Swirl sign (intracranial hemorrhage)


  • A 30 years old man
  • Involved in motor vehicle accident
  • Presented with headache and persistent vomiting
  • GCS on arrival in Emergency Department is 14/15
    Non-contrast CT brain axial plane in soft tissue window

CT scan findings:

  • There is subdural hemorrhage at right fronto-temporo-parietal region
  • Areas of hypodensity seen (red arrows) within the hemorrhage representing swirl sign
  • There is midline shift to the left side
  • Compression of ipsilateral lateral ventricle

Radiological diagnosis: Swirl sign in acute subdural hemorrhage


  • Swirl sign is seen in non-contrast CT brain in acute extradural or subdural hemorrhage.
  • ┬áIt represents unclotted blood which is hypodense compared to surrounding clotted blood which is hyperdense (50-70HU).
  • It has been verified as active bleeding site at the time of surgery
  • Identification of patients with a potential risk for hematoma expansion in acute intracranial hemorrhage is crucial for planning of the treatment and prediction of the functional outcome.
  • Swirl sign is an indicator of possible hematoma expansion and associated with higher mortality compared to patient without this sign.
Author: radhianahassan