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BACKGROUND: The diagnosis and prognosis of diffuse axonal injury (DAI) remain challenging. This research aimed to analyze the impact on activities of daily living (ADL), functional outcomes, quality of life (QoL), and the association between lesion severity and DAI location identified through imaging exams. METHODS: This prospective cohort study included 95 patients diagnosed with DAI. Data were collected at admission, three, six, and twelve months post-injury. The associations between variables were evaluated using a mixed-effects model. RESULTS: Functional recovery and QoL improved between three and twelve months after DAI. An interaction was observed between independence in performing ADL and subarachnoid hemorrhage (p = 0.043) and intraventricular hemorrhage (p = 0.012). Additionally, an interaction over time was observed between the Glasgow Outcome Scale (GOS) and DAI severity (p < 0.001), brain lesions (p = 0.014), and the Disability Rating Scale (DRS) with injury in brain hemispheres (p = 0.026) and Adams classification (p = 0.013). Interaction effects over time were observed with the general health perceptions and energy/vitality domains with intraventricular hemorrhage, and the social functioning domain with the obliteration of basal cisterns and Gentry's classification. CONCLUSION: The use of CT in the acute phase of DAI is important for predicting outcomes. The severity and location of DAI are associated with functional outcomes, ADL, and QoL.
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Resumen La proteína precursora del β- Amiloide (β-APP) es una glicoproteína de membrana y un componente habitual de las neuronas. Tiene funciones en el crecimiento y la adhesión celular tras un traumatismo. Es transportada mediante transporte rápido axonal anterógrado y se acumula dentro de las neuronas cuando se daña citoesqueleto. Este proceso es activo, es decir consume energía. El β-APP no es específico de los traumatismos. Se acumula en cualquier circunstancia en la que se dañen los axones, tal como la hipoxia, alteraciones metabólicas, y cualquier otra causa de edema cerebral y aumento de la presión intracraneal que puedan conducir a un daño axonal difuso (DAI) En el presente estudio estudiamos la expresión de esta proteína en casos de traumatismo cráneo-encefálico con diferente evolución cronológica El daño del citoesqueleto producido por la proteólisis, junto con la alteración de las quinasas y las fosfatasas, aumentan la permeabilidad de la membrana, lo que provoca la entrada de calcio en la célula que, a su vez, activa la calmodulina que hace que los neurofilamentos se compacten, los microtúbulos desaparezcan y se rompa la espectrina. Esta disrupción del citoesqueleto tiene como consecuencia que las sustancias que se transportan a su través, se acumulen, sobre todo en las zonas afectadas por el DAI. Al final de todo este proceso, los axones se rompen, lo que se conoce como axotomía secundaria. El estudio de la acumulación del β-APP es útil para valorar la extensión del DAI y para determinar el tiempo de supervivencia tras el traumatismo o cualquier otro daño cerebral.
Abstract β-Amyloid Precursor Protein (β-APP) is a membrane glycoprotein and a common component of neurons. It is involved in adhesion and cell growth processes after traumatic events. It is carried by anterograde fast axonal transport, and it accumulates inside neurons when the cytoskeleton is damaged. This is a vital biochemical process that consumes energy. β-APP is not specific of traumatic events. It accumulates in any case of axonal damage, whatever its cause may be, like hypoxia, metabolic disorders, and any other circumstances that lead to brain swelling and intracranial pressure rising and in consequence to Diffuse Axonal Injury (DAI). In this study we review the expression of this protein in cases of traumatic brain injury with different chronological evolution. The damage of cytoskeleton due to proteolysis in addition to the disturbance of kinases and phosphatases increase the permeability of the membrane. Calcium gets into the cell and activates calmodulin, thus neurofilaments compact, microtubules disappear and spectrin breaks. This disruption of the cytoskeleton has as consequence that the transported substances accumulate in the most affected areas by DAI. At the end of this process axon breaks, which is known as secondary axotomy. The study of the accumulation of β-APP is useful to assess the extent of DAI and to determine the time elapsed after trauma or another insult to CNS.
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Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Peptídeos beta-Amiloides/química , Lesão Axonal Difusa , Traumatismos Craniocerebrais , Medicina LegalRESUMO
BACKGROUND: Diffuse axonal injury (DAI) is a frequent mechanism of traumatic brain injury (TBI) that triggers a sequence of parenchymal changes that progresses from focal axonal shear injuries up to inflammatory response and delayed axonal disconnection. OBJECTIVE: The main purpose of this study is to evaluate changes in the axonal/myelinic content and the brain volume up to 12 months after TBI and to correlate these changes with neuropsychological results. METHODS: Patients with DAI (n = 25) were scanned at three time points after trauma (2, 6, and 12 months), and the total brain volume (TBV), gray matter volume, and white matter volume (WMV) were calculated in each time point. The magnetization transfer ratio (MTR) for the total brain (TB MTR), gray matter (GM MTR), and white matter (WM MTR) was also quantified. In addition, Hopkins verbal learning test (HVLT), Trail Making Test (TMT), and Rey-Osterrieth Complex Figure test were performed at 6 and 12 months after the trauma. RESULTS: There was a significant reduction in the mean TBV, WMV, TB MTR, GM MTR, and WM MTR between time points 1 and 3 (p < .05). There was also a significant difference in HVLT-immediate, TMT-A, and TMT-B scores between time points 2 and 3. The MTR decline correlated more with the cognitive dysfunction than the volume reduction. CONCLUSION: A progressive axonal/myelinic rarefaction and volume loss were characterized, especially in the white matter (WM) up to 1 year after the trauma. Despite that, specific neuropsychological tests revealed that patients' episodic verbal memory, attention, and executive function improved during the study. The current findings may be valuable in developing long-term TBI rehabilitation management programs.
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Lesões Encefálicas Traumáticas , Lesão Axonal Difusa , Encéfalo/diagnóstico por imagem , Lesões Encefálicas Traumáticas/complicações , Lesões Encefálicas Traumáticas/diagnóstico por imagem , Cognição , Lesão Axonal Difusa/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Testes NeuropsicológicosRESUMO
BACKGROUND: Neuropsychological rehabilitation is a crucial component of medical care for patients with diffuse axonal injury (DAI). However, current cognitive intervention programs directed to favor the training of specific domains individually have shown controversial results. Here, we evaluated the effectiveness of a neuropsychological rehabilitation program directed to favor training of attention, memory, visuospatial abilities, and executive functioning together in a patient with severe traumatic brain injury (TBI)-associated DAI. CASE PRESENTATION: A 26-year-old Hispanic woman with a recent history of a severe TBI attended our center complaining of memory problems, dysarthria, and difficulty in planning. A comprehensive cognitive assessment revealed dysfunction in sustained, selective, and divided attention, alterations in memory, planning, and organization of executive behavior, as well as impairment of visuospatial cognitive functions. The patient underwent a 24-week neuropsychological rehabilitation program directed to favor attention, memory, visuospatial abilities, and executive functioning together. After the cognitive intervention, we observed a better patient's performance in tasks requiring sustained, selective, and divided attention, improvement of encoding and retrieval memory problems, use of spatial relationships, planning, and organization of behavior skills. We also observed generalization effects on other domains, such as learning, mental flexibility, inhibition functions, and language. CONCLUSIONS: In conclusion, our results suggest that neuropsychological rehabilitation programs favoring multiple domains together are useful in reestablishing cognitive deficits in patients with severe DAI.
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Lesões Encefálicas Traumáticas , Transtornos Cognitivos , Lesão Axonal Difusa , Adulto , Lesões Encefálicas Traumáticas/complicações , Cognição , Transtornos Cognitivos/etiologia , Lesão Axonal Difusa/complicações , Função Executiva , Feminino , Humanos , Testes NeuropsicológicosRESUMO
Paroxysmal sympathetic hyperactivity may appear after brain injury. Its clinical manifestations are sporadic and self-limited crisis of arterial hypertension, hyperthermia, tachycardia, hyperhidrosis, muscle tension, sialorrhea and mydriasis. These subside with the administration of morphine and beta-blockers. It may be caused by a dysautonomia leading to increased levels of catecholamines due to the lack of brain regulation. We report a 19 years-old man with a history of illicit drug and alcohol consumption, with a secondary axonal injury due to a cranioencephalic trauma. During hospitalization, he had recurrent, self-limited episodes of dysautonomia. An infectious cause was discarded. When morphine was administrated suspecting the presence of pain, the crisis subsided, which helped to establish the diagnosis of paroxysmal sympathetic hyperactivity.
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Humanos , Masculino , Adulto , Sistema Nervoso Simpático/patologia , Encéfalo/diagnóstico por imagem , Hemorragia/etiologia , Sistema Nervoso Simpático/diagnóstico por imagem , Imageamento por Ressonância MagnéticaRESUMO
PURPOSE: Diffuse axonal injury (DAI) is the rupture of multiple axons due to acceleration and deceleration forces during a closed head injury. Most traumatic brain injuries (TBI) have some degree of DAI, especially severe TBI. Computed tomography (CT) remains the first imaging test performed in the acute phase of TBI, but has low sensitivity for detecting DAI, since DAI is a cellular lesion. The aim of this study is to search in the literature for CT signs, in the first 24 h after TBI, that may help to differentiate patients in groups with a better versus worst prognosis. METHODS: We searched for primary scientific articles in the PubMed database, in English, indexed since January 1st, 2000. RESULTS: Five articles were selected for review. In the DAI group, traffic accidents accounted 70% of the cases, 79% were male, and the mean age was 41 years. There was an association between DAI and intraventricular hemorrhage (IVH) and traumatic subarachnoid hemorrhage (tSAH); an association between the IVH grade and number of corpus callosum lesions; and an association between blood in the interpeduncular cisterns (IPC) and brainstem lesions. CONCLUSION: In closed TBI with no tSAH, severe DAI is unlikely. Similarly, in the absence of IVH, any DAI is unlikely. If there is IVH, patients generally are clinically worse; and the more ventricles affected, the worse the prognosis.
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Lesão Axonal Difusa/diagnóstico por imagem , Lesão Axonal Difusa/etiologia , Tomografia Computadorizada por Raios X , Acidentes de Trânsito , Tronco Encefálico/lesões , Hemorragia Cerebral Traumática/diagnóstico por imagem , Hemorragia Cerebral Traumática/etiologia , Hemorragia Cerebral Intraventricular/diagnóstico por imagem , Hemorragia Cerebral Intraventricular/etiologia , Corpo Caloso/lesões , Humanos , Prognóstico , Hemorragia Subaracnóidea/diagnóstico por imagem , Hemorragia Subaracnóidea/etiologiaRESUMO
The present review paper aims to update the definition and classification of cerebral concussion, highlighting its pathophysiological mechanisms. The high prevalence of cerebral concussion in emergency rooms around the world makes it necessary to know its proper management to avoid its late sequelae, which traditionally compromise cognitive aspects of behavior. New evidence on potential neuroprotective treatments is being investigated.
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Concussão Encefálica/classificação , Concussão Encefálica/diagnóstico , Concussão Encefálica/fisiopatologia , Concussão Encefálica/tratamento farmacológico , Concussão Encefálica/epidemiologiaRESUMO
We report a case of traumatic brain injury treated with Cerebrolysin, a neurorecovery stimulating agent. Our therapeutic approach was based on the pathophysiology of traumatic brain injury and, in particular, of diffuse axonal injury. The patient registered marked improvement in mood and cognitive performance, indicating the effectiveness of multimodal and multidisciplinary interventions after traumatic brain injury.
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Acidentes de Trânsito , Aminoácidos/uso terapêutico , Lesão Axonal Difusa/tratamento farmacológico , Velocidade do Fluxo Sanguíneo , Lesões Encefálicas Traumáticas/tratamento farmacológico , Lesões Encefálicas Traumáticas/fisiopatologia , Lesão Axonal Difusa/fisiopatologia , Humanos , Masculino , Adulto JovemRESUMO
Diffuse axonal injury (DAI) is an important consequence of traumatic brain injury (TBI). At the moment of trauma, axons rarely disconnect, but undergo cytoskeletal disruption and transport interruption leading to protein accumulation within swellings. The amyloid precursor protein (APP) accumulates rapidly and the standard histological evaluation of axonal pathology relies upon its detection. APP+ swellings first appear as varicosities along intact axons, which can ultimately undergo secondary disconnection to leave a terminal "axon bulb" at the disconnected, proximal end. However, sites of disconnection are difficult to determine with certainty using standard, thin tissue sections, thus limiting the comprehensive evaluation of axon degeneration. The tissue-clearing technique, CLARITY, permits three-dimensional visualization of axons that would otherwise be out of plane in standard tissue sections. Here, we examined the morphology and connection status of APP+ swellings using CLARITY at 6 h, 24 h, 1 week and 1 month following the controlled cortical impact (CCI) model of TBI in mice. Remarkably, many APP+ swellings that appeared as terminal bulbs when viewed in standard 8-µm-thick regions of tissue were instead revealed to be varicose swellings along intact axons when three dimensions were fully visible. Moreover, the percentage of these potentially viable axon swellings differed with survival from injury and may represent the delayed onset of distinct mechanisms of degeneration. Even at 1-month post-CCI, ~10% of apparently terminal bulbs were revealed as connected by CLARITY and are thus potentially salvageable. Intriguingly, the diameter of swellings decreased with survival, including varicosities along intact axons, and may reflect reversal of, or reduced, axonal transport interruption in the chronic setting. These data indicate that APP immunohistochemistry on standard thickness tissue sections overestimates axon disconnection, particularly acutely post-injury. Evaluating cleared tissue demonstrates a surprisingly delayed process of axon disconnection and thus longer window of therapeutic opportunity than previously appreciated. Intriguingly, a subset of axon swellings may also be capable of recovery.
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Lesão Axonal Difusa/patologia , Técnicas Histológicas/métodos , Imuno-Histoquímica/métodos , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Transporte Axonal , Axônios/patologia , Encéfalo/patologia , Lesões Encefálicas/patologia , Lesões Encefálicas Traumáticas/complicações , Lesões Encefálicas Traumáticas/fisiopatologia , Lesão Axonal Difusa/metabolismo , Modelos Animais de Doenças , Masculino , Camundongos , Camundongos EndogâmicosRESUMO
BACKGROUND AND OBJECTIVE: Diffuse axonal injury (DAI) induces a long-term process of brain atrophy and cognitive deficits. The goal of this study was to determine whether there are correlations between brain volume loss, microhaemorrhage load (MHL) and neuropsychological performance during the first year after DAI. METHODS: Twenty-four patients with moderate or severe DAI were evaluated at 2, 6 and 12 months post-injury. MHL was evaluated at 3 months, and brain volumetry was evaluated at 3, 6 and 12 months. The trail making test (TMT) was used to evaluate executive function (EF), and the Hopkins verbal learning test (HVLT) was used to evaluate episodic verbal memory (EVM) at 6 and 12 months. RESULTS: There were significant white matter volume (WMV), subcortical grey matter volume and total brain volume (TBV) reductions during the study period (p < 0.05). MHL was correlated only with WMV reduction. EF and EVM were not correlated with MHL but were, in part, correlated with WMV and TBV reductions. CONCLUSIONS: Our findings suggest that MHL may be a predictor of WMV reduction but cannot predict EF or EVM in DAI. Brain atrophy progresses over time, but patients showed better EF and EVM in some of the tests, which could be due to neuroplasticity.
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Encéfalo/diagnóstico por imagem , Transtornos Cognitivos/etiologia , Lesão Axonal Difusa/complicações , Lesão Axonal Difusa/diagnóstico por imagem , Adolescente , Adulto , Atenção/fisiologia , Transtornos Cognitivos/diagnóstico por imagem , Função Executiva , Feminino , Escala de Coma de Glasgow , Humanos , Processamento de Imagem Assistida por Computador , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Tomógrafos Computadorizados , Aprendizagem Verbal , Substância Branca/diagnóstico por imagem , Adulto JovemRESUMO
The cost of traumatic brain injury (TBI) for public health policies is undeniable today. Even patients who suffer from mild TBI may persist with cognitive symptoms weeks after the accident. Most of them show no lesion in computed tomography or conventional magnetic resonance imaging, but microstructural white matter abnormalities (diffuse axonal lesion) can be found in diffusion tensor imaging. Different brain networks work together to form an important part of the cognition process, and they can be affected by TBI. The default mode network (DMN) plays an important central role in normal brain activities, presenting greater relative deactivation during more cognitively demanding tasks. After deactivation, it allows a distinct network to activate. This network (the central executive network) acts mainly during tasks involving executive functions. The salience network is another network necessary for normal executive function, and its activation leads to deactivation of the DMN. The use of red or near-infrared (NIR) light to stimulate or regenerate tissue is known as photobiomodulation. It was discovered that NIR (wavelength 800-900 nm) and red (wavelength 600 nm) light-emitting diodes (LEDs) are able to penetrate through scalp and skull and have the potential to improve the subnormal, cellular activity of compromised brain tissue. Based on this, different experimental and clinical studies were done to test LED therapy for TBI, and promising results were found. It leads us to consider developing different approaches to maximize the positive effects of this therapy and improve the quality of life of TBI patients.
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BACKGROUND: Overactivation of NMDA-mediated excitatory processes and excess of GABA-mediated inhibition are attributed to the acute and subacute phases, respectively, after a traumatic brain injury (TBI). However, there are few studies regarding the circuitry during the chronic phase of brain injury. OBJECTIVE: To evaluate the cortical excitability (CE) during the chronic phase of TBI in victims diagnosed with diffuse axonal injury (DAI). METHODS: The 22 adult subjects were evaluated after a minimum of 1 year from the onset of moderate or severe TBI. Each of the subjects first had a comprehensive neuropsychological assessment to evaluate executive functions-attention, memory, verbal fluency, and information processing speed. Then, CE assessment was performed with a circular coil applying single-pulse and paired-pulse transcranial magnetic stimulation over the cortical representation of the abductor pollicis brevis muscle on M1 of both hemispheres. The CE parameters measured were resting motor threshold (RMT), motor-evoked potentials (MEPs), short-interval intracortical inhibition (SIICI), and intracortical facilitation (ICF). All data were compared with that of a control group that consisted of the healthy age-matched individuals. RESULTS: No significant differences between the left and right hemispheres were detected in the DAI subjects. Therefore, parameters were analyzed as pooled data. Values of RMT, MEPs, and ICF from DAI patients were within normal limits. However, SIICI values were higher in the DAI group-DAI SIICI = 1.28 (1.01; 1.87) versus the control value = 0.56 (0.33; 0.69)-suggesting that they had a disarranged inhibitory system (p < 0.001). By contrast, the neuropsychological findings had weak correlation with the CE data. CONCLUSION: As inhibition processes involve GABA-mediated circuitry, it is likely that the DAI pathophysiology itself (disruption of axons) may deplete GABA and contribute to ongoing disinhibition of these neural circuits of the cerebrum during the chronic phase of DAI.
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BACKGROUND: Photobiomodulation describes the use of red or near-infrared light to stimulate or regenerate tissue. It was discovered that near-infrared wavelengths (800-900 nm) and red (600 nm) light-emitting diodes (LED) are able to penetrate through the scalp and skull and have the potential to improve the subnormal cellular activity of compromised brain tissue. Different experimental and clinical studies were performed to test LED therapy for traumatic brain injury (TBI) with promising results. One of the proposals of this present study is to develop different approaches to maximize the positive effects of this therapy and improve the quality of life of TBI patients. METHODS/DESIGN: This is a double-blinded, randomized, controlled trial of patients with diffuse axonal injury (DAI) due to a severe TBI in an acute stage (less than 8 h). Thirty two patients will be randomized to active coil helmet and inactive coil (sham) groups in a 1:1 ratio. The protocol includes 18 sessions of transcranial LED stimulation (627 nm, 70 mW/cm2, 10 J/cm2) at four points of the frontal and parietal regions for 30 s each, totaling 120 s, three times per week for 6 weeks, lasting 30 min. Patients will be evaluated with the Glasgow Outcome Scale Extended (GOSE) before stimulation and 1, 3, and 6 months after the first stimulation. The study hypotheses are as follows: (1) transcranial LED therapy (TCLT) will improve the cognitive function of DAI patients and (2) TCLT will promote beneficial hemodynamic changes in cerebral circulation. DISCUSSION: This study evaluates early and delayed effects of TCLT on the cognitive rehabilitation for DAI following severe acute TBI. There is a paucity of studies regarding the use of this therapy for cognitive improvement in TBI. There are some experimental studies and case series presenting interesting results for TBI cognitive improvement but no clinical trials. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03281759 . Registered on 13 September 2017.
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Lesões Encefálicas Traumáticas/radioterapia , Encéfalo/efeitos da radiação , Cognição/efeitos da radiação , Lesão Axonal Difusa/radioterapia , Lasers Semicondutores/uso terapêutico , Terapia com Luz de Baixa Intensidade/instrumentação , Adolescente , Adulto , Encéfalo/irrigação sanguínea , Encéfalo/fisiopatologia , Lesões Encefálicas Traumáticas/diagnóstico , Lesões Encefálicas Traumáticas/fisiopatologia , Lesões Encefálicas Traumáticas/psicologia , Brasil , Circulação Cerebrovascular/efeitos da radiação , Lesão Axonal Difusa/diagnóstico , Lesão Axonal Difusa/fisiopatologia , Lesão Axonal Difusa/psicologia , Método Duplo-Cego , Feminino , Escala de Coma de Glasgow , Humanos , Lasers Semicondutores/efeitos adversos , Terapia com Luz de Baixa Intensidade/efeitos adversos , Masculino , Pessoa de Meia-Idade , Exame Neurológico , Qualidade de Vida , Ensaios Clínicos Controlados Aleatórios como Assunto , Recuperação de Função Fisiológica , Fatores de Tempo , Resultado do Tratamento , Adulto JovemRESUMO
ABSTRACT Traumatic brain injury (TBI) is the number one cause of death and morbidity among young adults. Moreover, survivors are frequently left with functional disabilities during the most productive years of their lives. One main aspect of TBI pathology is diffuse axonal injury, which is increasingly recognized due to its presence in 40% to 50% of all cases that require hospital admission. Diffuse axonal injury is defined as widespread axonal damage and is characterized by complete axotomy and secondary reactions due to overall axonopathy. These changes can be seen in neuroimaging studies as hemorrhagic focal areas and diffuse edema. However, the diffuse axonal injury findings are frequently under-recognized in conventional neuroimaging studies. In such scenarios, diffuse tensor imaging (DTI) plays an important role because it provides further information on white matter integrity that is not obtained with standard magnetic resonance imaging sequences. Extensive reviews concerning the physics of DTI and its use in the context of TBI patients have been published, but these issues are still hazy for many allied-health professionals. Herein, we aim to review the current contribution of diverse state-of-the-art DTI analytical methods to the understanding of diffuse axonal injury pathophysiology and prognosis, to serve as a quick reference for those interested in planning new studies and who are involved in the care of TBI victims. For this purpose, a comprehensive search in Pubmed was performed using the following keywords: "traumatic brain injury", "diffuse axonal injury", and "diffusion tensor imaging".
RESUMO O traumatismo cranioencefálico (TCE) é a principal causa de morbimortalidade entre adultos jovens. Aqueles que sobrevivem são frequentemente deixados com sequelas funcionais nos anos mais produtivos de suas vidas. O principal aspecto fisiopatológico do TCE é a lesão axonial difusa (LAD), cada vez mais destacada pois está presente em 40 a 50% dos casos que necessitam de internação hospitalar. LAD é definida como a injúria axonial extensa caracterizada pela axoniotomia completa assim como pelas reações secundárias a axoniopatia, que são demonstradas por métodos de neuroimagem como áreas de edema e micro-hemorragia. Entretanto, os achados da LAD são frequentemente subestimados em estudos de neuroimagem convencional. É neste contexto que imagens por tensor de difusão (DTI) ganharam ênfase, já que permitem obter informações sobre a integridade da substância branca que não eram obtidas por sequências convencionais de ressonância magnética (RM). Existem artigos extensos sobre os fundamentos físicos e as aplicações de DTI em pacientes vítimas de TCE, no entanto, estes assuntos permanecem ainda nebulosos a alguns profissionais da área de saúde. Deste modo, propomos uma revisão didática sobre a contribuição do estado da arte de diferentes métodos analíticos de DTI no entendimento do processo da fisiopatologia e prognóstico da LAD, servindo assim como uma ferramenta acessível para aqueles interessados em planejamento de novos estudos e aqueles envolvidos no tratamento de vítimas de TCE. Uma pesquisa abrangente foi realizada no Pubmed com as seguintes palavras-chave: "traumatismo cranioencefálico", "lesão axonial difusa", "imagem por tensor de difusão".
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Humanos , Masculino , Feminino , Lesão Axonal Difusa/diagnóstico por imagem , Imagem de Tensor de Difusão/métodos , Valores de Referência , Mapeamento Encefálico/métodos , Imageamento por Ressonância Magnética/métodos , Índices de Gravidade do Trauma , Reprodutibilidade dos Testes , Anisotropia , Lesão Axonal Difusa/fisiopatologia , Substância Branca/lesõesRESUMO
Objectives To determine the relationship between alcohol consumption and the incidence of traumatic brain injury (TBI) with diffuse axonal injury (DAI), determining these indices, checking acquired comorbidities and characterizing the patients by gender, age and race/color, as well as describing the characteristics of the motor vehicle collision (vehicle, period of the day, day of the week and site) in people admitted to an emergency hospital in the city of Teresina, in the state of Piauí, Brazil. Methods We have analyzed the data contained in the medical records of patients admitted with a history of motor vehicle collision and severe TBI in intensive care units, based on the forms provided by the Mobile Emergency Care Service (SAMU, in the Portuguese acronym) in the period between February 28 and November 28, 2013. Results In the period covered by the present study, 200 individuals were analyzed, and 54 (27%) had consumed alcohol; of these 11 had DAI. Of the total sample, 17% (34) presented DAI, however, with unknown data regarding the consumption of alcoholic beverages. Conclusion Considering the data, we observed that the profile of the head trauma patients are brown men, mostly (53.5%) aged between 15 and 30 years. The collisions occurred mostly on weekends and at night (55%), and 89.5% of the crashes involved motorcycles.
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Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Adulto Jovem , Consumo de Bebidas Alcoólicas/epidemiologia , Acidentes de Trânsito/estatística & dados numéricos , Lesão Axonal Difusa/epidemiologia , Lesões Encefálicas Traumáticas/epidemiologia , Fatores de Tempo , Brasil/epidemiologia , Consumo de Bebidas Alcoólicas/efeitos adversos , Prontuários Médicos , Epidemiologia Descritiva , Interpretação Estatística de Dados , Lesões Encefálicas Traumáticas/etiologiaRESUMO
Diffuse axonal injury (DAI) is a hallmark of traumatic brain injury (TBI) pathology. Recently, the Closed Head Injury Model of Engineered Rotational Acceleration (CHIMERA) was developed to generate an experimental model of DAI in a mouse. The characterization of DAI using diffusion tensor magnetic resonance imaging (MRI; diffusion tensor imaging, DTI) may provide a useful set of outcome measures for preclinical and clinical studies. The objective of this study was to identify the complex neurobiological underpinnings of DTI features following DAI using a comprehensive and quantitative evaluation of DTI and histopathology in the CHIMERA mouse model. A consistent neuroanatomical pattern of pathology in specific white matter tracts was identified across ex vivo DTI maps and photomicrographs of histology. These observations were confirmed by voxelwise and regional analysis of DTI maps, demonstrating reduced fractional anisotropy (FA) in distinct regions such as the optic tract. Similar regions were identified by quantitative histology and exhibited axonal damage as well as robust gliosis. Additional analysis using a machine-learning algorithm was performed to identify regions and metrics important for injury classification in a manner free from potential user bias. This analysis found that diffusion metrics were able to identify injured brains almost with the same degree of accuracy as the histology metrics. Good agreement between regions detected as abnormal by histology and MRI was also found. The findings of this work elucidate the complexity of cellular changes that give rise to imaging abnormalities and provide a comprehensive and quantitative evaluation of the relative importance of DTI and histological measures to detect brain injury.
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Lesão Axonal Difusa/diagnóstico por imagem , Lesão Axonal Difusa/etiologia , Imagem de Difusão por Ressonância Magnética , Traumatismos Cranianos Fechados/complicações , Aceleração/efeitos adversos , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Anisotropia , Proteínas de Ligação ao Cálcio/metabolismo , Lesão Axonal Difusa/patologia , Modelos Animais de Doenças , Proteína Glial Fibrilar Ácida/metabolismo , Traumatismos Cranianos Fechados/etiologia , Processamento de Imagem Assistida por Computador , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas dos Microfilamentos/metabolismo , Trato Óptico/patologiaRESUMO
Wallerian degeneration (WD) is defined as progressive anterograde disintegration of axons and accompanying demyelination after an injury to the proximal axon or cell body. Since the 1980s and 1990s, conventional magnetic resonance imaging (MRI) sequences have been shown to be sensitive to changes of WD in the subacute to chronic phases. More recently, advanced MRI techniques, such as diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI), have demonstrated some of earliest changes attributed to acute WD, typically on the order of days. In addition, there is increasing evidence on the value of advanced MRI techniques in providing important prognostic information related to WD. This article reviews the utility of conventional and advanced MRI techniques for assessing WD, by focusing not only on the corticospinal tract but also other neural tracts less commonly thought of, including corticopontocerebellar tract, dentate-rubro-olivary pathway, posterior column of the spinal cord, corpus callosum, limbic circuit, and optic pathway. The basic anatomy of these neural pathways will be discussed, followed by a comprehensive review of existing literature supported by instructive clinical examples. The goal of this review is for readers to become more familiar with both conventional and advanced MRI findings of WD involving important neural pathways, as well as to illustrate increasing utility of advanced MRI techniques in providing important prognostic information for various pathologies.