Should a patient with balance issues and new onset headaches get a computed tomography (CT) head or magnetic resonance imaging (MRI) head?

Neuroimaging for Balance Issues and New Onset Headaches

This patient requires neuroimaging, and CT head should be obtained first, with MRI brain reserved as a second-line test if CT is unrevealing or if symptoms persist or worsen.

Initial Imaging Decision

Balance issues (dizziness/lack of coordination) combined with new onset headaches are red flag features that significantly increase the likelihood of clinically significant intracranial pathology and warrant neuroimaging. 1

Key Clinical Features Supporting Imaging

The combination of symptoms in this patient includes:

• History of dizziness or lack of coordination - This significantly increases the odds of finding an abnormality on neuroimaging 1
• New onset headache - While evidence is insufficient to make definitive recommendations, new onset headaches increase the likelihood of significant intracranial pathology 1
• Balance issues - These represent neurologic symptoms that elevate concern for structural lesions 2, 3

CT Head as First-Line Imaging

Start with non-contrast CT head as the initial imaging modality. 1

Rationale for CT First

• CT can be performed safely and rapidly in all patients and is the first-line neuroimaging test of choice in acute settings 1
• CT effectively detects clinically significant pathology including hemorrhage, mass effect, hydrocephalus, and large structural lesions 1
• CT and MRI may be equally sensitive for detecting clinically significant pathology, though MRI may identify more clinically insignificant abnormalities 1
• CT is faster and less susceptible to motion artifact compared to MRI, making it practical for initial evaluation 1

What CT Will Detect

Non-contrast CT head effectively identifies:

• Acute intracranial hemorrhage 1, 4
• Mass lesions with significant mass effect 1
• Hydrocephalus 1
• Large territorial infarctions 5

MRI Brain as Second-Line Imaging

If CT is unrevealing and symptoms persist or worsen, proceed to MRI brain without and with contrast. 1, 5

When to Escalate to MRI

MRI should be obtained when:

• Initial CT is normal but clinical suspicion remains high for intracranial pathology 1, 5
• Symptoms persist beyond 24-48 hours despite normal CT 5
• Neurologic deficits worsen or new deficits develop 5

Superior Sensitivity of MRI

• MRI has higher sensitivity for detecting small ischemic infarcts, particularly small cortical infarcts that CT may miss 1, 5
• MRI can identify 70% of strokes that present with altered mental status, which CT may not detect 5
• MRI better characterizes posterior fossa lesions, subtle masses, encephalitis, and inflammatory conditions 1, 4
• MRI provides superior soft tissue detail for evaluating vascular malformations and certain parenchymal lesions 4

Critical Considerations

Red Flags Present in This Case

The patient's presentation includes multiple concerning features:

• Balance issues represent a neurologic symptom that increases likelihood of intracranial pathology 1
• Dizziness/lack of coordination has a positive likelihood ratio for detecting abnormalities on neuroimaging 1
• New onset headache warrants lower threshold for imaging, particularly in older patients 1, 2

Common Pitfalls to Avoid

• Do not skip imaging based on normal neurologic examination alone when red flag symptoms like balance issues are present 1
• Do not order MRI first in the acute setting - CT is faster and equally effective for detecting emergent pathology 1
• Do not assume all abnormalities found are clinically significant - MRI may detect more incidental findings than CT 1

Testing Principles to Follow

Three consensus principles guide this decision 1:

1. Testing should lead to a change in management - Balance issues with headache may indicate treatable pathology
2. This patient is significantly more likely than the general population to have a significant abnormality given the combination of symptoms
3. The presence of neurologic symptoms (balance issues) justifies imaging even if the neurologic examination is normal

Clinical Algorithm

Step 1: Obtain non-contrast CT head immediately 1

Step 2: If CT shows acute pathology (hemorrhage, mass, hydrocephalus), manage accordingly 1

Step 3: If CT is normal but symptoms persist or worsen over 24-48 hours, obtain MRI brain without and with contrast 1, 5

Step 4: If both CT and MRI are normal and symptoms resolve, consider primary headache disorder with vestibular component 1