We explored whether clot density in middle cerebral artery (MCA) occlusion is related to clinical variables, stroke etiology, blood constituents, and prestroke medication. We performed a retrospective chart review of patients with acute ischemic stroke of the anterior circulation admitted to two Central European stroke centers. The acquisition of non-contrast enhanced CT (NECT) and CT angiography (CTA) within 4.5 h of symptom onset was obligatory. We assessed the site of MCA occlusion as well as density, area, and length of the clot in 150 patients. The Hounsfield unit values for the clot were divided with contralateral MCA segment to yield relative Hounsfield Unit ratio (rHU). The site of the vessel occlusion (M1 vs. M2) and antiplatelet usage, but not stroke etiology, significantly influenced rHU. We found an inverse correlation of rHU with erythrocyte count (p < 0.001). The multivariate analysis revealed that a higher rHU (i.e., clot being more hyperdense) was more likely with the use of antiplatelets (OR 4.24, CI 1.10-16.31, p = 0.036). Erythrocyte (OR 0.18, CI 0.05-0.55, p = 0.003), and thrombocyte counts (OR 0.99, CI 0.98-0.99, p = 0.029) were associated with odds for more hypodense clots (lower rHU). Our study disclosed that antiplatelet therapy impacts the composition of intracranial clots of the anterior circulation.
Keywords: antiplatelets; clot; computed tomography; hyperdense artery sign; ischemic stroke.