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Processo shimming em ressonância magnética: uma revisão sistemática
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Abstract(s)
Introdução: O shimming é o processo que visa diminuir a inomogeneidade do campo magnético. O termo surge da "placa", componente específica utilizada para corrigir as imperfeições do campo magnético. Este processo pode ser feito de duas formas principais: shimming passivo, introduzindo componentes metálicos de formato, peso e tamanho adequados em locais específicos, para corrigir distorções de campo magnético e shimming ativo, que utiliza bobinas elétricas de maneira estratégica para produzir campos magnéticos corretivos. Objetivos: A investigação procurou identificar estudos com o intuito de descrever o processo shimming e a sua utilização na correção das inomogeneidades do campo magnético principal. Como objetivos secundários procurou-se verificar na literatura a relação direta entre o processo shimming e a importância que esta possui na compensação de inomogeneidades, bem como na qualidade de imagem final obtida. Métodos: Para a elaboração desta dissertação, a metodologia selecionada foi a revisão sistemática, através da análise de artigos científicos publicados nas bases de dados PubMed, a Cochrane Library, a ScienceDirect e a SciELO. Nas respetivas bases de dados, foram utilizadas as palavras-chave: “shimming AND magnetic resonance”, “inhomogeneity AND shimming”. Resultados: Após uma pesquisa em diferentes bases de dados, os artigos foram triados no Mendeley, e 27 estudos foram selecionados para esta revisão sistemática, seguindo algumas diretrizes do protocolo Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Conclusões: A compilação da análise dos estudos, mostram que o shimming possui viabilidade para corrigir as inomogeneidades do campo magnético principal. Cientificamente, os estudos demonstraram a importância do shimming para as imagens de ressonância magnética, a não uniformidade do campo magnético pode causar perda indesejada de sinal, e distorções de imagem.
ABSTRACT: Introduction: Shimming is the process that aims to reduce the inhomogeneity of the magnetic field. The term originates from the concept of "plates", a specific component used to correct imperfections in the magnetic field. This can be done in two main ways: passive shimming, introducing metal components of appropriate shape, weight, and size in specific locations, to correct magnetic field distortions, and active shimming, which uses electrical coils strategically to produce corrective magnetic fields. Objectives: The research sought to identify studies to describe the shimming process and its use in correcting inhomogeneities in the main magnetic field. As secondary objectives, we sought to verify in the literature the direct relationship between the shimming process and its importance in the compensation of inhomogeneities, as well as in the quality of the final image obtained. Methods: For the elaboration of this dissertation, the methodology selected was the systematic review, through the analysis of scientific articles published in the databases PubMed, the Cochrane Library, ScienceDirect, and SciELO. In the respective databases, the following keywords were used: “shimming AND magnetic resonance”, “inhomogeneity AND shimming”. Results: After a search in different databases, the articles were screened in Mendeley, and 27 studies were selected for this systematic review, following some guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Conclusions: The compilation of the analysis of the studies shows that shimming is viable for correcting inhomogeneities in the main magnetic field. Scientifically, studies have demonstrated the importance of shimming for magnetic resonance images, the non-uniformity of the magnetic field can cause unwanted signal loss and image distortions.
ABSTRACT: Introduction: Shimming is the process that aims to reduce the inhomogeneity of the magnetic field. The term originates from the concept of "plates", a specific component used to correct imperfections in the magnetic field. This can be done in two main ways: passive shimming, introducing metal components of appropriate shape, weight, and size in specific locations, to correct magnetic field distortions, and active shimming, which uses electrical coils strategically to produce corrective magnetic fields. Objectives: The research sought to identify studies to describe the shimming process and its use in correcting inhomogeneities in the main magnetic field. As secondary objectives, we sought to verify in the literature the direct relationship between the shimming process and its importance in the compensation of inhomogeneities, as well as in the quality of the final image obtained. Methods: For the elaboration of this dissertation, the methodology selected was the systematic review, through the analysis of scientific articles published in the databases PubMed, the Cochrane Library, ScienceDirect, and SciELO. In the respective databases, the following keywords were used: “shimming AND magnetic resonance”, “inhomogeneity AND shimming”. Results: After a search in different databases, the articles were screened in Mendeley, and 27 studies were selected for this systematic review, following some guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) protocol. Conclusions: The compilation of the analysis of the studies shows that shimming is viable for correcting inhomogeneities in the main magnetic field. Scientifically, studies have demonstrated the importance of shimming for magnetic resonance images, the non-uniformity of the magnetic field can cause unwanted signal loss and image distortions.
Description
Mestrado em Radiações Aplicadas às Tecnologias da Saúde - Área de especialização: Imagem por Ressonância Magnética
Keywords
Ressonância magnética Processo shimming Revisão sistemática Magnetic resonance Systematic review MRATES
Citation
Silva GO. Processo shimming em ressonância magnética: uma revisão sistemática [dissertation]. Lisboa: Escola Superior de Tecnologia da Saúde de Lisboa/Instituto Politécnico de Lisboa; 2024.
Publisher
Instituto Politécnico de Lisboa