See related article, p 290 . The strong evidence for benefits of rapid thrombectomy in patients with acute ischemic stroke (AIS) is challenging prehospital systems around the world. Although high-tech endovascular treatment (EVT) works only for a minority of patients, healthcare systems cannot afford to miss suitable candidates anymore. Recent figures show eligibility of ≈25% for thrombolysis and ≈10% for EVT in all AIS arriving at the hospital within 24 hours.1 Still, paramedics, local hospitals, and primary stroke centers are struggling to clinically identify the AIS patients who are likely to have intracranial large vessel occlusions (LVO) in the anterior and posterior circulation. A similar problem was posed 20 years ago when we needed to identify suspected stroke patients requiring immediate transfer to a thrombolyzing institution. Several prehospital schemes proved to be useful, such as the Cincinnati Prehospital Stroke Scale, the Los Angeles Prehospital Stroke Screen, or the Face-Arm-Speech-Time test (FAST). Still, even today, no uniform score with a single cutoff is widely accepted. Many prehospital systems use simple descriptive terms for patient selection that include a maximal delay since last proof of good health, a potentially disabling neurological deficit, absence of a major preexisting handicap, and absence of initial seizures. Whether we use a score or a simple descriptive algorithm, most stroke-admitting hospitals accept a significant rate of overdiagnosis of AIS that are considered potentially thrombolysable in the prehospital phase. Such overdiagnosed patients may have rapidly improving and minor strokes, stroke mimics, or intracranial hemorrhages. As for the new challenge of identifying patients eligible for EVT, that is, patients having an acute LVO and coming rapidly to the attention of the emergency medical system, there is a seemingly simple solution: get the patient to a computed tomography/computed tomographic angiography or magnetic resonance/magnetic resonance angiography as fast …