An abnormal periventricular magnetization transfer ratio gradient occurs early in multiple sclerosis

Area of Science:

• Neuroimaging
• Neurology
• Biomedical Engineering

Background:

• Established multiple sclerosis (MS) exhibits tissue abnormalities near lateral ventricles, assessed by magnetization transfer ratio (MTR).
• The presence and significance of these MTR changes in early MS stages remain unclear.

Purpose of the Study:

• To investigate if MTR abnormalities are present in the earliest clinical stages of MS.
• To determine if these changes occur independently of white matter lesions.
• To assess their association with subsequent conversion to clinically definite MS and disability.

Main Methods:

• MRI scans were performed on 71 subjects with clinically isolated optic neuritis and 37 healthy controls.
• Magnetization transfer ratio (MTR) gradients were measured in normal-appearing white matter at varying distances from lateral ventricles.
• Subjects were followed clinically for 2 and 5 years.

Main Results:

• Optic neuritis subjects showed an abnormal MTR gradient near ventricles compared to controls.
• A steeper MTR gradient predicted conversion to clinically definite MS within 2 years, independent of T2 lesions.
• MTR gradients correlated with disability scores at 5 years, though lesion measures became stronger predictors over time.

Conclusions:

• An abnormal periventricular MTR gradient is an early indicator in MS, detectable even before significant lesions form.
• This MTR abnormality is clinically relevant, predicting disease conversion and disability.
• The findings suggest MTR changes may arise from mechanisms partly independent of lesion formation.