There are no specific disease-tracking or prognostication biomarkers for ALS. In vivo, human quantitative spinal cord MRI studies in ALS have consistently shown degeneration in the corticospinal tract (CST) and anterior horns.

Major databases, including PubMed, Scopus, etc., were searched for literature published up to August 2023. This review was conducted based on the PRISMA guidelines, and the study quality was assessed using the Newcastle-Ottawa Scale (NOS). We calculated pooled Standardized mean differences (SMDs) and 95% CIs for comparative assessment of qMRI parameters in ALS individuals and the healthy controls. We used CMA software to estimate the mean of qMRI parameters for normative values in both ALS and healthy controls. Heterogeneity and publication bias were determined by the I-squared statistic and funnel plots.

We included studies with cervical spinal cord qMRI (e.g., DTI, CSA, 1H-MRS, fMRI) data comparing ALS patients with healthy controls using 1.5T or 3T MRI. We excluded non-original and non-human studies.

Thirty studies, involving 1,817 participants (35.9% female), with 29 having an NOS score of 5 or higher, were included in this systematic review, indicating a high overall quality of data. The SMD analysis showed a significant decrease in CSA along the whole length of cervical cord (C1-C7) (p <0.0001), with a preferential thinning of the cervical enlargement region (C4-C6 region) (p <0.0001), significant decrease in FA (p <0.0001),  particularly FA left lateral corticospinal tract (p <0.0001),  and a significant increase in MD (p <0.0001) in ALS individuals compared to controls.