What is the initial treatment approach for a patient with suspected or confirmed multiple sclerosis (MS) shown on magnetic resonance imaging (MRI)?

Initial Treatment Approach for Multiple Sclerosis on MRI

For a patient with suspected or confirmed MS on MRI, immediately initiate disease-modifying therapy (DMT) after confirming the diagnosis meets McDonald criteria, prioritizing high-efficacy agents in patients with high lesion burden, infratentorial lesions, or contrast-enhancing lesions. 1, 2, 3

Diagnostic Confirmation and Baseline Assessment

Before initiating treatment, confirm the diagnosis using standardized MRI protocols:

• Perform brain MRI with T2-weighted, T2-FLAIR, and gadolinium-enhanced T1-weighted sequences to establish dissemination in space (DIS) and dissemination in time (DIT) per McDonald criteria 1
• Include spinal cord MRI to assess baseline disease burden and evaluate for dissemination in space, which informs long-term prognosis and treatment escalation decisions 2
• Use MRI systems with field strength of 0.5T or higher with 5mm slice thickness for accurate lesion detection 1
• Ensure all subsequent scans are performed on the same MRI system using identical imaging protocols to allow accurate comparison 1, 3

Risk Stratification for Treatment Selection

The presence of specific MRI features dictates treatment urgency and intensity:

High-Risk Features Requiring Aggressive Treatment 1, 2

• At least one infratentorial lesion (brainstem or cerebellar) - associated with elevated conversion rate to definite MS and increased disability accumulation 1
• Spinal cord lesions - predict higher risk of disability progression 1, 2
• Contrast-enhancing lesions - indicate acute inflammatory activity requiring immediate intervention 1, 2
• High T2 lesion burden (>9 lesions) - strongly associated with conversion to definite MS and disability accumulation 1

Lower-Risk Features 1, 4

• Normal or minimal brain MRI findings - 79% of patients with normal baseline brain MRI do not convert to definite MS after 20 years 1
• Absence of infratentorial and spinal cord lesions - lower risk of rapid disability progression 1

Treatment Initiation Algorithm

For Clinically Isolated Syndrome (CIS) or Radiologically Isolated Syndrome (RIS) 1, 4

• Initiate DMT immediately if high-risk MRI features are present (infratentorial lesions, spinal cord lesions, or contrast enhancement) 1, 2
• For RIS patients, perform follow-up MRI at 3-6 months to detect new lesions before treatment decisions 4
• High-risk RIS patients should undergo more frequent monitoring every 3-4 months and strongly consider early DMT initiation 4

For Relapsing-Remitting MS (RRMS) 2, 3, 5

• Start high-efficacy DMT (such as ocrelizumab 600mg IV every 24 weeks) for patients with active disease demonstrated by new clinical relapse with corresponding MRI findings 2, 5
• Do not delay treatment due to lack of gadolinium enhancement - non-enhancing T2 lesions still represent active MS disease 3
• Two or more new T2 lesions between scans demonstrates ongoing disease activity requiring treatment optimization 3

Post-Treatment MRI Monitoring Protocol

Standardized follow-up is essential to assess treatment response:

Initial Monitoring Phase 2, 3, 4

• First follow-up MRI at 3-6 months after initiating DMT to assess treatment response 2, 3
• Subsequent MRIs every 6 months for the first 1-2 years given documented disease activity 3
• Include contrast-enhanced T1-weighted sequences to detect acute inflammation, though active (new or enlarging) T2 lesions can deliver sufficient information about subclinical disease activity depending on scan interval 1

Long-Term Monitoring 3, 4

• Transition to annual MRI if disease remains stable on treatment 3, 4
• Continue clinical assessments every 6 months minimum 3
• Perform cognitive assessment using Symbol Digit Modalities Test (SDMT) every 6 months 4

Treatment Escalation Criteria

Breakthrough disease activity requires treatment modification:

• One or more relapses with at least one contrast-enhancing lesion indicates suboptimal treatment response 2
• Two or more new T2 lesions between follow-up scans suggests breakthrough disease activity 2, 3
• Escalate to higher-efficacy DMT when these criteria are met 2

Critical Pitfalls to Avoid

• Never delay treatment waiting for gadolinium enhancement - small non-enhancing lesions still represent disease progression 3
• Do not use inconsistent MRI protocols between scans - this prevents accurate comparison of disease activity 1, 3
• Avoid underestimating small lesions - even small non-enhancing lesions count as disease progression in RRMS 3
• Do not rely solely on spinal cord MRI for routine monitoring - brain MRI is more sensitive for detecting disease activity 1, 2
• Never perform cervical spine MRI alone without brain imaging for disease monitoring 2

Special Considerations for Spinal Cord Imaging

While spinal cord assessment is important for baseline evaluation:

• Spinal cord MRI has limited value for routine disease monitoring and should not delay treatment of clinical relapse 2
• Brain MRI is more sensitive than spinal cord imaging for detecting disease activity, particularly contrast-enhancing lesions 1
• Strong relationship exists between new brain lesions and new spinal cord lesions, making serial spinal cord imaging of limited added value 1
• Complete baseline cervical spine MRI to establish disease burden, but prioritize brain imaging for ongoing monitoring 2