Magnetic resonance imaging versus computed tomography for detection of acute vascular lesions in patients presenting with stroke symptoms

Biochemical, biomechanical and imaging biomarkers of ischemic stroke: Time for integrative thinking

Stroke is one of the leading causes of adult disability affecting millions of people worldwide. Post-stroke cognitive and motor impairments diminish quality of life and functional independence. There is an increased risk of having a second stroke and developing secondary conditions with long-term social and economic impacts. With increasing number of stroke incidents, shortage of medical professionals and limited budgets, health services are struggling to provide a care that can break the vicious cycle of stroke. Effective post-stroke recovery hinges on holistic, integrative and personalized care starting from improved diagnosis and treatment in clinics to continuous rehabilitation and support in the community. To improve stroke care pathways, there have been growing efforts in discovering biomarkers that can provide valuable insights into the neural, physiological and biomechanical consequences of stroke and how patients respond to new interventions. In this review paper, we aim to summarize recent biomarker discovery research focusing on three modalities (brain imaging, blood sampling and gait assessments), look at some established and forthcoming biomarkers, and discuss their usefulness and complementarity within the context of comprehensive stroke care. We also emphasize the importance of biomarker guided personalized interventions to enhance stroke treatment and post-stroke recovery.

Imaging Biomarkers of VCI: A Focused Update

Vascular cognitive impairment is common after stroke, in memory clinics, medicine for the elderly services, and undiagnosed in the community. Vascular disease is said to be the second most common cause of dementia after Alzheimer disease, yet vascular dysfunction is now known to predate cognitive decline in Alzheimer disease, and most dementias at older ages are mixed. Neuroimaging has a major role in identifying the proportion of vascular versus other likely pathologies in patients with cognitive impairment. Here, we aim to provide a pragmatic but evidence-based summary of the current state of potential imaging biomarkers, focusing on magnetic resonance imaging and computed tomography, which are relevant to diagnosing, estimating prognosis, monitoring vascular cognitive impairment, and incorporating our own experiences. We focus on markers that are well-established, with a known profile of association with cognitive measures, but also consider more recently described, including quantitative tissue markers of vascular injury. We highlight the gaps in accessibility and translation to more routine clinical practice.

Exploring the role of in-patient magnetic resonance imaging use among admitted ischemic stroke patients in improving patient outcomes and reducing healthcare resource utilization

Purpose

Despite the diagnostic and etiological significance of in-patient MRI in ischemic stroke (IS), its utilization is considered resource-intensive, expensive, and thus limiting feasibility and relevance. This study investigated the utilization of in-patient MRI for IS patients and its impact on patient and healthcare resource utilization outcomes.

Methods

This retrospective registry-based study analyzed 1,956 IS patients admitted to Halifax's QEII Health Centre between 2015 and 2019. Firstly, temporal trends of MRI and other neuroimaging utilization were evaluated. Secondly, we categorized the cohort into two groups (MRI vs. No MRI; in addition to a non-contrast CT) and investigated adjusted differences in patient outcomes at admission, discharge, and post-discharge using logistic regression. Additionally, we analyzed healthcare resource utilization using Poisson log-linear regression. Furthermore, patient outcomes significantly associated with MRI use underwent subgroup analysis for stroke severity (mild stroke including transient ischemic attack vs. moderate and severe stroke) and any acute stage treatment (thrombolytic or thrombectomy or both vs. no treatment) subgroups, while using an age and sex-adjusted logistic regression model.

Results

MRI was used in 40.5% patients; non-contrast CT in 99.3%, CT angiogram in 61.8%, and CT perfusion in 50.3%. Higher MRI utilization was associated with male sex, younger age, mild stroke, wake-up stroke, and no thrombolytic or thrombectomy treatment. MRI use was independently associated with lower in-hospital mortality (adjusted OR, 0.23; 95% CI, 0.15-0.36), lower symptomatic neurological status changes (0.64; 0.43-0.94), higher home discharge (1.32; 1.07-1.63), good functional outcomes at discharge (mRS score 0-2) (1.38; 1.11-1.72), lower 30-day stroke re-admission rates (0.48; 0.26-0.89), shorter hospital stays (regression coefficient, 0.92; 95% CI, 0.90-0.94), and reduced direct costs of hospitalization (0.90; 0.89-0.91). Subgroup analysis revealed significantly positive association of MRI use with most patient outcomes in moderate and severe strokes subgroup and non-acutely treated subgroup. Conversely, outcomes in mild strokes (including TIAs) subgroup and acute treatment subgroup were comparable regardless of MRI use.

Conclusion

A substantial proportion of admitted IS patients underwent MRI, and MRI use was associated with improved patient outcomes and reduced healthcare resource utilization. Considering the multifactorial nature of IS patient outcomes, further randomized controlled trials are suggested to investigate the role of increased MRI utilization in optimizing in-patient IS management.

Poststroke Executive Function in Relation to White Matter Damage on Clinically Acquired CT Brain Imaging

BACKGROUND

Executive function (EF) impairments are prevalent post stroke and are associated with white matter (WM) damage on MRI. However, less is known about the relationship between poststroke EF and WM damage on CT imaging.

OBJECTIVE

To investigate the relationship between poststroke EF and WM damage associated with stroke lesions and WM hypointensities (WMHs) on clinically acquired CT imaging.

METHOD

This study analyzed data from the Oxford Cognitive Screening Program, which recruited individuals aged ≥18 years with a confirmed stroke from an acute stroke unit. The individuals completed a follow-up assessment 6 months post stroke. We included individuals with a CT scan showing a visible stroke who completed follow-up EF assessment using the Oxford Cognitive Screen-Plus rule-finding task. We manually delineated stroke lesions and quantified then dichotomized WM damage caused by the stroke using the HCP-842 atlas. We visually rated then dichotomized WMHs using the Age-Related White Matter Changes Scale.

RESULTS

Among 87 stroke survivors (M age = 73.60 ± 11.75; 41 female; 61 ischemic stroke), multivariable linear regression showed that stroke damage to the medial lemniscus ( B = -8.86, P < 0.001) and the presence of WMHs ( B = -5.42, P = 0.005) were associated with poorer EF 6 months post stroke after adjusting for covariates including age and education.

CONCLUSION

Poorer EF was associated with WM damage caused by stroke lesions and WMHs on CT. These results confirm the importance of WM integrity for EF post stroke and demonstrate the prognostic utility of CT-derived imaging markers for poststroke cognitive outcomes.

Prevalence of Arm Weakness, Pre-Stroke Outcomes and Other Post-Stroke Impairments Using Routinely Collected Clinical Data on an Acute Stroke Unit

INTRODUCTION

The prevalence of upper limb motor weakness early post-stroke may be changing, which can have clinical and research implications. Our primary aim was to describe the prevalence of upper limb motor weakness early post-stroke, with a secondary aim to contextualize this prevalence by describing pre-stroke outcomes, other post-stroke impairments, functional activities, and discharge destination.

METHODS

This cross-sectional observational study extracted clinical data from confirmed stroke patients admitted to a metropolitan stroke unit over 15-months. The primary upper limb weakness measure was Shoulder Abduction and Finger Extension (SAFE) score. Demographics (eg, age), clinical characteristics (eg, stroke severity), pre-stroke outcomes (eg, clinical frailty), other post-stroke impairments (eg, command following), functional activities (eg, ambulation), and discharge destination were also extracted.

RESULTS

A total of 463 participants had a confirmed stroke and SAFE score. One-third of patients received ≥1 acute medical intervention(s). Nearly one-quarter of patients were classified as frail pre-stroke. Upper limb weakness (SAFE≤8) was present in 35% [95% CI: 30%-39%] at a median of 1-day post-stroke, with 22% presenting with mild-moderate weakness (SAFE5-8). The most common other impairments were upper limb coordination (46%), delayed recall (41%), and upper limb sensation (26%). After a median 3-day acute stroke stay, 52% of the sample were discharged home.

CONCLUSION

Upper limb weakness was present in just over a third (35%) of the sample early post-stroke. Data on pre-stroke outcomes and the prevalence of other post-stroke impairments highlights the complexity and heterogeneity of stroke recovery. Further research is required to tease out meaningful recovery phenotypes and their implications.

Association of Neuroimaging Markers on Clinical CT Scans With Domain-Specific Cognitive Impairment in the Early and Later Poststroke Stages

BACKGROUND AND OBJECTIVES

Poststroke cognitive impairment (PSCI) is associated with neuroimaging markers, including cortical atrophy and white matter lesions (WMLs), on clinically acquired CT neuroimaging. The objective was to investigate the association between cortical atrophy/WMLs and PSCI in specific cognitive domains in the acute/subacute and chronic stages after stroke, to provide clarity on the relationship between these neuroimaging markers and the temporal evolution of PSCI.

METHODS

We visually assessed cortical atrophy using the Global Cortical Atrophy (GCA) scale and WMLs using the Fazekas scale. Oxford Cognitive Screen or Birmingham Cognitive Screen assessed PSCI at 2 time points (acute/subacute and chronic) in 6 domains (language, memory, number processing, executive function, attention, and praxis). We binarized domain-specific performance as impaired/unimpaired using normative cutoffs. Multivariable linear and logistic regression analyses evaluated associations between GCA/Fazekas scores with acute/subacute and chronic global and domain-specific PSCI, and ANCOVAs examined whether these scores were significantly different in patients with recovered vs persistent PSCI. Age, sex, education, NIHSS, lesion volume, and recurrent stroke were covariates in these analyses.

RESULTS

Among 411 stroke patients (Mdn/IQR age = 76.16/66.84-83.47; 193 female; 346 ischemic stroke; 107 recurrent stroke), GCA and Fazekas scores were not associated with global cognitive impairment in the acute/subacute stage after stroke, but GCA score was associated with chronic global PSCI (B = 0.01, p < 0.001, 95% CI 0.00-0.01). In domain-specific analyses, GCA score was associated with chronic impairment in the memory (B = 0.06, p < 0.001, 95% CI 0.03-0.10) and attention (B = 0.05, p = 0.003, 95% CI 0.02-0.09) domains, and in patients with persistent PSCI, these domains showed significantly higher GCA scores than patients who had recovered (memory: F(1, 157) = 6.63, p = 0.01, η 2 G = 0.04; attention: F(1, 268) = 10.66, p = 0.001, η 2 G = 0.04).

DISCUSSION

This study highlights the potential effect of cortical atrophy on the cognitive recovery process after stroke and demonstrates the prognostic utility of CT neuroimaging for poststroke cognitive outcomes. Clinical neuroimaging could help identify patients at long-term risk of PSCI during acute hospitalization.

Neuroimaging of Acute Ischemic Stroke: Multimodal Imaging Approach for Acute Endovascular Therapy

Advances in acute ischemic stroke (AIS) treatment have been contingent on innovations in neuroimaging. Neuroimaging plays a pivotal role in the diagnosis and prognosis of ischemic stroke and large vessel occlusion, enabling triage decisions in the emergent care of the stroke patient. Current imaging protocols for acute stroke are dependent on the available resources and clinicians' preferences and experiences. In addition, differential application of neuroimaging in medical decision-making, and the rapidly growing evidence to support varying paradigms have outpaced guideline-based recommendations for selecting patients to receive intravenous or endovascular treatment. In this review, we aimed to discuss the various imaging modalities and approaches used in the diagnosis and treatment of AIS.

Clinical feasibility of diffusion microstructure imaging (DMI) in acute ischemic stroke

BACKGROUND

Diffusion microstructure imaging (DMI) is a fast approach to higher-order diffusion-weighted magnetic resonance imaging that allows robust decomposition and characterization of diffusion properties of brain tissue into intra-axonal, extra-axonal, and a free water-compartment. We now report the application of this technique to acute ischemic stroke and demonstrate its potential applicability to the daily clinical routine.

METHODS

Thirty-eight patients diagnosed with acute ischemic stroke were scanned using an accelerated multi-shell diffusion-weighted imaging protocol (median delay between onset and MRI scan of 113 min). DMI metrics were calculated and the apparent diffusion coefficient (ADC) derived from conventional diffusion-weighted imaging was used for comparison. The resulting DMI parameter maps were analysed for their potential to improve infarct core delineation, and a receiver-operating characteristic (ROC) analysis was subsequently performed for automated infarct segmentation.

RESULTS

Robust parameter maps for diffusion microstructure properties were obtained in all cases. Within the ischemic tissue, an increase in the volume fraction of the intra-axonal compartment was accompanied by a volume fraction reduction in the other two compartments. Moreover, diffusivity was reduced in all three compartments, with intra-axonal diffusivity showing the highest degree of contrast. The intra-axonal diffusion coefficient maps were subsequently found to perform better than single-shell ADC-derived segmentation in terms of automatic segmentation of the infarct core (area under the curve = 0.98 vs 0.92).

CONCLUSIONS

The alterations to the ischemic core detected by DMI are in line with the "beading-model" of non-uniform neurite swelling under ischemic conditions. When compared to conventional single-shell diffusion-weighted imaging, DMI metrics are associated with improved discriminative power for delineating and characterizing ischemic changes. This might allow a more detailed assessment of infarct age, severity of damage, the degree of reversibility, and outcome.

Sheared two-dimensional radiofrequency excitation for off-resonance robustness and fat suppression in reduced field-of-view imaging

PURPOSE

Two-dimensional (2D) echo-planar radiofrequency (RF) pulses are widely used for reduced field-of-view (FOV) imaging in applications such as diffusion-weighted imaging. However, long pulse durations render the 2D RF pulses sensitive to off-resonance effects, causing local signal losses in reduced-FOV images. This work aims to achieve off-resonance robustness for 2D RF pulses via a sheared trajectory design.

THEORY AND METHODS

A sheared 2D RF pulse design is proposed to reduce pulse durations while covering identical excitation k-space extent as a standard 2D RF pulse. For a given shear angle, the number of sheared trajectory lines is minimized to obtain the shortest pulse duration, such that the excitation replicas are repositioned outside the slice stack to guarantee unlimited slice coverage. A target fat/water signal ratio of 5% is chosen to achieve robust fat suppression.

RESULTS

Simulations, imaging experiments on a custom head and neck phantom, and in vivo imaging experiments in the spinal cord at 3 T demonstrate that the sheared 2D RF design provides significant improvement in image quality while preserving profile sharpnesses. In regions with high off-resonance effects, the sheared 2D RF pulse improves the signal by more than 50% when compared to the standard 2D RF pulse.

CONCLUSION

The proposed sheared 2D RF design successfully reduces pulse durations, exhibiting significantly improved through-plane off-resonance robustness, while providing unlimited slice coverage and high fidelity fat suppression. This method will be especially beneficial in regions suffering from a variety of off-resonance effects, such as spinal cord and breast.

Silent Brain Infarction, Delirium, and Cognition in Three Invasive Cardiovascular Procedures: a Systematic Review

Silent brain infarctions (SBIs) are brain lesions noted on neuroimaging that are not associated with clinical symptoms. SBIs are associated with a number of vascular risk factors and are common following invasive cardiovascular procedures such as atrial fibrillation (AF) ablation, coronary artery bypass graft (CABG), and transcatheter aortic valve replacement (TAVR). Although not eliciting signs of clinical stroke, SBIs are associated with increased frailty, and motor and mood features. Less is known, however, about the relationship between SBI, cognition, and delirium following invasive cardiac procedures and most investigations into these relationships have been reported in large-scale epidemiological studies. In the current paper, we conducted a systematic review to evaluate evidence of a relationship between SBI, delirium, and cognitive decline following CABG, AF ablation, and TAVR. Twenty studies met inclusion criteria. In general, our review identified conflicting results for each cardiac procedure, with some studies suggesting a relationship between SBI, cognitive impairment, and delirium, whereas others showed no relationship between SBI, cognitive impairment, and delirium. Potential reasons for this discrepancy as well as suggestions for future research are discussed.

Unruptured Arteriovenous Malformations in the Multidetector Computed Tomography Era: Frequency of Detection and Predictable Failures

Objectives:

While hemorrhage arising from ruptured arteriovenous malformations (AVMs) is usually evident on multidetector non-contrast computed tomography (NCCT), unruptured AVMs can be below the limits of detection. We performed a retrospective review of NCCT of patients with a proven diagnosis of unruptured AVM to determine if advances in CT technology have made them more apparent and what features predict their detection.

Material and Methods:

Twenty-five NCCTs met inclusion criteria of having angiography or MR proven AVM without hemorrhage, prior surgery, or other CNS disease. Demographic variables, clinical symptoms at presentation, abnormal CT imaging findings, attenuation of the superior sagittal sinus (SSS), and Spetzler-Martin grade of each AVM were recorded. We examined the relationship between AVM detection and SSS attenuation through Kruskal–Wallis test. Exploratory serial logistic principal components analysis was performed including demographics, symptoms, and CT features in the multivariate model.

Results:

About 80% of the NCCTs showed an abnormality while 20% were normal. All those with an identifiable abnormality showed hyperdensity (80%). Logistic regression models indicate that clustered associations between several CT features, primarily calcifications, hyperdensity, and vascular prominence significantly predicted Spetzler-Martin grade (likelihood ratio 7.7, P = 0.006). SSS attenuation was significantly lower in subjects with occult AVMs when compared to those with CT abnormalities (median 47 vs. 55 HU, P < 0.04).

Conclusion:

Abnormal hyperdensity was evident in all detectable cases (80%) and multiple CT features were predictive of a higher Spetzler-Martin AVM grade. Moreover, SSS attenuation less than 50 HU was significantly correlated with a false-negative NCCT.

Comparison of magnetic resonance imaging versus computed tomography-based thrombolysis treatment in patients with acute ischemic stroke

PURPOSE

To evaluate the efficacy and safety of magnetic resonance imaging (MRI)-based comparing with computed tomography (CT)-based selection for intravenous thrombolysis in patients with acute ischemic stroke (AIS).

METHODS

Totally 462 consecutive AIS patients treated with intravenous thrombolysis within a 4.5 h window from Jan. 2016 to Dec. 2019 were enrolled. The primary endpoint was the good functional outcome defined by a modified Rankin Scale (mRS) of 0-2 at 3 months. Secondary outcomes include the excellent functional outcome defined by a mRS of 0-1 at 3 months, occurrences of symptomatic intracranial hemorrhage (SICH), 7-day mortality, and 3-month mortality.

RESULTS

Overall 172 patients received MRI and 290 received CT before they were treated with thrombolysis. The difference in the good or excellent functional outcome was not statistically significant between MRI and CT groups (both P > 0.05). The incidences of 7-day mortality (3.5% vs. 8.6%, P < 0.01), 30-day mortality (12.8% vs. 21.0%, P = 0.03), and SICH (12.2% vs. 20.3%, P < 0.01) were obviously lower for MRI-based regimen compared with CT-based regimen. Multivariate logistic regression indicated that MRI-based regimen was significantly associated with a lower risk of 7-day mortality (OR = 0.72, 95% CI: 0.53-0.91; P < 0.01), 30-day mortality (OR = 0.58, 95% CI: 0.47-0.73; P < 0.01), and SICH (OR = 0.44, 95% CI: 0.20-0.65; P < 0.01) after controlling for potential confounding factors.

CONCLUSION

Despite MRI-based thrombolysis was not demonstrated to be associated with the good functional outcome, it significantly reduced risks of mortality and SICH in patients with AIS compared with CT-based thrombolysis.

A Review on Computer Aided Diagnosis of Acute Brain Stroke

Amongst the most common causes of death globally, stroke is one of top three affecting over 100 million people worldwide annually. There are two classes of stroke, namely ischemic stroke (due to impairment of blood supply, accounting for ~70% of all strokes) and hemorrhagic stroke (due to bleeding), both of which can result, if untreated, in permanently damaged brain tissue. The discovery that the affected brain tissue (i.e., 'ischemic penumbra') can be salvaged from permanent damage and the bourgeoning growth in computer aided diagnosis has led to major advances in stroke management. Abiding to the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines, we have surveyed a total of 177 research papers published between 2010 and 2021 to highlight the current status and challenges faced by computer aided diagnosis (CAD), machine learning (ML) and deep learning (DL) based techniques for CT and MRI as prime modalities for stroke detection and lesion region segmentation. This work concludes by showcasing the current requirement of this domain, the preferred modality, and prospective research areas.

Imaging selection for reperfusion therapy in acute ischemic stroke beyond the conventional time window

Originally, the efficacy of acute ischemic stroke treatment with thrombolysis or thrombectomy was only proven in narrow time windows of, respectively, 4.5 and 6 h after onset. Introducing imaging-based selection beyond non-contrast enhanced computed tomography has expanded the treatment window, focusing on presumed tissue status rather than solely on time after stroke onset. Different mismatch concepts have been adopted in clinical practice to select patients in the extended and unknown time window based on findings from randomized controlled trials. Since various concepts exist that can identify patients likely to benefit from reperfusion strategies, clinicians may wonder which imaging modality may be preferred in the emergency setting. In this review, we will discuss the different mismatch concepts and their practical implementation for patient selection for thrombolysis or thrombectomy, beyond the conventional time window.

Preferred reporting items for journal and conference abstracts of systematic reviews and meta-analyses of diagnostic test accuracy studies (PRISMA-DTA for Abstracts): checklist, explanation, and elaboration

For many users of the biomedical literature, abstracts may be the only source of information about a study. Hence, abstracts should allow readers to evaluate the objectives, key design features, and main results of the study. Several evaluations have shown deficiencies in the reporting of journal and conference abstracts across study designs and research fields, including systematic reviews of diagnostic test accuracy studies. Incomplete reporting compromises the value of research to key stakeholders. The authors of this article have developed a 12 item checklist of preferred reporting items for journal and conference abstracts of systematic reviews and meta-analyses of diagnostic test accuracy studies (PRISMA-DTA for Abstracts). This article presents the checklist, examples of complete reporting, and explanations for each item of PRISMA-DTA for Abstracts.

Acute intracerebral haemorrhage: diagnosis and management

Intracerebral haemorrhage (ICH) accounts for half of the disability-adjusted life years lost due to stroke worldwide. Care pathways for acute stroke result in the rapid identification of ICH, but its acute management can prove challenging because no individual treatment has been shown definitively to improve its outcome. Nonetheless, acute stroke unit care improves outcome after ICH, patients benefit from interventions to prevent complications, acute blood pressure lowering appears safe and might have a modest benefit, and implementing a bundle of high-quality acute care is associated with a greater chance of survival. In this article, we address the important questions that neurologists face in the diagnosis and acute management of ICH, and focus on the supporting evidence and practical delivery for the main acute interventions.

Application of neutrophil to lymphocyte ratio to identify CT-negative cerebral infarction with nonfocal symptoms

Background

The neutrophil to lymphocyte ratio (NLR) has emerged as a strong predictor of mortality in stroke patients. Our study aimed to investigate the correlation between NLR and cerebral infarction with nonfocal symptoms confirmed by diffusion-weighted imaging (DWI) (+).

Methods

A total of 439 patients with nonfocal stroke symptoms with CT-negative findings were included from January 1 to December 31, 2018. All patients underwent a head MRI examination within seven days following a head CT examination. The patients’ demographics, medical history, presenting symptoms, and stroke location were recorded. Logistic regression and receiver operating characteristic (ROC) curve analysis were used to identify variables with a significant association with cerebral infarction.

Results

Cerebral infarction was detected in 79 (18%) patients confirmed by DWI(+), located mostly in the cerebellum (40.51%). Dizziness (85.19%) was the most common symptom. The cerebral infarction group showed a higher prevalence of hypertension (P<0.0001), diabetes mellitus (P<0.0001), and smoking status (P=0.001) than non-cerebral infarction group. The NLR (P<0.0001) was higher in the cerebral infarction group. There was no significant difference in NIHSS (P=0.09). Logistic analysis revealed that male gender (P=0.046), a history of hypertension (P=0.001), diabetes mellitus (P=0.001), smoking (P=0.023), and NLR (P<0.0001) were the best predictors of cerebral infarction. When integrating sex, hypertension, diabetes mellitus, smoking and NLR, the area under ROC value of the combined method was 0.785, higher than any separate parameters (P<0.05).

Conclusions

NLR combined with male gender, a history of hypertension, diabetes mellitus, and smoking, could predict DWI-confirmed cerebral infarction with nonfocal neurologic symptoms with high diagnostic accuracy.

External validation of stroke mimic prediction scales in the emergency department

BACKGROUND

Acute ischemic stroke is a time-sensitive emergency where accurate diagnosis is required promptly. Due to time pressures, stroke mimics who present with similar signs and symptoms as acute ischemic stroke, pose a diagnostic challenge to the emergency physician. With limited access to investigative tools, clinical prediction, tools based only on clinical features, may be useful to identify stroke mimics. We aim to externally validate the performance of 4 stroke mimic prediction scales, and derive a novel decision tree, to improve identification of stroke mimics.

METHODS

We performed a retrospective cross-sectional study at a primary stroke centre, served by a telestroke hub. We included consecutive patients who were administered intravenous thrombolysis for suspected acute ischemic stroke from January 2015 to October 2017. Four stroke mimic prediction tools (FABS, simplified FABS, Telestroke Mimic Score and Khan Score) were rated simultaneously, using only clinical information prior to administration of thrombolysis. The final diagnosis was ascertained by an independent stroke neurologist. Area under receiver operating curve (AUROC) analysis was performed. A classification tree analysis was also conducted using variables which were found to be significant in the univariate analysis.

RESULTS

Telestroke Mimic Score had the highest discrimination for stroke mimics among the 4 scores tested (AUROC = 0.75, 95% CI = 0.63-0.87). However, all 4 scores performed similarly (DeLong p > 0.05). Telestroke Mimic Score had the highest sensitivity (91.3%), while Khan score had the highest specificity (88.2%). All 4 scores had high positive predictive value (88.1 to 97.5%) and low negative predictive values (4.7 to 32.3%). A novel decision tree, using only age, presence of migraine and psychiatric history, had a higher prediction performance (AUROC = 0.80).

CONCLUSION

Four tested stroke mimic prediction scales performed similarly to identify stroke mimics in the emergency setting. A novel decision tree may improve the identification of stroke mimics.

Proposed Standardized Neurological Endpoints for Cardiovascular Clinical Trials: An Academic Research Consortium Initiative

Surgical and catheter-based cardiovascular procedures and adjunctive pharmacology have an inherent risk of neurological complications. The current diversity of neurological endpoint definitions and ascertainment methods in clinical trials has led to uncertainties in the neurological risk attributable to cardiovascular procedures and inconsistent evaluation of therapies intended to prevent or mitigate neurological injury. Benefit-risk assessment of such procedures should be on the basis of an evaluation of well-defined neurological outcomes that are ascertained with consistent methods and capture the full spectrum of neurovascular injury and its clinical effect. The Neurologic Academic Research Consortium is an international collaboration intended to establish consensus on the definition, classification, and assessment of neurological endpoints applicable to clinical trials of a broad range of cardiovascular interventions. Systematic application of the proposed definitions and assessments will improve our ability to evaluate the risks of cardiovascular procedures and the safety and effectiveness of preventive therapies.

2019 Update of the Korean Clinical Practice Guidelines of Stroke for Endovascular Recanalization Therapy in Patients with Acute Ischemic Stroke

Endovascular recanalization therapy (ERT) has been a standard of care for patients with acute ischemic stroke due to large artery occlusion (LAO) within 6 hours after onset, since five landmark ERT trials conducted by 2015 demonstrated its clinical benefit. Recently, two randomized clinical trials demonstrated that ERT, even in the late time window of up to 16 hours or 24 hours after last known normal time, improved the outcome of patients who had a target mismatch, defined as either clinical-core mismatch or perfusion-core mismatch, which prompted the update of national guidelines in several countries. Accordingly, to provide evidence-based and up-to-date recommendations for ERT in patients with acute LAO in Korea, the Clinical Practice Guidelines Committee of the Korean Stroke Society decided to revise the previous Korean Clinical Practice Guidelines of Stroke for ERT. For this update, the members of the writing group were appointed by the Korean Stroke Society and the Korean Society of Interventional Neuroradiology. After thoroughly reviewing the updated evidence from two recent trials and relevant literature, the writing members revised recommendations, for which formal consensus was achieved by convening an expert panel composed of 45 experts from the participating academic societies. The current guidelines are intended to help healthcare providers, patients, and their caregivers make well-informed decisions and to improve the quality of care regarding ERT. The ultimate decision for ERT in a particular patient must be made in light of circumstances specific to that patient.

2019 Update of the Korean Clinical Practice Guidelines of Stroke for Endovascular Recanalization Therapy in Patients with Acute Ischemic Stroke

Endovascular recanalization therapy (ERT) has been a standard of care for patients with acute ischemic stroke due to large artery occlusion (LAO) within 6 hours after onset, since five landmark ERT trials conducted by 2015 demonstrated its clinical benefit. Recently, two randomized clinical trials demonstrated that ERT, even in the late time window of up to 16 hours or 24 hours after last known normal time, improved the outcome of patients who had a target mismatch, defined as either clinical-core mismatch or perfusion-core mismatch, which prompted the update of national guidelines in several countries. Accordingly, to provide evidence-based and up-to-date recommendations for ERT in patients with acute LAO in Korea, the Clinical Practice Guidelines Committee of the Korean Stroke Society decided to revise the previous Korean Clinical Practice Guidelines of Stroke for ERT. For this update, the members of the writing group were appointed by the Korean Stroke Society and the Korean Society of Interventional Neuroradiology. After thoroughly reviewing the updated evidence from two recent trials and relevant literature, the writing members revised recommendations, for which formal consensus was achieved by convening an expert panel composed of 45 experts from the participating academic societies. The current guidelines are intended to help healthcare providers, patients, and their caregivers make well-informed decisions and to improve the quality of care regarding ERT. The ultimate decision for ERT in a particular patient must be made in light of circumstances specific to that patient.

Clinical diagnosis of TIA or minor stroke and prognosis in patients with neurological symptoms: A rapid access clinic cohort

BACKGROUND

The long-term risk of stroke or myocardial infarction (MI) in patients with minor neurological symptoms who are not clinically diagnosed with transient ischaemic attack (TIA) or minor stroke is uncertain.

METHODS

We used data from a rapid access clinic for patients with suspected TIA or minor stroke and follow-up from four overlapping data sources for a diagnosis of ischaemic or haemorrhagic stroke, MI, major haemorrhage and death. We identified patients with and without a clinical diagnosis of TIA or minor stroke. We estimated hazard ratios of stroke, MI, major haemorrhage and death in early and late time periods.

RESULTS

5,997 patients were seen from 2005-2013, who were diagnosed with TIA or minor stroke (n = 3604, 60%) or with other diagnoses (n = 2392, 40%). By 5 years the proportion of patients who had a subsequent ischaemic stroke or MI, in patients with a clinical diagnosis of minor stroke or TIA was 19% [95% confidence interval (CI): 17-20%], and in patients with other diagnoses was 10% (95%CI: 8-15%). Patients with clinical diagnosis of TIA or minor stroke had three times the hazard of stroke or MI compared to patients with other diagnoses [hazard ratio (HR)2.83 95%CI:2.13-3.76, adjusted age and sex] by 90 days post-event; however from 90 days to end of follow up, this difference was attenuated (HR 1.52, 95%CI:1.25-1.86). Older patients and those who had a history of vascular disease had a high risk of stroke or MI, whether or not they were diagnosed with minor stroke or TIA.

CONCLUSIONS

Careful attention to vascular risk factors in patients presenting with transient or minor neurological symptoms not thought to be due to stroke or TIA is justified, particularly those who are older or have a history of vascular disease.

[Imaging in acute ischemic stroke using automated postprocessing algorithms]

There are several automated analytical methods to detect thromboembolic vascular occlusions, the infarct core and the potential infarct-endangered tissue (tissue at risk) by means of multimodal computed tomography (CT) and magnetic resonance imaging (MRI). The infarct core is more reliably visualized by diffusion-weighted imaging (DWI) MRI or CT perfusion than by native CT. The extent of tissue at risk and endangerment can only be estimated; however, it seems essential whether "tissue at risk" actually exists. To ensure consistent patient care, uniform imaging protocols should be acquired in the referring hospital and thrombectomy center and the collected data should be standardized and automatically evaluated and presented. Whether patients with a large infarct core and with or without tissue at risk or patients with large vessel occlusion (LVO) but low NIHSS benefit from thrombectomy has to be evaluated in controlled clinical trials using standardized imaging protocols. A promising, potentially time-saving approach is also native CT and CT angiography using a flat-panel detector angiography system for assessment of vessel occlusion and leptomeningeal collaterals.

Recent Advances in the Therapeutic and Diagnostic Use of Liposomes and Carbon Nanomaterials in Ischemic Stroke

The complexity of the central nervous system (CNS), its limited self-repairing capacity and the ineffective delivery of most CNS drugs to the brain contribute to the irreversible and progressive nature of many neurological diseases and also the severity of the outcome. Therefore, neurological disorders belong to the group of pathologies with the greatest need of new technologies for diagnostics and therapeutics. In this scenario, nanotechnology has emerged with innovative and promising biomaterials and tools. This review focuses on ischemic stroke, being one of the major causes of death and serious long-term disabilities worldwide, and the recent advances in the study of liposomes and carbon nanomaterials for therapeutic and diagnostic purposes. Ischemic stroke occurs when blood flow to the brain is insufficient to meet metabolic demand, leading to a cascade of physiopathological events in the CNS including local blood brain barrier (BBB) disruption. However, to date, the only treatment approved by the FDA for this pathology is based on the potentially toxic tissue plasminogen activator. The techniques currently available for diagnosis of stroke also lack sensitivity. Liposomes and carbon nanomaterials were selected for comparison in this review, because of their very distinct characteristics and ranges of applications. Liposomes represent a biomimetic system, with composition, structural organization and properties very similar to biological membranes. On the other hand, carbon nanomaterials, which are not naturally encountered in the human body, exhibit new modes of interaction with biological molecules and systems, resulting in unique pharmacological properties. In the last years, several neuroprotective agents have been evaluated under the encapsulated form in liposomes, in experimental models of stroke. Effective drug delivery to the brain and neuroprotection were achieved using stealth liposomes bearing targeting ligands onto their surface for brain endothelial cells and ischemic tissues receptors. Carbon nanomaterials including nanotubes, fullerenes and graphene, started to be investigated and potential applications for therapy, biosensing and imaging have been identified based on their antioxidant action, their intrinsic photoluminescence, their ability to cross the BBB, transitorily decrease the BBB paracellular tightness, carry oligonucleotides and cells and induce cell differentiation. The potential future developments in the field are finally discussed.

Cerebral embolization, silent cerebral infarction and neurocognitive decline after thoracic endovascular aortic repair

Background

Silent cerebral infarction is brain injury detected incidentally on imaging; it can be associated with cognitive decline and future stroke. This study investigated cerebral embolization, silent cerebral infarction and neurocognitive decline following thoracic endovascular aortic repair (TEVAR).

Methods

Patients undergoing elective or emergency TEVAR at Imperial College Healthcare NHS Trust and Guy's and St Thomas' NHS Foundation Trust between January 2012 and April 2015 were recruited. Aortic atheroma graded from 1 (normal) to 5 (mobile atheroma) was evaluated by preoperative CT. Patients underwent intraoperative transcranial Doppler imaging (TCD), preoperative and postoperative cerebral MRI, and neurocognitive assessment.

Results

Fifty-two patients underwent TEVAR. Higher rates of TCD-detected embolization were observed with greater aortic atheroma (median 207 for grade 4–5 versus 100 for grade 1–3; P = 0·042), more proximal landing zones (median 450 for zone 0–1 versus 72 for zone 3–4; P = 0·001), and during stent-graft deployment and contrast injection (P = 0·001). In univariable analysis, left subclavian artery bypass (β coefficient 0·423, s.e. 132·62, P = 0·005), proximal landing zone 0–1 (β coefficient 0·504, s.e. 170·57, P = 0·001) and arch hybrid procedure (β coefficient 0·514, s.e. 182·96, P &lt; 0·001) were predictors of cerebral emboli. Cerebral infarction was detected in 25 of 31 patients (81 per cent) who underwent MRI: 21 (68 per cent) silent and four (13 per cent) clinical strokes. Neurocognitive decline was seen in six of seven domains assessed in 15 patients with silent cerebral infarction, with age a significant predictor of decline.

Conclusion

This study demonstrates a high rate of cerebral embolization and neurocognitive decline affecting patients following TEVAR. Brain injury after TEVAR is more common than previously recognized, with cerebral infarction in more than 80 per cent of patients.

Quick Brain Magnetic Resonance Imaging With Diffusion-Weighted Imaging as a First Imaging Modality in Pediatric Stroke

BACKGROUND

Diagnostic delay hinders management of pediatric arterial ischemic stroke. Quick brain MRI with diffusion-weighted imaging sequences may provide a rapid diagnosis without the ionizing radiation of a computed tomography (CT) scan.

METHODS

This was a single center retrospective chart review of children one month to 18 years old with acute arterial ischemic stroke hospitalized between January 2010 and January 2017. We evaluated sensitivity and the time to diagnostic study based on the first imaging study (CT or quick brain MRI with diffusion-weighted imaging).

RESULTS

Twenty-five patients were included. Eleven patients (44%) were initially assessed with CT, 10 (40%) with quick brain MRI with diffusion-weighted imaging, and four (16%) with a full MRI. Compared with children undergoing CT, children with quick brain MRI with diffusion-weighted imaging as first study were younger (5.8 versus 14.1 years, P < 0.001) and were more likely to be hospitalized at stroke onset (70% versus 18.2%, P = 0.03). Quick brain MRI with diffusion-weighted imaging was more sensitive for ischemia than CT (100% versus 27.3%). The median time from presentation to diagnostic imaging was 4.3 hours, with no differences between CT and quick brain MRI with diffusion-weighted imaging groups, although the quick brain MRI with diffusion-weighted imaging group had a shorter median time from first imaging to diagnostic imaging (P = 0.002). There were no significant missed findings on quick brain MRI with diffusion-weighted imaging.

CONCLUSIONS

Quick brain MRI with diffusion-weighted imaging was more sensitive than CT for detecting ischemia and may be considered as the first study for some children presenting with suspected arterial ischemic stroke.

Diffusion-weighted imaging in identifying breast cancer pathological response to neoadjuvant chemotherapy: A meta-analysis

Background

Diffusion-weighted imaging (DWI) is increasingly used to identify pathological complete responses (pCRs) to neoadjuvant chemotherapy (NAC) in breast cancer. The aim of the present study was to assess the utility of DWI using a pooled analysis.

Materials and Methods

Literature databases were searched prior to July 2017. Fifteen studies with a total of 1181 patients were included. The data were extracted to perform pooled analysis, heterogeneity testing, threshold effect testing, sensitivity analysis, publication bias analysis and subgroup analyses.

Result

The methodological quality was moderate. Remarkable heterogeneity was detected, primarily due to a threshold effect. The pooled weighted values were a sensitivity of 0.88 (95% confidence interval (CI): 0.81, 0.92), a specificity of 0.79 (95% CI: 0.70, 0.86), a positive likelihood ratio of 4.1 (95% CI: 2.9, 5.9), a negative likelihood ratio of 0.16 (95% CI: 0.10, 0.24), and a diagnostic odds ratio of 26 (95% CI: 15, 46). The area under the receiver operator characteristic curve was 0.91 (95% CI: 0.88, 0.93). In the subgroup analysis, the pooled specificity of change in the apparent diffusion coefficient (ADC) subgroup was higher than that in the pre-treatment ADC subgroup (0.80 [95% CI: 0.71, 087] vs. 0.63 [95% CI: 0.52, 0.73], P = 0.027).

Conclusions

DWI may be an accurate and nonradioactive imaging technique for identifying pCRs to NAC in breast cancer. Nonetheless, there are a variety of issues when assessing DWI techniques for estimating breast cancer responses to NAC, and large scale and well-designed clinical trials are needed to assess the technique's diagnostic value.

Meta-analysis of diffusion-weighted imaging for predicting locoregional failure of chemoradiotherapy in patients with head and neck squamous cell carcinoma

The purpose of this study was to evaluate the accuracy of diffusion-weighted imaging (DWI) for predicting locoregional failure of chemoradiotherapy in patients with head and neck squamous cell carcinoma (HNSCC). A comprehensive search was conducted through the EMBASE, PubMed and Cochrane Library databases for relevant publications. Stata software was used to calculate the pooled sensitivity, specificity, likelihood ratios and diagnostic odds ratios, and to construct a summary receiver operating characteristics (sROC) curve for DWI. A total of 9 studies comprising 421 patients were included. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio were 0.82 [95% confidence interval (CI): 0.72-0.88], 0.70 (95% CI: 0.62-0.77), 2.7 (95% CI: 2.1-3.6), 0.26 (95% CI: 0.17-0.41), and 10.48 (95% CI: 5.35-20.53), respectively. The area under the sROC curve was 0.84 (95% CI: 0.81-0.87). Therefore, DWI appears to be a promising imaging modality for predicting local failure of chemoradiotherapy in patients with HNSCC.

Safety of thrombolysis in stroke mimics: an observational cohort study from an urban teaching hospital in Sweden

OBJECTIVES

Acute stroke management has changed dramatically over the recent years, where a timely assessment is driven by the expanding treatment options of acute ischaemic stroke. This increases the risk in treating non-stroke patients (stroke mimics) with a possibly hazardous intravenous thrombolysis treatment (IVT).

SETTING

Patients of the thrombolysis registry of Södersjukhuset AB, a secondary health centre in Stockholm, were retrospectively studied to determine complications and outcome after IVT in strokes and stroke mimics.

PARTICIPANTS

Consecutively, 674 recruited patients from 1 January 2008 to 1 December 2013 were analysed regarding demographics and outcome at 3 months after onset of symptoms.

RESULTS

Ischaemic stroke was confirmed in 625 patients (93%), and 48 patients (7%) were stroke mimics. Patients with strokes were older than stroke mimics 72 (IQR: 64-81) vs 54 years (IQR 40-67), p<0.0001. Antihypertensive and antithrombotic treatment were more common in patients with stroke (p<0.0001 and p=0.006, respectively). National Institute of Health Stroke Scale did not differ at time of presentation. Excellent outcome defined as modified Rankin Scale score 0-1, at 3 months, was less common in stroke than in stroke mimics (50% vs 87.5%, p<0.0001). No stroke mimic had a symptomatic intracerebral haemorrhage. Age of less than 40 years may be a predictor for a patient to be a stroke mimic (OR: 8.7, 95% CI: 3.2 to 24.0, p<0.0001).

CONCLUSIONS

Stroke mimics receiving IVT had a more favourable outcome compared with patients with stroke, and showed no haemorrhagic complications. Age below 40 years may be a predictor for stroke mimics.

Direct comparison of PET/CT and MRI to predict the pathological response to neoadjuvant chemotherapy in breast cancer: a meta-analysis

Both PET/CT and breast MRI are used to assess pathological complete response to neoadjuvant chemotherapy (NAC) in patients with breast cancer. The aim is to compare the utility of PET/CT and breast MRI by using head-to-head comparative studies. Literature databases were searched prior to July 2016. Eleven studies with a total of 527 patients were included. For PET/CT, the pooled SEN was 0.87 (95% confidence interval (CI): 0.71-0.95) and SPE was 0.85 (95% CI: 0.70-0.93). For MRI, the pooled SEN was 0.79 (95% CI: 0.68-0.87) and SPE was 0.82 (95% CI: 0.72-0.89). In the conventional contrast enhanced (CE)-MRI subgroup, PET/CT outperformed conventional CE-MRI with a higher pooled sensitivity (0.88 (95% CI: 0.71, 0.95) vs. 0.74 (95% CI: 0.60, 0.85), P = 0.018). In the early evaluation subgroup, PET/CT was superior to MRI with a notable higher pooled specificity (0.94 (95% CI: 0.78, 0.98) vs. 0.83 (95% CI: 0.81, 0.87), P = 0.015). The diagnostic performance of MRI is similar to that of PET/CT for the assessment of breast cancer response to NAC. However, PET/CT is more sensitive than conventional CE-MRI and more specific if the second imaging scan is performed before 3 cycles of NAC.

The impact of installing an MR scanner in the emergency department for patients presenting with acute stroke-like symptoms

PURPOSE

We examined the impact of an MR scanner in the emergency department (ED) on ED length of stay (LOS), hospital (H) LOS, hospital admission rate, hospitalization costs, and ED re-presentation rate of patients presenting with stroke-like symptoms (SLS). We hypothesized that the ED MR would increase efficiency of patient care.

METHODS

The number of MRIs performed in the ED vs. inpatient setting, EDLOS, HLOS, hospitalization charges, admission rate, discharge diagnoses, and 30-60-day ED re-presentation rates were determined for ED patients with SLS six months before (2011) and after (2012) ED MR installation.

RESULTS

362 and 448 patients with SLS presented to the ED, and 196 and 176 patients were admitted in 2011 and 2012 respectively. In 2011, 36 (18.4%) admitted patients, and, in 2012, 68 (38.6%) had MRIs in the ED, p<0.001. In 2011, 74 (37.8%) admitted patients were diagnosed with ischemic stroke, compared to 92 (52.3%) in 2012, p=0.007. HLOS was longer and charges higher for patients with stroke. No patients returned with a confirmed diagnosis of CVA or TIA within 0-60days after being discharged from the ED with negative MR.

CONCLUSIONS

With the ED MR, more admitted patients 1) got scanned in the ED and 2) were diagnosed with stroke. Because this led to more patients on the stroke service actually suffering from strokes (and not other diagnoses), the overall HLOS and charges of patients presenting with SLS were not reduced by ED MR screening. Discharge after a negative ED MR did not incur risk of TIAs or strokes over the ensuing 60days. Therefore, not only does a dedicated MR scanner in the ED aid in the acute diagnosis of a CVA or other neurologic disorder, but it does so without the risk of under-diagnosing TIAs or evolving strokes in the presence of a negative MRI.

The intracerebral hemorrhage acutely decreasing arterial pressure trial II (ICH ADAPT II) protocol

Background

Aggressively lowering blood pressure (BP) in acute intracerebral hemorrhage (ICH) may improve outcome. Although there is no evidence that BP reduction changes cerebral blood flow, retrospective magnetic resonance imaging (MRI) studies have demonstrated sub-acute ischemic lesions in ICH patients. The primary aim of this study is to assess ischemic lesion development in patients randomized to two different BP treatment strategies. We hypothesize aggressive BP reduction is not associated with ischemic injury after ICH.

Methods

The Intracerebral Hemorrhage Acutely Decreasing Blood Pressure Trial II (ICH ADAPT II) is a phase II multi-centre randomized open-label, blinded-endpoint trial. Acute ICH patients (N = 270) are randomized to a systolic blood pressure (SBP) target of <140 or <180 mmHg. Acute ICH patients within 6 h of onset and two SBP measurements ≥140 mmHg recorded >2 mins apart qualify. SBP is managed with a pre-defined treatment protocol. Patients undergo MRI at 48 h, Days 7 and 30, with clinical assessment at Day 30 and 90. The primary outcome is diffusion weighted imaging (DWI) lesion frequency at 48 h. Secondary outcomes include cumulative DWI lesion rate frequency within 30 days, absolute hematoma growth, prediction of DWI lesion incidence, 30-day mortality rates, day 90 functional outcome, and cognitive status.

Discussion

This trial will assess the impact of hypertensive therapies on physiological markers of ischemic injury. The findings of this study will provide evidence for the link, or lack thereof, between BP reduction and ischemic injury in ICH patients.

Trial registration

This study is registered with clinicaltrials.gov  (NCT02281838, first received October 29, 2014).

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-017-0884-4) contains supplementary material, which is available to authorized users.

Mimics and chameleons in stroke

Ischaemic stroke is a treatable medical emergency. In an era of time-dependent reperfusion techniques, it is crucial that an accurate and prompt diagnosis is made. Approximately 30% of patients admitted to hyperacute stroke units are subsequently found not to have a final diagnosis of acute stroke although some of these patients do have incidental or previously symptomatic cerebrovascular disease. These patients do not benefit from thrombolysis and may require the input of other specialists or treatments. Meanwhile, a proportion of patients with acute stroke have unusual presentations and are sometimes initially admitted to general medical admissions units prior to accessing stroke unit care. It is important that atypical presentations of stroke are recognised so that patients are not denied the benefits of stroke unit care and secondary prevention. This article describes some characteristics of common stroke mimics and chameleons, considers how to avoid diagnostic mistakes and discusses the contributory role of imaging.

Understanding Neurologic Complications Following TAVR

Transcatheter aortic valve replacement is a groundbreaking treatment modality for severe, symptomatic aortic stenosis. Despite the rapid progression in indications to include intermediate-risk patients, the risk of peri-procedural stroke remains, with a higher incidence rate than previously reported. Accurate assessment of peri-procedural stroke rates requires selection of careful and meaningful trial endpoints during evaluation of neuroprotective devices. In this article, we review recommendations and stroke definitions from academic research consortiums along with device trial results.

Noninvasive brain-computer interface enables communication after brainstem stroke

Brain-computer interfaces (BCIs) provide communication that is independent of muscle control, and can be especially important for individuals with severe neuromuscular disease who cannot use standard communication pathways or other assistive technology. It has previously been shown that people with amyotrophic lateral sclerosis (ALS) can successfully use BCI after all other means of independent communication have failed. The BCI literature has asserted that brainstem stroke survivors can also benefit from BCI use. This study used a P300-based event-related potential spelling system. This case study demonstrates that an individual locked-in owing to brainstem stroke was able to use a noninvasive BCI to communicate volitional messages. Over a period of 13 months, the participant was able to successfully operate the system during 40 of 62 recording sessions. He was able to accurately spell words provided by the experimenter and to initiate dialogues with his family. The results broadly suggest that, regardless of the precipitating event, BCI use may be of benefit to those with locked-in syndrome.

Misdiagnosing Dizzy Patients: Common Pitfalls in Clinical Practice

This article highlights 5 pitfalls in the diagnosis of common vestibular disorders: (1) overreliance on dizziness symptom type to drive diagnostic inquiry; (2) underuse and misuse of timing and triggers to categorize patients; (3) underuse, misuse, and misconceptions linked to hallmark eye examination findings; (4) overweighting age, vascular risk factors, and neuroexamination to screen for stroke; and (5) overuse and overreliance on head computed tomography to rule out neurologic causes. This article discusses the evidence base describing each pitfall's frequency and likely causes, and potential alternative strategies that might be used to improve diagnostic accuracy or mitigate harms.

Relationship between the lesion location of acute ischemic stroke and early depressive symptoms in Japanese patients

BACKGROUND

Approximately one-third of stroke survivors suffer from post-stroke depression (PSD) in the acute or chronic stages. The presence of PSD in the acute stage after stroke is reportedly associated with poor patient prognosis; therefore, early recognition and treatment of PSD may alleviate these consequences. The aim of the current study was to examine the relationship between the lesion location and the presence of early depressive symptoms after acute ischemic stroke in Japanese patients.

METHODS

Our study included 421 patients who suffered from acute ischemic stroke. On the day of admission, the lesion location was determined using magnetic resonance imaging (MRI). Stroke severity was measured on the seventh day of hospitalization withat the National Institutes of Health Stroke Scale (NIHSS). On the tenth day of hospitalization, depressive symptoms were measured and functional assessments were performed with the Japan Stroke Scale (Depression Scale) (JSS-D) and functional independence measure (FIM), respectively.

RESULTS

A total of 71 subjects (16.9 %) were diagnosed with depression. According to the multiple logistic regression analysis, the infarcts located at frontal and temporal lobes were found to be a significant independent risk factor of early depressive symptoms in the acute stage of stroke.

CONCLUSIONS

Patients suffering from acute ischemic stroke, particularly in the frontal and temporal lobes, should be carefully assessed to detect and treat early depressive symptoms; such treatment may improve patient outcomes.

Diffusion-weighted MRI in differentiating malignant from benign thyroid nodules: a meta-analysis

OBJECTIVES

To perform a meta-analysis to evaluate the diagnostic efficacy of diffusion-weighted imaging (DWI) in differentiating malignant from benign thyroid nodules.

DESIGN

A meta-analysis.

DATA SOURCES AND STUDY SELECTION

Medical and scientific literature databases were searched for original articles published up to August 2015. Studies were selected if they (1) included diagnostic DWI for differentiating malignant from benign thyroid lesions, (2) included patients who later underwent biopsy and (3) presented sufficient data to enable the construction of contingency tables.

DATA SYNTHESIS

For each study, the true-positive, false-positive, true-negative and false-negative values were extracted or derived, and 2×2 contingency tables were constructed. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) instrument. The heterogeneity test, threshold effect test, subgroup analyses and publication bias analyses were performed.

RESULTS

From the 113 identified search results, 15 studies, representing a total of 765 lesions, were included in the meta-analysis. We detected heterogeneity between studies but found no evidence of publication bias. The methodological quality was moderate. The pooled weighted sensitivity was 0.90 (95% CI 0.85 to 0.93); the specificity was 0.95 (95% CI 0.88 to 0.98); the positive likelihood ratio was 16.49 (95% CI 7.37 to 36.86); the negative likelihood ratio was 0.11 (95% CI 0.08 to 0.16); and the diagnostic OR was 150.73 (95% CI 64.96 to 349.75). The area under the receiver operator characteristic curve was 0.95 (95% CI 0.93 to 0.97).

CONCLUSIONS

Quantitative DWI may be a non-invasive, non-radiative and accurate method of distinguishing malignant from benign thyroid nodules. Nevertheless, large-scale trials are necessary to assess its clinical value and to establish standards regarding b values and cut-off values for DWI-based diagnosis.

Cerebral Perfusion Pressure is Maintained in Acute Intracerebral Hemorrhage: A CT Perfusion Study

BACKGROUND AND PURPOSE

Although blood pressure reduction has been postulated to result in a fall in cerebral perfusion pressure in patients with intracerebral hemorrhage, the latter is rarely measured. We assessed regional cerebral perfusion pressure in patients with intracerebral hemorrhage by using CT perfusion source data.

MATERIALS AND METHODS

Patients with acute primary intracerebral hemorrhage were randomized to target systolic blood pressures of <150 mm Hg (n = 37) or <180 mm Hg (n = 36). Regional maps of cerebral blood flow, cerebral perfusion pressure, and cerebrovascular resistance were generated by using CT perfusion source data, obtained 2 hours after randomization.

RESULTS

Perihematoma cerebral blood flow (38.7 ± 11.9 mL/100 g/min) was reduced relative to contralateral regions (44.1 ± 11.1 mL/100 g/min, P = .001), but cerebral perfusion pressure was not (14.4 ± 4.6 minutes(-1) versus 14.3 ± 4.8 minutes(-1), P = .93). Perihematoma cerebrovascular resistance (0.34 ± 0.11 g/mL) was higher than that in the contralateral region (0.30 ± 0.10 g/mL, P < .001). Ipsilateral and contralateral cerebral perfusion pressure in the external (15.0 ± 4.6 versus 15.6 ± 5.3 minutes(-1), P = .15) and internal (15.0 ± 4.8 versus 15.0 ± 4.8 minutes(-1), P = .90) borderzone regions were all similar. Borderzone cerebral perfusion pressure was similar to mean global cerebral perfusion pressure (14.7 ± 4.7 minutes(-1), P ≥ .29). Perihematoma cerebral perfusion pressure did not differ between blood pressure treatment groups (13.9 ± 5.5 minutes(-1) versus 14.8 ± 3.4 minutes(-1), P = .38) or vary with mean arterial pressure (r = -0.08, [-0.10, 0.05]).

CONCLUSIONS

Perihematoma cerebral perfusion pressure is maintained despite increased cerebrovascular resistance and reduced cerebral blood flow. Aggressive antihypertensive therapy does not affect perihematoma or borderzone cerebral perfusion pressure. Maintenance of cerebral perfusion pressure provides physiologic support for the safety of blood pressure reduction in intracerebral hemorrhage.

Nanotheragnostic applications for ischemic and hemorrhagic strokes: improved delivery for a better prognosis

Stroke is the second leading cause of death worldwide and a major cause of long-term severe disability representing a global health burden and one of the highly researched medical conditions. Nanostructured material synthesis and engineering have been recently developed and have been largely integrated into many fields including medicine. Recent studies have shown that nanoparticles might be a valuable tool in stroke. Different types, shapes, and sizes of nanoparticles have been used for molecular/biomarker profiling and imaging to help in early diagnosis and prevention of stroke and for drug/RNA delivery for improved treatment and neuroprotection. However, these promising applications have limitations, including cytotoxicity, which hindered their adoption into clinical use. Future research is warranted to fully develop and effectively and safely translate nanoparticles for stroke diagnosis and treatment into the clinic. This work will discuss the emerging role of nanotheragnostics in stroke diagnosis and treatment applications.

Current concepts on magnetic resonance imaging (MRI) perfusion-diffusion assessment in acute ischaemic stroke: a review & an update for the clinicians

Recently, several medical societies published joint statements about imaging recommendations for acute stroke and transient ischaemic attack patients. In following with these published guidelines, we considered it appropriate to present a brief, practical and updated review of the most relevant concepts on the MRI assessment of acute stroke. Basic principles of the clinical interpretation of diffusion, perfusion, and MRI angiography (as part of a global MRI protocol) are discussed with accompanying images for each sequence. Brief comments on incidence and differential diagnosis are also included, together with limitations of the techniques and levels of evidence. The purpose of this article is to present knowledge that can be applied in day-to-day clinical practice in specialized stroke units or emergency rooms to attend patients with acute ischaemic stroke or transient ischaemic attack according to international standards.

Multimodal imaging in acute ischemic stroke

OPINION STATEMENT

Recent years have seen the development of novel neuroimaging techniques whose roles in the management of acute stroke are sometimes confusing and controversial. This may be attributable in part to a focus on establishing simplified algorithms and terminology that omit consideration of the basic pathophysiology of cerebral ischemia and, consequently, of the full potential for optimizing patients' care based upon their individual imaging findings. This review begins by discussing cerebral hemodynamic physiology and of the effects of hemodynamic disturbances upon the brain. Particular attention will be paid to the hemodynamic measurements and markers of tissue injury that are provided by common clinical imaging techniques, with the goal of enabling greater confidence and flexibility in understanding the potential uses of these techniques in various clinical roles, which will be discussed in the remainder of the review.