ASPECTS

Created 22/03/2021, last revision 25/09/2023

the Alberta Stroke Program Early CT Score (ASPECTS) is used to standardize and increase the reliability of detecting early signs of ischemia
ASPECTS can be assessed on:
- non-contrast CT (NCCT) – adjust width/level
- 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)

a 10-point quantitative CT scan score used for evaluating patients with stroke in the MCA territory
a score of 10 points indicates 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
- M1-3 are 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 ventricles
  - 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]

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