Characterization of arterial thrombus composition by magnetic resonance imaging in a swine stroke model.

BACKGROUND AND PURPOSE The aim of this study is to analyze the histological composition of acute arterial thrombi and their MRI signals. METHODS Two different types of experimental thrombi, erythrocyte- and fibrin-rich thrombus, were created and injected into an experimentally formed stenotic common carotid artery in swine. MRI of the in vivo and in vitro samples was obtained immediately after the thrombus application. RESULTS Erythrocyte component showed high on fluid-attenuated inversion recovery, and iso on T2-weighted signal in both in vitro and in vivo. Fibrin-rich thrombus was composed of fibrin/platelet and nucleated cell layers, which demonstrated iso- and low intensities, respectively, in both fluid-attenuated inversion recovery and T2-weighted images in vitro. Mixed signal was obtained in vivo. CONCLUSIONS We successfully characterized the only erythrocyte component of acute thrombus by MRI.