Alberta Stroke Program Early CT Score (ASPECTS)

ASPECTS Calculator

Caudate (C)

Lentiform (L)

Insular Cortex (IC)

Internal Capsule (I)

M1 (Anterior MCA Cortex)

M2 (MCA Cortex Lateral to Insular Ribbon)

M3 (Posterior MCA Cortex)

M4 (Anterior MCA Territory Above M1-M3)

M5 (Lateral MCA Territory Above M1-M3)

M6 (Posterior MCA Territory Above M1-M3)

Score:–

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Determines MCA stroke severity using available CT data.

Why Use

Identifying patients with a greater likelihood of poor functional outcome (scores <8) may be helpful in the early stages of care for supporting transfer or therapy decisions.

When to Use

Patients presenting in the first minutes and hours of a stroke with clinical suspicion for middle cerebral artery occlusion.

Formula

To compute the ASPECTS, 1 point is subtracted from 10 for any evidence of early ischemic change for each of the defined regions. A normal CT scan receives an ASPECTS of 10 points. An ASPECTS of ≤7 points highly correlates with negative functional outcome, determined by Modified Rankin Scale (mRS) . An ASPECTS of 0 indicates diffuse involvement throughout the MCA territory. Subcortical structures are allotted 3 points (C, L, and IC). MCA cortex is allotted 7 points (insular cortex, M1, M2, M3, M4, M5, and M6). Regions: C - Caudate IC - Internal Capsule L - Lentiform nucleus I - Insular ribbon M1 - Anterior MCA cortex M2 - MCA cortex lateral to the insular ribbon M3 - Posterior MCA cortex M4* M5* M6* *Anterior, lateral and posterior MCA territories immediately superior to M1, M2 and M3, rostral to basal ganglia.

Pearls / Pitfalls

Quantifies CT changes in early middle cerebral artery stroke. More early changes seen on CT suggest poorer outcome from stroke. Patients with scores ≥8 have a better chance for an independent outcome. Points to keep in mind: The score does not consistently predict treatment response or intracranial hemorrhage or offer nuanced prognostic information. ASPECTS has mainly been studied in patients treated with or eligible for stroke reperfusion therapy (tPA), which many stroke patients do not qualify for.

Management

In patients presenting with symptoms concerning for ischemic stroke, the following are generally considered standard practice: Neurology consultation. Determine onset of stroke symptoms, or time patient last felt or was observed normal. Stat head CT to rule out hemorrhagic stroke. In appropriate circumstances and in consultation with both neurology and the patient, consider IV thrombolysis for ischemic strokes in patients with no contraindications. Always consider stroke mimics in the differential diagnosis, especially in cases with atypical features (age, risk factors, history, physical exam), including: Recrudescence of old stroke from metabolic or infectious stress. Todd’s paralysis after seizure. Complex migraine. Pseudoseizure or conversion disorder.

Critical Actions

The ASPECTS relies on subtle CT findings and thus requires an experienced radiologist. Its only validated use is as a binary variable (<8 vs ≥8) for general outcome prediction in those eligible for reperfusion therapy. For patients being considered for intra-arterial tPA administration, ASPECTS may be useful to exclude patients not likely to do well in terms of functional independence (i.e., intra-arterial treatment likely to be futile) ( Yoo 2014 ).

Advice

Using the traditional cutoff (<8 vs ≥8) as a rough estimate for predicting independence may help inform decisions. ASPECTS suggests that early CT changes in stroke may be a harbinger of poor outcomes. More recent studies have evaluated ASPECTS on the basis of the entire scale, as well as dichotomous (<8 vs ≥8) or trichotomous (0-4, 5-7, and 8-10) divisions, but few robust prospective trials have been conducted ( Prakkamakul 2017 ).

More Information

The ASPECTS is determined from evaluation of two standardized regions of the MCA territory: the basal ganglia level, where the thalamus, basal ganglia, and caudate are visible, and the supraganglionic level, which includes the corona radiata and centrum semiovale. All cuts with basal ganglionic or supraganglionic structures visible are required to determine if an area is involved. The abnormality should be visible on at least two consecutive cuts to ensure that it is truly abnormal rather than a volume averaging effect.