Alberta Stroke Program Early CT Score
David Goldemund M.D.
Updated on 25/12/2023, published on 22/03/2021
  • the Alberta Stroke Program Early CT Score (ASPECTS) is used to standardize and increase the reliability of detecting early signs of ischemia

    • early ischemic changes are defined as incipient parenchymal hypodensity or loss of grey and white matter differentiation
  • ASPECTS can be assessed on:
    • noncontrast CT (NCCT) – adjust width/level  Early CT signs of ischemia before and after adjustment of window parameters (level/window)
    • CT perfusion (CTP)  [Aviv, 2007]
    • CTA source images (CTA-SI)   [Puetz, 2009]
  • ASPECTS primarily evaluates the MCA territory
  • PC-ASPECTS was designed to evaluate changes in the posterior circulation
  • commercial software programs for automated ASPECTS evaluation are available  (e.g., BRAINOMIX)   Brainomix - ASPECTS 6  BRAINOMIX - automated evaluation of early ischemic changes o NCCT
MCA territory
  • a 10-point quantitative CT scan score used for evaluating patients with stroke in the MCA territory
  • a score of 10 points indicates a normal finding; 1 point is subtracted from the initial score of 10 for each region exhibiting early signs of ischemia
    • C – caudate nucleus
    • L – lentiform nucleus
    • IC – internal capsule (any portion)
    • I – insular cortex
    • C, L, IC, I, and M1-3 are assessed on axial scans at the basal ganglia level
      • M1 – anterior MCA cortex, corresponding to the frontal operculum
      • M2 – MCA cortex lateral to the insular ribbon, corresponding to the anterior temporal lobe
      • M3 – posterior MCA cortex corresponding to the posterior temporal lobe
    • M4-5 are above the basal ganglia at the level of the lateral ventricles (supraganglionic level)
      • M4 – anterior MCA territory immediately superior to M1
      • M5 – lateral MCA territory immediately superior to M2
      • M6 – posterior MCA territory immediately superior to M3
  • ASPECTS is a valuable technique for prognostic evaluation in acute ischemic stroke (thresholds may vary slightly between NCCT and CTP)
    • patients with high ASPECTS values are more likely to have favorable outcomes
    • an NCCT ASPECTS score of ≤ 7 predicts worse functional outcome at three months  [Esmael, 2021]
    • patients with CTP ASPECTS score of < 8 treated with thrombolysis mainly did not achieve favorable clinical outcomes  [Aviv, 2007]
    • the threshold for thrombectomy is gradually decreasing (probably ASPECTS 3 based on SELECT2, ANGEL ASPECT trials results) ⇒ ASPECT score will lose some of its importance because most of the patients will be treated anyway
ASPECT score
ASPECT score regions on Brainomix
Ischemic changes in I, L and M5 regions
Ischemic changes in I, M2 and M5 regions
ASPECTS 8 - hypodensities in C and L regions
Posterior circulation

PC-ASPECTS (The posterior circulation Acute Stroke Prognosis Early CT score)

  • helps to assess early ischemic changes on noncontrast (NCCT) and optionally on CTA source images (CTA-SI)
  • normal brain scores 10; points are subtracted for each affected region:
    • thalami (1 point each)
    • occipital lobes (1 point each)
    • midbrain (2 points – uni- and bilateral)
    • pons (2 points – uni- and bilateral)
    • cerebellar hemispheres (1 point each)
  • pc-ASPECTS < 8 is associated with poor prognosis   [Puetz, 2009]
  • assessing can be inaccurate in the following situations:
    • recent ischemia superimposed on an older lesion
    • extensive leukoencephalopathy
    • poor image quality
pc-ASPECT score predicts prognosis [Puetz, 2009]

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ASPECT score