ASPECTS: Alberta Stroke Programme Early CT Score for Predicting Outcome of Hyperacute Stroke

The Alberta Stroke Programme Early CT Score was created in 2000 to quantify the degree of infarcted tissue in the left or right anterior circulation within 3 hours of symptom onset. In the initial study, baseline ASPECTS value correlated (inversely) with stroke severity on the NIHSS, and predicted functional outcome and symptomatic intracerebral hemorrhage, thusly identifying patients unlikely to make an independent recovery despite IV thrombolytic treatment. Ten structures are evaluated, each valued at one point, and a point is lost if at least one-third of the area in question has focal edema or parenchymal hypoattenuation. The maximum score is ten points.

Two axial cuts of a plain CT head are evaluated. The first cut is at the level of the thalamus and basal ganglia, and the second cut is the one just rostral to the first. On the first cut, the seven areas are the caudate nucleus, lentiform nucleus, internal capsule, insular ribbon, anterior MCA cortex (M1), cortex lateral to insular ribbon (M2), and posterior MCA cortex (M3). On the second cut, the three areas are M4 (anterior), M5 (lateral), and M6 (posterior) MCA territories immediately superior to M1, M2, and M3. For a patient with an ASPECTS value of 7 or less, the risk of symptomatic intracerebral hemorrhage (ICH) with IV thrombolysis is 14%, 14 times that of patients with a score higher than 7.

More recently, the ASPECTS score has been used in large multi-center randomized control trials (such as ESCAPE) in quantifying which patients had large established infarct cores. A patient with an ASPECTS of at least 6 is considered, among other factors, a good candidate for mechanical thrombectomy.