Pediatric Imaging

Which Imaging Study for a Child with Severe Head Trauma and a Low GCS?

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Which Imaging Study for a Child with Severe Head Trauma and a Low GCS?

It’s 2 a.m. in the emergency department, and a 7-year-old arrives by ambulance after falling from a second-story window. The child is lethargic, moaning but not verbalizing, and withdraws to painful stimuli. Their Glasgow Coma Scale (GCS) score is 9. This is a clear case of moderate-to-severe acute blunt head trauma, and the immediate clinical question is not if you should image, but what to order first to guide life-saving intervention. For this high-acuity presentation, the American College of Radiology (ACR) Appropriateness Criteria designates one study as the clear first step. According to the ACR, CT head without IV contrast is Usually appropriate for the initial evaluation.

Who Fits This Clinical Scenario?

This guidance applies specifically to a child presenting with moderate or severe acute blunt head trauma, defined by a Glasgow Coma Scale (GCS) score of 13 or less. The GCS is a critical initial assessment, and a score in this range indicates a significant alteration in consciousness, from confusion and lethargy (GCS 9-13) to stupor or coma (GCS less than 9). This workflow is intended for the immediate, initial imaging decision after the traumatic event.

It is crucial to distinguish this scenario from others that may appear similar but follow different diagnostic pathways:

  • Minor Head Trauma (GCS 14-15): If the child has a GCS of 14 or 15, they fall into the minor head trauma category. The decision to image is then guided by clinical decision rules like the Pediatric Emergency Care Applied Research Network (PECARN) criteria, which stratify patients into very-low, intermediate, or high-risk groups for clinically important brain injury.
  • Suspected Abusive Head Trauma: This guideline explicitly excludes cases where non-accidental trauma is suspected. The imaging workup for abusive head trauma is more extensive and follows a distinct protocol, often involving a skeletal survey and specific MRI sequences.
  • Subacute or Chronic Symptoms: If the patient presents days or weeks after an injury with new or worsening cognitive or neurologic signs, the clinical question and imaging priorities shift. This constitutes a different clinical scenario where MRI may play a larger role.

What Diagnoses Are You Working Up in This Scenario?

In a child with a GCS of 13 or less after blunt trauma, the primary goal of imaging is to rapidly identify life-threatening intracranial injuries that may require immediate neurosurgical intervention. The differential diagnosis is focused on traumatic brain injuries (TBIs) that cause mass effect, herniation, or significant neuronal damage.

Epidural Hematoma (EDH): This is a classic, emergent concern, often resulting from a skull fracture that tears a meningeal artery (most commonly the middle meningeal artery). An EDH is an arterial bleed that can expand rapidly, causing swift neurologic decline. Immediate identification is critical for surgical evacuation.

Subdural Hematoma (SDH): More common than EDH, an SDH results from the tearing of bridging veins. While the bleeding is venous and often slower, large acute SDHs can exert significant mass effect and are associated with severe underlying brain injury.

Intraparenchymal Hemorrhage and Contusion: These are bruises or bleeds within the brain tissue itself, typically occurring at the site of impact (coup injury) or on the opposite side (contrecoup injury). They can contribute to increased intracranial pressure and focal neurologic deficits.

Traumatic Subarachnoid Hemorrhage (tSAH): Bleeding into the subarachnoid space is a common finding in moderate-to-severe TBI and indicates a significant force of injury. While often managed non-operatively, its presence is a marker of injury severity.

Depressed or Basilar Skull Fractures: While not an injury to the brain itself, identifying significant skull fractures is crucial. Depressed fractures may require surgical elevation, and basilar skull fractures increase the risk of cerebrospinal fluid leaks, meningitis, and cranial nerve injuries.

Why Is CT Head Without IV Contrast the Recommended Study for This Presentation?

For a child with moderate or severe acute head trauma, the choice of initial imaging must prioritize speed, accessibility, and high sensitivity for the most urgent diagnoses. The ACR panel designates CT head without IV contrast as Usually appropriate because it optimally balances these needs.

The primary strength of non-contrast CT is its exceptional ability to detect acute hemorrhage. Fresh blood is hyperdense (appears bright white) on CT, making epidural, subdural, subarachnoid, and intraparenchymal hemorrhages readily apparent. It is also the best modality for identifying acute skull fractures. In a patient with a low GCS, time is critical; a modern multidetector CT scan can be completed in seconds, providing the necessary information for a neurosurgeon to make life-or-death decisions.

Alternative studies are rated Usually not appropriate for this initial evaluation for several key reasons:

  • MRI head without or with IV contrast: While MRI offers superior detail of brain parenchyma and can detect subtle injuries like diffuse axonal injury, it is not the appropriate first-line test. MRI scans take significantly longer, require the patient to be perfectly still (often necessitating sedation, which is risky in a patient with a compromised airway or unstable intracranial pressure), and are less sensitive for detecting acute skull fractures.
  • Radiography (Skull X-rays): This modality is definitively outdated for this indication. A skull radiograph can identify a fracture but provides no information about the underlying brain, which is the primary organ of concern. A patient can have a lethal intracranial hemorrhage with no skull fracture, rendering skull films dangerously insufficient.

The use of ionizing radiation is a valid concern in children. A non-contrast head CT carries a pediatric relative radiation level of ☢☢☢ (0.3-3 mSv). However, in the setting of a potentially life-threatening brain injury, the diagnostic benefit of rapidly identifying a surgically correctable lesion far outweighs the small long-term risk from radiation exposure. Intravenous contrast is not necessary for the initial scan, as the goal is to find acute blood, which is conspicuous on its own. Adding contrast would increase scan time, radiation dose, and carry a small risk of allergic reaction or nephrotoxicity without adding value to the primary clinical question.

Once you’ve decided on this study, our protocol guide covers the technique, contrast, and reading principles: CT Brain Without Contrast.

What’s Next After CT Head Without IV Contrast? Downstream Workflow

The results of the initial non-contrast head CT will dictate the immediate next steps in management. The workflow branches based on whether a critical, surgically-addressable finding is present.

If the CT is positive for a significant injury: The discovery of a large epidural or subdural hematoma with mass effect, a depressed skull fracture, or significant intraparenchymal hemorrhage triggers an immediate consultation with neurosurgery. The patient will be admitted to a high-acuity setting, such as a pediatric intensive care unit (PICU), for close neurologic monitoring, management of intracranial pressure (ICP), and potential operative intervention like a craniotomy for hematoma evacuation.

If the CT is negative: A “negative” CT scan in a child with a GCS of 13 or less does not mean the child is out of danger. This patient still has a clinically significant brain injury. A negative scan rules out a large, space-occupying lesion requiring immediate surgery, but the child requires admission for close observation and frequent neurologic checks. A declining GCS or the development of new focal deficits would prompt a repeat CT scan to look for a delayed hemorrhage or worsening edema.

If the CT is indeterminate or shows non-specific findings: In some cases, the CT may show subtle signs of injury, such as small contusions or trace subarachnoid hemorrhage, without a clear surgical target. If the child’s neurologic status fails to improve as expected or if there is concern for non-hemorrhagic injuries like diffuse axonal injury (DAI), a follow-up MRI may be considered once the patient is stable. This transitions the workup into a subacute phase, aligning more closely with the ACR scenario for “Subacute blunt head trauma with cognitive or neurologic signs.”

Pitfalls to Avoid (and When to Get Help)

In this high-stakes clinical scenario, several common pitfalls can compromise patient care. First, do not delay imaging for a child with a GCS of 13 or less; the scan should be obtained as soon as the patient is medically stabilized. Second, always remember to clinically or radiographically clear the cervical spine, as C-spine injuries frequently coexist with severe head trauma. Third, a negative initial CT is not a free pass for discharge; the clinical exam (GCS) dictates the need for admission and observation. Finally, ensure the CT scanner is using a pediatric-specific, low-dose protocol to adhere to the ALARA (As Low As Reasonably Achievable) principle for radiation safety. If the patient’s GCS worsens or new neurologic signs appear at any point, this is a critical event requiring immediate escalation to the senior physician and the neurosurgery team.

Related ACR Topics and Tools

This article covers one specific, high-acuity scenario in pediatric head trauma. For a comprehensive overview of all related clinical variants, from minor trauma to subacute presentations, and to explore the tools that support evidence-based imaging decisions, please see the following resources:

Frequently Asked Questions

Why not order an MRI first since it has no radiation?

While MRI avoids radiation, it is not the appropriate initial test for severe acute head trauma. CT is dramatically faster, more readily available, and better at detecting acute skull fractures. In a patient with a low GCS who may be unstable, the speed of CT is critical. The prolonged scan time and need for patient stillness make MRI impractical and potentially unsafe as the first-line study.

What if the child’s GCS is 14 or 15?

A GCS of 14 or 15 classifies the injury as minor head trauma. This is a different clinical scenario where the decision to image is guided by validated clinical decision rules, such as the PECARN criteria, to identify children at very low risk for whom imaging can be safely avoided.

Is a CTA (CT Angiography) ever needed initially?

For the initial screening of a child with blunt head trauma, a non-contrast CT is the standard. A CTA is usually not appropriate as the first step. It may be considered as a secondary study if there is a specific concern for vascular injury, such as a skull fracture crossing the path of a major dural venous sinus or carotid canal, or if a stroke is suspected.

What does a GCS of 13 or less mean in practical terms?

A Glasgow Coma Scale score of 13 or less signifies a moderate to severe brain injury. Practically, this means the child is not fully alert and oriented. A score of 13 might represent a child who is confused and lethargic. A score of 8 or less indicates a coma, where the child does not open their eyes, follow commands, or speak coherently. This clinical finding is the key trigger for this urgent imaging pathway.

If the non-contrast head CT is negative, can the child be discharged home?

No. A child with a GCS of 13 or less has a clinically significant brain injury, regardless of the initial imaging findings. A negative CT rules out an immediate surgical emergency but does not rule out other injuries (like diffuse axonal injury) or the potential for delayed swelling or bleeding. These patients require admission to the hospital for close neurologic monitoring.

Reviewed by Pouyan Golshani, MD, Interventional Radiologist — May 29, 2026