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Interpret
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Reading File
CT Brain Interpretation
Modality: Non-contrast axial CT scan of the brain
Primary Finding: Tension Pneumocephalus - "Mount Fuji Sign"
This is the dominant and immediately recognizable abnormality on this scan. There is a massive bilateral frontal subdural air collection (appearing jet-black on CT, the lowest density possible). The large air pockets compress and separate the frontal lobes, which remain tethered along the midline by the bridging veins to the superior sagittal sinus. This creates the characteristic silhouette of two mountain peaks - the classic "Mount Fuji Sign".
This sign is pathognomonic for tension pneumocephalus, meaning air is entering the intracranial compartment under a one-way valve mechanism and building up pressure, analogous to a tension pneumothorax.
Systematic Findings
| Feature | Finding |
|---|---|
| Extra-axial collection | Bilateral frontal subdural air (hypodense/black) |
| Pattern | Mount Fuji Sign - bifrontal peaked air with frontal lobe separation |
| Mass effect | Severe - posterior displacement and compression of frontal lobes |
| Midline | Anterior interhemispheric fissure compressed; overall roughly symmetric |
| Ventricles | Likely effaced/compressed at this level due to raised ICP |
| Sulci/cisterns | Diffusely effaced - sign of generalized raised intracranial pressure |
| Hemorrhage | No gross hyperdense (white) hemorrhage seen |
| Parenchyma | Crowded posteriorly; no discrete focal lesion visible |
| Bone windows | Skull base/sinus region would need dedicated review for source |
Likely Etiology
Tension pneumocephalus of this magnitude most commonly follows:
- Post-neurosurgical - posterior fossa surgery (sitting position), burr hole drainage of chronic subdural hematoma (most common surgical cause)
- Trauma - skull base or paranasal sinus fractures creating a dural defect
- Barotrauma - diving, mechanical ventilation
Clinical Significance - Neurosurgical Emergency
This is an emergency. Clinical features include rapid neurological deterioration, altered consciousness, and signs of raised ICP. Urgent management includes:
- Immediate neurosurgical consultation
- Needle aspiration or burr hole to decompress intracranial air
- High-flow 100% oxygen (accelerates nitrogen reabsorption from the air pocket)
- Identify and surgically close the dural defect/source of air entry
Summary: This CT demonstrates a classic Mount Fuji Sign consistent with bilateral frontal tension pneumocephalus - a life-threatening neurosurgical emergency requiring immediate decompression.
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