Cervical Spinal Cord Magnetization Transfer Ratio and Its Relationship With Clinical Outcomes in Multiple Sclerosis

Area of Science:

• Neuroimaging
• Neurology
• Biomedical Engineering

Background:

• The cervical spinal cord (cSC) plays a crucial role in clinical dysfunction observed in multiple sclerosis (MS).
• Quantitative magnetic resonance imaging (MRI) studies of the cSC in MS are limited.
• Magnetization transfer ratio (MTR) is a sensitive MRI metric for detecting MS-related microstructural changes.

Purpose of the Study:

• To assess MTR in the cSC of individuals with radiologically isolated syndrome (RIS) and MS.
• To investigate the relationship between cSC MTR and clinical outcomes in RIS and MS.

Main Methods:

• MTR data were collected from 52 RIS, 201 relapsing-remitting MS (RRMS), 47 primary progressive MS (PPMS), and 43 control (CON) participants.
• Data were acquired across four sites using 3.0T MRI scanners as part of the Canadian Prospective Cohort Study to Understand Progression in MS (CanProCo).
• MTR was compared between groups in the whole cSC and C2-C4 sub-regions; regression analyses examined associations with EDSS, WST, and MDT.

Main Results:

• MTR was consistently lower in PPMS compared to controls (–5.8% to –3.7%, p ≤ 0.01).
• In PPMS, lower MTR correlated with increased disability (EDSS, WST, MDT; p ≤ 0.04).
• In RRMS, MTR was associated only with EDSS (p ≤ 0.03).

Conclusions:

• Cervical spinal cord MTR is lowest in PPMS within a large cohort of RIS and MS patients.
• MTR is associated with clinical outcomes in established MS but not in RIS.
• cSC MTR provides valuable insights into tissue microstructural integrity and its relevance to clinical disability in MS.