Longitudinal analysis of new multiple sclerosis lesions with magnetization transfer and diffusion tensor imaging

Area of Science:

• Neuroimaging
• Radiology
• Medical Physics

Background:

• Multiple sclerosis (MS) lesion detection and monitoring are crucial for patient management.
• Conventional MRI has limitations in early lesion detection and tracking disease progression.
• Diffusion tensor imaging (DTI) offers insights into white matter microstructure but may not capture early pathological changes.

Purpose of the Study:

• To evaluate the potential of magnetization transfer imaging (MTI) and DTI for detecting new MS lesions and assessing their evolution.
• To compare the sensitivity of MTI and DTI in identifying pre-lesional changes in MS patients.
• To determine if MTI can detect MS lesions earlier than conventional MRI.

Main Methods:

• Nineteen MS patients underwent serial 1.5T MRI, MTI (balanced steady-state free precession, bSSFP), and DTI over 24 months.
• MTI provided magnetization transfer ratio (MTR) and quantitative MTI (qMT) parameters (F, kf, T1/T2).
• DTI yielded fractional anisotropy (FA) and diffusivity measures (MD, AD, RD).

Main Results:

• Newly detected MS lesions showed reduced MTR/qMT parameters and prolonged T1/T2, alongside reduced FA and increased diffusivity.
• Significant MTR and qMT changes were observed 2-4 months before lesion appearance on MRI.
• DTI did not reveal significant pre-lesional changes; some parameter reversals were noted post-lesion detection.

Conclusions:

• MTI, particularly qMT parameters, is more sensitive than DTI for detecting early MS lesions and assessing their evolution.
• bSSFP-based MTI can detect MS tissue changes 2-4 months earlier than conventional MRI.
• MTI enhances longitudinal lesion assessment, potentially enabling earlier clinical decisions and improved treatment monitoring in MS.