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Advisor(s)
Abstract(s)
RESUMO: Objetivos – Determinar a sensibilidade e especificidade das ponderações Difusão (DWI) e T2 Fluid-Attenuated Inversion Recovery (FLAIR) na avaliação de lesões da substância branca (SB) e verificar em que medida se complementam, por forma a criar um conjunto de boas práticas na RM cranioencefálica de rotina. Metodologia – Recorrendo-se a uma metodologia quantitativa, efetuou-se uma análise retrospetiva da qual foram
selecionados 30 pacientes, 10 sem patologia e 20 com patologia (2 com EM, 7 com Leucoencefalopatia, 6 com doença microangiopática e 5 com patologia da substância branca indefinida). Obteve-se uma amostra de 60 imagens, nomeadamente: 30 imagens ponderadas em DWI e 30 em T2 FLAIR. Recorrendo ao programa Viewdex®, três observadores avaliaram um conjunto de imagens segundo sete critérios: visibilidade, deteção, homogeneidade, localização, margens e dimensões da lesão e capacidade de diagnóstico. Com os resultados obtidos recorreu-se ao cálculo de sensibilidade e especificidade pelas Curvas
ROC, bem como à análise estatística, nomeadamente, Teste-T, Índice de Concordância
Kappa e coeficiente de correlação de Pearson entre as variáveis em estudo. Resultados – Os resultados de sensibilidade e de especificidade obtidos para a ponderação T2 FLAIR foram superiores (0,915 e 0,038, respetivamente) aos da ponderação DWI (0,08 e 0,100, respetivamente). Não se verificaram variâncias populacionais significativas. Obteve-se uma elevada correlação linear entre as variáveis com um valor r situado entre 0,8 e 0,99. Verificou-se também uma variabilidade considerável entre os observadores. Conclusões – Dados os baixos valores de sensibilidade e especificidade obtidos para a DWI, sugere-se que esta deva ser incluída no protocolo de rotina de crânio como auxiliar no diagnóstico diferencial com outras patologias.
ABSTRACT: Objectives – To determine the sensitivity and specificity of diffusion weighted (DWI) and Fluid-Attenuated Inversion Recovery (T2 FLAIR) in the evaluation of white matter lesions and to verify what is his extended complement in order to create a set of best practices in the MRI routine of the brain. Methodology – Was carried out a quantitative study with a retrospective analysis. From database, were selected 30 patients, 20 with and 10 without disease. We obtained a sample of 60 images, including 30-weighted images of T2 FLAIR and 30 of DWI. Using the program Viewdex®, the set of images were observed by three observers. The images were assessed according seven criteria: visibility, detection, consistency, location, size and margins of the lesion and diagnostic capability. We used the calculation of sensitivity and specificity by ROC curves, as well as statistical analysis, namely, T-test, Kappa index and the Pearson’s correlation coefficient between the variables under study. Results – The sensitivity and specificity obtained for the weighted T2 FLAIR were higher (0.915 and 0.038 respectively) to the weighting DWI (0.08 and 0.100 respectively). There were no significant population variances. We obtained a high linear correlation between variables with an r value located between 0.8 and 0.99. There was a considerable variability among observers. Conclusions – Although the values of sensitivity and specificity for DWI have been lower than expected, we suggest that this sequence should be included in the routine protocol of the brain to help the differential diagnosis with other pathologies.
ABSTRACT: Objectives – To determine the sensitivity and specificity of diffusion weighted (DWI) and Fluid-Attenuated Inversion Recovery (T2 FLAIR) in the evaluation of white matter lesions and to verify what is his extended complement in order to create a set of best practices in the MRI routine of the brain. Methodology – Was carried out a quantitative study with a retrospective analysis. From database, were selected 30 patients, 20 with and 10 without disease. We obtained a sample of 60 images, including 30-weighted images of T2 FLAIR and 30 of DWI. Using the program Viewdex®, the set of images were observed by three observers. The images were assessed according seven criteria: visibility, detection, consistency, location, size and margins of the lesion and diagnostic capability. We used the calculation of sensitivity and specificity by ROC curves, as well as statistical analysis, namely, T-test, Kappa index and the Pearson’s correlation coefficient between the variables under study. Results – The sensitivity and specificity obtained for the weighted T2 FLAIR were higher (0.915 and 0.038 respectively) to the weighting DWI (0.08 and 0.100 respectively). There were no significant population variances. We obtained a high linear correlation between variables with an r value located between 0.8 and 0.99. There was a considerable variability among observers. Conclusions – Although the values of sensitivity and specificity for DWI have been lower than expected, we suggest that this sequence should be included in the routine protocol of the brain to help the differential diagnosis with other pathologies.
Description
Keywords
Radiologia DWI T2 FLAIR Ressonância magnética Lesão da substância branca Radiology Diffusion MRI Magnetic resonance White matter disease
Citation
Campos C, Silva R, Ribeiro M, Lança L. Lesões da substância branca por ressonância magnética: uma avaliação entre as ponderações DWI e T2 FLAIR. Saúde & Tecnologia. 2013;(9):16-23.