Impact on stroke subtype diagnosis of early diffusion-weighted magnetic resonance imaging and magnetic resonance angiography

Deep Learning-Based Automatic Classification of Ischemic Stroke Subtype Using Diffusion-Weighted Images

BACKGROUND AND PURPOSE

Accurate classification of ischemic stroke subtype is important for effective secondary prevention of stroke. We used diffusion-weighted image (DWI) and atrial fibrillation (AF) data to train a deep learning algorithm to classify stroke subtype.

METHODS

Model development was done in 2,988 patients with ischemic stroke from three centers by using U-net for infarct segmentation and EfficientNetV2 for subtype classification. Experienced neurologists (n=5) determined subtypes for external test datasets, while establishing a consensus for clinical trial datasets. Automatically segmented infarcts were fed into the model (DWI-only algorithm). Subsequently, another model was trained, with AF included as a categorical variable (DWI+AF algorithm). These models were tested: (1) internally against the opinion of the labeling experts, (2) against fresh external DWI data, and (3) against clinical trial dataset.

RESULTS

In the training-and-validation datasets, the mean (±standard deviation) age was 68.0±12.5 (61.1% male). In internal testing, compared with the experts, the DWI-only and the DWI+AF algorithms respectively achieved moderate (65.3%) and near-strong (79.1%) agreement. In external testing, both algorithms again showed good agreements (59.3%-60.7% and 73.7%-74.0%, respectively). In the clinical trial dataset, compared with the expert consensus, percentage agreements and Cohen's kappa were respectively 58.1% and 0.34 for the DWI-only vs. 72.9% and 0.57 for the DWI+AF algorithms. The corresponding values between experts were comparable (76.0% and 0.61) to the DWI+AF algorithm.

CONCLUSION

Our model trained on a large dataset of DWI (both with or without AF information) was able to classify ischemic stroke subtypes comparable to a consensus of stroke experts.

Impact of early MRI in ischemic strokes beyond hyper-acute stage to improve patient outcomes, enable early discharge, and realize cost savings

BACKGROUND

Early in-patient MR Imaging may assist in identifying stroke etiology, facilitating prompt secondary prevention for ischemic strokes (IS), and potentially enhancing patient outcomes. This study explores the impact of early in patient MRI on IS patient outcomes and healthcare resource use beyond the hyper-acute stage.

METHODS

In this retrospective registry-based study, 771 admitted transient ischemic attack (TIA) and IS patients at Halifax's QEII Health Centre from 2015 to 2019 underwent in-patient MRI. Cohort was categorized into two groups based on MRI timing: early (within 48 h) and late. Logistic regression and Poisson log-linear models, adjusted for age, sex, stroke severity, acute stroke protocol (ASP) activation, thrombolytic, and thrombectomy, were employed to examine in-hospital, discharge, post-discharge, and healthcare resource utilization outcomes.

RESULTS

Among the cohort, 39.6 % received early in-patient MRI. ASP activation and TIA were associated with a higher likelihood of receiving early MRI. Early MRI was independently associated with a lower rate of symptomatic changes in neurological status during hospitalization (adjusted odds ratio [OR], 0.42; 95 % confidence interval [CI], 0.20-0.88), higher odds of good functional outcomes at discharge (1.55; 1.11-2.16), lower rate of non-home discharge (0.65; 0.46-0.91), shorter length of stay (regression coefficient, 0.93; 95 % CI, 0.89-0.97), and reduced direct cost of hospitalization (0.77; 0.75-0.79).

CONCLUSION

Early in-patient MRI utilization in IS patients post-hyper-acute stage was independently associated with improved patient outcomes and decreased healthcare resource utilization, underscoring the potential benefits of early MRI during in-patient management of IS. Further research, including randomized controlled trials, is warranted to validate these findings.

TOAST stroke subtype classification in clinical practice: implications for the Get With The Guidelines-Stroke nationwide registry

Introduction

The TOAST (Trial of ORG 10172 in Acute Stroke Treatment) is the most commonly used ischemic stroke subtype classification system worldwide and a required field in the US National Get With The Guidelines-Stroke (GWTG-Stroke) registry. However, stroke diagnostics have advanced substantially since the TOAST classification was designed 30 years ago, potentially making it difficult to apply reliably.

Methods

In this prospective diagnostic accuracy study, we analyzed consecutive ischemic stroke patients admitted to a Comprehensive Stroke Center between July-October 2021. Clinical practice TOAST classification diagnoses rendered by the stroke team in the electronic medical record (EMR) at discharge were retrieved from GWTG-Stroke registry and compared to a reference ("gold") standard diagnosis derived from agreement between two expert raters after review of the EMR and patient imaging.

Results

Among 49 patients; age was 72.3 years (±12.1), 53% female, and presenting NIHSS median 3 (IQR 1-11). Work-up included: brain imaging in 100%; cardiac rhythm assessment in 100%; cervical/cerebral vessel imaging in 98%; TTE ± TEE in 92%; and TCD emboli evaluation in 51%. Reference standard diagnoses were: LAA-6%, SVD-14%, CE-39%, OTH-10%, UND-M (more than one cause)-20%, and UND-C (cryptogenic)-10%. GWTG-Stroke TOAST diagnoses agreed with reference standard diagnoses in 30/49 (61%). Among the 6 subtype diagnoses, specificity was generally high (84.8%-97.7%), but sensitivity suboptimal for LAA (33%), OTH (60%), UND-M (10%), and UND-C (20%). Positive predictive value was suboptimal for 5 of the 6 subtypes: LAA (13%), SVD (58%), OTH (75%), UND-M (50%), and UND-C (50%).

Discussion

Clinical practice TOAST classification subtype diagnoses entered into the GWTG-Stroke registry were accurate in only 61% of patients, a performance rate that, if similarly present at other centers, would hamper the ability of the national registry to provide dependable insights into subtype-related care. Development of an updated ischemic stroke subtype classification system, with algorithmic logic embedded in electronic medical records, is desirable.

Stroke classification and treatment support system artificial intelligence for usefulness of stroke diagnosis

Background and aims

It is important to diagnose cerebral infarction at an early stage and select an appropriate treatment method. The number of stroke-trained physicians is unevenly distributed; thus, a shortage of specialists is a major problem in some regions. In this retrospective design study, we tested whether an artificial intelligence (AI) we built using computer-aided detection/diagnosis may help medical physicians to classify stroke for the appropriate treatment.

Methods

To build the Stroke Classification and Treatment Support System AI, the clinical data of 231 hospitalized patients with ischemic stroke from January 2016 to December 2017 were used for training the AI. To verify the diagnostic accuracy, 151 patients who were admitted for stroke between January 2018 and December 2018 were also enrolled.

Results

By utilizing multimodal data, such as DWI and ADC map images, as well as patient examination data, we were able to construct an AI that can explain the analysis results with a small amount of training data. Furthermore, the AI was able to classify with high accuracy (Cohort 1, evaluation data 88.7%; Cohort 2, validation data 86.1%).

Conclusion

In recent years, the treatment options for cerebral infarction have increased in number and complexity, making it even more important to provide appropriate treatment according to the initial diagnosis. This system could be used for initial treatment to automatically diagnose and classify strokes in hospitals where stroke-trained physicians are not available and improve the prognosis of cerebral infarction.

Hypersensitive MR angiography based on interlocking stratagem for diagnosis of cardiac-cerebral vascular diseases

Magnetic resonance (MR) angiography is one of the main diagnostic approaches for cardiac-cerebral vascular diseases. Nevertheless, the non-contrast-enhanced MR angiography suffers from its intrinsic problems derived from the blood flow-dependency, while the clinical Gd-chelating contrast agents are limited by their rapid vascular extravasation. Herein, we report a hypersensitive MR angiography strategy based on interlocking stratagem of zwitterionic Gd-chelate contrast agents (PAA-Gd). The longitudinal molar relaxivity of PAA-Gd was 4.6-times higher than that of individual Gd-chelates as well as appropriate blood half-life (73.8 min) and low immunogenicity, enabling sophisticated micro-vessels angiography with a resolution at the order of hundred micrometers. A series of animal models of cardiac-cerebrovascular diseases have been built for imaging studies on a 7.0 T MRI scanner, while the clinical translation potential of PAA-Gd has been evaluated on swine on a 3.0 T clinical MRI scanner. The current studies offer a promising strategy for precise diagnosis of vascular diseases.

Predictors of congruency between clinical and radiographic Oxfordshire Community Stroke Project Classification subtypes

BACKGROUND

The Oxfordshire Community Stroke Project (OCSP) classification has been widely used to assess ischemic stroke patients based on clinical characteristics alone. However, the correlation between the clinical presentation evaluated using OCSP and imaging findings is yet to be determined. Our study aimed to describe the baseline characteristics of the OCSP subtypes of patients admitted with ischemic stroke and evaluate the predictors of the relationship between clinical and neuroimaging findings.

METHODS

Patients with a confirmed diagnosis of ischemic stroke admitted to a comprehensive stroke center in Brazil between February 2015 and October 2017 were eligible for the study. All participants underwent computed tomography (CT) at admission and follow-up neuroimaging within seven days, per the institutional protocol. Trained staff classified patients according to the OCSP at hospital admission. The radiographic OCSP classification was retrospectively assessed based on the last follow-up neuroimaging by investigators unaware of the clinical classification.

RESULTS

The overall agreement rates ranged from 65.5% to 88.7%. Lower NIHSS scores, absent hyperdense MCA sign, higher ASPECTS, and absent brainstem symptoms were related to a higher risk of misclassification. Treatment with intravenous tPA was associated with reclassification in patients with total anterior circulation syndrome. For predicting radiographic posterior circulation involvement, vertigo (OR 2.9, 95% CI 1.7-5.1, p < 0.001) and brainstem symptoms (OR 35, 95% CI 20.5-60.2, p < 0.001) were directly associated with correct classification, but motor and higher cerebral function were not correlated.

CONCLUSION

The clinical OCSP classification presented good congruency rates with the neuroimaging findings. However, patients with lacunar syndromes are often misclassified when radiological criteria are considered.

Correlation Analysis between Chronic Osteomyelitis and Bacterial Biofilm

Objective

To study the role of bacterial biofilm (BBF) in the formation of chronic osteomyelitis and its prevention and treatment.

Methods

In this paper, a large amount of relevant literature was searched for analysis and summary, and the key words "chronic osteomyelitis," "bacterial biofilm," "infection," and "debridement" were searched in databases, mainly CNKI, Wanfang, and Wipu. The search was conducted until December 2020. The role of bacterial biofilm formation in chronic osteomyelitis and its prevention were analyzed.

Results

Chronic osteomyelitis is formed mainly due to poor blood supply and drug-resistant bacteria, of which cellular biofilm is the most important cause. BBF forms on the surface of necrotic soft tissue and bone tissue, which has a protective effect on bacteria and greatly enhances their resistance to antibiotics, leading to difficulties in complete bacterial clearance and recurrent infections in osteomyelitis.

Conclusion

Through an in-depth study of the molecular biology and signal transduction of osteomyelitis biofilm, antibiotic biofilm treatment strategies and surgical debridement remain the focus of clinical translation of chronic osteomyelitis.

Comparative analysis of functional outcome for CT-based versus MRI-based evaluation in acute ischemic stroke prior to mechanical thrombectomy

Background

This study aims to compare functional outcome for Computed tomography (CT)-based versus Magnetic resonance imaging (MRI)-based evaluation in acute ischemic stroke patients prior to Mechanical thrombectomy (MT) in less than 6-h window period in anterior circulation stroke. Participants were patients admitted from September 2, 2018 to September 2, 2020 with an acute ischemic stroke who underwent mechanical thrombectomy treatment. Total duration of MRI stroke protocol and CT scan with Computed tomography angiography (CTA) was 12 min 57 s, and 9 min 23 s, respectively. Follow-up for periodic Modified Rankin Scale (MRS) was performed at 3 months.

Results

Number of patients included in the study were 152 with mean age of 54.6 (range 22–80) years with male predominance (n = 102). Mean GCS on admission was 12 (4–15) and 13(4–14) in CT and MRI group, respectively. National Institute of Health stroke scale (NIHSS) on admission was 17 (4–30) and 16(4–30) and at discharge was 7 (2–23) and 6(2–22) in CT-based group and MRI-based group, respectively. In the MRI group 65.5% had good outcome with mRS (0–2) at 3-month follow-up compared to 35.51% in CT group.

Conclusion

The current standard neuroimaging in acute ischemic stroke patients is CT and CTA brain. Using MRI over CT scan for acute ischemic stroke may improve clinical outcomes for the subgroup of patients who have an unclear diagnosis and who have higher risk of complications with MT. Even though MRI and MRA take longer period to acquire, patient’s clinical outcome was better in MRI group in comparison to CT group and was comparable to that of the five major endovascular trials.

Left Atrial Volume Index as a Predictor for Large-Vessel Occlusion in Cardiogenic Cerebral Infarction: A Single-Center Cohort Study

OBJECTIVE

The left atrial volume index (LAVI) is considered to be the most accurate index to estimate the size of the left atrium (LA). In this study, we investigated the relationship between LA size measured by LAVI and the occurrence of large-vessel occlusion (LVO) in patients with cardiogenic cerebral infarction (CCI).

METHODS

This retrospective single-center cohort study involved 118 patients with CCI within the internal carotid artery (ICA) or middle cerebral artery regions seen between January 2015 and July 2020. In all patients, the type of CCI was determined according to the Diffusion-Weighted Imaging-Alberta Stroke Program Early Computed Tomography Scores (TOAST) subtype diagnosis criteria. LVO was defined as positive when magnetic resonance imaging and computed tomography angiography showed ICA, M1, or M2 occlusion, with all others defined as non-LVO. Clinical characteristics, including LAVI, were evaluated in the records of several patients to investigate if they were risk factors for developing LVO.

RESULTS

Seventy patients (59%) were diagnosed as having LVO infarction (ICA occlusion, n = 19 [16%]; M1 occlusion, n = 26 [22%]; and M2 occlusion, n = 25 [21%]). Echocardiography showed no difference between LVO and non-LVO in terms of the ejection fraction (P = 0.64), LA dimension (P = 0.93), and LA volume (P = 0.06). However, LAVI significantly differed between the LVO and non-LVO groups (P = 0.02). Multivariate logistic regression analysis showed larger LAVI as a significant risk factor for LVO (P = 0.01).

CONCLUSIONS

Our findings suggest that a larger LAVI is a predictor of developing LVO in patients with CCI.

Newly-identified blood biomarkers of neurological damage are correlated with infarct volume in patients with acute ischemic stroke

Our group recently performed a genome-wide informatic analysis that highlighted eight brain-enriched proteins with strong potential to serve as blood biomarkers of neurological injury (GFAP, MBP, β-synuclein, OPALIN, MT-3, SNAP-25, KIF5A, MOBP), including six that have yet to be widely investigated. In this study, our aim was to determine whether the circulating levels of these proteins could be used to approximate the extent of neural tissue damage in ischemic stroke. To address this aim, blood was collected from 43 ischemic stroke patients immediately upon hospital admission. The serum levels of the eight candidate proteins were measured via ELISA, infarct volume was assessed via manual tracing of neuroradiological images, and correlational analysis was performed to examine potential associative relationships. The serum levels of all eight proteins exhibited positive correlations with infarct volume, however the strongest associations were observed in a subset of four proteins known to originate from neurons specifically (MT-3, SNAP-25, KIF5A, β-synuclein). Combining the serum levels of these neuron-originating proteins using principal components analysis produced a single composite value that was more strongly correlated with infarct volume than the levels of any single protein considered in isolation (r = 0.48, p < 0.001). Measures of these proteins could potentially be used to provide a minimally invasive approximation of lesion size when advanced imaging techniques are not available, or when imaging results are inconclusive.

Early MRI Versus CT Scan for Evaluation of Cerebrovascular Events in a Community Hospital: A Cost Minimization Analysis

Background: Diffusion-weighted MRI is shown to be equally effective, as a CT scan, in diagnosing ischemic and hemorrhagic strokes. Would it be cost-effective to perform an early MRI instead of a CT head?

Methods: A retrospective chart review was conducted between October 1, 2015, through October 1, 2017, for patients admitted for possible cerebrovascular accident (CVA). Inclusion criteria were age >/= 18 years and symptoms suggestive of a stroke. Exclusion criteria were pregnancy and age <18 years. We obtained information regarding patients' length of hospital stay, imaging modalities performed, and the related cost. We performed a cost analysis by calculating the total duration and cost of hospitalization, and cost for each investigation.

Results: The study included 828 patients who underwent CT head without contrast initially. A total of 634 (76.5%) patients got MRI brain without contrast, 261 (31.5%) had MRI brain with and without contrast, 406 (49%) had magnetic resonance angiography (MRA) head without contrast, 60 patients (7.2%) had MRA neck without contrast, 272 (32.8%) had MRA neck with and without contrast, and 1 patient (0.1%) had MRA head with and without contrast. The hospital duration for all patients was 1,797 days. The average duration per patient was 1.9364 days. The total health care cost for all patients was $25,383,983. Average per patient hospitalization cost was $25,383,983/828 = $30656.98. Average per day cost for all patients would be $25383983/1.93days = $13,152,322.8. Combined costs of all MRIs performed on all patients = $1,413,014. If MRI brain with and without contrast was considered as an initial modality, a total of $335,340 can be saved on the diagnostic imaging. Ultimately, it can also help reduce the hospitalization duration.

Conclusion: Early MRI (in appropriately selected patients) can reduce the length of hospitalization and cut some health care costs. However, more studies are required to develop appropriate patient selection criteria.

Association Between Low-Dose Rivaroxaban With or Without Aspirin and Ischemic Stroke Subtypes: A Secondary Analysis of the COMPASS Trial

Importance

The COMPASS (Cardiovascular Outcomes for People Using Anticoagulation Strategies) randomized clinical trial was stopped early owing to the efficacy of low-dose rivaroxaban plus aspirin in preventing major cardiovascular events. The main reason for early trial termination was the effect of combination therapy on reducing ischemic strokes.

Objective

To analyze the association between low-dose rivaroxaban with or without aspirin and different ischemic stroke subtypes.

Design, Setting, and Participants

This is a secondary analysis of a multicenter, double-blind, randomized, placebo-controlled study that was performed in 33 countries from March 12, 2013, to May 10, 2016. Patients with stable atherosclerotic vascular disease were eligible, and a total of 27 395 participants were randomized and followed up to February 6, 2017. All first ischemic strokes and uncertain strokes that occurred by this date were adjudicated using TOAST (Trial of Org 10172 in Acute Stroke Treatment) criteria. The analysis of ischemic stroke subtypes was evaluated using an intention-to-treat principle. Statistical analysis was performed from March 12, 2013, to February 6, 2017.

Interventions

Participants received rivaroxaban (2.5 mg twice a day) plus aspirin (100 mg once a day), rivaroxaban (5 mg twice a day), or aspirin (100 mg once a day).

Main Outcomes and Measures

Risk of ischemic stroke subtypes during follow-up.

Results

A total of 291 patients (66 women; mean [SD] age, 69.4 [8.5] years; 43 [14.8%] had a previous nonlacunar stroke) experienced an ischemic stroke. During the study, 49 patients (16.8%) received a diagnosis of atrial fibrillation. Applying TOAST criteria, 59 strokes (20.3%) were cardioembolic, 54 strokes (18.6%) were secondary to greater than 50% stenosis of the ipsilateral internal carotid artery, 42 strokes (14.4%) had a negative evaluation that met criteria for embolic stroke of undetermined source, and 21 strokes (7.2%) were secondary to small vessel disease. There were significantly fewer cardioembolic strokes (hazard ratio [HR], 0.40 [95% CI, 0.20-0.78]; P = .005) and embolic strokes of undetermined source (HR, 0.30 [95% CI, 0.12-0.74]; P = .006) in the combination therapy group compared with the aspirin-only group. A trend for reduction in strokes secondary to small vessel disease (HR, 0.36 [95% CI, 0.12-1.14]; P = .07) was not statistically significant. No significant difference was observed between the 2 groups in strokes secondary to greater than 50% carotid artery stenosis (HR, 0.85 [95% CI, 0.45-1.60]; P = .61). Rivaroxaban, 5 mg, twice daily showed a trend for reducing cardioembolic strokes compared with aspirin (HR, 0.57 [95% CI, 0.31-1.03]; P = .06) but was not associated with reducing other stroke subtypes.

Conclusions and Relevance

For patients with systemic atherosclerosis, low-dose rivaroxaban plus aspirin was associated with large, significant reductions in cardioembolic strokes and embolic strokes of undetermined source. However, these results of exploratory analysis need to be independently confirmed before influencing clinical practice.

Trial Registration

ClinicalTrials.gov identifier: NCT01776424.

Blood-Based Biomarkers Are Associated with Different Ischemic Stroke Mechanisms and Enable Rapid Classification between Cardioembolic and Atherosclerosis Etiologies

Stroke is a top leading cause of death, which occurs due to interference in the blood flow of the brain. Ischemic stroke (blockage) accounts for most cases (87%) and is further subtyped into cardioembolic, atherosclerosis, lacunar, other causes, and cryptogenic strokes. The main value of subtyping ischemic stroke patients is for a better therapeutic decision-making process. The current classification methods are complex and time-consuming (hours to days). Specific blood-based biomarker measurements have promising potential to improve ischemic stroke mechanism classification. Over the past decades, the hypothesis that different blood-based biomarkers are associated with different ischemic stroke mechanisms is increasingly investigated. This review presents the recent studies that investigated blood-based biomarker characteristics differentiation between ischemic stroke mechanisms. Different blood-based biomarkers are specifically discussed (b-type natriuretic peptide, d-dimer, c-reactive protein, tumor necrosis factor-α, interleukin-6, interleukin-1β, neutrophil-lymphocyte ratio, total cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein and apolipoprotein A), as well as the different cut-off values that may be useful in specific classifications for cardioembolic and atherosclerosis etiologies. Lastly, the structure of a point-of-care biosensor device is presented, as a measuring tool on-site. The information presented in this review will hopefully contribute to the major efforts to improve the care for stroke patients.

B-Type Natriuretic Peptide as a Significant Brain Biomarker for Stroke Triaging Using a Bedside Point-of-Care Monitoring Biosensor

Stroke is a widespread condition that causes 7 million deaths globally. Survivors suffer from a range of disabilities that affect their everyday life. It is a complex condition and there is a need to monitor the different signals that are associated with it. Stroke patients need to be rapidly diagnosed in the emergency department in order to allow the admission of the time-limited treatment of tissue plasminogen activator (tPA). Stroke diagnostics show the use of sophisticated technologies; however, they still contain limitations. The hidden information and technological advancements behind the utilization of biomarkers for stroke triaging are significant. Stroke biomarkers can revolutionize the way stroke patients are diagnosed, monitored, and how they recover. Different biomarkers indicate different cascades and exhibit unique expression patterns which are connected to certain pathologies in the human body. Over the past decades, B-type natriuretic peptide (BNP) and its derivative N-terminal fragment (NT-proBNP) have been increasingly investigated and highlighted as significant cardiovascular biomarkers. This work reviews the recent studies that have reported on the usefulness of BNP and NT-proBNP for stroke triaging. Their classification association is also presented, with increased mortality in stroke, correlation with cardioembolic stroke, and an indication of a second stroke recurrence. Moreover, recent scientific efforts conducted for the technological advancement of a bedside point-of-care (POC) device for BNP and NT-proBNP measurements are discussed. The conclusions presented in this review may hopefully assist in the major efforts that are currently being conducted in order to improve the care of stroke patients.

Neurobiology of Recovery of Motor Function after Stroke: The Central Nervous System Biomarker Effects of Constraint-Induced Movement Therapy

Recovery of motor function after stroke involves many biomarkers. This review attempts to identify the biomarker effects responsible for recovery of motor function following the use of Constraint-Induced Movement Therapy (CIMT) and discuss their implications for research and practice. From the studies reviewed, the biomarker effects identified include improved perfusion of motor areas and brain glucose metabolism; increased expression of proteins, namely, Brain-Derived Neurotrophic Factor (BDNF), Vascular Endothelial Growth Factor (VEGF), and Growth-Associated Protein 43 (GAP-43); and decreased level of Gamma-Aminobutyric Acid (GABA). Others include increased cortical activation, increased motor map size, and decreased interhemispheric inhibition of the ipsilesional hemisphere by the contralesional hemisphere. Interestingly, the biomarker effects correlated well with improved motor function. However, some of the biomarker effects have not yet been investigated in humans, and they require that CIMT starts early on poststroke. In addition, one study seems to suggest the combined use of CIMT with other rehabilitation techniques such as Transcortical Direct Stimulation (tDCs) in patients with chronic stroke to achieve the biomarker effects. Unfortunately, there are few studies in humans that implemented CIMT during early poststroke. Thus, it is important that more studies in humans are carried out to determine the biomarker effects of CIMT especially early on poststroke, when there is a greater opportunity for recovery. Furthermore, it should be noted that these effects are mainly in ischaemic stroke.

Diagnosis of ischemic stroke using circulating levels of brain-specific proteins measured via high-sensitivity digital ELISA

Limited lower detection ranges associated with traditional immunoassay techniques have prevented the use of brain-specific proteins as blood biomarkers of stroke in the acute phase of care, as these proteins are often only present in circulation at low concentrations. Digital ELISA is a newly developed technique with allows for quantification of proteins in biofluids with up to 1000 times greater sensitivity than conventional ELISA techniques. The purpose of this study was to determine whether the extended lower limits of detection associated with digital ELISA could enable the use of brain-specific proteins as blood biomarkers of ischemic stroke during triage. Blood was sampled from ischemic stroke patients (n = 14) at emergency department admission, as well as from neurologically normal controls matched in terms of risk factors for cardiovascular disease (n = 33). Plasma levels of two brain-specific axonal proteins, neurofilament light chain (NfL) and tau, were measured via digital ELISA, and receiver-operating characteristic analysis was used to determine their ability to discriminate between groups. Plasma levels of NfL and tau were both significantly elevated in stroke patients versus controls, and could respectively discriminate between groups with 92.9% sensitivity / 84.9% specificity, and 85.7% sensitivity / 54.6% specificity. Furthermore, adjustment of measured NfL and Tau levels according to the lower-limits of detection associated with commercially-available conventional ELISA assays resulted in a dramatic and statistically significant decrease in diagnostic performance. Collectively, our results suggest that the increased analytical sensitivity of digital ELISA could enable the use of brain-specific proteins as blood biomarkers of ischemic stroke during triage.

Ischemic stroke risk during post-discharge phases of heart failure: association of left ventricular concentric geometry

Despite a higher risk of ischemic stroke in hospitalized patients with acute heart failure (HF), little is known about the risk of ischemic stroke during the post-discharge phases of HF. Here we investigated (1) the ischemic stroke incidence rate during the post-discharge phases among HF patients receiving standard treatments; (2) the association between ischemic stroke incidence and clinical background, including cardiac structure and function. Among 950 patients who required hospitalization for HF (median duration: 19 days) at our institution, where they received standard treatments, we investigated stroke occurrences during the 2-year period following their discharge and retrospectively evaluated their clinical data. Relative wall thickness (RWT) and left ventricular (LV) mass were determined based on echocardiographic measurements and then used to determine LV geometric patterns. During the follow-up period, ischemic stroke occurred in 25 patients (2.6%) after hospital discharge (1.4 per 100 patient-years). The incidence rate of IS tended to be higher in patients with AF than those without AF (1.8 vs. 1.0 per 100 patient-years, respectively). Notably, multivariate analysis revealed a significant association between RWT and ischemic stroke risk (p < 0.05). RWT was associated with ischemic stroke risk in patients with AF or left atrial enlargement, but not in patients without them. These findings suggest that even with standard HF treatments, the risk of ischemic stroke is high in patients with HF. Moreover, LV concentric geometry is a significant risk factor for ischemic stroke in patients with HF, especially in those with left atrial remodeling and/or AF.

Diffusion-weighted MRI for outcome prediction in early Legg-Calvé-Perthes disease: Medium-term radiographic correlations

BACKGROUND

Outcome prediction at the early sclerotic stage of Legg-Calvé-Perthes disease (LCPD) is valuable to select patients likely to benefit from early surgery. The metaphyseal apparent diffusion coefficient (ADC) ratio correlated significantly with Herring's classification of LCPD in a preliminary study of 49 MRIs, in which values greater than 1.63 were associated with poor outcomes. The objective of this study was to determine whether the femoral neck ADC ratio, with the 1.63 cut-off, determined at the initial stage of LCPD correlated with medium-term radiographic outcomes.

HYPOTHESIS

The metaphyseal ADC ratio correlates significantly with medium-term radiographic outcomes of LCPD.

MATERIALS AND METHODS

A prospective study was performed in 27 children (mean age, 13 years; range, 9.5-16 years) who underwent 49 MRIs at the sclerosis or fragmentation stage of unilateral LCPD. ADCs measured bilaterally at the femoral head and neck were used to compute the corresponding ADC ratios between the affected and unaffected sides. The patients received regular follow-up for at least 5 years. The correlation between the ADC ratios and Stulberg grade at last follow-up was assessed.

RESULTS

After a mean follow-up of 6.8 years (range, 5.2-8.4 years) from the date of the first MRI, 13 hips were Stulberg 1 or 2, 13 were Stulberg 3 or 4, and 1 was Stulberg 5. The metaphyseal ADC ratio increased significantly with the Stulberg grade (p<0.01). When only MRIs obtained at the early stage of sclerosis were considered, the correlation remained significant (p=0.03). It was also significant in the subgroup of surgically treated patients (p<0.0001) but was not significant in the subgroup without surgery (p=0.51). A metaphyseal ADC ratio greater than 1.63 was associated with a worse Stulberg grade (p=0.02).

DISCUSSION/CONCLUSION

Diffusion-weighted MRI is a non-irradiating and non-invasive investigation that contributes to the management of LCPD when used in combination with morphological MRI sequences. Elevation of the femoral neck ADC is a finding of adverse prognostic significance that correlates with Herring's grade at the fragmentation stage and with Stulberg's grade at the healed stage. Early ADC elevation in the affected femoral neck can serve to select those patients most likely to benefit from early surgery before the fragmentation stage, i.e., before Herring's classification can be applied.

LEVEL OF EVIDENCE

III, prospective uncontrolled study 3.

Lipid Indices, Elastin Turnover and the Development of Microvascular Complications – A Study in Diabetic Patients with Arterial Hypertension

Background and Aims: An important factor in the development of vascular wall lesions is the degradation of the elastic fiber major protein – elastin. Elastin peptides (EDP) derived from this degradation are present in the circulation and are a stimulus for the production of anti-elastin antibodies (AEAbs) IgM, IgG and IgA. The aim of this study was to investigate the possible association between AEAbs, lipid indices and the development of microvascular complications.

Material and Methods: Sera of 93 patients with type 2 diabetes mellitus (T2DM) and arterial hypertension (AH) were investigated (mean age 61,4 ± 11,3 years, diabetes duration 9,88 ± 3,12 years; hypertension duration 9,28 ± 4,98). ELISA was used for determination of anti-elastin antibodies. These levels were compared to serum AEAbs in 42 age- and sex-matched controls. Diabetic patients were divided in two groups according to the presence – Group 1 (n = 67) or absence – Group 2 (n = 26) of microangiopathy. The lipid profile and lipid indices (log TG/HDL, LDL/HDL, TC/HDL and TG/HDL) were also studied.

Results: Patients with T2DM and AH showed statistically significant higher levels of serum AEAbs IgA than healthy controls – 0,338 (0,133÷0,452) vs. 0,006 (0,052÷0,068) (KW = 19,54; P < 0.0001). Group 1 showed statistically significant higher levels of AEAbs IgA than patients without microangiopathy – 0,353 (0,173÷0,471) vs. 0,235 (0,098÷0,377) (KW = 3,36; p = 0.05) and healthy controls – 0,353 (0,173÷0,471) vs. 0,006 (0,052÷0,068) (KW = 20,37; p < 0,0001) (0.37 ± 0,03 vs. 0.06÷0.01) (p = 0.0001). Patients from Group 2 showed significantly higher levels of AEAbs IgA than controls 0,235 (0,098÷0,377) vs. 0,006 (0,052÷0,068) (KW = 8,54; P = 0.003). AEAbs IgA showed correlation with insulin dose (r = −0.35); (p = 0.01), SBP (r = 0.31); (p = 0.001), HbA1c (r = 0.21); (p = 0.04), BMI (r = 0.22); (p = 0.01). AEAbs IgA correlated with log TG/HDL (r = 0.28); (p = 0.001), LDL/HDL (r = 0.22); (p = 0.01) TC/HDL (r = 0.22); (p = 0.01) and with TG/HDL (r = 0.15); (p = 0.05).

Conclusion: Our study proved a relationship between elevation of AEAb IgA, high lipid indices and the development of microvascular complications in patients with type 2 diabetes mellitus and arterial hypertension.

Care of the Critically Ill Pediatric Sickle Cell Patient

Sickle cell disease is the most common inherited disease in the United States. Through the effects of hemolysis and vaso-occlusion, it has the potential to incite critical illness involving multiple organ systems. Children with sickle cell disease are at risk of multiple types of shock resulting in a need for ICU care. Our youngest patients with sickle cell disease are at highest risk of infection due to lack of splenic function, and this can present with septic shock. Hypovolemic shock can occur secondary to severe acute anemia as seen with splenic sequestration or a delayed transfusion reaction. As one ages, the risk of cardiac dysfunction – diastolic and systolic dysfunction as well as pulmonary hypertension – can result in cardiogenic shock. In addition to shock, patients with sickle cell disease are at risk for respiratory failure from acute chest syndrome as well as acute neurologic deterioration from stroke. For these reasons, critical care physicians must be familiar with the unique management of sickle cell complications in order to provide the best possible care for this vulnerable population.

Noncardioembolic Stroke in Patients with Atrial Fibrillation

Atrial fibrillation (AF) could be a coincidental finding in certain patients with ischemic stroke and increased burden of underlying cardiovascular disease. Concomitant large-vessel atheromatosis and cerebral small vessel disease may be the actual cause of stroke, and distinguishing between different pathophysiologic mechanisms could impose substantial diagnostic difficulties. Despite routine use of oral anticoagulants (OACs) in patients with AF based on their risk for embolism (ie, CHA2DS2-Vasc score), antithrombotic agents may exert differential effects depending on stroke etiology and stroke subtyping should be evaluated as an additional component of risk stratification that could facilitate optimal management. In the present study, we summarize the evidence on noncardioembolic (non-CE) stroke and treatment approaches based on different stroke subtypes in patients with AF. In particular, approximately one-third of patients with AF seem to suffer a non-CE stroke. Within this category, 11% to 24% of patients present high-grade carotid stenosis and 9% to 16% of ischemic strokes are classified as lacunar. In terms of secondary prevention, the effectiveness of OACs in preventing non-CE stroke has been disputed. Additional large-scale prospective studies are warranted to assess the pathophysiologic stroke mechanisms in patients with AF and compare the differential efficacy of antithrombotic treatment strategies in non-CE ischemic syndromes.

Comparison of application values of CT and MRI in the diagnosis of early Lacunar Infarction

Objective:

To analyze and compare the values of computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis of early lacunar infarction.

Methods:

Eighty-eight patients with early lacunar infarction who were admitted to the hospital were selected as research subjects, and all of them underwent MRI and CT. The study was conducted at our hospital between May 2015 to July 2016.

Results:

Four hundred and forty-one lesions were detected by MRI, and 145 were detected by CT. Most of the lesions were located at the thalamus, frontal lobe and parietal lobe. The detection rate of small lesions with a diameter less than 5 cm using MRI was significantly higher than that with CT, and the difference had statistical significance (P<0.05). Forty-nine cases who reached hospital within six hours were scanned in which no images were observed by CT, while small flake-like or spotted images were observed in 47 cases by MRI. The efficacy of MRI in displaying early lesions and micro lesions was superior to that of CT.

Conclusion:

In the diagnosis of early lacunar infarction, the detection rate of lesions with MRI is significantly higher than that with CT. MRI can clearly display the specific conditions of lesions, which is worth clinical promotion.

Shifts in Leukocyte Counts Drive the Differential Expression of Transcriptional Stroke Biomarkers in Whole Blood

Our group recently identified a panel of ten genes whose RNA expression levels in whole blood have utility for detection of stroke. The purpose of this study was to determine the mechanisms by which these genes become differentially expressed during stroke pathology. First, we assessed the transcriptional distribution of the ten genes across the peripheral immune system by measuring their expression levels on isolated neutrophils, monocytes, B-lymphocytes, CD-4+ T-lymphocytes, CD-8+ T-lymphocytes, and NK-cells generated from the blood of healthy donors (n = 3). Then, we examined the relationship between the whole-blood expression levels of the ten genes and white blood cell counts in a cohort of acute ischemic stroke patients (n = 36) and acute stroke mimics (n = 15) recruited at emergency department admission. All ten genes displayed strong patterns of lineage-specific expression in our analysis of isolated leukocytes, and their whole-blood expression levels were correlated with white blood cell differential across the total patient population, suggesting that many of them are likely differentially expressed in whole blood during stroke as an artifact of stroke-induced shifts in leukocyte counts. Specifically, factor analysis inferred that over 50% of the collective variance in their whole-blood expression levels across the patient population was driven by underlying variance in white blood cell counts alone. However, the cumulative expression levels of the ten genes displayed a superior ability to discriminate between stroke patients and stroke mimics relative to white blood cell differential, suggesting that additional less prominent factors influence their expression levels which add to their diagnostic utility. These findings not only provide insight regarding this particular panel of ten genes, but also into the results of prior stroke transcriptomics studies performed in whole blood.

A Potential New Risk Factor for Stroke: Streptococcus Mutans With Collagen-Binding Protein

BACKGROUND

Among human oral bacteria, particular kinds of Streptococcus mutans (SM) known as dental caries pathogens contain a collagen-binding protein, Cnm, and show platelet aggregation inhibition and matrix metalloproteinase-9 activation. We have previously reported that these strains may be a risk factor for intracerebral hemorrhage. As a major sample-providing hospital, we report the clinical details, including intracranial aneurysms and ischemic stroke.

METHODS

After the study received approval from the Ethical Committee, 429 samples of whole saliva were obtained from patients who were admitted to or visited our hospital between February 16, 2010, and February 28, 2011. The study cohort comprised 48 patients with cardioembolic stroke (CES), 151 with non-CES infarct, 54 with intracerebral hemorrhage (ICH), 43 with ruptured intracranial aneurysm (RIA), and 97 with unruptured intracranial aneurysm (UIA). Cultured SM was identified as Cnm-positive when the corresponding gene was positive. The results were compared with those from 79 healthy volunteers. Relationships between Cnm-positive SM and known risk factors, including hypertension, diabetes, hyperlipidemia, smoking, and alcohol consumption, were analyzed.

RESULTS

A statistically significant high Cnm-positive rate was observed in patients with CES, non-CES infarct, ICH, and RIA (P = 0.002, 0.039, 0.013, and 0.009, respectively). There were no relationships between Cnm-positive SM and known risk factors.

CONCLUSIONS

Specific types of oral SM can be a risk factor for cardioembolic infarct, intracerebral hemorrhage, and intracranial aneurysm rupture. Further study is needed.

Etiological classification of ischemic stroke in young patients: a comparative study of TOAST, CCS, and ASCO

Analysis of stroke subtypes is important for making treatment decisions and prognostic evaluations. The TOAST classification system is most commonly used, but the CCS and ASCO classification systems might be more useful to identify stroke etiologies in young patients whose strokes have a wide range of different causes. In this manuscript, we aim to compare the differences in subtype classification between TOAST, CCS, and ASCO in young stroke patients. The TOAST, CCS, and ASCO classification schemes were applied to 151 patients with ischemic stroke aged 18-49 years old and the proportion of subtypes classified by each scheme was compared. For comparison, determined etiologies were defined as cases with evident and probable subtypes when using the CCS scheme and cases with grade 1 and 2 subtypes but no other grade 1 subtype when using the ASCO scheme. The McNemar test with Bonferroni correction was used to assess significance. By TOAST, 41.1% of patients' stroke etiology was classified as undetermined etiology, 19.2% as cardioembolic, 13.2% as large artery atherosclerosis, 11.3% as small vessel occlusion, and 15.2% as other causes. Compared with TOAST, both CCS and ASCO assigned fewer patients to the undetermined etiology group (30.5% p < 0.001 and 26.5% p < 0.001, respectively) and assigned more patients to the small vessel occlusion category (19.9%, p < 0.001, and 21.9%, p < 0.001, respectively). Additionally, both schemes assigned more patients to the large artery atherosclerosis group (15.9 and 16.6%, respectively). The proportion of patients assigned to either the cardioembolic or the other causes etiology did not differ significantly between the three schemes. Application of the CCS and ASCO classification schemes in young stroke patients seems feasible, and using both schemes may result in fewer patients being classified as undetermined etiology. New studies with more patients and a prospective design are needed to explore this topic further.

Point-of-Care-Testing in Acute Stroke Management: An Unmet Need Ripe for Technological Harvest

Stroke, the second highest leading cause of death, is caused by an abrupt interruption of blood to the brain. Supply of blood needs to be promptly restored to salvage brain tissues from irreversible neuronal death. Existing assessment of stroke patients is based largely on detailed clinical evaluation that is complemented by neuroimaging methods. However, emerging data point to the potential use of blood-derived biomarkers in aiding clinical decision-making especially in the diagnosis of ischemic stroke, triaging patients for acute reperfusion therapies, and in informing stroke mechanisms and prognosis. The demand for newer techniques to deliver individualized information on-site for incorporation into a time-sensitive work-flow has become greater. In this review, we examine the roles of a portable and easy to use point-of-care-test (POCT) in shortening the time-to-treatment, classifying stroke subtypes and improving patient's outcome. We first examine the conventional stroke management workflow, then highlight situations where a bedside biomarker assessment might aid clinical decision-making. A novel stroke POCT approach is presented, which combines the use of quantitative and multiplex POCT platforms for the detection of specific stroke biomarkers, as well as data-mining tools to drive analytical processes. Further work is needed in the development of POCTs to fulfill an unmet need in acute stroke management.

Elevated Serum High-Mobility Group Box-1 Protein Level Is Associated with Poor Functional Outcome in Ischemic Stroke

BACKGROUND

In experimental models, inhibition of high-mobility group box-1 (HMGB1) signaling has been reported to protect against the sequelae of ischemic stroke. Here, we determined the clinical significance of serum HMGB1 levels in patients with acute ischemic stroke.

METHODS

We enrolled 183 patients (114 men, 69 women; mean age: 72.7 years) over 6 consecutive months. On admission and day 7, we recorded the National Institutes of Health Stroke Scale scores and measured serum high-sensitivity C-reactive protein (hs-CRP) and HMGB1 levels. Stroke volumes were estimated using diffusion-weighted magnetic resonance imaging performed on admission. One year later, clinical outcome was assessed using the modified Rankin Scale (mRS).

RESULTS

Serum hs-CRP and HMGB1 levels in patients with ischemic stroke were increased relative to healthy controls (both P < .01). On day 7, hs-CRP, but not HMBG1, levels had increased significantly relative to levels at admission (P < .01 and .54, respectively). Higher HMGB1, but not hs-CRP, levels at day 7 correlated with larger stroke volumes (P < .01 and .28, respectively). HMGB1 levels did not significantly differ between stroke subtypes. Multiple logistic regression analysis indicated that a serum HMGB1 level higher than 7.5 ng/mL was an independent risk factor for poor prognosis, defined as a 1-year mRS score of 3-6 (odds ratio, 2.34; 95% confidence interval, 1.02-5.38).

CONCLUSIONS

Acute ischemic stroke is associated with elevated serum HMGB1 levels, and HMGB1 levels at admission independently predict poor outcome at 1 year. These results suggest that HMGB1 quantification provides more accurate prognostic information after ischemic stroke.

MR imaging in hyperacute ischemic stroke

Brain and vascular imaging are required components of the emergency assessment of patients with suspected stroke. Either CT or MRI may be used as the initial imaging test. MRI is more sensitive to the presence of acute and chronic ischemic lesions, and chronic microbleeds, but CT remains the most practical and used initial brain imaging test. Although, a non-enhanced CT or T2* MRI sequence showing no haemorrhage is sufficient for deciding intravenous treatment eligibility within the first 4.5h after stroke onset, a non-invasive intracranial vascular study is strongly recommended during the initial imaging evaluation of the acute stroke patient, particularly if mechanical thrombectomy is contemplated. Advanced imaging with multimodal MRI may facilitate accurate ischemic stroke diagnosis and characterization, and should be considered as an alternative to CT, especially for the selection of patients for acute reperfusion therapy in extended time windows, and in patients in which time of stroke onset is unknown. However, MRI should only be considered in the acute stroke workflow if centres are able to achieve speed and triaging efficiency similar to that which is currently available with CT-based imaging.

Peripheral blood AKAP7 expression as an early marker for lymphocyte-mediated post-stroke blood brain barrier disruption

Our group recently identified 16 genes whose peripheral blood expression levels are differentially regulated in acute ischemic stroke. The purpose of this study was to determine whether the early expression levels of any of these 16 genes are predictive for post-stroke blood brain barrier (BBB) disruption. Transcriptional expression levels of candidate genes were measured in peripheral blood sampled from ischemic stroke patients at emergency department admission, and BBB permeability was assessed at 24 hour follow up via perfusion-weighted imaging. Early heightened expression levels of AKAP7, a gene encoding a protein kinase A-binding scaffolding molecule, were significantly associated with BBB disruption 24 hours post-hospital admission. We then determined that AKAP7 is predominantly expressed by lymphocytes in peripheral blood, and strongly co-expressed with ITGA3, a gene encoding the adhesion molecule integrin alpha 3. Subsequent in vitro experiments revealed that heightened expression of AKAP7 and ITGA3 in primary human lymphocytes is associated with a highly adherent phenotype. Collectively, our results suggest that AKAP7 expression levels may have clinical utility as a prognostic biomarker for post-stroke BBB complications, and are likely elevated early in patients who later develop post-stroke BBB disruption due to the presence of an invasive lymphocyte population in the peripheral blood.

Tale of 2 Health-care Systems: Disparities in Demographic and Clinical Characteristics between 2 Ischemic Stroke Populations in Los Angeles County

BACKGROUND

Individuals who present to the emergency departments of safety-net systems often have poorly controlled risk factors due to lack of primary care. Little is known about potential differences in presenting characteristics, discharge medications, and discharge destinations of patients with acute ischemic stroke (AIS) who present to safety-net settings versus university medical centers (UMCs).

METHODS

Demographic characteristics, medical history, premorbid medication use, stroke severity, discharge medications, and discharge destination were assessed among consecutive admissions for AIS over a 2-year period at a UMC (n = 385) versus 2 university-affiliated safety-net hospitals (SNHs) (n = 346) in Los Angeles County.

RESULTS

Compared with patients presenting to the UMC, individuals admitted to the SNHs were younger, more frequently male, nonwhite, current smokers, hypertensive, and diabetic; they were less likely to take antithrombotics and statins before admission, and had worse serum lipid and glycemic markers (all P < .05). Patients admitted to the UMC trended toward more cardioembolic strokes and had higher stroke severity scores (P < .0001). At discharge, patients admitted to the SNHs were more likely to receive antihypertensive medications than do patients admitted to the UMC (P < .001), but there were no differences in prescription of antiplatelet medications or statins.

CONCLUSIONS

Individuals with AIS admitted to SNHs in Los Angeles County are younger and have poorer vascular risk factor control than their counterparts at a UMC. Discharge treatment does not vary considerably between systems. Early and more vigorous efforts at primary vascular risk reduction among patients seen at SNHs may be warranted to reduce disparities.

Ischemic stroke subtype is associated with outcome in thrombolyzed patients

OBJECTIVES

The impact of ischemic stroke subtype on clinical outcome in patients treated with intravenous tissue-type plasminogen activator (IV-tPA) is sparsely examined. We studied the association between stroke subtype and clinical outcome in magnetic resonance imaging (MRI)-evaluated patients treated with IV-tPA.

MATERIAL AND METHODS

We conducted a single-center retrospective analysis of MRI-selected stroke patients treated with IV-tPA between 2004 and 2010. The Trial of ORG 10172 in Acute Stroke Treatment criteria were used to establish the stroke subtype by 3 months. The outcomes of interest were a 3-month modified Rankin Scale score of 0-1 (favorable outcome), and early neurological improvement defined as complete remission of neurological deficit or improvement of ≥4 on the National Institute of Health Stroke Scale at 24 h. The outcomes among stroke subtypes were compared with multivariable logistic regression.

RESULTS

Among 557 patients, 202 (36%) had large vessel disease (LVD), 153 (27%) cardioembolic stroke (CE), 109 (20%) small vessel disease, and 93 (17%) were of other or undetermined etiology. Early neurological improvement was present in 313 (56.4%) patients, and 361 (64.8%) patients achieved a favorable outcome. Early neurological improvement and favorable outcome were more likely in CE patients compared with LVD patients (odds ratio (OR), 2.1 (95% confidence interval, 1.4-3.3), and 2.0 (95% confidence interval, 1.2-3.3), respectively).

CONCLUSIONS

Cardioembolic stroke patients were more likely to achieve early neurological improvement and favorable outcome compared with LVD stroke following MRI-based IV-tPA treatment. This finding may reflect a difference in the effect of IV-tPA among stroke subtypes.

Imaging in Endovascular Stroke Trials

Ischemic stroke remains a leading cause of death and disability worldwide. Various endovascular trials have addressed clinical outcomes without elucidating the impact of imaging studies in patient selection. The success of recent endovascular trials was bolstered by the use of advanced imaging techniques for optimal selection of reperfusion candidates. This seminal juncture in the history of stroke trials warrants further consideration on the use of imaging to guide future refinements in the treatment of acute stroke. In this article, we systematically review the imaging methodology and key facets used in all published endovascular stroke trials to date, discuss the success of recent trials using latest advanced imaging techniques and focus on the importance of imaging studies for future patient selection.

Plasma thrombin-cleaved osteopontin as a potential biomarker of acute atherothrombotic ischemic stroke

We investigated whether thrombin-cleaved osteopontin N-terminal is useful as a blood biomarker of acute atherothrombotic ischemic stroke. Acute ischemic stroke patients were prospectively evaluated with brain magnetic resonance imaging and cardiac evaluations for etiological diagnosis according to the Trial of Org 10172 in Acute Stroke Treatment classification. They were divided into the atherothrombotic and non-atherothrombotic groups. Thrombin-cleaved osteopontin N-terminal, osteopontin, matrix metalloproteinase-9, S100B, C-reactive protein and D-dimer levels were measured from blood samples collected at admission. After excluding patients who met the exclusion criteria or had stroke of other/undetermined etiology, 60 of the 100 patients initially enrolled were included in the final analysis. The ischemic stroke subtypes were atherothrombotic (n=28, 46.7%), cardioembolic (n=19, 31.7%) and lacunar (n=13, 21.7%). Thrombin-cleaved osteopontin N-terminal and matrix metalloproteinase-9 levels were significantly higher in the atherothrombotic than in the non-atherothrombotic group (median (interquartile range): 5.83  (0.0-8.6 ) vs. 0.0  (0.0-3.3) pmol l^-1, P=0.03 and 544   (322-749 ) vs. 343   (254-485) ng ml^-1, P=0.01, respectively). After adjustment for the prevalence of hypertension, diabetes and dyslipidemia, thrombin-cleaved osteopontin N-terminal levels of >5.47 pmol l^-1 (odds ratio, 16.81; 95% confidence interval, 3.53-80.10) and matrix metalloproteinase-9 levels of >605.5 ng ml^-1 (6.59; 1.77-24.60) were identified as independent predictors of atherothrombosis. Within 3 h from stroke onset, only thrombin-cleaved osteopontin N-terminal independently predicted atherothrombosis and thus may add valuable, time-sensitive diagnostic information in the early evaluation of ischemic stroke, especially the atherothrombotic subtype.

Increased Epicardial Fat Thickness Correlates with Aortic Stiffness and N-Terminal Pro-Brain Natriuretic Peptide Levels in Acute Ischemic Stroke Patients

Epicardial fat, a metabolically active tissue, has emerged as a risk factor and active player in metabolic and cardiovascular diseases. We investigated epicardial fat thickness in patients who had sustained an acute ischemic stroke, and we evaluated the relationship of epicardial fat thickness with other prognostic factors. We enrolled 61 consecutive patients (age, ≥18 yr) who had sustained a first acute ischemic stroke and had been admitted to our hospital within 24 hours of the onset of stroke symptoms. The control group comprised 82 consecutive sex- and age-matched patients free of past or current stroke who had been admitted to our cardiology clinics. Blood samples were taken for measurement of N-terminal pro-brain natriuretic peptide (NT-proBNP) levels at admission. Aortic stiffness indices and epicardial fat thickness were measured by means of transthoracic echocardiography within the first 48 hours. In comparison with the control group, the patients with acute ischemic stroke had significantly higher epicardial fat thickness (4.8 ± 0.9 vs 3.8 ± 0.7 mm; P <0.001), lower aortic distensibility (2.5 ± 0.8 vs 3.4 ± 0.9 cm(2) ·dyn(-1); P <0.001) and lower aortic strain (5.5% ± 1.9% vs 6.4% ± 1.8%; P=0.003). We found a significant association between epicardial fat thickness, NT-proBNP levels, and arterial dysfunction in patients who had sustained acute ischemic stroke. Increased epicardial fat thickness might be a novel risk factor and might enable evaluation of subclinical target-organ damage in these patients.

Age disparity in diagnostic evaluation of stroke patients: Embolic Stroke of Undetermined Source Global Registry Project

Introduction: Incomplete evaluation of stroke patients may result in an unclear diagnosis. Our objective was to determine if older stroke patients more often undergo incomplete diagnostic evaluations versus younger patients in an international cohort. Patients and methods: The Embolic Stroke of Undetermined Source Global Registry was a retrospective cohort of consecutive stroke patients evaluated at 19 stroke centers in 19 countries. Diagnostic evaluation was considered as complete if the patient had, at a minimum, brain computed tomography or magnetic resonance imaging with evidence of infarction, extracranial and intracranial vascular imaging, electrocardiography, ≥24 h of cardiac rhythm monitoring, and echocardiography. Patients were diagnosed with Embolic Stroke of Undetermined Source if brain imaging confirmed a nonlacunar infarction and no stroke etiology was determined after complete evaluation. Completeness of evaluation was compared between patients ≥75 versus <75 years old. Results: The registry included 2132 patients with recent ischemic stroke during 2013-2014, of which 349 were diagnosed with Embolic Stroke of Undetermined Source. Embolic Stroke of Undetermined Source patients ≥75 years were less likely to undergo brain magnetic resonance imaging (74% versus 89%, p = 0.001), transesophageal echocardiography (22% versus 39%, p = 0.005), and combination transthoracic and transesophageal echocardiography (16% versus 32%, p = 0.005) compared with Embolic Stroke of Undetermined Source patients <75 years. Discussion: Our study has identified an international age disparity in fundamental diagnostic testing for older patients with stroke of unknown etiology. Some testing biases were affected by geographic location (e.g., brain MRI was less frequently used in European ESUS patients), whereas other testing was implemented less frequently in the elderly regardless of location (e.g., transesophageal echocardiogram). Conclusion: Older patients in this international cohort had less sophisticated diagnostic testing for stroke, despite advanced age being well established as an independent risk factor for recurrent stroke. This was a global problem and further investigations are warranted to explore the cause.

Recurrent vascular events in lacunar stroke patients with metabolic syndrome and/or diabetes

OBJECTIVES

We used a prospective clinical trial to examine the risks conferred by metabolic syndrome (METS) and diabetes mellitus (DM) to recurrent strokes in the Secondary Prevention of Small Subcortical Strokes (SPS3) study cohort.

METHODS

The SPS3 trial enrolled 3,020 patients with lacunar strokes. Participants were stratified into groups of METS only, DM only, both, or neither using American Heart Association/National Heart, Lung, and Blood Institute and World Health Organization guidelines. Annualized event rates of strokes, myocardial infarction (MI), and all-cause mortality were calculated, and hazard ratios (HRs) referencing the “neither” group were computed, controlling for significantly associated baseline characteristics.

RESULTS

Among 2,999 participants, 25% had METS only, 6% had DM only, 32% had both conditions, and 37%had neither. Over a median of 3.8 years of follow-up, there were 274 recurrent strokes (240 ischemic, 34 hemorrhagic) and 74 MIs; among the 240 ischemic strokes, 134 (56%) were lacunar. The rates of any recurrent stroke (HR 1.7, 95% confidence interval [CI] 1.3–2.3) or lacunar stroke (HR 2.4, 95% CI 1.5–3.7) were significantly higher for those with concurrent METS and DM compared with those who had neither. Risk of incident MI was higher in participants with DM (HR 2.8, 95% CI 1.1–7.0) or concurrent DM and METS (HR 2.6, 95% CI 1.4–4.9).

CONCLUSION

METS and DM were significant comorbid conditions in lacunar stroke patients and they were associated with stroke recurrence. In patients with lacunar infarcts, a vigilant approach to prevent development of DM in those with METS may be a potential strategy to reduce recurrent strokes.

Magnetic Resonance Imaging in Ischemic Stroke and Cerebral Venous Thrombosis

Imaging is indispensable in the evaluation of patients presenting with central nervous system emergencies. Although computed tomography (CT) is the mainstay of initial assessment and triage, magnetic resonance imaging (MRI) has become vital in expanding diagnostic capabilities, refining management strategies, and developing our understanding of disease processes. Ischemic stroke and cerebral venous thrombosis are 2 areas wherein MRI is actively revolutionizing patient care. Familiarity with the imaging manifestations of these 2 disease processes is crucial for any radiologist reading brain MR studies. In this review, the fundamentals of image interpretation will be addressed in-depth. Furthermore, advanced imaging techniques which are redefining the role of emergency MRI will be outlined, with a focus on the pathophysiological mechanisms that underlie image interpretation. In particular, emerging data surrounding the use of MR perfusion imaging in acute stroke management portend dramatic shifts in neurointerventional management. To this end, a review of the recent stroke literature will hopefully enhance the radiologist's role in both meaningful reporting and multidisciplinary teamwork.

Recovery Potential After Acute Stroke

In acute stroke, the major factor for recovery is the early use of thrombolysis aimed at arterial recanalization and reperfusion of ischemic brain tissue. Subsequently, neurorehabilitative training critically improves clinical recovery due to augmention of postlesional plasticity. Neuroimaging and electrophysiology studies have revealed that the location and volume of the stroke lesion, the affection of nerve fiber tracts, as well as functional and structural changes in the perilesional tissue and in large-scale bihemispheric networks are relevant biomarkers of post-stroke recovery. However, associated disorders, such as mood disorders, epilepsy, and neurodegenerative diseases, may induce secondary cerebral changes or aggravate the functional deficits and, thereby, compromise the potential for recovery.

Frequency of left atrial dilatation in ischemic stroke

OBJECTIVE

The study aimed to evaluate the frequency of left atrial dilatation in cases of first-ever acute ischemic stroke with or without atrial fibrillation in a cohort of patients hospitalized for ischemic stroke.

METHODS

Files of 120 patients admitted to our hospital with the diagnosis of acute ischemic stroke were investigated. All patients had at least one brain imaging. Etiology of stroke was categorized according to Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification. Transthoracic and/or transoesophageal echocardiography was used to measure left atrium size. Optimal cut-off value of left atrial diameter was determined as 4 cm. SPSS 11.5 was used for statistical analyses.

RESULTS

In 40% of the patients, left atrial dilatation was detected. Nineteen patients with left atrial dilatation had atrial fibrillation, which was statistically significant (p<0.05). Ninety-four (30.8%) patients with no atrial fibrillation had left atrial dilatation. In the TOAST classification trial, as a statistically significant finding, left atrial dilatation was detected 68.9% of the patients with cardioembolic infarcts. The most frequently encountered risk factor in patients was hypertension.

CONCLUSION

Left atrial dilatation is an important marker for cerebrovascular diseases, and if accompanied by atrial fibrillation becomes even more significant.