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Precisely how the anatomical structure of the brain gives rise to a repertoire of complex functions remains incompletely understood. A promising manifestation of this mapping from structure to function is the dependency of the functional activity of a brain region on the underlying white matter architecture. Here, we review the literature examining the macroscale coupling between structural and functional connectivity, and we establish how this structure-function coupling (SFC) can provide more information about the underlying workings of the brain than either feature alone. We begin by defining SFC and describing the computational methods used to quantify it. We then review empirical studies that examine the heterogeneous expression of SFC across different brain regions, among individuals, in the context of the cognitive task being performed, and over time, as well as its role in fostering flexible cognition. Last, we investigate how the coupling between structure and function is affected in neurological and psychiatric conditions, and we report how aberrant SFC is associated with disease duration and disease-specific cognitive impairment. By elucidating how the dynamic relationship between the structure and function of the brain is altered in the presence of neurological and psychiatric conditions, we aim to not only further our understanding of their aetiology but also establish SFC as a new and sensitive marker of disease symptomatology and cognitive performance. Overall, this Review collates the current knowledge regarding the regional interdependency between the macroscale structure and function of the human brain in both neurotypical and neuroatypical individuals.
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Diffusion-weighted magnetic resonance imaging (dMRI) is the primary method for noninvasively studying the organization of white matter in the human brain. Here we introduce QSIPrep, an integrative software platform for the processing of diffusion images that is compatible with nearly all dMRI sampling schemes. Drawing on a diverse set of software suites to capitalize on their complementary strengths, QSIPrep facilitates the implementation of best practices for processing of diffusion images.
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Encéfalo/diagnóstico por imagem , Imagem de Difusão por Ressonância Magnética/métodos , Processamento de Imagem Assistida por Computador/métodos , Software , Humanos , Linguagens de Programação , Fluxo de TrabalhoRESUMO
The field of network neuroscience has emerged as a natural framework for the study of the brain and has been increasingly applied across divergent problems in neuroscience. From a disciplinary perspective, network neuroscience originally emerged as a formal integration of graph theory (from mathematics) and neuroscience (from biology). This early integration afforded marked utility in describing the interconnected nature of neural units, both structurally and functionally, and underscored the relevance of that interconnection for cognition and behavior. But since its inception, the field has not remained static in its methodological composition. Instead, it has grown to use increasingly advanced graph-theoretic tools and to bring in several other disciplinary perspectives-including machine learning and systems engineering-that have proven complementary. In doing so, the problem space amenable to the discipline has expanded markedly. In this review, we discuss three distinct flavors of investigation in state-of-the-art network neuroscience: (i) descriptive network neuroscience, (ii) predictive network neuroscience, and (iii) a perturbative network neuroscience that draws on recent advances in network control theory. In considering each area, we provide a brief summary of the approaches, discuss the nature of the insights obtained, and highlight future directions.
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Neurociências , Encéfalo , Cognição , Previsões , HumanosRESUMO
This article reports two cases of patients with coronavirus disease 2019 (COVID-19) in which occlusion of large cerebral arteries occurred. These occurred in a female patient in the early stage of COVID-19 and in the second case in the late stage. One female patient could be successfully treated with i.v. thrombolysis and mechanical thrombectomy. Coagulopathy in the course of COVID-19 can result in severe stroke with poor outcome even in younger patients. With respect to the etiology of arterial occlusions (COVID-19-induced hypercoagulopathy, cardiomyopathy, vasculitis) there is a necessity for further research.
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Isquemia Encefálica , COVID-19 , AVC Isquêmico , Acidente Vascular Cerebral , Feminino , Humanos , SARS-CoV-2 , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/terapia , Trombectomia , Terapia Trombolítica , Resultado do TratamentoRESUMO
Background and Purpose- We aimed to explore the association between presence of cerebral cortical microinfarcts (CMIs) on magnetic resonance imaging and other small-vessel disease neuroimaging biomarkers in cerebral amyloid angiopathy (CAA) and to analyze the role of CMIs on individual cognitive domains and dementia conversion. Methods- Participants were recruited from an ongoing longitudinal research cohort of eligible CAA patients between March 2006 and October 2016. A total of 102 cases were included in the analysis that assessed the relationship of cortical CMIs to CAA neuroimaging markers. Ninety-five subjects had neuropsychological tests conducted within 1 month of magnetic resonance imaging scanning. Seventy-five nondemented CAA patients had cognitive evaluation data available during follow-up. Results- Among 102 patients enrolled, 40 patients had CMIs (39%) on magnetic resonance imaging. CMIs were uniformly distributed throughout the cortex without regional predilection ( P=0.971). The presence of CMIs was associated with lower total brain volume (odds ratio, 0.85; 95% CI, 0.74-0.98; P=0.025) and presence of cortical superficial siderosis (odds ratio, 2.66; 95% CI, 1.10-6.39; P=0.029). In 95 subjects with neuropsychological tests, presence of CMIs was associated with impaired executive function (ß, -0.23; 95% CI, -0.44 to -0.02; P=0.036) and processing speed (ß, -0.24; 95% CI, -0.45 to -0.04; P=0.020). Patients with CMIs had a higher cumulative dementia incidence compared with patients without CMIs ( P=0.043), whereas only baseline total brain volume (hazard ratio, 0.76; 95% CI, 0.62-0.92; P=0.006) independently predicted dementia conversion. Conclusions- Magnetic resonance imaging-detected CMIs in CAA correlated with greater overall disease burden. The presence of CMIs was associated with worse cognitive performance, whereas only total brain atrophy independently predicted dementia conversion.
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Angiopatia Amiloide Cerebral/diagnóstico por imagem , Cognição/fisiologia , Processamento de Imagem Assistida por Computador , Neuroimagem , Idoso , Idoso de 80 Anos ou mais , Córtex Cerebral/patologia , Função Executiva/fisiologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Neuroimagem/métodos , Testes NeuropsicológicosRESUMO
BACKGROUND AND PURPOSE: We evaluated whether lacunes in centrum semiovale (lobar lacunes) were associated with cerebral amyloid angiopathy (CAA) markers in an Asian intracerebral hemorrhage (ICH) population. METHODS: One hundred ten patients with primary ICH were classified as CAA-ICH (n=24; mean age, 70.9±13.9) or hypertensive ICH (n=86; mean age, 59.3±13.0) according to the presence of strictly lobar (per modified Boston criteria) or strictly deep bleeds (both ICH and cerebral microbleeds), respectively. Lacunes were evaluated in the supratentorial area and classified as lobar or classical deep based on the location. A subgroup of 36 patients also underwent Pittsburgh Compound B positron emission tomography to measure cerebral amyloid deposition and global standardized uptake value ratio were calculated. RESULTS: Lobar lacunes were more frequent in CAA-ICH than hypertensive ICH (29.2 versus 11.6%; P=0.036). In multivariable models, lobar lacunes were associated with lobar cerebral microbleed (odds ratio, 6.8; 95% confidence interval, 1.6-29.9; P=0.011) after adjustment for age, sex, hypertension, and white matter hyperintensity. In 15 CAA-ICH and 21 hypertensive ICH patients with Pittsburgh Compound B positron emission tomography, correlation analyses between lobar lacune counts and global standardized uptake value ratio showed positive association (ρ=0.40; P=0.02) and remained significant after adjustment for age (r=0.34; P=0.04). CONCLUSIONS: Our findings expand on recent work showing that lobar lacunes are more frequent in CAA-ICH than hypertensive ICH. Their independent association with lobar cerebral microbleeds and brain amyloid deposition suggests a relationship with CAA even in an Asian cohort with overall higher hypertensive load.
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Angiopatia Amiloide Cerebral/diagnóstico por imagem , Hemorragia Cerebral/diagnóstico por imagem , Imageamento por Ressonância Magnética , Acidente Vascular Cerebral Lacunar/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Angiopatia Amiloide Cerebral/complicações , Hemorragia Cerebral/complicações , Diagnóstico Diferencial , Feminino , Humanos , Hemorragia Intracraniana Hipertensiva/diagnóstico por imagem , Hemorragia Intracraniana Hipertensiva/fisiopatologia , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Acidente Vascular Cerebral Lacunar/complicaçõesRESUMO
INTRODUCTION: Acute non-traumatic convexity subarachnoid haemorrhage (cSAH) is increasingly recognised in cerebral amyloid angiopathy (CAA). We investigated: (a) the overlap between acute cSAH and cortical superficial siderosis-a new CAA haemorrhagic imaging signature and (b) whether acute cSAH presents with particular clinical symptoms in patients with probable CAA without lobar intracerebral haemorrhage. METHODS: MRI scans of 130 consecutive patients meeting modified Boston criteria for probable CAA were analysed for cortical superficial siderosis (focal, ≤3 sulci; disseminated, ≥4 sulci), and key small vessel disease markers. We compared clinical, imaging and cortical superficial siderosis topographical mapping data between subjects with versus without acute cSAH, using multivariable logistic regression. RESULTS: We included 33 patients with probable CAA presenting with acute cSAH and 97 without cSAH at presentation. Patients with acute cSAH were more commonly presenting with transient focal neurological episodes (76% vs 34%; p<0.0001) compared with patients with CAA without cSAH. Patients with acute cSAH were also more often clinically presenting with transient focal neurological episodes compared with cortical superficial siderosis-positive, but cSAH-negative subjects with CAA (76% vs 30%; p<0.0001). Cortical superficial siderosis prevalence (but no other CAA severity markers) was higher among patients with cSAH versus those without, especially disseminated cortical superficial siderosis (49% vs 19%; p<0.0001). In multivariable logistic regression, cortical superficial siderosis burden (OR 5.53; 95% CI 2.82 to 10.8, p<0.0001) and transient focal neurological episodes (OR 11.7; 95% CI 2.70 to 50.6, p=0.001) were independently associated with acute cSAH. CONCLUSIONS: This probable CAA cohort provides additional evidence for distinct disease phenotypes, determined by the presence of cSAH and cortical superficial siderosis.
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Encéfalo/diagnóstico por imagem , Angiopatia Amiloide Cerebral/diagnóstico por imagem , Córtex Cerebral/diagnóstico por imagem , Siderose/diagnóstico por imagem , Hemorragia Subaracnóidea/diagnóstico por imagem , Idoso , Angiopatia Amiloide Cerebral/epidemiologia , Hemorragia Cerebral/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Prevalência , Siderose/epidemiologia , Hemorragia Subaracnóidea/epidemiologiaRESUMO
Patients with cerebral amyloid angiopathy (CAA) show loss of white matter connectivity and cortical thinning on MRI, primarily in posterior brain regions. Here we examined whether a potential causal relationship exists between these markers of subcortical and cortical brain injury by examining whether changes in cortical thickness progress in tandem with changes in their underlying connections. Thirty-one patients with probable CAA with brain MRI at two time points were included (follow-up time: 1.3 ± 0.4 years). Brain networks were reconstructed using diffusion MRI-based fiber tractography. Of each network node, we calculated the change in fractional anisotropy-weighted connectivity strength over time and the change in cortical thickness. The association between change in connectivity strength and cortical thickness was assessed with (hierarchical) linear regression models. Our results showed that decline in posterior network connectivity over time was strongly related to thinning of the occipital cortex (ß = 0.65 (0.35-0.94), P < 0.001), but not to thinning of the other posterior or frontal cortices. However, at the level of individual network nodes, we found no association between connectivity strength and cortical thinning of the corresponding node (ß = 0.009 ± 0.04, P = 0.80). Associations were independent of age, sex, and other brain MRI markers of CAA. To conclude, CAA patients with greater progressive loss of posterior white matter connectivity also have greater progression of occipital cortical thinning, but our results do not support a direct causal relationship between them. The association can be better explained by a shared underlying mechanism, which may form a potential target for future treatments. Hum Brain Mapp 38:3723-3731, 2017. © 2017 Wiley Periodicals, Inc.
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BACKGROUND AND PURPOSE: We recently showed that cerebral amyloid angiopathy (CAA) is associated with functionally relevant brain network impairments, in particular affecting posterior white matter connections. Here we examined how these brain network impairments progress over time. METHODS: Thirty-three patients with probable CAA underwent multimodal brain magnetic resonance imaging at 2 time points (mean follow-up time: 1.3±0.4 years). Brain networks of the hemisphere free of intracerebral hemorrhages were reconstructed using fiber tractography and graph theory. The global efficiency of the network and mean fractional anisotropies of posterior-posterior, frontal-frontal, and posterior-frontal network connections were calculated. Patients with moderate versus severe CAA were defined based on microbleed count, dichotomized at the median (median=35). RESULTS: Global efficiency of the intracerebral hemorrhage-free hemispheric network declined from baseline to follow-up (-0.008±0.003; P=0.029). The decline in global efficiency was most pronounced for patients with severe CAA (group×time interaction P=0.03). The decline in global network efficiency was associated with worse executive functioning (ß=0.46; P=0.03). Examination of subgroups of network connections revealed a decline in fractional anisotropies of posterior-posterior connections at both levels of CAA severity (-0.006±0.002; P=0.017; group×time interaction P=0.16). The fractional anisotropies of posterior-frontal and frontal-frontal connections declined in patients with severe but not moderate CAA (group×time interaction P=0.007 and P=0.005). Associations were independent of change in white matter hyperintensity volume. CONCLUSIONS: Brain network impairment in patients with CAA worsens measurably over just 1.3-year follow-up and seem to progress from posterior to frontal connections with increasing disease severity.
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Encéfalo/patologia , Angiopatia Amiloide Cerebral/patologia , Hemorragia Cerebral/patologia , Transtornos Cognitivos/patologia , Rede Nervosa/patologia , Idoso , Encéfalo/diagnóstico por imagem , Angiopatia Amiloide Cerebral/diagnóstico por imagem , Hemorragia Cerebral/diagnóstico por imagem , Transtornos Cognitivos/diagnóstico por imagem , Progressão da Doença , Função Executiva/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Memória/fisiologia , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Testes NeuropsicológicosRESUMO
Central brain network connections greatly contribute to overall network efficiency. Here we examined whether small vessel disease (SVD) related white matter alterations in central brain network connections have a greater impact on executive functioning than alterations in non-central brain network connections. Brain networks were reconstructed from diffusion-weighted MRI scans in 72 individuals (75 ± 8 years) with cognitive impairment and SVD on MRI. The centrality of white matter connections in the network was defined using graph theory. The association between the fractional anisotropy (FA) of central versus non-central connections, executive functioning, and markers of SVD was evaluated with linear regression and mediation analysis. Lower FA in central network connections was more strongly associated with impairment in executive functioning than FA in non-central network connections (r = 0.41 vs. r = 0.27; P < 0.05). Results were consistent across varying thresholds to define the central subnetwork (>50%-10% connections). Higher SVD burden was associated with lower FA in central as well as non-central network connections. However, only central network FA mediated the relationship between white matter hyperintensity volume and executive functioning [change in regression coefficient after mediation (95% CI): -0.15 (-0.35 to -0.02)]. The mediation effect was not observed for FA alterations in non-central network connections [-0.03 (-0.19 to 0.04)]. These findings suggest that the centrality of network connections, and thus their contribution to global network efficiency, appears to be relevant for understanding the relationship between SVD and cognitive impairment. Hum Brain Mapp 37:2446-2454, 2016. © 2016 Wiley Periodicals, Inc.
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Encéfalo/diagnóstico por imagem , Doenças de Pequenos Vasos Cerebrais/diagnóstico por imagem , Doenças de Pequenos Vasos Cerebrais/psicologia , Disfunção Cognitiva/diagnóstico por imagem , Idoso , Doenças de Pequenos Vasos Cerebrais/complicações , Cognição , Disfunção Cognitiva/etiologia , Imagem de Difusão por Ressonância Magnética , Imagem de Tensor de Difusão , Função Executiva , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Modelos Lineares , Estudos Longitudinais , Masculino , Vias Neurais/diagnóstico por imagem , Tamanho do Órgão , Substância Branca/diagnóstico por imagemRESUMO
Cerebral amyloid angiopathy is a common form of small-vessel disease and an important risk factor for cognitive impairment. The mechanisms linking small-vessel disease to cognitive impairment are not well understood. We hypothesized that in patients with cerebral amyloid angiopathy, multiple small spatially distributed lesions affect cognition through disruption of brain connectivity. We therefore compared the structural brain network in patients with cerebral amyloid angiopathy to healthy control subjects and examined the relationship between markers of cerebral amyloid angiopathy-related brain injury, network efficiency, and potential clinical consequences. Structural brain networks were reconstructed from diffusion-weighted magnetic resonance imaging in 38 non-demented patients with probable cerebral amyloid angiopathy (69 ± 10 years) and 29 similar aged control participants. The efficiency of the brain network was characterized using graph theory and brain amyloid deposition was quantified by Pittsburgh compound B retention on positron emission tomography imaging. Global efficiency of the brain network was reduced in patients compared to controls (0.187 ± 0.018 and 0.201 ± 0.015, respectively, P < 0.001). Network disturbances were most pronounced in the occipital, parietal, and posterior temporal lobes. Among patients, lower global network efficiency was related to higher cortical amyloid load (r = -0.52; P = 0.004), and to magnetic resonance imaging markers of small-vessel disease including increased white matter hyperintensity volume (P < 0.001), lower total brain volume (P = 0.02), and number of microbleeds (trend P = 0.06). Lower global network efficiency was also related to worse performance on tests of processing speed (r = 0.58, P < 0.001), executive functioning (r = 0.54, P = 0.001), gait velocity (r = 0.41, P = 0.02), but not memory. Correlations with cognition were independent of age, sex, education level, and other magnetic resonance imaging markers of small-vessel disease. These findings suggest that reduced structural brain network efficiency might mediate the relationship between advanced cerebral amyloid angiopathy and neurologic dysfunction and that such large-scale brain network measures may represent useful outcome markers for tracking disease progression.
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Encéfalo/patologia , Angiopatia Amiloide Cerebral/complicações , Doenças do Sistema Nervoso/etiologia , Doenças do Sistema Nervoso/patologia , Vias Neurais/patologia , Idoso , Análise de Variância , Transtornos Cognitivos/etiologia , Estudos de Coortes , Estudos Transversais , Imagem de Tensor de Difusão , Feminino , Lateralidade Funcional , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Modelos NeurológicosRESUMO
BACKGROUND AND PURPOSE: Cerebral microinfarcts (CMI) are important contributors to vascular cognitive impairment. Magnetic resonance imaging diffusion-weighted imaging (DWI) hyperintensities have been suggested to represent acute CMI. We aim to describe a mathematical method for estimating total number of CMI based on the presence of incidental DWI lesions. METHODS: We reviewed magnetic resonance imaging scans of subjects with cognitive decline, cognitively normal subjects and previously reported subjects with past intracerebral hemorrhage (ICH). Based on temporal and spatial characteristics of DWI lesions, we estimated the annual rate of CMI needed to explain the observed rate of DWI lesion detection in each group. To confirm our estimates, we performed extensive sampling for CMI in the brain of a deceased subject with past lobar ICH who found to have a DWI lesion during life. RESULTS: Clinically silent DWI lesions were present in 13 of 343 (3.8%) cognitively impaired and 10 of 199 (5%) cognitively intact normal non-ICH patients, both lower than the incidence in the past ICH patients (23 of 178; 12.9%; P<0.0006). The predicted annual incidence of CMI ranges from 16 to 1566 for non-ICH and 50 to 5041 for ICH individuals. Histological sampling revealed a total of 60 lesions in 32 sections. Based on previously reported methods, this density of CMI yields an estimated total brain burden maximum likelihood estimate of 9321 CMIs (95% confidence interval, 7255-11 990). CONCLUSIONS: Detecting even a single DWI lesion suggests an annual incidence of hundreds of new CMI. The cumulative effects of these lesions may directly contribute to small-vessel-related vascular cognitive impairment.
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Infarto Cerebral/diagnóstico , Infarto Cerebral/metabolismo , Imagem de Difusão por Ressonância Magnética/métodos , Microcirculação , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Estudos Transversais , Imagem de Difusão por Ressonância Magnética/normas , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos RetrospectivosRESUMO
BACKGROUND AND PURPOSE: We sought to identify baseline determinants of the anatomic pattern of hematoma expansion in patients with intracerebral hemorrhage and spot sign. METHODS: We coregistered baseline and follow-up CT scans from 15 intracerebral hemorrhage patients and measured growth at each surface node from baseline to follow-up hematoma. We analyzed the effects of proximity to the spot sign or hematoma center on distance of expansion, controlling for covariates. RESULTS: There was substantial node-to-node variation in the extent of expansion around each hematoma surface (mean coefficient of variation for expansion distance, 0.43; 95% confidence interval, 0.39-0.48), indicating nonuniform expansion. Closer proximity to the hematoma center was independently associated with increased expansion (0.185 mm greater expansion for each 1 mm closer to the center; P<0.0001). Closer proximity to the spot sign was not independently associated with increased expansion in models including both terms. CONCLUSIONS: Hemorrhages expand nonuniformly around their surface with a tendency for greater expansion closer to their center. These findings provide a novel framework for analyzing mechanisms underlying hemorrhage growth and response to treatment.
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Angiografia Cerebral/métodos , Hemorragia Cerebral/diagnóstico por imagem , Hemorragia Cerebral/fisiopatologia , Hematoma/diagnóstico por imagem , Hematoma/fisiopatologia , Tomografia Computadorizada por Raios X/métodos , Idoso , Idoso de 80 Anos ou mais , Hemorragia Cerebral/patologia , Progressão da Doença , Feminino , Seguimentos , Hematoma/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos RetrospectivosRESUMO
Introduction Multinodular goiter (MNG) is a common thyroid disorder characterized by the presence of multiple nodules within the thyroid gland. While most cases of MNG are benign, there is a risk of malignancy, particularly in nodules with certain features. The coexistence of occult (latent) thyroid cancer within MNG presents diagnostic and management challenges, underscoring the need for comprehensive investigation and treatment strategies. Objective The objective of this retrospective study is to investigate the prevalence of occult thyroid carcinoma in non-toxic MNG following total thyroidectomy. Materials and methods The study population consisted of 412 patients who underwent total thyroidectomy between 2004 and 2022 at the Second Surgical Department of the 424 General Military Hospital of Education in Thessaloniki. Data collection included patients' demographic characteristics, surgical indications for thyroidectomy, and histopathological examination findings. Initial data were available for all 412 patients, while sufficient information was present for 319 individuals, with a subset of 271 undergoing total thyroidectomy due to non-toxic MNG. Out of the aforementioned group, 253 cases were histologically confirmed as MNG. Subsequently, a statistical analysis was conducted concerning age, gender, the association of MNG with malignancy, and other thyroid disorders. Results Out of the total 412 thyroidectomies performed, 271 patients remained for statistical analysis and study. Among them, 253 patients had histologically confirmed MNG. Among the histological findings, 38 cases (14.02%) were identified with occult carcinoma within MNG. The predominant histological type was papillary thyroid carcinoma (PTC), comprising 93.3% of cases. Additionally, 18 patients (6.64%) were diagnosed with MNG, Hashimoto's thyroiditis (HT), and malignancy concurrently. Conclusions The coexistence of occult thyroid carcinoma within MNG underscores the importance of vigilant evaluation and management strategies in patients undergoing total thyroidectomy. These findings emphasize the need for comprehensive preoperative assessment and postoperative surveillance to detect and address occult thyroid cancer, thereby optimizing patient care and outcomes.
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The coproliths of the appendix are accumulations of fecal remnants within its lumen. They are categorized based on their size into coproliths < 1cm, which are the most common, and giant coproliths, with a diameter > 2cm. It's important to note that the pathophysiology of acute appendicitis is characterized by the obstruction of the appendix lumen. This leads to distension due to the inability to expel secretions, ischemia, and ultimately rupture of its wall. This presentation discusses an interesting case of acute appendicitis caused by a giant coprolith. It also covers the clinical approach and information according to international literature. A 38-year-old man presented with sudden-onset right lower quadrant pain. Clinical examination revealed tenderness, a positive McBurney's point, elevated inflammation markers, and a radiopaque finding on an X-ray. A CT scan revealed a 2.5cm coprolith in the appendix. An exploratory laparoscopy revealed appendix wall rupture, followed by subumbilical incision appendicectomy and cleansing of purulent collection. The patient was discharged from the hospital on the fourth postoperative day without any complications, demonstrating a smooth recovery process. The presence of a coprolith predisposes the development of acute appendicitis. This condition is associated with a worse prognosis, as it increases the likelihood of perforation and the formation of intraperitoneal abscesses. This case underscores the clinical significance of giant coproliths as a potential etiology for acute appendicitis. Early recognition and timely surgical intervention are pivotal in achieving favorable patient outcomes.
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Foreign body ingestion is a common reason for emergency department (ED) visits, with rare complications necessitating immediate surgical intervention. This case report discusses diagnosis and treatment, emphasizing the importance of prompt intervention. A 45-year-old male with dentures presented with acute left abdominal pain. Diagnostic tests identified a foreign body in the descending colon, leading to laparoscopic surgery. Early laparoscopy offers a safe and reliable alternative to exploratory laparotomy. This case underscores the significance of swift diagnosis, preventing severe complications like peritonitis, obstruction, and hemorrhage. In conclusion, while foreign body ingestion is common, intestinal perforation remains extremely rare. Physicians should consider it in their differential diagnosis, with computed tomography (CT) and rapid surgical intervention as crucial components of proper management.
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Recent work has demonstrated that the relationship between structural and functional connectivity varies regionally across the human brain, with reduced coupling emerging along the sensory-association cortical hierarchy. The biological underpinnings driving this expression, however, remain largely unknown. Here, we postulate that intracortical myelination and excitation-inhibition (EI) balance mediate the heterogeneous expression of structure-function coupling (SFC) and its temporal variance across the cortical hierarchy. We employ atlas- and voxel-based connectivity approaches to analyze neuroimaging data acquired from two groups of healthy participants. Our findings are consistent across six complementary processing pipelines: 1) SFC and its temporal variance respectively decrease and increase across the unimodal-transmodal and granular-agranular gradients; 2) increased myelination and lower EI-ratio are associated with more rigid SFC and restricted moment-to-moment SFC fluctuations; 3) a gradual shift from EI-ratio to myelination as the principal predictor of SFC occurs when traversing from granular to agranular cortical regions. Collectively, our work delivers a framework to conceptualize structure-function relationships in the human brain, paving the way for an improved understanding of how demyelination and/or EI-imbalances induce reorganization in brain disorders.
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Encéfalo , Córtex Cerebral , Humanos , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiologia , Lobo Parietal , Neuroimagem , Inibição Psicológica , Imageamento por Ressonância MagnéticaRESUMO
Myelination is a key developmental process that promotes rapid and efficient information transfer. Myelin also stabilizes existing brain networks and thus may constrain neuroplasticity, defined here as the brain's potential to change in response to experiences rather than the canonical definition as the process of change. Characterizing individual differences in neuroplasticity may shed light on mechanisms by which early experiences shape learning, brain and body development, and response to interventions. The T1-weighted/T2-weighted (T1w/T2w) MRI signal ratio is a proxy measure of cortical microstructure and thus neuroplasticity. Here, in pre-registered analyses, we investigated individual differences in T1w/T2w ratios in children (ages 4-10, n = 157). T1w/T2w ratios were positively associated with age within early-developing sensorimotor and attention regions. We also tested whether socioeconomic status, cognition (crystallized knowledge or fluid reasoning), and biological age (as measured with molar eruption) were related to T1w/T2w signal but found no significant effects. Associations among T1w/T2w ratios, early experiences, and cognition may emerge later in adolescence and may not be strong enough to detect in moderate sample sizes.
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Encéfalo , Individualidade , Criança , Adolescente , Humanos , Imageamento por Ressonância Magnética , Cabeça , Bainha de MielinaRESUMO
Delineation of tumor margins is a critical and challenging objective during brain cancer surgery. A tumor-targeting deep-blue nanoparticle-based visible contrast agent is described, which, for the first time, offers in vivo tumor-specific visible color staining. This technology thus enables color-guided tumor resection in real time, with no need for extra equipment or special lighting conditions. The visual contrast agent consists of polyacrylamide nanoparticles covalently linked to Coomassie Blue molecules (for nonleachable blue color contrast), which are surface-conjugated with polyethylene glycol and F3 peptides for efficient in vivo circulation and tumor targeting, respectively.
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Neoplasias Encefálicas/patologia , Cirurgia Geral , Hidrogéis , Nanopartículas , Corantes de Rosanilina/química , Humanos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Células Tumorais Cultivadas , Recursos HumanosRESUMO
Precisely how the anatomical structure of the brain supports a wide range of complex functions remains a question of marked importance in both basic and clinical neuroscience. Progress has been hampered by the lack of theoretical frameworks explaining how a structural network of relatively rigid interareal connections can produce a diverse repertoire of functional neural dynamics. Here, we address this gap by positing that the brain's structural network architecture determines the set of accessible functional connectivity patterns according to predictions of network control theory. In a large developmental cohort of 823 youths aged 8 to 23 years, we found that the flexibility of a brain region's functional connectivity was positively correlated with the proportion of its structural links extending to different cognitive systems. Notably, this relationship was mediated by nodes' boundary controllability, suggesting that a region's strategic location on the boundaries of modules may underpin the capacity to integrate information across different cognitive processes. Broadly, our study provides a mechanistic framework that illustrates how temporal flexibility observed in functional networks may be mediated by the controllability of the underlying structural connectivity.