One in four cases of large vessel occlusion ischaemic stroke may be missed when only selected patients have CT angiography, US researchers say.

In 2017, doctors at the Henry Ford Health System in Detroit changed their policy to require all patients presenting at the ED within 24 hours of being ‘last known well’ to have the imaging, regardless of their National Institutes of Health Stroke Scale (NIHSS) score.

A requirement that serum creatinine should be checked before CT angiography was removed at the same time.

Prior to the introduction of the new policy, stroke patients only had CT angiography if they presented within six hours of last known well and had an NIHSS score of six or higher, the authors wrote in Stroke.