CT scan in the investigation of stroke

Last reviewed 01/2018

CT's are attractive on account of their simplicity to perform, rapidity, largely non-invasive nature, low cost and ability to distinguish ischaemia and haemorrhage.

Disadvantages in the assessment of ischaemic stroke:

  • the full extent of infarcted tissue cannot be defined until several days afterwards
  • CT scans are best done promptly, preferably within 48 hrs of, and no later than 7 days after, the onset of symptoms (1)
  • there may be a period of isodensity at day 3
  • repeat scans are essential to determine prognosis
  • visualisation may be assisted using contrast media but at the increased complexity and risk
  • the brainstem structures are poorly displayed because of bony artifacts

Disadvantage in the assessment of haemorrhage:

  • difficult to distinguish primary cerebral haemorrhage from confluent haemorrhagic infarction


  • 1. Drug and Therapeutics Bulletin 1998; 36 (7): 51-6.