Quantitative susceptibility mapping in multiple sclerosis: A systematic review and meta-analysis.

Area of Science:

• Neuroimaging
• Quantitative Susceptibility Mapping (QSM)
• Multiple Sclerosis (MS)

Background:

• Quantitative susceptibility mapping (QSM) is a non-invasive MRI technique sensitive to iron and myelin content.
• QSM shows promise as a tool for multiple sclerosis (MS) research and clinical practice.

Purpose of the Study:

• To conduct a systematic review and meta-analysis on the application of QSM in multiple sclerosis (MS).

Main Methods:

• Systematic review and meta-analysis of 83 English peer-reviewed studies published up to April 2023.
• Searched five databases, focusing on studies measuring deep grey matter (DGM) QSM values, lesion characteristics, and clinical/histological correlates in MS patients compared to healthy controls (HC).
• Two meta-analyses were performed on DGM susceptibility data; other findings were analyzed descriptively.

Main Results:

• Meta-analyses revealed significantly increased basal ganglia susceptibility (caudate, putamen, globus pallidus) and decreased thalamic susceptibility in MS patients compared to HC.
• Putamen QSM values showed a positive correlation with the Expanded Disability Status Scale (EDSS), indicating a link to disability.
• Histological data suggest iron content drives QSM changes in DGM and rim lesions, while myelin reduction contributes to increased QSM in white matter lesions.

Conclusions:

• Meta-analytic evidence confirms altered DGM susceptibility in MS, with increased basal ganglia and decreased thalamic susceptibility, the latter associated with disability.
• Further research is needed to fully establish the role of QSM in MS for both research and clinical applications.