II. Indications
-
Cerebrovascular Accident
- Differentiate Hemorrhagic CVA from Ischemic CVA
- More sensitive than LP for Intracranial Hemorrhage
-
Test Sensitivity diminishes from time of Hemorrhagic CVA
- Test Sensitivity 95-100% at 12 hours from onset
- Test Sensitivity 50% at 7 days from onset
- Hemorrhagic CVA is not detectable on CT Head at 2-3 weeks from onset
- Suarez (2006) N Engl J Med 354(4): 387-96 [PubMed]
-
Brain Tumors (larger than 2-4 mm)
- Enhanced with iodinated Contrast Material
- Hydrocephalus
- Subdural Hematoma
- Evaluation of Traumatic Head Injury
- CT Head in every Severe Head Injury
- CT Head in every Moderate Head Injury
- See Head Injury CT Indications
- See Head Injury CT Indications in Children
III. Interpretation
- See CT Scan Window Width
- Describes CT Windows for Brain Window or Subdural Window
-
Hemorrhage appearance on CT changes with time
- Acute Hemorrhage: Hyperdense (light, white)
- Whiter than brain matter
- Subacute Hemorrhage: Isodense
- Similar density to brain matter and may be missed
- Chronic Hemorrhage: Hypodense (dark)
- Darker than brain matter
- Old Subdural Hematoma may appear as a hygroma
- Acute Hemorrhage: Hyperdense (light, white)
IV. References
- Broder (2021) Crit Dec Emerg Med 35(5): 10-1
- Haydel (2000) N Engl J Med 343:100-5 [PubMed]