Quantitative susceptibility mapping (QSM) may help monitor iron levels in the brain of patients with multiple sclerosis, identifying patients at higher risk of developing physical disability, according to a study published in the journal Radiology.
Researchers from the University at Buffalo in New York performed a prospective study to assess the relationship between susceptibility and clinical disability in this patient group.
A total of 600 patients with MS participated in the study; 452 subjects had relapsing-remitting MS and 148 had secondary progressive MS. There were also 250 age- and sex-matched control subjects. All underwent MRI imaging of the brain. “Brain atrophy takes a long time to see,” lead author Robert Zivadinov, MD, Ph.D., professor of neurology at the Jacobs School of Medicine and Biomedical Sciences at the University at Buffalo said in a news release. “We need an earlier measure of who will develop MS-related disability.”
The results showed patients with MS presented with lower thalamic susceptibility (27.5 ppb versus 21.1 ppb) and higher susceptibility of basal ganglia (62 ppb versus 54.8 ppb). Lower thalamic susceptibility was associated with longer disease duration, higher degree of disability, and secondary progressive course. Higher susceptibility of the globus pallidus was associated with higher disability. Lower thalamic susceptibility and higher susceptibility of the globus pallidus remained associated with clinical disability after correction for each individual structural volume in voxelwise analysis.
“In this large cohort of MS patients and healthy controls, we have reported, for the first time, iron increasing in the basal ganglia but decreasing in thalamic structures,” Zivadinov said in the release. “Iron depletion or increase in several structures of the brain is an independent predictor of disability related to MS.”
The researchers concluded that the findings suggest that altered deep gray matter iron is associated with the evolution of MS and disability accrual, independent of tissue atrophy.
“Susceptibility is an interesting imaging marker of disease severity that can predict which patients are at severe risk of progressing,” Zivadinov said. “To be able to act against changes in susceptibility would be extremely beneficial.”