Grey, White Matter Ratio and Disability in Relapsing-Remitting Multiple Sclerosis

Results of a study suggest that grey/white matter ratio is associated with disability progression and secondary progression conversion among patients with newly diagnosed relapsing-remitting multiple sclerosis (RRMS).

These data were presented at the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) Congress in Barcelona.

For the study, Marcello Moccia, MD, resident in neurology and PhD candidate at the University of Naples Federico II, and colleagues investigated possible predictors of long-term MS evolution to perform a complete clinical profile of MS patients since the time of diagnosis.

“In particular, previous MRI studies focused on grey matter alone, whereas MS is well-known to affect both grey and white matter,” Dr. Moccia told Neurology Advisor. “Therefore, we decided to focus on this novel MRI measure — the ratio between grey and white matter volumes — that is possibly an estimate of the heterogeneous pathological mechanisms underlining MS.”

The retrospective, longitudinal study involved 134 patients with RRMS who received MRI evaluation at the time of diagnosis with acquisition of T1-weighted volumes for segmentation purposes.

During follow-up (mean, 10.1 ± 1.8 years), 40.3% of patients reached 4.0 on the Expanded Disability Status Scale (EDSS). Compared with patients not reaching EDSS 4.0, those who did experienced a reduction in grey/white matter ratio (1.270 ± 0.156 vs. 1.343 ± 0.185; P<.001). In addition, 29 patients converted to secondary progression, which led to a reduction in grey/white matter compared with those who did not convert to secondary progression (1.241 ± 0.149 vs. 1.334 ± 0.179; P<.001)

“This is possibly due not only to a more pronounced grey matter atrophy in subjects at risk of secondary progression, but also to a relative sparing of the white matter, which conversely is more frequently affected in patients with a more definite relapsing-remitting course,” Dr. Moccia said.

Additional data revealed that patients with a higher grey/white matter ratio at diagnosis had a 90% reduced rate of reaching EDSS 4.0 (P=.004) and of SP conversion (P=.004) vs. those with a lower grey/white matter ratio. Researchers also found no association between grey/white matter ratio and the annualized relapse rate or the rate of experiencing a relapse.

Dr. Moccia said that clinical profiling of MS patients is of utmost importance and has to be performed during the diagnosis.

“MRI evaluation needs to consider both grey and white matter, possibly by estimating the ratio between their volumes,” he said. “However, MRI is only a part of the required evaluation and there are different factors to be considered, such as cognitive dysfunctions, which we recently found to be associated with the 10-year risk of MS progression, and biomarkers (i.e., uric acid, an indicator of oxidative stress), which we also found predicted disability progression.”

He added that the current availability of different drugs with variable efficacy and safety deserves an accurate profiling for MS patients to define those more at risk for disability progression and requiring a more aggressive therapeutic approach.

“Therefore, MS specialists need to estimate the risk of MS progression since the time of diagnosis to obtain the highest therapeutic success,” he said.

For more coverage of ECTRIMS 2015, go here.

Reference

1. Moccia M et al. Abstract P430. Presented at: The European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) Congress; Oct. 7-10, 2015; Barcelona.