The hyperdense artery sign could be an early indication of an ischemic stroke secondary to an embolic occlusion of the corresponding artery.
This patient presented with an acute onset of left hemiparesis and altered mental status. A CT head without contrast showed a hyperdense basilar artery (yellow arrow in A and C), indicating embolic thrombus. This hyperdense sign was even more convincing since the patient had an old CT head (B and D) to compare with. Due to a contrast allergy, no CTA head was obtained at the OSH. The patient was subsequently intubated, and DSA confirmed the basilar occlusion (E and F). Mechanical thrombectomy yielded a TICI 2B reperfusion.