CT imaging in acute ischemic stroke

Time is of the essence when treating acute ischemic stroke, to limit the damage caused. One form of intra-arterial treatment (IAT) used in such cases is the mechanical removal of the blood clot using stent-retrievers. It is thought that patient selection for IAT requires improvement and that CT imaging might be useful to improve this selection. The aim of this thesis is to increase insight into the value of CT-based patient selection for IAT. There are at least three important requirements CT imaging biomarkers must fulfill to become a valuable tool for patient selection. First, there should be treatment modification by the imaging biomarker. Treatment effect modification means that the treatment effect differs for subgroups of patients. If IAT is effective for one subgroup of patients but not for another subgroup of patients, there is a rationale to select patients. Therefore, a first step towards the use of CT imaging for patient selection should be to determine if there is treatment effect modification. Second, measurement of the imaging biomarker must be robust because erroneous determination of a biomarker may result in incorrectly withholding a patient from treatment. Third, if image data is used for patient selection all image data must be available to the interventionalist before a patient is transferred for IAT so that the interventionalist can determine whether the patients is eligible for IAT. This thesis consists of 2 parts. In the first part a cloud-based platform for telemedicine in acute ischemic stroke care is presented. Furthermore, the accuracy of several CT-based biomarker measurements is determined. In the second part the association of several CT biomarkers with outcome in patients with acute ischemic stroke is evaluated. Moreover, it was investigated whether these CT biomarkers modify the treatment effect of IAT compared to best medical care, including IV alteplase.