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Background: Diffusion-weighted imaging lesion reversal (DWIR) is frequently observed after mechanical thrombectomy for acute ischemic stroke, but little is known about age-related differences and impact on outcome. We aimed to compare, in patients Methods: We retrospectively analyzed data of patients treated for an anterior circulation acute ischemic stroke with large vessel occlusion in 2 French hospitals, who underwent baseline and 24-hour follow-up magnetic resonance imaging, with baseline DWI lesion volume ≥10 cc. The percentage of DWIR (DWIR%), was calculated as follows: DWIR%=(DWIR volume/baseline DWI volume)×100. Data on demographics, medical history, and baseline clinical and radiological characteristics were collected. Results: Among 433 included patients (median age, 68 years), median DWIR% after mechanical thrombectomy was 22% (6–35) in patients ≥80, and 19% (interquartile range, 10–34) in patients P =0.948). In multivariable analyses, successful recanalization after mechanical thrombectomy was associated with higher median DWIR% in both ≥80 ( P =0.004) and P =0.002) patients. In subgroup analyses performed on a minority of subjects, collateral vessels status score (n=87) and white matter hyperintensity volume (n=131) were not associated with DWIR% ( P >0.2). In multivariable analyses, DWIR% was associated with increased rates of favorable 3-month outcomes in both ≥80 ( P =0.003) and P =0.013) patients; the effect of DWIR% on outcome was not influenced by the age group ( P interaction=0.185) Conclusions: DWIR might be an important and nonage-dependent effect of arterial recanalization, as it seems to beneficially impact 3-month outcomes of both younger and older subjects treated with mechanical thrombectomy for acute ischemic stroke and large vessel occlusion.

Background: To further our understanding of the pathophysiology of spontaneous intracerebral hemorrhage (ICH) and related injury, we provided a postmortem neuropathological examination of acute microvascular lesions (microbleeds and microinfarcts) within the perihematomal area. Methods: We included all consecutive cases (2005–2019) from the Lille University Hospital brain bank of ICH patients who died within the first month. Paraffin-embedded tissue sections from the perihematomal area were processed for several stainings and immunolabelings to investigate the presence of acute microbleeds and microinfarcts in the perihematomal area and to characterize surrounding neuronal and systemic inflammatory reaction (macrophages and neutrophils). Results: We included 14 ICH cases (median age, 78 years; 10 females). Acute microbleeds were observed in the perihematomal area in 12/14 patients (86%, ranging from 1 through >10) and microinfarcts in 5/14 (36%, ranging from 1 through 4). Microbleeds were observed whatever the delay from ICH onset to death was, while most cases with acute microinfarcts were observed between day 3 and day 7 (n=3/5). Both lesions were characterized by an abundant accumulation of systemic inflammatory cells and necrotic areas. Conclusions: Acute microbleeds and microinfarcts might contribute to the propagation of secondary brain tissue damages after ICH. Our examinations also question the potential role of massive systemic inflammatory cells recruitment in the genesis of these microvascular injuries.

The mechanisms underlying intracerebral hemorrhage (ICH)-related cognitive impairment (CI) remain unclear. Long-term structural and functional changes were investigated in the brains of healthy male and female Wistar rats after experimental ICH. Following double injection of autologous blood, rats underwent short-term (onset, 3 and 7 days) and long-term (3 and 6 months) radiological assessment and behavioral tests exploring spontaneous locomotion, anxiety-like behavior and working memory, spatial recognition memory and visual recognition memory. Volumetric and metabolic changes in brain areas were examined by 7Tesla-MRI and [18F] FDG-PET, respectively. Brain connectomic disorders and maladaptive processes were seeked through brain metabolic connectivity analysis and atrophy-related network analysis. From an initial hematoma mean volume of 23.35 ± 9.50 mm3, we found early spontaneous locomotor recovery and significant spontaneous blood resorption (≈ 40% of the initial lesion) from days 0 to 7. After 3 and 6 months, ICH rats exhibited CI in several domains as compared to the sham group (working memory: 58.1 ± 1.2 vs. 70.7 ± 1.2%, p < 0.001; spatial recognition memory: 48.7 ± 1.9 vs. 64 ± 1.8%, p < 0.001 and visual recognition memory: 0.14 ± 0.05 vs. 0.33 ± 0.04, p = 0.013, in female only). Rats that experienced ICH had remote and concomitant cerebral atrophy and hypometabolism of ipsilateral striatum, thalamus, limbic system and cortical areas (temporal and parietal lobes). Interestingly, both structural and metabolic deterioration was found in the limbic system connected to the affected site, but remotely from the initial insult. On the other hand, increased activity and functional connectivity occurred in the contralateral hemisphere. These connectomics results showed that both maladaptative and compensation processes coexist in the rat brain following ICH, even at young age and in a disease-free setting. These radiological findings deepen our understanding of ICH-related CI and may serve as biomarkers in the view of future therapeutic intervention.

Optimal antithrombotic management after intracerebral hemorrhage remains one of the central unresolved issues for patients who survive, especially for those patients with atrial fibrillation. Given the observational nature of the studies regarding anticoagulation resumption after intracerebral hemorrhage, there is uncertainty regarding resumption of oral anticoagulation therapy and its timing. There is limited high-quality evidence to guide clinical practice, leading to significant practice variation and uncertainty for patients and providers. Here, we aim to provide the key elements to guide clinicians in their individual decision: whether or not to start or resume anticoagulation in patients with a history of intracerebral hemorrhage.

Background: Cerebral microbleeds (CMBs) have been observed in healthy elderly people undergoing systematic brain magnetic resonance imaging. The potential role of acute triggers on the appearance of CMBs remains unknown. We aimed to describe the incidence of new CMBs after transcatheter aortic valve replacement (TAVR) and to identify clinical and procedural factors associated with new CMBs including hemostatic measures and anticoagulation management. Methods: We evaluated a prospective cohort of patients with symptomatic aortic stenosis referred for TAVR for CMBs (METHYSTROKE [Identification of Epigenetic Risk Factors for Ischemic Complication During the TAVR Procedure in the Elderly]). Standardized neurologic assessment, brain magnetic resonance imaging, and analysis of hemostatic measures including von Willebrand factor were performed before and after TAVR. Numbers and location of microbleeds on preprocedural magnetic resonance imaging and of new microbleeds on postprocedural magnetic resonance imaging were reported by 2 independent neuroradiologists blinded to clinical data. Measures associated with new microbleeds and postprocedural outcome including neurologic functional outcome at 6 months were also examined. Results: A total of 84 patients (47% men, 80.9±5.7 years of age) were included. On preprocedural magnetic resonance imaging, 22 patients (26% [95% CI, 17%–37%]) had at least 1 microbleed. After TAVR, new microbleeds were observed in 19 (23% [95% CI, 14%–33%]) patients. The occurrence of new microbleeds was independent of the presence of microbleeds at baseline and of diffusion-weighted imaging hypersignals. In univariable analysis, a previous history of bleeding ( P =0.01), a higher total dose of heparin ( P =0.02), a prolonged procedure ( P =0.03), absence of protamine reversion ( P =0.04), higher final activated partial thromboplastin time ( P =0.05), lower final von Willebrand factor high-molecular-weight:multimer ratio ( P =0.007), and lower final closure time with adenosine–diphosphate ( P =0.02) were associated with the occurrence of new postprocedural microbleeds. In multivariable analysis, a prolonged procedure (odds ratio, 1.22 [95% CI, 1.03–1.73] for every 5 minutes of fluoroscopy time; P =0.02) and postprocedural acquired von Willebrand factor defect (odds ratio, 1.42 [95% CI, 1.08–1.89] for every lower 0.1 unit of high-molecular-weight:multimer ratio; P =0.004) were independently associated with the occurrence of new postprocedural microbleeds. New CMBs were not associated with changes in neurologic functional outcome or quality of life at 6 months. Conclusions: One out of 4 patients undergoing TAVR has CMBs before the procedure and 1 out of 4 patients develops new CMBs. Procedural or antithrombotic management and persistence of acquired von Willebrand factor defect were associated with the occurrence of new CMBs. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02972008.

Background and Purpose: Despite initial successful recanalization after mechanical thrombectomy (MT), some patients with large artery occlusion (LAO)-related stroke will experience an early reocclusion of the injured vessel which may worsen their prognosis. We aimed to investigate the prevalence, associated factors and prognosis of early reocclusion after successful MT in a large prospective cohort of stroke patients with LAO. Methods: We included patients from the Lille reperfusion registry with LAO-related stroke involving M1 segment, internal carotid artery terminus or tandem ICA-M1 occlusion, with successful recanalization after MT and available 24 h imaging follow-up. Early reocclusion was defined as internal carotid artery terminus or M1 occlusion on 24 h magnetic resonance imaging (MRI) or computed tomography (CT) vascular imaging. Multivariable logistic regression models were used to investigate factors associated with early reocclusion and its impact on outcomes. Results: Between 2015 and 2020, 62 of 1015 included patients experienced an early reocclusion (6.1%). Age (odds ratio (OR) per 15 years decrease: 1.38 (1.05–1.81)) antiplatelet use (OR: 0.41 (0.19–0.89)), several device passes (OR: 2.13 (1.18–3.83)), atherosclerosis cause (OR: 2.38 (1.19–4.78)), and early clinical worsening (OR: 2.45 (1.18–5.07)) were independently associated with early reocclusion. Early reocclusion was independently associated with poor prognosis (OR: 7.15 (3.49–14.65)) and mortality (OR: 2.05 (1.07–3.91)) at 3 months. Conclusion: Six percent of patients with LAO-related stroke and initial successful recanalization experienced early reocclusion. This event is associated with a 7-fold increased risk of poor functional outcome and a 2-fold increased risk of mortality. Further efforts are warranted to refine early detection of patients at risk of reocclusion and to improve their management.

BackgroundSeveral studies have investigated the histopathology of mechanically retrieved thrombi from stroke patients. Thrombi with unusual components constitute about 1–2% of all stroke thrombi in clinical practice. Knowledge about these rare components is limited.ObjectivesTo characterize the histopathology of unusual stroke thrombi from a real-world setting with relation to clinical presentation, patient characteristics and procedural aspects of mechanical thrombectomy.MethodsOne-thousand and eight thrombi retrieved from stroke patients with mechanical thrombectomy at three different hospitals were retrospectively reviewed for unusual histological components. Fifteen thrombi were included in the study for further histopathological analysis. Clinical data and data on procedural aspects were collected.ResultsWe identified six cases with large amounts of extracellular DNA, of which three were calcified. All six cases except one received anticoagulant therapy. We describe two types of calcifications that differ with respect to general calcification morphology, von Kossa staining pattern, macrophage immunophenotype and presence of multinucleated giant cells. Cholesterol-rich (n = 3), adipocyte-like pattern-rich (n = 2), collagen-rich (n = 2) and myxomatous (n = 1) thrombi were also identified and are discussed with regard to pathogenesis and clinical and intervention characteristics. Finally, a thrombus with parts of a vascular wall is described. Suggestions for future studies are made and clinical and technical aspects of the management for these rare but important patients are discussed.ConclusionIn our retrospective multicenter study, we characterized stroke thrombi histopathologically and found subgroups of thrombi defined by presence of rarely seen components. These defined subgroups showed relation to underlying cardiovascular disease, patient characteristics, and mechanical thrombectomy technique. Knowledge about these components may increase our understanding of stroke pathophysiology and influence interventional procedures.

BACKGROUND: Cerebral amyloid angiopathy (CAA) is an age-related small vessel disease, characterised pathologically by progressive deposition of amyloid β in the cerebrovascular wall. The Boston criteria are used worldwide for the in-vivo diagnosis of CAA but have not been updated since 2010, before the emergence of additional MRI markers. We report an international collaborative study aiming to update and externally validate the Boston diagnostic criteria across the full spectrum of clinical CAA presentations.METHODS: In this multicentre, hospital-based, retrospective, MRI and neuropathology diagnostic accuracy study, we did a retrospective analysis of clinical, radiological, and histopathological data available to sites participating in the International CAA Association to formulate updated Boston criteria and establish their diagnostic accuracy across different populations and clinical presentations. Ten North American and European academic medical centres identified patients aged 50 years and older with potential CAA-related clinical presentations (ie, spontaneous intracerebral haemorrhage, cognitive impairment, or transient focal neurological episodes), available brain MRI, and histopathological assessment for CAA diagnosis. MRI scans were centrally rated at Massachusetts General Hospital (Boston, MA, USA) for haemorrhagic and non-haemorrhagic CAA markers, and brain tissue samples were rated by neuropathologists at the contributing sites. We derived the Boston criteria version 2.0 (v2.0) by selecting MRI features to optimise diagnostic specificity and sensitivity in a prespecified derivation cohort (Boston cases 1994-2012, n=159), then externally validated the criteria in a prespecified temporal validation cohort (Boston cases 2012-18, n=59) and a geographical validation cohort (non-Boston cases 2004-18; n=123), comparing accuracy of the new criteria to the currently used modified Boston criteria with histopathological assessment of CAA as the diagnostic standard. We also assessed performance of the v2.0 criteria in patients across all cohorts who had the diagnostic gold standard of brain autopsy.FINDINGS: The study protocol was finalised on Jan 15, 2017, patient identification was completed on Dec 31, 2018, and imaging analyses were completed on Sept 30, 2019. Of 401 potentially eligible patients presenting to Massachusetts General Hospital, 218 were eligible to be included in the analysis; of 160 patient datasets from other centres, 123 were included. Using the derivation cohort, we derived provisional criteria for probable CAA requiring the presence of at least two strictly lobar haemorrhagic lesions (ie, intracerebral haemorrhages, cerebral microbleeds, or foci of cortical superficial siderosis) or at least one strictly lobar haemorrhagic lesion and at least one white matter characteristic (ie, severe visible perivascular spaces in centrum semiovale or white matter hyperintensities in a multispot pattern). The sensitivity and specificity of these criteria were 74·8% (95% CI 65·4-82·7) and 84·6% (71·9-93·1) in the derivation cohort, 92·5% (79·6-98·4) and 89·5% (66·9-98·7) in the temporal validation cohort, 80·2% (70·8-87·6) and 81·5% (61·9-93·7) in the geographical validation cohort, and 74·5% (65·4-82·4) and 95·0% (83·1-99·4) in all patients who had autopsy as the diagnostic standard. The area under the receiver operating characteristic curve (AUC) was 0·797 (0·732-0·861) in the derivation cohort, 0·910 (0·828-0·992) in the temporal validation cohort, 0·808 (0·724-0·893) in the geographical validation cohort, and 0·848 (0·794-0·901) in patients who had autopsy as the diagnostic standard. The v2.0 Boston criteria for probable CAA had superior accuracy to the current Boston criteria (sensitivity 64·5% [54·9-73·4]; specificity 95·0% [83·1-99·4]; AUC 0·798 [0·741-0854]; p=0·0005 for comparison of AUC) across all individuals who had autopsy as the diagnostic standard.INTERPRETATION: The Boston criteria v2.0 incorporate emerging MRI markers of CAA to enhance sensitivity without compromising their specificity in our cohorts of patients aged 50 years and older presenting with spontaneous intracerebral haemorrhage, cognitive impairment, or transient focal neurological episodes. Future studies will be needed to determine generalisability of the v.2.0 criteria across the full range of patients and clinical presentations.FUNDING: US National Institutes of Health (R01 AG26484).

Aim(s) Because of their prothrombotic and neuroinflammatory effects, neutrophils and neutrophil extracellular traps (NETs) represent interesting therapeutic targets for spontaneous intracerebral haemorrhage (sICH). We investigated the presence, spatial and temporal distribution of NETs in a human sICH post-mortem study. Methods From 2005 to 2019, all sICH patients who came to autopsy within the first month after stroke were included and grouped according to the timing of death: 72 hours, 4-7 days, 8-15 days and > 15 days after ICH onset. Paraffin-embedded tissue was extracted from four strategic areas: haematoma, peri-haematomal area, ipsilateral surrounding brain tissue and a control contralateral area. Myeloperoxidase and histone H3 citrulline were immunolabelled to detect neutrophils and NETs, respectively. Results Neutrophils were present in the brains of the 14 cases (4 men, median age: 78 years) and NETs were found in 7/14 cases. Both neutrophils and NETs were detected within the haematoma but also in the surrounding tissue. The appearance of neutrophils and NETs was time-dependent, following a two-wave pattern: during the first 72 hours and between 8-15 days after ICH onset. Qualitative examination showed that neutrophils and NETs were mainly located around dense fibrin fibres within the haematoma. Conclusions These observations provide evidence for NETs infiltration in the brain of patients who die from sICH. NETs might interact with early haemostasis within the haematoma core, and with the surrounding neuroinflammatory response. These findings open research perspectives for NETs in the treatment of sICH injuries.

Cerebral microbleeds (CMBs) are defined as hypointense foci visible on T2*-weighted and susceptible-weighted MRI sequences. CMBs are increasingly recognised with the widespread use of MRI in healthy individuals as well as in the context of cerebrovascular disease or dementia. They can also be encountered in major critical medical conditions such as in patients requiring extracorporeal mechanical oxygenation. The advent of MRI-guided postmortem neuropathological examinations confirmed that, in the context of cerebrovascular disease, the vast majority of CMBs correspond to recent or old microhaemorrhages. Detection of CMBs is highly influenced by MRI parameters, in particular field strength, postprocessing methods used to enhance T2* contrast and three dimensional sequences. Despite recent progress, harmonising imaging parameters across research studies remains necessary to improve cross-study comparisons. CMBs are helpful markers to identify the nature and the severity of the underlying chronic small vessel disease. In daily clinical practice, presence and numbers of CMBs often trigger uncertainty for clinicians especially when antithrombotic treatments and acute reperfusion therapies are discussed. In the present review, we discuss those clinical dilemmas and address the value of CMBs as diagnostic and prognostic markers for future vascular events.

Contains fulltext : 245661.pdf (Publisher’s version ) (Closed access) IMPORTANCE: Thrombosis with thrombocytopenia syndrome (TTS) has been reported after vaccination with the SARS-CoV-2 vaccines ChAdOx1 nCov-19 (Oxford-AstraZeneca) and Ad26.COV2.S (Janssen/Johnson & Johnson). OBJECTIVE: To describe the clinical characteristics and outcome of patients with cerebral venous sinus thrombosis (CVST) after SARS-CoV-2 vaccination with and without TTS. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used data from an international registry of consecutive patients with CVST within 28 days of SARS-CoV-2 vaccination included between March 29 and June 18, 2021, from 81 hospitals in 19 countries. For reference, data from patients with CVST between 2015 and 2018 were derived from an existing international registry. Clinical characteristics and mortality rate were described for adults with (1) CVST in the setting of SARS-CoV-2 vaccine-induced immune thrombotic thrombocytopenia, (2) CVST after SARS-CoV-2 vaccination not fulling criteria for TTS, and (3) CVST unrelated to SARS-CoV-2 vaccination. EXPOSURES: Patients were classified as having TTS if they had new-onset thrombocytopenia without recent exposure to heparin, in accordance with the Brighton Collaboration interim criteria. MAIN OUTCOMES AND MEASURES: Clinical characteristics and mortality rate. RESULTS: Of 116 patients with postvaccination CVST, 78 (67.2%) had TTS, of whom 76 had been vaccinated with ChAdOx1 nCov-19; 38 (32.8%) had no indication of TTS. The control group included 207 patients with CVST before the COVID-19 pandemic. A total of 63 of 78 (81%), 30 of 38 (79%), and 145 of 207 (70.0%) patients, respectively, were female, and the mean (SD) age was 45 (14), 55 (20), and 42 (16) years, respectively. Concomitant thromboembolism occurred in 25 of 70 patients (36%) in the TTS group, 2 of 35 (6%) in the no TTS group, and 10 of 206 (4.9%) in the control group, and in-hospital mortality rates were 47% (36 of 76; 95% CI, 37-58), 5% (2 of 37; 95% CI, 1-18), and 3.9% (8 of 207; 95% CI, 2.0-7.4), respectively. The mortality rate was 61% (14 of 23) among patients in the TTS group diagnosed before the condition garnered attention in the scientific community and 42% (22 of 53) among patients diagnosed later. CONCLUSIONS AND RELEVANCE: In this cohort study of patients with CVST, a distinct clinical profile and high mortality rate was observed in patients meeting criteria for TTS after SARS-CoV-2 vaccination.

International audience; The purpose of this study was to characterize cognitive impairments and behavioral disorders in a sample of patients with chronic kidney disease (CKD). A total of 52 patients with CKD were prospectively recruited over a 344-day period. Cognitive functions (memory, action speed, executive function, and language) and behavioral characteristics were assessed with a standardized comprehensive battery. The patients' performances were interpreted with a validated method on the basis of normative data from 1,003 healthy control subjects. Brain MRI and biological data were collected. Multivariable linear regression models and bootstrap analyses were used to identify risk factors for cognitive impairment. Cognitive impairment was observed in 32.5% (95% confidence interval: 17%-48%) of the 40 included patients with full data sets. Action speed and executive functions were the most frequently impaired domains. Dysexecutive behavioral disorders were observed in 27% of patients, and depression was observed in 32.5%. Cognitive impairment was independently associated with stroke volume, high serum parathyroid hormone and uric acid levels, and low serum glucose levels (adjusted R-2 = 0.54, p

International audience; Neuroinflammation and iron accumulation are hallmarks of a variety of adult neurodegenerative diseases. In Sanfilippo syndrome (mucopolysaccharidosis type III, MPSIII, a pediatric neurodegenerative disease that shares some features with adult neurodegenerative diseases), the progressive accumulation of heparan sulfate oligosaccharides (HSOs) induces microglia and astrocytes to produce pro-inflammatory cytokines leading to severe neuroinflammation. The objectives of the present study were (1) to measure the local iron concentration and to assess iron metabolism in the brain of a MPSIIIB murine model and (2) to identify the brain cells involved in this accumulation. We found that iron accumulation in MPSIIIB mice primarily affected the cerebral cortex where hepcidin levels were higher than in wild-type mice, and increased with aging. This increase was correlated with low expression of ferroportin 1 (FPN1), and thus brain iron retention. Moreover, we showed in vitro that HSOs are directly responsible for the production of hepcidin and the relative decrease in FPN1 expression when added to cultures of microglia and, to a lesser extent, to cultures of astrocytes. In contrast, no significant differences were observed in neurons. Hepcidin induction results from activation of the TLR4 pathway and STAT3 signaling, and leads to iron retention within microglia. Our results show that microglia have a key role in cerebral hepcidin overexpression and thus in the brain iron accumulation observed in the MPSIIIB model.

Sporadic cerebral amyloid angiopathy (CAA) is a small vessel disease caused by vascular deposits of Aß-amyloid peptides in the walls of cortical and leptomeningeal vessels. Advancing age is the strongest known clinical risk factor for developing CAA. This devastating disease occurs frequently in elderly people, and is a frequent cause of symptomatic lobar intracerebral hemorrhage (ICH), cognitive impairment and transient focal neurological episodes. Typical cerebral MRI findings include lobar intracerebral hemorrhages and neuroimaging biomarkers of CAA (lobar cerebral microbleeds, cortical superficial siderosis, white matter hyperintensities, dilated perivascular spaces and microinfarcts). In the absence of direct neuropathological examination, the most commonly used criteria for CAA diagnosis are the modified Boston criteria based on clinical and MRI data. To date, no specific treatment is available to prevent bleeding or cognitive decline. Thus, management is mainly based on strict blood pressure control. Anticoagulation should usually be avoided in patients with a diagnosis of CAA and symptomatic lobar ICH. The risk/benefit ratio evaluation at individual level of antiplatelet agents is also required.

Objectives The ability of voxel-based lesion-symptom mapping (VLSM) to define the functional anatomy of the human brain has not been fully assessed. With a view to assessing VLSM's validity, the present study analyzed the technique's ability to determine the known clinical-anatomic correlates of hemiparesis in stroke patients. Design Lesions (damaged in at least 5 patients) associated with transformed limb motor score (after adjustment on lesion volume) at 6 months were examined in 272 patients using VLSM. The value of additional multivariable linear, logistic and Bayesian analyses was examined. Results We first checked that motor hemiparesis was fully accounted for by corticospinal tract (CST) lesions (sensitivity = 100%; p = 0.0001). Conventional VLSM analysis flagged up 2 regions corresponding to the CST, but also 8 regions located outside the CST. All 10 brain regions achieving statistical significance in the VLSM analysis were submitted to 3 additional analyses. The backward linear regression analysis selected 5 regions, one only corresponding to the CST (R2: 0.03, p = 0.0008). The logistic regression analysis selected correctly the CST (OR: 2.39, 95%CI: 1.44–3.96; 0.001). The Bayesian network analysis selected regions including the CST (in 92% of 3000 bootstrap replications) and identified the source of multicollinearity. These lesions evaluated by structural equation modeling resulted in an excellent fit (p-value = 0.228, chi/df = 1.19, RMSEA = 0.032, CFI = 0.999). Analyses of confusion factors showed that conventional VLSM analyses were strongly influenced by lesion frequency (R2 = 0.377; p = 0.0001) and multicollinearity. Conclusions Conventional VLSM analyses are sensitive but weakened by a type I error due to the combined effects of multicollinearity and lesion frequency. We demonstrate that the addition of a Bayesian network analysis, and to a lesser extent of logistic regression, controlled for this type I error and constituted a reliable means of defining the functional anatomy of the motor system in stroke patients.

Background and Purpose- We aimed to define the neuroimaging determinants of poststroke cognitive performance and their relative contributions among a spectrum of magnetic resonance imaging markers, including lesion burden and strategic locations. Methods- We prospectively included patients with stroke from the GRECogVASC study (Groupe de Réflexion pour l'Évaluation Cognitive Vasculaire) who underwent 3-T magnetic resonance imaging and a comprehensive standardized battery of neuropsychological tests 6 months after the index event. An optimized global cognitive score and neuroimaging markers, including stroke characteristics, cerebral atrophy markers, and small vessel diseases markers, were assessed. Location of strategic strokes was determined using a specifically designed method taking into account stroke size and cerebral atrophy. A stepwise multivariable linear regression model was used to identify magnetic resonance imaging determinants of cognitive performance. Results- Data were available for 356 patients (mean age: 63.67±10.6 years; 326 [91.6%] of the patients had experienced an ischemic stroke). Six months poststroke, 50.8% of patients presented with a neurocognitive disorder. Strategic strokes (right corticospinal tract, left antero-middle thalamus, left arcuate fasciculus, left middle frontal gyrus, and left postero-inferior cerebellum; R

Background It is not clear whether cognitive adverse events can occur after subthalamic nuclei deep brain stimulation in Parkinson disease, and the putative mechanisms are poorly understood. Case Description We report on a rare case of a 68-year-old woman with Parkinson disease but no previous cognitive impairment. The day after deep brain stimulation of the subthalamic nuclei, the woman presented with new-onset dementia and acute, severe, persistent, global cognitive decline, prompting a diagnosis of Alzheimer disease. Conclusions In patients seen in routine clinical practice, the simultaneous presence of several neurodegenerative diseases might not be uncommon. The assessment of mild cognitive impairment with a standardized method is highly recommended, a systematic 3-dimensional volumetric analysis of hippocampal structures should be part of the pre−deep brain stimulation evaluation, and cerebrospinal fluid biomarkers should be screened for if at least 1 of the 2 previously mentioned aspects is abnormal.

Background and Purpose— Cerebral microbleeds are associated with an increased risk of intracerebral hemorrhage. Recent data suggest that microbleeds may also predict the risk of incident ischemic stroke. However, these results were observed in elderly individuals undertaking various medications and for whom causes of microbleeds and ischemic stroke may differ. We aimed to test the relationship between the presence of microbleeds and incident stroke in CADASIL (Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy)—a severe monogenic small vessel disease known to be responsible for both highly prevalent microbleeds and a high incidence of ischemic stroke in young patients. Methods— We assessed microbleeds on baseline MRI in all 378 patients from the Paris–Munich cohort study. Incident ischemic strokes were recorded during 54 months. Survival analyses were used to test the relationship between microbleeds and incident ischemic stroke. Results— Three hundred sixty-nine patients (mean age, 51.4±11.4 years) were followed-up during a median time of 39 months (interquartile range, 19 months). The risk of incident ischemic stroke was higher in patients with microbleeds than in patients without (35.8% versus 19.6%, hazard ratio, 1.87; 95% confidence interval, 1.16–3.01; P =0.009). These results persisted after adjustment for history of ischemic stroke, age, sex, vascular risk factors, and antiplatelet agents use (hazard ratio, 1.89; 95% confidence interval, 1.10–3.26; P =0.02). Conclusions— The presence of microbleeds is an independent risk marker of incident ischemic stroke in CADASIL, emphasizing the need to carefully interpret MRI data.

Cerebrovascular pathologies expose patients to both ischemic and hemorrhagic risks. Given the progressive aging of populations, more and more patients will experience both types of events during their lifetime. The generalization of brain magnetic resonance imaging as a first-line imaging modality for evaluating patients with cerebrovascular diseases has led to the need to manage new types of imaging information about the cerebral tissue, such as the presence, location, and number of cerebral microhemorrhages (CMs). Originally, CMs were thought to be merely spatially localized distortions of the image, mostly secondary to foci of iron deposition within the brain parenchyma. During the past 20 years, however, innumerable research studies have demonstrated that these small foci of signal loss, presumably related to a circumscribed rupture of small vessels, may be used to better estimate the balance between hemorrhagic and ischemic risks. We are now entering the era of personalized medicine, in which treatment decisions are adjusted for each patient according to various genetic, biological, or imaging data. Therefore, integrating CMs into patient management at the individual level will be crucial in the future. This review aims to deliver some clues to interpret the impact of CMs on our clinical decisions.