BACKGROUND AND PURPOSE:Mechanical thrombectomy (MTB) is a reference treatment for acute ischemic stroke, with several endovascular strategies currently available. However, no quantitative methods are ...available for the selection of the best endovascular strategy or to predict the difficulty of clot removal. We aimed to investigate the predictive value of an endovascular strategy based on radiomic features extracted from the clot on preinterventional, noncontrast computed tomography to identify patients with first-attempt recanalization with thromboaspiration and to predict the overall number of passages needed with an MTB device for successful recanalization.
METHODS:We performed a study including 2 cohorts of patients admitted to our hospitala retrospective training cohort (n=109) and a prospective validation cohort (n=47). Thrombi were segmented on noncontrast computed tomography, followed by the automatic computation of 1485 thrombus-related radiomic features. After selection of the relevant features, 2 machine learning models were developed on the training cohort to predict (1) first-attempt recanalization with thromboaspiration and (2) the overall number of passages with MTB devices for successful recanalization. The performance of the models was evaluated on the prospective validation cohort.
RESULTS:A small subset of radiomic features (n=9) was predictive of first-attempt recanalization with thromboaspiration (receiver operating characteristic curve–area under the curve, 0.88). The same subset also predicted the overall number of passages required for successful recanalization (explained variance, 0.70; mean squared error, 0.76; Pearson correlation coefficient, 0.73; P<0.05).
CONCLUSIONS:Clot-based radiomics have the ability to predict an MTB strategy for successful recanalization in acute ischemic stroke, thus allowing a potentially better selection of the MTB strategy, as well as patients who are most likely to benefit from the intervention.
•Intermanual transfer is observed in a sequence learning task, independently of the trained hand's performance.•Pre-training connectivity strength between premotor cortex and nodes within visual ...attention and executive control networks correlates with transfer.•Intermanual transfer is associated with functional connectivity changes within the motor network after training.
Intermanual transfer of motor learning is a form of learning generalization that leads to behavioral advantages in various tasks of daily life. It might also be useful for rehabilitation of patients with unilateral motor deficits. Little is known about neural structures and cognitive processes that mediate intermanual transfer. Previous studies have suggested a role for primary motor cortex (M1) and the supplementary motor area (SMA). Here, we investigated the functional neuroanatomy of intermanual transfer with a special emphasis on functional connectivity within the motor network and between motor regions and attentional networks, including the fronto-parietal executive control network and visual attention networks. We designed a finger tapping task, in which young, heathy subjects trained the non-dominant left hand in the MRI scanner. Behaviorally, transfer of sequence learning was observed in most cases, independently of the trained hand's performance. Pre- and post-training functional connectivity patterns of cortical motor seeds were investigated using generalized psychophysiological interaction analyses. Transfer was correlated with the strength of connectivity between the left premotor cortex and structures within the dorsal attention network (superior parietal cortex, left middle temporal gyrus) and executive control network (right prefrontal regions) during pre-training, relative to post-training. Changes in connectivity within the motor network, and more particularly between trained and untrained M1, as well as between the SMA and untrained M1, correlated with transfer after training. Together, these results suggest that the interplay between attentional, executive and motor networks may support processes leading to transfer, whereas, following training, transfer translates into increased connectivity within the motor network.
After a century of false hopes, recent studies have placed the concept of diaschisis at the centre of the understanding of brain function. Originally, the term 'diaschisis' was coined by von Monakow ...in 1914 to describe the neurophysiological changes that occur distant to a focal brain lesion. In the following decades, this concept triggered widespread clinical interest in an attempt to describe symptoms and signs that the lesion could not fully explain. However, the first imaging studies, in the late 1970s, only partially confirmed the clinical significance of diaschisis. Focal cortical areas of diaschisis (i.e. focal diaschisis) contributed to the clinical deficits after subcortical but only rarely after cortical lesions. For this reason, the concept of diaschisis progressively disappeared from the mainstream of research in clinical neurosciences. Recent evidence has unexpectedly revitalized the notion. The development of new imaging techniques allows a better understanding of the complexity of brain organization. It is now possible to reliably investigate a new type of diaschisis defined as the changes of structural and functional connectivity between brain areas distant to the lesion (i.e. connectional diaschisis). As opposed to focal diaschisis, connectional diaschisis, focusing on determined networks, seems to relate more consistently to the clinical findings. This is particularly true after stroke in the motor and attentional networks. Furthermore, normalization of remote connectivity changes in these networks relates to a better recovery. In the future, to investigate the clinical role of diaschisis, a systematic approach has to be considered. First, emerging imaging and electrophysiological techniques should be used to precisely map and selectively model brain lesions in human and animals studies. Second, the concept of diaschisis must be applied to determine the impact of a focal lesion on new representations of the complexity of brain organization. As an example, the evaluation of remote changes in the structure of the connectome has so far mainly been tested by modelization of focal brain lesions. These changes could now be assessed in patients suffering from focal brain lesions (i.e. connectomal diaschisis). Finally, and of major significance, focal and non-focal neurophysiological changes distant to the lesion should be the target of therapeutic strategies. Neuromodulation using transcranial magnetic stimulation is one of the most promising techniques. It is when this last step will be successful that the concept of diaschisis will gain all the clinical respectability that could not be obtained in decades of research.
BackgroundDirect thromboaspiration has been reported as an effective mechanical treatment for acute ischemic stroke. We aimed to determine whether the angle of interaction between the aspiration ...catheter and the clot affects the success of clot removal in ischemic stroke patients with large vessel occlusion in the anterior and posterior circulation.MethodsAll patients treated at our institution by direct thromboaspiration as a firstline technique between January 2016 and December 2017 were enrolled in the study. We retrospectively reviewed baseline and procedural characteristics, the angle of interaction formed between the aspiration catheter and the clot, the modified Thrombolysis in Cerebral Infarction score, and the 3 month modified Rankin Scale score.Results85 patients underwent direct thromboaspiration as the firstline treatment during the study period. 100 direct thromboaspiration passes were performed. An angle of interaction of ≥125.5° significantly influenced the success of clot removal (P<0.001) with good sensitivity and specificity, in particular for occlusion of the middle cerebral and basilar artery. The combination of aspiration with a stent retriever based thrombectomy was a valid rescue treatment in cases of standalone direct thromboaspiration failure.ConclusionsIn our series, an angle of interaction between the aspiration catheter and the clot of ≥125.5° was significantly associated with successful clot removal. The prediction of the angle of interaction on pretreatment imaging may help operators to select the most adequate mechanical thrombectomy technique on a case by case basis.
OBJECTIVES:To analyze the effect of tight glycemic control with the use of intensive insulin therapy on cerebral glucose metabolism in patients with severe brain injury.
DESIGN:Retrospective analysis ...of a prospective observational cohort.
SETTING:University hospital neurologic intensive care unit.
PATIENTS:Twenty patients (median age 59 yrs) monitored with cerebral microdialysis as part of their clinical care.
INTERVENTIONS:Intensive insulin therapy (systemic glucose target4.4–6.7 mmol/L 80–120 mg/dL).
MEASUREMENTS AND MAIN RESULTS:Brain tissue markers of glucose metabolism (cerebral microdialysis glucose and lactate/pyruvate ratio) and systemic glucose were collected hourly. Systemic glucose levels were categorized as within the target “tight” (4.4–6.7 mmol/L 80–120 mg/dL) vs. “intermediate” (6.8–10.0 mmol/L 121–180 mg/dL) range. Brain energy crisis was defined as a cerebral microdialysis glucose <0.7 mmol/L with a lactate/pyruvate ratio >40. We analyzed 2131 cerebral microdialysis samplestight systemic glucose levels were associated with a greater prevalence of low cerebral microdialysis glucose (65% vs. 36%, p < 0.01) and brain energy crisis (25% vs.17%, p < 0.01) than intermediate levels. Using multivariable analysis, and adjusting for intracranial pressure and cerebral perfusion pressure, systemic glucose concentration (adjusted odds ratio 1.23, 95% confidence interval CI 1.10–1.37, for each 1 mmol/L decrease, p < 0.001) and insulin dose (adjusted odds ratio 1.10, 95% CI 1.04–1.17, for each 1 U/hr increase, p = 0.02) independently predicted brain energy crisis. Cerebral microdialysis glucose was lower in nonsurvivors than in survivors (0.46 ± 0.23 vs. 1.04 ± 0.56 mmol/L, p < 0.05). Brain energy crisis was associated with increased mortality at hospital discharge (adjusted odds ratio 7.36, 95% CI 1.37–39.51, p = 0.02).
CONCLUSIONS:In patients with severe brain injury, tight systemic glucose control is associated with reduced cerebral extracellular glucose availability and increased prevalence of brain energy crisis, which in turn correlates with increased mortality. Intensive insulin therapy may impair cerebral glucose metabolism after severe brain injury.
Although prevention of dementia and late-life cognitive decline is a major public health priority, there are currently no generally established prevention strategies or operational models for ...implementing such strategies into practice. This article is a narrative review of available evidence from multidomain dementia prevention trials targeting several risk factors and disease mechanisms simultaneously, in individuals without dementia at baseline. Based on the findings, we formulate recommendations for implementing precision risk reduction strategies into new services called Brain Health Services. A literature search was conducted using medical databases (MEDLINE via PubMed and SCOPUS) to select relevant studies: non-pharmacological multidomain interventions (i.e., combining two or more intervention domains), target population including individuals without dementia, and primary outcomes including cognitive/functional performance changes and/or incident cognitive impairment or dementia. Further literature searches covered the following topics: sub-group analyses assessing potential modifiers for the intervention effect on cognition in the multidomain prevention trials, dementia risk scores used as surrogate outcomes in multidomain prevention trials, dementia risk scores in relation to brain pathology markers, and cardiovascular risk scores in relation to dementia. Multidomain intervention studies conducted so far appear to have mixed results and substantial variability in target populations, format and intensity of interventions, choice of control conditions, and outcome measures. Most trials were conducted in high-income countries. The differences in design between the larger, longer-term trials that met vs. did not meet their primary outcomes suggest that multidomain intervention effectiveness may be dependent on a precision prevention approach, i.e., successfully identifying the at-risk groups who are most likely to benefit. One such successful trial has already developed an operational model for implementing the intervention into practice. Evidence on the efficacy of risk reduction interventions is promising, but not yet conclusive. More long-term multidomain randomized controlled trials are needed to fill the current evidence gaps, especially concerning low- and middle-income countries and integration of dementia prevention with existing cerebrovascular prevention programs. A precision risk reduction approach may be most effective for dementia prevention. Such an approach could be implemented in Brain Health Services.
Stroke in the course of coronavirus disease (COVID-19) has been shown to be associated with more severe respiratory symptoms and higher mortality, but little knowledge in this regard exists on older ...populations. We aimed to investigate the incidence, characteristics, and prognosis of acute stroke in geriatric patients hospitalized with COVID-19.
A monocentric cross-sectional retrospective study of 265 older patients hospitalized with COVID-19 on acute geriatric wards. 11/265 presented a stroke episode during hospitalization. Mortality rates and two-group comparisons (stroke vs non-stroke patients) were calculated and significant variables added in logistic regression models to investigate stroke risk factors.
Combined ischemic and hemorrhagic stroke incidence was 4.15%. 72.7% of events occurred during acute care. Strokes presented with altered state of consciousness and/or delirium in 81.8%, followed by a focal neurological deficit in 45.5%. Ischemic stroke was more frequently unilateral (88.8%) and localized in the middle cerebral artery territory (55.5%). Smoking and a history of previous stroke increased by more than seven (OR 7.44; 95% CI 1.75-31.64; p = 0.007) and five times (OR 5.19; 95% CI 1.50-17.92; p = 0.009), respectively, the risk of stroke. Each additional point in body mass index (BMI) reduced the risk of stroke by 14% (OR 0.86; 95% CI 0.74-0.98; p = 0.03). In-hospital mortality (32.1% vs. 27.3%; p > 0.999) and institutionalization at discharge (36.4% vs. 21.1%; p = 0.258) were similar between patients with and without stroke.
Incident stroke complicating COVID-19 in old patients was associated with active smoking, previous history of stroke, and low BMI. Acute stroke did not influence early mortality or institutionalization rate at discharge.
Dementia has a devastating impact on the quality of life of patients and families and comes with a huge cost to society. Dementia prevention is considered a public health priority by the World Health ...Organization. Delaying the onset of dementia by treating associated risk factors will bring huge individual and societal benefit. Empirical evidence suggests that, in higher-income countries, dementia incidence is decreasing as a result of healthier lifestyles. This observation supports the notion that preventing dementia is possible and that a certain degree of prevention is already in action. Further reduction of dementia incidence through deliberate prevention plans is needed to counteract its growing prevalence due to increasing life expectancy.An increasing number of individuals with normal cognitive performance seek help in the current memory clinics asking an evaluation of their dementia risk, preventive interventions, or interventions to ameliorate their cognitive performance. Consistent evidence suggests that some of these individuals are indeed at increased risk of dementia. This new health demand asks for a shift of target population, from patients with cognitive impairment to worried but cognitively unimpaired individuals. However, current memory clinics do not have the programs and protocols in place to deal with this new population.We envision the development of new services, henceforth called Brain Health Services, devoted to respond to demands from cognitively unimpaired individuals concerned about their risk of dementia. The missions of Brain Health Services will be (i) dementia risk profiling, (ii) dementia risk communication, (iii) dementia risk reduction, and (iv) cognitive enhancement. In this paper, we present the organizational and structural challenges associated with the set-up of Brain Health Services.
A fatal outcome occurs in 2% of patients with Reversible Cerebral Vasoconstriction Syndrome (RCVS). Due to its rarity, guidelines for the management of the most severe forms of RCVS are lacking.
...Here, we describe the case of a 55 year-old woman who died from complications of RCVS and reviewed patients with fatal outcome reported in the literature. In our patient, the first episode of neurological deterioration was preceded by an increase of cerebral blood flow velocities assessed with transcranial Doppler. A fatal evolution could not be prevented despite therapeutic escalation consisting of multiple non-invasive and invasive treatments including cervical sympathetic bloc and continuous arterial infusion of nimodipine at the site of severe vasoconstriction.
This case and the review of literature illustrate the challenges in the management of patients with severe RCVS. We describe here how monitoring of cerebral blood flow might help anticipate clinical worsening at the beginning of the disease and propose novel invasive and non-invasive therapeutic strategies based on monitoring of neurophysiological parameters.
This study aimed to assess if there are sex differences in the functional outcome of intravenous thrombolysis (IVT) among patients with lacunar stroke (LS).
Consecutive patients admitted from 1 ...January 2014 to 31 January 2020 to hospitals participating in the Swiss Stroke Registry presenting with LS and treated with IVT were included. The study population was then divided into two groups based on patient sex, and a multivariable ordinal logistic regression analysis was performed to uncover sex differences in the modified Rankin Scale (mRS) score at 90 days after stroke.
A total of 413 patients with LS were treated with IVT: 177 (42.9%) women and 236 (57.1%) men. Women were older than men (median age 74 years, 25th-75th percentiles 67-84 years versus 70 years, 25th-75th percentiles 60-80 years, value of p 0.001) and, after adjustment for meaningful variables, showed more frequently increased odds of a higher mRS score at 90 days after stroke (adjusted odds ratio 1.49, 95% confidence interval 1.01-2.19, value of p 0.044).
This study showed that female sex increased the odds of a worse functional response to IVT in patients with LS. Future studies should further elucidate the mechanisms underlying such sex differences.
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