ASPECTS
Alberta Stroke Program Early CT Score quantifying early ischaemic change in the MCA territory.
ASPECTS is a 10-point topographic score of early ischaemic change in the middle cerebral artery territory on non-contrast CT. Ten regions each contribute one point; a point is subtracted for each region showing early ischaemic change, so 10 is normal and 0 is diffuse involvement.
📐 Formula
ASPECTS = 10 − number of affected regions
🎯 When to Use
- Assessing early ischaemic change in acute anterior-circulation stroke.
- Selecting patients for reperfusion therapy (thrombolysis / thrombectomy).
- Estimating infarct core burden and haemorrhage risk before treatment.
⚙️ How It Works
- Ten MCA regions are assessed: caudate, lentiform, internal capsule, insular ribbon, and M1–M6 cortical regions.
- Subtract one point for each region with early ischaemic hypoattenuation.
- The remaining points (0–10) are the ASPECTS.
📊 Interpreting the Result
- ≥ 8 — small core, favourable for reperfusion with better functional outcome.
- ≤ 7 — larger established core, worse outcome and higher symptomatic haemorrhage risk.
- 0 — extensive MCA-territory involvement.
⚠️ Limitations & Pitfalls
- Designed for the MCA territory only; not for posterior circulation (use pc-ASPECTS).
- Early ischaemic change is subtle and reader-dependent, especially at 0–3 hours.
- Timing of imaging affects the score.
📚 References
- Barber PA, Demchuk AM, Zhang J, Buchan AM. Validity and reliability of a quantitative computed tomography score in predicting outcome of hyperacute stroke before thrombolytic therapy (ASPECTS). Lancet. 2000;355(9216):1670-1674.
- Pexman JHW, Barber PA, Hill MD, et al. Use of the Alberta Stroke Program Early CT Score (ASPECTS) for assessing CT scans in patients with acute stroke. AJNR Am J Neuroradiol. 2001;22(8):1534-1542.
⚕️ For clinical decision support only. Always verify calculations and apply clinical judgment.