CT-imaging in Acute Ischemic Stroke: Thrombus Characterization and Technique Optimization

Abstract

In this thesis two main subjects were discussed. First, histopathologic and CT characteristics of cerebral thrombi were examined. Second, techniques to increase the accuracy and to optimize CT-perfusion (CTP)- and CT-angiography (CTA)-imaging were explored. In part 1 we investigated the relation between the cause of stroke, the success of intravenous thrombolysis and the pathologic components of thrombi with the attenuation of thrombi on Non-Contrast CT (NCCT). First, we looked at the relation between thrombus attenuation and different stroke subtypes on 1-mm NCCT. We found that cardioembolic thrombi showed least dense vessel signs and lowest attenuation, followed by thrombi due to large artery atherosclerosis and dissection thrombi. Second, we performed a histopathologic analysis exploring the relation of thrombus components with the different stroke subtypes and thrombus attenuation. In a histopathologic analysis on 22 cerebral thrombi the majority of cerebral thrombi was fresh and thrombi originating from large artery atherosclerosis had a higher percentage of red blood cells (RBCs) than cardioembolisms and large artery atherosclerosis was the only stroke subtype with red (RBC-rich) thrombi. Third, we investigated whether thrombus density is related to recanalization and can predict the likelihood of a persistent occlusion after intravenous thrombolysis (IV-rtPA). We found that lower absolute HU and relative HU were independently related to persistent occlusion. Cut-off values of