• CT
• Stroke

The treatment of emergent large vessel occlusion (ELVO) was revolutionized by endovascular thrombectomy (EVT). The identification of eligible patients for EVT has sparked significant interest in determining the neuroimaging modality that offers optimal results. The American Stroke Association recommend the use of both non-contrast CT and CT angiogram for patients coming in the early window (0–6 hours).1 In the late window (6–24 hours) the randomized trials, DAWN and DEFUSE 3, showed clinical benefit utilized some form of quantitative estimation of the core infarct.2 3 Consequently the society recommends automated perfusion CT neuroimaging in addition to non-contrast CT and CT angiogram when dealing with patients presenting in the late window (6–24 hours). Having quantitative estimates would help neurointerventionalists identify patients who already have a large core and small penumbra—factors that may be associated with procedural futility and/or symptomatic hemorrhagic transformation.

Perfusion imaging is not the only way to estimate core infarct. Though not as well delineated, signs of ischemia on non-contrast cranial CT serve the same function. The Alberta Stroke Program Early CT Score (ASPECTS) combined with the assessment of clinical severity can support the existence of penumbra and the decision to go forward with EVT—similar to what is done in the early window. Nevertheless, the reliability of ASPECTS has shown limitations in both inter-rater and intra-rater agreement, leading to the possibility of inconsistent treatment decisions for patients depending on the evaluating physician.4 Thus, patients with large core infarcts may still end up receiving EVT. This occurrence would have been highly concerning in the past. However, recent evidence from three randomized controlled trials has substantiated the efficacy of EVT in …