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Clinical and experimental studies have been shown,that after the combined craniocerebral injury, physiological mechanisms are damaged We maintain perfusion pressure. Partially or completely disruptedShares Autoregulating the brain blood flow. In these conditions after the craniocerebral injury, the brain is not able to respond to the systemic violator Wear homeostasis. As a result, various secondary damage ariseIn the brain tissue is predominantly corridor character thatWe are curved in 80-90% of the dead patients. Is currently among the systemsviolations of homeostasis, most often as secondary damaging factors of the headthe brain. The following: hypotension, hypoxemia, sodium exchange and osmotoostomy, hypocapnia and hyperDrip, hyperthermia, extra-causal inflammatory complications, etc. [1,2,3,4,10,11]. [ABSTRACT FROM AUTHOR]

Aim: How the cerebral metabolic rates of oxygen and glucose utilization (CMRO2 and CMRGlc, respectively) are affected by alterations in arterial PCO2 (PaCO2) is equivocal and therefore was the primary question of this study. Methods: This retrospective analysis involved pooled data from four separate studies, involving 41 healthy adults (35 males/6 females). Participants completed stepwise steady‐state alterations in PaCO2 ranging between 30 and 60 mmHg. The CMRO2 and CMRGlc were assessed via the Fick approach (CBF × arterial‐internal jugular venous difference of oxygen or glucose content, respectively) utilizing duplex ultrasound of the internal carotid artery and vertebral artery to calculate cerebral blood flow (CBF). Results: The CMRO2 was altered by 0.5 mL × min−1 (95% CI: −0.6 to −0.3) per mmHg change in PaCO2 (p < 0.001) which corresponded to a 9.8% (95% CI: −13.2 to −6.5) change in CMRO2 with a 9 mmHg change in PaCO2 (inclusive of hypo‐ and hypercapnia). The CMRGlc was reduced by 7.7% (95% CI: −15.4 to −0.08, p = 0.045; i.e., reduction in net glucose uptake) and the oxidative glucose index (ratio of oxygen to glucose uptake) was reduced by 5.6% (95% CI: −11.2 to 0.06, p = 0.049) with a + 9 mmHg increase in PaCO2. Conclusion: Collectively, the CMRO2 is altered by approximately 1% per mmHg change in PaCO2. Further, glucose is incompletely oxidized during hypercapnia, indicating reductions in CMRO2 are either met by compensatory increases in nonoxidative glucose metabolism or explained by a reduction in total energy production. [ABSTRACT FROM AUTHOR]

Intracranial pressure monitoring enables the detection and treatment of intracranial hypertension, a potentially lethal insult after traumatic brain injury. Despite its widespread use, robust evidence supporting intracranial pressure monitoring and treatment remains sparse. International studies have shown large variations between centres regarding the indications for intracranial pressure monitoring and treatment of intracranial hypertension. Experts have reviewed these two aspects and, by consensus, provided practical approaches for monitoring and treatment. Advances have occurred in methods for non-invasive estimation of intracranial pressure although, for now, a reliable way to non-invasively and continuously measure intracranial pressure remains aspirational. Analysis of the intracranial pressure signal can provide information on brain compliance (ie, the ability of the cranium to tolerate volume changes) and on cerebral autoregulation (ie, the ability of cerebral blood vessels to react to changes in blood pressure). The information derived from the intracranial pressure signal might allow for more individualised patient management. Machine learning and artificial intelligence approaches are being increasingly applied to intracranial pressure monitoring, but many obstacles need to be overcome before their use in clinical practice could be attempted. Robust clinical trials are needed to support indications for intracranial pressure monitoring and treatment. Progress in non-invasive assessment of intracranial pressure and in signal analysis (for targeted treatment) will also be crucial. [ABSTRACT FROM AUTHOR]

Neurovascular coupling (NVC) is the tight relationship between changes in cerebral blood flow and neural activation. NVC can be evaluated non-invasively using transcranial Doppler ultrasound (TCD)-measured changes in brain activation (cerebral blood velocity [CBv]) using different cognitive tasks and stimuli. This study used a novel approach to analyzing CBv changes occurring in response to 20 tasks from the Addenbrooke's Cognitive Examination III in 40 healthy individuals. The novel approach compared various information entropy families (permutation, Tsallis, and Rényi entropy) and statistical complexity measures based on disequilibrium. Using this approach, we found the majority of the attention, visuospatial, and memory tasks from the Addenbrooke's Cognitive Examination III that showed lower statistical complexity values when compared with the resting state. On the entropy-complexity (HC) plane, a receiver operating characteristic curve was used to distinguish between baseline and cognitive tasks using the area under the curve. Best area under the curve values were 0.91 ± 0.04, p =.001, to distinguish between resting and cognitively active states. Our findings show that brain hemodynamic signals captured with TCD can be used to distinguish between resting state (baseline) and cognitive effort (stimulation paradigms) using entropy and statistical complexity as an alternative method to traditional techniques such as coherent averaging of CBv signals. Further work should directly compare these analysis methods to identify the optimal method for analyzing TCD-measured changes in NVC. [ABSTRACT FROM AUTHOR]

Orthostatic hypotension (OH) is a form of orthostatic intolerance (OI) and a key physiological indicator of autonomic dysfunction that is associated with an increased risk of major cerebrocardiovascular events. Symptoms of cerebral hypoperfusion have been reported in patients with OH, which worsens symptoms and increases the risk of syncope. Since pharmacological interventions increase blood pressure (BP) independent of posture and do not restore normal baroreflex control, nonpharmacological treatments are considered the foundation of OH management. While reductions in cerebral blood flow velocity (CBFv) during orthostatic stress are associated with a decrease in end-tidal CO2 (EtCO2) and hypocapnia in patients with OI, their contribution to the severity of OH is not well understood. These measures have been physiological targets in a wide variety of biofeedback interventions. This study explored the relationship between cardiovascular autonomic control, EtCO2 and cerebral hypoperfusion in patients (N = 72) referred for OI. Patients with systolic OH were more likely to be male, older, demonstrate reduced adrenal and vagal baroreflex sensitivity, and reduced cardiovagal control during head-up tilt (HUT) than patients without systolic OH. Greater reduction in CBFv during HUT was associated with a larger reduction in ETCO2 and systolic BP during HUT. While deficits in cardiovascular autonomic control played a more important role in systolic OH, reduced EtCO2 was a major contributor to orthostatic cerebral hypoperfusion. These findings suggest that biofeedback treatments targeting both the autonomic nervous system and EtCO2 should be part of nonpharmacological interventions complementing the standard of care in OH patients with symptoms of cerebral hypoperfusion. [ABSTRACT FROM AUTHOR]

Summary: Background: Noradrenaline is a standard treatment for hypotension in acute care. The precise effects of noradrenaline on cerebral blood flow in health and disease remain unclear. Methods: We systematically reviewed and synthesised data from studies examining changes in cerebral blood flow in healthy participants and patients with traumatic brain injury and critical illness. Results: Twenty‐eight eligible studies were included. In healthy subjects and patients without critical illness or traumatic brain injury, noradrenaline did not significantly change cerebral blood flow velocity (‐1.7%, 95%CI ‐4.7–1.3%) despite a 24.1% (95%CI 19.4–28.7%) increase in mean arterial pressure. In patients with traumatic brain injury, noradrenaline significantly increased cerebral blood flow velocity (21.5%, 95%CI 11.0–32.0%), along with a 33.8% (95%CI 14.7–52.9%) increase in mean arterial pressure. In patients who were critically ill, noradrenaline significantly increased cerebral blood flow velocity (20.0%, 95%CI 9.7–30.3%), along with a 32.4% (95%CI 25.0–39.9%) increase in mean arterial pressure. Our analyses suggest intact cerebral autoregulation in healthy subjects and patients without critical illness or traumatic brain injury., and impaired cerebral autoregulation in patients with traumatic brain injury and who were critically ill. The extent of mean arterial pressure changes and the pre‐treatment blood pressure levels may affect the magnitude of cerebral blood flow changes. Studies assessing cerebral blood flow using non‐transcranial Doppler methods were inadequate and heterogeneous in enabling meaningful meta‐analysis. Conclusions: Noradrenaline significantly increases cerebral blood flow in humans with impaired, not intact, cerebral autoregulation, with the extent of changes related to the severity of functional impairment, the extent of mean arterial pressure changes and pre‐treatment blood pressure levels. [ABSTRACT FROM AUTHOR]

Cerebrovascular autoregulation is defined as the capacity of cerebral blood vessels to maintain stable cerebral blood flow despite changing blood pressure. It is assessed using the pressure reactivity index (the correlation coefficient between mean arterial blood pressure and intracranial pressure). The objective of this scoping review is to describe the existing evidence concerning the association of EEG and cerebrovascular autoregulation in order to identify key concepts and detect gaps in the current knowledge. Embase, MEDLINE, SCOPUS, and Web of Science were searched considering articles between their inception up to September 2023. Inclusion criteria were human (paediatric and adult) and animal studies describing correlations between continuous EEG and cerebrovascular autoregulation assessments. Ten studies describing 481 human subjects (67% adult, 59% critically ill) were identified. Seven studies assessed qualitative (e.g. seizures, epileptiform potentials) and five evaluated quantitative (e.g. bispectral index, alpha-delta ratio) EEG metrics. Cerebrovascular autoregulation was evaluated based on intracranial pressure, transcranial Doppler, or near infrared spectroscopy. Specific combinations of cerebrovascular autoregulation and EEG metrics were evaluated by a maximum of two studies. Seizures, highly malignant patterns or burst suppression, alpha peak frequency, and bispectral index were associated with cerebrovascular autoregulation. The other metrics showed either no or inconsistent associations. There is a paucity of studies evaluating the link between EEG and cerebrovascular autoregulation. The studies identified included a variety of EEG and cerebrovascular autoregulation acquisition methods, age groups, and diseases allowing for few overarching conclusions. However, the preliminary evidence for the presence of an association between EEG metrics and cerebrovascular autoregulation prompts further in-depth investigations. [ABSTRACT FROM AUTHOR]

A single bout of exercise as well as exposure to a hypercapnic environment increases cerebral blood flow (CBF) and is an adaptation linked to a post-intervention executive function (EF) benefit. In the present investigation we sought to determine whether a transient reduction in CBF impairs EF. Accordingly, we employed 10-min -30 mmHg and -50 mmHg lower-body negative pressure (LBNP) interventions as well as a non-LBNP control condition. LBNP was employed because it sequesters blood in the lower legs and safely and reliably decreases CBF. Transcranial Doppler ultrasound was used to measure middle cerebral artery velocity (MCAv) to estimate CBF prior to and during LBNP conditions. As well, assessments of the inhibitory control component of EF (i.e., antipointing) were completed prior to (pre-) and immediately after (i.e., post-) each condition. Antipointing requires that an individual reach mirror-symmetrical to an exogenously presented target and is a task providing the resolution to detect subtle EF changes. Results showed that LBNP produced a 14% reduction in MCAv; however, null hypothesis, equivalence and Bayesian contrasts indicated that antipointing metrics did not vary from pre- to post-intervention, and LBNP-based changes in MCAv magnitude were not reliably correlated with antipointing planning times. Hence, a 10-min reduction in CBF did not impact the efficiency or effectiveness of an inhibitory control measure of EF. [ABSTRACT FROM AUTHOR]

To analyze the correlation of carotid stenosis severity, the Plaque Reporting and Data System (RADS) score, arterial transit artifacts (ATAs), and cerebral blood flow (CBF) with clinical cerebral ischemic symptoms in patients with carotid artery stenosis (CAS). Sixty-one patients with unilateral internal carotid artery stenosis or occlusion (≥50% stenosis) diagnosed by ultrasound, Computed Tomography(CT) angiography, or Magnetic Resonance(MR) angiography in Yichang City Central People's Hospital from January 2022 to February 2024 were retrospectively enrolled and divided into two groups according to the presence or absence of symptoms. Both groups underwent MR plaque imaging and arterial spin labeling (ASL)-based 3.0 T MRI to compare the differences in stenosis degree, Plaque-RADS score, ATA grade, and CBF between the two groups. Binary regression analysis was used to identify the parameters with statistically significant differences between the two groups and to evaluate their diagnostic efficacy using the area under the workup curve of the subjects. The Plaque-RADS score, ATA grade, and CBF differences in the anterior cerebral artery(ACA)blood supply region were correlated with symptoms, and the areas under the ROC curves for the CBF differences in the ACA blood supply region, Plaque-RADS score, ATA grade and a joint model that combines all three to predict symptoms in CAS patients were 0.672, 0.796, 0.788 and 0.919, respectively. CBF, Plaque-RADS and ATAs were identified as independent risk factors for symptoms in patients with CAS and have a certain predictive value for symptoms, and the combined predictive value is greater, potentially providing a more effective imaging modality for clinical treatment and evaluation. • Arterial Transit Artifacts were found to be associated with cerebral ischemia symptoms. • The combination of Plaque-RADS and Arterial Transit Artifacts in predicting symptoms has a higher predictive value. • The PLD used for ASL scanning in this study was 2.0 s, further confirming the broad applicability of our results. [ABSTRACT FROM AUTHOR]

This systematic review aims to identify the diagnostic accuracy of posterior circulation stroke (PCS) by paramedics and the causes and duration of delay in its recognition. A systematic search using CINAHL Plus, MEDLINE, Scopus, and PubMed was performed. All databases were searched up to May 25, 2022. Studies were included where patients were adults, assessed by paramedics, and PCS was the primary diagnosis. Bias was assessed using the Newcastle-Ottawa Scale and the Effective Practice and Organization of Care tool. Results have been described by proportions, and both sensitivity calculations and subgroup analysis were performed utilizing MedCalc. A total of 797 titles/abstracts and a subsequent 87 full texts were screened, of which 15 were included. There were 5395 patients who were assessed by paramedics and had a confirmed diagnosis of PCS. Among five studies containing both true positive and false negative data, there were 98 (45.8%) true positives. PCS patients lost an average of 27 min (p < 0.001) compared to anterior stroke patients in the prehospital setting. One study revealed that educational intervention, including implementing the finger-to-nose test, increased the sensitivity for diagnosis from 45.8 to 74.1% (p = 0.039) and decreased the time from door to computed tomography from 62 to 41 min (p = 0.037). There is a substantial lack of evidence regarding the diagnosis of PCS by paramedics. Despite the low quality of evidence available, overall, the sensitivity for paramedic PCS diagnosis appears to be poor. Further investigation is required into paramedics' diagnosis of PCS and the use of educational interventions. Prospective Register of Systematic Reviews Registration Number: CRD42022324675. [ABSTRACT FROM AUTHOR]

Background: Cerebrovascular reactivity (CVR) is a measure of the change in cerebral blood flow (CBF) in response to a vasoactive challenge. It is a useful indicator of the brain's vascular health. Purpose: To evaluate the factors that influence successful and unsuccessful CVR examinations using precise arterial and end‐tidal partial pressure of CO2 control during blood oxygen level–dependent (BOLD) MRI. Study Type: Retrospective. Subjects: Patients that underwent a CVR between October 2005 and May 2021 were studied (total of 1162 CVR examinations). The mean (±SD) age was 46.1 (±18.8) years, and 352 patients (43%) were female. Field Strength/Sequence: 3 T; T1‐weighted images, T2*‐weighed two‐dimensional gradient‐echo sequence with standard echo‐planar readout. Assessment: Measurements were obtained following precise hypercapnic stimuli using BOLD MRI as a surrogate of CBF. Successful CVR examinations were defined as those where: 1) patients were able to complete CVR testing, and 2) a clinically useful CVR map was generated. Unsuccessful examinations were defined as those where patients were not able to complete the CVR examination or the CVR maps were judged to be unreliable due to, for example, excessive head motion, and poor PETCO2 targeting. Statistical Analysis: Successful and unsuccessful CVR examinations between hypercapnic stimuli, and between different patterns of stimulus were compared with Chi‐Square tests. Interobserver variability was determined by using the intraclass correlation coefficient (P < 0.05 is significant). Results: In total 1115 CVR tests in 662 patients were included in the final analysis. The success rate of generating CVR maps was 90.8% (1012 of 1115). Among the different hypercapnic stimuli, those containing a step plus a ramp protocol was the most successful (95.18%). Among the unsuccessful examinations (9.23%), most were patient related (89.3%), the most common of which was difficulty breathing. Data Conclusion: CO2‐BOLD MRI CVR studies are well tolerated with a high success rate. Evidence Level: 4 Technical Efficacy: Stage 3 [ABSTRACT FROM AUTHOR]

Copyright of Boletín Latinoamericano y del Caribe de Plantas Medicinales y Aromáticas is the property of Universidad de Santiago de Chile and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Latinoamericana de Hipertension is the property of Revista Latinoamericana de Hipertension and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Latinoamericana de Hipertension is the property of Revista Latinoamericana de Hipertension and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Latinoamericana de Hipertension is the property of Revista Latinoamericana de Hipertension and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: MRI using 3D stack‐of‐spirals (SoS) readout on a high‐performance gradient system is subject to strong second‐order, spatially varying concomitant fields, which can lead to signal dropout and blurring artifacts that become more significant at locations farther from the gradient isocenter. A method for compensating for second‐order concomitant fields in 3D axial SoS image reconstruction is described. Methods: We retrospectively correct for second‐order concomitant field–induced phase error in the 3D SoS data by slice‐dependent k‐space phase compensation based on the nominal spiral readout trajectories. The effectiveness of the method was demonstrated in phantom and healthy volunteer scans in which 3D pseudo‐continuous arterial spin labeling imaging was performed with SoS fast spin‐echo readout at 3 T. Results: Substantial reduction in blurring was observed with the proposed method. In phantom scans, blurring was reduced by about 53% at 98 mm from the gradient isocenter. In the in vivo 3D pseudo‐continuous arterial spin labeling scans, differences of up to 10% were observed at 78 mm from the isocenter, especially around the white‐matter and gray‐matter interfaces, between the corrected and uncorrected proton density images, perfusion‐weighted images, and cerebral blood flow maps. Conclusions: The described retrospective correction method provides a means to correct erroneous phase accruals due to second‐order concomitant fields in 3D axial stack‐of‐spirals imaging. [ABSTRACT FROM AUTHOR]

In recent years, the effects of migration on economic outcomes have gained significant attention among researchers and policymakers. In the African context, the complex interplay between migration and economic outcomes is of particular importance, as many countries face unique challenges, such as limited resources, ongoing conflicts, and uneven development. This paper explores the impact of immigration, international migrant cash transfers, and emigration on total factor productivity in Africa, and its implications for public policy. We used the World Development Indicators, the Pen World Table from 2000 to 2020, and instrumental variable estimation in an endogenous growth model. The findings indicate that emigrant human capital and remittances have a negative impact on total factor productivity, whereas immigrant human capital positively affects it. These results highlight the importance of well-defined public migration policies that promote brain circulation, attract skilled immigrants, enhance domestic human capital development, and foster regional co-operation. [ABSTRACT FROM AUTHOR]

Studying brain‐wide hemodynamic responses to different stimuli at high spatiotemporal resolutions can help gain new insights into the mechanisms of neuro‐ diseases and ‐disorders. Nonetheless, this task is challenging, primarily due to the complexity of neurovascular coupling, which encompasses interdependent hemodynamic parameters including cerebral blood volume (CBV), cerebral blood flow (CBF), and cerebral oxygen saturation (SO2). The current brain imaging technologies exhibit inherent limitations in resolution, sensitivity, and imaging depth, restricting their capacity to comprehensively capture the intricacies of cerebral functions. To address this, a multimodal functional ultrasound and photoacoustic (fUSPA) imaging platform is reported, which integrates ultrafast ultrasound and multispectral photoacoustic imaging methods in a compact head‐mountable device, to quantitatively map individual dynamics of CBV, CBF, and SO2 as well as contrast agent enhanced brain imaging at high spatiotemporal resolutions. Following systematic characterization, the fUSPA system is applied to study brain‐wide cerebrovascular reactivity (CVR) at single‐vessel resolution via relative changes in CBV, CBF, and SO2 in response to hypercapnia stimulation. These results show that cortical veins and arteries exhibit differences in CVR in the stimulated state and consistent anti‐correlation in CBV oscillations during the resting state, demonstrating the multiparametric fUSPA system's unique capabilities in investigating complex mechanisms of brain functions. [ABSTRACT FROM AUTHOR]

Objective Methods Results Interpretation The postictal state is underrecognized in epilepsy. Animal models show improvement of postictal symptoms and cerebral perfusion with acetaminophen or nimodipine. We studied the effects of acetaminophen or nimodipine on postictal electroencephalographic (EEG) recovery, clinical reorientation, and hypoperfusion in patients with ECT‐induced seizures.In this prospective clinical trial with three‐condition randomized crossover design, study interventions were administered orally 2 h before ECT sessions (1000 mg acetaminophen, 60 mg nimodipine, or a placebo condition). Primary outcome measure was the speed of postictal EEG recovery. Secondary outcomes were the extent of postictal EEG recovery, clinical reorientation time, and postictal cerebral blood flow as assessed by perfusion‐weighted MRI. Bayesian generalized mixed‐effects models were applied for analyses.We included 300 seizures, postictal EEGs, and reorientation time values, and 76 MRI perfusion measures from 33 patients (median age 53 years, 19 female). Pretreatment with acetaminophen or nimodipine was not associated with change in speed of EEG recovery compared to placebo (1.13 [95%CI 0.92, 1.40] and 1.07 [95%CI 0.87, 1.31], respectively), nor with the secondary outcomes. No patient reached full EEG recovery at 1 h post‐seizure, despite clinical recovery in 89%. Longer seizures were associated with slower EEG recovery and lower postictal perfusion. Nimodipine altered regional perfusion in the posterior cortex.Pretreatment with acetaminophen or nimodipine did not alleviate symptoms and signs of the postictal state. Systematic study of the postictal state after ECT‐induced seizures is feasible. [ABSTRACT FROM AUTHOR]

This document is a compilation of various scientific articles related to the neurovascular unit (NVU) and its role in mental health disorders such as depression. The articles discuss the structural and functional damage to the NVU in diabetes-related depression, the use of selective serotonin reuptake inhibitors in depression treatment, and the association between chronic stress and depression. Other topics covered include the expression of glutamine and glutamate transporter proteins in NVU cells, the concept of the NVU, and the higher blood-brain barrier permeability in patients with major depressive disorder. The document provides a comprehensive overview of the current research on the NVU and its implications for depression. [Extracted from the article]

Background: Aggression, a common symptom of Alzheimer's disease (AD), can impose a significant burden on caregivers, necessitating early institutionalization. Objective: The current study examined the neural basis of aggression and its expression mechanism, to advance the development of effective treatment strategies for aggression in patients with AD. Methods: The study sample included 257 patients; 180 were diagnosed with AD and 77 with amnestic mild cognitive impairment (aMCI). Factor analysis of the neuropsychiatric inventory (NPI) aggression scores was performed, and the correlation between each factor and cerebral blood flow (CBF) was examined via diagnosis of AD or aMCI using statistical parametric mapping. Results: Refusal of care was correlated with reduced CBF in the right hippocampus of patients with AD while no specific related regions could be identified in patients with aMCI. Violent behavior was associated with decreased CBF in the right temporal pole and medial frontal lobe of patients with AD and aMCI. Conclusions: These findings suggest that aggression, measured using NPI includes two distinct symptoms, refusal of care and violent behavior, having different underlying neural bases. [ABSTRACT FROM AUTHOR]

The objective was to assess if post‐exercise ingestion of carbonated water in a hot environment ameliorates hypotension, enhances cerebral blood flow and heat loss responses, and positively modulates perceptions and mood states. Twelve healthy, habitually active young adults (five women) performed 60 min of cycling at 45% peak oxygen uptake in a hot climate (35°C). Subsequently, participants consumed 4°C carbonated or non‐carbonated (control) water (150 and 100 mL for males and females regardless of drink type) at 20 and 40 min into post‐exercise periods. Mean arterial pressure decreased post‐exercise at 20 min only (P = 0.032) compared to the pre‐exercise baseline. Both beverages transiently (∼1 min) increased mean arterial pressure and middle cerebral artery mean blood velocity (cerebral blood flow index) regardless of post‐exercise periods (all P ≤ 0.015). Notably, carbonated water ingestion led to greater increases in mean arterial pressure (2.3 ± 2.8 mmHg vs. 6.6 ± 4.4 mmHg, P < 0.001) and middle cerebral artery mean blood velocity (1.6 ± 2.5 cm/s vs. 3.8 ± 4.1 cm/s, P = 0.046) at 20 min post‐exercise period compared to non‐carbonated water ingestion. Both beverages increased mouth exhilaration and reduced sleepiness regardless of post‐exercise periods, but these responses were more pronounced with carbonated water ingestion at 40 min post‐exercise (mouth exhilaration: 3.1 ± 1.4 vs. 4.7 ± 1.7, P = 0.001; sleepiness: −0.7 ± 0.91 vs. −1.9 ± 1.6, P = 0.014). Heat loss responses and other perceptions were similar between the two conditions throughout (all P ≥ 0.054). We show that carbonated water ingestion temporarily ameliorates hypotension and increases the cerebral blood flow index during the early post‐exercise phase in a hot environment, whereas it enhances mouth exhilaration and reduces sleepiness during the late post‐exercise phase. [ABSTRACT FROM AUTHOR]

Infection during the perinatal period can adversely affect brain development, predispose infants to ischemic stroke and have lifelong consequences. We previously demonstrated that diet enriched in n-3 polyunsaturated fatty acids (n-3 PUFA) transforms brain lipid composition in the offspring and protects the neonatal brain from stroke, in part by blunting injurious immune responses. Critical to the interface between the brain and systemic circulation is the vasculature, endothelial cells in particular, that support brain homeostasis and provide a barrier to systemic infection. Here, we examined whether maternal PUFA-enriched diets exert reprograming of endothelial cell signalling in postnatal day 9 mice after modeling aspects of infection using LPS. Transcriptome analysis was performed on microvessels isolated from brains of pups from dams maintained on 3 different maternal diets from gestation day 1: standard, n-3 enriched or n-6 enriched diets. Depending on the diet, in endothelial cells LPS produced distinct regulation of pathways related to immune response, cell cycle, extracellular matrix, and angiogenesis. N-3 PUFA diet enabled higher immune reactivity in brain vasculature, while preventing imbalance of cell cycle regulation and extracellular matrix cascades that accompanied inflammatory response in standard diet. Cytokine analysis revealed a blunted LPS response in blood and brain of offspring from dams on n-3 enriched diet. Analysis of cerebral vasculature in offspring in vivo revealed no differences in vessel density. However, vessel complexity was decreased in response to LPS at 72 h in standard and n-6 diets. Thus, LPS modulates specific transcriptomic changes in brain vessels of offspring rather than major structural vessel characteristics during early life. N-3 PUFA-enriched maternal diet in part prevents an imbalance in homeostatic processes, alters inflammation and ultimately mitigates changes to the complexity of surface vessel networks that result from infection. Importantly, maternal diet may presage offspring neurovascular outcomes later in life. [ABSTRACT FROM AUTHOR]

Wave intensity and wave speed are measures used to assess the dynamic properties of the arteries and travelling waves within the circulation. Wave intensity and wave speed measured in the carotid artery have the potential to provide hemodynamic and biophysical insights that can advance our understanding of the physiology of cerebral circulation. However, whilst studies have been performed in different patient cohorts exploring different methodological implementations of wave intensity analysis (WIA), to date little work has been done to unify wave measures or provide reference ranges on which to build the field of research and inform clinical practice. This review thus focuses on wave speed and wave intensity in the carotid artery in man with the aim to summarise the current knowledge of the field. From this review, the different methods of measurement and the disparity of the reported values currently hinder efforts to construct reference ranges for a comparator or intervention to be assessed. [ABSTRACT FROM AUTHOR]

Introduction: Orthostatic hypotension (OH) is common among the older population. The mechanism hypothesized by OH as a risk factor for cognitive decline and dementia is repeated transient cerebral blood flow deficiency. However, to our knowledge, quantitative evaluation of cardiac output and cerebral blood flow due to acute blood pressure changes resulting from postural changes is rare. Methods: We report a new fluid-structure interaction model to analyze the quantitative relationship of cerebral blood flow during OH episodes. A device was designed to simulate the aging of blood vessels. Results and Discussion: The results showed that OH was associated with decreased transient cerebral blood flow. With the arterial aging, lesions, the reduction in cerebral blood flow is accelerated. These findings suggest that systolic blood pressure regulation is more strongly associated with cerebral blood flow than diastolic blood pressure, and that more severe OH carries a greater risk of dementia. The model containing multiple risk factors could apply to analyze and predict for individual patients. This study could explain the hypothesis that transient cerebral blood flow deficiency in recurrent OH is associated with cognitive decline and dementia. [ABSTRACT FROM AUTHOR]

Objective Methods Results Interpretation To characterize the retinal microvasculature and structure in subjective cognitive decline (SCD) and identify the potential biomarker for the early stage of the Alzheimer's disease (AD) spectrum.In this study, 35 patients with SCD, 36 with cognitive impairment, and 29 with normal cognition (NC) were enrolled. Optical coherence tomography angiography was employed to assess retinal vascular density, fovea avascular zone area, and retinal thickness. The parameters reflecting retinal perfusion and structure were compared among the three groups. In addition, the association between retinal parameters, cerebral blood flow (CBF), and peripheral blood biomarkers in the SCD stage was analyzed.The superficial vascular complex (SVC) vascular density in the macula and retinal nerve fiber layer thickness in the peripapillary were significantly reduced in individuals with SCD compared to NC. Furthermore, there was a positive correlation between macular ganglion cell complex thickness and CBF in SCD.The retinal microvasculature and structure exhibit alterations in individuals with SCD. Macular ganglion cell complex thickness demonstrates correlations with cerebral perfusion. The retina holds potential as a novel biomarker for early detection of AD. [ABSTRACT FROM AUTHOR]

ABSTRACT Objective Methods Results Conclusions Intragastric administration of ninjin'yoeito (NYT), a traditional Japanese herbal medicine, reportedly prevents the decrease in baseline cerebral blood flow (CBF) in the cortex following gastric administration of water. We investigated the effect of NYT on baseline and dynamic changes in cerebral cortical arteriole diameter.Urethane‐anesthetized mice were intragastrically administered 1 g/kg NYT or distilled water (DW). The artery in the left parietal cortex was imaged using two‐photon microscopy. The baseline diameter of penetrating arterioles was measured before and 50–60 min after administration. Dynamic CBF and arteriole diameter changes before, during, and after transient occlusion of the left common carotid artery were measured approximately 10 min after administration.DW decreased the baseline diameter of the penetrating arterioles, whereas NYT did not. During occlusion, the increase in penetrating arteriole diameter was comparable for DW and NYT; however, during reperfusion, the return to preocclusion diameter was slower for NYT than DW. Laser‐speckle contrast imaging confirmed that CBF, although comparable during occlusion, was higher during reperfusion for NYT than DW.These results suggest that NYT attenuates vasoconstriction in penetrating arterioles after intragastric administration and during cerebral reperfusion, contributing to CBF regulation. [ABSTRACT FROM AUTHOR]

Cognitive decline covers a broad spectrum of disorders, not only resulting from brain diseases but also from systemic diseases, which seriously influence the quality of life and life expectancy of patients. As a highly selective anatomical and functional interface between the brain and systemic circulation, the blood-brain barrier (BBB) plays a pivotal role in maintaining brain homeostasis and normal function. The pathogenesis underlying cognitive decline may vary, nevertheless, accumulating evidences support the role of BBB disruption as the most prevalent contributing factor. This may mainly be attributed to inflammation, metabolic dysfunction, cell senescence, oxidative/nitrosative stress and excitotoxicity. However, direct evidence showing that BBB disruption causes cognitive decline is scarce, and interestingly, manipulation of the BBB opening alone may exert beneficial or detrimental neurological effects. A broad overview of the present literature shows a close relationship between BBB disruption and cognitive decline, the risk factors of BBB disruption, as well as the cellular and molecular mechanisms underlying BBB disruption. Additionally, we discussed the possible causes leading to cognitive decline by BBB disruption and potential therapeutic strategies to prevent BBB disruption or enhance BBB repair. This review aims to foster more investigations on early diagnosis, effective therapeutics, and rapid restoration against BBB disruption, which would yield better cognitive outcomes in patients with dysregulated BBB function, although their causative relationship has not yet been completely established. [ABSTRACT FROM AUTHOR]

Purpose: Posterior circulation cerebral bypasses often show higher risks and lower patency. Only few reports discussed occipital artery (OA)-vertebral artery (VA) bypasses. We present our illustrative cases to address current gaps in the literature on OA-VA bypass. Methods: A single-center retrospective review was conducted to include all institutional cases of OA-VA bypass, discussing the technique and outcomes. Results: Four institutional cases undergoing a total of 5 bypasses were evaluated, including 3 males and 1 female, with median age of 65 years (range, 62–73). All patients had vertebrobasilar insufficiency (VBI) with recurrent strokes/TIAs due to intracranial atherosclerosis, leading to unilateral VA stenosis with contralateral occlusion (1, 25%), bilateral VA stenosis (1, 25%) or occlusion (1, 25%). Medical management included aspirin for all cases (100%), with clopidogrel in 3 (75%). Surgery was performed through a far lateral approach, connecting the OA to the VA-3 segment, with no inter-positional graft. One patient underwent contralateral OA-VA bypass 6 months after the prior surgery due to worsening of the contralateral VA stenosis. Bypass patency was confirmed in all cases with post-operative angiography. All patients had clinical improvement, with one case of wound dehiscence managed conservatively. All patients were alive at last follow-up (median 7.0 months; range: 1.5–18). Conclusion: OA-VA bypass is a challenging yet effective strategy in selected patients with VBI. Current literature lacks unique definitions of surgical indications and techniques, which we addressed in our series. Surgical education should focus on expanding the microsurgery anatomy knowledge. [ABSTRACT FROM AUTHOR]

Traumatic brain injury (TBI) survivors face debilitating long-term psychosocial consequences, including social isolation and depression. TBI modifies neurovascular physiology and behavior but the chronic physiological implications of altered brain perfusion on social interactions are unknown. Adult C57/BL6 male mice received a moderate cortical TBI, and social behaviors were assessed at baseline, 3-, 7-, 14-, 30-, and 60-days post injury (dpi). Magnetic resonance imaging (MRI, 9.4T) using dynamic susceptibility contrast perfusion weighted MRI were acquired. At 60dpi mice underwent histological angioarchitectural mapping. Analysis utilized standardized protocols followed by cross-correlation metrics. Social behavior deficits at 60dpi emerged as reduced interactions with a familiar cage-mate (partner) that mirrored significant reductions in cerebral blood flow (CBF) at 60dpi. CBF perturbations were dynamic temporally and across brain regions including regions known to regulate social behavior such as hippocampus, hypothalamus, and rhinal cortex. Social isolation in TBI-mice emerged with a significant decline in preference to spend time with a cage mate. Cortical vascular density was also reduced corroborating the decline in brain perfusion and social interactions. Thus, the late emergence of social interaction deficits mirrored the reduced vascular density and CBF in regions known to be involved in social behaviors. Vascular morphology and function improved prior to the late decrements in social function and our correlations strongly implicate a linkage between vascular density, cerebral perfusion, and social interactions. Our study provides a clinically relevant timeline of alterations in social deficits alongside functional vascular recovery that can guide future therapeutics. [ABSTRACT FROM AUTHOR]

Hypothalamus is a crucial deep brain area that is responsible for the integration and coordination of various brain functions. The altered perfusion of hypothalamus during headache caused by medication-overuse headache (MOH) was previously unknown. In the current study, the altered perfusion of hypothalamic subregions in MOH patients was investigated using state-of-the-art 3D pseudo-continuous arterial spin labeling (PCASL) MR imaging. In this study, 29 normal controls subjects (NCs) and 29 MOH patients underwent 3D PCASL and brain structural MR imaging. The hypothalamus was automatically segmented into 10 subunits and the volume of each subunit was automatically determined using Freesurfer software (v7.4.1). All segmented hypothalamic subunits were converted to individual hypothalamic subunit masks. The cerebral blood flow (CBF) images were coregistered with the raw brain structural images and resliced. The CBF value of each hypothalamic subunit was extracted from the warped CBF images. The volume and CBF value of each hypothalamic subunit were analyzed using the independent sample T test and Mann–Whitney U test, receiver operating characteristic (ROC) curve analysis, and Pearson and Spearman correlation analysis. Hypothalamic subunits with significantly decreased perfusion were located in the left posterior, left tubular superior, right anterior–inferior, right tubular inferior, right tubular superior, right posterior subunit and the entire right hypothalamus [CBF value for MOH vs NC (mL/100 g·min): 48.41 ± 6.75 vs 54.08 ± 11.47, 44.44 ± 4.79 vs 48.11 ± 7.73, 41.49 (32.90, 61.46) vs 49.38 ± 10.47, 46.62 ± 7.04 vs 53.90 ± 11.75, 42.12 ± 5.74 vs 47.02 ± 9.99, 42.79 ± 5.15 vs 47.93 ± 10.48 and 43.58 ± 5.06 vs 48.65 ± 9.33, respectively] in MOH compared to NC (P < 0.05). ROC analysis for these positive subunits revealed that area under the curve was 0.658–0.693, and ROC curve for left posterior subunit had the highest specificity of 93.10% while the entire right hypothalamus had the highest sensitivity of 72.41%. Further correlation analysis showed that the CBF value of the left posterior, right anterior–inferior, right tubular superior, whole right hypothalamus presented significantly negative correlation with Hamilton Depression Scale (HAMD) score (P < 0.05). Hypoperfusion of hypothalamic subunits may contribute to the understanding of MOH pathogenesis, and the 3D PCASL could be considered as a potential diagnostic and assessment tool for MOH. [ABSTRACT FROM AUTHOR]

Highlights To examine the feasibility, utility and safety of superimposed lower body negative pressure (LBNP) and tilt during supine cycling in individuals suffering from persisting post‐concussive symptoms (PPCS). Eleven individuals aged 17–31 (6 females/5 males) participated in two randomized separate visits, 1 week apart. A ramp‐incremental test was performed during both visits until volitional failure. Visits included no pressure (control) or LBNP at −40 Torr (experimental) with head‐up tilt at 15 degrees (females) or 30 degrees (males). Transcranial Doppler ultrasound was utilized to quantify middle cerebral artery velocity (MCAv), while symptom reports were filled out before and 0, 10, and 60 min post‐exertion. Ratings of exertion and overall condition followed similar trends for participants across both tests. The relative increase in MCAv was blunted during the experimental condition (8%) compared to control (24%), while a greater heart rate (17 beats/min) was achieved during the LBNP condition (P = 0.047). Symptom severity at the 0 and 10 min post‐exertion time points displayed negligible‐to‐small effect sizes between conditions (Wilcoxon's r < 0.11). Symptom reporting was lower at the 60 min post‐exertion time point with these displaying a moderate effect size (Wilcoxon's r = 0.31). The combination of LBNP and tilt during supine cycling did not change the participants’ subjective interpretation of the exertional test but attenuated the hyperpnia‐induced vasodilatory MCAv response, while also enabling participants to achieve a higher heart rate during exercise and reduced symptoms 1 h later. As this protocol is safe and feasible, further research is warranted in this area for developing PPCS treatment options. What is the central question of this study? What are the feasibility, safety and utility of combining head‐up tilt with lower body negative pressure during supine cycling for blunting the increase in cerebral blood velocity seen during moderate‐intensity exercise in individuals experiencing persisting post‐concussion symptoms? What is the main finding and its importance? Although no differences were found in symptoms between conditions within the first 10 min following exertion, symptom severity scores showed a clinically meaningful reduction 60 min following the experimental condition compared to the non‐experimental control condition. What is the central question of this study?What are the feasibility, safety and utility of combining head‐up tilt with lower body negative pressure during supine cycling for blunting the increase in cerebral blood velocity seen during moderate‐intensity exercise in individuals experiencing persisting post‐concussion symptoms?What is the main finding and its importance?Although no differences were found in symptoms between conditions within the first 10 min following exertion, symptom severity scores showed a clinically meaningful reduction 60 min following the experimental condition compared to the non‐experimental control condition. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to assess the impact of multimodal monitoring on predicting the prognosis of patients with spontaneous intracerebral hemorrhage (SICH) and to examine the feasibility of using noninvasive near-infrared spectroscopy (NIRS) for monitoring clinical prognosis. Methods: Clinical data of 38 patients with SICH who underwent surgery in the Department of Neurosurgery of Shaanxi Provincial People’s Hospital from May 2022 to December 2022 were retrospectively analyzed. The patients were categorized into two groups based on the Glasgow Outcome Scale (GOS) 3  months after operation: poor outcome group (GOSI-III) and good outcome group (GOSIV and V). Multimodal monitoring included invasive intracranial pressure (ICP), brain temperature (BT), internal jugular venous oxygen saturation (SjvO2), and noninvasive NIRS. NIRS monitoring comprised the assessment of brain tissue oxygen saturation (StO2), blood volume index (BVI), and tissue hemoglobin index (THI). The prognostic differences between the two groups were compared. The predictive values were evaluated using the receiver operating characteristic (ROC) curve and the area under the curve (AUC). Results: ICP, BT, BVI, and THI in the good prognosis group were lower than those in the poor prognosis group. The SjvO2 and StO2 in the group with a good prognosis were higher than those in the group with a poor prognosis. Conclusion: The levels of ICP, BT, SjvO2, StO2, BVI, and THI reflect the changes in brain function and cerebral blood flow and significantly correlate with the prognosis of patients with SICH. NIRS monitoring has a high clinical utility in assessing the prognosis. [ABSTRACT FROM AUTHOR]

Objective: Endovascular thrombectomy (EVT) in patients with large infarct volume remains controversial. The aim of this study is to compare clinical outcomes between EVT and medical management in acute large vessel occlusion with infarct volumes larger than 70 mL on diffusion‐weighted magnetic resonance imaging (DWI). Methods: A prospective observational cohort study was conducted, including patients with anterior cerebral circulation occlusion due to ischemic stroke with infarct volumes larger than 70 mL within 24 h of onset between July 2018 and June 2023. Eligible patients were divided into two groups: the EVT group and the medical management (non‐EVT) group. The main outcomes were functional independence and mortality at 90 days. To assess clinical endpoints, we selected variables including age, NIHSS score, infarct volume, and occlusion location for 1:1 propensity score (PS) matching and PS adjustment using inverse probability of treatment weighting (IPTW). Results: Among the 131 identified patients (mean [SD] age, 69.9 [13.7] years; 58 female), the median infarct volume was 123.6 mL. Of these patients, 75 (57.3%) underwent EVT. After PS adjustment, EVT was not associated with functional independence (10.9% vs. 10.9%; p = 1.000) or mortality (43.5% vs. 47.8%; p = 0.675). Additionally, after PS adjustment using IPTW, EVT was also not associated with a functional independence (15.8% vs. 13.7%; p = 0.767) or mortality (46.8% vs. 44.0%; p = 0.762). Conclusion: This study provides real‐world evidence regarding infarct volumes larger than 70 mL, indicating that EVT does not provide benefits compared to medical management alone when considering age, NIHSS score, infarct volume, and occlusion location. [ABSTRACT FROM AUTHOR]

With ascent to high altitude (HA), compensatory increases in cerebral blood flow and oxygen delivery must occur to preserve cerebral metabolism and consciousness. We hypothesized that this compensation in cerebral blood flow and oxygen delivery preserves tolerance to simulated hemorrhage (via lower body negative pressure, LBNP), such that tolerance is similar during sustained exposure to HA vs. low altitude (LA). Healthy humans (4F/4 M) participated in LBNP protocols to presyncope at LA (1130 m) and 5–7 days following ascent to HA (3800 m). Internal carotid artery (ICA) blood flow, cerebral delivery of oxygen (CDO2) through the ICA, and cerebral tissue oxygen saturation (ScO2) were determined. LBNP tolerance was similar between conditions (LA: 1276 ± 304 s vs. HA: 1208 ± 306 s; P = 0.58). Overall, ICA blood flow and CDO2 were elevated at HA vs. LA (P ≤ 0.01) and decreased with LBNP under both conditions (P < 0.0001), but there was no effect of altitude on ScO2 responses (P = 0.59). Thus, sustained exposure to hypobaric hypoxia did not negatively impact tolerance to simulated hemorrhage. These data demonstrate the robustness of compensatory physiological mechanisms that preserve human cerebral blood flow and oxygen delivery during sustained hypoxia, ensuring cerebral tissue metabolism and neuronal function is maintained. [ABSTRACT FROM AUTHOR]

The accurate estimation of the tracer arterial blood concentration is crucial for reliable quantitative kinetic analysis in PET. In the current work, we demonstrate the automatic extraction of an image-derived input function (IDIF) from a CT AI-based aorta segmentation subsequently resliced to a dynamic PET series acquired on a Siemens Vision Quadra long-axial field of view scanner in 10 human subjects scanned with [15O]H2O. We demonstrate that the extracted IDIF is quantitative and in excellent agreement with a delay- and dispersion-corrected sampled arterial input function (AIF). Perfusion maps in the brain are calculated and compared from the IDIF and AIF, respectively, showed a high degree of correlation. The results demonstrate the possibility of defining a quantitatively correct IDIF compared with AIFs from the new-generation high-sensitivity and high-time-resolution long-axial field-of-view PET/CT scanners. [ABSTRACT FROM AUTHOR]

Background: Spontaneous intracerebral hemorrhage (ICH) is one of the leading causes of mortality in intensive care units. The role of systemic hyperintense inflammation (SHI) in the pathogenesis of critical complications of ICH remains a poorly understood problem. There is a specific variant of severe ICH associated with increased intracranial pressure and occlusion of intracranial vessels, defined as ineffective cerebral blood flow (IECBF). Methods: To evaluate the role of SHI in the pathogenesis of severe (comatose) ICH in a dynamic comparison of patients with IECBF (n-26) and without IECBF (n-52). The SHI integral score criterion (SI scale) was used, including certain values of plasma concentrations of IL-6, IL-8, IL-10; TNF-α, PCT, cortisol, myoglobin, troponin I, D-dimer, and, additionally, SOFA scale values. Blood levels of ACTH and neuron-specific enolase (NSE) were also assessed. Results: Twenty-eight-day mortality in severe ICH reached 84.6% (without IECBF) and 96.2% (with IECBF). Clear signs of SHI were detected in 61.5%/87.8% (without IECBF) and 0.0%/8.7% (with IECBF) within 1–3/5–8 days from the onset of ICH manifestation. The lower probability of developing SHI in the IECBF group was associated with low blood NSE concentrations. Conclusions: The development of SHI in ICH is pathogenetically related to the permeability of the blood–brain barrier for tissue breakdown products and other neuroinflammatory factors. [ABSTRACT FROM AUTHOR]

This article discusses the use of processed electroencephalography (pEEG) monitors for monitoring sedation levels in operating rooms and intensive care units. These monitors use a reduced number of electrodes placed on the frontal areas of the brain to measure brain electrical activity. The monitors provide a dimensionless scaled index to help clinicians interpret the raw EEG traces. While pEEG is recommended for monitoring anesthesia depth during general anesthesia, its utility for managing sedation in critically ill patients is still uncertain. The article also explores potential future applications of pEEG, including seizure detection, cerebral perfusion monitoring, and integration into closed-loop anesthesia delivery systems. However, solid evidence supporting these applications is currently lacking, and further research is needed. Overall, pEEG monitoring systems have potential but their limitations and the need for appropriate training should be recognized. [Extracted from the article]

Objective: This study focuses on evaluating the disruptions in key physiological parameters during microstroke events to assess their severity. Methods: A mathematical model was developed to simulate the changes in cerebral tissue pO2, glucose concentration, and temperature due to blood flow interruptions. The model considers variations in baseline cerebral blood flow (CBF), capillary density, and blood oxygen/glucose levels, as well as ambient temperature changes. Results: Simulations indicate that complete blood flow obstruction still allows for limited glucose availability, supporting nonoxidative metabolism and potentially exacerbating lactate buildup and acidosis. Partial obstructions decrease tissue pO2, with minimal impact on glucose level, which can remain almost unchanged or even slightly increase. Reduced CBF, capillary density, or blood oxygen due to aging or disease enhances hypoxia risk at lower obstruction levels, with capillary density having a significant effect on stroke severity by influencing both pO2 and glucose levels. Conditions could lead to co‐occurrence of hypoxia/hypoglycemia or hypoxia/hyperglycemia, each worsening outcomes. Temperature effects were minimal in deep brain regions but varied near the skull by 0.2–0.8°C depending on ambient temperature. Conclusions: The model provides insights into the conditions driving severe stroke outcomes based on estimated levels of hypoxia, hypoglycemia, hyperglycemia, and temperature changes. [ABSTRACT FROM AUTHOR]

Objective: We attempted to record the regional cerebral blood flow (CBF) simultaneously at various regions of the cerebral cortex and the striatum during middle cerebral artery (MCA) occlusion and to evaluate neurological deficits and infarct formation. Methods: In male C57BL/6J mice, CBF was recorded in three regions including the ipsilateral cerebral cortex and the striatum with laser Doppler flowmeters, and the origin of MCA was occluded with a monofilament suture for 15–90 min. After 48 h, neurological deficits were evaluated, and infarct was examined by triphenyltetrazolium chloride (TTC) staining. Results: CBF decrease in the striatum was approximately two‐thirds of the MCA‐dominant region of the cortex during MCA occlusion. The characteristic CBF fluctuation because of spontaneously occurred spreading depolarization observed throughout the cortex was not found in the striatum. Ischemic foci with slight lower staining to TTC were found in the ipsilateral striatum in MCA‐occluded mice for longer than 30 min (n = 54). Twenty‐nine among 64 MCA‐occluded mice exhibited neurological deficits even in the absence of apparent infarct with minimum staining to TTC in the cortex, and the severity of neurological deficits was not correlated with the size of the cortical infarct. Conclusion: Neurological deficits might be associated with the ischemic striatum rather than with cortical infarction. [ABSTRACT FROM AUTHOR]

Mild–moderate traumatic brain injuries (TBIs) are prevalent, and while many individuals recover, there is evidence that a significant number experience long‐term health impacts, including increased vulnerability to neurodegenerative diseases. These effects are influenced by other risk factors, such as cardiovascular disease. Our study tested the hypothesis that a pre‐injury reduction in cerebral blood flow (CBF), mimicking cardiovascular disease, worsens TBI recovery. We induced bilateral carotid artery stenosis (BCAS) and a mild–moderate closed‐head TBI in male and female mice, either alone or in combination, and analyzed CBF, spatial learning, memory, axonal damage, and gene expression. Findings showed that BCAS and TBI independently caused a ~10% decrease in CBF. Mice subjected to both BCAS and TBI experienced more significant CBF reductions, notably affecting spatial learning and memory, particularly in males. Additionally, male mice showed increased axonal damage with both BCAS and TBI compared to either condition alone. Females exhibited spatial memory deficits due to BCAS, but these were not worsened by subsequent TBI. Gene expression analysis in male mice highlighted that TBI and BCAS individually altered neuronal and glial profiles. However, the combination of BCAS and TBI resulted in markedly different transcriptional patterns. Our results suggest that mild cerebrovascular impairments, serving as a stand‐in for preexisting cardiovascular conditions, can significantly worsen TBI outcomes in males. This highlights the potential for mild comorbidities to modify TBI outcomes and increase the risk of secondary diseases. [ABSTRACT FROM AUTHOR]

Purpose: After a traumatic brain injury (TBI), monitoring of both macrovascular and microvascular blood circulation can potentially yield a better understanding of pathophysiology of potential secondary brain lesions. We investigated the changes in phase shift (PS) between cardiac-induced oscillations of cerebral blood flow (CBF) measured at macro (ultrasound Doppler) and microvascular (laser Doppler) level. Further we assessed the impact of intracranial pressure (ICP) on PS in TBI patients. A secondary aim was to compare PS to TCD-derived cerebral arterial time constant (τ), a parameter that reflects the circulatory transit time. Methods: TCD blood flow velocities (FV) in the middle cerebral artery, laser Doppler blood microcirculation flux (LDF), arterial blood pressure (ABP), and ICP were monitored in 29 consecutive patients with TBI. Eight patients were excluded because of poor-quality signals. For the remaining 21 patients (median age = 23 (Q1: 20–Q3: 33); men:16,) data were retrospectively analysed. PS between the fundamental harmonics of FV and LDF signals was determined using spectral analysis. τ was estimated as a product of cerebrovascular resistance and compliance, based on the mathematical transformation of FV and ABP, ICP pulse waveforms. Results: PS was negative (median: −26 (Q1: −38–Q3: −15) degrees) indicating that pulse LDF at a heart rate frequency lagged behind TCD pulse. With rising mean ICP, PS became more negative (R = −0.51, p < 0.019) indicating that delay of LDF pulse increases. There was a significant correlation between PS and cerebrovascular time constant (R = −0.47, p = 0.03). Conclusions: Pulse divergence between FV and LDF became greater with elevated ICP, likely reflecting prolonged circulatory travel time. [ABSTRACT FROM AUTHOR]

Thrombosis in antiphospholipid syndrome (APS) involves in most cases the venous circulation. Why in some patients thrombotic APS affects the arterial circulation and in particular cerebral circulation is unknown. In previous studies, both patient characteristics and antiphospholipid antibody types and titers have been associated with arterial thrombosis. Aim of this study was to compare the clinical characteristics and laboratory findings of venous and arterial thrombotic APS from a large series of patients. Data were retrieved from the Start 2 antiphospholipid, a multicenter prospective register of long-term collected data from Thrombosis Centers in Italy. Of 167 patients with thrombotic APS, 114 (68 %) had a venous and 53 (32 %) had an arterial event as first clinical manifestation. Several clinical characteristics and risk factors were different among groups in univariate analysis. Using logistic regression analysis, reduced creatinine clearance and hyperlipidemia were independent variable for the occurrence of arterial APS. Notably, no difference in antiphospholipid antibody profiles and aβ2-Glycoprotein I levels were found between groups. A higher adjusted global antiphospholipid syndrome score (aGAPSS) was found in arterial group indicating a possible high recurrence rate in arterial APS. These data have pathophysiological and clinical implication since associated conditions might predispose patients to arterial rather than venous events and call to a close monitoring and treatment of arterial APS due to their increased tendency to recurrence. [ABSTRACT FROM AUTHOR]

This case report presents a rare case of infantile nystagmus syndrome (INS) in which the direction of infantile nystagmus (IN) was vertical. A 66-year-old woman was referred to our department for investigation of abnormal eye movements. She showed a disordered field of view with a homonymous hemianopia in the lower left quadrant and vertical gaze-evoked nystagmus, but there were no other abnormal neurological findings. She did not complain of an oscillopsia. Imaging revealed that the cause of hemianopia was atrophy and low cerebral blood flow in the right occipital lobe. The vertical nystagmus became strong when attempting to fixate to stationary targets. A reversed optokinetic nystagmus response was observed in the vertical optokinetic nystagmus test. From these eye movements, we diagnosed her nystagmus as vertical IN. Patients with INS see everything by saccades. IN consists of the alternate appearance of saccades and preceding slow eye movements. For these eye movements, a wide visual field is necessary. In this case, vertical IN was caused by the wider vertical than horizontal visual field resulting from homonymous hemianopia. Therefore, the direction of IN is horizontal in most patients with INS because their horizontal visual field is the widest field. [ABSTRACT FROM AUTHOR]

OBJECTIVES: The first aim was to investigate the combined effect of insult intensity and duration of the pressure reactivity index (PRx) and deviation from the autoregulatory cerebral perfusion pressure target (ΔCPPopt = actual CPP -- optimal CPP [CPPopt]) on outcome in traumatic brain injury. The second aim was to determine if PRx influenced the association between intracranial pressure (ICP), CPP, and ΔCPPopt with outcome. DESIGN: Observational cohort study. SETTING: Neurocritical care unit, Cambridge, United Kingdom. PATIENTS: Five hundred fifty-three traumatic brain injury patients with ICP and arterial blood pressure monitoring and 6-month outcome data (Glasgow Outcome Scale [GOS]). INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: The insult intensity (mm Hg or PRx coefficient) and duration (minutes) of ICP, PRx, CPP, and ΔCPPopt were correlated with GOS and visualized in heatmaps. In these plots, there was a transition from favorable to unfavorable outcome when PRx remained positive for 30 minutes and this was also the case for shorter durations when the intensity was higher. In a similar plot of ΔCPPopt, there was a gradual transition from favorable to unfavorable outcome when ΔCPPopt went below -5 mm Hg for 30-minute episodes of time and for shorter durations for more negative ΔCPPopt. Furthermore, the percentage of monitoring time with certain combinations of PRx with ICP, CPP, and ΔCPPopt were correlated with GOS and visualized in heatmaps. In the combined PRx/ICP heatmap, ICP above 20 mm Hg together with PRx above 0 correlated with unfavorable outcome. In a PRx/CPP heatmap, CPP below 70 mm Hg together with PRx above 0.2-0.4 correlated with unfavorable outcome. In the PRx-/ΔCPPopt heatmap, ΔCPPopt below 0 together with PRx above 0.2-0.4 correlated with unfavorable outcome. CONCLUSIONS: Higher intensities for longer durations of positive PRx and negative ΔCPPopt correlated with worse outcome. Elevated ICP, low CPP, and negative ΔCPPopt were particularly associated with worse outcomes when the cerebral pressure autoregulation was concurrently impaired. [ABSTRACT FROM AUTHOR]

Background: Posterior reversible encephalopathy syndrome (PRES) is characterized by cerebral blood flow dysregulation and the blood–brain barrier (BBB) disruption. While renal insufficiency has been considered a factor in BBB fragility, the relationship between renal insufficiency and the PRES lesions volume remains unclear. Methods: This observational study was performed retrospectively. PRES patients were categorized into two groups with renal insufficiency, defined as an estimated glomerular filtration rate (eGFR) of less than 60 mL/min/1.73m2 on the day of symptom occurrence. Lesion volume was measured using fluid-attenuated inversion recovery (FLAIR) imaging, and the brain was divided into nine regions. The volume of the parietal-occipital-temporal lobe was considered typical, while the other six regions were labeled as atypical. Results: The study included 200 patients, of whom 94 (47%) had renal insufficiency. Patients with renal insufficiency had a larger lesion volume (144.7 ± 125.2 cc) compared to those without renal insufficiency (110.5 ± 93.2 cc; p = 0.032); particularly in the atypical lesions volume (49.2 ± 65.0 vs. 29.2 ± 44.3 cc; p = 0.013). However, there was no difference in the reversibility of the lesions (35.2 ± 67.5 vs. 18.8 ± 33.4 cc; p = 0.129). Multiple regression analysis revealed that decreases in eGFR (β = -0.34, 95% CI -0.62-0.05, p = 0.020) were positively associated with total lesion volume. Conclusion: Our findings suggest that PRES patients with renal insufficiency experience more severe lesion volumes, likely due to the atypical brain regions involvement. The lesions involving atypical regions may have a similar pathophysiology to typical lesions, as the PRES lesions reversibility was found to be similar between individuals with and without renal insufficiency. [ABSTRACT FROM AUTHOR]

Cannabinoid use, particularly for recreational purposes, is increasing exponentially across all age groups, especially in younger populations, due to its perceived low risk and legalization. While cannabinoids may be largely considered as safe, there is mounting evidence of increased risk of systemic and neurological complications through their interaction with the poorly understood endocannabinoid receptor network within the central nervous system and other organ systems. Acute cannabinoid exposure can cause neuropsychiatric symptoms in addition to altering cerebral blood flow, leading to cerebrovascular complications such as ischemic stroke, subarachnoid hemorrhage, and reversible cerebral vasoconstriction syndrome (RCVS). Chronic use, particularly among adolescents, may be associated with increased risk of long-term cognitive deficits, schizophrenia, and other neuropsychiatric effects. Synthetic cannabinoids have increased potency, with reports of causing profound neurological complications including coma, seizures, posterior reversible encephalopathy syndrome, and RCVS. Despite increasing evidence, the quality of literature describing neurologic complications with cannabinoids remains limited to case series and retrospective cohort studies, with significant confounding factors such as concomitant use of other illicit drugs, limiting interpretation. In this review, we summarize the effect of cannabinoids on the neurologic system and associated neurological complications. [ABSTRACT FROM AUTHOR]

Moyamoya disease is characterized by progressive internal carotid artery (ICA) occlusion. Extracranial-intracranial bypass surgery is effective, particularly in pediatric patients; imaging plays a crucial role in evaluating intracranial perfusion pre- and post-surgery. Arterial spin labeling (ASL) is a magnetic resonance technique employed for noninvasive, whole-brain perfusion assessment by magnetically labeling inflowing blood. However, ASL cannot evaluate the territories and development of each vessel perfusion compared with digital subtraction angiography (DSA). Recently, super-selective ASL (SS-ASL) has been developed, performing pinpoint labeling on a specific artery at a time, and offering a tomographic view that distinctly displays blood supply areas for each vessel. Unlike DSA, SS-ASL is noninvasive and can be repeatedly performed in pediatric patients. In conclusion, SS-ASL is useful for evaluating bypass development over time and understanding the pathophysiology of pediatric moyamoya disease. [ABSTRACT FROM AUTHOR]

In recent years, ultra-high-field magnetic resonance imaging (MRI) applications have been rapidly increasing in both clinical research and practice. Indeed, 7-Tesla (7T) MRI allows improved depiction of smaller structures with high signal-to-noise ratio, and, therefore, may improve lesion visualization, diagnostic capabilities, and thus potentially affect treatment decision-making. Incremental evidence emerging from research over the past two decades has provided a promising prospect of 7T magnetic resonance angiography (MRA) in the evaluation of intracranial vasculature. The ultra-high resolution and excellent image quality of 7T MRA allow us to explore detailed morphological and hemodynamic information, detect subtle pathological changes in early stages, and provide new insights allowing for deeper understanding of pathological mechanisms of various cerebrovascular diseases. However, along with the benefits of ultra-high field strength, some challenges and concerns exist. Despite these, ongoing technical developments and clinical oriented research will facilitate the widespread clinical application of 7T MRA in the near future. In this review article, we summarize technical aspects, clinical applications, and recent advances of 7T MRA in the evaluation of intracranial vascular disease. The aim of this review is to provide a clinical perspective for the potential application of 7T MRA for the assessment of intracranial vascular disease, and to explore possible future research directions implementing this technique. [ABSTRACT FROM AUTHOR]

Background The novel Contour Neurovascular System (Contour) has been reported to be efficient and safe for the treatment of intracranial, wide-necked bifurcation aneurysms. Flow in the aneurysm and posterior cerebral arteries (PCAs) after Contour deployment has not been analyzed in detail yet. However, this information is crucial for predicting aneurysm treatment outcomes. Methods Time-resolved three-dimensional velocity maps in 14 combinations of patient-based basilar tip aneurysm models with and without Contour devices (sizes between 5 and 14 mm) were analyzed using four-dimensionsal (4D) flow MRI and numerical/image-based flow simulations. A complex virtual processing pipeline was developed to mimic the experimental shape and position of the Contour together with the simulations. Results On average, the Contour significantly reduced intra-aneurysmal flow velocity by 67% (mean w/ = 0.03m/s; mean w/o = 0.12m/s; p-value=0.002), and the time-averaged wall shear stress by more than 87% (mean w/ = 0.17Pa; mean w/o = 1.35Pa; pvalue= 0.002), as observed by numerical simulations. Furthermore, a significant reduction in flow (P<0.01) was confirmed by the neck inflow rate, kinetic energy, and inflow concentration index after Contour deployment. Notably, device size has a stronger effect on reducing flow than device positioning. However, positioning affected flow in the PCAs, while being robust in effectively reducing flow. Conclusions This study showed the high efficacy of the Contour device in reducing flow within aneurysms regardless of the exact position. However, we observed an effect on the flow in PCAs, which needs to be investigated further. [ABSTRACT FROM AUTHOR]