Thesis (M.S.)--University of Wisconsin-Madison, 1992. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 67-72).

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Made available in DSpace on 2014-06-11T19:29:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-30Bitstream added on 2014-06-13T20:20:20Z : No. of bitstreams: 1 teixeira_mbr_me_botfm.pdf: 140784 bytes, checksum: 5554bd1ea0e3baa8524095bde2e04e33 (MD5) / Fundação de Ensino e Pesquisa em Ciências da Saúde (FEPECS) / Objetivo: Determinar o valor preditivo positivo para malignidade de lesões mamárias classificadas nas subcategorias 4A, 4B e 4C do sistema BI-RADS® pela correlação entre os achados mamográficos e histopatológicos. Sujeitos e métodos: Estudo analítico-descritivo de 89 pacientes submetidas à core biopsy e biópsia cirúrgica com e sem estereotaxia, que possuíam mamografias classificadas nas subcategorias 4A, 4B e 4C do BI-RADS® 4ª edição. Os achados mamográficos foram correlacionados com os diagnósticos histológicos das lesões, calculando-se o valor preditivo positivo para malignidade em cada subcategoria. Resultados: Dentre as 89 pacientes avaliadas foram diagnosticados 50 casos de câncer de mama (56,2%), sendo 9 na subcategoria 4A, 21 na 4B e 20 na 4C. Os valores preditivos positivos encontrados foram, respectivamente, 25,7 %, 63,6 % e 95,2 % para as subcategorias 4A, B e C. O nódulo espiculado foi o achado mais relacionado à doença maligna. Conclusão: Houve elevação progressiva do VPP nas subcategorias 4A, 4B e 4C do BIRADS ® / Objective: To determine the positive predictive value for malignancy of mammary lesions classified in the subcategories 4A, 4B and 4C of the BI-RADS® system based on the correlation between the mammographic and histopathological findings. Subjects and methods: Analytical-descriptive study of 89 patients submittted to core biopsy and surgical biopsy with and without stereotatic localization, that possessed mammograms classified as subcategories 4A, 4B and 4C of the BI-RADS® 4th edition. The mammographic findings were correlated to the histological diagnosis of the lesions, then calculating the positive predictive value for malignancy in each subcategory. Results: Among the 89 evaluated patients, 50 were diagnosed as breast cancer cases (56.2%), of which 9 in subcategory 4A, 21 in 4B and 20 in 4C. The positive predictive values found were, respectively, 25.7%, 63.6% and 95,2% for the 4A, B and C subcategories. The spiculated nodule was the finding most related to the malignant disease. Conclusion: There has been progressive elevation of the PPV in subcategories 4A, 4B and 4C of BI-RADS®

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Orientadores: Gustavo Antonio de Souza, Luis Otavio Sarian / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-11T03:29:01Z (GMT). No. of bitstreams: 1 Kestelman_FabiolaProcaci_M.pdf: 577232 bytes, checksum: acf1199f373751447b51be36a9c1cb18 (MD5) Previous issue date: 2008 / Resumo: Objetivo: Determinar o valor preditivo positivo das categorias 4A, 4B e 4C da 4ª edição do BI-RADS e determinar a variação interobservador desta classificação em lesões submetidas à biópsia cirúrgica. Métodos: Este estudo retrospectivo foi conduzido no Instituto Nacional de Câncer (INCA), Rio de Janeiro, Brasil. Os casos para análise foram selecionados no banco de dados do setor de radiologia, entre mulheres submetidas à marcação pré-cirúrgica para biópsia cirúrgica entre janeiro de 1999 e dezembro de 2002, que foram previamente classificadas como BIRADS 4. As mamografias foram revisadas por três radiologistas especializados em radiologia mamária. Os avaliadores classificaram as lesõs considerando a probabilidade de malignidade, dentro da categoria 4, em 4A, 4B e 4C. Para a análise estatética, foi realizado um consenso a partir dos resultados dos três radiologistas. A variação interobservador foi calculada utilizando o índice de kappa ponderado. Resultados: De 775 lesõs, o resultado consensual mostrou 235 (30,3%) mamografias classificadas como 4A, 338 (43,6%) como 4B e o restante 161 (20,8%) como 4C. Os radiologistas não obtiveram consenso em 41 (5,3%) lesões. A concordância geral entre os avaliadores foi moderada (?=0,44), variando entre ?=0,38 considerando os radiologistas dois e tr? e ?=0,54 considerando os radiologistas um e dois. A concordância variou de mínima (categoria 4B, k= 0,09) a pobre, considerando as categorias 4A e 4C. A proporção de lesões nos grupos 4A, 4B e 4C foi similar e o VPP foi progressivo (23,0%, 47,6% e 72,7%, respectivamente). Conclusão: O VPP das categorias 4A, 4B and 4C foi progressivo e a concord?cia entre os observadores foi moderada / Abstract: Purpose: To determine the predictive positive value of BI-RADS 4th edition categories 4A, 4B and 4C and determine the inter-observer variability for lesion on which biopsies had been performed. Methods: This cross-sectional study was conducted at the National Institute of Cancer (INCA), Rio de Janeiro, Brazil. Cases for analysis were selected from the medical records among women who were submitted to breast needle localization and diagnostic surgical biopsy, from January 1999 to December 2002, and which had been previously categorized as BIRADS 4. The mammograms were reviewed by three senior breast imaging radiologists. Readers provided a BI-RADS final assessment category to indicate the probability of malignancy in category 4. For statistical calculations, a ¿consensus¿ variable was created using the outputs from the three assessors. Interobserver variability for each subcategory was determined using the weighted kappa statistic. Results: Of 775 lesions, ¿consensual¿ assessment rendered 235 (30.3%) mammograms classified as 4A, 338 (43.6%) as 4B and the remainder 161 (20.8%) as 4C. Radiologists did not reach a consensus in 41 (5.3%) exams. Overall agreement between raters was moderate (?=0.44), ranging from ?=0.38 between raters two and three to ?=0.54 between radiologists one and two. Agreement between raters ranged from slight (category 4B, k=0.09) to fair, considering categories 4A and 4C. In BI-RADS 4B and 4C groups, the proportion of each abnormality in the whole group was similar to that in 4A, but the PPV were higher. Conclusions: The PPV for subcategories 4A, 4B and 4C was progressive and the agreement between readers was moderate. Key words: Breast cancer, mammography, BI-RADS / Mestrado / Tocoginecologia / Mestre em Tocoginecologia

Mammographic techniques used for screening programmes need to be of the highest quality; hence, the need of a good phantom to mimic breast response to radiation. The phantom materials must be sensitive to small changes in the mammography system and provide a means of evaluating the absorbed dose to the breast. These materials have to provide the same attenuation properties as the real tissues being simulated, for the radiation modalities being investigated. Cross-linked hydrophilic copolymers have the potential to be good phantom materials for the breast as their elemental compositions are similar to soft tissue. Two types of hydrophilic copolymer materials used in this study were designated as ED1S and ED4C. They were made from a certain proportionate mixture of methyl methacrylate and vinyl pyrrolidone. The physical properties of the materials such as liquid uptake and dimensional changes in hydration and dehydration processes were studied. The equilibrium water content of ED1S and ED4C fully hydrated in water was 55% and 70% respectively. The samples underwent distortion when dehydrated and a volume approximation formula for the dehydrated samples was derived. The linear attenuation coefficient and the mass attenuation coefficient of the hydrophilic copolymer materials at photon energies in the mammographic energy region were determined. Both a single beam transmission method and a photon transmission tomography method were used. The results were compared with XCOM calculated attenuation coefficients of water and average breasts using the elemental composition found in the literature. It was found that the mass attenuation coefficient of dry hydrophilic copolymer samples closely fit the XCOM calculated old-age breast (Breast 3) and samples fully hydrated in water fit the calculated young-age breast (Breast 1). Measurements were also carried out to determine the linear attenuation coefficient of normal and abnormal breast tissues at four photon energies in the mammographic energy region. The values found were in good accord with calculated average breast values. However, more studies need to be done as only three samples were used. The electron density of the hydrophilic copolymer materials was determined by using the Compton scattering technique. The electron density for dry ED1S sample was (3.1 +/- 0.4) x 1023 electrons per cm3 and for dry ED4C was (4.4 +/- 0.4) x 1023 electrons per cm3.

Digital breast tomosynthesis is a new technology that provides three-dimensional information of the breast and makes it possible to distinguish the cancer from overlying breast tissues. We are dedicated to optimizing image reconstruction and imaging configuration for a new multi-beam parallel digital breast tomosynthesis prototype system. Several commonly used algorithms from the typical image reconstruction models which were used for iso-centric tomosynthesis systems were investigated for our multi-beam parallel tomosynthesis imaging system. The representative algorithms, including back-projection (BP), filtered back-projection (FBP), matrix inversion tomosynthesis reconstruction (MITS), maximum likelihood expectation maximization (MLEM), ordered-subset maximum likelihood expectation maximization (OS-MLEM), simultaneous algebraic reconstruction technique (SART), were implemented to fit our system design. An accelerated MLEM algorithm was proposed, which significantly reduced the running time but had the same image quality. Furthermore, two statistical variants of BP reconstruction were validated for our tomosynthesis prototype system. Experiments based on phantoms and computer simulations show that the prototype system combined with our algorithms is capable of providing three-dimensional information of the objects with good image quality and has great potentials to improve digital breast tomosynthesis technology. Four methodologies were employed to optimize the reconstruction algorithms and different imaging configurations for the prototype system. A linear tomosynthesis imaging analysis tool was used to investigate blurring-out reconstruction algorithms. Computer simulations of sphere and wire objects aimed at the performance of out-of-plane artifact removal. A frequency-domain-based methodology, relative NEQ(f) analysis, was investigated to evaluate the overall system performance based on the propagation of signal and noise. Conclusions were made to determine the optimal image reconstruction algorithm and imaging configuration of this new multi-beam parallel digital breast tomosynthesis prototype system for better image quality and system performance.

Breast Cancer is the second most common cancer in Sweden. More treatment options are available with a higher chance of survival if Breast cancer is diagnosed early. WHO has recommended performing Breast Cancer screenings on women even before they develop any symptoms. In Sweden, all women between the age of 40 and 74 years are called for a Breast Cancer Screening examination every two years. However, all of the called out women are not appearing for Breast screening therefore the purpose of this degree project is to analyze the possible benefits of setting up Mobile Mammography Units (MMUs) in Sweden. This thesis focuses on need-analysis, cost-analysis, image quality, and quality of care in MMUs compared to fixed units and if MMUs can be used as a tool for dispersal of knowledge regarding preventive care for cancer. Further, long waiting queues is one of the major concern and underperformed area in Sweden. Since the enactment of Cancer Care Pathways in Sweden, long waiting queues for patients having non-cancer diseases have been the most frequently mentioned risk in the regional status reports. This study, therefore, aims to analyze if mammography screening in hospitals is adding up to the long waiting ques for other patients or not. This study followed a qualitative setting where several semi-structured interviews were conducted with members of the National workgroup of mammography in Sweden, and an abductive inductive approach was followed for the data collection and analysis. The results of the study concluded that Mobile mammography units are only beneficial for areas with demographic issues. Mobile mammography units are resource-demanding therefore it is better to invest in fixed units for areas where there are no traveling issues. The mammography unit in a hospital is a separate department and does not affect any other patient by being in the hospital hence not resulting in the “Crowding out effect”. Regarding the Image quality and quality of care, it is similar in both the fixed and mobile units, apart from the quality of care for disabled women who must visit the fixed unit and hence are deprived of close care. A proper cost-analysis, with exact figures, for both mobile and fixed mammography units was not found during this study therefore it could not be concluded if MMUs are cost-effective or not. Also, if Mobile Mammography Units are to be used as a tool for the dispersal of knowledge regarding the prevention of cancer, there will be a need to hire extra staff who can perform this job. / Bröstcancer är den näst vanligaste cancerformen i Sverige. Fler behandlingsalternativ finns tillgängliga med högre chans att överleva om bröstcancer diagnostiseras tidigt. WHO har rekommenderat att utföra bröstcancerscreeningar på kvinnor även innan de utvecklar några symtom. I Sverige kallas alla kvinnor mellan 40 och 74 år till en bröstcancerundersökning vartannat år. Alla kvinnor som bjuds in till undersökning dyker dock inte upp, därför är syftet med detta examensarbete att analysera möjliga fördelar med att sätta upp mobila mammografienheter (MMU) i Sverige. Långa väntetider är ett stort problem i Sverige, även för dessa patienter som inte har cancer eller tecken på cancer. Denna studie syftar därför till att analysera om mammografiscreening på sjukhus ökar eller minskar de långa väntetiderna för andra patienter som inte är drabbade av cancern. Resultat av studien visar att mobila mammografienheter endast är fördelaktiga för områden med demografiska problem. Mobila mammografienheter är resurskrävande, därför är det bättre att investera i fasta enheter för områden där det inte finns några reseproblem. Också Mammografienheten på ett sjukhus är en separat avdelning och bör inte påverka antal mängder patienter på ett sjukhus. Vi kunde inte fastställa kostnader för vare sig mobila eller fasta mammografienheter under denna studie. Därmed kan slutsatsen inte avgöras om det är förmånligt med mobila mammografienheter eller inte. Men däremot är en sak säker, det kommer att behövas att anställa fler personal.

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