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Neurocritical patients frequently exhibit abnormalities in cerebral hemodynamics (CH) and/or intracranial compliance (ICC), all of which significantly impact their clinical outcomes. Transcranial Doppler (TCD) and the cranial micro-deformation sensor (B4C) are valuable techniques for assessing CH and ICC, respectively. However, there is a scarcity of data regarding the predictive value of these techniques in determining patient outcomes. We prospectively included neurocritical patients undergoing intracranial pressure (ICP) monitoring within the first 5 days of hospital admission for TCD and B4C assessments. Comprehensive clinical data were collected alongside parameters obtained from TCD (including the estimated ICP [eICP] and estimated cerebral perfusion pressure [eCPP]) and B4C (measured as the P2/P1 ratio). These parameters were evaluated individually as well as in combination. The short-term outcomes (STO) of interest were the therapy intensity levels (TIL) for ICP management recommended by the Seattle International Brain Injury Consensus Conference, as TIL 0 (STO 1), TIL 1-3 (STO 2) and death (STO 3), at the seventh day after last data collection. The dataset was randomly separated in test and training samples, area under the curve (AUC) was used to represent the noninvasive techniques ability on the STO prediction and association with ICP. A total of 98 patients were included, with 67% having experienced severe traumatic brain injury and 15% subarachnoid hemorrhage, whilst the remaining patients had ischemic or hemorrhagic stroke. ICP, P2/P1, and eCPP demonstrated the highest ability to predict early mortality (p = 0.02, p = 0.02, and p = 0.006, respectively). P2/P1 was the only parameter significant for the prediction of STO 1 (p = 0.03). Combining B4C and TCD parameters, the highest AUC was 0.85 to predict death (STO 3), using P2/P1 + eCPP, whereas AUC was 0.72 to identify ICP > 20 mmHg using P2/P1 + eICP. The combined noninvasive neuromonitoring approach using eCPP and P2/P1 ratio demonstrated improved performance in predicting outcomes during the early phase after acute brain injury. The correlation with intracranial hypertension was moderate, by means of eICP and P2/P1 ratio. These results support the need for interpretation of this information in the ICU and warrant further investigations for the definition of therapy strategies using ancillary tests.

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Objective: Transcranial Doppler (TCD) and brain MRI may be useful in evaluating patients with APS, helping to stratify the risk of cerebrovascular ischaemic events in this population. This study aimed to assess the frequency of brain MRI abnormalities in patients with primary antiphospholipid syndrome, secondary antiphospholipid syndrome and SLE and correlate to TCD findings. Methods: The study, conducted over four years at two autoimmune disease referral centres, included 22 primary antiphospholipid syndrome patients, 24 secondary antiphospholipid syndrome patients, 27 SLE patients without APS and 21 healthy controls. All participants underwent TCD to assess cerebral haemodynamics, detect microembolic signals and evaluate right-to-left shunts, followed by brain MRI and magnetic resonance angiography. MRI scans were reviewed for acute microembolism, localized cortical infarctions, border infarctions, lacunar infarctions, ischaemic lesions, white matter hyperintensity, micro and macro haemorrhages and arterial stenosis ≥50% of the cervical carotid artery, by two neuroradiologists blinded to the clinical data. Results: Brain MRI findings were similar between the groups, except for lacunar infarction, more frequent in patients with secondary antiphospholipid syndrome (P = 0.022). Patients with intracranial stenosis detected by TCD had a higher frequency of territorial infarction (40% vs 7.5%, P = 0.02), lacunar (40% vs 11.3%, P = 0.075) and border zone infarcts (20% vs 1.9%, P = 0.034). Conclusions: Patients with intracranial stenosis presented a higher frequency of territorial, lacunar and border zone infarcts, suggesting that evaluating the intracranial vasculature should not be neglected in patients with APS and stroke.

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Intracranial hypertension (IH) is a life-threating condition especially for the brain injured patient. In such cases, an external ventricular drain (EVD) or an intraparenchymal bolt are the conventional gold standard for intracranial pressure (ICPi) monitoring. However, these techniques have several limitations. Therefore, identifying an ideal screening method for IH is important to avoid the unnecessary placement of ICPi and expedite its introduction in patients who require it. A potential screening tool is the ICP wave morphology (ICPW) which changes according to the intracranial volume-pressure curve. Specifically, the P2/P1 ratio of the ICPW has shown promise as a triage test to indicate normal ICP. In this study, we propose evaluating the noninvasive ICPW (nICPW-B4C sensor) as a screening method for ICPi monitoring in patients with moderate to high probability of IH. This is a retrospective analysis of a prospective, multicenter study that recruited adult patients requiring ICPi monitoring from both Federal University of São Paulo and University of São Paulo Medical School Hospitals. ICPi values and the nICPW parameters were obtained from both the invasive and the noninvasive methods simultaneously 5 min after the closure of the EVD drainage. ICP assessment was performed using a catheter inserted into the ventricle and connected to a pressure transducer and a drainage system. The B4C sensor was positioned on the patient's scalp without the need for trichotomy, surgical incision or trepanation, and the morphology of the ICP waves acquired through a strain sensor that can detect and monitor skull bone deformations caused by changes in ICP. All patients were monitored using this noninvasive system for at least 10 min per session. The area under the curve (AUC) was used to describe discriminatory power of the P2/P1 ratio for IH, with emphasis in the Negative Predictive value (NPV), based on the Youden index, and the negative likelihood ratio [LR-]. Recruitment occurred from August 2017 to March 2020. A total of 69 patients fulfilled inclusion and exclusion criteria in the two centers and a total of 111 monitorizations were performed. The mean P2/P1 ratio value in the sample was 1.12. The mean P2/P1 value in the no IH population was 1.01 meanwhile in the IH population was 1.32 (p < 0.01). The best Youden index for the mean P2/P1 ratio was with a cut-off value of 1.13 showing a sensitivity of 93%, specificity of 60%, and a NPV of 97%, as well as an AUC of 0.83 to predict IH. With the 1.13 cut-off value for P2/P1 ratio, the LR- for IH was 0.11, corresponding to a strong performance in ruling out the condition (IH), with an approximate 45% reduction in condition probability after a negative test (ICPW). To conclude, the P2/P1 ratio of the noninvasive ICP waveform showed in this study a high Negative Predictive Value and Likelihood Ratio in different acute neurological conditions to rule out IH. As a result, this parameter may be beneficial in situations where invasive methods are not feasible or unavailable and to screen high-risk patients for potential invasive ICP monitoring.Trial registration: At clinicaltrials.gov under numbers NCT05121155 (Registered 16 November 2021-retrospectively registered) and NCT03144219 (Registered 30 September 2022-retrospectively registered).

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Intracranial pressure (ICP) monitoring is necessary for managing patients with traumatic brain injury (TBI). Although gold-standard methods include intraventricular or intraparenchymal transducers, these systems cannot be used in patients with coagulopathies or in those who are at high risk of catheter-related infections, nor can they be used in resource-constrained settings. Therefore, a non-invasive modality that is more widely available, cost effective, and safe would have tremendous impact. Among such non-invasive choices, transcranial Doppler (TCD) provides indirect ICP estimates through waveform analysis of cerebral hemodynamic changes. The objective of this scoping review is to describe the existing evidence for the use of TCD-derived methods in estimating ICP in adult TBI patients as compared with gold-standard invasive methods. This review was conducted in accordance with the Joanna Briggs Institute methodology for scoping reviews, with a main search of PubMed and Embase. The search was limited to studies conducted in adult TBI patients published in any language between 2012 and 2022. Twenty-two studies were included for analysis, with most being prospective studies conducted in high-income countries. TCD-derived non-invasive ICP (nICP) methods are either mathematical or non-mathematical, with the former having slightly better correlation with invasive methods, especially when using time-trending ICP dynamics over one-time estimated values. Nevertheless, mathematical methods are associated with greater cost and complexity in their application. Formula-based methods showed promise in excluding elevated ICP, exhibiting a high negative predictive value. Therefore, TCD-derived methods could be useful in assessing ICP changes instead of absolute ICP values for high-risk patients, especially in low-resource settings.

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Brazil is a continental country with significant socioeconomic and ethnic inequalities. It is important to understand how these differences are reflected in health care, especially during the COVID-19 pandemic. We investigated the potential impacts of the reduced number Transcranial Doppler Ultrasound (TCD) tests performed in Brazil during the COVID-19 pandemic, and its reflections according to region and race/color for patients with Sickle Cell Disease (SCD). This study performed data queries from the Brazilian Ministry of Health, literature research, and quantitative analysis using descriptive statistical analysis. We found evidence for a decrease in the number of TCD tests performed during the pandemic (-83 %) relative to the same non-pandemic period, and disparities in tests given in five regions in Brazil. Our data show, that in absolute numbers, most people with SCD are brown, but the highest prevalence of cases was among blacks. We also found evidence for racial discrimination when performing TCD test, which leads us to believe that the Brazilian Unified Health System (SUS) may be susceptible to racism when treating this disease. The implications of these findings serve as a warning to other countries with high indices of mixed ancestry in formulating health care policies for patients with SCD.

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BACKGROUND: Transcranial Doppler (TCD) is a noninvasive bedside tool for cerebral hemodynamic assessments in multiple clinical scenarios. TCD, by means of measuring systolic and diastolic blood velocities, allows the calculation of the pulsatility index (PI), a parameter that is correlated with intracranial pressure (ICP). Nevertheless, the predictive value of the PI for raised ICP appears to be low, as it is subjected to several, often confounding, factors not related to ICP. Recently, the pulsatile apparent resistance (PaR) index was developed as a PI corrected for arterial blood pressure, reducing some of the confounding factors influencing PI. This study compares the predictive value of PaR versus PI for intracranial hypertension (IH) (ICP > 20 mm Hg) in patients with traumatic brain injury. METHODS: Patients with traumatic brain injury admitted to the neurocritical care unit who required invasive ICP monitoring were included prospectively within 5 days of admission. TCD measurements were performed in both middle cerebral arteries, allowing calculations of the PI and PaR. The optimal cutoff, discriminative power of these parameters for ICP ≥ 20 mm Hg, was assessed by calculating the area under the receiver operator characteristics curve (AUC). RESULTS: In total, 93 patients were included. A total of 20 (22%) patients experienced IH during the recording sessions. The discriminative power was low for PI (AUC 0.63) but slightly higher for PaR (AUC 0.77). Nonparametric analysis indicated significant difference for PaR when comparing patients with (median 0.169) and without IH (median - 0.052, p = 0.001), whereas PI medians for patients with and without IH were 0.86 and 0.77, respectively (p = 0.041). Regarding subanalyses, the discriminative power of these parameters increased after exclusion of patients who had undergone a neurosurgical procedure. This was especially true for the PaR (AUC 0.89) and PI (AUC 0.72). Among these patients, a PaR cutoff value of - 0.023 had 100% sensitivity and 52.9% specificity. CONCLUSIONS: In the present study, discriminative power of the PaR for discriminating IH was superior to the PI. The PaR seems to be a reliable noninvasive parameter for detecting IH. Further studies are warranted to define its clinical application, especially in aiding neurosurgical decision making, following up in intensive care units, and defining its ability to indicate responses according to the therapies administered.

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As the older population grows, there is an increasing interest in understanding how physical exercise can counteract the changes seen with aging. The benefits of exercise to general health, and especially to the cardiovascular system, have been a topic of discussion for decades. However, there is still a need to elucidate the effects of training programs on the cerebrovascular blood velocity in older people. This systematic review and meta-analysis aimed to investigate the effect of physical exercise on the cerebral blood velocity in older people (PROSPERO CRD42019136305). A search was performed on PubMed, Web of Science, EBSCO, ScienceDirect, and Scopus from the inception of this study to October 2023, retrieving 493 results, of which 26 were included, analyzing more than 1000 participants. An overall moderate risk of bias was found for the studies using the Cochrane risk-of-bias tools for randomized and non-randomized clinical trials. The pooled results of randomized trials showed that older people who underwent physical exercise presented a statistically significant increase in cerebral blood velocity (3.58; 95%CI = 0.51, 6.65; p = 0.02). This result indicates that physical exercise is important to help maintain cerebral health in older adults.

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The effectiveness of endovascular thrombectomy in patients presenting low National Institutes of Health Stroke Scale (NIHSS) scores remains controversial, and the acquisition of additional evidence is required to refine the selection of candidates who may benefit the most from this therapeutic modality. In this study, we present the case of a 62-year-old individual, with left internal carotid occlusion stroke and low NIHSS, who had compensatory collateral flow from Willis polygon via the anterior communicating artery. The patient subsequently exhibited neurological deterioration and collateral flow failure from Willis polygon, indicating the need for urgent intervention. The study of collaterals in patients with large vessel occlusion stroke has garnered considerable attention, with research suggesting that individuals with low NIHSS scores and poor collateral profiles may be at a heightened risk of early neurological deterioration. We postulate that such patients may derive significant benefits from endovascular thrombectomy, and may posit that an intensive transcranial Doppler monitoring protocol could facilitate the identification of suitable candidates for such intervention.

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Resumen: La estenosis carotídea (EC) ocurre en 13% de los pacientes con estenosis valvular aórtica (EVA). El riesgo de evento vascular cerebral (EVC), en los pacientes con EC significativa sometidos a cirugía valvular cardíaca, puede aumentar hasta 11%. Someter a un paciente con EVA crítica y fracción de eyección del ventrículo izquierdo (FEVI) disminuida a endarterectomía carotídea es todo un reto anestésico, cuyo principal objetivo es evitar la hipotensión y el bajo gasto cardíaco. La anestesia regional es una opción para estos pacientes. Presentamos el caso de un hombre de 70 años con diagnóstico de EC significativa y EVA crítica con disfunción ventricular izquierda, al que se realizó endarterectomía carotídea con bloqueo del plexo cervical superficial por alto riesgo de colapso circulatorio. Dicha estrategia anestésica permitió mantener al paciente despierto durante la cirugía, al valorar continuamente su estado neurológico. Asimismo, se documentaron los cambios transoperatorios en el NIRS (Near-infrared spectroscopy) cerebral y Doppler transcraneal (DTC), los cuales se correlacionaron con el estado clínico del paciente. En un segundo tiempo se hizo cambio valvular aórtico sin complicaciones. En este caso destaca la importancia de la anestesia regional y el monitoreo neurológico con Doppler transcraneal, en pacientes sometidos a endarterectomía carotídea con alto riesgo quirúrgico por EVA crítica.

Abstract: Carotid stenosis occurs in 13% of patients with aortic valve stenosis. The risk of stroke in patients with significant carotid stenosis undergoing heart valve surgery may increase to 11%. Proposing a patient with critical aortic valve stenosis and left ventricular dysfunction to carotid endarterectomy is an anesthetic challenge, where the objective is to avoid hypotension and low cardiac output. Regional anesthesia is an option for these patients. Due to the high incidence of intraoperative stroke during carotid endarterectomy, continuous neurological monitoring is of relevance. We present the case of a 70-year-old man diagnosed with significant carotid stenosis and critical aortic valve stenosis and left ventricular dysfunction who underwent carotid endarterectomy with superficial cervical plexus block due to a high risk of circulatory collapse. In addition, this anesthetic strategy made it possible to keep the patient awake during surgery, and to continuously assess their neurological status. Likewise, transoperative changes in brain NIRS and transcranial Doppler were documented, which correlated with the patient's clinical status. In a second time, aortic valve replacement was performed without complications. This case highlights the importance of regional anesthesia and neurological monitoring in patients undergoing carotid endarterectomy with high surgical risk due to critical aortic valve stenosis.

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This case describes the successful use of transcranial color-coded duplex sonography (TCCD) to diagnose a posterior circulation aneurysm in a patient with subarachnoid hemorrhage. A 33-year-old, was admitted to the ICU after a brain CT scan showed peritroncal subarachnoid hemorrhage. TCCD revealed a rounded image with color Doppler near the P1 portion of the right posterior cerebral artery, which was later confirmed to be a 4 mm aneurysm at the right posterior inferior cerebellar artery (PICA). The aneurysm was treated with coil exclusion and TCCD confirmed its disappearance post-treatment. While TCCD has limitations, including its inability to detect small aneurysms, it is a noninvasive diagnostic tool that provides real-time visualization of the brain and allows for follow-up evaluations. This case demonstrates the potential usefulness of TCCD in diagnosing cerebral aneurysms in patients with subarachnoid hemorrhage and for follow-up evaluations post-treatment.

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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.

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Introducción. El uso del Doppler transcraneal (DTC) en pacientes neurocríticos se reporta cada vez más en las terapias intensivas pediátricas. El objetivo de esta encuesta es conocer los usos y prácticas del DTC en la atención neurocrítica y el proceso de formación del personal que realiza el estudio. Materiales y métodos. Encuesta a profesionales de 23 unidades de terapia intensiva pediátrica de Argentina. Resultados. Porcentaje de respuesta del 86 %. Se utilizó en sospecha de muerte encefálica (n = 20), trauma de cráneo (n = 16) y accidente cerebrovascular (n = 16). El intensivista pediátrico es quien realiza los estudios (n = 13/20). Los encuestados utilizan el Doppler para decidir conductas y tratamientos, comenzar el proceso de evaluación de muerte encefálica, solicitar tomografía de cerebro y manejar la presión de perfusión cerebral con vasopresores. Conclusión. Todos los encuestados utilizan los hallazgos del DTC para guiar tratamientos o conductas. La mitad de los encuestados está poco conforme con la capacitación recibida.

Introduction. The use of transcranial Doppler (TCD) ultrasoundin neurocritical patients is reported to be increasingly common in pediatric intensive care units. The objective of this survey was to know about the use and practice of TCD ultrasound in neurocritical care and the training process of staff members performing it. Materials and methods. Survey administered to providers from 23 pediatric intensive care units of Argentina. Results. The percentage of response was 86%. TCD ultrasound was used for suspected brain death (n = 20), head injury (n = 16), and stroke (n = 16). Pediatric intensivists perform the test (n = 13/20). Surveyed participants use TCD ultrasound to decide on treatment and management, start brain death assessment, request brain computed tomography, and manage cerebral perfusion pressure with vasopressors. Conclusion. All surveyed participants use TCD ultrasound findings to guide management or treatments. Half of surveyed participants are little satisfied with their training.

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This supplementary dataset is supportive of the randomized sham-controlled, double-blind, crossover clinical trial investigating polarity- and intensity-dependent effects of high-definition transcranial electrical stimulation (HD-tDCS) applied over the right temporo-parietal junction on mean middle cerebral artery blood flow velocity (MCA-BFv) bilaterally. Data of eleven healthy right-handed adults (6 women, 5 men; mean age 31 ± 5.6 years old) were analyzed for MCA-BFv, assessed using transcranial doppler ultrasound on the stimulated and the contralateral hemisphere concomitantly, during and after 3 blocks of 2 min HD-tDCS at 1, 2, and 3 mA. Participants received three electrical stimulation conditions (anode center, cathode center, and sham) randomly ordered across different days. The collected data is publicly available at Mendeley Data. This article and the data will inform future related investigations and safety analysis of transcranial non-invasive brain stimulation.

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INTRODUCTION: The use of transcranial Doppler (TCD) ultrasound in neurocritical patients is reported to be increasingly common in pediatric intensive care units. The objective of this survey was to know about the use and practice of TCD ultrasound in neurocritical care and the training process of staff members performing it. MATERIAL AND METHODS: Survey administered to providers from 23 pediatric intensive care units of Argentina. RESULTS: The percentage of response was 86%. TCD ultrasound was used for suspected brain death (n = 20), head injury (n = 16), and stroke (n = 16). Pediatric intensivists perform the test (n = 13/20). Surveyed participants use TCD ultrasound to decide on treatment and management, start brain death assessment, request brain computed tomography, and manage cerebral perfusion pressure with vasopressors. CONCLUSIONS: All surveyed participants use TCD ultrasound findings to guide management or treatments. Half of surveyed participants are little satisfied with their training.

Introducción. El uso del Doppler transcraneal (DTC) en pacientes neurocríticos se reporta cada vez más en las terapias intensivas pediátricas. El objetivo de esta encuesta es conocer los usos y prácticas del DTC en la atención neurocrítica y el proceso de formación del personal que realiza el estudio. Materiales y métodos. Encuesta a profesionales de 23 unidades de terapia intensiva pediátrica de Argentina. Resultados. Porcentaje de respuesta del 86 %. Se utilizó en sospecha de muerte encefálica (n = 20), trauma de cráneo (n = 16) y accidente cerebrovascular (n = 16). El intensivista pediátrico es quien realiza los estudios (n = 13/20). Los encuestados utilizan el Doppler para decidir conductas y tratamientos, comenzar el proceso de evaluación de muerte encefálica, solicitar tomografía de cerebro y manejar la presión de perfusión cerebral con vasopresores. Conclusión. Todos los encuestados utilizan los hallazgos del DTC para guiar tratamientos o conductas. La mitad de los encuestados está poco conforme con la capacitación recibida.

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ABSTRACT Background: Stroke is a serious complication of sickle cell anemia (SCA). The transcranial Doppler (TCD) is the risk-screening tool for ischemic strokes. The objective of the study was to describe the clinical progression of children with SCA who presented with high risk for stroke by TCD or relevant changes by magnetic resonance angiography (MRA) and underwent the regular transfusion program (RTP) and/or hydroxyurea (HU) treatment between 2007 and 2018. Method: This was a neonatal retrospective/prospective cohort study with children born between 1999 and 2014 with the homozygotic form (HbSS) or Sβ0-thalassemia who underwent TCD at least once. Results: Of the 718 children screened during this period, 675 had HbSS and 43 Sβ0-thalassemia. In 54 children (7.5%), all with HbSS, a high-risk TCD (n = 45) or, when the TCD was inconclusive, an MRA with cerebral vasculopathy (n = 9) was used for detection. Of these, 51 started the RTP and the families of three refused treatment. Of the 43 children with a highrisk TCD who initiated the RTP, 29 (67.4%) reverted to low risk. In 18 of them (62%), HU was started at the maximum tolerated dose (MTD) before transfusion discontinuation. None of these 29 patients had a stroke. Eight children (18.6%) maintained a high-risk TCD, even using the RTP/HU and two had a stroke. Conclusions: The TCD was confirmed as a viable tool for tracking patients with a risk for stroke. The RTP was effective in preventing the primary event. New strategies are necessary to prevent stroke using HU and new drugs, in addition to bone marrow transplantation.

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Background: Stroke is one of the highest complications of sickle-cell anemia (SCA). The Transcranial Doppler (TCD) has been adopted worldwide as a gold standard method for detecting alterations in the blood velocity in cerebral arteries. In this study, we investigated the association between laboratory parameters and increased cerebral blood flow velocity in Brazilian SCA pediatric patients. Methods: The study included 159 pediatric patients with SCA, submitted to TCD velocity screening, and the time-averaged maximum mean velocity (TAMMV) was determined in the middle cerebral artery (MCA), anterior cerebral artery (ACA), and distal intracranial internal carotid artery (ICA). We compared cerebral blood flow in patients stratified by the following: TCD1-defined as normal, with TAMMV inferior to 170 cm/s; TCD2-conditional, with TAMMV above 170 cm/s, but less than 199 cm/s; TCD3-altered, with TAMMV greater than or equal to 200 cm/s. Results: TAMMV was negatively correlated with age and weight (p < 0.05). Moreover, TAMMV was associated or correlated with reductions in HbF, RBC, hemoglobin, hematocrit, HDL, and haptoglobin and, increases in MCV, MCH, RDW, reticulocytes, WBC, lymphocytes, monocytes, eosinophils, total and indirect bilirubin, LDH, AST, ALT, glucose, ferritin, and AAT (p < 0.05). Conclusion: The current study highlights the importance of the investigation of hemolytic and inflammatory biomarkers for monitoring the clinical outcome of SCA pediatric patients, to avoid acute or chronic stroke. Moreover, glucose and HDL-C appear useful for predicting higher TAMMV.

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Since neuronal activity is coupled with neurovascular activity, we aimed to analyze the cerebral blood flow hemodynamics during and following high-definition transcranial direct current stimulation (HD-tDCS). We assessed the mean middle cerebral artery blood flow velocity (MCA-BFv) bilaterally using transcranial doppler ultrasound, during and after HD-tDCS, in eleven right-handed healthy adult participants (6 women, 5 men; mean age 31 ± 5.6 years old), with no evidence of brain or cardiovascular dysfunction. The HD-tDCS electrode montage was centered over the right temporo-parietal junction. The stimulation protocol comprised 3 blocks of 2 min at each current intensity (1, 2, and 3 mA) and an inter-stimulus interval of 5 min between blocks. Participants received three electrical stimulation conditions (anode center, cathode center, and sham) on three different days, with an interval of at least 24 h. Stimulation was well tolerated across HD-tDCS conditions tested, and the volunteers reported no significant discomfort related to stimulation. There was no significant difference in the right or the left MCA-BFv during or after the stimulation protocol across all stimulation conditions. We conclude that at a range of intensities, vascular reaction assessed using middle cerebral artery blood flow is not significantly altered during or after HD-tDCS both locally and remotely, which provides further evidence for the safety of HD-tDCS.

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BACKGROUND: Sickle cell anemia (SCA) is the leading cause of childhood stroke. We aimed to evaluate whether altered cerebral flow velocities, as measured by transcranial Doppler (TCD), are associated with vaso-occlusive complications in addition to stroke in pediatric SCA patients. METHODS: We evaluated 37 children aged between 2 and 16 years with SCA who underwent screening for TCD between January 2012 and October 2018. Genotypic profiles and demographic data were collected, TCD examinations were performed during follow-up, and the presence of sickling crises was compared. Survival analyses were performed using simple frailty models, in which each predictor variable was analyzed separately in relation to the occurrence of a sickling crisis. RESULTS: The variables related to sickle cell crises in the univariate analysis were peak systolic velocity (PSV) in the middle cerebral artery (MCA), hazard ratio (HR) 1.01 (1.00-1.02) p = 0.04; end-diastolic velocity (EDV) in the MCA, HR 1.02 (1.01-1.04) p = 0.01; time average mean maximum velocity (TAMMV) in the basilar artery (BA), HR 1.02 (1.00-1.04) p = 0.04; hemoglobin, HR 0.49 (0.38-0.65) p < 0.001; hematocrit, HR 0.78 (0.71-0.85) p < 0.001; leukocyte counts, HR 1.1 (1.05-1.15) p < 0.001; platelets counts, HR 0.997 (0.994-0.999) p = 0.02; and reticulocyte numbers, HR 1.14 (1.06-1.23) p < 0.001. CONCLUSIONS: Our results indicate PSV and EDV in the MCA and TAMMV in the BA as markers of risk for the occurrence of sickling crises in SCA.

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ABSTRACT Introduction: Transcranial Doppler ultrasonography (TCD) is a technique that allows measurement of blood flow from the basal intracerebral vessels. It is relatively inexpensive, non-invasive, can be performed at the bedside, and allows monitoring in acute emergency settings and for prolonged periods with a high temporal resolution, making it ideal for studying the haemodynamics within the intracranial arteries in neuro-Behcet's disease (NBD) and neuro-psychiatric lupus (NPSLE). Our aim was to assess the cerebral haemodynamic patterns in patients with NBD and NPSLE using TCD, while brain lesions were examined using magnetic resonance imaging (MRI). Material and methods: Case-control prospective study of 30 neuro-Behcet's disease patients, 25 neuro-psychiatric lupus patients and 26 healthy age-matched volunteers. All patients and healthy controls were examined by TCD. Only the groups of patients underwent cranial magnetic resonance imaging (MRI). Results: Transcranial Doppler (TCD) values for middle cerebral artery (MCA), anterior cerebral artery (ACA), posterior cerebral artery (PCA), vertebral artery (VA) and basilar artery (BA) in NBD, NPSLE and control groups were measured. The results showed that there was a significant decrease in mean blood flow velocities in all the arteries examined in NBD and NPSLE patients. There was also a significant increase in the pulsatile index of PCA, VA and BA between NBD and NPSLE patients. The same results were obtained when comparing NBD versus controls. However, there was no significant difference between the NPSLE patients and the control group. The MRI lesions described were parenchymal lesions in 14 patients (46.7%), and vascular lesions in 4 patients (13.3%). Vascular lesions co-existed with parenchymal lesions (mixed lesion). Parenchymal lesions were in white matter (40%), thalamus (26.7%), brain stem (26.7%) and cerebellum (20%). While, in NPSLE, 23 patients were normal (92%) and only two patients had a vascular lesion (8%). Conclusion: There was a significant decrease in mean blood flow and a significant increase in the pulsatile index among both NBD and NPSLE patients, according to the TCD values.

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