Search

StarVIBE is a 3D gradient-echo sequence with a radial, stack-of-stars acquisition having spatial resolution and tissue contrast. With newer sequences, it is important to be familiar with sequence tissue contrasts and appearance of anatomical variants. We evaluated 450 patients utilizing this sequence; 35 patients demonstrated fluffy “cotton wool” enhancement at the internal auditory canal fundus without clear pathology. We favor this represents anatomic neurovascular enhancement that StarVIBE is sensitive to and is a touch-me-not finding.

Introduction: Cerebellar hemispheres are commonly used as global references for internal normalization in hemodynamic analysis, including cerebrovascular reactivity (CVR) experiments. We have reported blood oxygen level-dependent (BOLD) MRI coupled acetazolamide for CVR; however, the influence of crossed cerebellar diaschisis (CCD) is understudied in this setting. Importantly, poor signal-to-noise traditionally limits BOLD-CVR to estimation of arbitrary exam conclusions (CVR end ). We developed a custom computational pipeline for dynamic CVR analysis, permitting unprecedented, dynamic maximal CVR (CVR max ) estimates. We describe CCD in a population of patients with chronic unilateral steno-occlusive disease (uSOD) using CVR max . Methods: 32 acetazolamide-challenge BOLD MRI exams in 23 patients with uSOD were examined using a custom denoising and preprocessing strategy for CVR time-signal analysis. BOLD pre and BOLD post were defined as the average of the respective first and last one-minute BOLD data. CVR end was calculated as %CVR=100*( BOLD post – BOLD pre )/ BOLD pre . CVR max was the maximal, denoised per-voxel value. CVR end and CVR max maps were produced. Cerebellar hemispheres ipsilateral and contralateral to the diseased cerebral hemisphere were visually compared for CCD. Pearson correlations were calculated to study CVR max and CVR end in cerebral and cerebellar hemispheres. Results: CCD could be observed in CVR end and CVR max maps (Figure 1). Significant correlations were observed between healthy cerebral and contralateral cerebellar hemispheres (r=0.5992, p=0.0011 for CVR max , r=0.5034, p=0.0054 for CVR end ). CVR max (r=0.4114, p=0.0215) but not CVR end (r=-0.085, p=0.6611) showed correlations between diseased cerebral and contralateral cerebellar hemispheres. Conclusion: We present novel CVR max estimation from dynamic BOLD-MRI, revealing CCD otherwise unrecognized by conventional BOLD-CVR.

Introduction: Prompt detection of intracranial hemorrhage (ICH) on a non-contrast head CT (NCCT) is critical to initial patient triage. Several ICH detection and notification programs now exist, but none presently generate locations or segmentations of suspected ICH, and false-positive notifications are not easily identified. We investigated an enhanced ICH detection tool with heightened immunity to false-positive diagnosis. Methods: NCCT scans from 3 large databases were evaluated for the presence of an ICH (IPH, IVH, SAH or SDH) of >0.4 ml by the automated RAPID ICH 3.0 software module and compared to a consensus detection from 3 neuroradiology experts. Scans were excluded for (1) severe CT acquisition artifacts, (2) prior neurosurgical procedures or (3) intravenous contrast administration. ICH detection accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and positive and negative likelihood ratios by RAPID ICH 3 were determined. Results: A total of 790 studies were included. RAPID ICH 3.0 correctly identified 399/411 ICH-positive cases and 378/379 ICH-negative cases, resulting in a sensitivity of 98.08% and specificity 99.74%, positive predictive value 99.75%, and negative predictive value 96.92% for ICH detection. The positive and negative likelihood ratios for ICH detection were similarly favorable at 367.93 and 0.03 respectively. Mean processing time was Conclusions: In this large data set of nearly 800 patients, the RAPID ICH 3.0 automated software maintained a high sensitivity for detection of ICH, while essentially eliminating false positive identifications, leading to very high positive predictive value.

OBJECTIVE Perfusion imaging identifies anterior circulation stroke patients who respond favorably to endovascular thrombectomy (ET), but its role in basilar artery occlusion (BAO) is unknown. We hypothesized that BAO patients with limited regions of severe hypoperfusion (time to reach maximum concentration in seconds [Tmax] > 10) would have a favorable response to ET compared to patients with more extensive regions involved. METHODS We performed a multicenter retrospective cohort study of BAO patients with perfusion imaging prior to ET. We prespecified a Critical Area Perfusion Score (CAPS; 0-6 points), which quantified severe hypoperfusion (Tmax > 10) in cerebellum (1 point/hemisphere), pons (2 points), and midbrain and/or thalamus (2 points). Patients were dichotomized into favorable (CAPS ≤ 3) and unfavorable (CAPS > 3) groups. The primary outcome was a favorable functional outcome 90 days after ET (modified Rankin Scale = 0-3). RESULTS One hundred three patients were included. CAPS ≤ 3 patients (87%) had a lower median National Institutes of Health Stroke Scale score (NIHSS; 12.5, interquartile range [IQR] = 7-22) compared to CAPS > 3 patients (13%; 23, IQR = 19-36; p = 0.01). Reperfusion was achieved in 84% of all patients, with no difference between CAPS groups (p = 0.42). Sixty-four percent of reperfused CAPS ≤ 3 patients had a favorable outcome compared to 8% of nonreperfused CAPS ≤ 3 patients (odds ratio [OR] = 21.0, 95% confidence interval [CI] = 2.6-170; p 3 patients had a favorable outcome, regardless of reperfusion. In a multivariate regression analysis, CAPS ≤ 3 was a robust independent predictor of favorable outcome after adjustment for reperfusion, age, and pre-ET NIHSS (OR = 39.25, 95% CI = 1.34->999, p = 0.04). INTERPRETATION BAO patients with limited regions of severe hypoperfusion had a favorable response to reperfusion following ET. However, patients with more extensive regions of hypoperfusion in critical brain regions did not benefit from endovascular reperfusion. ANN NEUROL 2021.

To assess whether MR fingerprinting (MRF)–based relaxation properties exhibit cross-sectional and prospective correlations with patient outcome and compare the results with those from DTI. Clinical imaging, MRF, and DTI were acquired in patients (24 ± 10 days after injury (timepoint 1) and 90 ± 17 days after injury (timepoint 2)) and once in controls. Patient outcome was assessed with global functioning, symptom profile, and neuropsychological testing. ADC and fractional anisotropy (FA) from DTI and T1 and T2 from MRF were compared in 12 gray and white matter regions with Mann–Whitney tests. Bivariate associations between MR measures and outcome were assessed using the Spearman correlation and logistic regression. Data from 22 patients (38 ± 12 years; 17 women) and 18 controls (32 ± 8 years; 12 women) were analyzed. Fourteen patients (37 ± 12 years; 11 women) returned for timepoint 2, while two patients provided only timepoint 2 clinical outcome data. At timepoint 1, there were no differences between patients and controls in T1, T2, and ADC, while FA was lower in mTBI frontal white matter. T1 at timepoint 1 and the change in T1 exhibited more (n = 18) moderate to strong correlations (|r|= 0.6–0.85) with clinical outcome at timepoint 2 than T2 (n = 3), FA (n = 7), and ADC (n = 2). High T1 at timepoint 1, and serially increasing T1, accounted for five of the six MR measures with the highest utility for identification of non-recovered patients at timepoint 2 (AUC > 0.80). T1 derived from MRF was found to have higher utility than T2, FA, and ADC for predicting 3-month outcome after mTBI. • In a region-of-interest approach, FA, ADC, and T1 and T2 all showed limited utility in differentiating patients from controls at an average of 24 and 90 days post-mild traumatic brain injury. • T1 at 24 days, and the serial change in T1, revealed more and stronger predictive correlations with clinical outcome at 90 days than did T2, ADC, or FA. • T1 showed better prospective identification of non-recovered patients at 90 days than ADC, T2, and FA.

Background and Purpose: In patients with acute large vessel occlusion, the natural history of penumbral tissue based on perfusion time-to-maximum (T max ) delay is not well established in relation to late-window endovascular thrombectomy. In this study, we sought to evaluate penumbra consumption rates for T max delays in patients with large vessel occlusion evaluated between 6 and 16 hours from last known normal. Methods: This is a post hoc analysis of the DEFUSE 3 trial (The Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke), which included patients with an acute ischemic stroke due to anterior circulation occlusion within 6 to 16 hours of last known normal. The primary outcome is percentage penumbra consumption, defined as (24-hour magnetic resonance imaging infarct volume–baseline core infarct volume)/(T max 6 or 10 s volume–baseline core volume). We stratified the cohort into 4 categories based on treatment modality and Thrombolysis in Cerebral Infarction (TICI score; untreated, TICI 0-2a, TICI 2b, and TICI3) and calculated penumbral consumption rates in each category. Results: We included 141 patients, among whom 68 were untreated. In the untreated versus TICI 3 patients, a median (interquartile range) of 53.7% (21.2%–87.7%) versus 5.3% (1.1%–14.6%) of penumbral tissue was consumed based on T max >6 s ( P max >10 s, we saw a difference of 165.4% (interquartile range, 56.1%–479.8%) versus 25.7% (interquartile range, 3.2%–72.1%; P max >6 s ( P =0.52) or T max >10 s ( P =0.92). Conclusions: Among extended window endovascular thrombectomy patients, T max >10-s mismatch volume may comprise large volumes of salvageable tissue, whereas nearly half the T max >6-s mismatch volume may remain viable in untreated patients at 24 hours.

Background Identification of large vessel occlusion (LVO) is critical to the management of acute ischemic stroke and prerequisite to endovascular therapy in recent trials. Increasing volumes and data complexity compel the development of fast, reliable, and automated tools for LVO detection to facilitate acute imaging triage. Purpose To investigate the performance of an anterior circulation LVO detection platform in a large mixed sample of individuals with and without LVO at cerebrovascular CT angiography (CTA). Materials and Methods In this retrospective analysis, CTA data from recent cerebrovascular trials (CRISP [

Background Ecchordosis physaliphora (EP) is a congenital, uniformly asymptomatic, hamartomatous lesion of the primitive notochord. Herein we report, to our knowledge, the first credible case report of unprovoked intrasphenoidal rupture resulting in recurrent pneumocephalus and cerebrospinal fluid leak, definitively captured over serial imaging during clinical and radiologic surveillance. Case Description A 68-year old woman with Marfan syndrome presented to the emergency department with the worst headache of her life. Imaging demonstrated extensive pneumocephalus and revealed a small, dorsal midline clival lesion consistent with EP and a transsphenoidal defect. Remote imaging encounters confirmed typical EP without pneumocephalus or cortical defect, and an uneventful clinical course years preceding presentation. Over the ensuing months during neurosurgical follow-up, the patient reported recurrent headaches, imbalance, and unprovoked clear rhinorrhea. Further imaging demonstrated an apparently enlarging transsphenoidal defect which was managed by endoscopic transnasal resection and nasoseptal flap. Pathologic evaluation confirmed the diagnosis of EP and chronic dural defect. Conclusions This represents, to our knowledge, the first unambiguous example of spontaneous EP rupture and recurrent pneumocephalus captured over serial imaging. The case further underscores rare but potentially significant complications of EP and highlights management options.

Background The glial–lymphatic pathway is a fluid-clearance pathway consisting of a para-arterial route for the flow of cerebrospinal fluid along perivascular spaces and subsequently toward the brain interstitium. In this case series, we aim to investigate an empirical demonstration of glymphatic clearance of extravasated iodine following perforation incurred during endovascular therapy on serial computed tomography. Methods Six consecutive cases of endovascular perforation during thrombectomy performed between 2005 and 2018 were retrospectively collected by searching our internal database of total 446 thrombectomies. Two cases were excluded because care was withdrawn shortly following the procedure and no follow-up imaging was available. One case was excluded because a ventricular drain was placed. Three cases were hence included in this analysis. Results All 3 cases demonstrated progressive absorption of contrast by the brain parenchyma with eventual contrast disappearance. Conclusions We described a likely in vivo computed tomography correlate of the glymphatic system in a cohort of patients who sustained intraprocedural extravasation during thrombectomy for acute ischemic stroke.

Introduction: Acute ischemic stroke due to basilar artery occlusion (AIS-BAO) results in significant morbidity and mortality. Endovascular thrombectomy (ET) has not been shown to improve outcomes in AIS-BAO patients in randomized trials, which may be due to insufficient selection before ET. We determined whether the Critical Area Perfusion Score (CAPS) and posterior circulation ASPECTS (PC-ASPECTS) predict a favorable response to ET. Methods: We performed a multicenter retrospective study of AIS-BAO patients with perfusion imaging prior to ET. PC-ASPECTS was determined on NCCT by evaluating the cerebellum (1 point/hemisphere), pons (2 points), midbrain (2 points), thalamus (1 point/hemisphere), and posterior cerebral artery (1 point/hemisphere) territories, and points were subtracted for hypodensity in these regions. CAPS was quantified severe hypoperfusion (Tmax >10s) in cerebellum (1 point/hemisphere), pons (2 points), midbrain and/or thalamus (2 points). The primary outcome was a favorable outcome 90-days after ET (modified Rankin Scale [mRS] 0-3). Results: 89 patients were included. CAPS (AUC=0.70 [95% CI: 0.59-0.80]; p=0.002) and PC-ASPECTS (AUC=0.63 [95% CI: 0.52-0.75]; p=0.034) both predicted favorable outcomes in a receiver operating curve analysis, but there was no difference between the two (p=0.434). After dichotomization, patients with favorable CAPS (≤3) and PC-ASPECTS (≥7) were more likely to achieve a good functional outcome after successful reperfusion after ET (Figure). However, an unfavorable CAPS (>3) was associated with poor outcomes despite successful thrombectomy in all patients, whereas 22% of patients with unfavorable PC-ASPECTS ( Conclusions: CAPS and PC-ASPECTS both identify AIS-BAO patients who are likely to have a favorable clinical response to ET. CAPS, but not PC-ASPECTS, appears to accurately identify a subgroup in whom ET may be futile.

Objectives: Hemorrhagic conversion of ischemic stroke (HCIS) is a common complication of cerebral ischemia and is associated with worse stroke outcomes. Differentiation between HCIS and other causes of intracerebral hemorrhage (ICH) can be challenging in practice. We sought to determine whether imaging features of hematoma expansion (HE) can be used to discriminate HCIS from other etiologies of ICH. Materials and Methods: We performed a retrospective review of patients admitted to two large urban hospitals between 2015-2020 with non-traumatic ICH and at least two head CTs within the initial 24 hours and brain MRI prior to discharge to assist with etiology identification. ICH etiology was determined by expert consensus. HE was defined as ≥6 mL and/or ≥33% growth between the first and second scan. Clinical and imaging covariates were studied using univariable and multivariable regression to assess the relationship between cause of intracerebral hemorrhage and HE. We evaluated whether HE was associated with functional status on discharge. Results: 258 patients (median age 66 [51-76], 43% female) met our inclusion criteria including 37 (14%) with HCIS as the presumed cause of hemorrhage. Etiology for ICH was hypertensive in 29%, vascular in 27%, and cerebral amyloid angiopathy in 13%. HE occurred in 11/37 (30%) patients with HCIS, and in 33/221(15%) patients with other causes (p= 0.04). History of anticoagulation use was more frequent in patients with HCIS (24% vs 11%, p= 0.04), although there was no significant difference in admission INR or platelet count. There was no difference in age, admission systolic blood pressure, admission hematoma size or ICH score between groups. HCIS was significantly associated with HE (OR 2.4, CI 1.08-5.34, p=0.03) on univariable analysis. When controlling for hematoma size and anticoagulant use, the relationship between HCIS and HE remained significant (aOR 2.68, CI 1.17-6.13, p=0.02). Patients with HCIS had a higher modified Rankin scale on discharge when compared to those with ICH due to other causes ((mRS 5 [4-5.5] vs. mRS 4 [2-4], p Conclusion: HE within the first 24 hours is more common in HCIS than in other etiologies of ICH. Imaging signatures of HE may be contributory towards determining ICH etiology.

BackgroundHigh-resolution vessel wall MRI (VWI) is increasingly used to characterize intramural disorders of the intracranial vasculature unseen by conventional arteriography.ObjectiveTo evaluate the use of VWI for surveillance of flow diverter (FD) treated aneurysms.Materials and methodsRetrospective study of 28 aneurysms (in 21 patients) treated with a FD (mean 57 years; 14 female). All examinations included VWI and a contemporaneously obtained digital subtraction angiogram. Multiplanar pre- and post-gadolinium 3D, variable flip-angle T1 black-blood VWI was obtained using delay alternating nutation for tailored excitation (DANTE) at 3T. 3D time-of-flight MR angiography (MRA) was also carried out. Images were assessed for in-stent stenosis, aneurysm occlusion, presence and pattern/distribution of aneurysmal or parent vessel gadolinium enhancement.ResultsThe VWI-MRI was performed on average at 361±259 days after the intervention. Follow-up DSA was performed at 338±254 days postintervention. Good or excellent black-blood angiographic quality was recorded in 22/28 (79%) pre-contrast and 21/28 (75%) post-contrast VWI, with no cases excluded for image quality. Aneurysm enhancement was noted in 24/28 (85.7%) aneurysms, including in 79% of angiographically occluded aneurysms and 100% of angiographically non-occluded aneurysms. Enhancement of the stented parent-vessel wall occurred significantly more often when aneurysm enhancement was present (92% vs 33%, p=0.049).ConclusionAdvanced VWI produces excellent depiction of FD-treated aneurysms, with robust evaluation of the parent vessel and aneurysm wall to an extent not achievable with conventional MRI/MRA. Gadolinium enhancement may, however, continue even after enduring catheter angiographic occlusion, confounding interpretation, and requiring cognizance of this potentially prolonged effect in such patients.

We read with great interest the recent study by Copelan et al[1][1] in which the authors concluded that recent administration (< 8 hours) of iodinated contrast renders infarct estimations inaccurate using a commercial CTP processing software. We believe that the conclusions suffer from unassessed

The association between race and ethnicity and microvascular disease in patients with intracerebral hemorrhage (ICH) is unclear. We hypothesized that social determinants of health (SDOHs) mediate the relationship between race and ethnicity and severity of white matter hyperintensities (WMHs) and microbleeds in patients with ICH.We performed a retrospective observational cohort study of patients with ICH at two tertiary care hospitals between 2013 and 2020 who underwent magnetic resonance imaging of the brain. Magnetic resonance imaging scans were evaluated for the presence of microbleeds and WMH severity (defined by the Fazekas scale; moderate to severe WMH defined as Fazekas scores 3-6). We assessed for associations between sex, race and ethnicity, employment status, median household income, education level, insurance status, and imaging biomarkers of microvascular disease. A mediation analysis was used to investigate the influence of SDOHs on the associations between race and imaging features. We assessed the relationship of all variables with discharge outcomes.We identified 233 patients (mean age 62 [SD 16]; 48% female) with ICH. Of these, 19% were Black non-Hispanic, 32% had a high school education or less, 21% required an interpreter, 11% were unemployed, and 6% were uninsured. Moderate to severe WMH, identified in 114 (50%) patients, was associated with age, Black non-Hispanic race and ethnicity, highest level of education, insurance status, and history of hypertension, hyperlipidemia, or diabetes (p 0.05). In the mediation analysis, the proportion of the association between Black non-Hispanic race and ethnicity and the Fazekas score that was mediated by highest level of education was 65%. Microbleeds, present in 130 (57%) patients, was associated with age, highest level of education, and history of diabetes or hypertension (p 0.05). Age, highest level of education, insurance status, and employment status were associated with discharge modified Rankin Scale scores of 3-6, but race and ethnicity was not.The association between Black non-Hispanic race and ethnicity and moderate to severe WMH lost significance after we adjusted for highest level of education, suggesting that SDOHs may mediate the association between race and ethnicity and microvascular disease.

Although less common than in adults, stroke is the sixth leading cause of death in children, affecting ~2–13 children per 100,000 under 18 years of age. Because it is underappreciated clinically, the diagnosis of pediatric stroke is often delayed or even missed, or misdiagnosed as more common conditions such as migraine, epilepsy, or viral illnesses. Since pediatric stroke is caused by unique etiologies and can present differently than in adults, diagnostic imaging should be tailored to the specific and diverse causative entities and distinctive needs of the pediatric population. This chapter provides a comprehensive review of pediatric stroke, including the etiologies, diagnosis, and management, emphasizing the role of neuroimaging in diagnostic and treatment pathways. Understanding the distinct clinical entity of pediatric stroke and the role of imaging in diagnosis is important for early detection and treatment of this underappreciated disease.

Approximately one-quarter of childhood strokes occur in the perinatal period, which includes both fetuses and neonates, affecting between one in 2300–5000 births and representing the primary cause of cerebral palsy. Although the pathogenesis is incompletely understood, risk factors for perinatal stroke are often unique from strokes at other ages, with a combination of maternal, obstetric, anatomic, and genetic factors or predispositions leading to infarct. Clinical presentations of perinatal stroke differ from strokes in older children and adults, often presenting as encephalopathy, seizure, altered mental status, or neurologic deficits. However, neuroimaging remains equally indispensable for diagnosis and prognostication. Here, we provide a comprehensive review of perinatal strokes occurring in fetal and neonatal periods, and discuss the etiologies, diagnosis, management, and prognosis, with a focus on neuroimaging utilization and findings. Understanding the appropriate use of imaging in the distinct clinical entity of perinatal stroke is important for guiding appropriate clinical management.

Background and Aims: Despite significant improvements in survival, severe stroke remains a major cause of mortality. Acute stroke settings have a key role at the end of people’s lives following a severe stroke. Ensuring appropriate, timely, high quality, person-centred, safe and effective end-of-life care in these settings is a professional priority. This study aimed to illuminate bereaved family members’ experiences of end-of-life care in an acute stroke setting following implementation of an end-of-life care training intervention. Methods: A qualitative exploratory study using in-depth, semi-structured, face to face, digitally recorded interviews was conducted. Nine bereaved (> three months) family members, all women, participated. Interviews were fully transcribed and analysed using thematic analysis. Results: The analysis identified three major themes: the variable nature and quality of interaction with healthcare staff; doing care at the end of life and toward the realisation of a certain manner of good death. Findings illuminated some positive end-of-life care practices following a severe stroke in terms of recognising dying and family members’ support, care and engagement in decision-making. However, a pressing need for improved, timely, proactive and regular interaction with family members of people dying imminently in the acute stroke care setting was identified. Conclusions: End-of-life stroke care in the busy, noisy, fast paced acute hospital environments is not without challenge for many reasons. Furthermore, interacting with the family members of imminently dying people is delicate, difficult territory. Yet these are places where people die and the manner of a person’s dying casts an indelible mark on those who live on.

OBJECTIVES: To assess whether MR fingerprinting (MRF)–based relaxation properties exhibit cross-sectional and prospective correlations with patient outcome and compare the results with those from DTI. METHODS: Clinical imaging, MRF, and DTI were acquired in patients (24 ± 10 days after injury (timepoint 1) and 90 ± 17 days after injury (timepoint 2)) and once in controls. Patient outcome was assessed with global functioning, symptom profile, and neuropsychological testing. ADC and fractional anisotropy (FA) from DTI and T(1) and T(2) from MRF were compared in 12 gray and white matter regions with Mann–Whitney tests. Bivariate associations between MR measures and outcome were assessed using the Spearman correlation and logistic regression. RESULTS: Data from 22 patients (38 ± 12 years; 17 women) and 18 controls (32 ± 8 years; 12 women) were analyzed. Fourteen patients (37 ± 12 years; 11 women) returned for timepoint 2, while two patients provided only timepoint 2 clinical outcome data. At timepoint 1, there were no differences between patients and controls in T(1), T(2), and ADC, while FA was lower in mTBI frontal white matter. T(1) at timepoint 1 and the change in T(1) exhibited more (n = 18) moderate to strong correlations (|r|= 0.6–0.85) with clinical outcome at timepoint 2 than T(2) (n = 3), FA (n = 7), and ADC (n = 2). High T(1) at timepoint 1, and serially increasing T(1), accounted for five of the six MR measures with the highest utility for identification of non-recovered patients at timepoint 2 (AUC > 0.80). CONCLUSION: T(1) derived from MRF was found to have higher utility than T(2), FA, and ADC for predicting 3-month outcome after mTBI.

The pathological cascade of tissue damage in mild traumatic brain injury is set forth by a perturbation in ionic homeostasis. However, whether this class of injury can be detected in vivo and serve as a surrogate marker of clinical outcome is unknown. We employ sodium MRI to test the hypotheses that regional and global total sodium concentrations: (i) are higher in patients than in controls and (ii) correlate with clinical presentation and neuropsychological function. Given the novelty of sodium imaging in traumatic brain injury, effect sizes from (i), and correlation types and strength from (ii), were compared to those obtained using standard diffusion imaging metrics. Twenty-seven patients (20 female, age 35.9 ± 12.2 years) within 2 months after injury and 19 controls were scanned with proton and sodium MRI at 3 Tesla. Total sodium concentration, fractional anisotropy and apparent diffusion coefficient were obtained with voxel averaging across 12 grey and white matter regions. Linear regression was used to obtain global grey and white matter total sodium concentrations. Patient outcome was assessed with global functioning, symptom profiles and neuropsychological function assessments. In the regional analysis, there were no statistically significant differences between patients and controls in apparent diffusion coefficient, while differences in sodium concentration and fractional anisotropy were found only in single regions. However, for each of the 12 regions, sodium concentration effect sizes were uni-directional, due to lower mean sodium concentration in patients compared to controls. Consequently, linear regression analysis found statistically significant lower global grey and white matter sodium concentrations in patients compared to controls. The strongest correlation with outcome was between global grey matter sodium concentration and the composite z-score from the neuropsychological testing. In conclusion, both sodium concentration and diffusion showed poor utility in differentiating patients from controls, and weak correlations with clinical presentation, when using a region-based approach. In contrast, sodium linear regression, capitalizing on partial volume correction and high sensitivity to global changes, revealed high effect sizes and associations with patient outcome. This suggests that well-recognized sodium imbalances in traumatic brain injury are (i) detectable non-invasively; (ii) non-focal; (iii) occur even when the antecedent injury is clinically mild. Finally, in contrast to our principle hypothesis, patients’ sodium concentrations were lower than controls, indicating that the biological effect of traumatic brain injury on the sodium homeostasis may differ from that in other neurological disorders. Note: This figure has been annotated., Gerhalter et al. report the in vivo detection of ionic imbalances in mild traumatic brain injury in the form of decreased total sodium concentrations in global grey and white matter compared to controls. These changes correlated with the degree of neuropsychological impairment and differentiated non-recovered patients from controls., Graphical Abstract Graphical Abstract

Introduction: While the thrombotic complications of COVID-19 have been described, there are limited data on its implications in hemorrhagic stroke. The clinical characteristics, underlying stroke mechanism, and outcomes in this group of patients are especially salient as empiric therapeutic anticoagulation becomes increasingly common in the treatment and prevention of thrombotic complications of COVID-19. Methods: We conducted a retrospective cohort study of patients with hemorrhagic stroke (both non-traumatic intracerebral hemorrhage and spontaneous non-aneurysmal subarachnoid hemorrhage) who were hospitalized between 3/1/20-5/15/20 at a NYC hospital system, during the coronavirus pandemic. We compared the demographic and clinical characteristics of patients with hemorrhagic stroke and COVID-19 to those without COVID-19 admitted to our hospital between 3/1/20-5/15/20 (contemporary controls) and 3/1/19-5/15/19 (historical controls), using Fischer’s exact test and non-parametric testing. We adjusted for multiple comparisons using the Bonferroni method. Results: During the study period, 19 out of 4071 (0.5%) patients who were hospitalized with COVID-19 had hemorrhagic stroke on imaging. Of all COVID-19 with hemorrhagic stroke, only 3 had non-aneurysmal SAH without intraparenchymal hemorrhage. Among hemorrhagic stroke and COVID-19 patients, coagulopathy was the most common etiology (73.7%); empiric anticoagulation was started in 89.5% vs 4.2% of contemporary and 10.0% of historical controls (both with p = Conclusion: We observed an overall low rate of imaging-confirmed hemorrhagic stroke among patients hospitalized with COVID-19. Most hemorrhages in COVID-19 patients occurred in the setting of therapeutic anticoagulation and were associated with increased mortality. Further studies are needed to evaluate the safety and efficacy of therapeutic anticoagulation in COVID-19 patients.

Introduction: We sought to evaluate the accuracy of perfusion-weighted imaging (PWI) in late presenting patients for estimating the infarct volume at 24 hours after presentation. Methods: This is a secondary analysis of DEFUSE 3, which included stroke patients with anterior circulation occlusion within 6-16 hours of last known normal. The primary outcome is the final infarct volume on a 24-hour MRI scan (volume of DWI positive tissue), adjusted for the baseline infarct volume. We censored 3 patients with 24-hour follow-up MRI infarct volumes >300 mL, which we considered non-physiologic for a hemispheric stroke. The primary predictors are the baseline volume of Tmax >6s, Tmax >10s, and hypoperfusion intensity ratio (HIR: Tmax10/Tmax6) on CT/MR perfusion at hospital admission. We stratified the cohort into 4 categories (untreated, TICI 0-2a, TICI 2b, and TICI3) and fit linear regression models to each of our predictors. Results: We included 147 patients, of which 69 were untreated, 17 had TICI 0-2a, 46 had TICI 2b, and 15 had TICI 3. In untreated patients, both HIR and Tmax10 volume were predictive of adjusted 24-hour follow-up infarct volume (Table). In treated patients, there were no consistent relationships between the perfusion imaging variables and adjusted final infarct volume (Table). Conclusion: For patients with late window anterior circulation large vessel occlusion stroke, HIR and Tmax10 volume appear to be reliable predictors of subsequent infarct volume in untreated patients. For patients treated with thrombectomy, further research is warranted to better understand the more complex relationship between baseline perfusion imaging and the 24 hour, and beyond, infarct volume.

Background: Identification of large vessel occlusion (LVO) is paramount in the urgent evaluation of acute ischemic stroke (AIS). Emergent interpretation of large and high-complexity data sets, however, may impose strains upon imaging and clinical workflows, motivating development of fast and accurate computer-aided approaches to facilitate LVO detection in the emergency setting. This study investigates the performance of a fully automated LVO detection platform in a mixed cohort of stroke subjects with and without LVO on head and neck CT angiography (CTA). Methods: CTA from two cerebrovascular trials were enriched with cases from eleven global sites. Imaging and clinical variables were balanced between populations including in LVO positivity and across demographic and imaging environments to the extent achievable. Independent and fully blinded review for intracranial ICA or MCA M1 LVO was performed by two subspecialty neuroradiologists. A novel, user-independent imaging analysis application ( RAPID-LVO , iSchemaview inc) was used to predict LVO presence, location, and overall performance relative to reader consensus. Any discordance between readers was adjudicated by a blinded tertiary reader with subspecialty training. Sensitivity, specificity, and receiver-operating characteristics were determined by an independent statistician. Performance thresholds were set a priori, including a lower bound of the 95% CI of sensitivity and specificity of ≥0.8 at mean times-to-notification Results: 217 CTA (median age 65.5, 53% male, 109 LVO(+)) were included. Lower confidence limits of sensitivity and specificity exceeded 90% (sensitivity 0.963, 95% CI 0.909-0.986; specificity 0.981, 95% CI 0.935-0.995), surpassing pre-specified performance benchmarks. Subgroup analyses revealed no decrement in performance relative to subject age or sex, vendor systems, or location of the examination within or outside the United States. The area under the receiver operating characteristics curve was 0.99 (95% CI: 0.971-0.999) and average time-to-notification was 3.18 minutes. Conclusion: RAPID-LVO offers fast, highly accurate, and fully user-independent large vessel occlusion detection across all tested clinical and imaging environments.

Introduction: In patients with acute large vessel occlusion, the definition of penumbral tissue based on T max delay perfusion imaging is not well established in relation to late-window endovascular thrombectomy (EVT). In this study, we sought to evaluate penumbra consumption rates for T max delays in patients treated between 6 and 16 hours from last known normal. Methods: This is a secondary analysis of the DEFUSE-3 trial, which included patients with an acute ischemic stroke due to anterior circulation occlusion within 6-16 hours of last known normal. The primary outcome is percentage penumbra consumption defined as (24 hour infarct volume-core infarct volume)/(Tmax volume-baseline core volume). We stratified the cohort into 4 categories (untreated, TICI 0-2a, TICI 2b, and TICI3) and calculated penumbral consumption rates. Results: We included 143 patients, of which 66 were untreated, 16 had TICI 0-2a, 46 had TICI 2b, and 15 had TICI 3. In untreated patients, a median (IQR) of 48% (21% - 85%) of penumbral tissue was consumed based on Tmax6 as opposed to 160.6% (51% - 455.2%) of penumbral tissue based on Tmax10. On the contrary, in patients achieving TICI 3 reperfusion, a median (IQR) of 5.3% (1.1% - 14.6%) of penumbral tissue was consumed based on Tmax6 and 25.7% (3.2% - 72.1%) of penumbral tissue based on Tmax10. Conclusion: Contrary to prior studies, we show that at least 75% of penumbral tissue with Tmax > 10 sec delay can be salvaged with successful reperfusion and new generation devices. In untreated patients, since infarct expansion can occur beyond 24 hours, future studies with delayed brain imaging are needed to determine the optimal T max delay threshold that defines penumbral tissue in patients with proximal anterior circulation large vessel occlusion.

BackgroundAge and infarct volume are among the most powerful predictors of outcome after large vessel occlusion acute strokes (LVOS).ObjectiveTo study the impact of age-adjusted final infarct volume (FIV) on functional outcomes.MethodsReview of a prospectively collected thrombectomy database at a tertiary care center between September 2010 and February 2018. Consecutive patients with anterior circulation LVOS who achieved full reperfusion (modified Thrombolysis in Cerebral Infarction 3) were categorized into four age groups: (G1) Results516 patients were analyzed (G1: n=171, G2: n=130, G3: n=103, G4: n=112). Patients with poor outcome had a larger FIV in each group (pIn multivariate analysis, adjusting for confounders including age and FIV, achieving a FIV less than the age-adjusted threshold was an independent predictor of good outcome (aOR=2.72, 95% CI 1.41 to 5.24, pConclusionsAge-adjusted infarct volume represents a strong outcome discriminator beyond age and infarct volume in isolation and might help to refine patient selection and improve outcome prognostication in stroke thrombectomy.

Background and Purpose While the thrombotic complications of COVID-19 have been well described, there are limited data on clinically significant bleeding complications including hemorrhagic stroke. The clinical characteristics, underlying stroke mechanism, and outcomes in this particular subset of patients are especially salient as therapeutic anticoagulation becomes increasingly common in the treatment and prevention of thrombotic complications of COVID-19. Methods We conducted a retrospective cohort study of patients with hemorrhagic stroke (both non-traumatic intracerebral hemorrhage and spontaneous non-aneurysmal subarachnoid hemorrhage) who were hospitalized between March 1, 2020, and May 15, 2020, within a major healthcare system in New York, during the coronavirus pandemic. Patients with hemorrhagic stroke on admission and who developed hemorrhage during hospitalization were both included. We compared the clinical characteristics of patients with hemorrhagic stroke and COVID-19 to those without COVID-19 admitted to our hospital system between March 1, 2020, and May 15, 2020 (contemporary controls), and March 1, 2019, and May 15, 2019 (historical controls). Demographic variables and clinical characteristics between the individual groups were compared using Fischer’s exact test for categorical variables and nonparametric test for continuous variables. We adjusted for multiple comparisons using the Bonferroni method. Results During the study period in 2020, out of 4071 patients who were hospitalized with COVID-19, we identified 19 (0.5%) with hemorrhagic stroke. Of all COVID-19 with hemorrhagic stroke, only three had isolated non-aneurysmal SAH with no associated intraparenchymal hemorrhage. Among hemorrhagic stroke in patients with COVID-19, coagulopathy was the most common etiology (73.7%); empiric anticoagulation was started in 89.5% of these patients versus 4.2% in contemporary controls (p ≤ .001) and 10.0% in historical controls (p ≤ .001). Compared to contemporary and historical controls, patients with COVID-19 had higher initial NIHSS scores, INR, PTT, and fibrinogen levels. Patients with COVID-19 also had higher rates of in-hospital mortality (84.6% vs. 4.6%, p ≤ 0.001). Sensitivity analyses excluding patients with strictly subarachnoid hemorrhage yielded similar results. Conclusion We observed an overall low rate of imaging-confirmed hemorrhagic stroke among patients hospitalized with COVID-19. Most hemorrhages in patients with COVID-19 infection occurred in the setting of therapeutic anticoagulation and were associated with increased mortality. Further studies are needed to evaluate the safety and efficacy of therapeutic anticoagulation in patients with COVID-19.

BACKGROUND AND PURPOSE: Intracranial hemorrhage (ICH) is an important event that is diagnosed on head NCCT. Increased NCCT utilization in busy hospitals may limit timely identification of ICH. RAPID ICH is an automated hybrid 2D–3D convolutional neural network application designed to detect ICH that may allow for expedited ICH diagnosis. We determined the accuracy of RAPID ICH for ICH detection and ICH volumetric quantification on NCCT. MATERIALS AND METHODS: NCCT scans were evaluated for ICH by RAPID ICH. Consensus detection of ICH by 3 neuroradiology experts was used as the criterion standard for RAPID ICH comparison. ICH volume was also automatically determined by RAPID ICH in patients with intraparenchymal or intraventricular hemorrhage and compared with manually segmented ICH volumes by a single neuroradiology expert. ICH detection accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and positive and negative likelihood ratios by RAPID ICH were determined. RESULTS: We included 308 studies. RAPID ICH correctly identified 151/158 ICH cases and 143/150 ICH-negative cases, which resulted in high sensitivity (0.956, CI: 0.911–0.978), specificity (0.953, CI: 0.907–0.977), positive predictive value (0.956, CI: 0.911-0.978), and negative predictive value (0.953, CI: 0.907–0.977) for ICH detection. The positive likelihood ratio (20.479, CI 9.928–42.245) and negative likelihood ratio (0.046, CI 0.023–0.096) for ICH detection were similarly favorable. RAPID ICH volumetric quantification for intraparenchymal and intraventricular hemorrhages strongly correlated with expert manual segmentation (correlation coefficient r = 0.983); the median absolute error was 3 mL. CONCLUSIONS: RAPID ICH is highly accurate in the detection of ICH and in the volumetric quantification of intraparenchymal and intraventricular hemorrhages.

Background and Purpose: With the spread of coronavirus disease 2019 (COVID-19) during the current worldwide pandemic, there is mounting evidence that patients affected by the illness may develop clinically significant coagulopathy with thromboembolic complications including ischemic stroke. However, there is limited data on the clinical characteristics, stroke mechanism, and outcomes of patients who have a stroke and COVID-19. Methods: We conducted a retrospective cohort study of consecutive patients with ischemic stroke who were hospitalized between March 15, 2020, and April 19, 2020, within a major health system in New York, the current global epicenter of the pandemic. We compared the clinical characteristics of stroke patients with a concurrent diagnosis of COVID-19 to stroke patients without COVID-19 (contemporary controls). In addition, we compared patients to a historical cohort of patients with ischemic stroke discharged from our hospital system between March 15, 2019, and April 15, 2019 (historical controls). Results: During the study period in 2020, out of 3556 hospitalized patients with diagnosis of COVID-19 infection, 32 patients (0.9%) had imaging proven ischemic stroke. Cryptogenic stroke was more common in patients with COVID-19 (65.6%) as compared to contemporary controls (30.4%, P =0.003) and historical controls (25.0%, P Conclusions: We observed a low rate of imaging-confirmed ischemic stroke in hospitalized patients with COVID-19. Most strokes were cryptogenic, possibly related to an acquired hypercoagulability, and mortality was increased. Studies are needed to determine the utility of therapeutic anticoagulation for stroke and other thrombotic event prevention in patients with COVID-19.

Despite the severity of coronavirus disease 2019 (COVID-19) being more frequently related to acute respiratory distress syndrome and acute cardiac and renal injuries, thromboembolic events have been increasingly reported. We report a unique series of young patients with COVID-19 presenting with cerebral venous system thrombosis. Three patients younger than 41 years of age with confirmed Severe Acute Respiratory Syndrome coronavirus 2 (SARS-Cov-2) infection had neurologic findings related to cerebral venous thrombosis. They were admitted during the short period of 10 days between March and April 2020 and were managed in an academic institution in a large city. One patient had thrombosis in both the superficial and deep systems; another had involvement of the straight sinus, vein of Galen, and internal cerebral veins; and a third patient had thrombosis of the deep medullary veins. Two patients presented with hemorrhagic venous infarcts. The median time from COVID-19 symptoms to a thrombotic event was 7 days (range, 2-7 days). One patient was diagnosed with new-onset diabetic ketoacidosis, and another one used oral contraceptive pills. Two patients were managed with both hydroxychloroquine and azithromycin; one was treated with lopinavir-ritonavir. All patients had a fatal outcome. Severe and potentially fatal deep cerebral thrombosis may complicate the initial clinical presentation of COVID-19. We urge awareness of this atypical manifestation.

BACKGROUND AND PURPOSE Mechanical thrombectomy (MT) has helped many patients achieve functional independence. The effect of time-to-treatment based in specific epochs and as related to Alberta Stroke Program Early CT Score (ASPECTS) has not been established. The goal of the study was to evaluate the association between last known normal (LKN)-to-puncture time and good functional outcome. METHODS We conducted a retrospective cohort study of prospectively collected acute ischemic stroke patients undergoing MT for large vessel occlusion. We used binary logistic regression models adjusted for age, Modified Treatment in Cerebral Ischemia score, initial National Institutes of Health Stroke Scale, and noncontrast CT ASPECTS to assess the association between LKN-to-puncture time and favorable outcome defined as Modified Rankin Score 0-2 on discharge. RESULTS Among 421 patients, 328 were included in analysis. Increased LKN-to-puncture time was associated with decreased probability of good functional outcome (adjusted odds ratio [aOR] ratio per 15-minute delay = .98; 95% confidence interval [CI], .97-.99; P = .001). This was especially true when LKN-puncture time was 0-6 hours (aOR per 15-minute delay = .94; 95% CI, .89-.99; P = .05) or ASPECTS 8-10 (aOR = .98; 95% CI, .97-.99; P = .002) as opposed to when LKN-puncture time was 6-24 hours (aOR per 15-minute delay = .99; 95% CI, .97-1.00; P = .16) and ASPECTS

Introduction: The insular cortex controls several aspects of vital function including autonomic regulation, and strokes affecting the insula have been associated with dysautonomia, cardiac dysfunction, and arrhythmias. Previous studies have shown an association between insular strokes, elevated troponin levels, and atrial fibrillation (AF). In this study, we aim to determine the association between cardiac biomarkers and insular involvement of the infarct and hypothesize that insular involvement implicates a cardioembolic source. Methods: We abstracted data from a prospective comprehensive stroke center registry of consecutive patients with a discharge diagnosis of acute ischemic stroke who underwent brain imaging (CT or MRI) and work up to determine stroke mechanism. Data included demographics, clinical baseline variables, laboratory tests (including admission troponin level), and transthoracic echocardiographic variables (regional wall motion abnormalities, ejection fraction, and left atrial volume index), and stroke subtype. Multivariable logistic regression models were built to determine associations between AF, and cardiac biomarkers and insular infarcts. Results: We identified 1224 patients who met the inclusion criteria; 397 (32.4%) had insular involvement of the infarct. In multivariable models, insular infarcts were associated with AF (adjusted OR 1.73, 95% CI 1.23-2.43, p = 0.001) and left atrial volume index (adjusted OR per standard deviation increase 1.30, 95% CI 1.13-1.49, p = 0.001). There was a trend for association between insular involvement and positive troponin level (adjusted OR 1.45 95% CI 0.91-2.33, p = 0.122) but not with regional wall motion abnormalities (adjusted OR 1.13, 95% CI 0.69-1.84, p = 0.627). Insular involvement was associated with cardioembolic stroke subtype (45.8% vs. 26.7%, p Conclusion: The insular cortex is commonly involved in patients with atrial fibrillation and/or atrial dilation and maybe a neuroimaging biomarker of cardioembolic stroke. Larger studies are needed to confirm this association and test anticoagulation therapy in patients with insular infarcts.

Background and Purpose: There is limited data on predictors of 30-day stroke or death in patients with symptomatic intracranial atherosclerosis (sICAS) undergoing stenting. We aim to determine these predictors. Methods: This is a post-hoc analysis SAMMPRIS including patients who underwent angioplasty/stenting. We determined associations between patient-specific, lesion-specific, and procedure-specific variables, and FDA-approved indications and the primary outcome (stroke or death at 30 days) using logistic regression analyses. Results: We identified 213 patients; 30 patients (14.1%) met the primary outcome. The odds of stroke or death was higher with non-smokers vs. smokers (adjusted OR 4.46, 95% CI 1.79-11.1) and increasing lesion length in millimeters (adjusted OR 1.20, 95% CI 1.02-1.39). These had modest predictive value: absence of smoking history (sensitivity=66.7% and specificity=65.4%) and lesion length (Area Under Curve=0.606). Furthermore, event rates were not significantly different between patients with and without the FDA approved indication for stenting (15.9% vs. 12%, p = 0.437). Conclusion: In SAMMPRIS patients who underwent angioplasty/stenting, neither clinical and neuroimaging variables nor the FDA indication for stenting reliably predicted the primary outcome. Further work in identifying reliable biomarkers of stroke/death in patients with sICAS is needed before considering new clinical trials of stenting.

Introduction: Previous studies have shown an elevated risk of MI (MI) in patients with symptomatic intracranial atherosclerotic disease (sICAD), but the mediators of increased risk of MI or death in these patients remain uncertain. We aim to determine risk factors associated with MI or death in patients with symptomatic ICAD. Methods: Patients enrolled in SAMMPRIS had sICAD and were randomized to aggressive medical management (AMM) vs. stenting and AMM. The primary outcome of this post-hoc analysis is MI or vascular death within 2 years of follow-up. We excluded patients who were lost to follow up, had a stroke during follow up, had non-vascular death or death within 30 days of stenting. Patients meeting the inclusion criteria were divided into two groups: those with vs. those without the primary outcome. We used binary logistic regression to determine predictors of incident MI or death within 2 years. Results: Of the 451 patients enrolled in SAMMPRIS, 350 patients met the inclusion criteria (reasons for exclusion: 4 deaths occurring within 30 days of stenting, 63 with ischemic stroke, 6 with symptomatic hemorrhage, 7 patients with non-cardiovascular death within 2 years, and 21 lost to follow up). At 2 years, 17 patients (4.9%) had MI/death; 10 patients had MI and 7 had cardiovascular deaths. In a multivariable model, factors associated with MI/death were: history of coronary artery disease (adjusted OR 3.19, 95% CI 1.14 - 8.93, p = 0.027) and systolic blood pressure (adjusted OR per 10 mm increase 1.20, 95% CI 0.98 - 1.44, p = 0.080). This risk was abut 24% with both predictors present and 2.8% with them absent (Figure). Conclusion: Higher systolic blood pressure and pre-existing cardiovascular disease were independently associated with incident MI or vascular death in patients with sICAD, despite medical management. Further studies are needed to confirm this association and test interventions to reduce this risk.

BACKGROUND Oxygen extraction fraction (OEF) elevation predicts increased ischemic stroke incidence among patients with carotid steno-occlusive disease, and can be estimated from quantitative susceptibility mapping (QSM) MRI. PURPOSE To explore QSM oximetry during acetazolamide (ACZ) challenge, hypothesizing that detectable OEF alterations will reflect hemodynamic compromise in unilateral cerebrovascular disease (CVD) patients. STUDY TYPE Retrospective. SUBJECTS Fourteen unilateral CVD patients, and 24 healthy controls (HC). FIELD STRENGTH/SEQUENCE Multiecho gradient echo (GRE) and T1 -weighted images at 3T. ASSESSMENT We constructed QSM images and R2* maps from multiecho GRE images. QSM-OEF maps were generated from the susceptibility difference between venous blood and background brain tissue. Intrasubject diseased/contralateral hemisphere OEF ratios in the middle cerebral artery (MCA) territories were calculated. Intravascular susceptibility in the straight sinus (SS) and MCA was also measured. STATISTICAL TESTS The result significance was determined using t-tests and Pearson's correlation. RESULTS Mean and standard deviation for the patient diseased/contralateral OEF ratios were 1.15 ± 0.14 at baseline and 1.23 ± 0.17 post-ACZ. Disease group R2* ratios were 0.95 ± 0.05 at baseline and 1.03 ± 0.08 post-ACZ. Left/right OEF and R2* ratios for the HC group were 0.98 ± 0.06 and 0.99 ± 0.038, respectively. Susceptibility (ppb) in the SS and MCA in patients was 162.63 ± 35.4 and -22.33 ± 13.70, respectively, at baseline, 124.56 ± 37.43 and -19.27 ± 23.14 post-ACZ. The HC group SS and MCA susceptibility was 146.10 ± 24.79 and -19.59 ± 12.37, respectively. Patient group OEF ratios were greater than 1.0 before and after ACZ challenge (P < 0.01 and < 0.001, respectively, one-sample t-test), and were greater than HC ratios (P < 0.001 unpaired t-test). OEF and R2* ratios increased from baseline to post-ACZ (P = 0.024, 0.004, respectively, paired t-test). Detectable blood oxygenation change was confirmed by finding SS susceptibility decreased from baseline to post-ACZ (P < 0.001, paired t-test), while MCA susceptibility did not change significantly (P = 0.67, paired t-test). DATA CONCLUSION These results suggest QSM is sensitive to dynamic OEF modulation during hemodynamic augmentation. LEVEL OF EVIDENCE 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2019;50:175-182.

Background The optimal diagnostic evaluation for patients with angiographically negative subarachnoid hemorrhage (AN-SAH) remains controversial. Objective To assess the utilization rate and diagnostic yield of imaging tests routinely obtained in identifying a structural cause for AN-SAH. Methods In this retrospective multicenter study, consecutive adult patients admitted with nontraumatic, AN-SAH between 01/2010 and 12/2015 were included. Patients with intraparenchymal, subdural, or epidural hematomas in addition to SAH were excluded. Outcomes studied included utilization rate, diagnostic yield, and median time from admission for the following imaging tests: initial computed tomography angiography (CTA) and digital subtraction angiography (DSA), brain and cervical spine magnetic resonance imaging (MRI), and any repeat DSA or CTA performed either during initial admission or at long-term follow-up. Results A total of 752 patients were included (mean age, 53 yr; 54% male). Initial CTA and DSA were performed in 89% and 100% of patients, respectively. Brain MRI was performed in 75% of patients and was positive in 0.7% of cases. Cervical spine MRI was performed in 61% of patients and was positive in 0.2% of cases. Repeat, same-admission follow-up DSA and CTA were performed in 48% and 51% of patients and were positive in 3.3% and 1% of cases, respectively. Delayed follow-up DSA and CTA after discharge were performed in 26% and 7% of patients and were positive in 2% and 3.7% of cases, respectively, all with negative prior imaging studies. Conclusion Cervical spine and brain MRI have extremely low diagnostic yield, both are commonly utilized in patients with AN-SAH; while repeat DSA and CTA are utilized less commonly and have slightly higher diagnostic yield.

Background and Purpose The purpose of this study is to evaluate the frequency and clinical utility of repeat cerebrovascular imaging with computed tomography angiography (CTA) of the head after contrast-enhanced magnetic resonance angiography (CE-MRA) of the head in acute stroke patients. Materials and Methods All stroke patients admitted to 2 academic medical centers from January 1, 2012 through December 31, 2014 were identified as part of prospective radiology database if they underwent CE-MRA of the head followed by subsequent CTA of the head within 7 days. Two vascular neurologists blinded to CTA results retrospectively reviewed medical records including documented indications for imaging studies and clinical changes in patients to determine necessity of CTA. Results Of 1355 acute stroke patients who underwent CE-MRA of the head, 195 (14%) patients underwent subsequent CTA of the head within 7 days, including 33 patients with nondiagnostic CE-MRA because of motion artifact. Of the remaining 162 (12%) patients, 69 (43%) were considered to have an unnecessary CTA of the head. Multivariable logistic regression analysis identified (1) absence of new neurologic examination changes [OR 7.29; 95% CI 1.92-27.63] and (2) same documented indication for both studies [OR 6.47; 95% CI 3.04-13.78] as significant predictors of an unnecessary CTA. Changes in clinical management after CTA were significantly more common in necessary CTAs compared with studies determined to be unnecessary (42% versus 7%, P Conclusion The utility of repeat cerebrovascular imaging with CTA of the head following a diagnostic CE-MRA is low when there is no change in neurologic examination or when ordered for the same indication.

Objective To assess the utility of computed tomographic (CT) perfusion for selection of patients for endovascular therapy up to 18 hours after symptom onset. Methods We conducted a multicenter cohort study of consecutive acute stroke patients scheduled to undergo endovascular therapy within 90 minutes after a baseline CT perfusion. Patients were classified as “target mismatch” if they had a small ischemic core and a large penumbra on their baseline CT perfusion. Reperfusion was defined as >50% reduction in critical hypoperfusion between the baseline CT perfusion and the 36-hour follow-up magnetic resonance imaging. Results Of the 201 patients enrolled, 190 patients with an adequate baseline CT perfusion study who underwent angiography were included (mean age = 66 years, median NIH Stroke Scale [NIHSS] = 16, median time from symptom onset to endovascular therapy = 5.2 hours). Rate of reperfusion was 89%. In patients with target mismatch (n = 131), reperfusion was associated with higher odds of favorable clinical response, defined as an improvement of ≥8 points on the NIHSS (83% vs 44%; p = 0.002, adjusted odds ratio [OR] = 6.6, 95% confidence interval [CI] = 2.1–20.9). This association did not differ between patients treated within 6 hours (OR = 6.4, 95% CI = 1.5–27.8) and those treated > 6 hours after symptom onset (OR = 13.7, 95% CI = 1.4–140). Interpretation The robust association between endovascular reperfusion and good outcome among patients with the CT perfusion target mismatch profile treated up to 18 hours after symptom onset supports a randomized trial of endovascular therapy in this patient population. Ann Neurol 2017;81:849–856