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Abstract(s)
Introdução: A Non Alcoholic Fatty Liver Disease é a patologia crónica hepática mais comum nos países desenvolvidos com uma prevalência de 20-30% nos adultos e 70-91% em doentes de alto risco tais como os afetados pela síndrome metabólica. Apesar do crescimento epidémico, a NAFLD continua pouco diagnosticada, mesmo com o seu potencial evolutivo. De modo a melhorar a deteção e estadiamento da NAFLD, são necessárias técnicas não invasivas que permitam um fácil acesso e avaliação da gordura hepática. A técnica de RM codificada por desvio químico tem-se mostrado mais eficaz na quantificação da esteatose hepática, quando comparada com outros métodos não invasivos. O objetivo geral deste estudo foi avaliar o contributo das técnicas de codificação de desvio químico em Imagem por Ressonância Magnética na avaliação da esteatose hepática utilizando uma aplicação online de livre acesso. Materiais e Métodos: Foram analisados 70 exames de Ressonância Magnética, baseados nas técnicas de Dixon, com os protões em fase e fora de fase. Foi calculada a fração de gordura hepática desta amostra, através de um método quantitativo disponível numa plataforma online, desenvolvida por Philip Cheng, MD, MS, baseada nos métodos de Dixon. Foram correlacionados os resultados obtidos com os valores laboratoriais e componentes da síndrome metabólica. Resultados: Dos 70 exames incluídos no estudo, 50% da amostra (35 doentes) apresentaram valores de fração de gordura hepática superiores a 5%. Dos 35 doentes com esteatose hepática, 20 apresentaram esteatose leve (de 5% a 15%), 13 apresentaram esteatose moderada (de 15% a 30%) e 2 deles esteatose grave (>30%). Os doentes do sexo masculino apresentaram médias de fração de gordura hepática superiores às apresentadas pelo sexo feminino. Dos doentes com NAFLD, 89% apresentaram, no mínimo, um dos seguintes fatores de risco: hiperglicemia em jejum, DAS aumentado, ou dislipidemia. Os valores de correlação das diferentes variáveis com a esteatose hepática que se revelaram estatisticamente significativos, com valores de correlação moderados e positivos, foram os dos triglicéridos (ρS=0,526; p=0,01), a glicose, (ρS=0,307; p=0,05), bem como o Diâmetro Abdominal Sagital com (ρS=0,565; p=0,01). A correlação da enzima ALT com a esteatose hepática foi fraca, ρS=0,269, porém com significância estatística (p=0,05). A percentagem FF do segmento V/VIII e a %FF da média dos 3 segmentos hepáticos apresentaram uma correlação positiva forte, sendo esta a correlação mais elevada, de entre os 3 segmentos, com ρS=0,950.
ABSTRACT - Introduction: Non-Alcoholic Fatty Liver Disease is the most common chronic liver disease in developed countries with a prevalence of 20-30% in adults and 70-91% in high-risk patients such as those affected by the metabolic syndrome. Despite the epidemic growth, NAFLD remains highly underdiagnosed, despite its evolutionary potential. In order to improve the detection and staging of NAFLD, non-invasive techniques are needed to allow easy access and assessment of liver fat. The MR technique encoded by chemical shift has been shown to be superior in the quantification of hepatic steatosis when compared to other non-invasive methods. The general objective of this study was to evaluate the contribution of chemical shift techniques in Magnetic Resonance Imaging in the assessment of hepatic steatosis using an open access online application. Materials and Methods: Seventy magnetic resonance imaging exams were analyzed, based on the chemical shift technique with protons in phase and out of phase. The fat fraction of the liver in this sample was calculated using a calculator available on an online platform, developed by Philip Cheng, MD, MS, based on Dixon's methods. The results obtained were correlated with the laboratory values and components of the metabolic syndrome. Results: Of the 70 exams included in the study, 50% of the sample (35 patients) had liver fat fraction values greater than 5%. Of the 35 patients with hepatic steatosis, 20 had mild steatosis (from 5% to 15%), 13 had moderate steatosis (from 15% to 30%), and two of them had severe steatosis (> 30%). Male patients had higher hepatic fat fraction averages than women. 89% of NAFLD patients had at least one of the following risk factors: fasting hyperglycemia increased DAS or dislipidemia. The statistically significant values were triglycerides, ρ=0.526 (p<0.01), glycemia with ρ=0.307 (p<0.05), as well as the Sagittal Abdominal Diameter, which showed a positive correlation with ρ=0.565 (p<0.01). Finally, ALT was the hepatic enzyme with the most significant correlation ρ=0.269 (p<0.05). The% FF of segment V / VIII and% FF of the average of the three liver segments showed a strong positive correlation, being the strongest correlation, among the three segments, with p=0.950.
ABSTRACT - Introduction: Non-Alcoholic Fatty Liver Disease is the most common chronic liver disease in developed countries with a prevalence of 20-30% in adults and 70-91% in high-risk patients such as those affected by the metabolic syndrome. Despite the epidemic growth, NAFLD remains highly underdiagnosed, despite its evolutionary potential. In order to improve the detection and staging of NAFLD, non-invasive techniques are needed to allow easy access and assessment of liver fat. The MR technique encoded by chemical shift has been shown to be superior in the quantification of hepatic steatosis when compared to other non-invasive methods. The general objective of this study was to evaluate the contribution of chemical shift techniques in Magnetic Resonance Imaging in the assessment of hepatic steatosis using an open access online application. Materials and Methods: Seventy magnetic resonance imaging exams were analyzed, based on the chemical shift technique with protons in phase and out of phase. The fat fraction of the liver in this sample was calculated using a calculator available on an online platform, developed by Philip Cheng, MD, MS, based on Dixon's methods. The results obtained were correlated with the laboratory values and components of the metabolic syndrome. Results: Of the 70 exams included in the study, 50% of the sample (35 patients) had liver fat fraction values greater than 5%. Of the 35 patients with hepatic steatosis, 20 had mild steatosis (from 5% to 15%), 13 had moderate steatosis (from 15% to 30%), and two of them had severe steatosis (> 30%). Male patients had higher hepatic fat fraction averages than women. 89% of NAFLD patients had at least one of the following risk factors: fasting hyperglycemia increased DAS or dislipidemia. The statistically significant values were triglycerides, ρ=0.526 (p<0.01), glycemia with ρ=0.307 (p<0.05), as well as the Sagittal Abdominal Diameter, which showed a positive correlation with ρ=0.565 (p<0.01). Finally, ALT was the hepatic enzyme with the most significant correlation ρ=0.269 (p<0.05). The% FF of segment V / VIII and% FF of the average of the three liver segments showed a strong positive correlation, being the strongest correlation, among the three segments, with p=0.950.
Description
Mestrado em Radiações Aplicadas às Tecnologias da Saúde. - Área de especialização: Imagem por Ressonância Magnética
Keywords
Ressonância magnética Esteatose hepática Desvio químico Magnetic resonance Hepatic steatosis Chemical shift
Citation
Félix CP. Quantificação de esteatose hepática através de imagens de ressonância magnética: estudo retrospetivo [dissertation]. Lisboa: Escola Superior de Tecnologia da Saúde de Lisboa/Instituto Politécnico de Lisboa; 2020.
Publisher
Instituto Politécnico de Lisboa, Escola Superior de Tecnologia da Saúde de Lisboa