MRI Lesions for MS Debate: Why the Answer is 'No'

Magnetic resonance imaging (MRI) can be used to identify lesions in the central nervous system in patients with multiple sclerosis (MS), but not all patients with active disease have identifiable lesions, and researchers are mixed over the extent to which lesions can be used as a marker for MS disease activity.

In a session at the 31st Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS 2015) in Barcelona, Spain, researchers presented opposing viewpoints on the question of “Should MRI be the primary endpoint of phase III trials in MS?”

Brian G. Weinshenker, MD, FRCP(C), from the Mayo Clinic, elaborated on why physicians should proceed with caution with MRI lesions. One study referenced by Weinshenker included 208 individuals with MS. After using MRI lesions to draw conclusions about disease severity and risk of progression, the researchers reported significant variations within the results. Ultimately, they concluded that there was no correlation between the practice and predicting outcomes. Another trial determined that there was no independent contribution in T1 lesions to predicting on-trial relapses.

“If MRI is so good, why couldn’t others predict relapses in the placebo group?” Weinshenker asked. He added that if MRI lesions were so predictive then they would work the majority, if not all, of the time. However, as seen with the studies he cited, outcomes varied substantially.

“It may not be equally informative in all patients,” Weinshenker noted, which adds to the point that the strategy can’t be used as a primary endpoint.

“MRI clearly adds information for sensitivity, but atrophy is probably the most applicable measure,” Weinshenker said. He also mentioned that arguments in favor of MRI have group data backing it up, but more specific information is not available. He also pointed out several disadvantages associated with MRI lesions that raise red flags, including:

• Technical consideration (such as population and duration)
• Limited current multidimensionality
• Conflicting evidence coordinated with relapses
• Variability of treatment effects
• Uncertain long-term relevance
• Lack of disease specificity, especially atrophy

For these reasons and more, Weinshenker said he thinks that MRI is not ready to be used as a primary endpoint yet.

As researchers continue to study this topic, focusing on long-term outcomes could help provide answers to some of the remaining questions in this field. Most clinical trials do not typically exceed three years in duration, so although it would be challenging, long-term follow-up and real-world studies may be just what’s missing.

Get the opposite side of the argument: MRI Lesions for MS Debate: Why the Answer is ‘Yes’