Measurement of spinal cord area in clinically isolated syndromes suggestive of multiple sclerosis

Atrophy of the spinal cord is known to occur in multiple sclerosis but the cause and the timing of its onset are not clear. Recent evidence suggests t hat atrophy may start to occur early in the disease. The aim was to determi ne whether atrophy of the spinal cord could be detected in vivo using MRI t echniques, in patients presenting with a clinically isolated syndrome, whic h in many cases is the earliest clinical stage of multiple sclerosis. The cross sectional area of the spinal cord was measured in 43 patients pre senting with a clinically isolated syndrome and 15 matched controls. T2 wei ghted imaging of the brain was also performed to determine the number and v olume of high signal lesions consistent with disseminated demyelination. Bo th patients and controls were restudied after 1 year. The spinal cord area was significantly smaller in the 74% of patients with an abnormal brain MRI at presentation than in controls (mean areas 73.9 mm( 2) and 78.1 mm(2) respectively, p=0.03). No significant difference was foun d in the spinal cord area between controls and patients with normal baselin e brain imaging. The annual rate of change in patients did not differ signi ficantly from controls. In conclusion, the finding of a smaller cord area in the subgroup of patien ts with clinically isolated syndrome with the highest risk of developing mu ltiple sclerosis-that is, with an abnormal brain MRI, suggests that atrophy has developed in some patients with multiple sclerosis even before their f irst clinical symptoms. However, the lack of a detectable change in cord ar ea over 1 year of follow up contrasts strikingly with the results of an ear lier study of patients with relapsing-remitting multiple sclerosis, suggest ing that the rate of atrophy increases as the disease becomes more establis hed.