BACKGROUND To test whether portable duplex ultrasound devices can be used in a prehospital '911' emergency situation to assess intracranial arteries. METHODS Non-contrast-enhanced transcranial duplex ultrasound studies were performed either immediately at the site of the emergency (i.e. private home) or after transfer into the emergency helicopter/ambulance vehicle. RESULTS A total of 25 patients were enrolled. In 5/25 cases, intracranial vessels could not be visualized due to insufficient quality of the temporal bone window. In 20/25 cases, bilateral visualization and Doppler flow measurements of the middle cerebral artery could be assessed in a mean time less than 2 min. CONCLUSION Emergency assessment of intracranial arteries using portable duplex ultrasound devices is feasible shortly after arrival at the patient's site.