Interventions
stroke, emergent stroke
STROKE, EVENTS
At the start of the trial period, noncontrast CT and CTA acquisition protocols were modified such that all imaging performed in the workup of patients presenting to the emergency departments for possible AIS was automatically transmitted to a cloud-based AI algorithm trained to detect LVO AIS from CTA (Viz.AI). This software package analyzes CTA images and arrives at a decision on the presence or absence of LVO within several minutes of receiving images. This software has been previously validated and shown to have high sensitivity and accuracy for LVO detection.Software implementation strategies were identical across all sites. At the start of the study period, communication was sent to all the clinicians, radiologists, radiology technicians, and stroke care team members of the upcoming intervention. After the information technology security review had been completed, team members from the vendor then began working with CT technologists to modify CT acquisition protocols such that images would be sent at the time of acquisition to the cloud-based AI server. This process began at all sites at the start of the study period but increased in intensity closer to each sites’ activation. Weekly team meetings occurred between representatives from the vendor and a team consisting of each campus’s stroke coordinators and lead members from neurology, radiology, emergency medicine, neurointervention, and nursing to monitor progress. Two to 3 weeks prior to activation, a team of representatives from the vendor traveled in-person to the campus and hosted 2 days of education for the physicians and staff of the site. The purpose of these events was to remind the local team of the upcoming activation, demonstrate how to download and log in to the software, trouble shoot any other technical difficulties with software access, and send test images from the CT scanners to the cloud-based AI server to ensure that this process was functioning optimally. On the day of activation, additional notifications were sent to the hospital stroke team members to inform them of the change.The 4 CSCs shared some similarities but also had differences. One CSC (CSC 4) was a major academic hub, with residents, fellows, and other trainees. Two other CSCs (CSCs 1 and 3) also had trainees but fewer in number. The four CSCs differed in annual AIS volume, as well as EVT volume as discussed below. During this study period, 2 CSCs (CSCs 1 and 4) also participated in large core EVT trials as discussed above. They were identical, however, with respect to electronic medical record system, stroke evaluation order sets, stroke evaluation protocols, institutional guidelines on EVT treatment eligibility, and image viewing systems. All CSCs had neurointensive care units and modern endovascular equipment with dedicated neurointerventional physician, nurse, and technologist teams. During daytime hours, all emergent stroke evaluations were performed by in-house physicians, including weekends. At nighttime, telemedicine was used. This system was consistent across all 4 CSCs. Some physicians rotated between the 4 sites, but most staff at each hospital were specific to that campus. For full study protocol, see 