Benson, John C.

Carotid plaque vulnerability features beyond the degree of stenosis may play a key role in the pathogenesis and recurrence of ischemic cerebrovascular events. This study sought to compare intraplaque hemorrhage (IPH) as a marker of plaque vulnerability in symptomatic patients with mild (<50%), moderate (50%–69%), and severe (≥70%) carotid artery stenosis. We included patients who experienced ischemic cerebrovascular events with no other identifiable sources and underwent carotid endarterectomy for mild (n=32), moderate (n=47), and severe (n=58) carotid artery stenosis. The degree of stenosis and imaging hallmarks were assessed by computed tomography angiography or magnetic resonance angiography. Plaque specimens were stained with hematoxylin and eosin and Movat pentachrome staining. Carotid plaques of patients with mild stenosis had a higher extent of IPH (%) on tissue analysis compared with patients with moderate (mild, 15.7% [interquartile range, 7.8%–26.7%]; moderate, 3.9% [0.0%–9.2%]; P <0.001) and severe carotid artery stenosis (mild, 15.7% [interquartile range, 7.8%–26.7%]; severe, 2.5% [interquartile range, 0.0%–11.2%]; P <0.001). When considering the degree of carotid artery stenosis as a continuous variable, a lower lumen narrowing was associated with higher extent of IPH ( P <0.001; R, −0.329). Our major finding is the association of IPH with mild carotid artery stenosis based on histological analysis. The current study may suggest that IPH potentially plays a role in the mechanism of stroke in patients with nonobstructive carotid stenosis.

Background Little is known about the impact that cardiovascular (CV) risk factors have on the formation of various carotid atherosclerotic plaque features. This study set out to assess the association between CV risk factors and plaque characteristics on computed tomography (CT) angiography (CTA). Materials and methods A retrospective review was completed of consecutive patients that underwent a carotid endarterectomy and had CTA imaging of the head and neck vasculature. Atherosclerotic plaques of both carotid arteries were evaluated for calcification(s), low-density plaque (LDP) components, ulceration(s), and degree of stenosis. Various clinical CV risk factors were assessed using medical records. Last recorded laboratory levels were dichotomized into categories: total cholesterol <200 or ≥200 mg/dL, low-density lipoprotein (LDL) <130 or ≥130 mg/dL, high-density lipoprotein <35 or ≥35 mg/dL, and triglyceride <200 or ≥200 mg/dL. Results Of 97 included patients, 62 were male (63.9%); the average age was 72.7 (standard deviation = 9.5). Calcifications were in 95/97 (97.9%) of patients (one or both carotid plaques); LDP components were in 73/97 (75.3%), and ulcerations were in 21/97 (21.6%). Elevated total cholesterol and elevated LDL levels were both associated with a higher likelihood of LDP components ( p = 0.004 and p = 0.02, respectively). There were no other statistically significant associations between individual plaque features or severity of arterial stenosis and CV risk factors. Conclusion In carotid atherosclerotic plaques, LDP components are more frequently present in one or both carotid arteries in patients with elevated total cholesterol and/or LDL levels. Such findings raise the possibility that cholesterol levels may be directly related to the formation of specific high-risk plaque features.

Background Using computed tomography angiography to differentiate between components of carotid atherosclerotic lesions remains largely elusive. This study sought to validate a semi-automated software for computed tomography angiography plaque analysis using histologic comparisons. Materials and Methods A retrospective review was performed of consecutive patients that underwent a carotid endarterectomy, with pre-procedural computed tomography angiography imaging of the cervical arterial vasculature available for review. Images were evaluated using a commercially-available software package, which produced segmented analyses of intraplaque components (e.g. intraplaque hemorrhage, lipid-rich necrotic core, and calcifications). On imaging, each component was assessed in terms of its (1) presence or absence, and (2) both volume and proportion of the total plaque volume (if present). On histological evaluation of carotid endarterectomy specimens, each component was evaluated as an estimated proportion of total plaque volume. Results Of 80 included patients, 30 (37.5%) were female. The average age was 69.7 years (SD = 9.1). Based on imaging, intraplaque hemorrhage was the smallest contributor to plaque composition (1.2% of volumes on average). Statistically significant linear associations were noted between the proportion of intraplaque hemorrhage, lipid-rich necrotic core, and calcifications on histology and the volume of each component on imaging ( p values ranged from 0.0008 to 0.01). Area under curve were poor for intraplaque hemorrhage and lipid-rich necrotic core (0.59 and 0.61, respectively) and acceptable for calcifications (0.73). Conclusion Semi-automated analyses of computed tomography angiography have limited diagnostic accuracy in the detection of intraplaque hemorrhage and lipid-rich necrotic core in carotid artery plaques. However, volumetric imaging measurements of different components corresponded with histologic analysis.

Objective To systematically analyse prior reports of carotid endarterectomy (CEA) performed in cases of ≤50% carotid stenosis in order to understand patient tolerance and potential benefit. Methods A systematic review and descriptive analysis was performed in concordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. An English-language search was performed of online databases using librarian-selected search terms. Abstracts were reviewed for relevance which included mention of carotid endarterectomy and stenosis. Prospective or retrospective observational cohort studies that reported series of patients who underwent endarterectomy for minimal (≤50%) luminal stenosis with reported outcomes were included. Results Six studies (which included our institutional series) with a total of 143 patients met the inclusion criteria. The weighted mean age at the time of CEA was 72.3 years; 113 (79.0%) were male. 55.8% of patients with available data had recurrent ipsilateral ischaemic events despite medical therapy. Two patients out of 129 with available perioperative data (1.6%) had perioperative MRI findings of acute ischaemic stroke, both within the hemisphere contralateral to the side of CEA. Of the 138 patients with available follow-up (mean, 36 months), none had recurrent ipsilateral ischaemic events. Conclusions Endarterectomy for symptomatic carotid disease causing ≤50% stenosis may be a potentially beneficial strategy to prevent stroke recurrence. Studies with robust methodology are needed to draw more definitive conclusions in terms of the safety and efficacy of endarterectomy for minimal stenosis with vulnerable features relative to intensive medical therapy.

Purpose This study sought to validate whether the signal intensity ratio (SIR) of carotid intraplaque hemorrhage (IPH) was associated with acute ischemic neurologic events. Methods A retrospective review was completed of consecutive patients that underwent neck magnetic resonance angiography using magnetization prepared-rapid gradient echo (MP-RAGE) and T1-CUBE sequences between 2017 and 2020. Patients with magnetic resonance evidence of IPH were included. SIRs were measured by comparing the maximum IPH signal with the mean intramuscular signal from the adjacent sternocleidomastoid. Patients were stratified into ischemic or non-ischemic groups based on the presence of acute ipsilateral ischemic events (stroke, retinal artery occlusion). Logistic regression analysis was performed to determine if increasing IPH SIR was associated with an increased risk of ipsilateral ischemic events. Results Of 85 included patients (85 arteries), 66 were male (77.6%). Mean age was 71.0 (SD ± 11.1). There were 70 arteries with IPH that were ipsilateral to an ischemic event, and 15 that belonged to patients without an ischemic event. No association was found between increasing IPH SIR seen on MP-RAGE (odds ratio (OR): 0.82; 95% confidence interval (CI): 0.58–1.4; P = 0.43) or T1-CUBE sequences (OR: 0.85; 95% CI: 0.53–1.5; P = 0.56). Conclusions There was no association between the SIR of IPH and acute ischemia on either MP-RAGE or T1-CUBE sequences. Further investigation is required prior to widespread acceptance of SIR as a predictive imaging marker of symptomatic carotid plaque.

Background and Purpose: Leukoaraiosis is a poor prognostic marker for patients with acute ischemic stroke (AIS). This study sought to assess if severity of leukoaraiosis is associated with outcome in patients with AIS following endovascular thrombectomy, and to propose a leukoaraiosis-related modification to the ASPECTS score to improve its predictive value for good outcome. Methods: We analyzed consecutive patients with AIS that underwent mechanical thrombectomy for anterior circulation large vessel occlusion at our comprehensive stroke center. Leukoaraiosis burden was graded using the Fazekas scale (combined scores from two locations categorically divided into no leukoaraiosis (score = 0), mild (1-2), moderate (3-4) and severe (5-6)). The primary outcome measure was 90-day mRS. A proposed Leukoaraiosis-ASPECTS (“L-ASPECTS”) was calculated by subtracting values from the traditional ASPECT based on leukoaraiosis severity (1 point subtracted if mild, 2 if moderate, 3 if severe). Results: Of 174 included patients, 89 (51.2%) were female; average age was 68.0±9.1. 28 (16.1%) had no leukoaraiosis, 66 (37.9%) had mild, 62 (35.6%) had moderate, and 18 (10.3%) had severe. Leukoaraiosis severity was associated with worse 90-day mRS among all patients (p=0.0005) as well as those that were successfully revascularized (p=0.0002). A multivariate analysis confirmed that leukoaraiosis burden was associated with worse 90-day mRS among all patients (mild: p=0.006; moderate: p=0.002; severe: p=0.03), as well as those that underwent successful thrombectomies (p=0.005). Both L-ASPECTS and ASPECTS were associated with poor outcomes, but the association was stronger with L-ASPECTS (p<0.0001 and AUC=0.7 for L-ASPECTS; p=0.04 and AUC=0.59 for ASPECTS). Conclusion: Leukoaraiosis severity on pre-mechanical thrombectomy NCCT is associated with worse 90-day outcome in patients with AIS following endovascular recanalization, and is an independent risk factor for worse outcomes. A proposed L-ASPECTS score had stronger association with outcome than the traditional ASPECTS score.

Introduction There is increased interest in the use of artificial intelligence-based (AI) software packages in the evaluation of neuroimaging studies for acute ischemic stroke. We studied whether, compared to standard image interpretation without AI, Brainomix e-ASPECTS software improved interobserver agreement and accuracy in detecting ASPECTS regions affected in anterior circulation LVO. Methods We included 60 consecutive patients with anterior circulation LVO who had TICI 3 revascularization within 60 minutes of their baseline CT. A total of 16 readers, including senior neuroradiologists, junior neuroradiologists and vascular neurologists participated. Readers interpreted CT scans on independent workstations and assessed final ASPECTS and evaluated whether each individual ASPECTS region was affected. Two months later, readers again evaluated the CT scans, but with assistance of e-ASPECTS software. We assessed interclass correlation coefficient for total ASPECTS and interobserver agreement with Fleiss’ Kappa for each ASPECTS region with and without assistance of the e-ASPECTS. We also assessed accuracy for the readers with and without e-ASPECTS assistance. In our assessment of accuracy, ground truth was the 24 hour CT in this cohort of patients who had prompt and complete revascularization. Results Interclass correlation coefficient for total ASPECTS without e-ASPECTS assistance was 0.395, indicating fair agreement compared, to 0.574 with e-ASPECTS assistance, indicating good agreement (P < 0.01). There was significant improvement in inter-rater agreement with e-ASPECTS assistance for each individual region with the exception of M6 and caudate. The e-ASPECTS software had higher accuracy than the overall cohort of readers (with and without e-ASPECTS assistance) for every region except the caudate. Conclusions Use of Brainomix e-ASPECTS software resulted in significant improvements in inter-rater agreement and accuracy of ASPECTS score evaluation in a large group of neuroradiologists and neurologists. e-ASPECTS software was more predictive of final infarct/ASPECTS than the overall group interpreting the CT scans with and without e-ASPECTS assistance.

Background Diffuse intracranial susceptibility abnormalities have recently been described among patients with coronavirus disease 2019 (COVID-19), although prior studies have consisted of case reports and/or series. This brief literature review seeks to compile and catalogue the available data to elucidate characteristic features of such findings. Materials and methods Scientific articles and studies on intracranial microhemorrhages in the setting of COVID-19 were searched on PubMed, Google Scholar, and the Cochrane Library. Included studies described intracranial microbleed(s) on magnetic resonance imaging in patients with COVID-19. If multiple patients were described, only patients with intracranial microhemorrhage on magnetic resonance imaging were included for analysis. Patient demographics, severity of illness (e.g. intensive care unit admission and/or intubation), time from diagnosis of COVID-19 to magnetic resonance imaging, and location(s) of any observed microhemorrhages were noted. Results A total of 39 patients with suspected intracranial microhemorrhages have been described in prior studies. The average age of patients was 64.7 years; 21.9% were women. The average time between COVID-19 diagnosis and magnetic resonance imaging was 31.7 days. All patients in the cohort were admitted to critical care and were either intubated or treated with extracorporeal membrane oxygenation during their clinical course. Microhemorrhages were most commonly located in the subcortical/juxtacortical white matter and corpus callosum. Conclusions Intracranial microbleeds are a well-documented finding in patients with severe COVID-19, and are most commonly callosal and subcortical/juxtacortical in location.