Trauma Head

Playlist contributed by Tom Mitchell
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Aimed at ED middle grades with an interest in CT brain interpretation.

Case series of CT findings following head trauma. These should give you a flavour of both the common and more unusual traumatic findings.

  • Try to establish your diagnosis before looking at the report.
  • They are in no particular order and of varying quality, just like real life....
  • None of these images are normal. Establishing that the CT is normal and sending your patient home based on this decision is often the most tricky part of the process.
  • Non-traumatic pathology is often an incidental finding on head CT for trauma. You need to appreciate normal variants and incidental pathologies and also manage these appropriately (e.g. incidental infarct will need secondary stroke prevention consideration).
  • A normal head CT does not rule out traumatic pathology. Treat the patient. Think of spinal and arterial pathology if you have acute neurology and a normal scan.

Follow these links for more images and information



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Mnemonic for approaching trauma head CT interpretation

Blood Can BVery Bad

  • Using a systematic approach will help to ensure that significant neuropathology will not be missed
  • The CT slice is regarded as being viewed from the patient’s feet, so the left side of the picture as you view it is the right side of the patient.
  • Determine if scans have been taken with or without IV contrast, as contrast may mimic the presence of blood. IV contrast does not cross the normal blood brain barrier and is used if there is a suspicion of tumour, infection (e.g. abscess) or vascular abnormality (e.g. AVM or aneurysm)

B - Blood

  • Acute blood is bright white (once it clots)
  • Blood becomes isodense at 1wk (exact time depends on size of clot)
  • Blood becomes hypodense at 2wks (exact time depends on size of clot)
    • Extracerebral (axial) haemorrhage occurring within the skull, but outside the brain
      • Extradural haemorrhage (EDH)—biconvex lesion that does not cross suture lines; usually secondary to arterial injury. Low mortality only if treated early.
      • Subdural haemorrhage (SDH)—crescent-shaped blood collection that can cross suture lines; usually secondary to venous disruption of surface and/or bridging vessels.
      • Subarachnoid haemorrhage (SAH)—haemorrhage into the CSF and cisterns secondary to aneurysms, trauma and arteriovenous malformation.
    • Intracerebral (axial) haemorrhage occurring within the brain itself

C- Cisterns

  • Cisterns are collections of CSF, which surround and protect the brain. Examine each for evidence of effacement, asymmetry and the presence of blood.
    • Circum-mesencephalic—surrounding the midbrain
    • Suprasellar—around the circle of Willis
    • Quadrigeminal—located at the top of the midbrain
    • Sylvian—between temporal and frontal lobes.

B - Brain matter

  • Compare the sulcal pattern (gyri) for evidence of effacement and relative volumes of the left and the right sides of the brain for asymmetry. Trace the falx through the series of scans, looking for mid-line shift secondary to compartmental mass effect.
  • Look for inconsistencies in the grey–white differentiation (e.g. evolving embolic stroke). Patients with CVA may have a normal CT head scan on presentation with subtle oedema beginning at 6-12 hours, hypoattenuation after 24 hours and maximal oedema at 3-5 days.
  • Identify hyperdense regions associated with blood, IV contrast or calcification.
  • Identify hypodense regions associated with air, fat, ischaemia or tumour.

V- Ventricles

  • Examine the lateral ventricles, 3rd and 4th ventricles for asymmetry, dilatation (hydrocephalus), effacement and haemorrhage.

B - Bone

  • look for skull fractures (especially basilar) in bone windows
  • Soft tissue swelling, mastoid air cells disruption and paranasal sinuses fluid should raise the possibility of a skull fracture;
  • intracranial air means that the skull and the dura have been violated somewhere.
  • Always check for upper c-spine fractures.

Basic CT interpretation

Further anatomy resources


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