Etiology and characteristics of non-aneurysmal thunderclap headache presenting to an acute setting.

OBJECTIVES: To describe the characteristics and causes of non-aneurysmal thunderclap headache (TCH) and compare serious from benign underlying causes. METHODS: Retrospective cohort study of consecutive adult patients with TCH presenting to a tertiary care academic medical center between 2010 and 2020. Aneurysmal subarachnoid hemorrhage cases were excluded. Cases were categorized into serious or benign; serious TCH was defined as any condition in which delayed diagnosis and treatment could result in neurological disability or death. Risk factors for serious TCH were analyzed. We adhere to standardized guidelines for reporting observational studies. RESULTS: A total of 932 patients presented with TCH. After exclusion of 393 patients with aneurysmal-type subarachnoid hemorrhage, 539 were included in the analysis. One-half (n = 275, 51.0 %) had a serious cause. Median age was 51 years, 69.0 % were female. Most frequent diagnoses were intracranial hemorrhage (n = 102, 18.9 %), reversible cerebral vasoconstriction syndrome (n = 97, 18.0 %), and idiopathic TCH (n = 102, 38.6 %). A multivariable logistic regression model for prediction of serious TCH included age, hypertension, migraines, recurrent TCH, level of consciousness and other clinical exam findings, and achieved an AUROC of 0.732. This score had a sensitivity of 79.9 % (95 % CI 73.5-83.5 %) for the identification of serious TCH. A 0.5-point increase in the risk score was associated with a 73 % increase in the odds of serious TCH (odds ratio 1.73, 95 % CI 1.53-1.95, p < 0.001). CONCLUSION: Our study describes the relative frequency of presentation and etiologies among patients with TCH This score can aide clinicians in recognising patients with potentially serious cause of TCH, for whom additional imaging and neurological consultation is necessary.

Serum Neurofilament to Magnetic Resonance Imaging Lesion Area Ratio Differentiates Spinal Cord Infarction From Acute Myelitis.

BACKGROUND AND PURPOSE: The diagnosis of spontaneous spinal cord infarction (SCI) is limited by the lack of diagnostic biomarkers and MRI features that often overlap with those of other myelopathies, especially acute myelitis. We investigated whether the ratio between serum neurofilament light chain levels and MRI T2-lesion area (neurofilament light chain/area ratio-NAR) differentiates SCI from acute myelitis of similar severity. METHODS: We retrospectively identified Mayo Clinic patients (January 1, 2000-December 31, 2019) with (1) SCI, (2) AQP4 (aquaporin 4)-IgG or MOG (myelin oligodendrocyte glycoprotein)-IgG-associated myelitis at disease clinical presentation, or (3) idiopathic transverse myelitis from a previously identified population-based cohort of patients seronegative for AQP4-IgG and MOG-IgG. Serum neurofilament light chain levels (pg/mL) were assessed at the Verona University (SIMOA, Quanterix) in a blinded fashion on available stored samples obtained ≤3 months from myelopathy presentation. For each patient, the largest spinal cord lesion area (mm2) was manually outlined by 2 independent raters on sagittal T2-weighted MRI images, and the mean value was used to determine NAR (pg/[mL·mm2]). RESULTS: Forty-eight patients were included SCI, 20 (definite, 11; probable, 6; possible, 3); acute myelitis, 28 (AQP4-IgG-associated, 17; MOG-IgG-associated, 5; idiopathic transverse myelitis, 6). The median expanded disability status scale score (range) at myelopathy nadir were 7.75 (2-8.5) and 5.5 (2-8), respectively. Serum neurofilament light chain levels (median [range] pg/mL) in patients with SCI (188 [14.3-2793.4]) were significantly higher compared with patients with AQP4-IgG-associated myelitis (37 [0.8-6942.9]), MOG-IgG-associated myelitis (45.8 [4-283.8]), and idiopathic transverse myelitis (15.6 [0.9-217.8]); P=0.01. NAR showed the highest accuracy for identification of SCI versus acute myelitis with values ≥0.35 pg/(mL·mm2) yielding 86% specificity and 95% sensitivity (area under the curve=0.93). The positive and negative likelihood ratios were 6.67 and 0.06, respectively. NAR remained independently associated with SCI after adjusting for age, gender, immunotherapy before sampling, and days from myelopathy symptoms onset to sampling (P=0.0007). CONCLUSIONS: NAR is a novel and promising clinical biomarker for differentiation of SCI from acute myelitis.

Outcomes following surgical versus endovascular treatment of spinal dural arteriovenous fistula: a systematic review and meta-analysis.

Although surgical resection is associated with a complete cure in most cases of spinal dural arteriovenous fistulas (SDAVF), there has been an increasing trend towards embolisation. We performed a systematic review and meta-analysis comparing surgical resection with endovascular treatment in terms of success of treatment, rate of recurrence and complications. A literature search was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Strength of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation Working Group system. Surgical outcomes such as initial treatment failure, late recurrence, neurological improvement and complications were compared between the two approaches. We included 57 studies with 2029 patients, of which 32 studies with 1341 patients directly compared surgery (n=590) and embolisation (n=751). Surgery was found to be associated with significantly lower odds of initial treatment failure (OR: 0.15, 95% CI 0.09 to 0.24, I2 0%, p<0.001) and late recurrence (OR 0.18, 95% CI 0.09 to 0.39, I2 0%, p<0.001). The odds of neurological improvement following surgery were also significantly higher compared with embolisation alone (OR: 2.73, CI:1.67 to 4.48, I2 :49.5%, p<0.001). No difference in complication rates was observed between the two approaches (OR 1.78, 95% CI 0.97 to 3.26, I2 0%, p=0.063). Onyx was associated with significantly higher odds of initial failure/late recurrence as compared with n-butyl 2-cyanoacrylate (OR: 3.87, CI: 1.73 to 8.68, I2 :0%, p<0.001). Surgery may be associated with superior outcomes for SDAVFs in comparison to endovascular occlusion. Newer embolisation agents like Onyx have not conferred a significant improvement in occlusion rate.

Natural History of Vertebrobasilar Dolichoectatic and Fusiform Aneurysms: A Systematic Review and Meta-Analysis.

BACKGROUND AND PURPOSE: Vertebrobasilar non-saccular and dolichoectatic aneurysms (VBDA) are a rare type of aneurysm and are generally associated with poor prognosis. In order to better characterize the natural history of VBDAs, we performed a systematic review and meta-analysis of the literature to determine rates of mortality, growth, rupture, ischemia, and intraparenchymal hemorrhage. MATERIALS AND METHODS: We searched the literature for longitudinal natural history studies of VBDA patients reporting clinical and imaging outcomes. Studied outcomes included annualized rates of growth, rupture, ischemic stroke, intracerebral hemorrhage (ICH), and mortality. We also studied the association between aneurysm morphology (dolichoectatic versus fusiform) and natural history. Meta-analysis was performed using a random-effects model using summary statistics from included studies. RESULTS: Fifteen studies with 827 patients and 5,093 patient-years were included. The overall annual mortality rate among patients with VBDAs was 13%/year (95% CI 8-19). Patients with fusiform aneurysms had a higher mortality rate than those with dolichoectatic aneurysms, but this did not reach statistical significance (12 vs. 8%, p = 0.11). The overall growth rate was 6%/year (95% CI 4-13). Patients with fusiform aneurysms had higher growth rates than those with dolichoectatic aneurysms (12 vs. 3%, p < 0.0001). The overall rupture rate was 3%/year (95% CI 1-5). Patients with fusiform aneurysms had higher rupture rates than those with dolichoectatic aneurysms (3 vs. 0%, p < 0.0001). The overall rate of ischemic stroke was 6%/year (95% CI 4-9). Patients with dolichoectatic aneurysms had higher ischemic stroke rates than those with fusiform aneurysms, but this did not reach statistical significance (8 vs. 4%, p = 0.13). The overall rate of ICH was 2%/year (95% CI 0-8) with no difference in rates between dolichoectatic and fusiform aneurysms (2 vs. 2%, p = 0.65). CONCLUSION: In general, the natural history of -VBDAs is poor. However, dolichoectatic and fusiform -VBDAs appear to have distinct natural histories with substantially higher growth and rupture associated with fusiform aneurysms. These findings suggest that these aneurysms should be considered separate entities. Further studies on the natural history of vertebrobasilar dolichoectatic and fusiform aneurysms with more complete follow-up are needed to better understand the risk factors for progression of these aneurysms.

Pulmonary Arteriovenous Malformations Are Associated with Silent Brain Infarcts in Hereditary Hemorrhagic Telangiectasia Patients.

BACKGROUND AND PURPOSE: There is a high prevalence of right-to-left shunting pulmonary arteriovenous malformations (PAVMs), which are stroke risk factors, in hereditary hemorrhagic telangiectasia (HHT) patients. While the prevalence of ischemic complications in HHT patients is known, the prevalence of silent brain infarcts (SBI) remains unknown. The purpose of this study was to determine the prevalence and risk factors for SBI in HHT patients. MATERIALS AND METHODS: Our institutional HHT database was queried to identify HHT patients who received a baseline screening brain MRI from January 2000 to February 2017. This study group was further refined by excluding patients who had a history of clinical ischemic disease as defined by having a stroke or transient ischemic attack (TIA). Brain MRIs were reviewed for SBI. Baseline data on demographics, Curacao criteria, presence of PAVMs, and cardiovascular risk factors were collected. The primary outcome was SBI prevalence. We also examined which baseline patient characteristics were associated with SBI through univariate chi-square and Student t tests and multivariate logistic regression analyses. RESULTS: Three hundred fifty three consecutive HHT patients from January 2000 to February 2017 with a screening brain MRI and no prior history of stroke/TIA were included. SBI prevalence was 9.9% (35/353). SBI patients were more likely to have PAVMs than non-SBI patients (80.6 vs. 53.1%, p = 0.005). The median age was 66 in the SBI group and 52 in the non-SBI group (p = 0.006). SBI patients had higher prevalence of hyperlipidemia (34.3 vs. 9.8%, p < 0.0001), hypertension (48.6 vs. 22.0%, p = 0.005), and tobacco use (25.7 vs. 9.8%, p = 0.005). No patients under 30 had SBI. In the 60-69 age group, the prevalence of SBI was 18.8% with rates of 28.6% in the PAVM group and 10.5% in the non-PAVM group. For patients ≥70 years old, the prevalence of SBI was 21.4% overall and 27.6% in the PAVM group and 10.5% in the non-PAVM group. On multivariate analysis, PAVMs (OR 3.62, 95% CI 1.46-10.40) and increasing age (OR 1.04, 95% CI 1.01-1.07) were independently associated with SBI. CONCLUSIONS: Overall, a similar 10% SBI prevalence in the HHT cohort was noted as compared to the general population. However, the prevalence of SBI was higher in HHT patients with PAVMs when compared to that of the general population, particularly among patients than 60 years old. These findings highlight the need to accurately identify, and when appropriate, treat PAVMs in the HHT population especially given the multiple significant, clinical consequences of SBI.

Acute Brain Diseases as Triggers for Stress Cardiomyopathy: Clinical Characteristics and Outcomes.

OBJECTIVE: To determine the clinical characteristics and outcomes of patients with neurogenic stress cardiomyopathy (NSC) among patients admitted to our neuroscience intensive care unit (NICU). METHODS: Following institutional review board approval, consecutive adult patients admitted to the NICU between 2009 and 2013 with definite and possible NSC were included. Data on patient demographics, baseline clinical information, cardiac function, and laboratory values were collected. Outcomes included length of stay, modified Rankin Scale (mRS) at discharge and long-term follow-up. Continuous variables were compared using a student's t test, and categorical variables were compared using a Chi-square test. RESULTS: Among 34 patients included in the study, the most common presenting symptom was dyspnea (17 patients, 50%). Subarachnoid hemorrhage (SAH) was the most common neurological inciting event (11 patients, 32.4%), but two-thirds of this cohort had other neurological triggers. The most common electrocardiogram changes were QT-interval prolongation (30 patients, 88.2%) and T-wave inversion (22 patients, 64.7%). The most common echocardiographic pattern was the apical variant (14 patients, 41.2%), and 26% of patients had right ventricular involvement (P = 0.03) which was a predictor of poor outcome along with inotropic support (P = 0.006). Functional outcome was poor (mRS > 3) in 53% of patients at discharge, but function improved over time in most survivors. CONCLUSIONS: NSC is most common after SAH, but can result from a wide spectrum of acute brain insults. Requirement of inotropic support was the strongest indicator of prognosis at last follow-up. Patients with NSC often have poor function at discharge but many improve over time.

Dual-Energy CT to Diagnose Pseudoedema in Contrast-Induced Encephalopathy Following Cerebral Angiography.

BACKGROUND: Contrast-induced encephalopathy (CIE) is a syndrome that may be clinically unrecognized and misdiagnosed as cerebral edema. METHODS: Case report and review. RESULTS: A 72-year-old woman was admitted for elective endovascular embolization of a 10-mm left anterior communicating artery aneurysm. One hour post-procedure, she acutely developed global aphasia. Emergent head computed tomography (CT) and computed tomography-angiography (CTA) showed high attenuation of the left hemispheric subarachnoid spaces interpreted as hemispheric edema; emergent magnetic resonance imaging revealed left hemispheric punctate infarcts. At 12 h, she developed right hemiparesis and encephalopathy. Repeat CTA and CT perfusion revealed decreased left hemisphere cerebral blood flow and diminutive caliber of distal left middle cerebral artery territory vasculature. Repeated angiography with intra-arterial verapamil and systemic blood pressure augmentation were performed for presumed vasospasm. At 20 h, head CT was concerning for worsening left hemispheric edema, but dual-energy, iodine-subtracting sequences revealed significant contrast extravasation contributing to the appearance of sulcal effacement but without actual edema. Out of concern for blood-brain barrier breakdown from CIE, pressor augmentation was discontinued and the patient gradually improved to full neurological recovery within 72 h of symptom onset. CONCLUSIONS: Our case is the first known to report the use of dual-energy, iodine-subtracting CT as a diagnostic tool in differentiating between cerebral edema and pseudoedema in CIE.

Imaging Characteristics of Growing and Ruptured Vertebrobasilar Non-Saccular and Dolichoectatic Aneurysms.

BACKGROUND AND PURPOSE: Vertebrobasilar, nonsaccular, and dolichoectatic aneurysms generally have a poor natural history. We performed a study examining the natural history of vertebrobasilar, nonsaccular, and dolichoectatic aneurysms receiving serial imaging and studied imaging characteristics associated with growth and rupture. METHODS: We included all vertebrobasilar dolichoectatic, fusiform, and transitional aneurysms with serial imaging follow-up seen at our institution over a 15-year period. Two radiologists and a neurologist evaluated aneurysms for size, type, mural T1 signal, mural thrombus, daughter sac, mass effect, and tortuosity. Primary outcomes were aneurysm growth or rupture. Univariate analysis was performed with chi-squared tests for categorical variables and Student's t test or analysis of variance for continuous variables. Multivariate logistic regression analysis was performed to identify variables independently associated with aneurysm growth or rupture. RESULTS: One hundred and fifty-two patients with 542 patient-years (mean 3.6±3.5 years) of imaging follow-up were included. Aneurysms were fusiform in 45 cases (29.6%), dolichoectatic in 75 cases (49.3%), and transitional in 32 cases (21.1%). Thirty-five aneurysms (23.0%) grew (growth rate=6.5%/year). Eight aneurysms (5.3%) ruptured (rupture rate=1.5%/year). Variables associated with growth and rupture on univariate analysis were size >10 mm (57.6% versus 16.0%, P<0.0001), mural T1 signal (39.7% versus 16.3%, P=0.001), daughter sac (56.3% versus 21.3%), and mural thrombus (45.5% versus 13.4%, P<0.0001). 26.7% of fusiform aneurysms, 9.3% of dolichoectatic aneurysms, and 59.4% of transitional aneurysms grew or ruptured (P<0.0001). The only variable independently associated with rupture was transitional morphology (P=0.003). CONCLUSIONS: Vertebrobasilar, nonsaccular, and dolichoectatic aneurysms are associated with a poor natural history with high growth and rupture rates. Further research is needed to determine the best treatments for this disease.

Management of Unruptured Intracranial Aneurysms.

Unruptured intracranial aneurysms (UIA) occur in approximately 2-3 % of the population. Most of these lesions are incidentally found, asymptomatic and typically carry a benign course. Although the risk of aneurysmal subarachnoid hemorrhage is low, this complication can result in significant morbidity and mortality, making assessment of this risk the cornerstone of UIA management. This article reviews important factors to consider when managing unruptured intracranial aneurysms including patient demographics, comorbidities, family history, symptom status, and aneurysm characteristics. It also addresses screening, monitoring, medical management and current surgical and endovascular therapies.

Prognostic and Mechanistic Factors Characterizing Seizure-Associated Crossed Cerebellar Diaschisis.

BACKGROUND: Crossed cerebellar diaschisis is a rare finding of hemispheric cerebellar depression following contralateral cerebral injury, hypothesized to result from excessive neuronal excitatory synaptic activity along cortico-pontine-cerebellar pathways. The phenomenon is typically observed following ischemic stroke, but has also been characterized during seizure activity--in particular, status epilepticus (SE). Neurological outcome has varied widely in published reports, with some patients achieving full neurologic recovery, while others experience persistent disability. METHODS: Case report and literature review. RESULTS: We present a 54-year-old man found unresponsive with a right hemispheric syndrome several days after discharge following amygdalohippocampectomy for refractory right temporal lobe epilepsy. Prolonged electroencephalogram demonstrated one subclinical right frontal seizure, along with right frontal periodic lateralized epileptiform discharges, presumed to be associated with SE preceding his admission. Initial MRI demonstrated restricted diffusion on diffusion weighted imaging in the right cerebral hemisphere, ipsilateral thalamus, and contralateral cerebellum. A head CT one week later showed diffuse sulcal effacement with loss of gray-white differentiation in the right frontal and insular regions with low attenuation changes of right thalamus. An MRI showed worsened diffusion restriction, despite a corresponding increase in perfusion. The patient remained paretic at discharge and follow-up. Follow-up MRI at 2 months demonstrated pronounced right cerebral and left cerebellar atrophy, loss of gray matter in much of the right cerebrum, and scattered areas of T2 hyperintensity, consistent with permanent right fronto-temporal neuronal loss. CONCLUSIONS: Collectively, these observations indicate that imaging findings of persistent cerebral restricted diffusion and cytotoxic edema in the subacute post-ictal period may predict irreversible neuronal injury and poor long-term outcome-even when accompanied by evidence of cortical hyperperfusion and recovery of second- and third-order neurons along the involved circuit.

Moving From Alteplase to Tenecteplase for Acute Ischemic Stroke: Mayo Clinic Experience.

OBJECTIVES: Tenecteplase is a fibrin-specific plasminogen activator that has shown promising results in the treatment of acute ischemic stroke. Tenecteplase has been suggested to reduce door-to-needle time and to increase the rate of spontaneous recanalization. In February 2021, Mayo Clinic Health System switched to Tenecteplase as the standard thrombolytic therapy for acute ischemic stroke. METHODS: In this center-based observational cohort study, we present clinical characteristics and outcomes of patients with acute ischemic stroke treated with tenecteplase between February 2021 and May 2022 compared with alteplase treatment between September 2019 and February 2021. We used descriptive and comparative statistics. RESULTS: Baseline characteristics were comparable between the groups. The incidence of symptomatic intracerebral hemorrhage was significantly less among the tenecteplase group (0.65% vs. 5%, P =0.027). Both groups had a similar door-to-needle time [55 (IQR 30.5) vs. 57 (IQR 38) in the tissue plasminogen activator group, P =0.395]. Spontaneous partial or complete recanalization was more commonly observed in the tenecteplase group (10.4% vs. 1.4%, P =0.038). Mechanical thrombectomy for large vessel occlusion was deferred due to marked clinical improvement more commonly in tenecteplase (6.3% vs. 1.4%); however, this difference was not statistically significant. Ninety-day modified Rankin Scale did not show a significant difference between the groups. CONCLUSION: Tenecteplase use as the thrombolytic agent in acute ischemic stroke was associated with lower rates of symptomatic intracranial hemorrhage, higher rates of spontaneous recanalization, but similar door-to-needle time and 90-day modified Rankin Scale as compared with tissue plasminogen activator.

Cardiac CT vs Echocardiography for Intracardiac Thrombus Detection in Ischemic Stroke: A Systematic Review and Meta-Analysis of 43 Studies.

BACKGROUND AND OBJECTIVES: Ischemic stroke, a leading cause of mortality, necessitates understanding its mechanism for effective prevention. Echocardiography, especially transesophageal echocardiography (TEE), is the gold standard for detection of cardiac sources of stroke including left atrial thrombus, although its invasiveness, operator skill dependence, and limited availability in some centers prompt exploration of alternatives, such as cardiac CT (CCT). We conducted a systematic review and meta-analysis assessing the ability of CCT in the detection of intracardiac thrombus compared with echocardiography. METHODS: We searched 4 databases up through September 8, 2023. Major search terms included a combination of the terms "echocardiograph," "CT," "TEE," "imaging," "stroke," "undetermined," and "cryptogenic." The current systematic literature review of the English language literature was reported in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines. We assessed risk of bias using the QUADAS-2 tool and used random-effects meta-analysis to calculate different diagnostic metrics. RESULTS: The meta-analysis investigating CCT vs echocardiography for intracardiac thrombus detection yielded a total of 43 studies of 9,552 patients. Risk-of-bias assessment revealed a predominantly low risk of bias in the flow and timing, index test, and patient selection domains and a predominantly unclear risk of bias in the reference standard domain. The analysis revealed an overall sensitivity of 98.38% (95% CI 89.2-99.78) and specificity of 96.0% (95% CI 92.55-97.88). Subgroup analyses demonstrated that delayed-phase, electrocardiogram-gated CCT had the highest sensitivity (100%; 95% CI 0-100) while early-phase, nongated CCT exhibited a sensitivity of 94.31% (95% CI 28.58-99.85). The diagnostic odds ratio was 98.59 (95% CI 44.05-220.69). Heterogeneity was observed, particularly in specificity and diagnostic odds ratio estimates. DISCUSSION: CCT demonstrates high sensitivity, specificity, and diagnostic odds ratios in detecting intracardiac thrombus compared with traditional echocardiography. Limitations include the lack of randomized controlled studies, and other cardioembolic sources of stroke such as valvular disease, cardiac function, and aortic arch disease were not examined in our analysis. Large-scale studies are warranted to further evaluate CCT as a promising alternative for identifying intracardiac thrombus and other sources of cardioembolic stroke.

Racial and ethnic disparities in the use of intravenous recombinant tissue plasminogen activator and outcomes for acute ischemic stroke.

Racial and ethnic disparities in acute stroke care in the United States have been previously reported. This study investigated possible racial and ethnic disparities in the administration and outcome of recombinant tissue plasminogen activator (rtPA) therapy for acute ischemic stroke in whites, blacks, Hispanics, and Asian/Pacific Islanders. Using the National Inpatient Sample for 2001-2008, we selected patients with a primary diagnosis of acute ischemic stroke who received treatment with rtPA. Patient data were stratified by race (white, black, Hispanic, and Asian/Pacific Islander). We analyzed the association of patient race on rtPA utilization rate, in-hospital morbidity (ie, discharge to long-term facility), intracranial hemorrhage (ICH) rate, and in-hospital mortality. We performed a multivariate logistic regression analysis to determine independent predictors of poor outcomes. White patients had a higher rate of tPA utilization than black and Hispanic patients (2.3% vs 1.8% and 2.0%, respectively; P < .0001 for both groups). There was no difference in the rate of tPA utilization between whites and Asian/Pacific Islanders (2.3% vs 2.2% P = .07). Multivariate analysis of morbidity, mortality, and ICH rates found that Asian/Pacific Islanders had significantly higher rates of mortality (odds ratio, 1.22, 95% confidence interval, 1.03-1.44; P = .02) and ICH (odds ratio, 2.01; 95% confidence interval, 1.91-2.11; P < .0001) compared with whites. rtPA utilization was greater in white and Asian/Pacific Islander patients than in black and Hispanic patients. Asian/Pacific Islander race was associated with increased risk of ICH and mortality after rtPA administration.

The incidence of medium vessel occlusions: a population-based study.

Introduction: The incidence of medium vessel occlusion (MeVO) is not well known. The objective of our study is to perform a population-based assessment to estimate the incidence of MeVOs. Methods: Consecutive patients from Olmsted County, Minnesota who presented for acute ischemic stroke seen at Mayo Clinic Hospital from 1/1/2018 to 12/31/2020 who were found to have a MeVO were included in this study. MeVO was defined as occlusion at or beyond the level of the middle cerebral artery M2 segment, anterior cerebral artery A2 segment, posterior cerebral artery P1 segment, and cerebellar arteries. Census data for Olmsted County was obtained from the United States Census Bureau from the year 2020. Results: A total of 1,718 patients were screened for the study, 77 patients fulfilled inclusion criteria to be included in the study. Presenting NIHSS was 9 (± 7). The population of Olmsted County was estimated to be 162,847. The incidence rate for MeVO was 16 cases (95% CI 12-19) per 100,000 people per year. Based on estimates of the US population in 2020 of 331,449,281 people, we estimate there are 52,236 (95% CI 40,635-64,002) new cases of MeVOs per year. Conclusion: As the only stroke center in Olmsted County, we have been able to estimate the incidence of ischemic stroke due to MeVO. While the incidence of MeVOs is less than both large and small vessel occlusions, they still represent a significant proportion of strokes with significant morbidity and mortality that would benefit from further studies in both acute intervention and prevention.

Intraplaque hemorrhage on magnetic resonance angiography: How often do signal abnormalities persist on follow-up imaging?

BACKGROUND AND PURPOSE: Intraplaque hemorrhage (IPH) in carotid atherosclerosis demonstrates increased signal on magnetic resonance angiography images. Little remains known about how this signal changes on subsequent examinations. MATERIALS AND METHODS: A retrospective observational study was completed of patients that had IPH on a neck MRA between 1/1/2016 and 3/25/2021, defined as ≥ 200 % signal intensity of the sternocleidomastoid muscle on MPRAGE images. Examinations were excluded if the patients had undergone carotid endarterectomy between examinations or had poor quality imaging. IPH volumes were calculated by manually outlining IPH components. Up to 2 subsequent MRAs, if available, were assessed for both the presence and volume of IPH. RESULTS: 102 patients were included, of which 90 (86.5 %) were male. IPH was on the right in 48 patients (average volume = 174.0 mm3), and on the left in 70 patients (average volume 186.9 mm3). 22 had at least one follow-up (average 444.7 days between exams), and 6 had two follow-up MRAs (average 489.5 days between exams). On the first follow-up, 19 (86.4 %) plaques had persistent hyperintense signal in the region of IPH. The second follow-up showed persistent signal in 5/6 plaques (88.3 %). Combined volume of IPH from right and left carotid arteries did not significantly decrease on the first follow-up exam (p = 0.08). CONCLUSIONS: IPH usually retains hyperintense signal on follow-up MRAs, possibly representing recurrent hemorrhage or degraded blood products.

Carotid Artery Tortuosity and Internal Carotid Artery Plaque Composition.

BACKGROUND: Little is known about the association between carotid artery tortuosity and internal carotid artery atherosclerosis. This study sought to evaluate the associations between various types of arterial tortuosity and vulnerable plaque components on magnetic resonance angiography (MRA). MATERIAL AND METHODS: A retrospective review was completed of 102 patients who had undergone MRA neck imaging, with intraplaque hemorrhage (IPH) present in one or both cervical internal carotid arteries (ICA). Each ICA was assessed for two categories of tortuosity: variant arterial pathway(s) (retrojugular and/or retropharyngeal) and abnormal curvature (kinks, loops, and/or coils). All ICA plaques were assessed for the presence or absence of intraplaque hemorrhage (IPH), lipid-rich necrotic core (LRNC), ulceration, and enhancement, as well as the volume of IPH and degree of luminal stenosis. RESULTS: The mean age of included patients was 73.5 years (SD = 9.0 years) and 88 (86.3%) subjects were male. The left carotid plaque was significantly more likely to have IPH (68.6% vs. 47.1%; p = 0.02). The left ICA was more likely to have a retrojugular course (22% vs. 9.9%; p = 0.002) and any variant arterial course (26.5% versus 14.67%, p = 0.01). On the right there was an association between the presence of a LRNC and retropharyngeal and/or retrojugular arterial pathway (p = 0.03). On the left there was an association between the presence of any abnormal arterial curvature and IPH volume (p = 0.03). Neither association met the adjusted statistical threshold after Bonferroni correction, with alpha set at 0.0028. CONCLUSION: ICA tortuosity is not associated with carotid artery plaque composition, and likely does not play a role in the development of high-risk plaques.

Automated CT angiography collateral scoring in anterior large vessel occlusion stroke: A multireader study.

BACKGROUND: Computed tomography (CT) angiography collateral score (CTA-CS) is an important clinical outcome predictor following mechanical thrombectomy for ischemic stroke with large vessel occlusion (LVO). The present multireader study aimed to evaluate the performance of e-CTA software for automated assistance in CTA-CS scoring. MATERIALS AND METHODS: Brain CTA images of 56 patients with anterior LVO were retrospectively processed. Twelve readers of various clinical training, including junior neuroradiologists, senior neuroradiologists, and neurologists graded collateral flow using visual CTA-CS scale in two sessions separated by a washout period. Reference standard was the consensus of three expert readers. Duration of reading time, inter-rater reliability, and statistical comparison of readers' performance metrics were analyzed between the e-CTA assisted and unassisted sessions. RESULTS: e-CTA assistance resulted in significant increase in mean accuracy (58.6% to 67.5%, p = 0.003), mean F1 score (0.574 to 0.676, p = 0.002), mean precision (58.8% to 68%, p = 0.007), and mean recall (58.7% to 69.9%, p = 0.002), especially with slight filling deficit (CTA-CS 2 and 3). Mean reading time was reduced across all readers (103.4 to 59.7 s, p = 0.001), and inter-rater agreement in CTA-CS assessment was increased (Krippendorff's alpha 0.366 to 0.676). Optimized occlusion laterality detection was also noted with mean accuracy (92.9% to 96.8%, p = 0.009). CONCLUSION: Automated assistance for CTA-CS using e-CTA software provided helpful decision support for readers in terms of improving scoring accuracy and reading efficiency for physicians with a range of experience and training backgrounds and leading to significant improvements in inter-rater agreement.

Impact of e-ASPECTS software on the performance of physicians compared to a consensus ground truth: a multi-reader, multi-case study.

Background: The Alberta Stroke Program Early CT Score (ASPECTS) is used to quantify the extent of injury to the brain following acute ischemic stroke (AIS) and to inform treatment decisions. The e-ASPECTS software uses artificial intelligence methods to automatically process non-contrast CT (NCCT) brain scans from patients with AIS affecting the middle cerebral artery (MCA) territory and generate an ASPECTS. This study aimed to evaluate the impact of e-ASPECTS (Brainomix, Oxford, UK) on the performance of US physicians compared to a consensus ground truth. Methods: The study used a multi-reader, multi-case design. A total of 10 US board-certified physicians (neurologists and neuroradiologists) scored 54 NCCT brain scans of patients with AIS affecting the MCA territory. Each reader scored each scan on two occasions: once with and once without reference to the e-ASPECTS software, in random order. Agreement with a reference standard (expert consensus read with reference to follow-up imaging) was evaluated with and without software support. Results: A comparison of the area under the curve (AUC) for each reader showed a significant improvement from 0.81 to 0.83 (p = 0.028) with the support of the e-ASPECTS tool. The agreement of reader ASPECTS scoring with the reference standard was improved with e-ASPECTS compared to unassisted reading of scans: Cohen's kappa improved from 0.60 to 0.65, and the case-based weighted Kappa improved from 0.70 to 0.81. Conclusion: Decision support with the e-ASPECTS software significantly improves the accuracy of ASPECTS scoring, even by expert US neurologists and neuroradiologists.

Acute Ischemic Stroke Presentation Masked by Falsely Localizing Motor Seizure: A Clinical Case Series.

In this case series, we describe a novel observation in which 4 patients with acute ischemic stroke secondary to large vessel occlusion and no history of seizure present with focal seizure activity localizable to a chronic, contralateral infarct. The explanation for this phenomenon is unknown but may be due to a combination of effects involving disrupted interhemispheric inhibitory connections and epileptogenic changes involving chronically infarcted tissue.

Bilateral carotid webs.

Carotid web is thought to be a focal intimal variant of fibromuscular dysplasia, which comprises a high risk of stroke because of blood stasis and subsequent coagulative reactions that occur distal to the web. These lesions generally involve the posterolateral wall of the carotid and their developmental pathogenesis is controversial. This case report describes a 51-year-old woman who presented to the hospital with sudden onset aphasia, right hemi-sensory loss, and right visual field cut. Magnetic resonance imaging (MRI) of the brain demonstrated a left middle cerebral artery (MCA) distribution embolic ischemic infarct with shelf-like linear filling defects in the carotid bulb bilaterally on a computed tomography angiography (CTA) of the head and neck consistent with bilateral carotid webs that were confirmed by catheter angiography. The carotid webs were projecting on the left posteriorly and on the right anteriorly into the inferior aspects of the bilateral proximal internal carotid arteries. The patient was started on clopidogrel and a high-intensity statin and remained on Plavix monotherapy for a 10-month follow up without a recurrent ischemic event.