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Positron emission tomography with (18)F-fluorodeoxyglucose (FDG-PET) is considered the gold standard for myocardial viability. A pilot study was undertaken to compare FDG-PET using euglycemic hyperinsulinemic clamp before (18)F-fluorodeoxyglucose ((18)F-FDG) administration (PET-CLAMP) with a new proposed technique consisting of a 24-h low-carbohydrate diet before (18)F-FDG injection (PET-DIET), for the assessment of hypoperfused but viable myocardium (hibernating myocardium). Thirty patients with previous myocardial infarction were subjected to rest (99m)Tc-sestamibi-SPECT and two (18)F-FDG studies (PET-CLAMP and PET-DIET). Myocardial tracer uptake was visually scored using a 5-point scale in a 17-segment model. Hibernating myocardium was defined as normal or mildly reduced metabolism ((18)F-FDG uptake) in areas with reduced perfusion ((99m)Tc-sestamibi uptake) since (18)F-FDG uptake was higher than the degree of hypoperfusion-perfusion/metabolism mismatch indicating a larger flow defect. PET-DIET identified 79 segments and PET-CLAMP 71 as hibernating myocardium. Both methods agreed in 61 segments (agreement = 94.5 %, κ = 0.78). PET-DIET identified 230 segments and PET-CLAMP 238 as nonviable. None of the patients had hypoglycemia after DIET, while 20 % had it during CLAMP. PET-DIET compared with PET-CLAMP had a good correlation for the assessment of hibernating myocardium. To our knowledge, these data provide the first evidence of the possibility of myocardial viability assessment with this technique.
Assuntos
Dieta com Restrição de Carboidratos , Fluordesoxiglucose F18 , Técnica Clamp de Glucose , Imagem de Perfusão do Miocárdio/métodos , Miocárdio Atordoado/diagnóstico por imagem , Miocárdio/patologia , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Adulto , Idoso , Circulação Coronária , Estudos de Viabilidade , Feminino , Fluordesoxiglucose F18/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Miocárdio Atordoado/metabolismo , Miocárdio Atordoado/fisiopatologia , Miocárdio/metabolismo , Projetos Piloto , Valor Preditivo dos Testes , Compostos Radiofarmacêuticos/metabolismo , Tecnécio Tc 99m Sestamibi , Sobrevivência de Tecidos , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
Background. Chronic autoimmune thyroiditis (CAT) frequently alters thyroid vascularization, likely as a result of the autoimmune process. Objective. To evaluate the effects of low-level laser therapy (LLLT) on the thyroid vascularization of patients with hypothyroidism induced by CAT using color Doppler ultrasound parameters. Methods. In this randomized clinical trial, 43 patients who underwent levothyroxine replacement for CAT-induced hypothyroidism were randomly assigned to receive either 10 sessions of LLLT (L group, n = 23) or 10 sessions of a placebo treatment (P group, n = 20). Color Doppler ultrasounds were performed before and 30 days after interventions. To verify the vascularity of the thyroid parenchyma, power Doppler was performed. The systolic peak velocity (SPV) and resistance index (RI) in the superior (STA) and inferior thyroid arteries (ITAs) were measured by pulsed Doppler. Results. The frequency of normal vascularization of the thyroid lobes observed in the postintervention power Doppler examination was significantly higher in the L than in the P group (P = 0.023). The pulsed Doppler examination revealed an increase in the SPV of the ITA in the L group compared with the P group (P = 0.016). No significant differences in the SPV of the STA and in the RI were found between the groups. Conclusion. These results suggest that LLLT can ameliorate thyroid parenchyma vascularization and increase the SPV of the ITA of patients with hypothyroidism caused by CAT.
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INTRODUCTION: The accurate and reproducible assessment of cardiac volumes, function, and mass is of paramount importance in cardiology. In the present study we sought to determine whether the 3D cine-magnetic resonance (MR) technique, using the variable asymmetric sampling in time (VAST) approach, provided an accurate assessment of LV functional parameters when compared with the conventional 2D cine-MR technique. METHODS: A total of 43 consecutive patients referred for a CMR examination for clinical reasons and 14 healthy volunteers were included in the study. Cine images were acquired using a steady-state free precession pulse sequence. Two different multiphase acquisitions were performed: conventional 2D cine-MR and 3D cine-MR. The short-axis cine images acquired by both cine-MR techniques were used for the quantitative assessment of LV end-diastolic, end-systolic and stroke volumes, LV mass and ejection fraction. RESULTS: All CMR examinations were completed successfully, with both cine-MR imaging techniques yielding interpretable diagnostic results in all patients. Regarding the quantitative assessment, Bland-Altman analyses demonstrated a good agreement between the measurements of both cine-MR techniques for all LV parameters. In addition, the agreement between 2D and 3D cine-MR techniques for the qualitative assessment of LV global function was perfect (kappa = 1.0, P<0.001) for the two observers in consensus. The assessment performed by the third independent observer also demonstrated very good agreement (kappa = 0.88, P<0.001). CONCLUSION: The single breathhold 3D cine-MR technique provides an accurate and reproducible quantitative assessment of LV volumes, mass and function when compared with the conventional 2D cine-MR method.
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A total of 26 children (26 affected, 25 control hips) with Legg-Calvé-Perthes' disease (LCP) met the cooperation requirements for inclusion in the study using contrast-enhanced power Doppler sonography for assessment of changes in the revascularization flow. Sagittal sonograms were obtained before and at the peak effect of an intravenously injected microbubble-based contrast agent. Overall mean peak enhancement ratios were greater for children with later onset of disease (>5.8 years old) than for those with earlier onset (< or = 5.8) (p = 0.02). The use of ultrasound (US) contrast agents improved depiction of proximal femoral vascularity in all regions of the femoral head: epiphysis (n = 3, pre; n = 8, postcontrast), physis (n = 12, pre; n = 21, postcontrast) and metaphysis (n = 6, pre; n = 8, postcontrast) and resulted in a marked increase in the number of mean pixel intensity values within the physis (p = 0.02). In conclusion, contrast-enhanced power Doppler sonography is an effective method for demonstration of changes from the revascularization process in LCP, particularly within the physis.
Assuntos
Cabeça do Fêmur/irrigação sanguínea , Cabeça do Fêmur/diagnóstico por imagem , Doença de Legg-Calve-Perthes/diagnóstico por imagem , Ultrassonografia Doppler/métodos , Criança , Pré-Escolar , Meios de Contraste , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Microesferas , Variações Dependentes do ObservadorRESUMO
Os autores pretendem, neste estudo transversal ("cross-sectional") de pacientes co artrite reumatóide juvenil, comparar a análise bidimensional de espessura sinovial máxima obtida de cortes de sequencia axial sinovial (tridimensional) obtida de cortes da sequencia axial T1 SPIR ("spectral presaturation with inversion recovery") SE pós-gadolino. Estas duas formas de avaliaçäo imagenológica säo associadas a parâmetros clínicos, laboratoriais e á presença de realce sinovial á ressonância magnética, com objetivo de avaliaçäo de seu custo-benefício.