A study led by researchers at the University of Buffalo has shown that an advanced MRI technique can help to identify patients with multiple sclerosis (MS) who are at an increased risk of developing a physical disability.
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Lead author Robert Zivadinov hopes the technique, called “quantitative susceptibility mapping,” will provide a more accurate way of identifying those at risk of cognitive and physical decline than the method that is currently used.
The gold standard currently used to predict this decline is the presence of brain atrophy. However, Zivadinov says brain atrophy is difficult to see and that an earlier measure of who will develop MS-related disability is needed.
In patients with MS, three key central nervous system components are attacked; namely nerve fibers, myelin (the protective sheath that forms around the axon of nerve cells) and Schwann cells (that produce myelin). Symptoms include pain, spasticity and weakness and many patients with disease progression develop severe disability.
Studies have recently shown that MRI assessment of iron levels in the brain may provide a promising measure of the brain changes that occur in MS as the disease progresses.
Iron is required for a range of functions within brain cells, including myelination, and both increased and decreased iron concentrations can be damaging.
It is known that there is more iron in the deep gray matter structures in MS patients, but also we’ve seen in recent literature that there are regions where we find less iron in the brains of these patients.”
Robert Zivadinov, Lead Author
Using the technique, Zivadinov and his team compared iron levels in the brains of 600 MS patients (452 with early-stage disease and 148 with disease progression) to those of 250 healthy controls.
Brain regions with a higher iron concentration would show a higher magnetic susceptibility, while those with a lower concentration would show a lower susceptibility.
Compared with the control group, patients with MS had higher levels of iron in the basal ganglia (gray matter structures involved in movement) and lower levels in the thalamus (a gray matter structure involved in the processing of sensory input).
As reported in the journal Radiology, a lower iron concentration in the thalamus and higher concentration in the basal ganglia in patients with MS was associated with longer duration of disease, a greater degree of disability and disease progression.
Zivadinov says this is the first time a study has shown increasing iron levels in the basal ganglia, but decreasing levels in the thalamic structures of MS patients.
“Iron depletion or increase in several structures of the brain is an independent predictor of disability related to MS, ” he states, adding that the findings point to a potential role for quantitative susceptibility mapping in clinical trials of promising new drugs.
Susceptibility is an interesting imaging marker of disease severity that can predict which patients are at severe risk of progressing. To be able to act against changes in susceptibility would be extremely beneficial.”
Robert Zivadinov, Lead Author