Patients with similar infarct volumes after acute ischemic stroke often experience markedly different functional outcomes, suggesting that additional imaging features may influence prognosis. A post hoc analysis published in Journal of the American Heart Association evaluated whether 24-hour computed tomography (CT) infarct density provides complementary prognostic information beyond infarct volume.
The analysis used data from the AcT (Alteplase Versus Tenecteplase in Acute Ischemic Stroke Within 4.5 Hours) trial and included patients with detectable 24-hour CT infarcts without parenchymal hematoma. Infarct density was quantified using a standardized metric derived from Hounsfield unit measurements. The primary outcome was the 90-day ordinal modified Rankin Scale (mRS) score.
Findings
- A total of 839 patients with acute ischemic stroke and detectable 24-hour CT infarcts were included in the analysis.
- Standardized infarct density significantly modified the association between infarct volume and 90-day functional outcome (P-interaction = 0.001).
- Infarct density also significantly modified the relationship between infarct volume and mortality (P-interaction = 0.014).
- Higher standardized infarct density, reflecting less severe infarct injury, was independently associated with better 90-day functional outcomes (adjusted common odds ratio [acOR] 0.87; 95% confidence interval [CI] 0.80-0.96 per 1 standardized-Hounsfield unit increase).
- After adjustment, infarct volume was not independently associated with 90-day functional outcome (acOR 0.96; 95% CI 0.90-1.01 per 5-mL increase).
Twenty-four-hour CT infarct density and infarct volume provided complementary information regarding infarct burden and prognosis after acute ischemic stroke. Higher infarct density was independently associated with better functional outcomes and modified the relationship between infarct volume, disability, and mortality.
