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1.
J Neurol Sci ; 459: 122981, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38569375

RESUMO

BACKGROUND: Carotid endarterectomy (CEA) has been associated with both cognitive decline and improvement, but the underlying neurovascular mechanisms are unclear. The aim of this study was to investigate the relationship between neurovascular indices and cognitive changes after CEA. METHODS: We studied 55 patients with severe (≥70%) symptomatic or asymptomatic carotid stenosis before and six months after CEA. A wide array of neuropsychological tests was arranged in eight cognitive domains and cognitive functions specific to hemisphere ipsilateral to operation. Differences in cognitive performance between patients and 38 matching healthy controls were studied with linear mixed models. Neurovascular functioning and microembolic signals were assessed with transcranial Doppler ultrasound of the middle cerebral artery. Associations between neurovascular indices and cognitive change were assessed with linear regression analyses. RESULTS: On group level, the CEA patients improved more than controls in working memory, whereas no cognitive deterioration was detected. Also on individual level, improvement was most frequently observed in working memory. Worse preoperative cerebrovascular reactivity was related with improvement in cognitive functions of the ipsilateral hemisphere. Low preoperative pulsatility index was associated with improvement in executive functioning and ipsilateral cognitive functions. Poorer preoperative blood flow velocity associated with improvement in complex attention. Microembolic signals were rare. CONCLUSION: The present findings suggest that CEA may have beneficial long-term effects on cognition. These effects may specifically involve patients with impaired preoperative circulatory adaptive mechanisms.


Assuntos
Estenose das Carótidas , Endarterectomia das Carótidas , Humanos , Endarterectomia das Carótidas/efeitos adversos , Estenose das Carótidas/complicações , Estenose das Carótidas/diagnóstico por imagem , Estenose das Carótidas/cirurgia , Cognição/fisiologia , Artéria Cerebral Média , Função Executiva , Circulação Cerebrovascular/fisiologia
2.
Acta Neurochir (Wien) ; 166(1): 181, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38630203

RESUMO

PURPOSE: It is difficult to precisely predict indirect bypass development in the context of combined bypass procedures in moyamoya disease (MMD). We aimed to investigate the predictive value of magnetic resonance angiography (MRA) signal intensity in the peripheral portion of the major cerebral arteries for indirect bypass development in adult patients with MMD. METHODS: We studied 93 hemispheres from 62 adult patients who underwent combined direct and indirect revascularization between 2005 and 2019 and genetic analysis for RNF213 p.R4810K. The signal intensity of the peripheral portion of the major intracranial arteries during preoperative MRA was graded as a hemispheric MRA score (0-3 in the middle cerebral artery and 0-2 in the anterior cerebral and posterior cerebral arteries, with a high score representing low visibility) according to each vessel's visibility. Postoperative bypass development was qualitatively evaluated using MRA, and we evaluated the correlation between preoperative factors, including the hemispheric MRA score and bypass development, using univariate and multivariate analyses. RESULTS: A good indirect bypass was observed in 70% of the hemispheres. Hemispheric MRA scores were significantly higher in hemispheres with good indirect bypass development than in those with poor indirect bypass development (median: 3 vs. 1; p < 0.0001). Multiple logistic regression analysis revealed hemispheric MRA score as an independent predictor of good indirect bypass development (odds ratio, 2.1; 95% confidence interval, 1.3-3.6; p < 0.01). The low hemispheric MRA score (< 2) and wild-type RNF213 predicted poor indirect bypass development with a specificity of 0.92. CONCLUSION: Hemispheric MRA score was a predictive factor for indirect bypass development in adult patients who underwent a combined bypass procedure for MMD. Predicting poor indirect bypass development may lead to future tailored bypass surgeries for MMD.


Assuntos
Doença de Moyamoya , Adulto , Humanos , Doença de Moyamoya/diagnóstico por imagem , Doença de Moyamoya/cirurgia , Angiografia por Ressonância Magnética , Procedimentos Cirúrgicos Vasculares , Artéria Cerebral Média , Fatores de Transcrição , Adenosina Trifosfatases/genética , Ubiquitina-Proteína Ligases/genética
3.
Physiol Rep ; 12(9): e16027, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38684421

RESUMO

Resistance breathing may restore cardiac output (CO) and cerebral blood flow (CBF) during hypovolemia. We assessed CBF and cerebral autoregulation (CA) during tilt, resistance breathing, and paced breathing in 10 healthy subjects. Blood velocities in the internal carotid artery (ICA), middle cerebral arteries (MCA, four subjects), and aorta were measured by Doppler ultrasound in 30° and 60° semi-recumbent positions. ICA blood flow and CO were calculated. Arterial blood pressure (ABP, Finometer), and end-tidal CO2 (ETCO2) were recorded. ICA blood flow response was assessed by mixed-models regression analysis. The synchronization index (SI) for the variable pairs ABP-ICA blood velocity, ABP-MCA velocities in 0.005-0.08 Hz frequency interval was calculated as a measure of CA. Passive tilting from 30° to 60° resulted in 12% decrease in CO (p = 0.001); ICA blood flow tended to fall (p = 0.04); Resistance breathing restored CO and ICA blood flow despite a 10% ETCO2 drop. ETCO2 and CO contributed to ICA blood flow variance (adjusted R2: 0.9, p < 0.0001). The median SI was low (<0.2) indicating intact CA, confirmed by surrogate date testing. The peak SI was transiently elevated during resistance breathing in the 60° position. Resistance breathing may transiently reduce CA efficiency. Paced breathing did not restore CO or ICA blood flow.


Assuntos
Circulação Cerebrovascular , Homeostase , Humanos , Masculino , Circulação Cerebrovascular/fisiologia , Homeostase/fisiologia , Projetos Piloto , Adulto , Feminino , Velocidade do Fluxo Sanguíneo/fisiologia , Artéria Cerebral Média/fisiologia , Artéria Cerebral Média/diagnóstico por imagem , Débito Cardíaco/fisiologia , Voluntários Saudáveis , Artéria Carótida Interna/fisiologia , Artéria Carótida Interna/diagnóstico por imagem , Pressão Sanguínea/fisiologia
4.
Clin Neurol Neurosurg ; 240: 108240, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38554529

RESUMO

BACKGROUND: IIH is a severe form of headache that often has superimposed migraine and often it is very difficult to distinguish the two forms of headache. Intracranial hemodynamics is a relatively unexplored means of distinguishing between the two forms of headache. OBJECTIVES: We aimed to study intracranial flow dynamics using Transcranial Doppler in patients with IIH, migraine, and normal controls. MATERIALS AND METHODS: It was a hospital-based observational study that included 51 people with IIH, 87 people with migraine, and 101 healthy controls and all were subjected to TCD study after detailed clinical examination. RESULTS: Mean age of patients in three groups were similar with the mean age in IIH being 33.41 ± 10.75 (age in years ± SD). Vision loss was present in 66.67% of patients with IIH, and most common field defect was generalized constriction (27.5%). Neuroimaging was abnormal in 94.11% of patients of IIH with mean CSF pressure was 31.27±5.32 cm of water. Of all the TCD-measured velocities, mean flow velocity (MFV) showed a significant difference in all three groups with (p-value <0.001). The pulsatility index, both for middle cerebral arteries as well as ophthalmic arteries showed a significant difference in the three groups with the highest values in IIH patients (p-value<.001). The mean VMR in IIH (1.11±0.32) was lower than the mean VMR in migraine (1.34±0.43) as well as controls (1.49±0.46). CONCLUSION: TCD parameters like MFV and PI are useful parameters that show considerable variation and can be used to differentiate between IIH and migraine.


Assuntos
Transtornos de Enxaqueca , Ultrassonografia Doppler Transcraniana , Humanos , Ultrassonografia Doppler Transcraniana/métodos , Transtornos de Enxaqueca/diagnóstico por imagem , Transtornos de Enxaqueca/fisiopatologia , Masculino , Adulto , Feminino , Pessoa de Meia-Idade , Circulação Cerebrovascular/fisiologia , Adulto Jovem , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/fisiopatologia , Velocidade do Fluxo Sanguíneo/fisiologia
6.
Eur J Pediatr ; 183(6): 2587-2595, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38488878

RESUMO

It is important to monitor cerebral perfusion in infants because hypo- and hyperperfusion can contribute to neurological injury. This study aimed to clarify the relationship between trans-systolic time (TST) and critical closing pressure (CrCP) or estimated cerebral perfusion pressure (CPPe) in neonates. Moreover, we aimed to determine the TST values in preterm and term infants with stable cerebral perfusion to clarify normative reference data. This multicentre prospective study included infants with arterial lines admitted to the neonatal intensive care units between December 2021 and August 2023. TST, CrCP, and CPPe were calculated using middle cerebral artery waveforms recorded using transcranial Doppler ultrasonography when clinicians collected arterial blood samples. Three hundred and sixty samples were obtained from 112 infants with a gestational age of 32 (interquartile range, 27-37) weeks and a birth weight of 1481 (956-2355) g. TST was positively correlated with CPPe (r = 0.60, p < 0.001), but not with CrCP (r = 0.08, p = 0.10). The normative reference values of TST in preterm and term infants without samples of hyper- or hypocapnia and/or hyper- or hypotension, which may affect cerebral perfusion, were as follows: ≤ 29 weeks, 0.12 (0.11-0.14) s; 30-36 weeks, 0.14 (0.12-0.15) s; and ≥ 37 weeks, 0.16 (0.14-0.17) s, respectively.  Conclusion: TST in neonates significantly correlated with CPPe, but not with CrCP. TST may be a good predictor of cerebral perfusion and potentially have wider clinical applications. What is Known: • Trans-systolic time (TST) is used in evaluating the effects of increased intracranial pressure on cerebral haemodynamics. However, little is known about the efficacy of TST in predicting neonatal cerebral perfusion pressure. What is New: • This study added evidence that TST correlated with estimated cerebral perfusion pressure, but not with critical closing pressure. Additionally, we showed the normative reference values of the TST in preterm and term infants.


Assuntos
Circulação Cerebrovascular , Recém-Nascido Prematuro , Ultrassonografia Doppler Transcraniana , Humanos , Recém-Nascido , Estudos Prospectivos , Circulação Cerebrovascular/fisiologia , Feminino , Masculino , Ultrassonografia Doppler Transcraniana/métodos , Valores de Referência , Unidades de Terapia Intensiva Neonatal , Idade Gestacional , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/fisiopatologia
7.
Methods Mol Biol ; 2761: 623-633, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38427265

RESUMO

Stroke is the third-leading cause of death and the leading cause of acquired adult disability worldwide. Several ischemic stroke models are currently available. However, mimicking focal cerebral ischemia (FCI) is the most common. The formation of an embolic or thrombotic occlusion at or near the middle cerebral artery causes most events in FCI. The current protocol closely mimics the etiology of human stroke and ensures that the results obtained are highly relevant. The method described in this protocol yields reproducible results. The success of this model in ischemic research can be examined through the utilization of Doppler blood flow imaging equipment.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Acidente Vascular Cerebral , Ratos , Humanos , Animais , Infarto da Artéria Cerebral Média/complicações , Modelos Animais de Doenças , Isquemia Encefálica/etiologia , Artéria Cerebral Média/diagnóstico por imagem
8.
Turk Neurosurg ; 34(2): 268-273, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38497180

RESUMO

AIM: To gain a better understanding of ischemia risk related to in-stent stenosis (ISS) or in-stent thrombosis (IST) of the middle cerebral artery (MCA) and lenticulostriate arteries after flow-diverting devices (FDD) deployment from the internal carotid artery (ICA) to proximal middle cerebral artery (M1). MATERIAL AND METHODS: Using data from a prospectively maintained database, we retrospectively evaluated patients who were treated with FDD between January 2015 and 2020 at a single academic center. Only patients with unruptured ICA aneurysms where the FDD was extended into M1 were included. RESULTS: In total, 89 patients with 94 ICA aneurysms were treated with FDD. A total of 34 patients with 36 aneurysms had FDD extending into M1. Of the 34 patients, four experienced MCA, and lenticulostriate territory ischemia. Three patients had in-stent thrombosis (IST), and one patient had severe in-stent stenosis (ISS). The overall ischemic complication rate was 17.6%, which resulted in a permanent neurological deficit in 11.7% of the patients. CONCLUSION: If the distance of the distal neck of the aneurysm to the ICA terminus (ICAT) is ≤5 mm, or if the aneurysm is located directly at the ICAT, FDD should be considered only as a last option when other treatment modalities are not suitable. In addition, in the treatment of distal ICA aneurysms, extra effort should be exerted during the procedure to deploy the FDD without extending into M1. However, when traditional microsurgical clipping and other endovascular procedures are not suitable, the use of FDD is effective in terms of high aneurysm occlusion rates and preventing aneurysm rupture.


Assuntos
Doenças das Artérias Carótidas , Aneurisma Intracraniano , Trombose , Humanos , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/cirurgia , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/cirurgia , Artéria Carótida Interna/diagnóstico por imagem , Artéria Carótida Interna/cirurgia , Estudos Retrospectivos , Constrição Patológica , Resultado do Tratamento , Isquemia
9.
Sci Rep ; 14(1): 6060, 2024 03 13.
Artigo em Inglês | MEDLINE | ID: mdl-38480803

RESUMO

The cerebral arteries, specifically the anterior cerebral artery (ACA) and posterior cerebral artery (PCA), work together with the smaller calibre arteries to provide effective communication between the anterior and posterior circuits of the brain via the circle of Willis (CoW). Morphologic variations of the cerebral arteries and the CoW may alter blood flow to the brain, resulting in intracranial vascular disorders associated with stroke, and aneurysms. This study aimed to document the morphology of the cerebral arteries and the CoW in the South African population. Two hundred and thirty-nine computed tomography angiography scans were assessed. Cerebral arteries and CoW normal morphology and variations were classified as complete, absent, or hypoplastic. The ACA A1 was absent in 4.91%, hypoplastic in 30.40%, fenestrated in 1.06%, and typical in 63.6%. The ACA A2 was absent in 0.42%, hypoplastic in 26.28%, and typical in 69.44%. We found triple ACA A2 in 2.98%, azygos in 1.28% and fenestrated in 1.28%. The middle cerebral artery (MCA) was hypoplastic in 7.35% and typical in 92.64%. The PCA was hypoplastic in 28.74% and typical in 71.25%. Knowledge of the configuration of the CoW plays a significant role in guiding therapeutic decision-making in treating various neurovascular pathologies.


Assuntos
Encéfalo , Artérias Cerebrais , Humanos , África do Sul , Artérias Cerebrais/diagnóstico por imagem , Artérias Cerebrais/anatomia & histologia , Encéfalo/irrigação sanguínea , Círculo Arterial do Cérebro/diagnóstico por imagem , Artéria Cerebral Média , Angiografia Cerebral
10.
Acta Neurochir (Wien) ; 166(1): 148, 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38523166

RESUMO

BACKGROUND: Treating complex middle cerebral artery (MCA) trifurcation aneurysms requires a delicate balance between achieving aneurysm obliteration and preserving vascular integrity. Various cerebral revascularization techniques, including bypass, and clip reconstruction are considered individually or in combination. METHODS: This case report outlines a successful repair of a ruptured neck and base of MCA trifurcation aneurysm using a suturing-clip reconstruction technique. Temporary aneurysm trapping was implemented, with maintained elevated blood pressure to ensure collateral perfusion during repair of ruptured base and neck of MCA aneurysm. CONCLUSION: The suturing-clip reconstruction exhibited long-term radiological stability, emerging as a valuable alternative for managing challenging MCA trifurcation aneurysms.


Assuntos
Aneurisma Roto , Revascularização Cerebral , Aneurisma Intracraniano , Humanos , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/cirurgia , Aneurisma Roto/diagnóstico por imagem , Aneurisma Roto/cirurgia , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/cirurgia , Revascularização Cerebral/métodos , Microcirurgia/métodos
11.
No Shinkei Geka ; 52(2): 389-398, 2024 Mar.
Artigo em Japonês | MEDLINE | ID: mdl-38514129

RESUMO

In STA-MCA bypass surgery, it is important to select the optimal recipient using preoperative simulation to avoid complications. We report a preoperative simulation for STA-MCA bypass using the Brain LAB iPLAN platform®BRAIN LAB)and the 3DCG simulation software GRID®Kompath). Here, we introduce the basics and applications of preoperative simulation for occlusive atherosclerotic lesions and present a target bypass for periventricular anastomosis and peripheral vessels of aneurysms in Moyamoya disease. By creating and visualizing 3D fusion images, the optimal donor and recipient can be selected. Determining the skin incision and extent of craniotomy according to the case is also applicable to the minimally invasive STA-MCA bypass. Preoperative simulations enable accurate pinpoint bypass surgery and prevent complications.


Assuntos
Revascularização Cerebral , Doença de Moyamoya , Humanos , Revascularização Cerebral/métodos , Artéria Cerebral Média/cirurgia , Artérias Temporais , Doença de Moyamoya/diagnóstico por imagem , Doença de Moyamoya/cirurgia , Doença de Moyamoya/complicações , Encéfalo
12.
Clin Neurol Neurosurg ; 239: 108180, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38452713

RESUMO

OBJECTIVE: Few studies have reported local hemodynamic changes after revascularization surgery. This study aimed to identify regional hemodynamic changes after combined revascularization surgery for moyamoya disease using single-photon emission computed tomography with N-isopropyl-p-123I-iodoamphetamine. METHODS: A total of 46 adults with moyamoya disease who underwent combined revascularization surgery from August 2009 to July 2021 at our facility were enrolled. The combined bypass procedure comprised a single direct bypass to the motor area and encephalo-duro-arterio-myo-synangiosis. The preoperative and postoperative cerebral blood flow (CBF) and cerebral vascular reserve (CVR) in the genu; precentral, central, parietal, angular, temporal, and posterior regions; splenium; hippocampus; and cerebellum were measured. To modify the examination variability, the cerebral-to-cerebellar activity ratio (CCR) was calculated by dividing the counts in the region by those in the cerebellum (CBF-CCR and CVR-CCR). RESULTS: Postoperatively, asymptomatic cerebral infarction occurred in three (6.5%) patients. The CBF-CCR and CVR-CCR improved in the precentral, parietal, and temporal regions and in the overall middle cerebral artery (MCA) territory. Sub-analysis of anterior cerebral artery (ACA) and posterior cerebral artery (PCA) territory hemodynamics revealed that patients with normal preoperative hemodynamics showed no changes in the CBF-CCR and CVR-CCR postoperatively, whereas patients with preoperative perfusion impairment exhibited improved CVR-CCR in the ACA territory (0.13-0.3, p=0.019) and CBF-CCR in the PCA territory (0.93-0.96, p=0.0039). CONCLUSION: Combined revascularization surgery with single bypass to the motor area improved hemodynamics in the primary targeted MCA territory and in the ACA and PCA territories among patients with preoperative hemodynamic impairment.


Assuntos
Revascularização Cerebral , Doença de Moyamoya , Adulto , Humanos , Doença de Moyamoya/diagnóstico por imagem , Doença de Moyamoya/cirurgia , Tomografia Computadorizada de Emissão de Fóton Único , Artéria Cerebral Anterior/cirurgia , Artéria Cerebral Média/cirurgia , Circulação Cerebrovascular/fisiologia , Revascularização Cerebral/métodos , Hemodinâmica
13.
PLoS One ; 19(3): e0298587, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38478550

RESUMO

Episodic increases in cerebral blood flow (CBF) are thought to contribute to improved cerebrovascular function and health. Head-out water immersion (HOWI) may be a useful modality to increase CBF secondary to the hydrostatic pressure placed on the body. However, it is unclear whether water temperatures common to the general public elicit similar cerebrovascular responses. We tested the hypothesis that mean middle cerebral artery blood velocity (MCAvmean) and cerebrovascular reactivity to CO2 (CVRCO2) would be higher during an acute bout of thermoneutral (TN; 35°C) vs. cool (COOL; 25°C) HOWI. Ten healthy participants (age: 23±3 y; 4 women) completed two randomized HOWI visits. Right MCAvmean, end-tidal CO2 (PETCO2) mean arterial pressure (MAP), and MCA conductance (MCAvmean/MAP) were continuously recorded. CVRCO2 was assessed using a stepped hypercapnia protocol before (PRE), at 30 minutes of HOWI (HOWI), immediately after HOWI (POST-1), and 45 minutes after HOWI (POST-2). Absolute values are reported as mean ± SD. MCAvmean, PETCO2, MAP, and CVRCO2 were not different between conditions at any timepoint (all P≥0.17). In COOL, MCAvmean increased from PRE (61±9 cm/s) during HOWI (68±11 cm/s), at POST-1 (69±11 cm/s), and POST-2 (72±8 cm/s) (all P<0.01), and in TN from PRE to POST-1 (66±13 vs. 71±14 cm/s; P = 0.05). PETCO2 did not change over time in either condition. In COOL, MAP increased from PRE (85±5 mmHg) during HOWI (101±4 mmHg), at POST-1 (97±7 mmHg), and POST-2 (96±9 mmHg), and in TN from PRE (88±5 mmHg) at HOWI (98±7 mmHg) and POST-1 (99±8 mmHg) (all P<0.01). In COOL, CVRCO2 increased from PRE to HOWI (1.66±0.55 vs. 1.92±0.52 cm/s/mmHg; P = 0.04). MCA conductance was not different between or within conditions. These data indicate that 30 minutes of cool HOWI augments MCAvmean and that the increase in MCAvmean persists beyond cool HOWI. However, cool HOWI does not alter CVRCO2 in healthy young adults.


Assuntos
Dióxido de Carbono , Hipercapnia , Adulto , Feminino , Humanos , Adulto Jovem , Velocidade do Fluxo Sanguíneo/fisiologia , Circulação Cerebrovascular/fisiologia , Imersão , Artéria Cerebral Média/fisiologia , Projetos Piloto , Água , Masculino
14.
CNS Neurosci Ther ; 30(2): e14584, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38421125

RESUMO

AIMS: Most studies focus on dynamic cerebral autoregulation (dCA) in the middle cerebral artery (MCA), and few studies investigated neurovascular coupling (NVC) and dCA in the posterior cerebral artery (PCA). We investigated NVC and dCA of the PCA in healthy volunteers to identify sex differences. METHODS: Thirty men and 30 age-matched women completed dCA and NCV assessments. The cerebral blood flow velocity (CBFV) and mean arterial pressure were evaluated using transcranial Doppler ultrasound and a servo-controlled plethysmograph, respectively. The dCA parameters were analyzed using transfer function analysis. The NCV was evaluated by eyes-open and eyes-closed (24 s each) periodically based on voice prompts. The eyes-open visual stimulation comprised silent reading of Beijing-related tourist information. RESULTS: The PCA gain was lower than that of the MCA in all frequency ranges (all p < 0.05). Phase was consistent across the cerebrovascular territories. The cerebrovascular conductance index (CVCi) and mean CBFV (MV) of the PCA were significantly higher during the eyes-open than eyes-closed period (CVCi: 0.50 ± 0.12 vs. 0.38 ± 0.10; MV: 42.89 ± 8.49 vs. 32.98 ± 7.25, both p < 0.001). The PCA dCA and NVC were similar between the sexes. CONCLUSION: We assessed two major mechanisms that maintain cerebral hemodynamic stability in healthy men and women. The visual stimulation-evoked CBFV of the PCA was significantly increased compared to that during rest, confirming the activation of NVC. Men and women have similar functions in PCA dCA and NCV.


Assuntos
Acoplamento Neurovascular , Humanos , Masculino , Feminino , Acoplamento Neurovascular/fisiologia , Artéria Cerebral Posterior/diagnóstico por imagem , Velocidade do Fluxo Sanguíneo/fisiologia , Homeostase/fisiologia , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/fisiologia , Ultrassonografia Doppler Transcraniana , Circulação Cerebrovascular/fisiologia , Pressão Sanguínea/fisiologia
15.
Microcirculation ; 31(3): e12849, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38354046

RESUMO

OBJECTIVE: An improved understanding of the role of the leptomeningeal collateral circulation in blood flow compensation following middle cerebral artery (MCA) occlusion can contribute to more effective treatment development for ischemic stroke. The present study introduces a model of the cerebral circulation to predict cerebral blood flow and tissue oxygenation following MCA occlusion. METHODS: The model incorporates flow regulation mechanisms based on changes in pressure, shear stress, and metabolic demand. Oxygen saturation in cerebral vessels and tissue is calculated using a Krogh cylinder model. The model is used to assess the effects of changes in oxygen demand and arterial pressure on cerebral blood flow and oxygenation after MCA occlusion. RESULTS: An increase from five to 11 leptomeningeal collateral vessels was shown to increase the oxygen saturation in the region distal to the occlusion by nearly 100%. Post-occlusion, the model also predicted a loss of autoregulation and a decrease in flow to the ischemic territory as oxygen demand was increased; these results were consistent with data from experiments that induced cerebral ischemia. CONCLUSIONS: This study highlights the importance of leptomeningeal collaterals following MCA occlusion and reinforces the idea that lower oxygen demand and higher arterial pressure improve conditions of flow and oxygenation.


Assuntos
Isquemia Encefálica , Hipertensão , Humanos , Infarto da Artéria Cerebral Média , Circulação Colateral/fisiologia , Circulação Cerebrovascular , Oxigênio , Artéria Cerebral Média
16.
J Appl Physiol (1985) ; 136(4): 707-720, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38357728

RESUMO

Fluctuating arterial blood pressure during high-intensity interval exercise (HIIE) may challenge dynamic cerebral autoregulation (dCA), specifically after stroke after an injury to the cerebrovasculature. We hypothesized that dCA would be attenuated at rest and during a sit-to-stand transition immediately after and 30 min after HIIE in individuals poststroke compared with age- and sex-matched control subjects (CON). HIIE switched every minute between 70% and 10% estimated maximal watts for 10 min. Mean arterial pressure (MAP) and middle cerebral artery blood velocity (MCAv) were recorded. dCA was quantified during spontaneous fluctuations in MAP and MCAv via transfer function analysis. For sit-to-stand, time delay before an increase in cerebrovascular conductance index (CVCi = MCAv/MAP), rate of regulation, and % change in MCAv and MAP were measured. Twenty-two individuals poststroke (age 60 ± 12 yr, 31 ± 16 mo) and twenty-four CON (age 60 ± 13 yr) completed the study. Very low frequency (VLF) gain (P = 0.02, η2 = 0.18) and normalized gain (P = 0.01, η2 = 0.43) had a group × time interaction, with CON improving after HIIE whereas individuals poststroke did not. Individuals poststroke had lower VLF phase (P = 0.03, η2 = 0.22) after HIIE compared with CON. We found no differences in the sit-to-stand measurement of dCA. Our study showed lower dCA during spontaneous fluctuations in MCAv and MAP following HIIE in individuals poststroke compared with CON, whereas the sit-to-stand response was maintained.NEW & NOTEWORTHY This study provides novel insights into poststroke dynamic cerebral autoregulation (dCA) following an acute bout of high-intensity interval exercise (HIIE). In people after stroke, dCA appears attenuated during spontaneous fluctuations in mean arterial pressure (MAP) and middle cerebral artery blood velocity (MCAv) following HIIE. However, the dCA response during a single sit-to-stand transition after HIIE showed no significant difference from controls. These findings suggest that HIIE may temporarily challenge dCA after exercise in individuals with stroke.


Assuntos
Exercício Físico , Acidente Vascular Cerebral , Adulto , Humanos , Pessoa de Meia-Idade , Idoso , Exercício Físico/fisiologia , Pressão Arterial , Homeostase/fisiologia , Artéria Cerebral Média/fisiologia , Circulação Cerebrovascular/fisiologia , Pressão Sanguínea/fisiologia , Velocidade do Fluxo Sanguíneo/fisiologia
18.
World Neurosurg ; 185: e484-e490, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38395352

RESUMO

BACKGROUND: Middle Cerebral Artery Bifurcation Aneurysm (MbifA) is associated with a high risk of rupture and poor overall prognosis in patients once it ruptures. Morphological, geometric, and hemodynamic parameters have been identified as factors contributing to the rupture of intracranial aneurysms. However, there are no studies that combine these 3 types of parameters to specifically target MbifA rupture. METHODS: This study enrolled all patients with MbifAs diagnosed at our treatment center from 1 April 2021 to 31 July 2023 who met the study criteria. All patients underwent digital subtraction angiography examination to obtain 3D rotational angiography data. We imported the complete image data into the Aneurysm/Artery Reconstruction and Analysis machine to obtain 13 morphological parameters (Dneck, Ddome, Height, Dmax, Dartery, aspect ratio [AR], size ratio, dome-neck-ratio [DNR], height-artery-ratio, bottleneck factor, Inflow Angle, Incline Angle, Arterial Angle), 5 geometric parameters (V,S,undulation index [UI], ellipticity index [EI],nonsphericity index [NSI]), and 5 hemodynamic parameters (wall shear stress [WSS], the maximum WSS, the parent artery WSS, the normalized WSS [NWSS], oscillatory shear index [OSI]). All the above significant parameters were tested by univariate and multivariate analyses to find out the independent discriminatory factors. RESULTS: A total of 49 MbifAs (16 ruptured and 33 unruptured) from 44 patients were included in the study. Height (P = 0.033), AR (P = 0.007), DNR (P = 0.011), EI (P = 0.042), NSI(P = 0.030), UI(P = 0.027), WSS(P = 0.033), and NWSS(P = 0.002) were all associated with MbifA rupture in univariate analyses, but only NWSS was an independent risk factor (P = 0.036, OR = 0.046, 95% CI: 0.003-0.815) in multivariate logistic regression analysis. CONCLUSIONS: Height, AR, DNR, EI, UI, NSI, WSS, and NWSS may be correlated with MbifA rupture, but only NWSS was an independent risk factor. A lower NWSS was associated with a higher risk of MbifA rupture. No significant differences were observed in the angle parameters, including the Inflow Angle, between ruptured and unruptured MbifAs. OSI was significantly increased at the dome of the aneurysm but the mean OSI was not found to be associated with MbifA rupture.


Assuntos
Aneurisma Roto , Hemodinâmica , Aneurisma Intracraniano , Artéria Cerebral Média , Humanos , Aneurisma Roto/diagnóstico por imagem , Feminino , Aneurisma Intracraniano/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Hemodinâmica/fisiologia , Artéria Cerebral Média/diagnóstico por imagem , Idoso , Adulto , Fatores de Risco , Angiografia Digital , Angiografia Cerebral , Imageamento Tridimensional , Estudos Retrospectivos
20.
Magn Reson Imaging ; 109: 1-9, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38417470

RESUMO

PURPOSE: Two major drawbacks of 4D-MR angiography based on superselective pseudo-continuous arterial spin labeling combined with CENTRA-keyhole and view-sharing (4D-S-PACK) are the low temporal resolution and long scanning time. We investigated the feasibility of increasing the temporal resolution and accelerating the scanning time on 4D-S-PACK by using CS-SENSE and PhyZiodynamics, a novel image-processing program that interpolates images between phases to generate new phases and reduces image noise. METHODS: Seven healthy volunteers were scanned with a 3.0 T MR scanner to visualize the internal carotid artery (ICA) system. PhyZiodynamics is a novel image-processing that interpolates images between phases to generate new phases and reduces image noise, and by increasing temporal resolution using PhyZiodynamics, inflow dynamic data (reference) were acquired by changing the labeling durations (100-2000 msec, 31 phases) in 4D-S-PACK. From this set of data, we selected seven time intervals to calculate interpolated time points with up to 61 intervals using ×10 for the generation of interpolated phases with PhyZiodynamics. In the denoising process of PhyZiodynamics, we processed the none, low, medium, high noise reduction dataset images. The time intensity curve (TIC), the contrast-to-noise ratio (CNR) were evaluated. In accelerating with CS-SENSE for 4D-S-PACK, 4D-S-PACK were scanned different SENSE or CS-SENSE acceleration factors: SENSE3, CS3-6. Signal intensity (SI), CNR, were evaluated for accelerating the 4D-S-PACK. With regard to arterial vascular visualization, we evaluated the middle cerebral artery (MCA: M1-4 segments). RESULTS: In increasing temporal resolution, the TIC showed a similar trend between the reference dataset and the interpolated dataset. As the noise reduction weight increased, the CNR of the interpolated dataset were increased compared to that of the reference dataset. In accelerating 4D-S-PACK, the SI values of the SENSE3 dataset and CS dataset with CS3-6 were no significant differences. The image noise increased with the increase of acceleration factor, and the CNR decreased with the increase of acceleration factor. Significant differences in CNR were observed between acceleration factor of SENSE3 and CS6 for the M1-4 (P < 0.05). Visualization of small arteries (M4) became less reliable in CS5 or CS6 images. Significant differences were found for the scores of M2, M3 and M4 segments between SENSE3 and CS6. CONCLUSION: With PhyZiodynamics and CS-SENSE in 4D-S-PACK, we were able to shorten the scan time while improving the temporal resolution.


Assuntos
Algoritmos , Angiografia por Ressonância Magnética , Humanos , Marcadores de Spin , Angiografia por Ressonância Magnética/métodos , Artéria Cerebral Média , Aceleração , Imageamento Tridimensional/métodos
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