Impact of Magnetic Resonance Imaging (MRI) on the Epidemiology of MS

The availability of MRI has turned out to have less impact on the epidemiology of MS than originally expected. Only 3/69 patients diagnosed between 1986 and 1990 in the epidemiologic area of South Lower Saxony (Germany) would have been missed without MRI. However in 18/50 patients the diagnostic classification changed, mostly from possible to probable MS. As we included possible cases from the beginning of our studies, the overall figures remain essentially unchanged. Epidemiologists who excluded possible cases from their surveys may experience more problems with the introduction of MRI.