Advanced CT imaging in acute ischemic stroke

Abstract

Acute ischemic stroke is one of the most prevalent causes of death and disability in the world. Patients with suspected stroke or transient ischemic attack usually undergo computed tomography (CT) imaging in the acute phase, including non-contrast CT, CT perfusion (CTP) and CT angiography (CTA). The aim of this thesis was to improve diagnostic (part 1) and prognostic (part 2) aspects of stroke care with advanced (dual-energy) CT imaging techniques. First, we demonstrated that a technique called CTA derived virtual non-contrast CT is non-inferior to conventional non-contrast CT for the detection of early signs of brain infarction. Second, we identified pitfalls of automated post-processing CTP images, which can lead to wrong treatment decisions. Third, we showed that the concordance between collateral circulation assessments on CT and invasive digital subtraction angiography (DSA) was poor, and that collateral circulation evaluated on CTP-derived CTA, but not on standard single-phase CTA or DSA, was predictive of functional outcome after ischemic stroke. Fourth, we found that extending the (dual-energy) CTA to cover the heart (head-to heart) increases the chance of detecting cardiac thrombi and helps to identify cardioembolic sources in the acute stage of ischemic stroke. Fifth, we found that the pattern of intracranial vessel wall calcifications has prognostic value for the outcome after intravenous thrombolysis. Sixth, we showed that the ratio between cerebrospinal fluid volume and intracranial volume is an important predictor of malignant edema. Last, predictors of recurrent ischemic stroke were systematically reviewed in the literature and we identified additional imaging predictors of recurrent ischemic stroke in a cohort study. In conclusion, this thesis showed that advanced (dual-energy) CT imaging techniques have diagnostic and prognostic value in patients with acute ischemic stroke.