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Advisor(s)
Abstract(s)
O renograma com 99mTc-MAG3 permite a avaliação funcional do sistema urinário em utentes adultos e pediátricos. O protocolo para a realização do renograma tem vindo a padronizar-se, de acordo com recomendações internacionais. As guidelines mais recentes recomendam que, nos renogramas, a avaliação seja efetuada através de dois indicadores: a função renal relativa (FRR) e a excreção renal do traçador. Assim, surgiu a Atividade Residual Normalizada (NORA – Normalized Residual Activity), que é indicada para a avaliação de drenagem, e representa a quantidade de atividade que permanece no rim num dado instante comparativamente com a presente no segundo minuto do estudo. Pode ser calculada no final do estudo dinâmico (NORA20), em imagens adquiridas após a micção, precocemente após o estudo dinâmico (NORAPMi) e mais tardiamente (NORAPMt).
O objetivo desta dissertação visou estabelecer valores de referência da NORA por grupo etário, tipo de rim (normais, dilatados e obstruídos) e diferentes momentos de cálculo. Também se pretendeu estudar a influência da visualização da vesícula biliar no cálculo deste parâmetro, e avaliar as diferenças entre NORAPMi e NORAPMt bem como o seu impacto no diagnóstico de obstrução.
Para a concretização destes objetivos, realizaram-se renogramas com 99mTc-MAG3 em utentes com justificação clínica para o exame, e calculou-se, através de um software desenvolvido para o processamento de renogramas, os valores de NORA20, NORAPMi e NORAPMt.
O estudo desenvolvido permitiu obter valores de referência para utentes pediátricos e adultos. Sugere ainda que a visualização da vesícula biliar não interfere no cálculo da NORA. A NORAPMi e NORAPMt diferem entre si, exceto em rins obstruídos. Porém, a distinção entre rins dilatados e obstruídos através da análise da drenagem, apenas é possível através da NORAPMt, o que acentua a importância de aquisição de imagem de pós-micção entre os 50 e 60 minutos após o início do estudo dinâmico.
The 99mTc-MAG3 renogram allows functional evaluation of the urinary system in paediatric and adult patients. The protocol for performing this exam must be standardized, according to international recommendations. The most recent guidelines advise that the evaluation be performed through two indicators: relative renal function (RRF) and renal tracer excretion. Thus, Normalized Residual Activity (NORA) has emerged, it is the one indicated to evaluate drainage, and represents the renal counts that are still remaining in the kidney at any moment, divided by the renal counts present in the second minute of the study. It can be calculated at the end of the dynamic study (NORA20) and at postmicturition images, obtained early after the dynamic study (NORAPMi) and later (NORAPMt). The purpose of this project was to determine NORA reference values by age group, kidney condition (normal, dilated and obstructed) and different moments of calculation. It was also intended to study the influence of gallbladder on parameter calculation, and evaluate the differences between NORAPMi and NORAPMt and their impact on obstruction diagnosis. To achieve these objectives, 99mTc-MAG3 renograms were performed in patients with clinical justification for this exam, and NORA20, NORAPMi and NORAPMt values were calculated using a software developed for renograms processing. This project allowed us to obtain reference values for paediatric and adult patients. It also suggests that visualization of gallbladder does not interfere with NORA calculation. NORAPMi and NORAPMt differ from each other except for obstructed kidneys. Moreover, the distinction between dilated and obstructed kidneys through drainage analysis is only possible with NORAPMt, so in these cases it is very important to acquire a post-micturition image between 50 and 60 minutes after the beginning of the dynamic study.
The 99mTc-MAG3 renogram allows functional evaluation of the urinary system in paediatric and adult patients. The protocol for performing this exam must be standardized, according to international recommendations. The most recent guidelines advise that the evaluation be performed through two indicators: relative renal function (RRF) and renal tracer excretion. Thus, Normalized Residual Activity (NORA) has emerged, it is the one indicated to evaluate drainage, and represents the renal counts that are still remaining in the kidney at any moment, divided by the renal counts present in the second minute of the study. It can be calculated at the end of the dynamic study (NORA20) and at postmicturition images, obtained early after the dynamic study (NORAPMi) and later (NORAPMt). The purpose of this project was to determine NORA reference values by age group, kidney condition (normal, dilated and obstructed) and different moments of calculation. It was also intended to study the influence of gallbladder on parameter calculation, and evaluate the differences between NORAPMi and NORAPMt and their impact on obstruction diagnosis. To achieve these objectives, 99mTc-MAG3 renograms were performed in patients with clinical justification for this exam, and NORA20, NORAPMi and NORAPMt values were calculated using a software developed for renograms processing. This project allowed us to obtain reference values for paediatric and adult patients. It also suggests that visualization of gallbladder does not interfere with NORA calculation. NORAPMi and NORAPMt differ from each other except for obstructed kidneys. Moreover, the distinction between dilated and obstructed kidneys through drainage analysis is only possible with NORAPMt, so in these cases it is very important to acquire a post-micturition image between 50 and 60 minutes after the beginning of the dynamic study.
Description
Trabalho final de mestrado para obtenção do grau de mestre em Engenharia Biomédica
Keywords
Renograma Renogram Drenagem Drainage Rim Kidney Vesícula biliar Gallbladder Atividade residual normalizada Normalized residual activity NORA
Citation
BENTO, Bianca Correia - Valores de referência para cálculos da atividade residual normalizada em renogramas com 99mTc-MAG3. Lisboa: Instituto Superior de Engenharia de Lisboa - Escola Superior de Tecnologia da Saúde de Lisboa, 2018. Dissertação de mestrado.
Publisher
Instituto Superior de Engenharia de Lisboa - Escola Superior de Tecnologia da Saúde de Lisboa