ABSTRACT
<p><b>OBJECTIVE</b>To summarize the main findings seen on conventional and advanced magnetic resonance imaging (MRI) used to assess gray matter (GM) involvement in patients with multiple sclerosis (MS).</p><p><b>DATA SOURCES</b>The data used in this review were obtained mainly from studies reported in the PubMed database using the terms of multiple sclerosis, gray matter, magnetic resonance imaging.</p><p><b>STUDY SELECTION</b>Relevant literatures on studies of GM involvement in MS patients were identified, retrieved and reviewed.</p><p><b>RESULTS</b>MS is the most common chronic, disabling central nervous system disease in young adults. Although traditional thinking has considered MS to be a chronic inflammatory demyelinating condition affecting solely the white matter (WM) of the central nervous system, over the last few years it has been shown that GM pathology is also common and extensive. GM demyelinating lesions can not only be found in the cerebral cortex but also in the deep gray nuclei. Apart from focal demyelinated lesions, diffuse neuronal loss and atrophy is also present in the GM of MS patients.</p><p><b>CONCLUSIONS</b>The widespread use of conventional and quantitative MRI based techniques in MS has led to an improved understanding of the mechanisms underlying the inflammatory and neurodegenerative processes of the disease. However, more researches are needed to unravel GM pathology in MS patients, which at present remains enigmatic.</p>