CT Head

Aka: CT Head, Head CAT Scan, Head CT, CT Brain

advertisement

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
    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

III. 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

IV. 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]

Images: Related links to external sites (from Bing)

These images are a random sampling from a Bing search on the term "CT Head." Click on the image (or right click) to open the source website in a new browser window. Search Bing for all related images

Related Studies

Related Topics in Radiology

advertisement