Subcortical and Cortical Gray Matter Atrophy in a Large Sample of Patients with Clinically Isolated Syndrome and Early Relapsing-Remitting Multiple Sclerosis

Brain atrophy is commonly seen in patients with chronic MS. Here, the authors assessed 212 patients with clinically isolated syndrome and early RRMS for atrophy of gray matter. In both groups the cortex displayed no significant atrophy but the deep gray matter nuclei (caudate, thalamus, globus pallidus, putamen, and hippocampus) showed significant atrophy during the first 4 years of the disease. Deep gray matter atrophy may play a relevant role in patient symptoms and seems to appear and progress from the earliest stages of the disease. BACKGROUND AND PURPOSE: Recent studies have shown that selective regional, but not global, GM atrophy occurs from clinical onset to conversion to clinically definite MS. Our aim was to investigate the difference in the extent of SDGM and cortical atrophy in a large sample of patients with CIS and early RRMS and to explore the relationship between SDGM and cortical atrophy and other MR imaging and clinical outcomes. MATERIALS AND METHODS: Two hundred twelve patients with CIS recruited at the first clinical event (mean age, 29.3 years; median EDSS, 1.5; median disease duration, 3 months) and 177 patients with early RRMS (mean age, 30.7 years; median EDSS, 2.0; median disease duration, 47 months) were imaged on a 1.5T scanner by using a high-resolution 3D T1 spoiled gradient-recalled sequence. Volumetric data for SDGM structures were obtained by using FSL FIRST, while whole-brain, GM, white matter, cortical, and lateral ventricle volumes were estimated by using SIENAX software. Comparisons between the groups were adjusted for age and sex. RESULTS: Patients with early RRMS showed significantly lower SDGM but not cortical volumes compared with patients with CIS. The most apparent SDGM differences were evident in the caudate and thalamus (P < .0001), total SDGM (P = .0001), and globus pallidus (P = .01). Patients with CIS with a median T2 lesion volume >4.49 mL showed lower total SDGM, caudate, thalamus (P < .001), globus pallidus (P = .007), hippocampus (P = .004), and putamen (P = .01) volumes and higher lateral ventricle volume (P = .001) than those with a median T2 lesion volume <4.49 mL. Decreased thalamic volume showed the most consistent relationship with MR imaging outcomes (P < .0001) in patients with CIS. CONCLUSIONS: Significant SDGM, but not cortical, atrophy develops during the first 4 years of the RRMS. GM atrophy is relevant for disease progression from the earliest clinical stages.