Should I order a head computed tomography (CT) or magnetic resonance imaging (MRI) for a patient with no neurological deficits after a fall 2 weeks ago?

Head Imaging After Fall with No Neurological Deficits

For a patient who fell 2 weeks ago with no neurological deficits, no imaging is necessary as neither CT nor MRI is indicated in this clinical scenario.

Rationale for No Imaging Recommendation

Clinical Decision-Making for Head Trauma

• According to the ACR Appropriateness Criteria for Head Trauma (2021), imaging is primarily indicated in the acute setting when there are concerning symptoms or risk factors 1
• For patients with a normal neurological examination and no symptoms after the acute period, routine imaging is not indicated 1
• The absence of neurological deficits 2 weeks after injury strongly suggests no clinically significant intracranial pathology

Evidence Against Routine Imaging

• The diagnostic yield of head imaging in patients without neurological deficits is extremely low 1
• The ACR guidelines indicate that follow-up imaging is primarily warranted when there are:
  • Persistent neurological deficits
  • Clinical deterioration
  • High-risk features (e.g., coagulopathy, advanced age with anticoagulation)

When Imaging Would Be Indicated

Indications for CT

• CT would be indicated in the acute setting (within 24 hours) for patients with:
  • Headache
  • Vomiting
  • Age over 60 years
  • Drug or alcohol intoxication
  • Deficits in short-term memory
  • Physical evidence of trauma above the clavicles
  • Seizure 2

Indications for MRI

• MRI would be indicated for:
  • Persistent unexplained neurological deficits
  • Cognitive symptoms that persist beyond the expected recovery period
  • When there is suspicion for diffuse axonal injury not visible on CT 1, 3

Modality Selection if Imaging Were Needed

If the clinical situation changed and imaging became necessary:

• CT Head Without Contrast:

  • First-line for acute evaluation (within first 24-72 hours)
  • Rapid, accessible, excellent for detecting acute hemorrhage
  • Less sensitive for small contusions and axonal injuries 1

• MRI Brain Without Contrast:

  • Superior for subacute/chronic evaluation (>72 hours post-injury)
  • More sensitive for detecting small cortical contusions, subdural hematomas, and diffuse axonal injury
  • Better for evaluating persistent symptoms when CT is negative 1, 3

Common Pitfalls to Avoid

• Unnecessary imaging exposes patients to radiation (CT) or increased healthcare costs (MRI) without clinical benefit
• Incidental findings on imaging may lead to additional unnecessary testing and patient anxiety
• Over-reliance on imaging rather than clinical assessment can divert attention from appropriate symptom management

In this case, with no neurological deficits 2 weeks after a fall, clinical observation is the most appropriate approach, with imaging reserved only if new symptoms or neurological deficits develop.