Variability of acquisition phase of computed tomography angiography in acute ischemic stroke in a real-world scenario.

• Despite different technical equipment and examination protocols in the diagnostic workup of acute ischemic stroke, the total number of computed tomography angiography (CTA) with venous contrast was low (n = 13/871; 1.5%). • A higher venous than arterial contrast density at the level of the circle of Willis was not more frequent in CTAs from the centers with a high patient volume (comprehensive stroke center) compared to the hospital with lower patient volume (primary stroke centers). • Differences between the further differentiated contrast phases indicate that there is potential for further improvement of CTA acquisition protocols.