A stroke occurs when blood flow to a part of the brain is interrupted, either by a blocked artery (ischemic stroke) or a ruptured blood vessel (hemorrhagic stroke). This interruption deprives brain cells of oxygen and nutrients, leading to cell damage and potential loss of function. Rapid assessment is paramount in stroke care to determine the type and extent of brain damage, guiding timely treatment. Medical professionals utilize various tools for quick evaluation, and one such tool is the Alberta Stroke Program Early CT Score (ASPECTS).
What is ASPECTS
ASPECTS stands for the Alberta Stroke Program Early CT Score. It is a standardized, quantitative scoring system used to quickly assess early ischemic changes in the brain on a non-contrast computed tomography (CT) scan in patients experiencing an acute ischemic stroke. Its purpose is to aid in time-sensitive decision-making by providing an objective measure of the extent of early brain damage.
ASPECTS was developed to offer a reliable and reproducible method for assessing early ischemic changes within the middle cerebral artery (MCA) territory, which is a common area affected by ischemic strokes. This standardized approach helps identify patients with acute large vessel occlusion and can be used as part of the assessment for eligibility in receiving mechanical thrombectomy treatment. The score is easily applicable in many settings worldwide, as it can be used on any modern CT scanner without additional processing steps.
How ASPECTS is Measured
The ASPECTS score ranges from 0 to 10 points, with 10 representing a normal brain scan with no signs of early ischemic damage. Points are subtracted from this initial score of 10 for specific regions of the brain that show signs of early ischemic changes. The assessment involves evaluating two standard axial CT slices: one at the level of the basal ganglia and another immediately above at the level of the lateral ventricles.
Ten key brain regions within the middle cerebral artery territory are assessed. These include the caudate, lentiform nucleus (putamen), internal capsule, and insular cortex. Additionally, six cortical regions are evaluated, often referred to as M1, M2, M3, M4, M5, and M6. Each affected region reduces the score by one point, meaning that if all 10 regions show signs of damage, the score would be 0.
Understanding Your ASPECTS Score
A higher ASPECTS score indicates less early ischemic damage, suggesting a smaller area of the brain has been affected by the stroke. Conversely, a lower score, closer to 0, signifies more extensive and widespread early brain damage.
A score of 7 or higher indicates that patients may benefit from certain treatments and correlates with a better prognosis. However, a score of 7 or less suggests significant early ischemic changes in the brain. Patients with lower scores may experience a worse functional outcome. The score provides a quantitative measure that helps predict both functional outcomes and the risk of symptomatic hemorrhage.
ASPECTS and Stroke Treatment
The ASPECTS score plays a direct role in guiding treatment decisions for acute ischemic stroke. It helps determine a patient’s eligibility for reperfusion therapies, which aim to restore blood flow to the brain. These therapies include intravenous thrombolysis, using medications like alteplase or tenecteplase, and mechanical thrombectomy, a procedure to physically remove a blood clot.
A higher ASPECTS score, indicating less extensive damage, makes a patient a more suitable candidate for these interventions. For example, studies have shown that patients with a high ASPECTS score are more likely to benefit from thrombolysis. Conversely, a lower ASPECTS score suggests more widespread damage, which may contraindicate certain treatments or increase the risk of complications like symptomatic hemorrhage after thrombolysis. The score helps physicians quickly identify early ischemic changes, aiding stroke teams in making faster triage or transfer decisions and ensuring patients receive appropriate treatment options.