The Alberta Stroke Program Early CT Score (ASPECTS) is a valuable tool used in the assessment of acute ischemic stroke (AIS) patients based on noncontrast axial CT scans. It aids in identifying regions of the brain affected by ischemia and helps predict patient outcomes. Here's how it works and what different scores mean:

Understanding ASPECTS:

Principle: ASPECTS divides the middle cerebral artery (MCA) territory into 10 regions, each representing a different part of the brain.

Scoring System: Starting with a perfect score of 10, points are subtracted based on signs of early ischemic changes seen in each region. These changes include swelling or hypoattenuation (a decrease in attenuation relative to other brain areas).

Regions Assessed: ASPECTS evaluates 10 regions: 3 subcortical structures (caudate, lentiform nucleus, internal capsule), and 7 cortical territories (insular cortex and M1 through M6).

Interpretation: A lower ASPECTS score indicates a more significant ischemic insult and is associated with worse outcomes.

Interpretation of Scores:

Score of 10: No ischemic changes detected, indicating a normal brain.

Score of 8-10: Mild ischemic changes, suggesting a relatively small infarction and a favorable prognosis.

Score of 5-7: Moderate ischemic changes, indicating a larger infarction with a less favorable prognosis.

Score of ≤4: Severe ischemic changes, signifying a substantial infarction with a poor prognosis.

Clinical Implications:

Prognostic Tool: ASPECTS helps clinicians predict patient outcomes following an acute ischemic stroke.

Treatment Guidance: Lower ASPECTS scores may influence treatment decisions, such as eligibility for thrombolytic therapy or endovascular interventions.

Monitoring Progression: Serial ASPECTS assessments can track the progression of ischemic changes over time and guide ongoing management.

Limitations:

MCA Distribution: ASPECTS primarily assesses MCA territory infarcts and may not capture strokes affecting other vascular distributions.

Unequal Weighting: Cortical territories are not equally weighted in the ASPECTS system, potentially leading to underestimation of certain infarcts' severity.