RESUMO
PURPOSE: To retrospectively evaluate the diagnostic performance of a 1-min contrast-enhanced 3D-FLASH pulse sequence for detecting intracranial enhancing lesions compared to standard contrast-enhanced 3D-MPRAGE pulse sequence. METHODS: Contrast-enhanced 3D-FLASH (acquisition time 49 s) and contrast-enhanced 3D-MPRAGE (4 min 35 s) pulse sequences were performed consecutively in 110 inpatient/emergency department 3T MRI brain examinations and analyzed by two independent neuroradiologist readers. For each sequence, the readers recorded (1) number of enhancing intracranial lesions; (2) intracranial susceptibility artifact (presence or absence; mm depth of intracranial signal loss); and (3) motion artifact (none, mild, moderate, severe). Inter and intra-reader agreement and reader accuracy relative to a reference standard were determined, and sequence comparison with respect to susceptibility and motion artifacts was performed. RESULTS: There was substantial intra-reader, inter-sequence agreement [reader 1, κ = 0.70 (95% CI: [0.60, 0.81]); reader 2, κ = 0.70 (95% CI: [0.59, 0.82])] and substantial intra-sequence, inter-reader agreement [3D-MPRAGE assessment, κ = 0.76 (95% CI: [0.66, 0.86]); 3D-FLASH assessment, κ = 0.86 (95% CI: [0.77, 0.94]) for detection of intracranial enhancing lesions. For both readers, the diagnostic accuracy of 3D-FLASH and 3D-MPRAGE was similar (3D-MPRAGE: 86.4 and 88.1%; 3D-FLASH: 88.2 and 84.5%), with no inter-sequence diagnostic accuracy discordancy between the sequences for either reader. 3D-FLASH was associated with less susceptibility artifact (p < 0.001 both readers) and less motion artifact (p < 0.001 both readers). CONCLUSION: On 3T brain MRI in the inpatient and emergency department setting, 1-min 3D-FLASH pulse sequence achieved comparable diagnostic performance to 4.5 min 3D-MPRAGE pulse sequence for detecting enhancing intracranial lesions, with reduced susceptibility and motion artifacts.
Assuntos
Pacientes Internados , Imageamento por Ressonância Magnética , Encéfalo/diagnóstico por imagem , Serviço Hospitalar de Emergência , Humanos , Estudos RetrospectivosAssuntos
Aorta/cirurgia , Aortografia/métodos , Perda Sanguínea Cirúrgica/prevenção & controle , Implante de Prótese Vascular/efeitos adversos , Angiografia por Tomografia Computadorizada , Fístula/diagnóstico por imagem , Técnicas Hemostáticas/efeitos adversos , Pericárdio/transplante , Adulto , Animais , Aorta/diagnóstico por imagem , Bovinos , Evolução Fatal , Fístula/etiologia , Xenoenxertos , Humanos , Masculino , Valor Preditivo dos Testes , Resultado do TratamentoRESUMO
Motor training can induce profound physiological plasticity within primary motor cortex, including changes in corticospinal output and motor map topography. Using transcranial magnetic stimulation, we show that training-dependent increases in the amplitude of motor-evoked potentials and motor map reorganization are reduced in healthy subjects with a val66met polymorphism in the brain-derived neurotrophic factor gene (BDNF), as compared to subjects without the polymorphism. The results suggest that BDNF is involved in mediating experience-dependent plasticity of human motor cortex.
Assuntos
Substituição de Aminoácidos/genética , Fator Neurotrófico Derivado do Encéfalo/genética , Córtex Motor/fisiologia , Destreza Motora/fisiologia , Plasticidade Neuronal/genética , Polimorfismo Genético/genética , Adulto , Mapeamento Encefálico , Potencial Evocado Motor/genética , Feminino , Genótipo , Humanos , Aprendizagem/fisiologia , Masculino , Metionina/genética , Córtex Motor/anatomia & histologia , Movimento/fisiologia , Regeneração Nervosa/genética , Testes Neuropsicológicos , Recuperação de Função Fisiológica/genética , Estimulação Magnética Transcraniana , Valina/genéticaRESUMO
RATIONALE: Ethanol and caffeine are two of the most widely consumed drugs in the world, often used in the same setting. Animal models may help to understand the conditions under which incidental memories formed just before ethanol intoxication might be lost or become difficult to retrieve. OBJECTIVES: Ethanol-induced retrograde amnesia was investigated using a new odor-recognition test. MATERIALS AND METHODS: Rats thoroughly explored a wood bead taken from the cage of another rat, and habituated to this novel odor (N1) over three trials. Immediately following habituation, rats received saline, 25 mg/kg pentylenetetrazol (a seizure-producing agent known to cause retrograde amnesia) to validate the test, 1.0 g/kg ethanol, or 3.0 g/kg ethanol. The next day, they were presented again with N1 and also a bead from a new rat's cage (N2). RESULTS: Rats receiving saline or the lower dose of ethanol showed overnight memory for N1, indicated by preferential exploration of N2 over N1. Rats receiving pentylenetetrazol or the higher dose of ethanol appeared not to remember N1, in that they showed equal exploration of N1 and N2. Caffeine (5 mg/kg), delivered either 1 h after the higher dose of ethanol or 20 min prior to habituation to N1, negated ethanol-induced impairment of memory for N1. A combination of a phosphodiesterase-5 inhibitor and an adenosine A(2A) antagonist, mimicking two major mechanisms of action of caffeine, likewise prevented the memory impairment, though either drug alone had no such effect. Binge alcohol can induce retrograde, caffeine-reversible disruption of social odor memory storage or recall.
Assuntos
Amnésia Retrógrada/induzido quimicamente , Amnésia Retrógrada/prevenção & controle , Cafeína/uso terapêutico , Depressores do Sistema Nervoso Central/toxicidade , Estimulantes do Sistema Nervoso Central/uso terapêutico , Etanol/toxicidade , Antagonistas do Receptor A2 de Adenosina , Animais , Cafeína/administração & dosagem , Cafeína/farmacologia , Estimulantes do Sistema Nervoso Central/administração & dosagem , Estimulantes do Sistema Nervoso Central/farmacologia , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Comportamento Exploratório/efeitos dos fármacos , Habituação Psicofisiológica , Injeções Intraperitoneais , Masculino , Odorantes , Pentilenotetrazol/toxicidade , Inibidores da Fosfodiesterase 5 , Purinonas/administração & dosagem , Ratos , Ratos Long-Evans , Ratos Sprague-Dawley , Reconhecimento Psicológico , Convulsões/induzido quimicamente , Olfato , Fatores de Tempo , Triazinas/administração & dosagem , Triazóis/administração & dosagem , MadeiraRESUMO
This study examined whether epidurally delivered cortical electrical stimulation (CS) improves the efficacy of motor rehabilitative training and alters neuronal density and/or cell proliferation in perilesion cortex following ischemic sensorimotor cortex (SMC) lesions. Adult rats were pre-trained on a skilled reaching task and then received partial unilateral SMC lesions and implantation of electrodes over the remaining SMC. Ten to fourteen days later, rats received daily reach training concurrent with anodal or cathodal 100 Hz CS or no stimulation (NoCS) for 18 days. To label newly generated cells, bromodeoxyuridine (BrdU; 50 mg/kg) was administered every third day of training. Both anodal and cathodal CS robustly enhanced reaching performance compared to NoCS controls. Neuronal density in the perilesion cortex was significantly increased in the cathodal CS group compared to the NoCS group. There were no significant group differences in BrdU-labeled cell density in ipsilesional cortex. Staining with Fluoro-Jade-B indicated that neurons continue to degenerate near the infarct at the time when cortical stimulation and rehabilitation were initiated. These data indicate that epidurally delivered CS greatly improves the efficacy of rehabilitative reach training following SMC damage and raise the possibility that cathodal CS may influence neuronal survival in perilesion cortex.