Background Neurovascular imaging for patients with high-risk transient ischemic attack (TIA) or minor stroke in the emergency department (ED) with computed tomography angiography (CTA) of the head and neck is the guideline-recommended standard of care, but it is underutilized in routine practice. We conducted a quality initiative to improve adherence to guidelines. Methods Between January 2017 and March 2019, we implemented a decision support tool integrated into the electronic ordering system to guide ED physicians to order a CTA on patients with high-risk TIA or minor stroke defined as ongoing neurological deficits in the ED or resolved motor or speech deficits in the preceding 48 h. Data were collected retrospectively pre-intervention and prospectively post-intervention. We used an interrupted time-series analysis for the before-after comparison of the use of CTA among patients who met criteria (main process measure) and those who did not meet criteria (balancing measure). Results Among 861 patients with TIA or minor stroke, the proportion of patients with high-risk events imaged with a CTA in the ED increased from 12.0% pre-intervention to 77.0% post-intervention and this shift was sustained over 11 months. CTA use in those without high-risk events increased to a lesser extent (15.3% versus 42.9%). The interrupted time-series analysis showed a step change immediately post-intervention where the increase in CTA use in patients with high-risk events was 51.7% higher than its use in those without high-risk events (p < 0.001). Compared to pre-intervention, the median ED length of stay increased by 2 h and neurology consultation in the ED was more frequent (5.8% versus 19.5%) post-intervention. ConclusionWe provide a detailed framework that improved adherence to acute imaging guidelines for patients with TIA or minor stroke and anticipate that our approach could improve acute imaging for such patients in most EDs. Keywords Quality improvement • Transient ischemic attack • Stroke • ImagingRésumé Contexte L'imagerie neurovasculaire pour les patients présentant un risque élevé d'accident ischémique transitoire (AIT) ou d'accident vasculaire cérébral mineur aux services d'urgence, avec une angiographie par tomodensitométrie (CTA) de la tête et du cou, est la norme de soins recommandée par les directives, mais elle est sous-utilisée dans la pratique courante. Nous avons mené une initiative de qualité pour améliorer le respect des lignes directrices.