RESUMO
Attention deficit/hyperactivity disorder (ADHD) is one of the most frequent behavioral problems in school-age children. Although the etiology remains unclear, the involvement of the dopaminergic system has been suggested by genetic studies that report an overexpression of the dopamine transporter (DAT) gene. In spite of these abnormalities being directly related to the decrease of dopamine (DA) in the striatum (STR), abnormalities in brain perfusion have also been observed in cortical-subcortical structures. Functional neuroimaging studies have suggested that the DA concentration may cause changes in the cerebral blood flow (CBF). The objective of our study was to evaluate the relationship between DAT density in STR and cortical-subcortical impairment in CBF. Based on the hypothesis that there is a correlation between DA availability and brain perfusion, we postulated that individuals with ADHD, with a higher DAT density in the basal ganglia, will have lower perfusion in the fronto-striatal-cerebellar networks. We used Tc-99m TRODAT-1 SPECT to measure DAT density and Tc-99m ECD SPECT to assess brain perfusion. Ten adolescents diagnosed with ADHD by Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria were investigated. Analysis with Statistical Parametric Mapping 5 corrected for multiple comparisons, using small volume correction, showed a significant negative correlation between the DAT density in the STR and CBF in the cingulate gyrus, frontal lobe, temporal lobe, and cerebellum (pFDR <0.01). Our findings suggest that higher DAT density in the STR was associated with a decrease in the regional CBF in the cortical and subcortical attention network.
Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/metabolismo , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Circulação Cerebrovascular , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Adolescente , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico por imagem , Gânglios da Base/irrigação sanguínea , Gânglios da Base/diagnóstico por imagem , Gânglios da Base/metabolismo , Cisteína/análogos & derivados , Dopamina/metabolismo , Humanos , Masculino , Neostriado/irrigação sanguínea , Neostriado/diagnóstico por imagem , Neostriado/metabolismo , Compostos de Organotecnécio , Tomografia Computadorizada de Emissão de Fóton Único , Tropanos , Adulto JovemRESUMO
OBJECTIVE: To describe the reproducibility of the sentinel lymph node technique in patients with prostate cancer and verify if there is improved accuracy over modified lymphadenectomy. MATERIAL AND METHODS: Twenty-three patients with biopsy proven prostate cancer were enrolled in this study. Lymphoscintigraphy was performed after the transrectal administration of Tc sulfur colloid guided by ultrasound, with one injection in each prostate lobe. Images were obtained 15 and 180 min after injection. Sentinel lymph node was harvested during surgery using a gamma probe, followed by extended lymphadenectomy. RESULTS: The mean age of the patients in this study was 66 years. An average of 3.36 sentinel lymph nodes was found for each patient. Radioactive lymph nodes were identified by the gamma probe in 21 out of 23 patients. In one of the patients there was no radiopharmaceutical migration from the injection site and in another the sentinel lymph node was visualized by lymphoscintigraphy but was not found during surgery. Three patients had lymph node metastasis; in one of these patients the sentinel lymph node was the only positive node and was found outside the modified lymphadenectomy region (obturator fossa and the external iliac). CONCLUSION: Sentinel lymph node biopsy in prostate cancer adds important information to the staging of patients, not always attained through the lymphadenectomy restricted to the obturator fossa and external iliac. Such information is essential for the choice of the best treatment to be applied.