BACKGROUND:  There is limited data available regarding the prevalence of intracranial arterial stenosis (ICAS) among acute ischemic stroke (AIS) patients in Brazil and Latin America.
OBJECTIVE:  The present study sought to investigate the frequency and predictors of ICAS among patients with AIS or transient ischemic attack (TIA) in a Brazilian center, with transcranial color-coded duplex sonography (TCCS) technique.
METHODS:  Consecutive AIS and TIA patients, admitted to an academic public comprehensive stroke center in Brazil from February to December 2014, evaluated by TCCS were prospectively selected. Vascular narrowings > 50% were considered as ICAS, based on ultrasound criteria previously defined in the literature.
RESULTS:  We assessed 170 consecutive patients with AIS or TIA, of whom 27 (15.9%) were excluded due to an inadequate transtemporal acoustic bone window. We confirmed ICAS in 55 patients (38.5%). The most common location was the proximal segment of the middle cerebral artery (28.2%), followed by the vertebral (15.4%), posterior cerebral (13.6%), terminal internal carotid (9.1%) and basilar (8.2%) arteries. On multivariate models adjusting for potential confounders, systolic blood pressure (OR: 1.03, 95%CI: 1.01-1.04; p = 0.008) was independently associated with ICAS.
CONCLUSIONS:  We found significant ICAS in approximately ⅓ of patients admitted with symptoms of AIS or TIA in a public tertiary academic stroke center in Brazil. The TCCS is an accessible and noninvasive technique that can be used to investigate the presence of moderate and severe ICAS, especially in patients who cannot be exposed to more invasive exams, such as the use of intravenous contrast agents.
BACKGROUND:  Dados acerca da prevalência da estenose arterial intracraniana (EAIC) entre os pacientes com acidente vascular isquêmico (AVCi) agudo no Brasil e América Latina são limitados.
OBJECTIVE:  O presente estudo pretendeu investigar a frequência e os preditores da EAIC nos pacientes AVCi ou ataque isquêmico transitório (AIT) em um centro brasileiro utilizando o Doppler transcraniano colorido (duplex transcraniano). MéTODOS:  Pacientes consecutivos com AVCi ou AIT, admitidos entre fevereiro e dezembro de 2014 em um centro acadêmico brasileiro especializado em doenças cerebrovasculares, foram avaliados prospectivamente com duplex transcraniano. Os estreitamentos vasculares > 50% foram considerados como EAIC, baseado em critérios ultrassonográficos definidos previamente na literatura.
RESULTS:  Foram avaliados 170 pacientes com AVCi ou AIT, dos quais 27 (15,9%) foram excluídos em decorrência da janela óssea transtemporal acústica inadequada. Confirmamos EAIC em 55 pacientes (38,5%). A localização mais comum foi o segmento proximal da artéria cerebral média (28,2%), seguida pelas artérias vertebral (15,4%), cerebral posterior (13,6%), carótida interna terminal (9,1%) e basilar (8,2%). No modelo multivariado, ajustado para os potenciais confundidores, a pressão arterial sistólica aumentada (OR: 1,03; IC 95%: 1,01–1,04; p = 0,008) foi independentemente associada a EAIC. CONCLUSãO:  Foi identificada EAIC significativa em quase ⅓ dos pacientes admitidos com sintomas de AVCi ou AIT em um serviço acadêmico público de atendimento especializado em doenças cerebrovasculares. O Doppler transcraniano colorido é uma ferramenta acessível e não invasiva que pode ser utilizada com segurança para a investigação da presença de EAIC moderada ou grave, especialmente nos pacientes que não podem ser expostos a exames complementares mais invasivos com uso de contraste intravenoso.

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

BACKGROUND: Transcranial sonography (TCS) plays a crucial role in diagnosing Parkinson\'s disease. However, the intricate nature of TCS pathological features, the lack of consistent diagnostic criteria, and the dependence on physicians\' expertise can hinder accurate diagnosis. Current TCS-based diagnostic methods, which rely on machine learning, often involve complex feature engineering and may struggle to capture deep image features. While deep learning offers advantages in image processing, it has not been tailored to address specific TCS and movement disorder considerations. Consequently, there is a scarcity of research on deep learning algorithms for TCS-based PD diagnosis.
METHODS: This study introduces a deep learning residual network model, augmented with attention mechanisms and multi-scale feature extraction, termed AMSNet, to assist in accurate diagnosis. Initially, a multi-scale feature extraction module is implemented to robustly handle the irregular morphological features and significant area information present in TCS images. This module effectively mitigates the effects of artifacts and noise. When combined with a convolutional attention module, it enhances the model\'s ability to learn features of lesion areas. Subsequently, a residual network architecture, integrated with channel attention, is utilized to capture hierarchical and detailed textures within the images, further enhancing the model\'s feature representation capabilities.
RESULTS: The study compiled TCS images and personal data from 1109 participants. Experiments conducted on this dataset demonstrated that AMSNet achieved remarkable classification accuracy (92.79%), precision (95.42%), and specificity (93.1%). It surpassed the performance of previously employed machine learning algorithms in this domain, as well as current general-purpose deep learning models.
CONCLUSIONS: The AMSNet proposed in this study deviates from traditional machine learning approaches that necessitate intricate feature engineering. It is capable of automatically extracting and learning deep pathological features, and has the capacity to comprehend and articulate complex data. This underscores the substantial potential of deep learning methods in the application of TCS images for the diagnosis of movement disorders.

BACKGROUND: This study aimed to clarify the characteristics and survival prediction value of transcranial Doppler microembolic signals (MES) in patients with acute cerebral infarction and active cancer.
RESULTS: Between 2017 and 2022, 1089 cases of acute cerebral infarction were recorded within 7 days of disease onset. Among them, transcranial Doppler was successful in 33 patients who had active cancer, and these data were analyzed in this study. The primary outcomes were stroke recurrence and mortality at 3 months. The study population had the following characteristics [median (interquartile range)]: age, 70 years (63-78); body mass index, 21.6 (20-24), National Institutes of Health Stroke Scale 3 (1-6), and modified Rankin Scale score at discharge 1 (1-4). The most common cancer types were lung (24%), pancreatic (24%), and intestinal (18%). MES was present in 16 of 33 patients (48.5%). The presence and number of MES were significantly associated with the levels of D-dimer (P <0.001) and C-reactive protein (P=0.012). Moreover, the presence of MES was associated with multiple ischemic lesions and the 3-territory sign on magnetic resonance imaging. Of the 33 patients, 9 died at 3 months, and 1 had stroke recurrence. On Cox multivariate analysis, using the MES-negative group as a reference, the presence of MES was significantly associated with all-cause death (adjusted hazard ratio, 12.19 [95% CI, 1.45-216.85]; P=0.020).
CONCLUSIONS: In patients with acute ischemic stroke and active cancer, the presence of MES was associated with D-dimer and C-reactive protein levels and multiple and 3-territory ischemic lesions, and was predictive of short-term survival.

Face masks are crucial parts of personal protective equipment (PPE) to reduce the risk of respiratory infections. The COVID-19 outbreak has increased healthcare workers’ use of face masks. This study aimed to evaluate changes in cerebrovascular response among healthcare workers using surgical and N95 respirator masks. 

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90 healthcare workers: 30 wearing surgical masks, 30 wearing N95 respirators, and 30 without masks were included. After two-hour of face mask use, the baseline mean flow velocity (MFV) and the mean breath-holding index (BHI) of the bilateral middle cerebral arteries (MCAs) were evaluated with transcranial Doppler ultrasound. The presence of de-novo headache was recorded. BHI values ​​below 0.69 were evaluated as a sign of impaired cerebrovascular reactivity (CVR). 

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The rate of de-novo headache was significantly higher in the N95 respirator mask group (p = 0.004). Compared to the control and surgical mask groups, the N95 respirator mask group had significantly lower values of the baseline MFV of the right MCA (p = 0.003 and p = 0.021, respectively) and mean BHI (p = 0.003 and p = 0.012, respectively). Still, only one N95 respirator mask user had a mean BHI value below 0.69.

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Surgical masks did not signi­fi­cantly affect cerebral hemodynamics. Although N95 respirator mask use significantly decreased BHI values, the CVR is still within normal limits, and the development of de-novo headache is not directly associated with low CVR. 

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Az arcmaszkok a légzőszervi fertőzések kockázatának csökkentésére alkalmazott személyes védőfelszerelés (PPE) elengedhetetlen részét képezik. A Covid-19-járvány hatására fokozódott az egészségügyi dolgozók arcmaszkhasználata. Tanulmányunk célja az volt, hogy értékeljük a sebészeti és az N95 respirátor maszkot viselő egészségügyi dolgozók körében bekövetkező cerebrovascularis válasz változásait.

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Összesen 90 egészségügyi dolgozót vontunk be a tanulmányba: 30-an sebészeti maszkot és 30-an N95 respirátor maszkot viseltek, míg 30-an nem viseltek maszkot. Kétórás maszkhasználat után trans­cranialis Doppler-ultrahanggal értékeltük a bilaterális középagyi artériák (MCA) átlagos áramlási sebességét (MFV) és átlagos légzéstartási indexét (BHI). Rögzítettük a de novo fejfájás jelenlétét. A 0,69 alatti BHI-értékeket a károsodott cerebrovascularis reaktivitás (CVR) jelének tekintettük. 

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A de novo fejfájás előfor­dulási aránya szignifikánsan magasabb volt az N95 légzőmaszkot viselő csoportban (p = 0,004). Az N95 légzőmaszkot viselő csoportban a jobb MCA átlagos áramlási sebességének kiindulási értéke (p = 0,003, illetve p = 0,021) és az átlagos BHI-értékek (p = 0,003 és p = 0,012) szignifikánsan alacsonyabbak voltak a kontroll- és a sebészeti maszkot viselő csoportok értékeihez képest. Mindazonáltal, csak egy N95 légzőmaszkot viselő személy esetében volt az átlagos BHI-érték 0,69 alatt.

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A sebészeti maszk hasz­nálata nem befolyásolta szignifikánsan a ce­rebralis hemodinamikát. Habár az N95 lég­zőmaszk használata szignifikánsan csökkentette a BHI-értékeket, a CVR-értékek továbbra is a normáltartományban voltak, és a de novo fejfájás kialakulása nem volt közvetlen összefüggésben az alacsony CVR-rel.

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BACKGROUND:  Arteritis is a complication of neurocysticercosis (NCC), which is not well known and could trigger strokes. The transcranial Doppler ultrasound (TCD) is a noninvasive method for detecting, staging, and monitoring cerebrovascular diseases. Nonetheless, the utility of TCD to evaluate cerebral hemodynamic changes, suggesting vasculitis associated with NCC remains uncertain.
OBJECTIVE:  To evaluate cerebral hemodynamic changes using TCD in patients with subarachnoid and parenchymal NCC.
METHODS:  There were 53 patients with NCC evaluated at a reference hospital for neurological diseases included (29 with subarachnoid and 24 with parenchymal). Participants underwent a clinical interview and serology for cysticercosis and underwent TCD performed within 2 weeks of enrollment. Mean flow velocity, peak systolic velocity, end diastolic velocity, and pulsatility index were recorded.
RESULTS:  Among the participants, there were 23 (43.4%) women, with a median age of 37 years (IQR: 29-48). Cerebral hemodynamic changes suggesting vasculitis were detected in 12 patients (22.64%); the most compromised vessel was the middle cerebral artery in 11 (91.67%) patients. There were more females in the group with sonographic signs of vasculitis (10/12, 83.33% vs. 13/41, 31.71%; p = 0.002), and this was more frequent in the subarachnoid NCC group (9/29, 31.03% vs. 3/24, 12.5%; p = 0.187), although this difference did not reach statistical significance.
CONCLUSIONS:  Cerebral hemodynamic changes suggestive of vasculitis are frequent in patients with NCC and can be evaluated using TCD.
BACKGROUND:  La arteritis es una complicación de la neurocisticercosis (NCC), que no siempre se conoce y podría desencadenar enfermedad cerebrovascular. La ultrasonografía Doppler transcraneal (DTC) es un método no invasivo que sirve para detectar y monitorizar enfermedades cerebrovasculares. No obstante, la utilidad de la DTC para evaluar los cambios hemodinámicos cerebrales que sugieren vasculitis asociada a NCC sigue siendo incierta.
OBJECTIVE:  Evaluar los cambios hemodinámicos cerebrales utilizando DTC en pacientes con NCC subaracnoidea y parenquimal. MéTODOS:  Se incluyeron 53 pacientes con NCC (29 con subaracnoidea y 24 con parenquimal) evaluados en un hospital de referencia para enfermedades neurológicas. Los participantes se sometieron a una entrevista clínica y serología para cisticercosis y a una DTC realizada dentro de las 2 semanas posteriores a la inscripción. Se registraron la velocidad media del flujo, la velocidad sistólica máxima, la velocidad diastólica final y el índice de pulsatilidad.
RESULTS:  Los participantes incluyeron 23 (43,4%) mujeres con una mediana de edad de 37 años (rango intercuartílico [RIC]: 29–48). Se detectaron cambios hemodinámicos cerebrales sugestivos de vasculitis en 12 pacientes (22,64%); el vaso más comprometido fue la arteria cerebral media, en 11 (91,67%) pacientes. Hubo más mujeres en el grupo con signos ecográficos de vasculitis (10/12, 83,33% versus 13/41, 31,71%; p = 0,002), y esto fue más frecuente en el grupo de NCC subaracnoidea (9/29, 31,03% versus 3/24, 12,5%; p = 0,187), aunque esta diferencia no alcanzó significancia estadística. CONCLUSIóN:  Los cambios hemodinámicos cerebrales sugestivos de vasculitis son frecuentes en pacientes con NCC y pueden evaluarse mediante DTC.

BACKGROUND: Cerebrovascular autoregulation in patients with acute and chronic liver failure is often impaired, yet an intact autoregulation is essential for the demand-driven supply of oxygenated blood to the brain. It is unclear, whether there is a connection between cerebrovascular autoregulation during liver transplantation (LTX) and the underlying disease, and if perioperative anesthesiologic consequences can result from this.
METHODS: In this prospective observational pilot study, data of twenty patients (35% female) undergoing LTX were analyzed. Cerebral blood velocity was measured using transcranial doppler sonography and was correlated with arterial blood pressure. The integrity of dynamic cerebrovascular autoregulation (dCA) was evaluated in the frequency domain through transfer function analysis (TFA). Standard clinical parameters were recorded. Mixed one-way ANOVA and generalized estimating equations were fitted to data involving repeated measurements on the same patient. For all other correlation analyses, Spearman\'s rank correlation coefficient (Spearman\'s-Rho) was used.
RESULTS: Indications of impaired dCA are seen in frequency domain during different phases of LTX. No correlation was found between various parameter of dCA and primary disease, delirium, laboratory values, length of ICU or hospital stay, mortality or surgical technique.
CONCLUSIONS: Although in most cases the dCA has been impaired during LTX, the heterogeneity of the underlying diseases seems to be too diverse to draw valid conclusions from this observational pilot study.

OBJECTIVE: In hydrocephalus patients, after ventriculoperitoneal (VP) shunt, decrease in pulsatility index (PI) correlates with decrease in ventricle size. Also, increase in PI is noted in obstructed or malfunctioning VP shunts. However, previous studies were either done in infants and children or included patients of all age groups. Our aim was to compare PI before and after successful VP shunt surgery in adult patients and also the trend of transcranial Doppler (TCD) parameters for 3 days after surgery.
METHODS: A prospective, observational study was done in 20 adult patients undergoing VP shunt. Clinical features, vitals, Evans index, and TCD parameters were noted in the preoperative period. A computed tomography (CT) head was repeated 4-6 h after surgery, and the position of ventricular end of shunt was confirmed and Evans index was calculated. The vitals and TCD parameters were noted at same time and for the next 2 days. Repeated measures analysis of variance (ANOVA) and paired t-test were uses for statistical analysis.
RESULTS: A total of 18 patients were included for statistical analysis. The mean preoperative PI was 1.19 ± 0.24 and the postoperative PI after surgery was 0.97 ± 0.17, 0.97 ± 0.23, and 0.94 ± 0.21 (P = 0.0039) on postoperative day (POD) 1 (POD1), POD2, and POD3, respectively. The mean preoperative value of Evans index was 0.37 ± 0.06 and there was statistically significant (P = < 0.001) reduction to 0.33 ± 0.07 after VP shunt surgery. The change in PI and change in Evans index were found to be positively correlated (r = 0.34 and P = 0.0013).
CONCLUSIONS: The decrease in PI after VP shunt surgery correlates with decrease in ventricular size. Any increase in PI in the postoperative period should raise the suspicion of malfunctioning of VP shunt.

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