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1.
J Nucl Med ; 65(5): 670-678, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38514082

RESUMO

Since the development of amyloid tracers for PET imaging, there has been interest in quantifying amyloid burden in the brains of patients with Alzheimer disease. Quantitative amyloid PET imaging is poised to become a valuable approach in disease staging, theranostics, monitoring, and as an outcome measure for interventional studies. Yet, there are significant challenges and hurdles to overcome before it can be implemented into widespread clinical practice. On November 17, 2022, the U.S. Food and Drug Administration, Society of Nuclear Medicine and Molecular Imaging, and Medical Imaging and Technology Alliance cosponsored a public workshop comprising experts from academia, industry, and government agencies to discuss the role of quantitative brain amyloid PET imaging in staging, prognosis, and longitudinal assessment of Alzheimer disease. The workshop discussed a range of topics, including available radiopharmaceuticals for amyloid imaging; the methodology, metrics, and analytic validity of quantitative amyloid PET imaging; its use in disease staging, prognosis, and monitoring of progression; and challenges facing the field. This report provides a high-level summary of the presentations and the discussion.


Assuntos
Amiloide , Encéfalo , Tomografia por Emissão de Pósitrons , Humanos , Tomografia por Emissão de Pósitrons/métodos , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Amiloide/metabolismo , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/metabolismo
2.
Biomark Med ; 17(11): 523-531, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37713233

RESUMO

The US FDA convened a virtual public workshop with the goals of obtaining feedback on the terminology needed for effective communication of multicomponent biomarkers and discussing the diverse use of biomarkers observed across the FDA and identifying common issues. The workshop included keynote and background presentations addressing the stated goals, followed by a series of case studies highlighting FDA-wide and external experience regarding the use of multicomponent biomarkers, which provided context for panel discussions focused on common themes, challenges and preferred terminology. The final panel discussion integrated the main concepts from the keynote, background presentations and case studies, laying a preliminary foundation to build consensus around the use and terminology of multicomponent biomarkers.

3.
J Neurotrauma ; 38(20): 2831-2840, 2021 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-34275326

RESUMO

The National Institutes of Health/National Institute of Neurological Disorders and Stroke (NIH-NINDS) Traumatic Brain Injury (TBI) Imaging Common Data Elements (CDEs) are standardized definitions for pathological intracranial lesions based on their appearance on neuroimaging studies. The NIH-NINDS TBI Imaging CDEs were designed to be as consistent as possible with the U.S. Food and Drug Administration (FDA) definition of biomarkers as "an indicator of normal biological processes, pathogenic processes, or biological responses to an exposure or intervention." However, the FDA qualification process for biomarkers requires proof of reliable biomarker test measurements. We determined the interrater reliability of TBI Imaging CDEs on subacute brain magnetic resonance imaging (MRI) performed on 517 mild TBI patients presenting to 11 U.S. level 1 trauma centers. Three U.S. board-certified neuroradiologists independently evaluated brain MRI performed 2 weeks post-injury for the following CDEs: traumatic axonal injury (TAI), diffuse axonal injury (DAI), and brain contusion. We found very high interrater agreement for brain contusion, with prevalence- and bias-adjusted kappa (PABAK) values for pairs of readers from 0.92 [95% confidence interval, 0.88-0.95] to 0.94 [0.90-0.96]. We found intermediate agreement for TAI and DAI, with PABAK values of 0.74-0.78 [0.70-0.82]. The near-perfect agreement for subacute brain contusion is likely attributable to the high conspicuity and distinctive appearance of these lesions on T1-weighted images. Interrater agreement for TAI and DAI was lower, because signal void in small vascular structures, and artifactual foci of signal void, can be difficult to distinguish from the punctate round or linear areas of slight hemorrhage that are a common hallmark of TAI/DAI on MRI.


Assuntos
Concussão Encefálica/diagnóstico por imagem , Lesões Encefálicas Traumáticas/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Adolescente , Adulto , Idoso , Artefatos , Biomarcadores , Contusão Encefálica/diagnóstico por imagem , Elementos de Dados Comuns , Lesão Axonal Difusa/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Estados Unidos , Adulto Jovem
4.
Med Phys ; 46(12): 5562-5571, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31419320

RESUMO

PURPOSE: To provide an overview of the types of adverse events reported to the US Food and Drug Administration (US FDA) for magnetic resonance (MR) systems over a 10-yr period. METHODS: Two reviewers independently reviewed adverse events reported to FDA for MR systems from 1 January 2008 to 31 December 2017 and manually categorized events into eight event types. Thermal events were further subcategorized by probable cause. Objects that became projectiles were also categorized. RESULTS: FDA received 1568 adverse event reports for MR systems between 1 January 2008 and 31 December 2017. This analysis included 1548 reports. Thermal events were the most commonly reported serious injury (59% of analyzed reports). Mechanical events - defined as slips, falls, crush injuries, broken bones, and cuts; musculoskeletal injuries from lifting or movement of the device - (11%), projectile events (9%), and acoustic events (6%) were also observed. CONCLUSIONS: Adverse events related to MR systems consistent with the known hazards of the MR environment continue to be reported to FDA. Increased awareness of the types of adverse events occurring for MR imaging systems is important for prevention.


Assuntos
Imageamento por Ressonância Magnética/efeitos adversos , Relatório de Pesquisa , United States Food and Drug Administration/estatística & dados numéricos , Humanos , Estados Unidos , United States Food and Drug Administration/legislação & jurisprudência
7.
Muscle Nerve ; 44(5): 805-13, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22006695

RESUMO

INTRODUCTION: Increased reliance on bulbospinal motor systems has been implicated in individuals with chronic stroke during maximum voluntary arm joint torque generation. METHODS: Maximum isometric single-joint and multi-joint arm strength was observed in two body orientations (sitting and supine) while maintaining identical head/neck/trunk/extremity joint configurations in order to identify bulbospinal contributions to maximum joint torque generation in 11 individuals with stroke and 10 individuals without stroke. RESULTS: During sitting, shoulder flexion was greater for both groups, whereas shoulder extension and elbow flexion, part of the "flexion synergy," were greater only in individuals with stroke. CONCLUSIONS: Body orientation influenced isometric arm strength, notably the constituents of flexion synergy in individuals with stroke, suggesting bulbospinal motor pathway involvement. From a practical perspective, clinical evaluation of single joint strength in the supine position may underestimate strength available during activities of daily living that are performed in an upright orientation.


Assuntos
Braço/fisiologia , Movimento/fisiologia , Orientação/fisiologia , Acidente Vascular Cerebral/fisiopatologia , Torque , Adulto , Idoso , Eletromiografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estimulação Luminosa/métodos , Desempenho Psicomotor/fisiologia , Amplitude de Movimento Articular/fisiologia , Adulto Jovem
8.
J Neurosci Methods ; 161(2): 314-22, 2007 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-17196255

RESUMO

Functional magnetic resonance imaging (fMRI) experiments investigating cortical activity while controlling task performance are difficult to conduct due to the high magnetic field environment and a lack of compatible measurement tools. We describe a method to measure the generation of isometric shoulder and elbow torques with a six-degrees-of-freedom (DOF) load cell during an event-related fMRI study. Feasibility of this method is demonstrated by finding cortical activity on the motor cortices in a participant during an event-related study of shoulder abduction and elbow flexion. The described methodology permits researchers to control and measure intersubject and intrasubject motor task performance during event-related brain imaging.


Assuntos
Encéfalo/fisiologia , Articulação do Cotovelo/fisiologia , Potenciais Evocados/fisiologia , Contração Isométrica/fisiologia , Imageamento por Ressonância Magnética/métodos , Miografia/instrumentação , Articulação do Ombro/fisiologia , Adulto , Artefatos , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Masculino , Manometria/instrumentação , Manometria/métodos , Músculo Esquelético/fisiologia , Miografia/métodos , Amplitude de Movimento Articular , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Transdutores
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