Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.782
Filtrar
1.
J Clin Neurosci ; 82(Pt A): 115-121, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33317718

RESUMO

Continuous measurement of cerebral blood flow velocity (CBFV) of the middle cerebral artery (MCA) using transcranial Doppler (TCD) and arterial blood pressure (ABP) monitoring enables assessment of cerebrovascular haemodynamics. Further indices describing cerebrovascular function can be calculated from ABP and CBFV, such as the mean index (Mxa) of cerebrovascular autoregulation, the 'time constant of the cerebral arterial bed' (tau), the 'critical closing pressure' (CrCP) and a 'non-invasive estimator of ICP' (nICP). However, TCD is operator-dependent and changes in angle and depth of MCA insonation result in different readings of CBFV. The effect of differing CBFV readings on the calculated secondary indices remains unknown. The aim of this study was to investigate variation in angle and depth of MCA insonation on these secondary indices. In eight patients continuous ABP and ipsilateral CBFV monitoring was performed using two different TCD probes, resulting in four simultaneous CBFV readings at different angles and depths per patient. From all individual recordings, the K-means clustering algorithm was applied to the four simultaneous longitudinal measurements. The average ratios of the between-clusters, sum-of-squares and total sum-of-squares were significantly higher for CBFV than for the indices Mxa, tau and CrCP (p < 0.001, p = 0.007 and p = 0.016) but not for nICP (p = 0.175). The results indicate that Mxa, tau and CrCP seemed to be not affected by depth and angle of TCD insonation, whereas nICP was.


Assuntos
Algoritmos , Circulação Cerebrovascular/fisiologia , Hemodinâmica/fisiologia , Interpretação de Imagem Assistida por Computador/métodos , Ultrassonografia Doppler Transcraniana/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Velocidade do Fluxo Sanguíneo/fisiologia , Feminino , Homeostase/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/fisiologia
2.
PLoS One ; 15(10): e0239653, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33007053

RESUMO

Rapid endovascular thrombectomy, which can only be delivered in specialist centres, is the most effective treatment for acute ischaemic stroke due to large vessel occlusion (LVO). Pre-hospital selection of these patients is challenging, especially in remote and rural areas due to long transport times and limited access to specialist clinicians and diagnostic facilities. We investigated whether combined transcranial ultrasound and clinical assessment ("TUCA" model) could accurately triage these patients and improve access to thrombectomy. We recruited consecutive patients within 72 hours of suspected stroke, and performed non-contrast transcranial colour-coded ultrasonography within 24 hours of brain computed tomography. We retrospectively collected clinical information, and used hospital discharge diagnosis as the "gold standard". We used binary regression for diagnosis of haemorrhagic stroke, and an ordinal regression model for acute ischaemic stroke with probable LVO, without LVO, transient ischaemic attacks (TIA) and stroke mimics. We calculated sensitivity, specificity, positive and negative predictive values and performed a sensitivity analysis. We recruited 107 patients with suspected stroke from July 2017 to December 2019 at two study sites: 13/107 (12%) with probable LVO, 50/107 (47%) with acute ischaemic stroke without LVO, 18/107 (17%) with haemorrhagic stroke, and 26/107 (24%) with stroke mimics or TIA. The model identified 55% of cases with probable LVO who would have correctly been selected for thrombectomy and 97% of cases who would not have required this treatment (sensitivity 55%, specificity 97%, positive and negative predictive values 75% and 93%, respectively). Diagnostic accuracy of the proposed model was superior to the clinical assessment alone. These data suggest that our model might be a useful tool to identify pre-hospital patients requiring mechanical thrombectomy, however a larger sample is required with the use of CT angiogram as a reference test.


Assuntos
Isquemia Encefálica/diagnóstico , Acidente Vascular Cerebral/diagnóstico , Ultrassonografia Doppler Transcraniana/métodos , Idoso , Idoso de 80 Anos ou mais , Angiografia por Tomografia Computadorizada/métodos , Serviços Médicos de Emergência/métodos , Feminino , Humanos , Ataque Isquêmico Transitório , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , População Rural , Sensibilidade e Especificidade , Triagem/métodos , Ultrassonografia/métodos
3.
Medicine (Baltimore) ; 99(43): e22920, 2020 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33120844

RESUMO

RATIONALE: Reversible splenial lesion syndrome (RESLES) is a recently identified clinico-radiological syndrome, the etiology is miscellaneous. Atrial septal defect (ASD) as an underlying etiology for RESLES has not been reported. We first report a rare case of RESLES associated with ASD. The clinical, radiological, and ultrasonic profiles were presented and the pathophysiological mechanism was analyzed. PATIENT CONCERNS: A 23-year-old man presented with headache, drowsiness, occasional paraphasia, and paroxysmal dry cough. Brain magnetic resonance imaging (MRI) on admission showed an ovoid isolated lesion in the splenium of corpus callosum, which exhibited hyperintensity on diffusion-weighted imaging and hypointensity on apparent diffusion coefficient, and completely disappeared on the follow-up MRI 14 days later. ASD was found by transthoracic echocardiography, Right-to-left shunts were detected on color Doppler of transesophageal echocardiography, and microemboli were captured by transcranial Doppler ultrasound. DIAGNOSES: According to his clinical history and imaging results, we confirmed the diagnosis of RESLES associated with ASD. INTERVENTIONS: The patient was treated by oral aspirin and lopidogrel sulfate to inhibit platelet aggregation. In addition, oral nimodipine to suppress vasoconstriction. OUTCOMES: After 14 days treatment, all the symptoms presenting on admission resolved completely. Subsequently, a repair surgery of ASD under thoracoscopy was successfully performed. LESSONS: To our knowledge, this is the first reported case of ASD may be an underlying etiology for RESLES and need require an etiotropic treatment.


Assuntos
Encefalopatias/etiologia , Corpo Caloso/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Comunicação Interatrial/complicações , Administração Oral , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/uso terapêutico , Aspirina/administração & dosagem , Aspirina/uso terapêutico , Encefalopatias/diagnóstico por imagem , Encefalopatias/patologia , Corpo Caloso/patologia , Combinação de Medicamentos , Quimioterapia Combinada , Ecocardiografia/métodos , Seguimentos , Cefaleia/etiologia , Comunicação Interatrial/diagnóstico por imagem , Comunicação Interatrial/tratamento farmacológico , Comunicação Interatrial/cirurgia , Humanos , Lopinavir/administração & dosagem , Lopinavir/uso terapêutico , Masculino , Nimodipina/administração & dosagem , Nimodipina/uso terapêutico , Inibidores da Agregação de Plaquetas/administração & dosagem , Inibidores da Agregação de Plaquetas/uso terapêutico , Ritonavir/administração & dosagem , Ritonavir/uso terapêutico , Síndrome , Resultado do Tratamento , Ultrassonografia Doppler Transcraniana/métodos , Adulto Jovem
4.
Neuron ; 108(1): 93-110, 2020 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-33058769

RESUMO

Visualizing and perturbing neural activity on a brain-wide scale in model animals and humans is a major goal of neuroscience technology development. Established electrical and optical techniques typically break down at this scale due to inherent physical limitations. In contrast, ultrasound readily permeates the brain, and in some cases the skull, and interacts with tissue with a fundamental resolution on the order of 100 µm and 1 ms. This basic ability has motivated major efforts to harness ultrasound as a modality for large-scale brain imaging and modulation. These efforts have resulted in already-useful neuroscience tools, including high-resolution hemodynamic functional imaging, focused ultrasound neuromodulation, and local drug delivery. Furthermore, recent breakthroughs promise to connect ultrasound to neurons at the genetic level for biomolecular imaging and sonogenetic control. In this article, we review the state of the art and ongoing developments in ultrasonic neurotechnology, building from fundamental principles to current utility, open questions, and future potential.


Assuntos
Encéfalo/diagnóstico por imagem , Sistemas de Liberação de Medicamentos/métodos , Ecoencefalografia/métodos , Imagem Molecular/métodos , Ondas Ultrassônicas , Animais , Barreira Hematoencefálica/efeitos da radiação , Encéfalo/fisiologia , Encéfalo/efeitos da radiação , Neuroimagem Funcional , Hemodinâmica , Humanos , Proteínas , Terapia por Ultrassom , Ultrassonografia , Ultrassonografia Doppler Transcraniana/métodos
5.
PLoS One ; 15(9): e0238946, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956397

RESUMO

BACKGROUND: The origin of low frequency cerebral hemodynamic fluctuations (CHF) in the resting state remains unknown. Breath-by breath O2-CO2 exchange ratio (bER) has been reported to correlate with the cerebrovascular response to brief breath hold challenge at the frequency range of 0.008-0.03Hz in healthy adults. bER is defined as the ratio of the change in the partial pressure of oxygen (ΔPO2) to that of carbon dioxide (ΔPCO2) between end inspiration and end expiration. In this study, we aimed to investigate the contribution of respiratory gas exchange (RGE) metrics (bER, ΔPO2 and ΔPCO2) to low frequency CHF during spontaneous breathing. METHODS: Twenty-two healthy adults were included. We used transcranial Doppler sonography to evaluate CHF by measuring the changes in cerebral blood flow velocity (ΔCBFv) in bilateral middle cerebral arteries. The regional CHF were mapped with blood oxygenation level dependent (ΔBOLD) signal changes using functional magnetic resonance imaging. Temporal features and frequency characteristics of RGE metrics during spontaneous breathing were examined, and the simultaneous measurements of RGE metrics and CHF (ΔCBFv and ΔBOLD) were studied for their correlation. RESULTS: We found that the time courses of ΔPO2 and ΔPCO2 were interdependent but not redundant. The oscillations of RGE metrics were coherent with resting state CHF at the frequency range of 0.008-0.03Hz. Both bER and ΔPO2 were superior to ΔPCO2 in association with CHF while CHF could correlate more strongly with bER than with ΔPO2 in some brain regions. Brain regions with the strongest coupling between bER and ΔBOLD overlapped with many areas of default mode network including precuneus and posterior cingulate. CONCLUSION: Although the physiological mechanisms underlying the strong correlation between bER and CHF are unclear, our findings suggest the contribution of bER to low frequency resting state CHF, providing a novel insight of brain-body interaction via CHF and oscillations of RGE metrics.


Assuntos
Circulação Cerebrovascular/fisiologia , Taxa Respiratória/fisiologia , Adulto , Velocidade do Fluxo Sanguíneo/fisiologia , Encéfalo/fisiologia , Dióxido de Carbono/sangue , Feminino , Voluntários Saudáveis , Hemodinâmica/fisiologia , Humanos , Imagem por Ressonância Magnética/métodos , Masculino , Artéria Cerebral Média/fisiologia , Oxigênio/sangue , Pressão Parcial , Respiração , Descanso/fisiologia , Ultrassonografia Doppler Transcraniana/métodos , Vasodilatação/fisiologia
6.
BMC Neurol ; 20(1): 268, 2020 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-32631262

RESUMO

BACKGROUND: The ultrasound based non-invasive ICP measurement method has been recently validated. Correlation of symptoms and signs of intracranial hypertension with actual ICP measurements in patients with large intracranial tumors is controversial. The purpose of this study was to assess ICP in patients with brain tumors, presenting with neurological signs and symptoms of elevated ICP and to further evaluate the value and utility of non-invasive ICP monitoring. METHODS: Twenty patients underwent non-invasive ICP measurement using a two-depth transcranial Doppler ultrasound designed to simultaneously compare pulse dynamics in the proximal (intracranial), and the distal (extracranial) intraorbital segments of the ophthalmic artery through the closed eyelid. RESULTS: Forty-eight measurements were analyzed. Radiological characteristics included tumor volume (range = 5.45-220.27cm3, mean = 48.81 cm3), perilesional edema (range = 0-238.27cm3, mean = 74.40 cm3), and midline shift (mean = 3.99 mm). All ICP measurements were in the normal range of 7-16 mmHg (ICPmean: 9.19 mmHg). The correlation of demographics, clinical and radiological variables in a bivariate association, showed a statistically significant correlation with neurological deficits and ICPmax (p = 0.02) as well as ICPmean (p = 0.01). The correlation between ICP and neurological deficits, showed a negative value of the estimate. The ICP was not increased in all cases, whether ipsilateral nor contralateral to the tumor. The multivariate model analysis demonstrated that neurological deficits were associated with lower ICPmax values, whereas maximum tumor diameter was associated with larger ICPmax values. CONCLUSIONS: This study demonstrated that ICP in patients with intracranial tumors and mass effect is not necessarily increased. Therefore, clinical signs of intracranial hypertension do not necessarily reflect increased ICP.


Assuntos
Neoplasias Encefálicas/complicações , Hipertensão Intracraniana/diagnóstico , Ultrassonografia Doppler Transcraniana/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Pressão Intracraniana , Masculino , Pessoa de Meia-Idade , Monitorização Fisiológica/métodos , Artéria Oftálmica/fisiopatologia , Projetos Piloto
7.
Eur J Paediatr Neurol ; 27: 60-66, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32376082

RESUMO

INTRODUCTION: Sturge-Weber syndrome (SWS) is a neurocutaneous syndrome with typical clinical features including seizures, chronic hemiplegia, hemianopsia and intellectual impairment. Progressive clinical decline may be attributable, at least in part, to progressive venous ischemia. Transcranial Doppler (TCD) ultrasonography could be useful to monitor the degree of hemodynamic involvement and its progression. PURPOSE: To determine whether there is an association between the degree of asymmetry in TCD and intensity of clinical and radiological involvement and whether there is a correlation between clinical changes and changes in serial TCD. METHODS: In fourteen SWS pediatric patients and two "possible cases" (infants younger than two years old without previously known brain involvement, but with other typical signs of SWS) mean flow velocity in the middle cerebral arteries (MCA) was measured by TCD in both hemispheres. The percent difference between hemispheres (asymmetry) was calculated. Clinical and radiological severity was scored using scales. The correlation between TCD asymmetry and SWS clinical and radiological scores was analyzed at baseline, as well as the correlation between the changes in the different variables (TCD asymmetry, clinical and radiological cores) during evolution and in relation to the changes due to therapy. RESULTS: The percentage of MCA velocity asymmetry was positively correlated with the clinical severity score (p = 0.04), and with seizure frequency (p = 0.014). Throughout evolution, therapeutic and clinical changes were associated with noticeable changes in transcranial doppler asymmetry in some cases. CONCLUSIONS: TCD may provide a noninvasive method to assess the severity of blood flow abnormalities at baseline and a method to monitor children for progressive changes over time.


Assuntos
Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Síndrome de Sturge-Weber/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana/métodos , Encéfalo/fisiopatologia , Criança , Pré-Escolar , Progressão da Doença , Feminino , Seguimentos , Humanos , Lactente , Masculino , Síndrome de Sturge-Weber/fisiopatologia
8.
Am J Physiol Regul Integr Comp Physiol ; 319(1): R33-R42, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32401627

RESUMO

Cerebral blood flow (CBF) is commonly inferred from blood velocity measurements in the middle cerebral artery (MCA), using nonimaging, transcranial Doppler ultrasound (TCD). However, both blood velocity and vessel diameter are critical components required to accurately determine blood flow, and there is mounting evidence that the MCA is vasoactive. Therefore, the aim of this study was to employ imaging TCD (ITCD), utilizing color flow images and pulse wave velocity, as a novel approach to measure both MCA diameter and blood velocity to accurately quantify changes in MCA blood flow. ITCD was performed at rest in 13 healthy participants (7 men/6 women; 28 ± 5 yr) with pharmaceutically induced vasodilation [nitroglycerin (NTG), 0.8 mg] and without (CON). Measurements were taken for 2 min before and for 5 min following NTG or sham delivery (CON). There was more than a fivefold, significant, fall in MCA blood velocity in response to NTG (∆-4.95 ± 4.6 cm/s) compared to negligible fluctuation in CON (∆-0.88 ± 4.7 cm/s) (P < 0.001). MCA diameter increased significantly in response to NTG (∆0.09 ± 0.04 cm) compared with the basal variation in CON (∆0.00 ± 0.04 cm) (P = 0.018). Interestingly, the product of the NTG-induced fall in MCA blood velocity and increase in diameter was a significant increase in MCA blood flow following NTG (∆144 ± 159 ml/min) compared with CON (∆-5 ± 130 ml/min) (P = 0.005). These juxtaposed findings highlight the importance of measuring both MCA blood velocity and diameter when assessing CBF and document ITCD as a novel approach to achieve this goal.


Assuntos
Circulação Cerebrovascular/fisiologia , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/fisiologia , Ultrassonografia Doppler Transcraniana/métodos , Adulto , Circulação Cerebrovascular/efeitos dos fármacos , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/efeitos dos fármacos , Nitroglicerina/farmacologia , Análise de Onda de Pulso , Ultrassonografia Doppler em Cores , Vasodilatação/efeitos dos fármacos , Vasodilatação/fisiologia , Vasodilatadores/farmacologia , Adulto Jovem
9.
Brain Stimul ; 13(3): 804-814, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32289711

RESUMO

BACKGROUND: Neuromodulation by transcranial focused ultrasound (FUS) offers the potential to non-invasively treat specific brain regions, with treatment location verified by magnetic resonance acoustic radiation force imaging (MR-ARFI). OBJECTIVE: To investigate the safety of these methods prior to widespread clinical use, we report histologic findings in two large animal models following FUS neuromodulation and MR-ARFI. METHODS: Two rhesus macaques and thirteen Dorset sheep were studied. FUS neuromodulation was targeted to the primary visual cortex in rhesus macaques and to subcortical locations, verified by MR-ARFI, in eleven sheep. Both rhesus macaques and five sheep received a single FUS session, whereas six sheep received repeated sessions three to six days apart. The remaining two control sheep did not receive ultrasound but otherwise underwent the same anesthetic and MRI procedures as the eleven experimental sheep. Hematoxylin and eosin-stained sections of brain tissue (harvested zero to eleven days following FUS) were evaluated for tissue damage at FUS and control locations as well as tissue within the path of the FUS beam. TUNEL staining was used to evaluate for the presence of apoptosis in sheep receiving high dose FUS. RESULTS: No FUS-related pre-mortem histologic findings were observed in the rhesus macaques or in any of the examined sheep. Extravascular red blood cells (RBCs) were present within the meninges of all sheep, regardless of treatment group. Similarly, small aggregates of perivascular RBCs were rarely noted in non-target regions of neural parenchyma of FUS-treated (8/11) and untreated (2/2) sheep. However, no concurrent histologic abnormalities were observed, consistent with RBC extravasation occurring as post-mortem artifact following brain extraction. Sheep within the high dose FUS group were TUNEL-negative at the targeted site of FUS. CONCLUSIONS: The absence of FUS-related histologic findings suggests that the neuromodulation and MR-ARFI protocols evaluated do not cause tissue damage.


Assuntos
Encéfalo/diagnóstico por imagem , Técnicas de Imagem por Elasticidade/métodos , Imagem por Ressonância Magnética/métodos , Estimulação Elétrica Nervosa Transcutânea/métodos , Ultrassonografia Doppler Transcraniana/métodos , Animais , Encéfalo/fisiologia , Macaca mulatta , Espectroscopia de Ressonância Magnética/métodos , Masculino , Ovinos
10.
Biomed Res Int ; 2020: 8701759, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32185222

RESUMO

Objectives: To access the distinct values of contrast transcranial Doppler (cTCD), contrast transthoracic echocardiography (cTTE), and contrast transesophageal echocardiography (cTEE) in the diagnosis of right-to-left shunt (RLS) due to patent foramen ovale (PFO) and to define the most practical strategy for the diagnosis of PFO. Methods: 102 patients with a high clinical suspicion for PFO had simultaneous cTCD, cTTE, and cTEE performed. The agitated saline mixed with blood was used to detect right-to-left shunt (RLS). Results: In all 102 patients, the shunt was detected at rest by cTCD in 60.78% of cases, by cTTE in 42.16%, and by cTEE in 47.06%. The positive results of all 3 techniques with Valsalva maneuver (VM) were significantly improved. cTCD showed higher pick-up rate than cTTE (98.04% vs. 89.22%; χ 2 = 12.452, p < 0.05) and the cTEE (98.04% vs. 96.08%; nonsignificant difference) in the diagnosis of PFO. Nevertheless, cTEE, compared with cTTE, underestimated shunting in 44% of patients. The diameter of both PFO entrance and exit was significantly greater in patients with a severe shunt compared with a mild shunt (2.8 ± 1.0 mm vs. 2.0 ± 0.7 mm, t = 3.135, p < 0.05) and the cTEE (98.04% vs. 96.08%; nonsignificant difference) in the diagnosis of PFO. Nevertheless, cTEE, compared with cTTE, underestimated shunting in 44% of patients. The diameter of both PFO entrance and exit was significantly greater in patients with a severe shunt compared with a mild shunt (2.8 ± 1.0 mm vs. 2.0 ± 0.7 mm, t = 3.135, p < 0.05) and the cTEE (98.04% vs. 96.08%; nonsignificant difference) in the diagnosis of PFO. Nevertheless, cTEE, compared with cTTE, underestimated shunting in 44% of patients. The diameter of both PFO entrance and exit was significantly greater in patients with a severe shunt compared with a mild shunt (2.8 ± 1.0 mm vs. 2.0 ± 0.7 mm, t = 3.135, p < 0.05) and the cTEE (98.04% vs. 96.08%; nonsignificant difference) in the diagnosis of PFO. Nevertheless, cTEE, compared with cTTE, underestimated shunting in 44% of patients. The diameter of both PFO entrance and exit was significantly greater in patients with a severe shunt compared with a mild shunt (2.8 ± 1.0 mm vs. 2.0 ± 0.7 mm. Conclusions: The best method to diagnose PFO should be the combination of cTCD, cTTE, and cTEE. And cTCD should be applied as the first choice for screening RLS. Then, cTTE should be performed to quantify the severity of the shunt. Last but not least, cTEE should be performed to assess the morphologies of PFO when the closure is planned. The study provides for clinicians the most practical strategy for diagnosing PFO in the future. However, further trials with a large sample size are required to confirm this finding.


Assuntos
Forame Oval Patente/diagnóstico , Adolescente , Adulto , Idoso , Meios de Contraste/administração & dosagem , Ecocardiografia/métodos , Ecocardiografia Transesofagiana/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ultrassonografia Doppler Transcraniana/métodos , Manobra de Valsalva/fisiologia , Adulto Jovem
11.
Sensors (Basel) ; 20(5)2020 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-32120902

RESUMO

One of the great advancements in the applications of piezoelectric materials is the application for therapeutic medical ultrasound for sonothrombolysis. Sonothrombolysis is a promising ultrasound based technique to treat blood clots compared to conventional thrombolytic treatments or mechanical thrombectomy. Recent clinical trials using transcranial Doppler ultrasound, microbubble mediated sonothrombolysis, and catheter directed sonothrombolysis have shown promise. However, these conventional sonothrombolysis techniques still pose clinical safety limitations, preventing their application for standard of care. Recent advances in sonothrombolysis techniques including targeted and drug loaded microbubbles, phase change nanodroplets, high intensity focused ultrasound, histotripsy, and improved intravascular transducers, address some of the limitations of conventional sonothrombolysis treatments. Here, we review the strengths and limitations of these latest pre-clincial advancements for sonothrombolysis and their potential to improve clinical blood clot treatments.


Assuntos
Ultrassonografia Doppler Transcraniana/métodos , Animais , Meios de Contraste/metabolismo , Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Humanos , Microbolhas , Trombose/metabolismo , Trombose/patologia , Transdutores , Ultrassonografia/métodos
13.
Neurology ; 94(15): e1605-e1613, 2020 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-32161031

RESUMO

OBJECTIVE: Unilateral onset of parkinsonism due to nigrostriatal damage of the contralateral hemisphere is frequent in Parkinson disease (PD). There is evidence for a left-hemispheric bias of motor asymmetry in right-handed patients with PD indicating a hemispheric dominance. Isolated REM sleep behavior disorder (IRBD) constitutes the prodromal stage of PD and other synucleinopathies. To test the hypothesis that right-handed patients with IRBD exhibit left-hemispheric predominance of subclinical nigrostriatal dysfunction, we evaluated this aspect using neuroimaging instruments. METHODS: In 167 right-handed patients with IRBD without parkinsonism, we evaluated in each hemisphere the integrity of the striatal dopaminergic terminals by dopamine transporter (DAT)-SPECT and the substantia nigra echogenicity by transcranial sonography. RESULTS: DAT-SPECT showed lower specific binding ratio (SBR) in the left striatum and left caudate nucleus than in the right striatum and right caudate nucleus. The percentage of patients with lower SBR was greater in the left striatum and left caudate nucleus than in the right striatum and right caudate nucleus. In those who developed a synucleinopathy in <5 years from DAT-SPECT, there was a lower SBR in the left putamen and left caudate nucleus than in the right putamen and right caudate nucleus. Substantia nigra echogenic size was greater in the left than in the right side in patients with hyperechogenicity and among individuals who phenoconverted in <5 years from transcranial sonography. CONCLUSION: Right-handed patients with IRBD exhibit left-hemispheric predominance of subclinical nigrostriatal dysfunction. In premotor PD, the neurodegenerative process begins asymmetrically, initially impairing the nigrostriatal system of the dominant hemisphere.


Assuntos
Proteínas da Membrana Plasmática de Transporte de Dopamina/farmacologia , Dopamina/metabolismo , Doença de Parkinson/fisiopatologia , Transtorno do Comportamento do Sono REM/fisiopatologia , Adulto , Idoso , Corpo Estriado/metabolismo , Corpo Estriado/fisiopatologia , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neuroimagem/métodos , Doença de Parkinson/metabolismo , Putamen/diagnóstico por imagem , Transtorno do Comportamento do Sono REM/diagnóstico , Transtorno do Comportamento do Sono REM/metabolismo , Substância Negra/diagnóstico por imagem , Substância Negra/fisiopatologia , Ultrassonografia Doppler Transcraniana/métodos
14.
Crit Care ; 24(1): 100, 2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-32204723

RESUMO

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2020. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2020. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.


Assuntos
Monitorização Fisiológica/instrumentação , Distúrbios Pupilares/diagnóstico , Encéfalo/diagnóstico por imagem , Estado Terminal/terapia , Medicina de Emergência/instrumentação , Medicina de Emergência/métodos , Humanos , Monitorização Fisiológica/métodos , Monitorização Fisiológica/normas , Manejo da Dor/instrumentação , Medição da Dor/instrumentação , Medição da Dor/métodos , Distúrbios Pupilares/fisiopatologia , Ultrassonografia Doppler Transcraniana/métodos
15.
World Neurosurg ; 138: e718-e724, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32198122

RESUMO

BACKGROUND: Vasospasm, delayed ischemic neurologic deficit (DIND), and ischemic brain lesions after acute subarachnoid hemorrhage (SAH) are associated with increased morbidity and mortality. The purpose of this study was to analyze age cutoffs for vasospasm, DIND, and ischemic brain lesions after SAH. METHODS: This study included 292 aneurysmal SAH patients from January 2005 to December 2015. Patients' data were extracted from a prospective database with measurements of transcranial Doppler sonography. Any vasospasm was defined as a maximum mean flow velocity (MMFV) >120 cm/sec. Severe vasospasms were defined as at least 2 measurements of MMFVs >200 cm/sec or an increase of MMFV >50 cm/sec/24 hours over 2 consecutive days or a new neurologic deficit. All MMFVs >120 cm/sec in absence of severe vasospasm criteria were defined as mild vasospasm. Age-related cutoff values were calculated using receiver operating curve analysis. RESULTS: Any vasospasms occurred in 142 patients and thereof mild vasospasm in 86/142 (60.6%) patients and severe vasospasm in 56/142 patients (39.4%). Significantly higher incidences of any vasospasm (P = 0.005), severe vasospasm (P = 0.003), DIND (P = 0.031), and ischemic brain lesions (P = 0.04) were observed in patients aged <50 years. According to receiver operating curve analysis, the optimal age cutoff was 50 years for the presence of overall vasospasms, severe vasospasms, DIND, and ischemic brain lesions and 65 years for mild vasospasms. CONCLUSIONS: Higher incidences of any vasospasms, severe vasospasms, DIND, and ischemic brain lesions were observed in younger SAH patients.


Assuntos
Isquemia Encefálica/diagnóstico por imagem , Doenças do Sistema Nervoso/diagnóstico por imagem , Hemorragia Subaracnóidea/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana/métodos , Vasoespasmo Intracraniano/diagnóstico por imagem , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/complicações , Isquemia Encefálica/terapia , Circulação Cerebrovascular , Cuidados Críticos , Bases de Dados Factuais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doenças do Sistema Nervoso/etiologia , Valor Preditivo dos Testes , Estudos Prospectivos , Hemorragia Subaracnóidea/complicações , Vasoespasmo Intracraniano/complicações , Vasoespasmo Intracraniano/terapia
16.
Transplant Proc ; 52(4): 1042-1048, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32222394

RESUMO

The ischemic and primary vascular injury of the brainstem (BS) can determine, among other serious conditions, the brain death (BD) of the individual. We present 2 cases of individuals with primary ischemic vascular disease of the BS who evolved to BD and were donors of solid organs and tissues. In both cases, the clinical examination was positive for the diagnosis of BD, and transcranial Doppler did not confirm the pattern of cerebral circulatory arrest that accompanies BD. The magnetic resonance angiography performed on 1 patient confirmed the lesion etiology and the presence of vascular obstruction. Both patients were real and effective organ and tissue donors. In these cases, we suggest not to resort to transcranial Doppler as an auxiliary diagnostic test.


Assuntos
Morte Encefálica/diagnóstico , Unidades de Terapia Intensiva , Exame Neurológico/métodos , Doadores de Tecidos , Adulto , Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Parada Cardíaca/diagnóstico , Humanos , Masculino , Pessoa de Meia-Idade , Doadores de Tecidos/provisão & distribução , Ultrassonografia Doppler Transcraniana/métodos
17.
Cochrane Database Syst Rev ; 2: CD010722, 2020 02 19.
Artigo em Inglês | MEDLINE | ID: mdl-32072609

RESUMO

BACKGROUND: An occlusion or stenosis of intracranial large arteries can be detected in the acute phase of ischaemic stroke in about 42% of patients. The approved therapies for acute ischaemic stroke are thrombolysis with intravenous recombinant tissue plasminogen activator (rt-PA), and mechanical thrombectomy; both aim to recanalise an occluded intracranial artery. The reference standard for the diagnosis of intracranial stenosis and occlusion is intra-arterial angiography (IA) and, recently, computed tomography angiography (CTA) and magnetic resonance angiography (MRA), or contrast-enhanced MRA. Transcranial Doppler (TCD) and transcranial colour Doppler (TCCD) are useful, rapid, noninvasive tools for the assessment of intracranial large arteries pathology. Due to the current lack of consensus regarding the use of TCD and TCCD in clinical practice, we systematically reviewed the literature for studies assessing the diagnostic accuracy of these techniques compared with intra-arterial IA, CTA, and MRA for the detection of intracranial stenosis and occlusion in people presenting with symptoms of ischaemic stroke. OBJECTIVES: To assess the diagnostic accuracy of TCD and TCCD for detecting stenosis and occlusion of intracranial large arteries in people with acute ischaemic stroke. SEARCH METHODS: We limited our searches from January 1982 onwards as the transcranial Doppler technique was only introduced into clinical practice in the 1980s. We searched MEDLINE (Ovid) (from 1982 to 2018); Embase (Ovid) (from 1982 to 2018); Database of Abstracts of Reviews of Effects (DARE); and Health Technology Assessment Database (HTA) (from 1982 to 2018). Moreover, we perused the reference lists of all retrieved articles and of previously published relevant review articles, handsearched relevant conference proceedings, searched relevant websites, and contacted experts in the field. SELECTION CRITERIA: We included all studies comparing TCD or TCCD (index tests) with IA, CTA, MRA, or contrast-enhanced MRA (reference standards) in people with acute ischaemic stroke, where all participants underwent both the index test and the reference standard within 24 hours of symptom onset. We included prospective cohort studies and randomised studies of test comparisons. We also considered retrospective studies eligible for inclusion where the original population sample was recruited prospectively but the results were analysed retrospectively. DATA COLLECTION AND ANALYSIS: At least two review authors independently screened the titles and abstracts identified by the search strategies, applied the inclusion criteria, extracted data, assessed methodological quality (using QUADAS-2), and investigated heterogeneity. We contacted study authors for missing data. MAIN RESULTS: A comprehensive search of major relevant electronic databases (MEDLINE and Embase) from 1982 to 13 March 2018 yielded 13,534 articles, of which nine were deemed eligible for inclusion. The studies included a total of 493 participants. The mean age of included participants was 64.2 years (range 55.8 to 69.9 years). The proportion of men and women was similar across studies. Six studies recruited participants in Europe, one in south America, one in China, and one in Egypt. Risk of bias was high for participant selection but low for flow, timing, index and reference standard. The summary sensitivity and specificity estimates for TCD and TCCD were 95% (95% CI = 0.83 to 0.99) and 95% (95% CI = 0.90 to 0.98), respectively. Considering a prevalence of stenosis or occlusion of 42% (as reported in the literature), for every 1000 people who receive a TCD or TCCD test, stenosis or occlusion will be missed in 21 people (95% CI = 4 to 71) and 29 (95% CI = 12 to 58) will be wrongly diagnosed as harbouring an intracranial occlusion. However, there was substantial heterogeneity between studies, which was no longer evident when only occlusion of the MCA was considered, or when the analysis was limited to participants investigated within six hours. The performance of either TCD or TCCD in ruling in and ruling out a MCA occlusion was good. Limitations of this review were the small number of identified studies and the lack of data on the use of ultrasound contrast medium. AUTHORS' CONCLUSIONS: This review provides evidence that TCD or TCCD, administered by professionals with adequate experience and skills, can provide useful diagnostic information for detecting stenosis or occlusion of intracranial vessels in people with acute ischaemic stroke, or guide the request for more invasive vascular neuroimaging, especially where CT or MR-based vascular imaging are not immediately available. More studies are needed to confirm or refute the results of this review in a larger sample of stroke patients, to verify the role of contrast medium and to evaluate the clinical advantage of the use of ultrasound.


Assuntos
Isquemia Encefálica/diagnóstico por imagem , Constrição Patológica/diagnóstico por imagem , Acidente Vascular Cerebral/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana/métodos , Artérias Cerebrais/diagnóstico por imagem , Humanos , Infarto da Artéria Cerebral Média , Ensaios Clínicos Controlados Aleatórios como Assunto
18.
Clinics (Sao Paulo) ; 75: e1212, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31967281

RESUMO

OBJECTIVE: To evaluate the findings of magnetic resonance angiography (MRA) and transcranial Doppler ultrasound (TCD) in patients with a clinical diagnosis of vertebrobasilar insufficiency (VBI). METHOD: From our outpatient neurotology clinic, we selected patients (using the criteria proposed by Grad and Baloh) with a clinical diagnosis of VBI. We excluded patients with any definite cause for vestibular symptoms, a noncontrolled metabolic disease or any contraindication to MRA or TCD. The patients in the study group were sex- and age-matched with subjects who did not have vestibular symptoms (control group). Our final group of patients included 24 patients (study, n=12; control, n=12). RESULTS: The MRA results did not demonstrate significant differences in the findings between our study and control groups. TCD demonstrated that the systolic pulse velocity of the right middle cerebral artery, end diastolic velocity of the basilar artery, pulsatility index (PI) of the left middle cerebral artery, PI of the right middle cerebral artery, and PI of the basilar artery were significantly higher in the study group than in the control group, suggesting abnormalities affecting the microcirculation of patients with a clinical diagnosis of VBI compared with controls. CONCLUSION: MRA failed to reveal abnormalities in patients with a clinical diagnosis of VBI compared with controls. The PI of the basilar artery, measured using TCD, demonstrated high sensitivity (91%) and specificity (91%) for detecting clinically diagnosed VBI.


Assuntos
Artéria Basilar/diagnóstico por imagem , Angiografia por Ressonância Magnética , Ultrassonografia Doppler Transcraniana/métodos , Insuficiência Vertebrobasilar/diagnóstico por imagem , Velocidade do Fluxo Sanguíneo , Humanos , Microcirculação
19.
Epilepsy Behav ; 102: 106589, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31726317

RESUMO

Brainstem raphe (BR) hypoechogenicity in transcranial sonography (TCS) has been depicted in patients with depression. But, up to date, the association of BR alterations in TCS with depression in patients with epilepsy has never been reported. This study was to investigate the possible role of BR examination via TCS in patients with idiopathic generalized epilepsy with tonic-clonic seizures (IGE-TCS) and depression. Forty-six patients with IGE-TCS and 45 healthy controls were recruited. Echogenicity of the caudate nuclei (CN), lentiform nuclei (LN), substantia nigra (SN), and BR and widths of the lateral ventricle (LV) frontal horns and the third ventricle (TV) were assessed via TCS. The determination of depression was based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV), and depression severity measured by Chinese version Neurological Disorders Depression Inventory for Epilepsy (C-NDDI-E) and Beck Depression Inventory-II (BDI-II). The width of TV in patients with epilepsy was found significantly larger than that in healthy controls (p = 0.001), but there was no significant difference in TV width between patients with IGE-TCS with and without depression. There were no significant differences between patients with IGE-TCS and healthy controls in LV frontal horn width, as well as in SN, CN, LN, and BR echogenicity. Here, it seems that patients with IGE-TCS were detected with smaller SN echogenic area compared with controls though they had no statistical significance. Patients with IGE-TCS with hypoechogenic BR had significantly higher C-NDDI-E and BDI-II scores than those with normal BR signal, and most patients with IGE-TCS with depression exhibited hypoechogenic BR, but few patients with IGE-TCS without depression exhibited hypoechogenic BR. In conclusion, BR echogenic signal alterations in TCS can be a biomarker for depression in epilepsy, but it might not be associated with epilepsy itself. The alterations of SN echogenic area and TV width in TCS may reflect a potential role of SN and diencephalon structure in the pathogenesis of epilepsy, which needs to be further elucidated.


Assuntos
Tronco Encefálico/diagnóstico por imagem , Depressão/diagnóstico por imagem , Epilepsia Generalizada/diagnóstico por imagem , Convulsões/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana/métodos , Adulto , Depressão/epidemiologia , Depressão/psicologia , Epilepsia Generalizada/epidemiologia , Epilepsia Generalizada/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Convulsões/epidemiologia , Convulsões/psicologia , Adulto Jovem
20.
Neurol Clin ; 38(1): 215-229, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31761060

RESUMO

Transcranial Doppler ultrasonography (TCD) is a noninvasive, bedside, portable tool for assessment of cerebral hemodynamics. Modern TCD head frames allow continuous hands-free emboli detection for risk stratification and assessment of treatment efficacy in several cardiovascular diseases. Identifying a focal stenosis, arterial occlusion, and monitoring the treatment effect of intravenous tissue plasminogen activator can easily be accomplished by assessing TCD waveforms and determining prestenotic and poststenotic mean flow velocities. TCD is an excellent screening tool for vasospasm in aneurysmal subarachnoid hemorrhage. The use of intraoperative TCD during carotid endarterectomy and stenting allows optimal intraoperative hemodynamic management. Other applications are also discussed.


Assuntos
Embolia Intracraniana/diagnóstico por imagem , Hemorragia Subaracnóidea/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana/métodos , Vasoespasmo Intracraniano/diagnóstico por imagem , Humanos , Embolia Intracraniana/tratamento farmacológico , Embolia Intracraniana/fisiopatologia , Hemorragia Subaracnóidea/tratamento farmacológico , Hemorragia Subaracnóidea/fisiopatologia , Ativador de Plasminogênio Tecidual/administração & dosagem , Vasoespasmo Intracraniano/tratamento farmacológico , Vasoespasmo Intracraniano/fisiopatologia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...