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1.
Int J Stroke ; : 17474930241248516, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38591748

RESUMO

RATIONALE: Meta-analyses of case series of non-arteritic central retinal artery occlusion (CRAO) indicate beneficial effects of intravenous thrombolysis when initiated early after symptom onset. Randomized data is lacking to address this question. AIMS: REVISION investigates intravenous alteplase within 4.5 hours of monocular vision loss due to acute CRAO. METHODS: Randomized (1:1), double-blind, placebo-controlled, multicenter adaptive phase III trial. STUDY OUTCOMES: Primary outcome is functional recovery to normal or mildly impaired vision in the affected eye defined as best corrected visual acuity of the Logarithm of the Minimum An-gle of Resolution of 0.5 or less at 30 days (intention-to-treat analysis). Secondary efficacy out-comes include modified Rankin Score at 90 days and quality of life. Safety outcomes include symptomatic intracranial hemorrhage, major bleeding (International Society on Thrombosis and Haemostasis definition) and mortality. Exploratory analyses of optical coherence tomogra-phy/angiography, ultrasound and MRI biomarkers will be conducted. SAMPLE SIZE: Using an adaptive design with interim analysis at 120 patients, up to 422 participants (211 per arm) would be needed for 80% power (one-sided alpha 0.025) to detect a difference of 15%, assuming functional recovery rates of 10% in the placebo arm and 25% in the alteplase arm. DISCUSSION: By enrolling patients within 4.5 hours of CRAO onset, REVISION uses insights from meta-analyses of CRAO case series and randomized thrombolysis trials in acute ischemic stroke. Increased rates of early reperfusion and good neurological outcomes in stroke may trans-late to CRAO with its similar pathophysiology. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04965038; EU Trial Number: 2023-507388-21-00.

2.
Stroke ; 53(1): 177-184, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34496617

RESUMO

BACKGROUND AND PURPOSE: Cardiac ultrasound to identify sources of cardioembolism is part of the diagnostic workup of acute ischemic stroke. Recommendations on whether transesophageal echocardiography (TEE) should be performed in addition to transthoracic echocardiography (TTE) are controversial. We aimed to determine the incremental diagnostic yield of TEE in addition to TTE in patients with acute ischemic stroke with undetermined cause. METHODS: In a prospective, observational, pragmatic multicenter cohort study, patients with acute ischemic stroke or transient ischemic attack with undetermined cause before cardiac ultrasound were studied by TTE and TEE. The primary outcome was the rate of treatment-relevant findings in TTE and TEE as defined by a panel of experts based on current evidence. Further outcomes included the rate of changes in the assessment of stroke cause after TEE. RESULTS: Between July 1, 2017, and June 30, 2019, we enrolled 494 patients, of whom 492 (99.6%) received TTE and 454 (91.9%) received TEE. Mean age was 64.7 years, and 204 (41.3%) were women. TEE showed a higher rate of treatment-relevant findings than TTE (86 [18.9%] versus 64 [14.1%], P<0.001). TEE in addition to TTE resulted in 29 (6.4%) additional patients with treatment-relevant findings. Among 191 patients ≤60 years additional treatment-relevant findings by TEE were observed in 27 (14.1%) patients. Classification of stroke cause changed after TEE in 52 of 453 patients (11.5%), resulting in a significant difference in the distribution of stroke cause before and after TEE (P<0.001). CONCLUSIONS: In patients with undetermined cause of stroke, TEE yielded a higher number of treatment-relevant findings than TTE. TEE appears especially useful in younger patients with stroke, with treatment-relevant findings in one out of seven patients ≤60 years. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03411642.


Assuntos
Ecocardiografia Transesofagiana/normas , Ecocardiografia/normas , Cardiopatias/diagnóstico por imagem , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/terapia , Idoso , Estudos de Coortes , Ecocardiografia/tendências , Ecocardiografia Transesofagiana/tendências , Feminino , Cardiopatias/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Acidente Vascular Cerebral/epidemiologia , Resultado do Tratamento
3.
J Stroke Cerebrovasc Dis ; 30(7): 105828, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34010777

RESUMO

Central retinal artery occlusion (CRAO) is a form of acute ischemic stroke which affects the retina. Intravenous thrombolysis is emerging as a compelling therapeutic approach. However, it is not known which patients may benefit from this therapy because there are no imaging modalities that adequately distinguish viable retina from irreversibly infarcted retina. The inner retina receives arterial supply from the central retinal artery and there is robust collateralization between this circulation and the outer retinal circulation, provided by the posterior ciliary circulation. Fundus photography can show canonical changes associated with CRAO including a cherry-red spot, arteriolar boxcarring and retinal pallor. Fluorescein angiography provides 2-dimensional imaging of the retinal circulation and can distinguish a complete from a partial CRAO as well as central versus peripheral retinal non-perfusion. Transorbital ultrasonography may assay flow through the central retinal artery and is useful in the exclusion of other orbital pathology that can mimic CRAO. Optical coherence tomography provides structural information on the different layers of the retina and exploratory work has described its utility in determining the time since onset of ischemia. Two experimental techniques are discussed. 1) Retinal functional imaging permits generation of capillary perfusion maps and can assay retinal oxygenation and blood flow velocity. 2) Photoacoustic imaging combines the principles of optical excitation and ultrasonic detection and - in animal studies - has been used to determine the retinal oxygen metabolic rate. Future techniques to determine retinal viability in clinical practice will require rapid, easily used, and reproducible methods that can be deployed in the emergency setting.


Assuntos
Angiofluoresceinografia , Imagem de Perfusão , Fotografação , Oclusão da Artéria Retiniana/diagnóstico por imagem , Artéria Retiniana/diagnóstico por imagem , Tomografia de Coerência Óptica , Ultrassonografia , Animais , Velocidade do Fluxo Sanguíneo , Tomada de Decisão Clínica , Circulação Colateral , Humanos , Técnicas Fotoacústicas , Valor Preditivo dos Testes , Prognóstico , Fluxo Sanguíneo Regional , Artéria Retiniana/fisiopatologia , Oclusão da Artéria Retiniana/fisiopatologia , Oclusão da Artéria Retiniana/terapia
4.
Stroke ; 51(7): 2018-2025, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32568646

RESUMO

BACKGROUND AND PURPOSE: Central retinal artery occlusion results in sudden, painless, usually permanent loss of vision in the affected eye. There is no proven, effective treatment to salvage visual acuity and a clear, unmet need for an effective therapy. In this work, we evaluated the efficacy of intravenous tissue-type plasminogen activator (IV alteplase) in a prospective cohort study and an updated systematic review and meta-analysis. METHODS: We enrolled consecutive patients with acute central retinal artery occlusion within 48 hours of symptoms onset and with a visual acuity of <20/200 from January 2009 until May 2019. The primary outcomes were safety and functional visual acuity recovery. We compared rates of visual recovery between those treated with alteplase within 4.5 hours of symptom onset to those who did not receive alteplase (including an analysis restricted to untreated patients presenting within the window for treatment). We incorporated these results into an updated systematic review and patient-level meta-analysis. RESULTS: We enrolled 112 patients, of whom 25 (22.3% of the cohort) were treated with IV alteplase. One patient had an asymptomatic intracerebral hemorrhage after IV alteplase treatment. Forty-four percent of alteplase-treated patients had recovery of visual acuity when treated within 4.5 hours versus 13.1% of those not treated with alteplase (P=0.003) and 11.6% of those presenting within 4 hours who did not receive alteplase (P=0.03). Our updated patient-level meta-analysis of 238 patients included 67 patients treated with alteplase within 4.5 hours since time last known well with a recovery rate of 37.3%. This favorably compares with a 17.7% recovery rate in those without treatment. In linear regression, earlier treatment correlated with a higher rate of visual recovery (P=0.01). CONCLUSIONS: This study showed that the administration of intravenous alteplase within 4.5 hours of symptom onset is associated with a higher likelihood of a favorable visual outcome for acute central retinal artery occlusion. Our results strongly support proceeding to a randomized, placebo-controlled clinical trial.


Assuntos
Fibrinólise/efeitos dos fármacos , Fibrinolíticos/uso terapêutico , Oclusão da Artéria Retiniana/tratamento farmacológico , Ativador de Plasminogênio Tecidual/uso terapêutico , Administração Intravenosa , Idoso , Estudos de Coortes , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Terapia Trombolítica/métodos , Resultado do Tratamento
5.
Stroke ; 48(5): 1392-1396, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28386036

RESUMO

BACKGROUND AND PURPOSE: We aimed to determine the incidence of co-occurring cerebral ischemia, extent of cerebral small vessel disease, and vascular risk profile of patients with acute retinal ischemia. METHODS: RETIS (Frequency of Acute Silent Brain Infarction and Systematic Evaluation of Stroke Risk in Retinal Ischemia) was a single-center, prospective, observational study comprising ophthalmologic examination, brain magnetic resonance imaging, and extensive diagnostic work-up of vascular risk factors and stroke cause. Silent brain infarctions were identified on diffusion-weighted imaging, leukoaraiosis was quantified on fluid-attenuated inversion recovery sequences, and carotid artery stenosis was assessed by carotid ultrasound. RESULTS: Of 112 patients with retinal ischemia, 77 (68.8%) had retinal arterial occlusion, and 35 (31.3%) presented with amaurosis fugax. Silent brain infarctions were found in 17 (15.1%) patients. Internal carotid artery stenosis was present in 19 (17.0%) and severe leukoaraiosis in 29 (25.9%) patients. Atrial fibrillation was detected in 14 (12.5%) patients. Patients with silent brain infarctions had higher rates of internal carotid artery stenosis (35.3% versus 13.7%; P=0.029) than those without, whereas leukoaraiosis and vascular risk factors were comparable between groups. Internal carotid artery stenosis was the only significant predictor of silent brain infarctions in multivariate analysis (odds ratio, 4.27; 95% confidence interval, 1.06-17.23). CONCLUSIONS: Silent cerebral ischemia is present in about 1 in 7 patients with retinal ischemia. The high rate of symptomatic internal carotid artery stenosis suggests that large artery atherosclerosis plays a major role in the pathogenesis of acute retinal ischemia.


Assuntos
Amaurose Fugaz/diagnóstico , Estenose das Carótidas/diagnóstico por imagem , Infarto Cerebral/diagnóstico por imagem , Leucoaraiose/diagnóstico por imagem , Oclusão da Artéria Retiniana/diagnóstico , Idoso , Amaurose Fugaz/epidemiologia , Estenose das Carótidas/complicações , Estenose das Carótidas/epidemiologia , Infarto Cerebral/epidemiologia , Comorbidade , Imagem de Difusão por Ressonância Magnética , Feminino , Humanos , Incidência , Leucoaraiose/epidemiologia , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Oclusão da Artéria Retiniana/epidemiologia , Oclusão da Artéria Retiniana/etiologia , Ultrassonografia
6.
J Ultrasound Med ; 35(9): 2053-6, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27492393

RESUMO

Duplication of the middle cerebral artery is an unusual anatomic variant. Stenosis of one of its branches can be an exceptional cause of stroke and is very difficult to diagnose with transcranial duplex sonography. We report 2 patients with duplication of the middle cerebral artery in whom stenosis of one of its branches led to ischemic stroke and describe the sonographic findings in comparison to other neuroimaging modalities. These cases highlight the utility of adding a coronal insonation plane on top of the traditional axial plane to avoid identification pitfalls in patients with anatomic variants.


Assuntos
Artéria Cerebral Média/anormalidades , Artéria Cerebral Média/fisiopatologia , Acidente Vascular Cerebral/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana/métodos , Constrição Patológica/complicações , Constrição Patológica/diagnóstico por imagem , Constrição Patológica/fisiopatologia , Feminino , Humanos , Pessoa de Meia-Idade , Artéria Cerebral Média/diagnóstico por imagem , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/fisiopatologia
7.
PLoS One ; 11(4): e0152898, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27077372

RESUMO

BACKGROUND: Early recanalization of large cerebral vessels in ischemic stroke is associated with improved clinical outcome, however persisting hypoperfusion leads to poor clinical recovery despite large vessel recanalization. Limited experimental sonothrombolysis studies have shown that addition of microbubbles during treatment can improve microvascular patency. We aimed to determine the effect of two different microbubble formulations on microvascular patency in a rat stroke model. METHODS: We tested BR38 and SonoVue® microbubble-enhanced sonothrombolysis in Wistar rats submitted to 90-minute filament occlusion of the middle cerebral artery. Rats were randomized to treatment (n = 6/group): control, rt-PA, or rt-PA+3-MHz ultrasound insonation with BR38 or SonoVue® at full or 1/3 dose. Treatment duration was 60 minutes, beginning after withdrawal of the filament, and sacrifice was immediately after treatment. Vascular volumes were evaluated with microcomputed tomography. RESULTS: Total vascular volume of the ipsilateral hemisphere was reduced in control and rt-PA groups (p<0.05), but was not significantly different from the contralateral hemisphere in all microbubble-treated groups (p>0.1). CONCLUSIONS: Microbubble-enhanced sonothrombolysis improves microvascular patency. This effect is not dose- or microbubble formulation-dependent suggesting a class effect of microbubbles promoting microvascular reopening. This study demonstrates that microbubble-enhanced sonothrombolysis may be a therapeutic strategy for patients with persistent hypoperfusion of the ischemic territory.


Assuntos
Microbolhas/uso terapêutico , Acidente Vascular Cerebral/terapia , Terapia Trombolítica/métodos , Ondas Ultrassônicas , Animais , Modelos Animais de Doenças , Masculino , Nanotecnologia , Ratos , Ratos Wistar , Acidente Vascular Cerebral/diagnóstico por imagem , Ultrassonografia , Microtomografia por Raio-X
8.
Stroke ; 46(8): 2322-4, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26111890

RESUMO

BACKGROUND AND PURPOSE: Transorbital sonography may help establish diagnosis of central retinal artery occlusion (CRAO). Next to Doppler sonographic proof of CRAO, an intra-arterial spot sign can be detected in some cases. We hypothesized that it reflects calcified components. It may be associated with embolization from atherosclerotic plaques and may negatively influence thrombolysis. METHODS: Prospective monocenter study of 46 patients with ophthalmologically confirmed CRAO. Systemic tissue-type plasminogen activator thrombolysis was performed when appropriate. All patients received etiologic workup. RESULTS: CRAO was confirmed by Doppler in all patients. Fifty-nine percent of patients with arterio-arterial embolization were spot sign-positive compared with 20% from cardiac source (P<0.05) and none with vasculitis. Eleven patients underwent thrombolysis. Clinically relevant visual improvement was only found in absence of a spot sign (P<0.05). CONCLUSIONS: Transbulbar ultrasound is valuable for initial diagnosis and diagnostic workup of CRAO. In the light of inconsistent results of previous thrombolysis trials, ultrasound may identify patients more likely to benefit from thrombolytic treatment.


Assuntos
Oclusão da Artéria Retiniana/diagnóstico por imagem , Oclusão da Artéria Retiniana/tratamento farmacológico , Terapia Trombolítica/tendências , Ultrassonografia Doppler em Cores/tendências , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Resultado do Tratamento
9.
BMC Immunol ; 16: 30, 2015 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-25986484

RESUMO

BACKGROUND: Neuromyelitis optica (NMO) is an autoimmune disorder of the central nervous system, which is characterized by autoantibodies directed against the water channel aquaporin-4 (AQP4). As one of the main water regulators in the central nervous system, APQ4 is supposed to be involved in the dynamics of brain edema. Cerebral edema seriously affects clinical outcome after ischemic stroke; we therefore aimed to investigate whether NMO-antibodies may exert the same functional effects as an AQP4-inhibitor in-vivo in acute ischemic stroke. METHODS: Sixteen male Wistar rats were randomized into two groups twice receiving either purified NMO-IgG or immune globulin from healthy controls, 24 hours and 30 minutes before middle cerebral artery occlusion (MCAO) was performed. T2-weighted MRI was carried out 24 hours after MCAO. RESULTS: MRI-examination showed a significant increase of infarct size in relation to the cerebral hemisphere volume with NMO-IgG treated animals (27.1% ± 11.1% vs. 14.3% ± 7.2%; p < 0.05) when corrected for the space-occupying effect of vasogenic edema formation and similar results without edema correction (34.4% ± 16.4% vs. 17.5% ± 9.3%; p < 0.05). Furthermore, T2-RT revealed a significant increase in cortical brain water content of the treatment group (19.5 ms ± 9.7 ms vs. 9.2 ms ± 5.2 ms; p < 0.05). CONCLUSIONS: These results support the functional impact of NMO-antibodies and also offer an in-vivo-applicable animal model to investigate the properties of AQP4 in ischemic stroke.


Assuntos
Aquaporina 4/imunologia , Autoanticorpos/administração & dosagem , Edema Encefálico/prevenção & controle , Córtex Cerebral/efeitos dos fármacos , Infarto Cerebral/terapia , Animais , Edema Encefálico/etiologia , Edema Encefálico/imunologia , Córtex Cerebral/patologia , Infarto Cerebral/complicações , Infarto Cerebral/imunologia , Modelos Animais de Doenças , Masculino , Neuromielite Óptica/imunologia , Ratos , Ratos Wistar , Acidente Vascular Cerebral
10.
Artigo em Inglês | MEDLINE | ID: mdl-25657829

RESUMO

BACKGROUND: Early recanalization of occluded vessels in stroke is closely associated with improved clinical outcome. Microbubble-enhanced sonothrombolysis is a promising therapy to improve recanalization rates and reduce the time to recanalization. Testing any thrombolytic therapy requires a model of thromboembolic stroke, but to date these models have been highly variable with regards to clot stability. Here, we developed a model of thromboembolic stroke in rats with site-specific delivery of platelet-rich clots (PRC) to the main stem of the middle cerebral artery (MCA). This model was used in a subsequent study to test microbubble-enhanced sonothrombolysis. METHODS: In Study 1 we investigated spontaneous recanalization rates of PRC in vivo over 4 hours and measured infarct volumes at 24 hours. In Study 2 we investigated tPA-mediated thrombolysis and microbubble-enhanced sonothrombolysis in this model. RESULTS: Study 1 demonstrated stable occlusion out to 4 hours in 5 of 7 rats. Two rats spontaneously recanalized at 40 and 70 minutes post-embolism. Infarct volumes were not significantly different in recanalized rats, 43.93 ± 15.44% of the ischemic hemisphere, compared to 48.93 ± 3.9% in non-recanalized animals (p = 0.7). In Study 2, recanalization was not observed in any of the groups post-treatment. CONCLUSIONS: Site specific delivery of platelet rich clots to the MCA origin resulted in high rates of MCA occlusion, low rates of spontaneous clot lysis and large infarction. These platelet rich clots were highly resistant to tPA with or without microbubble-enhanced sonothrombolysis. This resistance of platelet rich clots to enhanced thrombolysis may explain recanalization failures clinically and should be an impetus to better clot-type identification and alternative recanalization methods.

11.
J Stroke Cerebrovasc Dis ; 23(9): e421-2, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24957310

RESUMO

Sudden monocular blindness is frequently caused by central retinal artery occlusion (CRAO) from embolic sources. Treatment options are insufficient, and spontaneous prognosis toward visual recovery is poor. In addition to ophthalmologic evaluation, transorbital sonographic assessment of the central retinal artery may help establish early diagnosis by Doppler sonographic proof of occlusion and, in some cases, by B-mode detection of an intra-arterial "spot sign". We report the case of a patient with recurrent amaurosis fugax and subsequent CRAO. Ultrasound examination after 2 incidences of amaurosis fugax demonstrated a patent but stenotic central retinal artery, with stenosis caused by an embolus visualized as a "spot sign". The following day, persisting amaurosis suddenly developed. Sonographic re-evaluation revealed downstream dislodgment of the "spot sign" and complete arterial occlusion. Thrombolytic treatment did not result in clinical improvement. In conclusion, this case report describes a single case of repeated amaurosis fugax and deterioration to CRAO via embolization into the central retinal artery and consecutive downstream dislodgment. It emphasizes that ultrasound may render valuable diagnostic information in patients with acute central retinal artery embolization toward its embolic etiology and its risk of subsequent deterioration.


Assuntos
Amaurose Fugaz/diagnóstico , Oclusão da Artéria Retiniana/diagnóstico , Idoso , Amaurose Fugaz/diagnóstico por imagem , Amaurose Fugaz/etiologia , Estenose das Carótidas/complicações , Humanos , Masculino , Recidiva , Oclusão da Artéria Retiniana/complicações , Oclusão da Artéria Retiniana/diagnóstico por imagem , Terapia Trombolítica , Falha de Tratamento , Ultrassonografia
12.
J Neuroimaging ; 24(5): 479-83, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24033644

RESUMO

BACKGROUND AND PURPOSE: Previous studies have suggested that transient global amnesia (TGA) may be provoked by cerebral venous congestion due to a reflux during Valsalva maneuver (VM) caused by internal jugular venous valve incompetence (IJVVI). We investigated the hemodynamic consequences of postural changes on IJVVI and on intracranial veins in patients with TGA and control subjects. MATERIALS AND METHODS: IJVVI was assessed by means of extracranial color-coded duplex sonography during VM in 28 patients with TGA and 25 controls. The basal vein Rosenthal was examined by transcranial color-coded sonography registering flow velocities (FV) at rest and during VM. These measurements were performed in the supine and in a sitting position. RESULTS: IJVVI was identified in supine position in 19/28 (68%) of TGA patients and in 7/25 (28%) of controls (P < .05). Body position had no effect on the detection of IJVVI. Intracranial venous FV at rest and during VM did neither differ between patients and controls, nor between persons with and without IJVVI. CONCLUSIONS: Consistent with results of other groups, we found a significantly higher rate of IJVVI in TGA patients compared to controls. However, we found no differences of intracranial venous circulation between groups nor an effect of body position. This sheds doubt on the assumption of a causative effect of IJVVI in TGA.


Assuntos
Amnésia Global Transitória/diagnóstico , Amnésia Global Transitória/etiologia , Veias Jugulares/diagnóstico por imagem , Ultrassonografia/métodos , Insuficiência Venosa/complicações , Insuficiência Venosa/diagnóstico por imagem , Válvulas Venosas/diagnóstico por imagem , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Manobra de Valsalva
13.
J Cardiothorac Surg ; 8: 198, 2013 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-24139539

RESUMO

BACKGROUND: Cerebral air microembolization (CAM) is a frequent side effect of diagnostic or therapeutic interventions. Besides reduction of the amount of bubbles, filter systems in the clinical setting may also lead to a dispersion of large gas bubbles and therefore to an increase of the gas-liquid-endothelium interface. We evaluated the production and application of different strictly defined bubble diameters in a rat model of CAM and assessed functional outcome and infarct volumes in relation to the bubble diameter. METHODS: Gas emboli of defined number and diameter were injected into the carotid artery of rats. Group I (n = 7) received 1800 air bubbles with a diameter of 45 µm, group II (n = 7) 40 bubbles of 160 µm, controls (n = 6) saline without gas bubbles; group I and II yielded the same total injection volume of air with 86 nl. Functional outcome was assessed at baseline, after 4 h and 24 h following cerebral MR imaging and infarct size calculation. RESULTS: Computer-aided evaluation of bubble diameters showed high constancy (group I: 45.83 µm ± 2.79; group II: 159 µm ± 1.26). Animals in group I and II suffered cerebral ischemia and clinical deterioration without significant difference. Infarct sizes did not differ significantly between the two groups (p = 0.931 u-test). CONCLUSIONS: We present further development of a new method, which allows reliable and controlled CAM with different bubble diameters, producing neurological deficits due to unilateral cerebral damage. Our findings could not display a strong dependency of stroke frequency and severity on bubble diameter.


Assuntos
Infarto Cerebral/etiologia , Modelos Animais de Doenças , Embolia Aérea/patologia , Animais , Ponte Cardiopulmonar , Infarto Cerebral/patologia , Imageamento por Ressonância Magnética , Masculino , Tamanho da Partícula , Ratos , Ratos Wistar
14.
J Cardiothorac Vasc Anesth ; 27(5): 876-83, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23791496

RESUMO

OBJECTIVE: Evaluation of a novel approach to eliminate air microemboli from extracorporeal circulation via ultrasonic destruction. DESIGN: In vitro proof-of-concept study. SETTING: Research laboratory. PARTICIPANTS: None. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: An extracorporeal circulation device was filled with human blood circulating at 3 L/min. Air bubbles were injected into the system. For bubble destruction, the blood in the tubing system was repeatedly insonated for 3 minutes using a therapeutic 60-kHz device, with variation of intensity and duty cycle settings, ranging from 0.2 W/cm² to 1.0 W/cm² and from duty cycle 60% to continuous wave (CW). Number and diameter of air microemboli were counted upstream and downstream of the ultrasound device by a 2-channel microemboli Doppler detector. For safety assessment, circulating blood was insonated continuously for 2 hours at 0.8 W/cm² CW and compared with circulation without insonation; and standard blood parameters were analyzed. Without treatment, 1,313 to 1,580 emboli were detected upstream, diameter ranging between 10 and 130 µm. Ultrasound treatment eliminated up to 87% of all detected bubbles in cw application (p<0.01) and showed comparable effects at intensities from 0.4 W/cm² to 1.0 W/cm² cw. Bubbles sized>15 µm almost were eliminated completely (p<0.001). Pulsed wave application rendered inferior results (p>0.05). No relevant changes of blood parameters were observed compared with control circulation. CONCLUSIONS: Ultrasound destruction of air emboli is a very efficient method to reduce number and size of emboli. Within the limits of safety assessment, the authors could not detect relevant side effects on standard blood parameters.


Assuntos
Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Embolia Aérea/prevenção & controle , Circulação Extracorpórea/métodos , Embolia Intracraniana/prevenção & controle , Ultrassonografia de Intervenção/métodos , Circulação Extracorpórea/instrumentação , Humanos , Embolia Intracraniana/sangue , Ultrassonografia de Intervenção/instrumentação
16.
J Neuroimaging ; 23(2): 237-9, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21883624

RESUMO

OBJECTIVE: To investigate the potential of the ultrasound-based evaluation of the optic nerve sheath in a patient with spontaneous intracranial hypotension due to cervical cerebrospinal fluid (CSF) leakage. METHODS: Repeated measurements of the optic nerve sheath diameter (ONSD) using B-mode sonography were performed before treatment initiation, during medical treatment, and during a course of repeated placement of epidural blood patches. RESULTS: On admission, transorbital sonography revealed a decreased ONSD of 4.1 mm on the right and 4.3 mm on the left side. After 8 months of treatment with caffeine and computed tomography-guided epidural blood patches a gradual distension of the ONSD into the normal range was bilaterally observed (right: 5.2 mm; left: 5.3 mm). CONCLUSIONS: The ultrasound-based evaluation of the optic nerve sheath may be helpful in detecting CSF hypovolemia and for determination of treatment effects. This report should be seen as a basis for future investigations on the sonographic assessment of the optic nerve sheath in diagnosis and treatment of intracranial hypotension.


Assuntos
Placa de Sangue Epidural , Ecoencefalografia/métodos , Hipotensão Intracraniana/diagnóstico por imagem , Hipotensão Intracraniana/etiologia , Nervo Óptico/diagnóstico por imagem , Derrame Subdural/complicações , Derrame Subdural/diagnóstico por imagem , Feminino , Humanos , Pessoa de Meia-Idade , Órbita/diagnóstico por imagem , Resultado do Tratamento
17.
J Neuroimaging ; 22(1): 42-5, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21121998

RESUMO

BACKGROUND: The use of an ultrasound-based evaluation of the optic nerve sheath diameter (ONSD) has previously been demonstrated for detecting raised intracranial pressure. In order to be feasible in clinical workup, the test qualities of transorbital ultrasonography need to be determined. The aim of this study was therefore to establish normal values and to assess the intra- and interobserver reliability of this method. METHODS: Using a 9-3 MHz linear array transducer, the ONSD of 40 healthy subjects was independently measured by 2 investigators. RESULTS: Depicting the optic nerve and its sheath was possible in all individuals. The mean ONSD was 5.4 ± .6 mm with a range of 4.3-7.6 mm. The intraobserver reliability analyzed with Cronbach's Alpha was found to be high with values between .92 and .97. Pearson's correlation coefficient between the 2 investigators was .81 on the right side and .84 on the left. There was no correlation between ONSD and age, body mass index, or gender. CONCLUSIONS: Transorbital B-mode sonography is a feasible method to assess the ONSD with a high intra- and interobsever reliability. Normal values on ONSD are presented in this study that will be useful in future studies on pathological conditions.


Assuntos
Ecoencefalografia/métodos , Nervo Óptico/diagnóstico por imagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Valores de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Adulto Jovem
18.
Case Rep Neurol ; 3: 97-102, 2011 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-21589846

RESUMO

Limb-shaking transient ischemic attacks (TIA) may occur in patients with insufficient brain perfusion due to an underlying occlusive disease. We present the case of a 64-year-old patient who suffered from repetitive TIA presenting with shaking movements of the right-sided extremities and accompanying speech arrest. Symptoms are documented in the online supplementary video (www.karger.com/doi/10.1159/000327683). These episodes were frequently triggered in orthostatic situations. The diagnosis of limb-shaking TIA was established. The diagnostic workup revealed pseudo-occlusion of the left internal carotid artery, a poor intracranial collateral status and, as a consequence, an exhausted vasomotor reserve capacity. At ultrasound examination, symptoms were provoked by a change of the patient's position from supine to sitting. During evolvement of symptoms, a dramatic decrease of flow velocities in the left middle cerebral artery was observed. This case thus documents the magnitude and dynamics of perfusion failure in a rare manifestation of cerebral ischemic disease.

19.
J Neurol ; 258(11): 2014-9, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21523461

RESUMO

The aim of this work was to investigate the potential of ultrasound-based optic nerve sheath diameter (ONSD) measurements in detecting raised intracranial pressure in patients with idiopathic intracranial hypertension (IIH) and to describe ONSD response to lumbar puncture. In ten patients with newly diagnosed IIH, transorbital sonography was carried out to assess ONSD, OND (optic nerve diameter), and optic disc elevation before and after lumbar puncture. Twenty-five patients with other neurological disorders served as controls. Subjects with IIH showed a significantly enlarged ONSD on both sides (6.4 ± 0.6 mm vs. 5.4 ± 0.5 mm in controls; p < 0.001). The best cut-off value of ONSD for detecting raised ICP was 5.8 mm with a sensitivity of 90% and a specificity of 84%. After lumbar puncture, ONSD decreased bilaterally (right 5.8 ± 0.7 mm, p < 0.004; left 5.9 ± 0.7 mm, p < 0.043). No post-puncture changes could be observed with regard to OND and optic disc elevation. Sonographic ONSD evaluation may be useful as an additional tool to identify patients with raised intracranial pressure, as in IIH. Furthermore, our data suggest a potential usefulness of this method for monitoring of treatment effects. The degree of ONSD response to lumbar puncture differs in subjects with IIH, which may possibly be related to findings of a defective CSF circulation in the optic nerve sheath in this disorder, a state that is referred to as optic nerve compartment syndrome.


Assuntos
Nervo Óptico/diagnóstico por imagem , Pseudotumor Cerebral/diagnóstico por imagem , Adulto , Área Sob a Curva , Feminino , Humanos , Masculino , Pseudotumor Cerebral/cirurgia , Curva ROC , Punção Espinal , Ultrassonografia , Adulto Jovem
20.
J Neurol Neurosurg Psychiatry ; 82(4): 436-40, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21296899

RESUMO

BACKGROUND: Multiple sclerosis (MS) is a chronic, inflammatory demyelinating disease of the central nervous system, believed to be triggered by an autoimmune reaction to myelin. Recently, a fundamentally different pathomechanism termed 'chronic cerebrospinal venous insufficiency' (CCSVI) was proposed, provoking significant attention in the media and scientific community. METHODS: Twenty MS patients (mean age 42.2 ± 13.3 years; median Extended Disability Status Scale 3.0, range 0-6.5) were compared with 20 healthy controls. Extra- and intracranial venous flow direction was assessed by colour-coded duplex sonography, and extracranial venous cross-sectional area (VCSA) of the internal jugular and vertebral veins (IJV/VV) was measured in B-mode to assess the five previously proposed CCSVI criteria. IJV-VCSA ≤ 0.3 cm(2) indicated 'stenosis,' and IJV-VCSA decrease from supine to upright position 'reverted postural control.' The sonographer, data analyser and statistician were blinded to the patient/control status of the participants. RESULTS: No participant showed retrograde flow of cervical or intracranial veins. IJV-VCSA ≤ 0.3 cm(2) was found in 13 MS patients versus 16 controls (p=0.48). A decrease in IJV-VCSA from supine to upright position was observed in all participants, but this denotes a physiological finding. No MS patient and one control had undetectable IJV flow despite deep inspiration (p=0.49). Only one healthy control and no MS patients fulfilled at least two criteria for CCSVI. CONCLUSIONS: This triple-blinded extra- and transcranial duplex sonographic assessment of cervical and cerebral veins does not provide supportive evidence for the presence of CCSVI in MS patients. The findings cast serious doubt on the concept of CCSVI in MS.


Assuntos
Esclerose Múltipla/patologia , Esclerose Múltipla/fisiopatologia , Adulto , Estudos de Casos e Controles , Veias Cerebrais/diagnóstico por imagem , Veias Cerebrais/patologia , Constrição Patológica/diagnóstico por imagem , Constrição Patológica/patologia , Feminino , Humanos , Veias Jugulares/diagnóstico por imagem , Veias Jugulares/patologia , Masculino , Pessoa de Meia-Idade , Esclerose Múltipla/complicações , Esclerose Múltipla/diagnóstico por imagem , Fluxo Sanguíneo Regional/fisiologia , Ultrassonografia Doppler em Cores/métodos , Insuficiência Venosa/complicações , Insuficiência Venosa/diagnóstico por imagem , Insuficiência Venosa/patologia , Insuficiência Venosa/fisiopatologia
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