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1.
Br J Radiol ; 97(1155): 567-573, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38265291

RESUMO

OBJECTIVES: To investigate electric scooter (e-scooter)-associated radiological injury incidence and distribution of injuries. METHODS: Retrospective cross-sectional study of radiological examinations related to e-scooter injuries at a major trauma centre in a small university city. The hospital radiology information system was searched for terms related to e-scooters between January 1, 2015, and October 31, 2022. E-scooter use was confirmed by review of the patients' electronic medical records. Specific injuries were divided based on site of injury using the Injury Severity Scale categorized groups. RESULTS: A total of 568 radiological studies related to e-scooter injuries were identified on 340 distinct patients (56% male, with an average age of 28 years). Peak incidence of e-scooter-related injuries was seen in the summer months, after a local scooter sharing system was introduced in October 2020. A total of 149 patients had radiologically diagnosed injuries, with extremity injuries being most frequent (80%). Facial (8%), head/neck (8%), and thorax/abdomen (4%) were less common. Radial head fractures were the most common injury (n = 27). Thirteen patients had multiple sites of injury, four of which had both upper limb and facial bone fractures described. CONCLUSIONS: We report a significant increase in radiological investigations and injuries in the context of e-scooter injuries, particularly since the introduction of an e-scooter sharing scheme. This study informs radiologists on common locations of injuries when reporting studies of patients that have had e-scooter-related injuries. ADVANCES IN KNOWLEDGE: This is the first UK-based study providing a comprehensive radiological perspective of the impact of e-scooter use and associated distribution of injuries, adding important data for many cities that are currently undertaking review of their e-scooter sharing schemes.


Assuntos
Acidentes de Trânsito , Centros de Traumatologia , Humanos , Masculino , Adulto , Feminino , Estudos Retrospectivos , Incidência , Estudos Transversais , Radiografia
2.
Alzheimers Dement ; 19(12): 5885-5904, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37563912

RESUMO

INTRODUCTION: Artificial intelligence (AI) and neuroimaging offer new opportunities for diagnosis and prognosis of dementia. METHODS: We systematically reviewed studies reporting AI for neuroimaging in diagnosis and/or prognosis of cognitive neurodegenerative diseases. RESULTS: A total of 255 studies were identified. Most studies relied on the Alzheimer's Disease Neuroimaging Initiative dataset. Algorithmic classifiers were the most commonly used AI method (48%) and discriminative models performed best for differentiating Alzheimer's disease from controls. The accuracy of algorithms varied with the patient cohort, imaging modalities, and stratifiers used. Few studies performed validation in an independent cohort. DISCUSSION: The literature has several methodological limitations including lack of sufficient algorithm development descriptions and standard definitions. We make recommendations to improve model validation including addressing key clinical questions, providing sufficient description of AI methods and validating findings in independent datasets. Collaborative approaches between experts in AI and medicine will help achieve the promising potential of AI tools in practice. HIGHLIGHTS: There has been a rapid expansion in the use of machine learning for diagnosis and prognosis in neurodegenerative disease Most studies (71%) relied on the Alzheimer's Disease Neuroimaging Initiative (ADNI) dataset with no other individual dataset used more than five times There has been a recent rise in the use of more complex discriminative models (e.g., neural networks) that performed better than other classifiers for classification of AD vs healthy controls We make recommendations to address methodological considerations, addressing key clinical questions, and validation We also make recommendations for the field more broadly to standardize outcome measures, address gaps in the literature, and monitor sources of bias.


Assuntos
Doença de Alzheimer , Doenças Neurodegenerativas , Humanos , Doença de Alzheimer/diagnóstico por imagem , Prognóstico , Inteligência Artificial , Encéfalo/diagnóstico por imagem , Neuroimagem/métodos
3.
JMIR Med Educ ; 9: e48978, 2023 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-37548997

RESUMO

BACKGROUND: ChatGPT is a large language model that has performed well on professional examinations in the fields of medicine, law, and business. However, it is unclear how ChatGPT would perform on an examination assessing professionalism and situational judgement for doctors. OBJECTIVE: We evaluated the performance of ChatGPT on the Situational Judgement Test (SJT): a national examination taken by all final-year medical students in the United Kingdom. This examination is designed to assess attributes such as communication, teamwork, patient safety, prioritization skills, professionalism, and ethics. METHODS: All questions from the UK Foundation Programme Office's (UKFPO's) 2023 SJT practice examination were inputted into ChatGPT. For each question, ChatGPT's answers and rationales were recorded and assessed on the basis of the official UK Foundation Programme Office scoring template. Questions were categorized into domains of Good Medical Practice on the basis of the domains referenced in the rationales provided in the scoring sheet. Questions without clear domain links were screened by reviewers and assigned one or multiple domains. ChatGPT's overall performance, as well as its performance across the domains of Good Medical Practice, was evaluated. RESULTS: Overall, ChatGPT performed well, scoring 76% on the SJT but scoring full marks on only a few questions (9%), which may reflect possible flaws in ChatGPT's situational judgement or inconsistencies in the reasoning across questions (or both) in the examination itself. ChatGPT demonstrated consistent performance across the 4 outlined domains in Good Medical Practice for doctors. CONCLUSIONS: Further research is needed to understand the potential applications of large language models, such as ChatGPT, in medical education for standardizing questions and providing consistent rationales for examinations assessing professionalism and ethics.

4.
Acta Neurochir (Wien) ; 165(2): 369-419, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36435931

RESUMO

BACKGROUND: Patients with the dementia subtype idiopathic normal pressure hydrocephalus (iNPH) may improve clinically following cerebrospinal fluid (CSF) diversion (shunt) surgery, though the predictors of shunt response remain debated. Currently, radiological features play an important role in the diagnosis of iNPH, but it is not well established which radiological markers most precisely predict shunt responsive iNPH. OBJECTIVE: To conduct a systematic review and meta-analysis to identify radiological predictors of shunt responsiveness, evaluate their diagnostic effectiveness, and recommend the most predictive radiological features. METHODS: Embase, MEDLINE, Scopus, PubMed, Google Scholar, and JSTOR were searched for original studies investigating radiological predictors of shunt response in iNPH patients. Included studies were assessed using the ROBINS-1 tool, and eligible studies were evaluated using a univariate meta-analysis. RESULTS: Overall, 301 full-text papers were screened, of which 28 studies were included, and 26 different radiological features were identified, 5 of these met the inclusion criteria for the meta-analysis: disproportionately enlarged subarachnoid space (DESH), callosal angle, periventricular white matter changes, cerebral blood flow (CBF), and computerized tomography cisternography. The meta-analysis showed that only callosal angle and periventricular white matter changes significantly differentiated iNPH shunt responders from non-responders, though both markers had a low diagnostic odds ratio (DOR) of 1.88 and 1.01 respectively. None of the other radiological markers differentiated shunt responsive from shunt non-responsive iNPH. CONCLUSION: Callosal angle and periventricular changes are the only diagnostically effective radiological predictors of shunt responsive iNPH patients. However, due to the DORs approximating 1, they are insufficient as sole predictors and are advised to be used only in combination with other diagnostic tests of shunt response. Future research must evaluate the combined use of multiple radiological predictors, as it may yield beneficial additive effects that may allow for more robust radiological shunt response prediction.


Assuntos
Hidrocefalia de Pressão Normal , Humanos , Hidrocefalia de Pressão Normal/diagnóstico por imagem , Hidrocefalia de Pressão Normal/cirurgia , Imageamento por Ressonância Magnética/métodos , Radiografia , Derivação Ventriculoperitoneal , Derivações do Líquido Cefalorraquidiano/métodos
5.
Mod Rheumatol Case Rep ; 7(2): 410-415, 2023 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-36562098

RESUMO

We present a case of severe juvenile dermatomyositis with limited response to steroids in an adolescent who developed symptoms within hours after receiving Pfizer BNT162b2 coronavirus disease 2019 vaccine. The patient presented with severe weakness of proximal muscles, dyspnoea, and tachycardia. His muscle enzymes were raised, and he was diagnosed with severe juvenile dermatomyositis following magnetic resonance imaging and muscle biopsy. His management was challenging, requiring multidisciplinary input, and difficult decisions with regard to the appropriate immunomodulatory treatments. The patient had to undergo escalating immunosuppressive treatments before he began to recover clinically and biochemically. To our knowledge, this is the first case in an adolescent although a few cases of similar presentations following coronavirus disease 2019 vaccination have been reported in adults. Elucidating the potential relationship of the vaccine with this severe myopathy in an adolescent is important for global vaccination policies, but avoiding the conflation of association with causation is also crucial in the context of the pandemic.


Assuntos
COVID-19 , Dermatomiosite , Doenças Musculares , Masculino , Adulto , Humanos , Adolescente , Dermatomiosite/complicações , Vacina BNT162 , Vacinas contra COVID-19 , COVID-19/complicações
6.
World Neurosurg ; 168: e546-e554, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36241140

RESUMO

BACKGROUND AND PURPOSE: Early cerebral infarction (ECI) is an independent factor associated with poor outcome following aneurysmal subarachnoid hemorrhage (aSAH). We aimed to test the association between ECI and prior global impairment of cerebral perfusion. METHODS: We performed a retrospective cohort study of consecutive patients admitted for aSAH in 2 centers. ECI was defined as any radiological cerebral infarction identified within 3 days from the onset of bleeding and not related to aneurysm repair. Global impairment of cerebral perfusion was defined as clinical or transcranial Doppler signs of brain hypoperfusion together with circulatory failure or intracranial hypertension in keeping with guidelines. The association between ECI and prior occurrence of global impairment of cerebral perfusion was tested using binary logistic regression adjusted for confounders identified in the univariate analysis. RESULTS: Seven hundred fifty-three patients with aSAH were included. ECI was observed in 40 patients (5.3%; 95% CI = 3.7%-6.9%). Prior global impairment of cerebral perfusion occurred in 90% of them (60% in-hospital) versus in 11% of patients without ECI (P < 0.001). In the multivariate analysis, World Federation of Neurological Surgeons grade (OR = 2.3, 95% CI = 1.5-3.6, P<0.001), global impairment of cerebral perfusion due to circulatory failure (OR = 4.7, 95% CI = 1.8-11, P = 0.001), or intracranial hypertension (OR = 11.1, 95% CI = 3.8-32.3, P<0.001) was an independent risk factor for ECI. CONCLUSIONS: Our study demonstrated that ECI is strongly associated with the prior occurrence of global impairment of cerebral perfusion, independent of World Federation of Neurological Surgeons grade. These patients may benefit from more intensive and systematic prevention of impaired cerebral perfusion, particularly in poor-grade patients.


Assuntos
Isquemia Encefálica , Hipertensão Intracraniana , Hemorragia Subaracnóidea , Vasoespasmo Intracraniano , Humanos , Hemorragia Subaracnóidea/complicações , Hemorragia Subaracnóidea/diagnóstico por imagem , Hemorragia Subaracnóidea/cirurgia , Estudos Retrospectivos , Infarto Cerebral/diagnóstico por imagem , Infarto Cerebral/epidemiologia , Infarto Cerebral/etiologia , Isquemia Encefálica/etiologia , Hipertensão Intracraniana/complicações , Vasoespasmo Intracraniano/complicações
7.
Interv Neuroradiol ; 28(1): 92-103, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33947251

RESUMO

The use of antiplatelets is widespread in clinical practice. However, for neurointerventional procedures, protocols for antiplatelet use are scarce and practice varies between individuals and institutions. This is further complicated by the quantity of antiplatelet agents which differ in route of administration, dosage, onset of action, efficacy and ischemic and hemorrhagic complications. Clarifying the individual characteristics for each antiplatelet agent, and their associated risks, will increasingly become relevant as the practice of mechanical thrombectomy, stenting, coiling and flow diversion procedures grows. The aim of this review is to summarize the existing literature for the use of P2Y12 inhibitors in neurointerventional procedures, examine the quality of the evidence, and highlight areas in need of further research.


Assuntos
Procedimentos Endovasculares , Procedimentos Endovasculares/métodos , Humanos , Inibidores da Agregação Plaquetária/uso terapêutico , Stents
8.
Interv Neuroradiol ; 28(1): 84-91, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33947250

RESUMO

Antiplatelet therapies are commonly used in neurointerventional procedures. However, specific guidelines for their use in these settings is lacking and it can often be difficult to balance the potential risks and benefits of these medications. Considering the continued growth and adoption of neurointerventional procedures, it is crucial to understand the properties of these agents in order to use them safely. Large-scale clinical trials are still needed to clarify many of these aspects for this emerging field. However, the existing literature already provides insight into which antiplatelet drugs are of benefit to the neurointerventionalist as well as their associated risks of ischemic and hemorrhagic complications. Hence, this review focuses on the applications of GPIIb/IIIA inhibitors to neurointerventional procedures.


Assuntos
Inibidores da Agregação Plaquetária , Complexo Glicoproteico GPIIb-IIIa de Plaquetas , Humanos , Inibidores da Agregação Plaquetária/uso terapêutico
9.
J Neurointerv Surg ; 14(11): 1107-1111, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34740985

RESUMO

BACKGROUND AND PURPOSE: Cone-beam CT angiography (CB-CTA) provides a three-dimensional spatial resolution which is, so far, unmatched in clinical practice compared with other conventional techniques such as two-dimensional digital subtracted angiography. We aimed to assess the distribution of symptomatic cerebral vasospasm following aneurysmal subarachnoid hemorrhage (aSAH) using CB-CTA. METHODS: 30 consecutive patients with aSAH undergoing vasospasm percutaneous balloon angioplasty (PBA) were recruited and underwent CB-CTA in this single-center prospective cohort series. Intracranial arteries were systematically analyzed by two independent observers from the large trunks to the distal cortical branches and perforators using a high-resolution reconstruction protocol. Intermediate and severe cerebral vasospasm was defined as 30-50% and >50% narrowing in the diameter of the vessel, respectively. RESULTS: 35 arterial cervical artery territories were analyzed, of which 80% were associated with clinical or radiological signs of delayed cerebral ischemia. The median spatial resolution was 150 µm (range 100-250 µm). Intermediate or severe vasospasm was observed in the proximal (86%, 95% CI 74% to 97%), middle (89%, 95% CI 78% to 99%), and distal (60%, 95% CI 44% to 76%) segments of the large trunks, as well as the cortical branches (11%, 95% CI 1% to 22%). No vasospasm was observed in basal ganglia or cortical perforators, or in arteries smaller than 900 µm. Vasospasm was more severe in middle or distal segments compared with proximal segments in 43% (95% CI 26% to 59%) of cases. CONCLUSIONS: Our study demonstrated that symptomatic cerebral vasospasm following aSAH did not involve arteries smaller than 900 µm, and frequently predominated in middle or distal segments. These results offer new insights into the potential management options for vasospasm using PBA.


Assuntos
Hemorragia Subaracnóidea , Vasoespasmo Intracraniano , Angiografia , Angiografia Cerebral/métodos , Angiografia por Tomografia Computadorizada , Humanos , Estudos Prospectivos , Hemorragia Subaracnóidea/complicações , Hemorragia Subaracnóidea/diagnóstico por imagem , Vasoespasmo Intracraniano/complicações , Vasoespasmo Intracraniano/etiologia
12.
Brain Commun ; 1(1): fcz013, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31886460

RESUMO

Parkinson's disease has multiple detrimental effects on motor and cognitive systems in the brain. In contrast to motor deficits, cognitive impairments in Parkinson's disease are usually not ameliorated, and can even be worsened, by dopaminergic treatments. Recent evidence has shown potential benefits from restoring other neurotransmitter deficits, including noradrenergic and serotonergic transmission. Here, we study global and regional brain network organization using task-free imaging (also known as resting-state), which minimizes performance confounds and the bias towards predetermined networks. Thirty-three patients with idiopathic Parkinson's disease were studied three times in a double-blinded, placebo-controlled counter-balanced crossover design, following placebo, 40 mg oral atomoxetine (selective noradrenaline reuptake inhibitor) or 30 mg oral citalopram (selective serotonin reuptake inhibitor). Neuropsychological assessments were performed outside the scanner. Seventy-six controls were scanned without medication to provide normative data for comparison to the patient cohort. Graph theoretical analysis of task-free brain connectivity, with a random 500-node parcellation, was used to measure the effect of disease in placebo-treated state (versus unmedicated controls) and pharmacological intervention (drug versus placebo). Relative to controls, patients on placebo had executive impairments (reduced fluency and inhibitory control), which was reflected in dysfunctional network dynamics in terms of reduced clustering coefficient, hub degree and hub centrality. In patients, atomoxetine improved fluency in proportion to plasma concentration (P = 0.006, r 2 = 0.24), and improved response inhibition in proportion to increased hub Eigen centrality (P = 0.044, r 2 = 0.14). Citalopram did not improve fluency or inhibitory control, but its influence on network integration and efficiency depended on disease severity: clustering (P = 0.01, r 2 = 0.22), modularity (P = 0.043, r 2 = 0.14) and path length (P = 0.006, r 2 = 0.25) increased in patients with milder forms of Parkinson's disease, but decreased in patients with more advanced disease (Unified Parkinson's Disease Rating Scale motor subscale part III > 30). This study supports the use of task-free imaging of brain networks in translational pharmacology of neurodegenerative disorders. We propose that hub connectivity contributes to cognitive performance in Parkinson's disease, and that noradrenergic treatment strategies can partially restore the neural systems supporting executive function.

13.
Neurobiol Aging ; 77: 169-177, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30831384

RESUMO

The presymptomatic phase of neurodegenerative diseases are characterized by structural brain changes without significant clinical features. We set out to investigate the contribution of functional network resilience to preserved cognition in presymptomatic genetic frontotemporal dementia. We studied 172 people from families carrying genetic abnormalities in C9orf72, MAPT, or PGRN. Networks were extracted from functional MRI data and assessed using graph theoretical analysis. We found that despite loss of both brain volume and functional connections, there is maintenance of an efficient topological organization of the brain's functional network in the years leading up to the estimated age of frontotemporal dementia symptom onset. After this point, functional network efficiency declines markedly. Reduction in connectedness was most marked in highly connected hub regions. Measures of topological efficiency of the brain's functional network and organization predicted cognitive dysfunction in domains related to symptomatic frontotemporal dementia and connectivity correlated with brain volume loss in frontotemporal dementia. We propose that maintaining the efficient organization of the brain's functional network supports cognitive health even as atrophy and connectivity decline presymptomatically.


Assuntos
Encéfalo/patologia , Encéfalo/fisiopatologia , Demência Frontotemporal/genética , Demência Frontotemporal/patologia , Rede Nervosa/patologia , Rede Nervosa/fisiopatologia , Adulto , Idoso , Atrofia , Encéfalo/diagnóstico por imagem , Proteína C9orf72/genética , Cognição , Feminino , Demência Frontotemporal/psicologia , Heterozigoto , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Neuroimagem , Tamanho do Órgão , Proteínas tau/genética
14.
Neurology ; 90(22): e1989-e1996, 2018 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-29703774

RESUMO

OBJECTIVE: We tested whether in vivo neuroinflammation relates to the distinctive distributions of pathology in Alzheimer disease (AD) and progressive supranuclear palsy (PSP). METHODS: Sixteen patients with symptomatic AD (including amnestic mild cognitive impairment with amyloid-positive PET scan), 16 patients with PSP-Richardson syndrome, and 13 age-, sex-, and education-matched healthy controls were included in this case-control study. Participants underwent [11C]PK11195 PET scanning, which was used as an in vivo index of neuroinflammation. RESULTS: [11C]PK11195 binding in the medial temporal lobe and occipital, temporal, and parietal cortices was increased in patients with AD, relative both to patients with PSP and to controls. Compared to controls, patients with PSP showed elevated [11C]PK11195 binding in the thalamus, putamen, and pallidum. [11C]PK11195 binding in the cuneus/precuneus correlated with episodic memory impairment in AD, while [11C]PK11195 binding in the pallidum, midbrain, and pons correlated with disease severity in PSP. CONCLUSIONS: Together, our results suggest that neuroinflammation has an important pathogenic role in the 2 very different human neurodegenerative disorders of AD and PSP. The increase and distribution of microglial activation suggest that immunotherapeutic strategies may be useful in slowing the progression of both diseases.


Assuntos
Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Encefalite/metabolismo , Paralisia Supranuclear Progressiva/metabolismo , Doença de Alzheimer/complicações , Doença de Alzheimer/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Radioisótopos de Carbono/administração & dosagem , Encefalite/complicações , Encefalite/diagnóstico por imagem , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Paralisia Supranuclear Progressiva/complicações , Paralisia Supranuclear Progressiva/diagnóstico por imagem
15.
Brain ; 141(2): 550-567, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-29293892

RESUMO

Alzheimer's disease and progressive supranuclear palsy (PSP) represent neurodegenerative tauopathies with predominantly cortical versus subcortical disease burden. In Alzheimer's disease, neuropathology and atrophy preferentially affect 'hub' brain regions that are densely connected. It was unclear whether hubs are differentially affected by neurodegeneration because they are more likely to receive pathological proteins that propagate trans-neuronally, in a prion-like manner, or whether they are selectively vulnerable due to a lack of local trophic factors, higher metabolic demands, or differential gene expression. We assessed the relationship between tau burden and brain functional connectivity, by combining in vivo PET imaging using the ligand AV-1451, and graph theoretic measures of resting state functional MRI in 17 patients with Alzheimer's disease, 17 patients with PSP, and 12 controls. Strongly connected nodes displayed more tau pathology in Alzheimer's disease, independently of intrinsic connectivity network, validating the predictions of theories of trans-neuronal spread but not supporting a role for metabolic demands or deficient trophic support in tau accumulation. This was not a compensatory phenomenon, as the functional consequence of increasing tau burden in Alzheimer's disease was a progressive weakening of the connectivity of these same nodes, reducing weighted degree and local efficiency and resulting in weaker 'small-world' properties. Conversely, in PSP, unlike in Alzheimer's disease, those nodes that accrued pathological tau were those that displayed graph metric properties associated with increased metabolic demand and a lack of trophic support rather than strong functional connectivity. Together, these findings go some way towards explaining why Alzheimer's disease affects large scale connectivity networks throughout cortex while neuropathology in PSP is concentrated in a small number of subcortical structures. Further, we demonstrate that in PSP increasing tau burden in midbrain and deep nuclei was associated with strengthened cortico-cortical functional connectivity. Disrupted cortico-subcortical and cortico-brainstem interactions meant that information transfer took less direct paths, passing through a larger number of cortical nodes, reducing closeness centrality and eigenvector centrality in PSP, while increasing weighted degree, clustering, betweenness centrality and local efficiency. Our results have wide-ranging implications, from the validation of models of tau trafficking in humans to understanding the relationship between regional tau burden and brain functional reorganization.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/metabolismo , Conectoma/métodos , Paralisia Supranuclear Progressiva/diagnóstico por imagem , Paralisia Supranuclear Progressiva/metabolismo , Proteínas tau/metabolismo , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/patologia , Compostos de Anilina/farmacocinética , Mapeamento Encefálico , Carbolinas/farmacocinética , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Vias Neurais/diagnóstico por imagem , Oxigênio/sangue , Tomografia por Emissão de Pósitrons , Descanso , Paralisia Supranuclear Progressiva/patologia , Tiazóis/farmacocinética
17.
Brain ; 140(3): 781-791, 2017 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-28122879

RESUMO

The ability to assess the distribution and extent of tau pathology in Alzheimer's disease and progressive supranuclear palsy in vivo would help to develop biomarkers for these tauopathies and clinical trials of disease-modifying therapies. New radioligands for positron emission tomography have generated considerable interest, and controversy, in their potential as tau biomarkers. We assessed the radiotracer 18F-AV-1451 with positron emission tomography imaging to compare the distribution and intensity of tau pathology in 15 patients with Alzheimer's pathology (including amyloid-positive mild cognitive impairment), 19 patients with progressive supranuclear palsy, and 13 age- and sex-matched controls. Regional analysis of variance and a support vector machine were used to compare and discriminate the clinical groups, respectively. We also examined the 18F-AV-1451 autoradiographic binding in post-mortem tissue from patients with Alzheimer's disease, progressive supranuclear palsy, and a control case to assess the 18F-AV-1451 binding specificity to Alzheimer's and non-Alzheimer's tau pathology. There was increased 18F-AV-1451 binding in multiple regions in living patients with Alzheimer's disease and progressive supranuclear palsy relative to controls [main effect of group, F(2,41) = 17.5, P < 0.0001; region of interest × group interaction, F(2,68) = 7.5, P < 0.00001]. More specifically, 18F-AV-1451 binding was significantly increased in patients with Alzheimer's disease, relative to patients with progressive supranuclear palsy and with control subjects, in the hippocampus and in occipital, parietal, temporal, and frontal cortices (t's > 2.2, P's < 0.04). Conversely, in patients with progressive supranuclear palsy, relative to patients with Alzheimer's disease, 18F-AV-1451 binding was elevated in the midbrain (t = 2.1, P < 0.04); while patients with progressive supranuclear palsy showed, relative to controls, increased 18F-AV-1451 uptake in the putamen, pallidum, thalamus, midbrain, and in the dentate nucleus of the cerebellum (t's > 2.7, P's < 0.02). The support vector machine assigned patients' diagnoses with 94% accuracy. The post-mortem autoradiographic data showed that 18F-AV-1451 strongly bound to Alzheimer-related tau pathology, but less specifically in progressive supranuclear palsy. 18F-AV-1451 binding to the basal ganglia was strong in all groups in vivo. Postmortem histochemical staining showed absence of neuromelanin-containing cells in the basal ganglia, indicating that off-target binding to neuromelanin is an insufficient explanation of 18F-AV-1451 positron emission tomography data in vivo, at least in the basal ganglia. Overall, we confirm the potential of 18F-AV-1451 as a heuristic biomarker, but caution is indicated in the neuropathological interpretation of its binding. Off-target binding may contribute to disease profiles of 18F-AV-1451 positron emission tomography, especially in primary tauopathies such as progressive supranuclear palsy. We suggest that 18F-AV-1451 positron emission tomography is a useful biomarker to assess tau pathology in Alzheimer's disease and to distinguish it from other tauopathies with distinct clinical and pathological characteristics such as progressive supranuclear palsy.


Assuntos
Doença de Alzheimer/diagnóstico por imagem , Encéfalo/diagnóstico por imagem , Carbolinas/farmacocinética , Paralisia Supranuclear Progressiva/diagnóstico por imagem , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/complicações , Autopsia , Autorradiografia , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Estudos de Casos e Controles , Transtornos Cognitivos/diagnóstico por imagem , Transtornos Cognitivos/etiologia , Feminino , Fluordesoxiglucose F18/farmacocinética , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Tomografia por Emissão de Pósitrons/métodos , Ligação Proteica/efeitos dos fármacos , Escalas de Graduação Psiquiátrica , Paralisia Supranuclear Progressiva/complicações , Proteínas tau/metabolismo
19.
Neuropsychopharmacology ; 41(8): 2171-7, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26837463

RESUMO

Cognitive impairment is common in Parkinson's disease (PD), but often not improved by dopaminergic treatment. New treatment strategies targeting other neurotransmitter deficits are therefore of growing interest. Imaging the brain at rest ('task-free') provides the opportunity to examine the impact of a candidate drug on many of the brain networks that underpin cognition, while minimizing task-related performance confounds. We test this approach using atomoxetine, a selective noradrenaline reuptake inhibitor that modulates the prefrontal cortical activity and can facilitate some executive functions and response inhibition. Thirty-three patients with idiopathic PD underwent task-free fMRI. Patients were scanned twice in a double-blind, placebo-controlled crossover design, following either placebo or 40-mg oral atomoxetine. Seventy-six controls were scanned once without medication to provide normative data. Seed-based correlation analyses were used to measure changes in functional connectivity, with the right inferior frontal gyrus (IFG) a critical region for executive function. Patients on placebo had reduced connectivity relative to controls from right IFG to dorsal anterior cingulate cortex and to left IFG and dorsolateral prefrontal cortex. Atomoxetine increased connectivity from the right IFG to the dorsal anterior cingulate. In addition, the atomoxetine-induced change in connectivity from right IFG to dorsolateral prefrontal cortex was proportional to the change in verbal fluency, a simple index of executive function. The results support the hypothesis that atomoxetine may restore prefrontal networks related to executive functions. We suggest that task-free imaging can support translational pharmacological studies of new drug therapies and provide evidence for engagement of the relevant neurocognitive systems.


Assuntos
Inibidores da Captação Adrenérgica/administração & dosagem , Cloridrato de Atomoxetina/administração & dosagem , Doença de Parkinson/fisiopatologia , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/fisiopatologia , Idoso , Mapeamento Encefálico , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Vias Neurais/efeitos dos fármacos , Vias Neurais/fisiopatologia
20.
Neurorehabil Neural Repair ; 29(5): 444-52, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25326511

RESUMO

BACKGROUND AND OBJECTIVE: Mirror therapy is a new form of stroke rehabilitation that uses the mirror reflection of the unaffected hand in place of the affected hand to augment movement training. The mechanism of mirror therapy is not known but is thought to involve changes in cerebral organization. We used magnetoencephalography (MEG) to measure changes in cortical activity during mirror training after stroke. In particular, we examined movement-related changes in the power of cortical oscillations in the beta (15-30 Hz) frequency range, known to be involved in movement. METHODS: Ten stroke patients with upper limb paresis and 13 healthy controls were recorded using MEG while performing bimanual hand movements in 2 different conditions. In one, subjects looked directly at their affected hand (or dominant hand in controls), and in the other, they looked at a mirror reflection of their unaffected hand in place of their affected hand. The movement-related beta desynchronization was calculated in both primary motor cortices. RESULTS: Movement-related beta desynchronization was symmetrical during bilateral movement and unaltered by the mirror condition in controls. In the patients, movement-related beta desynchronization was generally smaller than in controls, but greater in contralesional compared to ipsilesional motor cortex. This initial asymmetry in movement-related beta desynchronization between hemispheres was made more symmetrical by the presence of the mirror. CONCLUSIONS: Mirror therapy could potentially aid stroke rehabilitation by normalizing an asymmetrical pattern of movement-related beta desynchronization in primary motor cortices during bilateral movement.


Assuntos
Córtex Cerebral/fisiopatologia , Imagens, Psicoterapia/métodos , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Reabilitação do Acidente Vascular Cerebral , Adulto , Idoso , Análise de Variância , Feminino , Lateralidade Funcional , Humanos , Imageamento por Ressonância Magnética , Magnetoencefalografia , Masculino , Pessoa de Meia-Idade , Análise Espectral
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