What is the recommended initial brain MRI protocol, with or without contrast (magnetic resonance imaging), for a patient with post-concussion syndrome?

Brain MRI Protocol for Post-Concussion Syndrome

For patients with post-concussion syndrome, brain MRI without IV contrast is the recommended initial imaging protocol. 1

Rationale for MRI Without Contrast

The ACR Appropriateness Criteria for head trauma explicitly states that brain MRI is the most useful initial imaging for subacute or chronic head trauma when persistent cognitive or neurologic deficits are present, as is the case in post-concussion syndrome (defined as symptoms persisting >3 months). 1

Contrast administration is not necessary for the initial evaluation because:

• MRI without contrast is more sensitive than CT for detecting the subtle findings relevant to post-concussion syndrome, including microbleeds, white matter lesions, focal encephalomalacia, and traumatic axonal injury 1
• The structural lesions being evaluated (microhemorrhages, encephalomalacia, white matter hyperintensities) are visible on non-contrast sequences 2
• There is no relevant literature supporting the routine use of contrast-enhanced brain MRI for post-concussion syndrome evaluation 1

Key MRI Sequences to Include

Your MRI protocol should incorporate:

• Susceptibility-weighted imaging (SWI) or T2*-weighted sequences to detect microhemorrhages, which are found in approximately 1.6% of post-concussion syndrome patients 2
• T2/FLAIR sequences to evaluate white matter hyperintensities, present in approximately 22% of post-concussion syndrome patients (though this rate is similar to age-matched controls) 2
• Standard anatomic sequences to assess for encephalomalacia and atrophy 2

Clinical Context and Expectations

Important caveat: Structural lesions on conventional MRI are rare in post-concussion syndrome. A prospective study of 127 post-concussion syndrome patients found positive structural findings in only 3.1% of cases (microhemorrhages in 1.6%, encephalomalacia in 1.6%). 2 The presence of such lesions actually suggests a more severe form of traumatic brain injury rather than typical post-concussion syndrome. 2

The primary value of MRI in post-concussion syndrome is diagnostic exclusion rather than confirmation—ruling out atrophy, encephalomalacia, and all forms of intracranial hemorrhage that would indicate more severe injury. 2

When Contrast May Be Considered

While not part of the initial protocol, contrast may be appropriate in specific circumstances:

• If initial non-contrast MRI reveals unexpected findings requiring further characterization 1
• If there is clinical suspicion for alternative diagnoses (infection, neoplasm, inflammatory conditions) that would not be typical post-concussion syndrome 1

Common Pitfalls to Avoid

• Do not over-interpret white matter hyperintensities: These are present in approximately 20% of age-matched controls and their presence alone does not confirm or exclude post-concussion syndrome 2
• Do not expect MRI to "prove" post-concussion syndrome: Normal conventional MRI does not exclude the diagnosis, as most patients with genuine post-concussion syndrome have normal structural imaging 1, 2
• Avoid routine contrast administration: This adds cost, time, and potential contrast-related risks without established benefit for typical post-concussion syndrome evaluation 1