Hemorrhagic transformation of ischemic stroke – prediction and evaluation with different computed tomography modalities

Abstract

Background: Hemorrhagic transformation (HT) of ischemic stroke is a complex and heterogeneous phenomenon, which involves numerous parameters whose knowledge remains partial. Large HT is often associated with poorer outcome and higher mortality, especially parenchymal hematoma type 2, that’s why the search of strong HT predictors is very important and can improve management of ischemic stroke patients. Our aim was to review the literature regarding computed tomography (CT) imaging predictors of HT and possible input of different computed tomography modalities in diagnosis and evaluation of HT following acute ischemic stroke. The contribution of non-contrast computed tomography, computed tomography angiography (CTA) and dynamic Perfusion CT (PCT) investigation in the prediction of the hemorrhagic transformation risk were studied. Multiple multicentre studies revealed useful information on different CT patterns predictors of symptomatic intracerebral hemorrhage after stroke, which is the most important type of hemorrhagic transformation from a clinician’s point of view. Conclusions: Data from the multiple studies and trials revealed that different CT modalities show high potency in HT prediction and evaluation. Non-contrast CT standard investigation showed high accuracy in HT prediction by assessment of early ischemic signs, quantification of the Alberta Stroke Program Early CT Score (ASPECTS), grading of leukoaraiosis severity. CTA is useful in HT prediction by the assessment of collateral vessels; intra-arterial occlusion and ASPECTS score calculated from the CTA source images. PCT showed the best predictive values by the measurement of blood-brain barrier permeability.