ASPECTS (Alberta Stroke Program Early CT Score) Calculator

ASPECTS (Alberta Stroke Program Early CT Score): Explanation and Clinical Context The Alberta Stroke Program Early CT Score (ASPECTS) is a 10-point quantitative CT-based scoring system designed to detect and quantify early ischemic changes within the middle cerebral artery (MCA) territory on non-contrast head CT. The MCA territory is divided into ten defined regions (four subcortical: caudate head [C], lentiform nucleus [L], internal capsule [IC], insular ribbon [I]; and six cortical: M1–M6). The initial score is 10; one point is subtracted for each region that demonstrates early ischemic change (hypodensity, loss of gray–white differentiation, or sulcal effacement) so that the final ASPECTS ranges from 0 (extensive ischemia of the MCA territory) to 10 (no visible early ischemic change).

Clinically, higher ASPECTS indicates smaller infarct core and better prognosis; many modern guidelines and thrombectomy trial selection criteria use ASPECTS thresholds (commonly ASPECTS >6) to help select patients for reperfusion therapies such as mechanical thrombectomy when correlated with clinical findings and vascular imaging. ASPECTS is quick, reproducible with training, correlates with diffusion-weighted MRI infarct volume, and has demonstrated prognostic value for functional outcome and hemorrhagic transformation risk.