Evaluation of Early Computed Tomographic Findings in Acute Ischemic Stroke

BACKGROUND AND PURPOSE: Detection of large, hypoattenuated brain-tissue volume on hyperacute CT scan has been suggested as an exclusion criterion for early intravenous tissue plasminogen activator (IV-tPA) treatment. This study assessed the reliability of detection for these findings and their relationship to outcome. METHODS: Fifty hyperacute CT scans (33%) and the presence of a hyperdense MCA. Evaluations were compared with 24-hour scan results, 30-day infarct volumes, and baseline NIH stroke scale scores (NIHSS). RESULTS: Readers reliably evaluated the degree of MCA territory hypodensity (intraclass correlation=0.53, P33% involvement with a sensitivity of 60% to 85% and a specificity of 86% to 97%. The baseline NIHSS was higher when >33% MCA hypodensity was seen (P=0. 021). Detection of significant hypodensity (>33%) correlated with poorer outcome. When >33% hypodensity was not detected, mean 30-day infarct volumes were 27.0 to 33.0 cm3, versus 84.3 to 123.1 cm3 when >33% hypodensity was present (P=0.002). CONCLUSIONS: Detection of MCA territory hypodensity on hyperacute CT scans is a sensitive, prognostic, and reliable indicator of the amount of MCA territory undergoing infarction.