Stroke (summary)

Radiopaedia • CC-by-nc-sa 3.0 • de
This is a basic article for medical students and other non-radiologists

Stroke is a clinical diagnosis where an acute neurological deficit follows a cerebrovascular insult. There are two main groups of stroke: ischemic (>80%) or hemorrhagic (<20%) .

Reference article

This is a summary article; read more in our article on stroke.

Summary

  • anatomy
  • epidemiology
    • common
    • leading cause of disability
    • third highest cause of mortality in the UK
  • presentation
    • sudden neurological deficit
    • manifest symptoms depend on the vascular territories involved
    • time of onset is important when considering treatment
  • pathophysiology
    • brain parenchyma is deprived of blood flow and therefore oxygen
    • ischemic
      • arteries occluded by thrombus or embolus
      • temporary loss of blood flow may occur (TIA)
    • cell death results in edema and swelling
  • investigation
    • non-contrast CT head in the first instance
      • exclude hemorrhage or other cause
      • may show hyperdense vessel or evidence of infarction
    • CT angiography
      • some centers use this to identify blockages and assess collaterals when planning clot retrieval
    • MRI
      • less commonly used for acute events, but good for identifying infarcts (especially using DWI sequences)
    • ultrasound
      • carotid Doppler ultrasound in the peri-stroke period to select patients who may benefit from endarterectomy
  • treatment
    • thrombolysis or thrombectomy
      • ischemic strokes <4.5 hours old
      • depends on the local protocol
      • should be discussed with an acute stroke service
    • stroke patients should be managed in a stroke center
    • oral antiplatelet therapy
    • medical management of hypertension and risk factor reduction

Imaging

  • role of imaging
    • is there evidence of stroke?
    • what is the distribution and severity of the stroke?
    • is there hemorrhagic transformation?
    • is a cause visible, e.g. in situ thrombus?
    • are there contraindications to IV thrombolysis?
    • are there indications for clot-retrieval?
    • is there significant carotid stenosis?
  • radiographic features
    • CT
      • parenchymal infarction may not be visible in the acute setting
      • with time, cytotoxic edema causes reduced density on CT
      • clot within a vessel may be seen as hyperdensity
      • acute hemorrhage will appear dense
    • MRI
      • the most important sequence is the DWI (diffusion sequence)
      • diffusion restriction in this context is highly sensitive for ischemia
    • angiography (CTA/MRA/DSA)
      • assessment of arterial supply to confirm whether a clot is present
    • perfusion (CT/MRI)
      • assessment of ischemic/infarcted areas
      • ischemia may be reversible
    • carotid Doppler
      • not in the acute setting but usually within two weeks following onset
      • assessment of the neck vessels looking for carotid stenosis
      • if >70% stenosis on affected side, surgery may be offered