The usefulness of gadolinium-enhanced images on a follow-up magnetic resonance image in suspected multiple sclerosis.

PURPOSE

Multiple sclerosis diagnostic criteria include the presence of gadolinium-enhancing lesions when determining dissemination in space and time. Gadolinium is expensive, increases scan time and patient discomfort, and can, rarely, cause serious adverse effects. Our objective was to determine the usefulness of including gadolinium-enhanced images as part of a follow-up brain magnetic resonance imaging (MRI) in patients with a clinically isolated syndrome.

METHODS

Consecutive patients seen between 2008 and 2010 with a clinically isolated syndrome suggestive of multiple sclerosis were prospectively enrolled, had a non-gadolinium-enhanced brain MRI, and consented to a follow-up gadolinium-enhanced brain MRI. The primary outcome was a comparison of the number of patients diagnosed with multiple sclerosis compared with the number who would have been diagnosed without the gadolinium-enhanced images.

RESULTS

Twenty-one patients enrolled, and 2 withdrew. Follow-up MRIs were performed a median of 241 days after the initial MRI. Eleven patients met the primary outcome and were diagnosed with multiple sclerosis: 6 as a result of a second clinical attack and 5 by using imaging criteria for dissemination in space and time. If the gadolinium-enhanced images had not been obtained, then there would have been no change in the primary outcome.

CONCLUSIONS

In Canadian centers with similar MRI waiting times to those in our study, the routine use of gadolinium as part of a follow-up MRI in patients with suspected multiple sclerosis may not be clinically useful. Gadolinium-enhanced images could still be obtained on an as-needed basis for specific clinical indications.