Dependence of IVIM-DWI estimations on acquisition parameters

Detalhes bibliográficos
Autor(a) principal: Cachola, Gonçalo da Silva Brissos Chimelas
Data de Publicação: 2013
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10362/10914
Resumo: Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica
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spelling Dependence of IVIM-DWI estimations on acquisition parametersNonalcoholic fatty liver diseaseIntravoxelIncoherent motion imagingDiffusion imagingb-value distributionDissertação para obtenção do Grau de Mestre em Engenharia BiomédicaNonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver conditions in the Western world. It is normally associated with health disorders such as obesity, diabetes and hypertriglyceridemia. The gold standard for the diagnosis and staging of NAFLD is liver biopsy, which is highly invasive and is associated with high morbidity and inherent sampling error. Intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) is able to distinguish between true molecular diffusion and the pseudo-random motion of water molecules inside micro vessels. IVIM-DWI has emerged in the recent years as a possible alternative to probe tissue changes in NAFLD. However few studies have addressed the problem of the dependence of IVIM-DWI parameters on pulse sequence parameters. In order to study this dependence, two studies were carried-out: 1) A simulation study, where we studied the influence of acquisition parameters on the error and bias associated with IVIM-DWI parameters; 2) In-vivo study in order to test the performance of the b-value sequences derived from the simulation studies. Results showed that the parameter which is more affected by the acquisition parameters is D*. Furthermore, it was also shown that the higher the number of b-values used to sample the data, the better the estimation of IVIM-DWI parameters is. However, after a certain number of points and for low SNRs, the effect of noise in extra b-values counteracts the effect of having more data points. It was also shown that the b-value sequence that is used to sample the data greatly influences IVIM-DWI estimations. We concluded that the conventionally used b-value sequence does not provide optimum IVIM-DWI estimations. Furthermore, results show that different weights should be attributed to each IVIM-DWI parameter in order to obtain a better performance of the optimized b-value sequence. Also, it was seen that the influence of T2 relation effects should be accounted for in the IVIM-DWI model. Lastly, our study showed that in the presence of steatosis, the value D* significantly decreased while D only slightly decreased. However, the differences between patients with steatosis and healthy controls were extremely influenced by the number of b-values used, leading to different diagnosis depending on the number of b-values used in the acquisition.Faculdade de Ciências e TecnologiaGonçalves, SóniaSecca, MárioRUNCachola, Gonçalo da Silva Brissos Chimelas2013-12-20T12:01:33Z20132013-01-01T00:00:00Zinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://hdl.handle.net/10362/10914enginfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2024-03-11T03:44:58Zoai:run.unl.pt:10362/10914Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-20T03:19:50.461914Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Dependence of IVIM-DWI estimations on acquisition parameters
title Dependence of IVIM-DWI estimations on acquisition parameters
spellingShingle Dependence of IVIM-DWI estimations on acquisition parameters
Cachola, Gonçalo da Silva Brissos Chimelas
Nonalcoholic fatty liver disease
Intravoxel
Incoherent motion imaging
Diffusion imaging
b-value distribution
title_short Dependence of IVIM-DWI estimations on acquisition parameters
title_full Dependence of IVIM-DWI estimations on acquisition parameters
title_fullStr Dependence of IVIM-DWI estimations on acquisition parameters
title_full_unstemmed Dependence of IVIM-DWI estimations on acquisition parameters
title_sort Dependence of IVIM-DWI estimations on acquisition parameters
author Cachola, Gonçalo da Silva Brissos Chimelas
author_facet Cachola, Gonçalo da Silva Brissos Chimelas
author_role author
dc.contributor.none.fl_str_mv Gonçalves, Sónia
Secca, Mário
RUN
dc.contributor.author.fl_str_mv Cachola, Gonçalo da Silva Brissos Chimelas
dc.subject.por.fl_str_mv Nonalcoholic fatty liver disease
Intravoxel
Incoherent motion imaging
Diffusion imaging
b-value distribution
topic Nonalcoholic fatty liver disease
Intravoxel
Incoherent motion imaging
Diffusion imaging
b-value distribution
description Dissertação para obtenção do Grau de Mestre em Engenharia Biomédica
publishDate 2013
dc.date.none.fl_str_mv 2013-12-20T12:01:33Z
2013
2013-01-01T00:00:00Z
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10362/10914
url http://hdl.handle.net/10362/10914
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Faculdade de Ciências e Tecnologia
publisher.none.fl_str_mv Faculdade de Ciências e Tecnologia
dc.source.none.fl_str_mv reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron:RCAAP
instname_str Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
instacron_str RCAAP
institution RCAAP
reponame_str Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
collection Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
repository.name.fl_str_mv Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação
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