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The clinical value of magnetic resonance angiography (MRA), transcranial Doppler ultrasound (TCD) and electroencephalogram (EEG) in the diagnosis of intracranial artery stenosis in ischemic cerebrovascular disease (ICVD) was explored. The clinical data of TCD, MRA and EEG in 98 patients with ICVD were retrospectively analyzed. The clinical value of TCD, MRA combined with EEG in the diagnosis of intracranial artery stenosis in ICVD was analyzed based on the results of digital subtraction angiography (DSA) as the gold standard. A total of 98 patients were diagnosed with 27 cases of normal intracranial artery, 32 cases of mild stenosis, 25 cases of moderate stenosis, and 14 cases of severe stenosis DSA examination. TCD was detected in 23 cases of normal, 25 cases of mild stenosis, 23 cases of moderate stenosis and 13 cases of severe stenosis. MRA showed 24 cases of normal, 28 cases of mild stenosis, 21 cases of moderate stenosis and 12 cases of severe stenosis. EEG examination detected that there were 25 cases of normal, 24 cases of mild stenosis, 22 cases of moderate stenosis, and 14 cases of severe stenosis. Sensitivity, accuracy and negative predictive value had significant differences between combined diagnosis and single diagnosis. The combined detection of TCD, MRA and EEG is consistent with DSA detection in the diagnosis of ICVD intracranial artery stenosis. [ABSTRACT FROM AUTHOR]

Blood velocities measured by Transcranial Doppler (TCD) are dependent on the angle between the incident ultrasound beam and the direction of blood flow (known as the Doppler angle). However, when TCD examinations are performed without imaging the Doppler angle for each vessel segment is not known. We have measured Doppler angles in the basal cerebral arteries examined with TCD using three-dimensional (3D) vessel models generated from computed tomography angiography (CTA) scans. This approach produces angle statistics that are not accessible during non-imaging TCD studies. We created 3D models of the basal cerebral arteries for 24 vasospasm patients. Standard acoustic windows were mapped to the specific anatomy of each patient. Virtual ultrasound transmit beams were generated that originated from the acoustic window and intersected the centerline of each arterial segment. Doppler angle measurements were calculated and compiled for each vessel segment. Doppler angles were smallest for the middle cerebral artery M1 segment (median 24.6°) and ophthalmic artery (median 25.0°), and largest for the anterior cerebral artery A2 segment (median 76.4°) and posterior cerebral artery P2 segment (median 75.8°). The ophthalmic artery had the highest proportion of Doppler angles that were less than 60° (99%) while the anterior cerebral artery A2 segment had the lowest proportion of Doppler angles that were less than 60° (10%). These angle measurements indicate the expected deviation between measured and true velocities in the cerebral arteries, highlighting specific segments that may be prone to underestimation of velocity. [ABSTRACT FROM AUTHOR]

Abstract Background At present, the most effective treatment for symptomatic moyamoya disease (MMD) is surgery. However, the high incidence of postoperative complications is a serious problem plaguing the surgical treatment of MMD, especially the acute cerebral infarction. Decreased cerebrovascular reserve is an independent risk factor for ischemic infarction, and the pulsatility index (PI) of transcranial Doppler (TCD) is a common intuitive index for evaluating intracranial vascular compliance. However, the relationship between PI and the occurrence of ischemic stroke after operation is unclear. Objective To explore whether the PI in the middle cerebral artery (MCA) could serve as a potential predictor for the occurrence of ischemic infarction after bypass surgery in MMD. Methods We performed a retrospective analysis of data from 71 patients who underwent combined revascularization surgery, including superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis and encephalo-duro-myo-synangiosis (EDMS). The patients were divided into two groups according to the median of ipsilateral MCA-PI before operation, low PI group (MCA-PI

Background: At present, the most effective treatment for symptomatic moyamoya disease (MMD) is surgery. However, the high incidence of postoperative complications is a serious problem plaguing the surgical treatment of MMD, especially the acute cerebral infarction. Decreased cerebrovascular reserve is an independent risk factor for ischemic infarction, and the pulsatility index (PI) of transcranial Doppler (TCD) is a common intuitive index for evaluating intracranial vascular compliance. However, the relationship between PI and the occurrence of ischemic stroke after operation is unclear. Objective: To explore whether the PI in the middle cerebral artery (MCA) could serve as a potential predictor for the occurrence of ischemic infarction after bypass surgery in MMD. Methods: We performed a retrospective analysis of data from 71 patients who underwent combined revascularization surgery, including superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis and encephalo-duro-myo-synangiosis (EDMS). The patients were divided into two groups according to the median of ipsilateral MCA-PI before operation, low PI group (MCA-PI < 0.614) and high PI group (MCA-PI ≥ 0.614). Univariate and multivariate regression analysis were used to explore risk factors affecting the occurrence of postoperative cerebral infarction. Results: Among the 71 patients with moyamoya disease, 11 patients had cerebral infarction within one week after revascularization. Among them, 10 patients' ipsilateral MCA-PI were less than 0.614, and another one's MCA- PI is higher than 0.614. Univariate analysis showed that the lower ipsilateral MCA-PI (0.448 ± 0.109 vs. 0.637 ± 0.124; P = 0.001) and higher Suzuki stage (P = 0.025) were linked to postoperative cerebral infarction. Multivariate analysis revealed that lower ipsilateral MCA-PI was an independent risk factor for predicting postoperative cerebral infarction (adjusted OR = 14.063; 95% CI = 6.265 ~ 37.308; P = 0.009). Conclusions: A lower PI in the ipsilateral MCA may predict the cerebral infarction after combined revascularization surgery with high specificity. And combined revascularization appears to be safer for the moyamoya patients in early stages. [ABSTRACT FROM AUTHOR]

Objective: Transcarotid artery revascularization (TCAR) has emerged as a safe and effective method for carotid revascularization, offering several key advantages over carotid endarterectomy (CEA) and carotid artery stenting (CAS). Intraoperative transcranial Doppler (TCD) monitoring plays a pivotal role in assessing cerebral hemodynamics and detecting embolic signals during TCAR at our institution. Methods: This review synthesizes the current literature and provides guidance for TCD monitoring throughout the various phases of TCAR, from preoperative assessment to postoperative management. Key considerations include probe placement, waveform evaluation, interpreting monitoring parameters such as mean flow velocity (MFV), pulsatility index (PI), and percentage change in the MFV (Δ%). Techniques for maintaining the insonation of the middle cerebral artery (MCA) M1 segment and optimal parameter settings for intraoperative TCD monitoring are detailed. Results: TCAR phases are highlighted, including transcarotid access and vessel control, sheath insertion, the establishment of flow reversal, pre-dilation, stent placement, post-dilation, and closure, while emphasizing the importance of real-time feedback provided by TCD monitoring in identifying embolic signals and assessing changes in cerebral perfusion. The review discusses limitations of TCD monitoring, such as inadequate temporal windows, incorrect vessel identification and reliability issues with automatic emboli detection counters. Furthermore, practical advice is provided on how to navigate common pitfalls encountered during intraoperative TCD monitoring. Conclusion: By understanding the nuances of TCD monitoring and its application in TCAR, intraoperative TCD monitoring may aid to minimize the low but potential risk of intraprocedural embolic events, periprocedural hypoperfusion and postoperative hyperperfusion. Finally, we suggest opportunities for further research in embolization quantification and additional strategies to optimize quality control in TCAR.

Introduction: Sensitisation of the nervous system in a patient with migraine is supposed to be associated with calcitonin gene-related peptide (CGRP) activity. Therefore, the vascular response to human aCGRP (haCGRP) could be a surrogate marker for the sensitization. We hypothesize that vascular response to hαCGRP is augmented in a patient with migraine. Methods: Twenty healthy subjects and 20 patients with migraine participated in our study. TCD was used to monitor mean arterial velocity in the middle cerebral artery (vm MCA). Simultaneously, end-tidal CO2 (Et-CO2), mean arterial pressure (MAP), and heart rate (HR) were measured. The reconstruction of the signals was made for basal conditions, during and after CGRP infusion which were compared using statistics. Results: In both groups, we found significant decrease between measurement points of vm MCA and Et-CO2 during and after hαCGRP infusion. MAP did not show significant trends during the infusion, but it was significantly increased after the infusion in migraine patients only. Responses to hαCGRP, defined as differences between two measurement points, were significantly higher for vm MCA and Et-CO2 in patients with migraine. A significant difference between groups was found inMAP response. Significant relationships were found between migraine and vm MCA, Et-CO2, and MAP. Conclusion: In patients with migraine, vm MCA responses to hαCGRP are significantly higher and are associated with CGRP-induced headache which indicates that patients with migraine are more prone to sensitization. [ABSTRACT FROM AUTHOR]

Background: The prevalence and causes of intra cranial arterial stenosis in adults' stroke patients is largely unknown. Hence it has become a great clinical challenge for Neuro-physician, neurosurgeon and radiologist to find out the aetiologies of intra cranial arterial stenosis. Method: 100 patients of aged between 25 to 60 years were selected for study. Their past history and clinical manifestations were noted TCD examination was performed with portable machine (multi-drop (R) + DWL), which is a 2MHz power motion single channel TCD, MCA was approached through temporal windows by use of standard protocol. stenosis of arteries were defined by the peak systolic flow velocity more than 140 cm/sec for MCA. Results: The highest clinical manifestation was HTN 75%, followed by DM 58%, obesity 52% and hyper cholestremia 48%, smoker 38%, CAD 32% and least was PVD 2%. In odds ratio study HTN was highest 8.5, followed by CAD ratio was 6 and least ratio was alcoholics 1.6. Conclusion: The present study revealed the aggravating factor like HTN, DM, and CAD. Atherosclerosis causes stenosis of MCA and peak systolic velocity more than 140 mc/sec for MCA. Hence the patients having such clinical manifestations will be more prone for stenosis of MCA. [ABSTRACT FROM AUTHOR]

Use of thoracoabdominal normothermic regional perfusion (TA-NRP) during donation after circulatory death (DCD) is an important advance in organ donation. Prior to establishing TA-NRP, the brachiocephalic, left carotid, and left subclavian arteries are ligated, thereby eliminating anterograde brain blood flow via the carotid and vertebral arteries. While theoretical concerns have been voiced that TA-NRP after DCD may restore brain blood flow via collaterals, there have been no studies to confirm or refute this possibility. We evaluated brain blood flow using intraoperative transcranial Doppler (TCD) in two DCD TA-NRP cases. Pre-extubation, anterior and posterior circulation brain blood flow waveforms were present in both cases, similar to the waveforms detected in a control patient on mechanical circulatory support undergoing cardiothoracic surgery. Following declaration of death and initiation of TA-NRP, no brain blood flow was detected in either case. Additionally, there was absence of brainstem reflexes, no response to noxious stimuli and no respiratory effort. These TCD results demonstrate that DCD with TA-NRP did not restore brain blood flow. [ABSTRACT FROM AUTHOR]

Abstract Point-of-care ultrasound (POCUS) is an essential tool to assess and manage different pathologies in the intensive care unit, and many protocols have been proposed for its application in critical care literature. However, the brain has been overlooked in these protocols. Brain ultrasonography (BU) is easily available, and it allows a goal-directed approach thanks to its repeatability and immediate interpretation and provides a quick management and real time assessment of patients’ conditions. Based on recent studies, the increasing interest from intensivists, and the undeniable benefits of ultrasound, the main goal of this overview is to describe the main evidence and progresses in the incorporation of BU into the POCUS approach in the daily practice, and thus becoming POCUS-BU. This integration would allow a noninvasive global assessment to entail an integrated analysis of the critical care patients.

The Theory of Critical Distances (TCD) has undoubtedly represented a breakthrough in the brittle failure assessment of engineering materials containing defects, crack, or notches. The basic idea on which the simplest formulation of the TCD is based is to evaluate an effective stress at a characteristic distance from the tip of the defect/crack/notch and compare it with an inherent fracture strength. Is the critical distance related to the material (micro) structure? Whereas a correlation was already proved for homogeneous materials, the current attention to nonhomogeneous ones has brought the question back to the fore. The goal of the present work is therefore twofold: (i) to extend the use of the TCD, through the simple yet effective Point Method (PM), for the static failure assessment of inhomogeneous materials, such as cellular, biological, and additively manufactured (AM) materials; and (ii) to look for a correlation between critical distance and internal (micro) structure. Highlights: The use of TCD is extended to the static assessment of inhomogeneous materials.The failure behavior of natural, biological, and AM materials is investigated.PM failure predictions are generally included in an error interval of ±10%.The critical distance L is related to the material microstructure. [ABSTRACT FROM AUTHOR]

Traumatic brain injury (TBI) is a worldwide public health concern given its significant morbidity and mortality, years of potential life lost, reduced quality of life and elevated healthcare costs. The primary injury occurs at the moment of impact, but secondary injuries might develop as a result of brain hemodynamic abnormalities, hypoxia, and hypotension. The cerebral edema and hemorrhage of the injured tissues causes a decrease in cerebral perfusion pressure (CPP), which leads to higher risk of cerebral ischemia, herniation and death. In this setting, our role as physicians is to minimize damage by the optimization of the CPP and therefore to reduce mortality and improve neurological outcomes. Performing a transcranial doppler ultrasound (TCD) allows to estimate cerebral blood flow velocities and identify states of low flow and high resistance. We propose to include TCD as an initial assessment and further monitoring tool for resuscitation guidance in patients with severe TBI. We present an Ultrasound-Guided Cardio-cerebral Resuscitation (UGCeR) protocol in Patients with Severe TBI. [ABSTRACT FROM AUTHOR]

Intracranial atherosclerotic ischemic stroke dramatically impacts the quality of life among the elderly. Statins therapy has been proven to be effective in plaque stabilization and alleviation in patients with intracranial atherosclerotic ischemic stroke. According to recent studies, these effects may be directly related to lipid levels rather than specific lipid-lowering drugs. Anti-proprotein convertase subtilisin/kexin type 9 (PCSK9) monoclonal antibodies (PCSK-9 inhibitor) are newer effective lipid-lowering drugs increasingly prescribed to patients at high cardiovascular risk to lower LDL cholesterol. Studies have provided evidence that PCSK9 inhibitor combined with statin therapy can lead to a decrease in the plaque volume measured by intravascular ultrasound in coronary heart disease patients. But the efficacy of combination of the two drugs in symptomatic intracranial artery stenosis has been unknown. Here we provide a case which was reported to suggest that a combination of Evolocumab and intensive statin therapy might reverse or alleviate symptomatic intracranial artery stenosis.

Background and purpose: Transcranial doppler ultrasound (TCD) is a tool that diagnoses and monitors pathophysiological changes to the cerebrovasculature. As cerebral blood flow velocities (CBFVs) increase throughout childhood, interpretation of TCD examinations in pediatrics requires comparison to age matched normative data. Large cohorts of healthy children have not been examined to develop these reference values in any population. There is a complete absence of normative values in African children where, due to lack of alternate neuroimaging techniques, utilization of TCD is rapidly emerging. Materials and methods: A prospective study of 710 healthy African children 3 months-15 years was performed. Demographics, vital signs, and hemoglobin values were recorded. Participants underwent a complete, non-imaging TCD examination. Systolic (Vs), diastolic (Vd), and mean (Vm) flow velocities and pulsatility index (PI) were calculated by the instrument for each measurement. Results: Vs, Vd, and Vm increased through early childhood in all vessels, with the highest CBFVs identified in children 5–5.9 years. There were few significant gender differences in CBFVs in any vessels in any age group. No correlations between blood pressure or hemoglobin and CBFVs were identified. Children in the youngest age groups had CBFVs similar to those previously published, whereas nearly every vessel in children ≥3 years had significantly lower Vs, Vd, and Vm. Conclusions: For the first time, reference TCD values for African children are established. Utilization of these CBFVs in the interpretation of TCD examinations in this population will improve the overall accuracy of TCD as a clinical tool on the continent.

Point-of-care ultrasound (POCUS) is an essential tool to assess and manage different pathologies in the intensive care unit, and many protocols have been proposed for its application in critical care literature. However, the brain has been overlooked in these protocols. Brain ultrasonography (BU) is easily available, and it allows a goal-directed approach thanks to its repeatability and immediate interpretation and provides a quick management and real time assessment of patients' conditions. Based on recent studies, the increasing interest from intensivists, and the undeniable benefits of ultrasound, the main goal of this overview is to describe the main evidence and progresses in the incorporation of BU into the POCUS approach in the daily practice, and thus becoming POCUS-BU. This integration would allow a noninvasive global assessment to entail an integrated analysis of the critical care patients. [ABSTRACT FROM AUTHOR]

The use of unequal-thickness butt-welded joints is widespread in bridge engineering, material savings mean a decrease in cost, which can lead to lower overall costs and significant benefits Because of their unique structures and propensity for stress concentration and weld defects, it is crucial to investigate their fatigue performance. In this study, 15 sets of unequal-thickness butt-welded joints based on Q420qFNH were subjected to fatigue tests. ABAQUS modelling and a stress-extraction process utilising distance iterations were employed in this study. The key findings demonstrated that the fatigue performance of these weathering steel butt joints was superior, and the stress variation at these joints exhibited greater complexity and resulted in a more pronounced multi-crack fusion effect. Additionally, an attempt was made to evaluate the fatigue behaviour of other welded joints and unequal-thickness butt-welded joints using the same approach as that presented herein. The fatigue evaluation method based on nominal stress yielded a significant scatter of 1:T s = 4.21. Iterations were conducted based on the scattering at various critical distances. The results indicate that based on the theory of critical distance, the scatter of 1:T s = 2.304 is lower than the scatter of 1:T s = 2.502 associated with the notch stress method. These findings suggest that employing this method for fatigue assessment yields favourable outcomes across diverse welded joints. • Fatigue tests of Q420qFNH weathering steel in the unequal-thickness butt-welded joint was carried out. • The fatigue failures of Q420qFNH weathering steel in the unequal-thickness butt-welded joint were investigated. • The theory of critical distance-based assessment method was adopted to estimate the fatigue resistance. [ABSTRACT FROM AUTHOR]

• The fracture of a new third generation AW2099-T83 alloy was examined. • U and V notched specimens were tested under quasi-static loading. • A machine learning model was successfully used to estimate the fracture loads. • The theory of critical distance was used for estimating the fracture loads. • The strain energy density criterion was used for estimating the fracture loads. Aluminum–lithium (Al–Li) alloys offer superior performance under different conditions that involve mechanical loading, high temperature and corrosive environment. Therefore, Al–Li alloys are being used in the defense, aerospace, and aircraft industries, specifically in structural parts such as fuselage, empennage, and wings. By modifying the chemical composition, a third generation of Al–Li alloys has been introduced to overcome the mechanical and thermal shortcomings of previous Al–Li generations. As structural parts usually contain notches, it is of paramount importance to study the strength of the newly introduced alloys in the presence of such geometrical discontinuities to select the suitable alloy for a particular application. The aim of this work is to analyze the strength of U and V-notched specimens machined from extruded AW2099-T83 Al–Li alloys under quasi-static loading. The fracture stress of specimens with various notch radii and angles were estimated using strain energy density (SED) and the theory of critical distances (TCD) methods. A support vector machine (SVM) regression model was also implemented to assess the applicability of estimating fracture stress using machine learning approaches. The results show an average absolute discrepancy of 6.6 %, 7.8 % and 2.8 % for SED, TCD and SVM methods, respectively. [ABSTRACT FROM AUTHOR]

The role of nimodipine and milrinone in the management of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (SAH) was studied using clinical and TCD (transcranial Doppler) parameters. In this prospective observational study, patients with DCI after aneurysmal SAH presenting between November 2020 and June 2021 who were treated by either intra-arterial nimodipine (IAN) or intravenous milrinone (IVM) were included after excluding patients in whom both IAN and IVM had been given or mechanical angioplasty was performed. Twelve-hourly TCD was performed during the course of the therapy. Clinical improvement and the development of new brain infarcts were also assessed. A P value <0.05 was considered statistically significant. Thirty-four patients fulfilled the inclusion criteria (IVM, 13/34 [38%]; IAN, 21/34 [62%]); patients in the IVM group (vs. IAN group) had poorer median Glasgow Coma Scale score (12 vs. 13), poorer motor response (

Background: In many pregnant women, it is very difficult to accurately assess the fetal gestation age, due to pregnancy on top of lactation or contraceptive method, unsure of date, irregular cycles, late booking and missing the dating scan. Therefore, we might have a wrong diagnosis of preterm or postterm pregnancy, which will affect the outcome of pregnancy. Patients and methods: In our prospective study, we examined 70 normal pregnant women and 70 intrauterine growth restricted (IUGR) pregnancy cases after Ethical Committee approval and informed written consent, to assess the effectivity of transcerebellar diameter (TCD) in detection the age of gestation in normal pregnancy and IUGR cases in relation to other ultrasound parameters as biparietal diameter (BPD), head circumference (HC), femur length (FL), abdominal circumference (AC). In addition, TCD/AC ratio was assessed for its efficiency in diagnosing IUGR pregnancy if its value was above 95th percentile. Results: Our results showed no significant difference between the mean gestation age detected by TCD compared to the actual mean gestation age in normal as well as IUGR cases, in addition the TCD showed the highest diagnostic accuracy of 95% in detection of gestation age in IUGR within 2 weeks. TCD/AC ratio showed accuracy of 91.43% in diagnosis of IUGR if ratio above 95Th percentile. Conclusion: TCD is a very important parameter in diagnosis of IUGR cases and proper assessment of gestation age. [ABSTRACT FROM AUTHOR]

Background and Objectives: Sickle cell anemia (SCA) is associated with recurrent acute inflammatory processes. These inflammatory processes could lead to elevation of Factor VIII and Von Willebrand Factor levels, thereby increasing the risk of stroke in SCA children. This study aims to determine vWF/FVIII levels in children with SCA and their association with abnormal transcranial Doppler (TCD). Subjects and Methods: This study enrolled 75 children, including 24 SCA cases with normal TCD, 27 SCA cases with abnormal TCD, and 24 Hb AA controls, all aged between 2 and 16 years. Transcranial Doppler (TCD) ultrasound was performed to measure the cerebral blood velocity. Venous blood drawn from each participant was used to determine the levels of von Willebrand Factor Antigen (vWF: Ag) and Factor VIII (FVIII) and the complete blood count (CBC). Relationships among the measured parameters were determined using SPSS version 25. Statistical significance was set at P <.05. Results: FVIII and vWF levels were significantly higher among children with SCA compared to the Hb AA controls (P <.001). Although SCA patients with abnormal TCD tended to have higher levels of FVIII and vWF, this result did not attain statistical significance (P >.05). There was a moderate negative correlation between the left middle cerebral artery and FVIII, (r = −0.332; P =.017). Children with SCA showing an abnormal TCD velocity had significantly higher platelet count compared to those with normal TCD (P =.018). Conclusion: Children with SCA have elevated levels of FVIII and vWF, and an abnormal TCD velocity is associated with elevated platelet count. [ABSTRACT FROM AUTHOR]

Today, it seems prudent to reconsider how ultrasound technology can be used for providing intraoperative neurophysiologic monitoring that will result in better patient outcomes and decreased length and cost of hospitalization. An extensive and rapidly growing literature suggests that the essential hemodynamic information provided by transcranial Doppler (TCD) ultrasonography neuromonitoring (TCDNM) would provide effective monitoring modality for improving outcomes after different types of vascular, neurosurgical, orthopedic, cardiovascular, and cardiothoracic surgeries and some endovascular interventional or diagnostic procedures, like cardiac catheterization or cerebral angiography. Understanding, avoiding, and preventing peri‐ or postoperative complications, including neurological deficits following abovementioned surgeries, endovascular intervention, or diagnostic procedures, represents an area of great public and economic benefit for society, especially considering the aging population. The American Society of Neurophysiologic Monitoring and American Society of Neuroimaging Guidelines Committees formed a joint task force and developed updated guidelines to assist in the use of TCDNM in the surgical and intensive care settings. Specifically, these guidelines define (1) the objectives of TCD monitoring; (2) the responsibilities and behaviors of the neurosonographer during monitoring; (3) instrumentation and acquisition parameters; (4) safety considerations; (5) contemporary rationale for TCDNM; (6) TCDNM perspectives; and (7) major recommendations. [ABSTRACT FROM AUTHOR]

A novel micro-thermal conductivity detector with a semi-diffusion gas channel is demonstrated. This semi-diffusion channel can reduce the flow-rate interference significantly by lowering the gas flow velocity above the hot film and maintains fast response speed at the same time. Simulations indicate that the semi-diffusion type with triangular shape has the best flow-insensitive effect. When the temperature of the hot film is about 500 K, the maximal temperature deviation of the hot film caused by flow rate change in this case can be decreased by 82.4% compared with the traditional straight type. Experiments are carried under the conditions of sample and carrier gas commonly used in gas chromatograph (GC), which is achieved by using He and CO2. With the sample gas flow ranging from 1 to 20 sccm, the voltage deviation in the semi-diffusion type is reduced for as much as 85.1% of that in the straight type. This effect is also verified in binary gases with various thermal conductivities. In addition, the recovery time of the semi-diffusion design is almost the same as the straight type, less than 170 ms, indicating it is suitable for the rapid gas detection in GC. [ABSTRACT FROM AUTHOR]

Sickle cell anemia (SCA) is a genetic disorder characterized by the production of abnormal hemoglobin S, leading to red blood cell sickling and subsequent vaso-occlusive events. Neurological complications, particularly strokes, significantly contribute to the morbidity and mortality associated with SCA. While ischemic strokes are more common, hemorrhagic strokes, though less frequent, present significant challenges, especially in the pediatric population. Understanding the complex interplay of genetic, environmental, and hematological factors is crucial for managing these cases. We report two cases of pediatric patients with SCA who experienced rare hemorrhagic strokes. The first case involves a nine-year-old male presenting with a subarachnoid hemorrhage, revealing cortical ischemia and multiple cerebral artery strictures. Early supportive measures resulted in a good clinical improvement, after which the patient underwent bone marrow transplantation. The second case describes a seven-year-old male who developed an epidural hematoma during a vaso-occlusive crisis, necessitating emergency surgical intervention. After initial persistent neurological deficits, the patient began to show gradual improvement with ongoing management, reflecting the complexity and severity of such events. Hemorrhagic strokes in pediatric SCA patients, though rare, represent significant clinical challenges due to their multifactorial etiology and complex management needs. These cases underscore the importance of a multidisciplinary approach and advanced diagnostic tools in managing hemorrhagic complications in SCA. Further research is essential to unravel the pathophysiological mechanisms and develop targeted prevention strategies to improve outcomes for this vulnerable population., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Research and Ethical Committee, King Salman Armed Forces Hospital issued approval KSAFH-REC-2024-593. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Mustafa et al.)

Objective: This study aims to compare the diagnostic efficacy of somatosensory-evoked potentials (SEPs) and transcranial Doppler sonography (TCD) for monitoring cerebral tissue ischemia during carotid endarterectomy (CEA) using network meta-analysis and retrospective analysis of clinical data., Methods: For the meta-analysis, we conducted a comprehensive search of 4 electronic databases (PubMed, EMBASE, Cochrane, and Web of Science) from inception to September 2023, resulting in the inclusion of 52 relevant articles. Additionally, a retrospective study was conducted at our hospital, involving patients who underwent CEA surgery from July 2019 to July 2021., Results: The network meta-analysis incorporated 52 articles, with ranking results indicating that SEP demonstrated superior performance in specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy with surface under the cumulative ranking curve values of 99.9%, 93.8%, 96.6%, and 99.9%, respectively. Furthermore, TCD exhibited the highest sensitivity with a surface under the cumulative ranking value of 92.0%. A total of 190 patients meeting inclusion criteria were included in the retrospective study. The area under the curve for SEP's receiver operating characteristic curve was 0.787, compared to TCD's area under the curve of 0.606. SEP demonstrated a sensitivity of 66.67%, with a specificity of 90.76%, PPV of 19.05%, NPV of 98.82%, and accuracy of 90%. For TCD, the diagnostic performance measures included a sensitivity of 50.00%, specificity of 71.19%, PPV of 5.35%, NPV of 97.76%, and accuracy of 70.53%. The Fisher's exact test for sensitivity yielded a result of P = 1.000. The χˆ2 test for specificity resulted in χˆ2 = 22.863, with P < 0.001. Continuous correction χˆ2 tests for PPV and NPV showed χˆ2 = 2.005 (P = 0.157) and χˆ2 = 0.069 (P = 0.793), respectively. Additionally, the χˆ2 test for accuracy showed χˆ2 = 22.742, with P < 0.001., Conclusions: During CEA, SEP appears to provide a slightly more reliable indication of the ischemic condition in cerebral tissues compared to TCD., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Even though stroke is rare in children, it is associated with serious or life-threatening consequences. Despite its rarity, the occurrence of stroke in children has age-related differences in risk factors, etiopathogenesis, and clinical presentations. Unlike adults, who have arteriosclerosis as the major cause of stroke, risk factors for pediatric strokes are multiple, including cardiac disorders, infection, prothrombotic disorders, moyamoya disease, moyamoya syndrome, and others. The goal of the current study was to compare the characteristics, clinical features, etiology, subtypes, and workup of pediatric and adult strokes. Methods: This was a hospital-based observational study conducted on 222 participants. All patients underwent a full clinical and neurological examination, full laboratory study, cardiac evaluation, and neuroimaging; CT scan, MRI, MRA, MRV, carotid duplex, and transcranial Doppler (TCD). Ischemic stroke (IS) etiology was classified according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria, the "proposed classification for subtypes of arterial ischemic stroke in children," and the Oxfordshire Community Stroke Project (OCSP). Stroke severity was determined by the National Institutes of Health Stroke Scale (NIHSS) and PedNIHSS on admission. Results: The proportion of pediatric ischemic strokes in the current study was 63.4 percent, while hemorrhagic strokes were 36.5%. The majority of the adult patients had ischemic strokes (84.1%), while hemorrhagic strokes were noted in 15.8% of the patients. According to the original TOAST classification, in the current study, the etiology of pediatric IS was other determined causes in 63.6%, undetermined etiology in 27.2%, and cardioembolic in 9.0%. For the adult group, the major stroke subtypes were large artery disease, small vessel disease, cardioembolic, other determined causes, and undetermined etiology at 49.6%, 28.6%, 6.9%, 0.6%, and 12.5%, respectively. Conclusions: There is a greater etiological role for non-atherosclerotic arteriopathies, coagulopathies, and hematological disorders in pediatric stroke, while adults have more atherothrombotic causes. The co-existence of multiple risk factors in pediatric ischemic stroke is noticed. Thrombophilia evaluation is helpful in every case of childhood stroke. Children who have had a stroke should undergo vascular imaging as soon as possible. Imaging modalities include TCD and Doppler ultrasound, CT, MRI, MRA, and MRV, and cerebral angiography. [ABSTRACT FROM AUTHOR]

Abstract Background Cerebral stroke is a major source of mortality and morbidity. Duplex ultrasonography is used to evaluate carotid and cerebral arteries. The objectives of this work are to study the correlation between carotid duplex parameters with risk factors of ischemic stroke and evaluate duplex parameter as prognostic tool of ischemic stroke. Methods The study was conducted on 100 patients presented by acute ischemic stroke submitted to history taking, medical, and neurological examination. Neurological deficit was assessed by National Institute of Health Stroke Scale (NIHSS); the functional state of the patients was assessed by modified Rankin scale (mRS). Brain CT and/or MRI, routine laboratory investigations, extracranial, and transcranial duplex (TCD) were done. Results The end diastolic velocities (EDVs) and peak systolic velocities (PSVs) of common carotid arteries (CCA) were significantly decreased in smokers and hypertensive (P

Hypnotizability is a cognitive trait associated with differences in the brachial artery flow-mediated dilatation of individuals with high hypnotizability (highs) and low hypnotizability scores (lows). The study investigated possible hypnotizability-related cerebrovascular differences. Among 24 healthy volunteers, the Stanford Hypnotic Susceptibility Scale Form A identified 13 medium-to-lows (med-lows), 11 medium-to-highs (med-highs), and 1 medium hypnotizable. Hypnotizability did not influence the significant changes produced by the trail making task (TMT), mental arithmetic task (MAT), hyperventilation (HVT), and rebreathing (RBT) on heart rate (HR), arterial blood pressure (ABP), and partial pressure of end-tidal CO2 (PETCO2), but moderated the correlations between the changes occurring during tasks with respect to basal conditions (Δ) in ABP and PETCO2 with middle cerebral artery flow velocity (MCAv). In HVT, med-lows exhibited a significant correlation between ΔMCAv and ΔPETCO2, and med-highs showed a significant correlation between ΔABP and ΔMCAv. Cerebrovascular reactivity (CVR) and conductance (ΔCVCi) were significantly correlated with ΔMCAv only in med-lows during HVT and RBT. For the first time, cerebrovascular reactivity related to hypnotizability was investigated, evidencing different correlations among hemodynamic variables in med-highs and med-lows. [ABSTRACT FROM AUTHOR]

Imaging techniques including transcranial Doppler (TCD), magnetic resonance imaging (MRI), computed tomography (CT), and cerebral angiography are available for cerebrovascular disease diagnosis. TCD is a less expensive, non-invasive, and practically simpler approach to diagnosing cerebrovascular disorders than the others. TCD is a commonly available and inexpensive diagnostic tool. However, owing to its large operator dependency, it has a narrow application area. Cerebrovascular disease indicates a group of disorders that alter the flow of blood in the brain. The brain's functions can be temporarily or permanently impaired as a result of this change in blood flow. Timely diagnosis and treatment can restore the brain-impaired functions, resulting in a much-improved prognosis for the patients. This review summarizes the basic principles underlying the TCD imaging technique and its utility as a diagnostic tool for cerebrovascular disease. [ABSTRACT FROM AUTHOR]

The Ni/MgO catalysts were synthesized by hydrothermal method and the effect of changes in nickel ratio on the physicochemical properties and catalytic performance were investigated for TCD of CH 4 to H 2. In all catalysts, the only NiO–MgO phase as solid solution was formed, and crystals size were in the nanoparticles range. The results confirmed that the catalysts with mesoporous structure and high porosity were successfully synthesized by one step in the absence of surfactants. The increasing nickel ratio from 10 to 40 wt% increases the methane conversion from 28.3 to 48.6% and hydrogen yield from 33.2 to 53.2%, respectively. Also, the stability of catalysts depends on the amount and size of nickel particles in the structure of the catalysts. Among the catalysts, 40 and 30 wt% showed the highest initial activity (48.6% methane conversion) and the highest stability (above 45% hydrogen yield for 180 min), respectively. [Display omitted] • Preparation of Ni/MgO nano catalyst by facile one-step hydrothermal method. • Application of Ni/MgO nano catalyst for TCD of CH 4 to with high activity. • Achievement of high activity (48.6% conversion) and stability (45% yield). [ABSTRACT FROM AUTHOR]

Background and Purpose: Leukoaraiosis is thought to be related to long-standing microvascular ischemia. The pathogenic mechanisms and hemodynamic changes could be different for periventricular and deep white matter leukoaraiosis. In this cross-sectional study, we examined whether the Pulsatility Index (PI) in Transcranial Doppler ultrasonography (TCD), which can give indirect information regarding downstream microvascular resistance and compliance, is different for leukoaraiosis in periventricular and deep locations. Correlation between presence of leukoaraiosis and PI was also studied since it was not studied in South-Asian patients before.Methods: Consecutive patients with suspected lacunar stroke or white-matter disease, undergoing MR brain imaging were included. Vascular imaging was done with CT or MR Angiography to rule out significant (>50%) stenosis. Fazeka's grading was done for severity of leukoaraiosis and mean PI in the middle cerebral artery (MCA) was obtained with trans-temporal TCD.Results: Ninety patients (Mean age 61 ± 10.9 years, 29% females) were available for final analysis. Age, hypertension, diabetes mellitus, CAD, and presence of leukoaraiosis were strongly associated with elevated mean PI in univariate analysis. In multivariate analysis, presence of leukoaraiosis was significantly associated with higher mean PI after adjusting for other variables. Mean PI strongly correlated with both periventricular (Spearman's correlation coefficient 0.56, P = 0.01) and deep white matter (Spearman's correlation coefficient 0.63, P = 0.01) leukoaraiosis.Conclusions: Our study confirms the correlation of Pulsatility Index with leukoaraiosis in South-Asian patients. Interestingly, changes in microvascular resistance appeared to be similar for both periventricular and deep white matter leukoaraiosis in spite of potential differences in etiopathogenesis. [ABSTRACT FROM AUTHOR]

Abstract Background Idiopathic intracranial hypertension (IIH) is a disorder of increased intracranial pressure without a clear cause and can have serious visual effects. Previous research work suggests that transcranial Doppler measurements of pulsatility index correlate accurately with elevated intracranial pressure. Objective To assess the cerebrovascular hemodynamic changes in patients with IIH using transcranial Doppler before and after lumbar puncture and CSF withdrawal. Methods An interventional study conducted on 40 patients (31 females and 9 males) fulfilling the modified Dandy criteria for diagnosis of idiopathic intracranial hypertension, MRI brain, and MRV was done to the patients. Lumbar puncture was done for all included patients to measure intracranial pressure and CSF withdrawal. Transcranial Doppler was performed for all included before and after lumbar puncture and CSF withdrawal and the following parameters were measured: peak systolic velocity (PSV), end diastolic velocity (EDV), resistivity index (RI), and pulsatility index (PI). Results Significant relation was found between grades of papilledema and PSV, RI, and PI (p value 0.012, 0.025, 0.016) but no significant relation was found between grades of papilledema and EDV (0.102). Significant changes occurred in parameters of TCD pre- and post-CSF withdrawal including PSV, EDV, and PI (p value 0.001, 0.015, 0.019) denoting a significant change in cerebral hemodynamics after CSF withdrawal which denotes a decrease in intracranial pressure. Conclusion Increased intracranial pressure significantly affects cerebral blood flow. A normalization of transcranial Doppler parameters occurs following lowering of intracranial pressure through lumbar puncture and CSF withdrawal.

Imaging techniques including transcranial Doppler (TCD), magnetic resonance imaging (MRI), computed tomography (CT), and cerebral angiography are available for cerebrovascular disease diagnosis. TCD is a less expensive, non-invasive, and practically simpler approach to diagnosing cerebrovascular disorders than the others. TCD is a commonly available and inexpensive diagnostic tool. However, owing to its large operator dependency, it has a narrow application area. Cerebrovascular disease indicates a group of disorders that alter the flow of blood in the brain. The brain’s functions can be temporarily or permanently impaired as a result of this change in blood flow. Timely diagnosis and treatment can restore the brain-impaired functions, resulting in a much-improved prognosis for the patients. This review summarizes the basic principles underlying the TCD imaging technique and its utility as a diagnostic tool for cerebrovascular disease.

Background In obstetrics, accurately determining gestational age (GA) is a critical aspect of managing pregnancy and evaluating fetal growth and development. Intrauterine growth restriction (IUGR) is characterized by the failure of the fetus to reach its potential growth. Early detection of IUGR is crucial for optimal obstetric care to reduce fetal complications and neonatal morbidity and mortality. The purpose of the current research is to determine the role of transcerebellar diameter (TCD) and the TCD/abdominal circumference (AC) ratio in assessing fetal growth and diagnosing IUGR. Methods In the sample, there were 600 expectant mothers with GA exceeding 28 weeks. We measured TCD and AC and then calculated the TCD/AC ratio. We used IBM SPSS Statistics for Windows, V. 22.0 (IBM Corp., Armonk, NY), for statistical analysis. The data was subjected to statistical tests, including Pearson's correlation coefficient, coefficient of determination, and tests of validity. Results The current research demonstrates a strong linear correlation between TCD and GA. Additionally, there was no notable disparity in TCD measurements between normal and IUGR fetuses with the same GA. There was an insignificant relationship between the TCD/AC ratio and GA, with a constant TCD/AC ratio in the third trimester of pregnancy in normal fetuses. The mean TCD/AC ratio was 14.72±0.89 (mean±standard deviation), and a cut-off value of 16.5 was determined to diagnose IUGR. Conclusion TCD can serve as a reliable measure for GA estimation during the third trimester in pregnant women with uncertain last menstrual period (LMP) or no dating scan and IUGR fetuses. In diagnosing IUGR, the TCD/AC ratio has demonstrated greater sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The TCD/AC ratio is a GA-independent measure that can be used to diagnose IUGR., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Institutional Review Board and Ethics Committee (IRBEC) of Bangalore Baptist Hospital issued approval IRBEC/BBH/108. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Anil Kumar et al.)

For patients with symptomatic unilateral internal carotid artery (ICA) occlusion, impaired cerebrovascular reactivity (CVR) indicates increased stroke risk. Here, the role of collateral activation remains a matter of debate, whereas angio-anatomical collateral abundancy does not necessarily imply sufficient compensatory flow provided. We aimed to further elucidate the role of collateral activation in the presence of impaired CVR. From a prospective database, 62 patients with symptomatic unilateral ICA occlusion underwent blood oxygenation-level dependent (BOLD) fMRI CVR imaging and a transcranial Doppler (TCD) investigation for primary and secondary collateral activation. Descriptive statistic and multivariate analysis were used to evaluate the relationship between BOLD-CVR values and collateral activation. Patients with activated secondary collaterals exhibited more impaired BOLD-CVR values of the ipsilateral hemisphere (p = 0.02). Specifically, activation of leptomeningeal collaterals showed severely impaired ipsilateral hemisphere BOLD-CVR values when compared to activation of ophthalmic collaterals (0.05 ± 0.09 vs. 0.12 ± 0.04, p = 0.005). Moreover, the prediction analysis showed leptomeningeal collateral activation as a strong independent predictor for ipsilateral hemispheric BOLD-CVR. In our study, ipsilateral leptomeningeal collateral activation is the sole collateral pathway associated with severely impaired BOLD-CVR in patients with symptomatic unilateral ICA occlusion. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to evaluate the effect of blood pressure (BP) management with transcranial Doppler (TCD) guidance in patients with large-vessel occlusion in the anterior circulation after endovascular thrombectomy (EVT) on the long-term prognosis. Methods: This was a prospective study; 232 patients were nonrandomized assigned to TCD-guided BP management (TBM) group or non-TCD-guided BP management (NBM) group. In the TBM group, BP was controlled according to TCD showing cerebral blood flow fluctuation. In the NBM group, BP was controlled according to the guidelines. The primary endpoint was a modified Rankin scale (mRS) score of 2 or lower at 90 days. The safety outcomes were the rates of symptomatic or any intracerebral hemorrhage (ICH) and mortality at 90 days. Results: One hundred sixty-three patients were assigned to the TBM group, and 69 were assigned to the NBM group. In the propensity score-matched cohort (65 matches in both groups), there was significant difference in the proportion of participants with mRS 0–2 at 90 days according to BP management (adjusted odds ratio 3.34, 95% CI 1.36 to 8.22). There was no difference in the rates of symptomatic or any ICH and mortality between two groups. In inverse probability-weighted regression adjustment analysis, mortality decreased significantly in the TBM group than in the NBM group (adjusted odds ratio 0.86, 95% CI 0.76–0.99, p = 0.03). Conclusion: In patients with acute ischemic stroke from large-vessel occlusion in the anterior circulation, BP management under TCD was superior to NBM in improving the clinical outcomes at 90 days. Clinical Trial Registration: (URL: https://www.chictr.org.cn/showproj.aspx?proj=55484; Identifier: ChiCTR2000034443. [ABSTRACT FROM AUTHOR]

Introduction: The relationship between embolic stroke and patent foramen ovale (PFO) is well‐established. Our objective was to evaluate the association between high intensity transient signals (HITS) in contrast‐enhanced transcranial doppler ultrasonography (ceTCD), baseline MRI brain small vessel ischemic changes, and rates of acute ischemic stroke in the setting of focal neurological deficits. Methods: Electronic medical records of subjects with acute onset neurological symptoms who had ceTCD and MRI brain were evaluated. Subjects without a reported Spencer grade and/or MRI brain without available DWI and FLAIR sequences were excluded. Acute stroke rates and baseline Fazekas score in low‐grade (Spencer grade 1–2) and high‐grade (Spender grade 3–5) shunts were analyzed using Z score for 2 population proportions and Mann‐Whitney U test, respectively. Social Science Statistics was used for data analysis. Results: From June 2016 to August 2021, of 7,498 consecutive ischemic stroke patients, 132 patients were identified as possible strokes related to PFO and were hospitalized with focal neurological deficit, underwent ceTCD and MRI brain. Acute stroke was confirmed on DWI in 60% of Spencer grade 1 (n = 73), 72.2% of grade 2 (n = 19), 72.7% of grade 3 (n = 29), and 80% of grades 4 and 5 shunts (n = 11). Acute stroke rates between low grade (grades 1–2) and high grade shunts (grades 3–5), did not reach statistical significance (z = ‐0.9181; p = 0.17879). There was no significant difference in periventricular white matter disease (z = 0.85697; p = 0.19489). Fazekas scores assessing deep white matter disease were statistically significant between low‐ and high‐grade shunts (z = 1.92818; p = 0.0268 Conclusions: A trend towards statistical significance was observed in high‐grade shunt association with higher rate of acute stroke. Deep white matter disease burden may be significantly higher in high‐grade shunts. Further prospective studies are needed to corroborate our findings.

Introduction: Right‐to‐left (RtL) intracardiac and intrapulmonary shunts are associated with embolic stroke. Although contrast‐enhanced transcranial doppler ultrasonography (ceTCD) and transesophageal echocardiography (TEE) are used in embolic stroke work up, there are no standardized guidelines as to which test should be considered as ‘gold standard’. Our objective is to evaluate the sensitivity of contrast‐enhanced TCD and TEE in detecting right‐to‐left shunt to determine respective utilities as screening tools. Methods: Electronic medical records of subjects presenting with acute neurological symptoms who had ceTCD and TEE were evaluated. Sensitivity and specificity were calculated. Based on the respective prevalence of intracardiac and intrapulmonary shunts, positive predictive value, negative predictive value, and test accuracy were determined for ceTCD and TEE. Social Science Statistics was used for data analysis. Results: From June 2016 to August 2021, of 7,498 ischemic stroke patients, 260 patients were suspected of having strokes related to right to left shunts and underwent ceTCD and TEE for detection of cardioembolic sources for stroke. A positive right‐to‐left shunt was detected in 83 subjects. Detection by ceTCD was confirmed by the operator for 81 patients while 2 were considered false positive results (delayed sporadic High Intensity Transient Signals (HITS)). Sensitivity of ceTCD was 97.65% (95% CI [91.76%, 99.71%]). No safety concerns were identified in patients undergoing ceTCD. Of those with positive ceTCD (68.57%, n = 35) were detected by Valsalva, and all of those 35 patients had negative TEE. TEE had sensitivity of 70.34% (95% CI [61.23%, 78.39%]). Conclusions: Contrast‐enhanced TCD has superior sensitivity, is cost‐effective, practical, and a safe alternative to TEE in identifying intracardiac or intrapulmonary shunts. Screening superiority of ceTCD may lie in ability to elicit shunts during Valsalva maneuvers. To our knowledge this is the largest single center series confirming ceTCD as a gold standard tool for screening of right to left shunts.

Objective: The objective of this study was to evaluate the effect of blood pressure (BP) management with transcranial Doppler (TCD) guidance in patients with large-vessel occlusion in the anterior circulation after endovascular thrombectomy (EVT) on the long-term prognosis.Methods: This was a prospective study; 232 patients were nonrandomized assigned to TCD-guided BP management (TBM) group or non-TCD-guided BP management (NBM) group. In the TBM group, BP was controlled according to TCD showing cerebral blood flow fluctuation. In the NBM group, BP was controlled according to the guidelines. The primary endpoint was a modified Rankin scale (mRS) score of 2 or lower at 90 days. The safety outcomes were the rates of symptomatic or any intracerebral hemorrhage (ICH) and mortality at 90 days.Results: One hundred sixty-three patients were assigned to the TBM group, and 69 were assigned to the NBM group. In the propensity score-matched cohort (65 matches in both groups), there was significant difference in the proportion of participants with mRS 0–2 at 90 days according to BP management (adjusted odds ratio 3.34, 95% CI 1.36 to 8.22). There was no difference in the rates of symptomatic or any ICH and mortality between two groups. In inverse probability-weighted regression adjustment analysis, mortality decreased significantly in the TBM group than in the NBM group (adjusted odds ratio 0.86, 95% CI 0.76–0.99, p = 0.03).Conclusion: In patients with acute ischemic stroke from large-vessel occlusion in the anterior circulation, BP management under TCD was superior to NBM in improving the clinical outcomes at 90 days.Clinical Trial Registration: (URL: https://www.chictr.org.cn/showproj.aspx?proj=55484; Identifier: ChiCTR2000034443.

Purpose of Review: The purpose of this paper is to provide an overview of the utility and indications of sonography in the Neuro ICU, with focus on recent studies and advances. Recent Findings: Emerging data continue to shed light on the benefit of critical care sonography with neurovascular ultrasound being of particular interest in the Neuro ICU. Recent development of safe and feasible robotic TCDs holds promise in allowing continuous bedside monitoring of cerebrovascular hemodynamics, especially in conjunction with the use of automated software such as ICM+. Although newer and feasible methods for non-invasive measures of intracranial fluid and hemodynamics are rapidly emerging, use of neurovascular ultrasound remains limited due to lack of clinical and technical expertise. Recently published consensus statement on the recommended skills and competence level required to perform brain ultrasonography in the critical care setting may serve as a helpful framework to guide further training and protocol development. Summary: Utilization of systemic sonography has grown as a diagnostic and procedural aid in the critical care setting, while the rising body of literature continues to demonstrate the value of routine use of neurovascular ultrasound. Standardization of protocols and training paradigms could promote integration of this valuable tool in guiding management of brain injury patients. [ABSTRACT FROM AUTHOR]

Background: Cerebral stroke is a major source of mortality and morbidity. Duplex ultrasonography is used to evaluate carotid and cerebral arteries. The objectives of this work are to study the correlation between carotid duplex parameters with risk factors of ischemic stroke and evaluate duplex parameter as prognostic tool of ischemic stroke. Methods: The study was conducted on 100 patients presented by acute ischemic stroke submitted to history taking, medical, and neurological examination. Neurological deficit was assessed by National Institute of Health Stroke Scale (NIHSS); the functional state of the patients was assessed by modified Rankin scale (mRS). Brain CT and/or MRI, routine laboratory investigations, extracranial, and transcranial duplex (TCD) were done. Results: The end diastolic velocities (EDVs) and peak systolic velocities (PSVs) of common carotid arteries (CCA) were significantly decreased in smokers and hypertensive (P<0.05). Smoking and hypertension were positively correlated with resistive index (RI). In 80 patients, PSV in the symptomatic middle cerebral artery (MCA) did not exceed 70 cm/s within averaged 50.7 ± 4.6 cm/s. EDV was 12.0 ± 3.0 cm/s, RI was 0.78 ± 0.05, and pulsativity index (PI) was 1.61 ± 0.09. There was significant difference in all hemodynamic parameters in comparison with the asymptomatic side. Conclusion: Patients who have risk factors of stroke should be evaluated with duplex ultrasonography. Duplex parameters can give informative data about prognosis and outcome. [ABSTRACT FROM AUTHOR]

Cold Expansion (CE) techniques are extensively used in the aeronautical industry to enhance the fatigue life of open-hole plates. However, the availability of accurate Finite Element (FE) models to simulate the fatigue behavior of this process, particularly Dynamic Cold Expansion (DCE), is limited. This study introduces two novel methods for predicting the fatigue response of DCE and Static Cold Expansion (SCE) open-hole plates. The first method directly estimates the total fatigue life using Continuum Damage Mechanics (CDM) and the Theory of Critical Distance (TCD). The second method separates the prediction of fatigue crack initiation life and propagation life, incorporating CDM, TCD, and the Extended Finite Element Method (XFEM). Moreover, FE models are developed to simulate residual stress, stress under external cyclic loads, and fatigue crack propagation behavior for both DCE and SCE specimens. The proposed methods are evaluated, compared, and the mechanisms behind fatigue life enhancement and fatigue crack propagation modes in CE specimens are discussed. It is found that the prediction accuracy is enhanced by considering stress distributions along the thickness direction and improving the Line Method (LM) in TCD through the introduction of a novel CE parameter. The results demonstrate that both methods achieve good predictive performance, with an average error index within ±30%. Furthermore, it is observed that both DCE and SCE processes primarily improve the fatigue crack initiation life of open-hole plates, with the percentage of crack initiation fatigue life increasing as the expansion size increases. The majority of the fatigue crack propagation life in CE specimens is concentrated in the initial stages of crack propagation. In addition, the effects of DCE and SCE processes on reducing the fatigue crack propagation rate are more pronounced along the thickness direction compared to the width direction, leading to distinct crack propagation modes between CE and non-cold expansion (NCE) specimens. • Proposed numerical methods (CDM, TCD, XFEM) accurately predict CE open-hole plate fatigue behaviours. • CE process extends both initiation and propagation lifetimes, with more effect on initiation. • CE process reduces fatigue crack propagation rate along thickness more than width, causing different responses. • Compressive residual stress induced by CE processes initially decreases crack propagation rate. • CE specimens show good agreement with experimental data, indicating the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

Continuous cerebrovascular reactivity assessment in traumatic brain injury (TBI) has been limited by the need for invasive monitoring of either cerebral physiology or arterial blood pressure (ABP). This restricts the application of continuous measures to the acute phase of care, typically in the intensive care unit. It remains unknown if ongoing impairment of cerebrovascular reactivity occurs in the subacute and long-term phase, and if it drives ongoing morbidity in TBI. We describe an entirely non-invasive method for continuous assessment of cerebrovascular reactivity. We describe the technique for entirely non-invasive continuous assessment of cerebrovascular reactivity utilizing near-infrared spectroscopy (NIRS) and robotic transcranial Doppler (rTCD) technology, with details provided for NIRS. Recent advances in continuous high-frequency non-invasive ABP measurement, combined with NIRS or rTCD, can be employed to derive continuous and entirely non-invasive cerebrovascular reactivity metrics. Such non-invasive measures can be obtained during any aspect of patient care post-TBI, and even during outpatient follow-up, avoiding classical intermittent techniques and costly neuroimaging based metrics obtained only at specialized centers. This combination of technology and signal analytic techniques creates avenues for future investigation of the long-term consequences of cerebrovascular reactivity, integrating high-frequency non-invasive cerebral physiology, neuroimaging, proteomics and clinical phenotype at various stages post-injury. [ABSTRACT FROM AUTHOR]

Ultraviolet treatment (UV-C) is well known for its antimicrobial effects and current research shows that it has the potential to inactivate microorganisms in milk at much lower temperatures than conventional thermal treatment. However, Ultraviolet irradiation may result in adverse effects on milk quality, which arises due to photo oxidation in the presence of oxygen. Limiting the dissolved oxygen content in milk can minimize oxidative damage and thus, result in a better product quality. Nitrogen purging could be an effective method for reducing dissolved oxygen from liquids. The present study evaluates effects of nitrogen purging (prior to UV treatment) on milk quality. It was found that nitrogen purged UV treated milk causes minimal changes to physicochemical properties of milk. [ABSTRACT FROM AUTHOR]

Introduction: Emergency care delivery to patients in remote and rural areas is limited by diagnostic restrictions and long transport times to major centres of care. People with suspected acute stroke living long distances from a hospital are unlikely to receive time-critical reperfusion therapy for these reasons. Basic brain imaging assessing blood flow in the major intracranial arteries could facilitate such care in remote settings. A 3-hour training package for novice transcranial ultrasound users has been piloted on a small group of volunteers to investigate whether they could acquire transcranial ultrasound images and video clips to potentially allow remote interpretation and optimise pre-hospital management of acute stroke. Methods: A pilot training project was set up in a university setting in Inverness, Scotland. Volunteer clinicians and students of nursing or medicine with no practical experience in transcranial ultrasound were recruited. Participants received three 1-hour training sessions combining theoretical aspects and hands-on practice on healthy volunteers provided by a qualified neurologist with more than 2 years of experience in transcranial ultrasound. Transcranial greyscale and colour-coded duplex sonography was performed to visualise midline structures and major intracranial vessels, and to measure blood flow velocity in the middle cerebral artery, followed by an unsupervised assessment. Qualitative analysis of the anonymised feedback from participants on the training experience and its potential application was also performed. Results: A total of 11 volunteers were recruited in the current pilot study. The average time to complete transcranial ultrasound assessment was approximately 40 minutes. The brain midline and cerebral peduncles were correctly labelled by 64% (7/11) and 91% (10/11) of volunteers, respectively. Participants demonstrated a good performance in detecting major intracranial vessels. The correct labelling rate for the middle cerebral artery was 73% (8/11), and 64% (7/11) for the anterior and posterior cerebral arteries. There was agreement between the trainer and the participants on rating the quality of scans as assessed using a visual analogue scale. All participants gave positive feedback on the provided training and time allocated for each session. Generally, volunteers thought that operating the ultrasound machine and the probe simultaneously was difficult. It was also suggested that further follow-up training, with possible supervision, would be useful to retain the acquired skills. Conclusions: Transcranial ultrasound scans of a quality to allow expert interpretation can be acquired by inexperienced transcranial ultrasound operators after receiving a brief training. This could potentially be used by medical staff working in remote and rural areas to facilitate acute care for stroke patients, but further work with a larger sample is needed.

Introduction: Sensitisation of the nervous system in a patient with migraine is supposed to be associated with calcitonin gene-related peptide (CGRP) activity. Therefore, the vascular response to human αCGRP (hαCGRP) could be a surrogate marker for the sensitization. We hypothesize that vascular response to hαCGRP is augmented in a patient with migraine.Methods: Twenty healthy subjects and 20 patients with migraine participated in our study. TCD was used to monitor mean arterial velocity in the middle cerebral artery (vm MCA). Simultaneously, end-tidal CO2 (Et-CO2), mean arterial pressure (MAP), and heart rate (HR) were measured. The reconstruction of the signals was made for basal conditions, during and after CGRP infusion which were compared using statistics.Results: In both groups, we found significant decrease between measurement points of vm MCA and Et-CO2 during and after hαCGRP infusion. MAP did not show significant trends during the infusion, but it was significantly increased after the infusion in migraine patients only. Responses to hαCGRP, defined as differences between two measurement points, were significantly higher for vm MCA and Et-CO2 in patients with migraine. A significant difference between groups was found in MAP response. Significant relationships were found between migraine and vm MCA, Et-CO2, and MAP.Conclusion: In patients with migraine, vm MCA responses to hαCGRP are significantly higher and are associated with CGRP-induced headache which indicates that patients with migraine are more prone to sensitization.

Hypnotizability is a cognitive trait associated with differences in the brachial artery flow-mediated dilatation of individuals with high hypnotizability (highs) and low hypnotizability scores (lows). The study investigated possible hypnotizability-related cerebrovascular differences. Among 24 healthy volunteers, the Stanford Hypnotic Susceptibility Scale Form A identified 13 medium-to-lows (med-lows), 11 medium-to-highs (med-highs), and 1 medium hypnotizable. Hypnotizability did not influence the significant changes produced by the trail making task (TMT), mental arithmetic task (MAT), hyperventilation (HVT), and rebreathing (RBT) on heart rate (HR), arterial blood pressure (ABP), and partial pressure of end-tidal CO2 (PETCO2), but moderated the correlations between the changes occurring during tasks with respect to basal conditions (Δ) in ABP and PETCO2 with middle cerebral artery flow velocity (MCAv). In HVT, med-lows exhibited a significant correlation between ΔMCAv and ΔPETCO2, and med-highs showed a significant correlation between ΔABP and ΔMCAv. Cerebrovascular reactivity (CVR) and conductance (ΔCVCi) were significantly correlated with ΔMCAv only in med-lows during HVT and RBT. For the first time, cerebrovascular reactivity related to hypnotizability was investigated, evidencing different correlations among hemodynamic variables in med-highs and med-lows.

Introduction: Sensitisation of the nervous system in a patient with migraine is supposed to be associated with calcitonin gene-related peptide (CGRP) activity. Therefore, the vascular response to human αCGRP (hαCGRP) could be a surrogate marker for the sensitization. We hypothesize that vascular response to hαCGRP is augmented in a patient with migraine. Methods: Twenty healthy subjects and 20 patients with migraine participated in our study. TCD was used to monitor mean arterial velocity in the middle cerebral artery (vm MCA). Simultaneously, end-tidal CO2 (Et-CO2), mean arterial pressure (MAP), and heart rate (HR) were measured. The reconstruction of the signals was made for basal conditions, during and after CGRP infusion which were compared using statistics. Results: In both groups, we found significant decrease between measurement points of vm MCA and Et-CO2 during and after hαCGRP infusion. MAP did not show significant trends during the infusion, but it was significantly increased after the infusion in migraine patients only. Responses to hαCGRP, defined as differences between two measurement points, were significantly higher for vm MCA and Et-CO2 in patients with migraine. A significant difference between groups was found in MAP response. Significant relationships were found between migraine and vm MCA, Et-CO2, and MAP. Conclusion: In patients with migraine, vm MCA responses to hαCGRP are significantly higher and are associated with CGRP-induced headache which indicates that patients with migraine are more prone to sensitization. [ABSTRACT FROM AUTHOR]

Introduction: Emergency care delivery to patients in remote and rural areas is limited by diagnostic restrictions and long transport times to major centres of care. People with suspected acute stroke living long distances from a hospital are unlikely to receive timecritical reperfusion therapy for these reasons. Basic brain imaging assessing blood flow in the major intracranial arteries could facilitate such care in remote settings. A 3-hour training package for novice transcranial ultrasound users has been piloted on a small group of volunteers to investigate whether they could acquire transcranial ultrasound images and video clips to potentially allow remote interpretation and optimise pre-hospital management of acute stroke. Methods: A pilot training project was set up in a university setting in Inverness, Scotland. Volunteer clinicians and students of nursing or medicine with no practical experience in transcranial ultrasound were recruited. Participants received three 1-hour training sessions combining theoretical aspects and hands-on practice on healthy volunteers provided by a qualified neurologist with more than 2 years of experience in transcranial ultrasound. Transcranial greyscale and colour-coded duplex sonography was performed to visualise midline structures and major intracranial vessels, and to measure blood flow velocity in the middle cerebral artery, followed by an unsupervised assessment. Qualitative analysis of the anonymised feedback from participants on the training experience and its potential application was also performed. Results: A total of 11 volunteers were recruited in the current pilot study. The average time to complete transcranial ultrasound assessment was approximately 40 minutes. The brain midline and cerebral peduncles were correctly labelled by 64% (7/11) and 91% (10/11) of volunteers, respectively. Participants demonstrated a good performance in detecting major intracranial vessels. The correct labelling rate for the middle cerebral artery was 73% (8/11), and 64% (7/11) for the anterior and posterior cerebral arteries. There was agreement between the trainer and the participants on rating the quality of scans as assessed using a visual analogue scale. All participants gave positive feedback on the provided training and time allocated for each session. Generally, volunteers thought that operating the ultrasound machine and the probe simultaneously was difficult. It was also suggested that further follow-up training, with possible supervision, would be useful to retain the acquired skills. Conclusions: Transcranial ultrasound scans of a quality to allow expert interpretation can be acquired by inexperienced transcranial ultrasound operators after receiving a brief training. This could potentially be used by medical staff working in remote and rural areas to facilitate acute care for stroke patients, but further work with a larger sample is needed. [ABSTRACT FROM AUTHOR]

Background: Idiopathic intracranial hypertension (IIH) is a disorder of increased intracranial pressure without a clear cause and can have serious visual effects. Previous research work suggests that transcranial Doppler measurements of pulsatility index correlate accurately with elevated intracranial pressure. Objective: To assess the cerebrovascular hemodynamic changes in patients with IIH using transcranial Doppler before and after lumbar puncture and CSF withdrawal. Methods: An interventional study conducted on 40 patients (31 females and 9 males) fulfilling the modified Dandy criteria for diagnosis of idiopathic intracranial hypertension, MRI brain, and MRV was done to the patients. Lumbar puncture was done for all included patients to measure intracranial pressure and CSF withdrawal. Transcranial Doppler was performed for all included before and after lumbar puncture and CSF withdrawal and the following parameters were measured: peak systolic velocity (PSV), end diastolic velocity (EDV), resistivity index (RI), and pulsatility index (PI). Results: Significant relation was found between grades of papilledema and PSV, RI, and PI (p value 0.012, 0.025, 0.016) but no significant relation was found between grades of papilledema and EDV (0.102). Significant changes occurred in parameters of TCD pre- and post-CSF withdrawal including PSV, EDV, and PI (p value 0.001, 0.015, 0.019) denoting a significant change in cerebral hemodynamics after CSF withdrawal which denotes a decrease in intracranial pressure. Conclusion: Increased intracranial pressure significantly affects cerebral blood flow. A normalization of transcranial Doppler parameters occurs following lowering of intracranial pressure through lumbar puncture and CSF withdrawal. [ABSTRACT FROM AUTHOR]

Background and Purpose: Intracranial atherosclerosis has gained increasing attention due to the high risk of recurrent clinical or subclinical ischemic events, while the relationship between low-density lipoprotein cholesterol (LDL-C) measured at a single time point and intracranial atherosclerotic stenosis (ICAS) is inconsistent. This study aims to assess the association between cumulative exposure to increased LDL-C and the prevalence of asymptomatic ICAS.Methods: The Asymptomatic Polyvascular Abnormalities Community study was investigated on the epidemiology of asymptomatic polyvascular abnormalities in Chinese adults. In this study, we included 4,523 participants with LDL-C measured at 3 examinations in 2006, 2008, and 2010. Cumulative exposure to increased LDL-C was calculated as following: LDL-C burden2006−2008 = [(LDL-C2006-1.8) + (LDL-C2008-1.8)]/2 * time2006−2008; LDL-C burden = LDL-C burden2006−2008 + LDL-C burden2008−2010. Transcranial doppler ultrasonography was performed in 2010 to detecting the ICAS.Results: Of the 4,347 patients, 13.3% (580/4,347) were diagnosed with ICAS. In univariate analysis, the association between LDL-C burden and ICAS prevalence was significant, the odds ratios (95% confidence interval) from the lowest to the highest quartile were 1 (reference), 1.30 (0.99–1.70), 1.32 (1.01–1.73), and 2.14 (1.66–2.75), respectively (P < 0.05). After adjustment for potential confounding factors, the same result was reached.Conclusions: Cumulative exposure to increased LDL-C is concentration-dependently associated with increased prevalence of asymptomatic ICAS, especially in those under the age of 65 y or free of hypertension, diabetes mellitus, and hyperlipidemia.

Abstract Introduction Aging is associated with impaired cerebrovascular blood flow and function, attributed to reduced vasodilatory capacity of the cerebrovascular network. Older adults may also have an impaired relationship between changes in blood pressure and cerebral blood flow; however, previous reports conflict. This study aimed to compare the blood pressure and cerebral blood flow responses to both repeated and sustained stand‐to‐sit transitions in young and older adults, and to assess the relationship with cerebrovascular reactivity. Methods In 20 young (age: 24 ± 4 years) and 20 older (age: 71 ± 7 years) adults we compared middle cerebral artery flow velocity (MCAv), end‐tidal partial pressure of carbon dioxide (PETCO2), and blood pressure (mean arterial blood pressure [MAP]) during repeated stand‐to‐sit (10 s standing and 10 s sitting) and sustained stand‐to‐sit (3 min standing followed by 2 min sitting) transitions. Cerebrovascular reactivity to changes in carbon dioxide levels was assessed using a repeated breath‐hold test. Results The % change in MCAv per % change in MAP (%∆MCAv/%∆MAP) was higher in the older adults than in the young adults during repeated stand‐to‐sit transitions. During the sustained protocol the %∆MCAv/%∆MAP response was similar in both age groups. A high %∆MCAv/%∆MAP response during the repeated stand‐to‐sit protocol was associated with low cerebrovascular reactivity to CO2 (r = −.39; p