Figure 2. TBSS results and SPM-VBM analysis of cortical brain volume from 15 RR-MS patients and 15 healthy controls displayed on the Montreal Neurological Institute template. Clusters of reduced FA in patients compared with healthy controls are indicated in red. Areas of significant reduction of gray matter volume in patients compared with healthy controls are indicated in green.