Nasr, Deena M.

Background: Ischemic stroke remains a leading cause of morbidity and mortality worldwide. Cardioembolic sources account for a significant proportion of these events, necessitating accurate identification of underlying structural heart abnormalities. Traditionally, transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) have been utilized for this purpose, although both have limitations. Cardiac computed tomography (CCTA) has emerged as a potential alternative, offering non-invasive imaging with high sensitivity and specificity for detecting intracardiac thrombi. Objective: This study aimed to evaluate the diagnostic yield of CCTA compared to TTE and TEE in detecting high-risk cardioaortic sources of embolism, including left ventricular (LV) thrombus, left atrial (LA) thrombus, valvular thrombus, and ulcerated aortic plaques, in patients with ischemic stroke. Methods: We conducted a retrospective, single-center cohort study at Mayo Clinic, Rochester, MN, including 426 ischemic stroke patients who underwent CCTA within 30 days of stroke onset between March 2019 and June 2023. We compared the diagnostic yields of CCTA, TTE, and TEE in detecting structural cardiac sources of embolism. Results: The overall diagnostic yield of CCTA for detecting high-risk cardioaortic sources was 15.5%. Specifically, CCTA identified LV thrombus in 2.3% of patients, LA thrombus in 4.0%, valvular thrombus in 2.8%, and ulcerated aortic plaques in 7.0%. In comparative analysis, CCTA demonstrated a higher yield than TTE (16.0% vs 3.5%, p < 0.001) and a comparable yield to TEE (25.3% vs 20.7%, p = 0.47) in detecting these sources. Conclusions: CCTA proved to be a viable option for identifying high-risk structural sources of cardioembolism in ischemic stroke patients. Its non-invasive nature, coupled with the ability to perform imaging soon after stroke onset, underscores its clinical utility. However, further prospective and blinded studies are required to validate these findings and fully establish the efficacy of CCTA in this context.

Background: Little is known about the association between intraplaque hemorrhage (IPH) and other features of high-risk carotid atherosclerotic plaques, such as the presence of plaque ulceration, plaque enhancement, and lipid-rich necrotic core (LRNC). This study set out to assess the relationship between IPH and other vulnerable plaque features. Materials and Methods: A retrospective review was done of 102 patients with IPH in one or both of the internal carotid arteries (ICA) on neck MRA between 1/1/2016 and 3/31/2021. IPH was defined as a ≥200% signal intensity of the adjacent sternocleidomastoid muscle on MPRAGE images. All ICA plaques were assessed for the presence or absence of IPH, plaque ulceration, plaque enhancement, and LRNC, as well as IPH volume. IPH volume was measured manually by outlining the region of interest. Results: A total of 102 patients were included, with 88 (86.3%) being male. The average age was 73.5 years (SD = 9.0). Both IPH and LRNC were more commonly seen in the left carotid artery ( p = .018 and p = .047, respectively). For right-sided ICAs, there was a significant association between IPH and LRNC ( p < .0001). Lesions without IPH were more likely to have plaque enhancement than lesions with IPH ( p = .04). For left-sided ICAs, there was also a significant association between the presence of IPH and LRNC ( p < .0001). Conclusions: There is a significant association between the presence of IPH and LRNC. An inverse relationship was found between the presence of IPH and plaque enhancement for right-sided plaques. No associations were found between IPH and plaque ulceration.

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.

Background Ischemic stroke remains a leading cause of morbidity and mortality worldwide. Understanding stroke etiology is critical in future stroke prevention. A cardioembolic etiology of stroke makes up a significant proportion of all ischemic stroke. Part of the evaluation for a cardioembolic etiology requires a structural evaluation of the heart to evaluate for sources of thrombus. Traditionally, transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) have been utilized for this purpose, although both have limitations. Cardiac computed tomography (CCT) has emerged as a potential alternative, offering non‐invasive imaging with high sensitivity and specificity for detecting intracardiac thrombi. This study aimed to evaluate the diagnostic yield of CCT compared to TTE and TEE in detecting high‐risk cardioaortic sources of embolism, including left ventricular (LV) thrombus, left atrial (LA) thrombus, valvular sources of thrombus, and ulcerated aortic plaques, in patients with ischemic stroke. Methods We conducted a retrospective, single‐center cohort study at Mayo Clinic, Rochester, MN, on patients who underwent CCT within 30 days of stroke onset between March 2019 and June 2023. We compared the diagnostic yields of CCT, TTE, and TEE in detecting structural cardiac sources of embolism. Results 426 patients were included in our study. 87 patients underwent both CCT and TEE, 257 underwent CCT and TTE, and 82 only underwent CCT. The overall diagnostic yield of CCT for detecting high‐risk cardioaortic sources was 15.5%. Specifically, CCT identified LV thrombus in 2.3% of patients, LA thrombus in 4.0%, valvular thrombus in 2.8%, and ulcerated aortic plaques in 7.0%. In comparative analysis, CCT demonstrated a higher yield than TTE (16.0% vs. 3.5%) and a comparable or higher yield than TEE (25.3% vs. 20.7%) in detecting these sources. Conclusions CCT proved to be a viable and potentially superior alternative to traditional echocardiography for identifying some high‐risk structural sources of cardioembolism in ischemic stroke patients. Its non‐invasive nature, coupled with the ability to perform imaging soon after stroke onset, underscores its clinical utility. However, further prospective and blinded studies are required to validate these findings and fully establish the efficacy of CCT in this context.