Pahl, Emily

Introduction: AI-driven software has been recommended as a means of triaging suspected large vessel occlusions (LVOs) on CT angiography (CTA), and different solutions are now commercially available. This study compared the performance of two software packages, Brainomix 360 Triage LVO and Rapid LVO, in prospective, real-world use. Methods: Consecutive patients scanned for suspected stroke at 3 comprehensive stroke centres from May to July 2024 (3 months) were included in the study. CTA, where available, was processed in real time by both Rapid and Brainomix software. Ground truth on vessel occlusion was ascertained using clinical review of electronic medical records. Occlusion location was coded as intracranial internal carotid artery terminus (ICA-T), middle cerebral artery (MCA) M1 or MCA M2. If more than one occlusion was observed, the most proximal of these was taken as the primary vessel affected. Results: There were 561 suspected stroke patients scanned during the study period across the three sites. Of these, CTA was sent for processing by both Rapid LVO and Brainomix 360 Triage LVO for 359 cases. Cases were excluded if no contrast was detected (n=17), leaving 342 cases (Table 1). Of these, proximal LVO (ICA-T or MCA M1) was confirmed in 14 cases and MCA M2 occlusions were present in 6 cases. Table 2 shows the LVO detection results for all cases from the two software packages. For both devices, sensitivity was higher when considering only proximal occlusions (ICA-T or M1). Performance was similar overall, but there was a trend towards differing sensitivity for more distal occlusions. As a composite measure, area under the curve (AUC) was higher for Brainomix than Rapid (Figure 1) but this difference was not significant. The positive predictive value (PPV) was low for both software packages due to the low incidence of LVO in the patient population. Conclusions: This study demonstrated consistent performance of two AI software devices, Brainomix 360 Triage LVO and Rapid LVO, for detection of LVO on CTA imaging, in prospective, real-world use. The low number of positive cases in the dataset (N=21) is a limitation of the study. There was a trend towards different performance for more distal vessel occlusion locations. Overall, the sensitivity observed in this dataset was in line with reports from previous retrospective studies for both software packages and underlines the importance of prospective evaluation to understand real-world performance.

Background: Artificial intelligence (AI) stroke imaging software is becoming mainstay in many hub-and-spoke hospitals. Brainomix 360 Stroke software is the market leader in Europe focused on leveraging simple imaging (non-contrast computerized topography (NCCT) and CT angiography (CTA)) and has recently been FDA-cleared for use in the USA. We evaluated the implementation of Brainomix 360 AI Stroke software in the 17 spoke, multi-state Mayo Clinic Health System (MCHS) telestroke network. Methods: This prospective study compared decision and treatment times before and after Brainomix AI implementation, as well as clinician feedback and simulated decision making to better understand any changes seen. Patients were included if they underwent telestroke evaluation at an MCHS emergency department within 90 days of implementation (2/9/2024-8/8/2024), and excluded if they were already admitted to the hospital or if video evaluation was not performed. Data collection included demographics, clinical decisions and treatment times. Qualitative surveys were conducted at baseline and evaluation end, as well as simulated decision making in 20 de-identified cases randomized to with/without AI through an online portal. Results: A total of 907 patients were included (444 pre- and 463 post-implementation, 287 (32%) with ischemic stroke final diagnosis). Median NIHSS was 2. IVT was recommended in 20.3% (27/148 ischemic stroke patients) pre- and 25.9% (36/139) post-implementation. EVT was recommended in 16.2% (24/148) pre and 14.4% (20/139) post. AI use was associated with trends of faster telestroke activation to IVT decision (36 vs 32 mins, p=0.6), IVT administration (47 vs 40 minutes, p=0.6), and EVT decision (36 vs 33 minutes, p=0.5). In the simulation, imaging interpretation was significantly faster when randomized to AI use (3.4 vs 2.1 mins, p<0.001) and associated with improved physician confidence (62 vs 88%, p=0.004). Qualitative feedback from 14/24 neurologists showed the greatest perceived value was improved confidence of treatment decisions (43%) and faster triaging (36%). Most value was gained from e-ASPECTS (NCCT) and LVO modules. Conclusion: This service evaluation highlighted the opportunity to improve efficiency of decision making even in the setting of a well-developed telestroke system. The impact was underpinned by the improved speed and confidence of imaging interpretation reflected in an offline simulation and qualitative feedback.

Introduction: Central retinal artery occlusion (CRAO) is an under-recognized stroke subtype that may benefit from hyperacute reperfusion therapies. We aimed to evaluate the ability of telestroke activations to provide CRAO diagnosis and thrombolysis. Methods: This retrospective observational study investigates all encounters conducted for acute visual loss between 2010 and 2021 in our multicentric Mayo Clinic Telestroke Network. Demographics, time from visual loss to telestroke evaluation, ocular examination, diagnostic, and therapeutic recommendations were collected for CRAO subjects. Results: Out of 9,511, 49 encounters (0.51%) were conducted for an acute ocular complaint. Five patients had possible CRAO, and 4 presented within 4.5 h from symptom onset (range 1.5–5 h). None received thrombolytic therapy. All telestroke physicians recommended ophthalmology consultation. Conclusion: Current telestroke assessment of acute visual loss is suboptimal and patients eligible for acute reperfusion therapies may not be offered treatment. Teleophthalmologic evaluations and advanced ophthalmic diagnostic tools should complement telestroke systems.

Introduction: Central retinal artery occlusion (CRAO) is a neurovascular emergency and acute monocular visual loss should trigger a stroke code activation. As thrombolytic therapy is considered for non-arteritic CRAO in the stroke therapeutic window, we aimed to review all telestroke encounters for acute visual loss in Mayo Clinic national telestroke network, focusing on the ocular diagnosis and the management recommendations. Hypothesis: patients evaluated via telestroke for acute visual loss are less likely to receive thrombolysis Methods: We conducted a retrospective review of the Mayo Clinic Arizona Telestroke/Teleneurology (2010-2017, 6364 encounters) and Mayo Clinic Enterprise Telestroke databases (2018-2020, 3147 encounters), searching for visits requested for acute visual loss. We recorded the subjects’ demographics, time from last seen normal to telestroke evaluation, preliminary diagnosis, and therapeutic/diagnostic recommendation. Results: From a total of 9511 audio-video telestroke encounters, 49 (0.51%) had an ocular diagnosis. Out of those, 6 patients (12.2%) had a provisional diagnosis of CRAO. 4/6 (66.6%) CRAO patients presented within 4.5h from symptom onset (median 2 hours) and none received thrombolytic therapy. All telestroke physicians recommended antiplatelet, ophthalmology consultation for diagnostic evaluation and comprehensive stroke work-up. Conclusions: Telestroke evaluations for CRAO, in routine practice, are less common than the disease prevalence would predict, suggesting that education is urgently mandated to increase the index of awareness. Even when CRAO subjects are evaluated via telestroke within 4.5 hours from symptom onset, they do not receive thrombolytic therapy nor timely ophthalmologic evaluation. Telestroke visits may benefit from the inclusion of tele-ophthalmologic consults to help with establishing the diagnosis in the narrow time-window of intravenous thrombolysis.