Imaging of Patients with Suspected Large-Vessel Occlusion at Primary Stroke Centers: Available Modalities and a Suggested Approach

Abstract

The overwhelming benefit of endovascular therapy in patients with large-vessel occlusions suggests that more patients will be screened than treated. Some of those patients will be evaluated first at primary stroke centers; this type of evaluation calls for standardizing the imaging approach to minimize delays in assessing, transferring, and treating these patients. Here, we propose that CT angiography (performed at the same time as head CT) should be the minimum imaging approach for all patients with stroke with suspected large-vessel occlusion presenting to primary stroke centers. We discuss some of the implications of this approach and how to facilitate them.

FIGURE.

The workflow of patients with LVO stroke arriving first at a primary stroke center. Once patients arrive at the PSC, steps that can introduce delay in the door-in-door-out time interval include clinical and imaging assessments and the time spent on each of the various imaging modalities (the length of the arrows corresponds to the relative duration needed to complete, process, and interpret each technique). Following imaging, the decisions to administer intravenous thrombolytics (IVT) and whether to transfer to comprehensive stroke centers for endovascular thrombectomy can introduce some delay. Transfer to CSCs is preferably done by the same Emergency Medical Service (EMS) team that brought the patient to the PSC. Once the patient arrives at a CSC, repeat imaging can be considered in selected patients (*), given the low likelihood of recanalization of LVO with intravenous thrombolytics and the variability of CT ASPECTS decay. Repeat imaging at the CSC will further delay the time interval from imaging at the PSC to arterial puncture. mCTA indicates multiphase CTA; sCTA, single-phase CTA; angio, angiography.