The primary objective of this sub-study is to calculate the reproducibility and other technical performance measures of various magnetic resonance imaging (MRI) image analysis algorithms in order to assess their suitability for detecting changes due to multiple sclerosis (MS) in a real-world setting in participants with MS. The secondary objective of this sub-study is to use the primary endpoint results to calibrate measurements across scanners within each MS PATHS center.

Key Inclusion Criteria:

• Participants (or participant's legal representative) has the ability to understand the purpose and risks of the sub-study and provide signed and dated informed consent and authorization to use protected health information (PHI) in accordance with national and l local participant privacy regulations.
• Diagnosis of relapse-onset MS (relapsing-remitting or secondary progressive).
• First MS symptom within the past 1 to 30 years.

Key Exclusion Criteria:

• Initiation of any MS disease-modifying treatment within 4 weeks prior to Visit 1.
• Steroid treatment or suspected MS relapse within 6 weeks prior to Visit 1.

Note: Other protocol specified inclusion and exclusion criteria may apply.

Potential participants will be participants with MS enrolled in Study 888MS001 who have varying levels of disease severity and symptom duration.