Since all enhancing lesions were associated with new lesions on unenhanced imaging and progression was only evident in 24% of patients with relapsing-remitting multiple sclerosis (RRMS), it is reasonable to consider reserving contrast for only those patients with evidence of progression on non-contrast MR images. This according to a recent retrospective image-analysis study that aimed to determine whether contrast could be reserved for only those patients who show new MS lesions on follow-up examinations. Researchers retrospectively reviewed brain MRIs of 138 patients. To increase the sensitivity, they used a previously described computerized image-comparison software to evaluate the stability or progression of MS white matter lesions in non-contrast FLAIR sequences. They found:

• 33 scans showed an increase in white matter lesion burden.
• Among those 33 patients, 14 examinations also demonstrated enhancing new lesions.
• While a single example of enhancement of a pre-existing white matter lesion that appeared unchanged in size was found, that same examination showed an overall increase in lesion burden with enhancement of other, new lesions.
• Thus, all patients with enhancing lesions had evidence of progression on their non-contrast imaging.