What clinical signs and symptoms prompt referral for an MRI to test for Multiple Sclerosis (MS)?

Clinical Signs and Symptoms Prompting MRI Referral for Multiple Sclerosis

Refer patients for MRI when they present with a first acute or subacute neurological episode (clinically isolated syndrome) suggesting inflammatory demyelination, particularly optic neuritis, partial myelitis, brainstem syndromes, or sensory disturbances developing over several days in young adults aged 20-30 years. 1, 2

Key Clinical Presentations Requiring MRI Evaluation

Relapsing-Remitting Pattern

• Unilateral optic neuritis presenting with visual impairment, scotoma, red-green color desaturation, and pain with eye movement is one of the most common presentations (20-31% of cases) and warrants immediate MRI referral 1, 2
• Partial myelitis with sensory disturbances or motor weakness localized to the spinal cord requires both brain and spinal cord MRI to rule out alternative pathology 1
• Brainstem syndromes such as internuclear ophthalmoplegia, diplopia, vertigo, or facial numbness developing over days should prompt MRI evaluation 1, 2
• Sensory disturbances including numbness, tingling, or paresthesias in limbs or trunk that are subacute in onset 2

Progressive Neurological Symptoms

• Insidious progressive neurological deterioration over at least one year without clear relapses suggests primary progressive MS and requires MRI with specific attention to spinal cord imaging 1
• Progressive gait difficulty, weakness, or coordination problems developing gradually over months to years 1

Critical Clinical Features That Strengthen MRI Indication

Patient Demographics and History

• Young adults (mean age 20-30 years) presenting with neurological symptoms have higher pre-test probability 2
• Female patients (female-to-male ratio nearly 3:1) with compatible symptoms 2
• History of prior neurological episode that resolved spontaneously, followed by new symptoms, demonstrates dissemination in time clinically 3

Symptom Characteristics

• Symptoms developing over several days (not hyperacute like stroke, not chronic like tumor) 2
• Spontaneous recovery from initial episode followed by new symptoms supports relapsing-remitting pattern 3
• Symptoms that are multifocal or suggest involvement of different CNS regions 4

When to Include Spinal Cord MRI

Order whole spinal cord MRI (cervical and thoracic) in addition to brain MRI when: 1, 3

• Clinical features are localized to the spinal cord (to rule out compression, tumor, or neuromyelitis optica)
• Brain MRI does not fulfill dissemination in space criteria
• Presenting symptoms include myelopathy, sensory level, or bladder/bowel dysfunction
• Approximately 40% of spinal cord lesions occur in the thoracolumbar region, so imaging the entire cord is essential 1

Red Flags Requiring Urgent MRI to Exclude MS Mimics

Atypical Features Suggesting Alternative Diagnoses

• Persistent gadolinium enhancement >3 months, lesions with mass effect, or meningeal enhancement suggest disorders other than MS 4, 5
• Encephalopathy or altered consciousness at presentation suggests acute disseminated encephalomyelitis (ADEM), particularly in children 3
• Severe bilateral optic neuritis or longitudinally extensive transverse myelitis (≥3 vertebral segments) should prompt testing for neuromyelitis optica spectrum disorder 1, 3

Clinical Context Requiring Careful Evaluation

• Patients with systemic autoimmune disease, vascular risk factors, or infectious exposures need MRI to distinguish MS from vasculitis, small vessel disease, or infectious etiologies 5
• Age >50 years at onset or atypical symptom progression warrants MRI with attention to MS mimics 5

Common Pitfalls to Avoid

• Do not diagnose MS based solely on MRI findings without at least one clinical event consistent with acute demyelination—this is a cornerstone requirement 1
• Do not assume all white matter lesions are demyelinating; carefully evaluate for vascular disease, migraine-related changes, or other etiologies 3, 5
• Do not skip antibody testing for aquaporin-4 (AQP4) and MOG antibodies when MRI is ordered, as neuromyelitis optica spectrum disorder and MOG-antibody disease require different treatment and can be worsened by MS therapies 3
• Do not order MRI for non-specific symptoms like isolated fatigue, headache, or chronic pain without objective neurological findings 4

Specific MRI Protocol Requirements

When ordering MRI for suspected MS, specify: 6

• Brain MRI with gadolinium including 3D T1-weighted, 3D T2-FLAIR, 3D T2-weighted, post-gadolinium T1-weighted, and diffusion-weighted sequences
• Spinal cord MRI (when indicated) with sagittal T1-weighted, STIR or phase-sensitive inversion recovery, and axial T2-weighted imaging through suspicious lesions
• Provide clinical question and relevant history on the requisition to ensure appropriate protocol selection 6