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CT Head

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CT Head, Head CAT Scan, Head CT, CT Brain

  • See Also
  1. Head Injury CT Indications in Adults
  2. Head Injury CT Indications in Children
  3. Head Injury CT Indications in Concussion
  • Indications
  1. Cerebrovascular Accident
    1. Differentiate Hemorrhagic CVA from Ischemic CVA
    2. More sensitive than LP for Intracranial Hemorrhage
    3. Test Sensitivity diminishes from time of Hemorrhagic CVA
      1. Test Sensitivity 95-100% at 12 hours from onset
      2. Test Sensitivity 50% at 7 days from onset
      3. Hemorrhagic CVA is not detectable on CT Head at 2-3 weeks from onset
      4. Suarez (2006) N Engl J Med 354(4): 387-96 [PubMed]
  2. Brain Tumors (larger than 2-4 mm)
    1. Enhanced with iodinated Contrast Material
  3. Hydrocephalus
    1. Temporal horn of the Lateral Ventricle dilates (axial width >=5 mm) early in Hydrocephalus
      1. Appear rounded as Hydrocephalus develops (contrast with their normal curved-slit appearance)
    2. Third Ventricle appears O-Shaped when dilated from downstream CSF obstruction
      1. Third Ventricle is normally has a more slit-like appearance
  4. Intracranial Bleeding
    1. Epidural Hematoma
    2. Subdural Hematoma
    3. Intraparenchymal Hemorrhage
    4. Subarachnoid Hemorrhage (Thunderclap Headache)
  5. Evaluation of Traumatic Head Injury
    1. CT Head in every Severe Head Injury
    2. CT Head in every Moderate Head Injury
    3. See Head Injury CT Indications
    4. See Head Injury CT Indications in Children
  • Interpretation
  1. See CT Scan Window Width
    1. Describes CT Windows for Brain Window or Subdural Window
  2. Systematic Head CT Approach Mnemonic: "Blood Can Be Very Bad"
    1. B: Blood
    2. C: Cisterns
    3. B: Brain
    4. V: Ventricles
    5. B: Bone
  3. Hemorrhage appearance on CT changes with time
    1. Acute Hemorrhage: Hyperdense (light, white)
      1. Whiter than brain matter
    2. Subacute Hemorrhage: Isodense
      1. Similar density to brain matter and may be missed
    3. Chronic Hemorrhage: Hypodense (dark)
      1. Darker than brain matter
      2. Old Subdural Hematoma may appear as a hygroma
  • References
  1. Broder (2024) Crit Dec Emerg Med 38(7): 22-3
  2. Broder (2021) Crit Dec Emerg Med 35(5): 10-1
  3. Haydel (2000) N Engl J Med 343:100-5 [PubMed]