Serial MRI in Epidemiology: Seasonal Occurrence of New MS Lesions

Dominik S. Meier¹, Charles R.G. Guttmann¹

The use of serial MRI for studies of epidemiological scope is explored on the example of measuring seasonal variation of multiple sclerosis (MS) disease activity. A seasonality of MS disease activity is suggested from clinical and immunological variables, but MRI findings thus far remain controversial. New T2 lesion occurrence and contrast-enhancing lesions (CEL) were measured over a one-year period. We observed greater activity/likelihood in spring and summer for new T2 lesions but not CEL. CEL have a brief window of visibility and thus are sensitive to observation bias. The use of new T2 lesions in lieu of CEL holds considerable advantages and should be seriously considered in its application to clinical trials.