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PURPOSE: Changes in cerebral cortical regions occur in HIV-infected patients, even in those with mild neurocognitive disorders. Working memory / attention is one of the most affected cognitive domain in these patients, worsening their quality of life. Our objective was to assess whether cortical thickness differs between HIV-infected patients with and without working memory deficit. METHODS: Forty-one adult HIV-infected patients with and without working memory deficit were imaged on a 1.5 T scanner. Working memory deficit was classified by composite Z scores for performance on the Digits and Letter-Number Sequencing subtests of the Wechsler Adult Intelligence Scale (third edition; WAIS-III). Cortical thickness was determined using FreeSurfer software. Differences in mean cortical thickness between groups, corrected for multiple comparisons using Monte-Carlo simulation, were examined using the query design estimate contrast tool of the FreeSurfer software. RESULTS: Greater cortical thickness in left pars opercularis of the inferior frontal gyrus, and rostral and caudal portions of the left middle frontal gyrus (cluster 1; p = .004), and left superior frontal gyrus (cluster 2; p = .004) was observed in HIV-infected patients with working memory deficit compared with those without such deficit. Negative correlations were found between WAIS-III-based Z scores and cortical thickness in the two clusters (cluster 1: ρ = -0.59; cluster 2: ρ = -0.47). CONCLUSION: HIV-infected patients with working memory deficit have regions of greater thickness in the left frontal cortices compared with those without such deficit, which may reflect increased synaptic contacts and/or an inflammatory response related to the damage caused by HIV infection.
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Corteza Cerebral/patología , Corteza Cerebral/virología , Infecciones por VIH/patología , Trastornos de la Memoria/virología , Memoria a Corto Plazo/fisiología , Adulto , Anciano , Brasil/epidemiología , Femenino , VIH/aislamiento & purificación , Infecciones por VIH/epidemiología , Infecciones por VIH/psicología , Infecciones por VIH/virología , Humanos , Masculino , Trastornos de la Memoria/epidemiología , Trastornos de la Memoria/patología , Trastornos de la Memoria/psicología , Persona de Mediana Edad , Pruebas NeuropsicológicasRESUMEN
BACKGROUND: Soft tissue attenuation artifacts are the most common cause of misinterpretation in myocardial perfusion Imaging (MPI). Few studies assessing the value of prone imaging in women have been published. Breast attenuation artifacts can be present in up to 40% of the MPI studies in women. OBJECTIVES: This study aimed at evaluating the potential impact of prone MPI on breast attenuation, with a critical analysis of activity optimization and breast size influence. METHODS: MPI of an Anthropomorphic Torso Phantom with silicone breast prostheses and equivalent adipose tissue was compared to a standard MPI database. RESULTS: A medical qualitative and semiquantitative analysis demonstrated higher uptake in the LV anterior segments in the prone position for all injected activities. An artificial myocardium lesion was diagnosable in the right segment in all images, which shows that prone positioning would not mask a true lesion and it assists the cardiologist with a more accurate analysis. These results showed that it is possible to optimize the activity to be injected by up to 55.6% when using combined supine-prone images. CONCLUSION: Prone position has a high impact on the interpretation of MPI in female patients since it reduces the breast attenuation artifacts, and optimizes the radiation protection of the patient and all staff involved in the procedure, making it more cost-effective.
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Mama/diagnóstico por imagen , Imagen de Perfusión Miocárdica , Artefactos , Femenino , Humanos , Fantasmas de Imagen , Posición PronaRESUMEN
Objective The main goal of this study was to correlate migraine improvement, after prophylactic therapy, with cortical thickness changes. Methods Cortical thickness maps were obtained with magnetic resonance imaging (MRI) from 19 patients with migraine before (first scan) and after (second scan) prophylactic treatment, and these were compared with controls using the FreeSurfer MRI tool. Cortical changes were correlated with the headache index (HI). Results Anincrease incortical thickness was found in the right cuneus and precuneus, somatosensory and superior parietal cortices in both patient scans, compared with the controls. No changes were observed in the left hemisphere. Following correction for multiple comparisons, no areas changed from the first to the second scan. Regression analysis showed a significant negative correlation between the HI improvement and cortical thickness changes in the left posterior cingulate, a region involved with nociception and, possibly, the development of chronic pain. Conclusion There were changes in cortical thickness in patients with migraine relative to controls in areas involved with vision and pain processing. Left posterior cingulate cortical changes correlated with headache frequency and intensity.
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Giro del Cíngulo/patología , Trastornos Migrañosos/patología , Trastornos Migrañosos/prevención & control , Adulto , Estudios de Casos y Controles , Femenino , Giro del Cíngulo/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Trastornos Migrañosos/diagnóstico por imagen , Método de Montecarlo , Tamaño de los Órganos , Profilaxis Posexposición/métodos , Valores de Referencia , Reproducibilidad de los Resultados , Estudios Retrospectivos , Índice de Severidad de la Enfermedad , Estadísticas no Paramétricas , Resultado del Tratamiento , Adulto JovenRESUMEN
ABSTRACT Objective The main goal of this study was to correlate migraine improvement, after prophylactic therapy, with cortical thickness changes. Methods Cortical thickness maps were obtained with magnetic resonance imaging (MRI) from 19 patients with migraine before (first scan) and after (second scan) prophylactic treatment, and these were compared with controls using the FreeSurfer MRI tool. Cortical changes were correlated with the headache index (HI). Results Anincrease incortical thickness was found in the right cuneus and precuneus, somatosensory and superior parietal cortices in both patient scans, compared with the controls. No changes were observed in the left hemisphere. Following correction for multiple comparisons, no areas changed from the first to the second scan. Regression analysis showed a significant negative correlation between the HI improvement and cortical thickness changes in the left posterior cingulate, a region involved with nociception and, possibly, the development of chronic pain. Conclusion There were changes in cortical thickness in patients with migraine relative to controls in areas involved with vision and pain processing. Left posterior cingulate cortical changes correlated with headache frequency and intensity.
RESUMO Objetivos Correlacionar a melhora de pacientes enxaquecosos após tratamento preventivo com alterações na espessura do córtex cerebral. Métodos Espessura cortical foi determinada a partir de imagens de ressonância magnética (RM)em 19 pacientes com enxaqueca, antes (1ᵃ RM) e após (2ᵃ RM) o tratamento profilático, e comparada com controles, usando o programa FreeSurfer. Mudanças corticais foram correlacionadas com o índice de cefaleia (HI). Resultados O hemisfério direito apresentou aumento da espessura no córtex do cúneus e pré-cúneus, parietal superior e somatossensitivo na primeira RM e na segunda RM, em comparação aos controles. Após correção para comparações múltiplas, nenhuma região cortical se mostrou estatisticamente diferente entre a primeira e a segunda RM. A regressão mostrou correlação (negativa) significativa entre melhora do HI e mudanças na espessura cortical do cíngulo posterior esquerdo. Conclusão Existem alterações de espessura cortical em pacientes com enxaqueca em relação a controles em áreas envolvidas com processamento visual e com a dor. As alterações corticais no cíngulo posterior esquerdo variaram de acordo com a frequência e intensidade das crises.
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Humanos , Masculino , Femenino , Adulto , Adulto Joven , Giro del Cíngulo/patología , Trastornos Migrañosos/patología , Trastornos Migrañosos/prevención & control , Tamaño de los Órganos , Valores de Referencia , Índice de Severidad de la Enfermedad , Imagen por Resonancia Magnética/métodos , Estudios de Casos y Controles , Método de Montecarlo , Reproducibilidad de los Resultados , Estudios Retrospectivos , Resultado del Tratamiento , Estadísticas no Paramétricas , Profilaxis Posexposición/métodos , Giro del Cíngulo/diagnóstico por imagen , Trastornos Migrañosos/diagnóstico por imagenRESUMEN
PURPOSE: Currently, the diagnosis of attention deficit hyperactivity disorder (ADHD) rests on clinical criteria. Nonetheless, neuroimaging studies have demonstrated that children with ADHD have different cortical thickness and volume measures to typically developing children (TDC). In general, studies do not evaluate the influence of clinical presentation in the brain morphometry of ADHD children. Our objective was to perform a pilot study in order to evaluate cortical thickness and brain volume in a sample of Brazilian ADHD children and compare these to those of TDC, taking into account the influence of clinical presentation. METHODS: We performed an analytic study comparing 17 drug-naïve ADHD children of both genders, aged between 7 and 10, and 16 TDC. ADHD subjects were first considered as one group and further separated based on clinical presentation. RESULTS: The brain volume did not differ between patients and TDC. Smaller cortical thicknesses were identified on the left superior, medium and inferior temporal cortex, as well as in the left inferior parietal cortex. When compared to TDC, combined and inattentive ADHD presentations depicted smaller cortical thickness with high significance and power. The same magnitude of results was not observed when comparing inattentive ADHD and TDC. CONCLUSIONS: In this pilot study, ADHD is associated with abnormalities involving the cortical thickness of the posterior attentional system. The cortical thickness in the left superior, medium and inferior temporal cortex, as well as in the left inferior parietal cortex may differ according to ADHD presentations.
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Trastorno por Déficit de Atención con Hiperactividad/patología , Mapeo Encefálico , Corteza Cerebral/anomalías , Encéfalo , Niño , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Proyectos PilotoRESUMEN
OBJECTIVE: This study investigated differences in subcortical brain volumes of SLE patients with cognitive deficits (SLE-CD) and SLE patients with normal cognitive performance (SLE-CN), regardless of the presence of other neuropsychiatric symptoms. METHOD: We studied 40 patients divided into two-matched groups (SLE-CD n = 20; SLE-CN n = 20), with age ranging from 21 to 63 years old (100 % female) and 14.73 ± 10.18 years of diagnosis. Magnetic resonance imaging exams were performed on a 1.5 T scanner. A neuropsychological flexible battery was applied individually, including reasoning/problem-solving, praxis, episodic and working memory, processing speed, language/fluency, executive functions (inhibition and flexibility), and sustained attention. Z score ≤ - 2.0 in any dimension was considered as a cut-off for being considered to possess cognitive deficits. One-way analyses of covariance (ANCOVA) were performed to compare the brain structure volumes between groups. The analyses were controlled for the effects of lupus-related neuropsychiatric disorders. RESULTS: SLE patients with cognitive deficits had significantly smaller volumes in the left hippocampus, amygdala, and the right hippocampus than SLE patients without cognitive deficits. CONCLUSION: SLE patients with cognitive deficits appeared to have reduced temporal lobe structures when compared with SLE without cognitive deficits. These results corroborate a systems vulnerability model that investigated temporal lobe vulnerability during normal aging and in other neurological disorders.
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Encéfalo/patología , Disfunción Cognitiva/etiología , Disfunción Cognitiva/patología , Vasculitis por Lupus del Sistema Nervioso Central/complicaciones , Vasculitis por Lupus del Sistema Nervioso Central/patología , Imagen por Resonancia Magnética/métodos , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Tamaño de los Órganos , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
OBJECTIVE: To perform a pilot study to investigate the association between working memory and cortical thickness in a sample of attention deficit/hyperactivity disorder (ADHD) children. METHODS: Seventeen children aged 7-10 years diagnosed with ADHD and 16 healthy children underwent a magnetic resonance scan for cortical thickness measurements. Data was correlated with working memory performance using the Backwards Digit Span subtest of the Wechsler Intelligence Scale for Children. RESULTS: Working memory impairment, evidenced by lower scores on the Backwards Digit Span, was observed in patients with ADHD compared to healthy controls. There was a direct correlation between working memory and cortical thickness of the left medial temporal lobe (Spearman's correlation coefficient: 0.499; p < 0.005). CONCLUSIONS: Our data suggests, for the first time, a correlation between working memory, evaluated by the Backwards Digit Span, and left medial temporal cortical thickness.
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Trastorno por Déficit de Atención con Hiperactividad/fisiopatología , Memoria a Corto Plazo/fisiología , Lóbulo Temporal/anatomía & histología , Lóbulo Temporal/fisiopatología , Factores de Edad , Estudios de Casos y Controles , Niño , Femenino , Humanos , Imagen por Resonancia Magnética , Masculino , Pruebas Neuropsicológicas , Proyectos Piloto , Valores de Referencia , Factores Sexuales , Estadísticas no Paramétricas , Encuestas y Cuestionarios , Lóbulo Temporal/diagnóstico por imagen , Escalas de WechslerRESUMEN
ABSTRACT Objective To perform a pilot study to investigate the association between working memory and cortical thickness in a sample of attention deficit/hyperactivity disorder (ADHD) children. Methods Seventeen children aged 7-10 years diagnosed with ADHD and 16 healthy children underwent a magnetic resonance scan for cortical thickness measurements. Data was correlated with working memory performance using the Backwards Digit Span subtest of the Wechsler Intelligence Scale for Children. Results Working memory impairment, evidenced by lower scores on the Backwards Digit Span, was observed in patients with ADHD compared to healthy controls. There was a direct correlation between working memory and cortical thickness of the left medial temporal lobe (Spearman’s correlation coefficient: 0.499; p < 0.005). Conclusions Our data suggests, for the first time, a correlation between working memory, evaluated by the Backwards Digit Span, and left medial temporal cortical thickness.
RESUMO Objetivo Realizar estudo piloto para investigar a associação entre memória de trabalho e espessura cortical em crianças com transtorno de défict de atenção e hiperatividade (TDAH). Métodos Dezessete crianças com TDAH, entre 7 e 10 anos, e dezesseis crianças saudáveis foram submetidas a ressonância magnética para aferição de espessura cortical. Os dados foram correlacionados com desempenho da memória de trabalho usando a ordem inversa do subteste Dígitos da Escala de Inteligência Wechsler para Crianças. Resultados Prejuízos na memória de trabalho, evidenciado pela menor pontuação na ordem inversa do subteste Dígitos, foram observados em pacientes com TDAH, em comparação com crianças saudáveis. Observou-se correlação direta entre memória de trabalho e espessura do lobo temporal médio à esquerda (coeficiente de correlação de Spearman: 0,499; p < 0,005). Conclusões Nossos dados sugerem, pela primeira vez, uma correlação entre memória de trabalho, avaliada através da pontuação na ordem inversa do subteste Dígitos, e espessura do córtex temporal medial à esquerda.
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Humanos , Masculino , Femenino , Niño , Trastorno por Déficit de Atención con Hiperactividad/fisiopatología , Lóbulo Temporal/anatomía & histología , Lóbulo Temporal/fisiopatología , Memoria a Corto Plazo/fisiología , Valores de Referencia , Lóbulo Temporal/diagnóstico por imagen , Escalas de Wechsler , Imagen por Resonancia Magnética , Estudios de Casos y Controles , Proyectos Piloto , Factores Sexuales , Encuestas y Cuestionarios , Factores de Edad , Estadísticas no Paramétricas , Pruebas NeuropsicológicasRESUMEN
Esse artigo trata das Diretrizes da Cintilografia Miocárdica de Repouso e Esforço. Foi desenvolvido e escrito pela Sociedade Brasileira de Medicina Nuclear para que sirva como guia das melhores práticas usadas em Medicina Nuclear. Sua função é ser uma ferramenta educacional para ajudar os serviços de Medicina Nuclear do Brasil a garantirem um atendimento de qualidade aos pacientes
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Humanos , Pacientes , Cintigrafía/métodos , Guías como Asunto/normas , Imagen de Perfusión Miocárdica/métodos , Calidad de Vida , Diagnóstico por Imagen/métodos , Guía de Práctica Clínica , Prueba de Esfuerzo/métodosRESUMEN
Episodic memory deficits in systemic lupus erythematosus (SLE) have been frequently reported in the literature; however, little is known about the neural correlates of these deficits. We investigated differences in the volumes of different brain structures of SLE patients with and without episodic memory impairments diagnosed by the Rey Auditory Verbal Learning Test (RAVLT). Groups were paired based on age, education, sex, Mini Mental State Examination score, accumulation of disease burden (SLICC), and focused attention dimension score. Patients underwent magnetic resonance imaging (MRI). Cortical volumetric reconstruction and segmentation of the MR images were performed with the FreeSurfer software program. SLE patients with episodic memory deficits presented shorter time of diagnosis than SLE patients without episodic memory deficits. ANOVA revealed that SLE patients with episodic memory deficits had a larger third ventricle volume than SLE patients without episodic memory deficits and controls. Additionally, covariance analysis indicated group effects on the bilateral thalamus and on the third ventricle. Our findings indicate that episodic memory may be impaired in SLE patients with normal hippocampal volume. In addition, the thalamus may undergo volumetric changes associated with episodic memory loss in SLE.
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Lupus Eritematoso Sistémico/complicaciones , Trastornos de la Memoria/complicaciones , Memoria Episódica , Tálamo/patología , Tercer Ventrículo/patología , Adulto , Femenino , Humanos , Lupus Eritematoso Sistémico/patología , Lupus Eritematoso Sistémico/psicología , Imagen por Resonancia Magnética , Masculino , Trastornos de la Memoria/patología , Trastornos de la Memoria/psicología , Persona de Mediana Edad , Pruebas Neuropsicológicas , Tamaño de los Órganos , Adulto JovenRESUMEN
Duodenal contractions are thought to play a role in the control of gastric emptying. Although noninvasive techniques, such as ultrasonography and MRI, have been proposed for studying duodenal contractile activity in humans, there are no reports on the use of scintigraphy for this purpose. This work aimed to describe a novel scintigraphic technique for assessing duodenal contractility during gastric emptying in humans, and to present preliminary data on the frequency and amplitude of contractions detected in three different duodenal segments. Fasted young healthy volunteers (N=12) were given either a liquid or a solid test meal of similar calorie content (400 kcal) labeled with 99mTc-phytate. Static images were collected to determine gastric emptying. Dynamic images of the anterior aspect of the abdomen (1 frame/s) were also acquired periodically in a standard position for 256 s at 15-30 min intervals. 'Activity versus time' curves were generated for regions of interest corresponding to the proximal, middle, and distal duodenal segments. Curves were digitally filtered and processed to estimate both dominant frequency (fast Fourier transform) and amplitude (mean ejection fraction) of postprandial duodenal contractions. There were no significant differences regarding dominant frequency among proximal, middle, and distal duodenal regions of interest. In addition, there were no significant differences between the liquid and the solid meal in terms of either frequency or amplitude of duodenal contractions. Characterization of duodenal contractions in humans using scintigraphy is feasible and yields consistent data for both the frequency and the amplitude of postprandial contractions, which seems to be rather independent of meal consistency.
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Duodeno/fisiología , Vaciamiento Gástrico , Contracción Muscular , Cintigrafía/métodos , Ayuno , Estudios de Factibilidad , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
Objetivo: Realizar um estudo de otimização de exames de cintilografia de perfusão miocárdica. Materiais e Métodos: Foram adquiridas imagens de um objeto simulador antropomórfico de tórax contendo coração, pulmões, fígado e coluna vertebral, em uma gama câmara SPECT GE modelo Ventri, utilizando-se diferentes atividades e variando-se os tempos de aquisição, de forma a verificar a influência destes parâmetros na qualidade da imagem clínica reconstruída. Foi utilizado o radiofármaco 99mTc-sestamibi e os testes realizados foram avaliados clinicamente a partir de notas, tanto para o summed stress score quanto para a qualidade técnica da imagem e perfusão. As quantificações foram realizadas pelo software ImageJ. Resultados: Os resultados demonstraram que, para o tempo padrão utilizado na realização dos exames de 15 segundos por ângulo, a atividade injetada poderia ser reduzida em 33,34%. Além disso, se o tempo usual de exame for reduzido em 54,34% (7 segundos por ângulo), ainda assim a atividade padrão injetada poderia ser reduzida em 16,67%, sem prejudicar a qualidade da imagem e a confiabilidade do diagnóstico. Conclusão: O método desenvolvido e os resultados obtidos podem ser utilizados para o desenvolvimento de um estudo clínico de pacientes em um protocolo otimizado. .
Objective: To develop a study aiming at optimizing myocardial perfusion imaging. Materials and Methods: Imaging of an anthropomorphic thorax phantom with a GE SPECT Ventri gamma camera, with varied activities and acquisition times, in order to evaluate the influence of these parameters on the quality of the reconstructed medical images. The 99mTc-sestamibi radiotracer was utilized, and then the images were clinically evaluated on the basis of data such as summed stress score, and on the technical image quality and perfusion. The software ImageJ was utilized in the data quantification. Results: The results demonstrated that for the standard acquisition time utilized in the procedure (15 seconds per angle), the injected activity could be reduced by 33.34%. Additionally, even if the standard scan time is reduced by 53.34% (7 seconds per angle), the standard injected activity could still be reduced by 16.67%, without impairing the image quality and the diagnostic reliability. Conclusion: The described method and respective results provide a basis for the development of a clinical trial of patients in an optimized protocol. .
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BACKGROUND: Chronic pain disorders are presumed to induce changes in brain grey and white matters. Few studies have focused CNS alterations in trigeminal neuralgia (TN). METHODS: The aim of this study was to explore changes in white matter microstructure in TN subjects using diffusion tensor images (DTI) with tract-based spatial statistics (TBSS); and cortical thickness changes with surface based morphometry. Twenty-four patients with classical TN (37-67 y-o) and 24 healthy controls, matched for age and sex, were included in the study. RESULTS: Comparing patients with controls, no diffusivity abnormalities of brain white matter were detected. However, a significant reduction in cortical thickness was observed at the left cuneus and left fusiform cortex in the patients group. The thickness of the fusiform cortex correlated negatively with the carbamazepine dose (p = 0.023). CONCLUSIONS: Since the cuneus and the fusiform gyrus have been related to the multisensory integration area and cognitive processing, as well as the retrieval of shock perception conveyed by Aδ fibers, our results support the role of these areas in TN pathogenesis. Whether such changes occurs as an epiphenomenon secondary to daily stimulation or represent a structural predisposition to TN in the light of peripheral vascular compression is a matter of future studies.
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Imagen de Difusión Tensora/métodos , Lóbulo Occipital/patología , Lóbulo Temporal/patología , Neuralgia del Trigémino/patología , Adulto , Corteza Cerebral/patología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Percepción del Dolor/fisiología , Neuralgia del Trigémino/fisiopatologíaRESUMEN
BACKGROUND: Alcoholic subjects manifest important deficits in frontal executive function, yet maintain cognitive mental status within normal range. METHODS: This study searched for volumetric measurements of segmented brain structures obtained from magnetic resonance imaging (MRI) that would predict executive functions and cognitive mental status in alcoholic subjects. The frontal assessment battery (FAB) and the Mini-Mental State Examination (MMSE) were applied to alcoholic subjects who underwent MRI. Cortical and subcortical segmentation and corrections were performed using FreeSurfer. Multiple linear regressions analyses having volumetric measures of segmented brain structures as predictors for FAB or MMSE scores as dependent measures were conducted. Sixty alcoholic subjects, 52 males, mean age of 47.2 ± SD 10.4 years, with heavy use of alcohol (mean 284.4 ± SD 275.9 g of alcohol/d) over a long time (mean 32.4 ± SD 11.1 years), showed FAB 11.1 ± SD 3.2 and MMSE of 25.2 ± SD 4.1. RESULTS: Multiple regression analyses having left and right side of each segment as predictors showed that gray matter volumes of rostral middle frontal cortex and cerebellar cortex (p < 0.001), in which only the left side of these structures showed significant partial effects in the full model (p < 0.05), showed to predict FAB performance. They were even more predictive when considered together (p < 0.001), in which both left rostral middle frontal cortex (p < 0.05) and left cerebellar cortex (p < 0.01) predictors had significant partial effects in the full model. None of brain structures was predictive of MMSE performance. CONCLUSIONS: We have concluded that volumetric measurements of left rostral middle frontal and cerebellar cortices seem to be able to predict the frontal executive performance but not the cognitive mental status in alcoholic subjects.
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Alcoholismo/diagnóstico , Corteza Cerebelosa/patología , Función Ejecutiva/fisiología , Lóbulo Frontal/patología , Sustancia Gris/patología , Adulto , Anciano , Alcoholismo/psicología , Escalas de Valoración Psiquiátrica Breve , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Tamaño de los Órganos , Valor Predictivo de las Pruebas , Adulto JovenRESUMEN
OBJECTIVE: To develop a study aiming at optimizing myocardial perfusion imaging. MATERIALS AND METHODS: Imaging of an anthropomorphic thorax phantom with a GE SPECT Ventri gamma camera, with varied activities and acquisition times, in order to evaluate the influence of these parameters on the quality of the reconstructed medical images. The (99m)Tc-sestamibi radiotracer was utilized, and then the images were clinically evaluated on the basis of data such as summed stress score, and on the technical image quality and perfusion. The software ImageJ was utilized in the data quantification. RESULTS: The results demonstrated that for the standard acquisition time utilized in the procedure (15 seconds per angle), the injected activity could be reduced by 33.34%. Additionally, even if the standard scan time is reduced by 53.34% (7 seconds per angle), the standard injected activity could still be reduced by 16.67%, without impairing the image quality and the diagnostic reliability. CONCLUSION: The described method and respective results provide a basis for the development of a clinical trial of patients in an optimized protocol.
OBJETIVO: Realizar um estudo de otimização de exames de cintilografia de perfusão miocárdica. MATERIAIS E MÉTODOS: Foram adquiridas imagens de um objeto simulador antropomórfico de tórax contendo coração, pulmões, fígado e coluna vertebral, em uma gama câmara SPECT GE modelo Ventri, utilizando-se diferentes atividades e variando-se os tempos de aquisição, de forma a verificar a influência destes parâmetros na qualidade da imagem clínica reconstruída. Foi utilizado o radiofármaco 99mTc-sestamibi e os testes realizados foram avaliados clinicamente a partir de notas, tanto para o summed stress score quanto para a qualidade técnica da imagem e perfusão. As quantificações foram realizadas pelo software ImageJ. RESULTADOS: Os resultados demonstraram que, para o tempo padrão utilizado na realização dos exames de 15 segundos por ângulo, a atividade injetada poderia ser reduzida em 33,34%. Além disso, se o tempo usual de exame for reduzido em 54,34% (7 segundos por ângulo), ainda assim a atividade padrão injetada poderia ser reduzida em 16,67%, sem prejudicar a qualidade da imagem e a confiabilidade do diagnóstico. CONCLUSÃO: O método desenvolvido e os resultados obtidos podem ser utilizados para o desenvolvimento de um estudo clínico de pacientes em um protocolo otimizado.
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BACKGROUND: Patients with Sickle cell disease (SCD) who receive regular transfusions are at risk for developing cardiac toxicity from iron overload. The aim of this study was to assess right and left cardiac volumes and function, late gadolinium enhancement (LGE) and iron deposits in patients with SCD using CMR, correlating these values with transfusion burden, ferritin and hemoglobin levels. METHODS: Thirty patients with SCD older than 20 years of age were studied in a 1.5 T scanner and compared to age- and sex-matched normal controls. Patients underwent analysis of biventricular volumes and function, LGE and T2* assessment of the liver and heart. RESULTS: When compared to controls, patients with SCD presented higher left ventricular (LV) volumes with decreased ejection fraction (EF) with an increase in stroke volume (SV) and LV hypertrophy. The right ventricle (RV) also presented with a decreased EF and hypertrophy, with an increased end-systolic volume. Although twenty-six patients had increased liver iron concentrations (median liver iron concentration value was 11.83 ± 9.66 mg/g), only one patient demonstrated an abnormal heart T2* < 20 msec. Only four patients (13%) LGE, with only one patient with an ischemic pattern. CONCLUSIONS: Abnormal heart iron levels and myocardial scars are not a common finding in SCD despite increased liver iron overload. The significantly different ventricular function seen in SCD compared to normal suggests the changes in RV and LV function may not be due to the anemia alone. Future studies are necessary to confirm this association.
Asunto(s)
Anemia de Células Falciformes/complicaciones , Hipertrofia Ventricular Izquierda/diagnóstico , Hipertrofia Ventricular Derecha/diagnóstico , Hígado/metabolismo , Imagen por Resonancia Magnética , Miocardio/patología , Disfunción Ventricular Izquierda/diagnóstico , Disfunción Ventricular Derecha/diagnóstico , Función Ventricular Izquierda , Función Ventricular Derecha , Adulto , Anemia de Células Falciformes/sangre , Estudios de Casos y Controles , Femenino , Ferritinas/sangre , Hemoglobinas/metabolismo , Humanos , Hipertrofia Ventricular Izquierda/sangre , Hipertrofia Ventricular Izquierda/etiología , Hipertrofia Ventricular Izquierda/fisiopatología , Hipertrofia Ventricular Derecha/sangre , Hipertrofia Ventricular Derecha/etiología , Hipertrofia Ventricular Derecha/fisiopatología , Masculino , Persona de Mediana Edad , Miocardio/metabolismo , Valor Predictivo de las Pruebas , Estudios Prospectivos , Volumen Sistólico , Disfunción Ventricular Izquierda/sangre , Disfunción Ventricular Izquierda/etiología , Disfunción Ventricular Izquierda/fisiopatología , Disfunción Ventricular Derecha/sangre , Disfunción Ventricular Derecha/etiología , Disfunción Ventricular Derecha/fisiopatología , Adulto JovenRESUMEN
PURPOSE: To evaluate the white matter integrity of the corona radiata, cingulate gyri, and corpus callosum in patients with human immunodeficiency virus (HIV) infection through diffusion tensor imaging (DTI). MATERIALS AND METHODS: Thirty-four patients with at least 5 years of HIV infection and 27 healthy controls underwent magnetic resonance imaging (MRI) in a 1.5 T scanner. A voxelwise-based technique was used to analyze the DTI data. RESULTS: We found that in the body of corpus callosum the fractional anisotropy (FA) was significantly reduced, whereas mean diffusivity (MD) and radial diffusivity (RD) were increased in HIV patients. Analyzing the corona radiata, axial diffusivity (AD) and MD were significantly increased in the left superior region, MD and RD were increased in the left posterior area, and, furthermore, MD was also increased in the right posterior region. No significant abnormalities were found on the cingulate gyri. The white matter damage, related to FA reduction, was associated with increased RD, indicating that demyelization might be the pathophysiological result of this damage. CONCLUSION: Since the DTI can detect abnormalities in the normal-appearing white matter, this technique may play a role as an early marker of HIV disease progression, including clinical manifestations such as cognitive impairment.
Asunto(s)
Cuerpo Calloso/patología , Imagen de Difusión Tensora/métodos , Giro del Cíngulo/patología , Infecciones por VIH/patología , Imagenología Tridimensional/métodos , Cápsula Interna/patología , Fibras Nerviosas Mielínicas/patología , Adulto , Anciano , Femenino , Humanos , Interpretación de Imagen Asistida por Computador/métodos , Masculino , Persona de Mediana Edad , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Brain abnormalities in neuromyelitis optica (NMO) have been reported previously, but the pathophysiological mechanism and clinical relevance of these abnormalities are poorly understood. We assessed the prevalence and patterns of brain MRI abnormalities in a Brazilian cohort of patients with NMO. Conventional brain MRI and medical records from 24 Brazilian patients with NMO were retrospectively evaluated. Brain MRI were classified into four subgroups: normal, non-specific lesions, multiple sclerosis (MS)-like lesions, and typical lesions. Brain lesions were detected in 19 patients (79.2%). Fourteen patients (58.3%) had non-specific lesions, three (12.5%) had MS-like lesions, and two (8.3%) had typical lesions. Differences between these subgroups with respect to the Expanded Disability Status Scale (EDSS) scores (p=0.86) were not significant. This study demonstrates a high prevalence of brain abnormalities in Brazilian patients with NMO; however, we did not find a significant relationship between these abnormalities and EDSS scores.