Spinal Cord Grey Matter Atrophy Has Greatest Clinical Impact in MS

Researchers have reported a strong relationship between spinal cord gray matter atrophy with disability and multiple sclerosis (MS) disease type, which they said was much stronger than the relationship for any known cortical gray or white matter metric.

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

“This study was driven by the clinical observation that MS progression manifests as a progressive myelopathy in the majority of patients,” Regina Schlaeger, MD, study investigator from the department of neurology at the University of California, San Francisco, told Neurology Advisor. “Our finding that the spinal cord gray matter was, among other conventional MRI metrics, most relevant in explaining disability was rather unexpected.”

For the study, Dr. Schlaeger and colleagues enrolled 142 patients with MS (age 25-75 years; 60.5% women) and 20 controls and scanned them with 3T MRI. The researchers acquired axial 2D phase sensitive inversion recovery (PSIR) images at disc levels C2/3, C3/4, T8/9 and T9/10. They segmented total cord areas (TCA) semi-automatically and spinal cord gray matter manually, and determined between group differences in areas with age and sex as covariates.

Compared with controls, cervical and thoracic spinal cord relapsing MS patients had smaller gray matter areas (P<.001 at C2/3; P=.003 at T8/9; P=.011 at T9/10), although there were no significant differences in either spinal cord white matter area or TCA. Smaller gray matter areas were reported in progressive MS patients vs. relapsing MS patients (P<.001 at all levels), as were smaller TCAs (P<.001 at C2/3, C3/4 and T8/9; P=.004 at T9/10).

Multivariable model results demonstrated the strongest correlation between cervical spinal cord gray matter area and Expanded Disability Status Scale (EDSS), followed by thoracic spinal cord gray matter area and brain gray matter volume.

In addition, researchers reported the following areas under the ROC curve for the prediction of a progressive course based on logistic models:

• Brain gray matter volume: 0.68
• Cervical gray matter area: 0.84
• Cervical, thoracic gray matter areas and brain gray matter volume as predictors: 0.87

“Traditionally, spinal cord atrophy is thought to be mostly driven by axonal (white matter) loss. We found a preferential reduction in spinal cord gray matter in progressive patients and, moreover, a subtle but selective gray matter atrophy in relapsing patients,” Dr. Schlaeger said. “The cervical spinal cord gray matter area was strongly associated with disability (EDSS) and progressive phenotype, indicating that spinal cord gray matter atrophy is indeed clinically relevant. However, the validity of spinal cord gray matter assessments as a biomarker of progression needs to be further determined in longitudinal studies.”

For more coverage of ECTRIMS 2015, go here.

Reference

1. Schlaeger R et al. Abstract 208. Presented at: The European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) Congress; Oct. 7-10, 2015; Barcelona.