II. 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
  4. Subdural Hematoma
  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

III. Interpretation

  1. See CT Scan Window Width
    1. Describes CT Windows for Brain Window or Subdural Window
  2. 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

IV. References

  1. Broder (2021) Crit Dec Emerg Med 35(5): 10-1
  2. Haydel (2000) N Engl J Med 343:100-5 [PubMed]

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