Utilização da sequência de difusão por ressonância magnética no diagnóstico não invasivo de obstrução de vias biliares
Data
2021-10-07
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Objetivo: Avaliar a utilidade da sequência de difusão (DWI) por ressonância magnética (RM) na diferenciação entre vias biliares com e sem obstrução nos pacientes que realizaram colangiopancreatografia por ressonância magnética (CPRM). Métodos: Foram avaliados retrospectivamente 84 pacientes, 40 homens e 44 mulheres (idade média: 56,4 ± 15,1 anos), encaminhados pela disciplina de Gastroenterologia Cirúrgica da Escola Paulista de Medicina – UNIFESP, que realizam RM com protocolo de CPRM e DWI. Todos os pacientes possuíam os exames laboratoriais de avaliação de obstrução de via biliar até 24 horas da realização do exame de imagem. Os pacientes foram divididos e separados em dois grupos, 58 com alteração de exames laboratoriais, chamado de grupo obstruído (GO) e 26 com exames laboratoriais normais, grupo não obstruído (GNO). Os exames laboratoriais realizados foram bilirrubina total, fosfatase alcalina e gama glutamil transferase. O exame de CPRM foi realizado com sequência de DWI (0, 50, 500 e 700) e no mapa ADC foi calculada a mediana, esta correlacionada com os exames laboratoriais e grau de dilatação da via biliar. O grau de dilatação da via biliar foi quantificado em ausente, moderado e acentuado. O cálculo da mediana do mapa ADC (b700) foi realizado com um ROI no interior da via biliar distal, em três níveis distintos, e foi calculada a curva ROC. Foi avaliada a persistência de hipersinal na sequência de DWI nos valores de b500 e b700. Os valores de bilirrubina foram correlacionados com os do mapa ADC calculados na via biliar e com a persistência do hipersinal na sequência de DWI no valor de b700. Para análise estatística foram utilizados os testes t de Student, qui-quadrado e Wilcoxon-Mann-Whitney. Resultados: No GO, 15 pacientes apresentaram dilatação acentuada, 24 moderada e 19 sem dilatação significativa. No GNO, 23 pacientes sem dilatação significativa e 3 apresentaram moderada dilatação; 4 pacientes do GNO apresentaram persistência do alto sinal no b700, enquanto que 38 pacientes do GO mostraram esta persistência. Houve correlação entre o grau de dilatação das vias biliares e os valores de bilirrubina com a persistência do hipersinal em b700 e os valores do mapa ADC. O valor de corte do mapa ADC calculado (353 x 10–6 mm²/s) permitiu diferenciar os GO e GNO (sensibilidade = 92,3%, especificidade = 81,0% e acurácia = 91,9%) Conclusão: A sequência de difusão por RM é capaz de diferenciar pacientes com obstrução de vias biliares de pacientes sem obstrução de vias biliares, independente do grau de dilatação. Há correlação com o quadro clínico e laboratorial.
Objective: This study sought to evaluate the role of diffusion-weighted imaging (DWI) in differentiation between obstructed and unobstructed bile ducts in patients undergoing magnetic resonance imaging (MRI). Methods: Eighty-four patients undergoing MRI with DWI (0–50–500–700) were evaluated and divided into two groups: 58 with abnormal laboratory tests (obstructed group) and 26 with normal laboratory values (unobstructed group). Laboratory tests were total bilirubin, alkaline phosphatase and gamma-glutamyltransferase. Median ADC values were calculated and correlated with laboratory tests and degree of bile-duct dilatation (absent, moderate, or severe). The persistence of signal on DWI (b500 and b700) in the biliary tract was evaluated. Bilirubin values were tested for correlation with bile-duct ADC values and persistence of b700 signal. ADC maps were plotted for three levels of the biliary tree, and a receiver operating characteristic (ROC) curve was calculated. Results: In the obstructed group, 15 patients had severe dilatation, 24 had moderate dilatation, and 19 had no appreciable dilatation; 38 patients had persistent signal on b700 images. In the unobstructed group, 23 patients had no dilatation and 3 had moderate dilatation; 4 patients had persistent signal on b700 images. Correlation was found between bilirubin levels, persistence of b700 signal, and ADC map values. The calculated ADC map cutoff value (353 x 10-6 mm2 /s) was able to differentiate the obstructed and unobstructed groups with 92.3% sensitivity and 81.0% specificity. Conclusions: DWI is able to distinguish patients with obstructed versus unobstructed bile ducts, regardless of the degree of dilatation, correlating with clinical and laboratory findings.
Objective: This study sought to evaluate the role of diffusion-weighted imaging (DWI) in differentiation between obstructed and unobstructed bile ducts in patients undergoing magnetic resonance imaging (MRI). Methods: Eighty-four patients undergoing MRI with DWI (0–50–500–700) were evaluated and divided into two groups: 58 with abnormal laboratory tests (obstructed group) and 26 with normal laboratory values (unobstructed group). Laboratory tests were total bilirubin, alkaline phosphatase and gamma-glutamyltransferase. Median ADC values were calculated and correlated with laboratory tests and degree of bile-duct dilatation (absent, moderate, or severe). The persistence of signal on DWI (b500 and b700) in the biliary tract was evaluated. Bilirubin values were tested for correlation with bile-duct ADC values and persistence of b700 signal. ADC maps were plotted for three levels of the biliary tree, and a receiver operating characteristic (ROC) curve was calculated. Results: In the obstructed group, 15 patients had severe dilatation, 24 had moderate dilatation, and 19 had no appreciable dilatation; 38 patients had persistent signal on b700 images. In the unobstructed group, 23 patients had no dilatation and 3 had moderate dilatation; 4 patients had persistent signal on b700 images. Correlation was found between bilirubin levels, persistence of b700 signal, and ADC map values. The calculated ADC map cutoff value (353 x 10-6 mm2 /s) was able to differentiate the obstructed and unobstructed groups with 92.3% sensitivity and 81.0% specificity. Conclusions: DWI is able to distinguish patients with obstructed versus unobstructed bile ducts, regardless of the degree of dilatation, correlating with clinical and laboratory findings.
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Citação
Paro EDL, Puchnick A, Szejnfeld J, Goldman SM. Use of diffusion-weighted imaging in the noninvasive diagnostic of obstructed biliary ducts. Abdom Radiol (NY). 2021 Jan;46(1):268-279. doi: 10.1007/s00261-020-02636-x. Epub 2020 Jul 14. PMID: 32666232.