T2 relaxation time analysis in patients with multiple sclerosis: correlation with magnetization transfer ratio

Area of Science:

• Neuroimaging
• Magnetic Resonance Imaging (MRI)
• White Matter Diseases

Background:

• Multiple sclerosis (MS) involves complex histopathological changes in white matter.
• Understanding these changes requires advanced MRI techniques to analyze tissue properties.

Purpose of the Study:

• To measure T2 relaxation times and correlate them with Magnetization Transfer Ratio (MTR) in MS patients.
• To investigate histopathological changes in MS lesions and normal-appearing white matter (NAWM).

Main Methods:

• Performed T2 relaxation time and MTR measurements in 13 MS patients and 10 healthy volunteers.
• Analyzed MS plaques, NAWM, dirty white matter (DWM), and normal white matter (NWM).
• Utilized biexponential T2 relaxation analysis and linear regression to assess correlations.

Main Results:

• Biexponential T2 relaxation was more frequent in "black-hole" lesions and enhancing plaques.
• Strong linear correlations between MTR and monoexponential T2 were observed in DWM, black-hole, and isointense lesions.
• Correlation weakened in areas with coexisting inflammation and demyelination, and was non-significant in NAWM and NWM.

Conclusions:

• Biexponential T2 relaxation is indicative of severe demyelination and axonal loss in MS lesions.
• MTR and T2 relaxation times are sensitive to inflammation and demyelination, but their relationship is complex.
• These MRI parameters offer insights into the diverse pathological processes in MS white matter.