Avaliação comparativa entre a mamografia digital e mamografia em filme: revisão sistemática e metanálise

CONTEXT AND OBJECTIVE: Mammography is the best method for breast-cancer screening and is capable of reducing mortality rates. Studies that have assessed the clinical impact of mammography have been carried out using film mammography. Digital mammography has been proposed as a substitute for film mammography given the benefits inherent to digital technology. The aim of this study was to compare the performance of digital and film mammography. DESIGN: Systematic review and meta-analysis. METHOD: The Medline, Scopus, Embase and Lilacs databases were searched looking for paired studies, cohorts and randomized controlled trials published up to 2009 that compared the performance of digital and film mammography, with regard to cancer detection, recall rates and tumor characteristics. The reference lists of included studies were checked for any relevant citations. RESULTS: A total of 11 studies involving 190,322 digital and 638,348 film mammography images were included. The cancer detection rates were significantly higher for digital mammography than for film mammography (risk relative, RR = 1.17; 95% confidence interval, CI = 1.06-1.29; I² = 19%). The advantage of digital mammography seemed greatest among patients between 50 and 60 years of age. There were no significant differences between the two methods regarding patient recall rates or the characteristics of the tumors detected. CONCLUSION: The cancer detection rates using digital mammography are slightly higher than the rates using film mammography. There are no significant differences in recall rates between film and digital mammography. The characteristics of the tumors are similar in patients undergoing the two methods.CONTEXTO E OBJETIVO: A mamografia é o melhor método para rastreamento do câncer de mama, capaz de reduzir a mortalidade. Os estudos que avaliam seu impacto clínico foram realizados com mamografia em filme. A mamografia digital é proposta para substituir a mamografia em filme com benefícios inerentes à tecnologia digital. O objetivo do estudo foi comparar o desempenho da mamografia digital com a mamografia em filme. TIPO DE ESTUDO: Revisão sistemática e metanálise. MÉTODO: Foram pesquisadas as bases Medline, Scopus, Embase e Lilacs, buscando-se por estudos pareados, coortes e ensaios clínicos randomizados comparando a mamografia digital e a mamografia em filme, quanto à taxa de detecção de câncer, de reconvocação e características dos tumores, publicados até 2009. As referências dos estudos incluídos foram verificadas em busca de citações relevantes. RESULTADOS: Foi incluído um total de 11 estudos, somando 190.322 mamografias digitais e 638.348 em filme. A taxa de detecção do câncer pela mamografia digital foi significantemente maior (risco relativo, RR: 1,17 [95% intervalo de confiança, IC = 1,06-1,29 I² = 19%]) do que pela mamografia em filme. A vantagem da mamografia digital parece maior em pacientes entre 50 e 60 anos. Não houve diferenças significantes nas taxas de reconvocação de pacientes e nas características dos tumores encontrados. CONCLUSÃO: A mamografia digital apresenta taxa de detecção de câncer pouco maior que a mamografia em filme. Não há diferenças significantes nas taxas de reconvocação entre a mamografia digital e a em filme. As características dos tumores são semelhantes em pacientes em ambos os métodos.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo (UNIFESP) Department of Diagnostic ImagingUniversidade Federal de São Paulo (UNIFESP)Universidade Federal de São Paulo (UNIFESP) Department of MedicineUNIFESP, Department of Diagnostic ImagingUNIFESP, Department of MedicineSciEL

Initial clinical evaluation of observer performance using a tablet computer with a 4K high-resolution display for detection of breast cancer by digital mammography

Purpose:To compare observer performance using medical‐purpose 5‐megapixel liquid crystal display monitors (5‐MP LCDs) and a tablet PC with a 4K high‐resolution display for detection of breast cancer by digital mammography. Materials and methods: Mammograms from 40 patients with primary breast cancer (18 mass, 16 microcalcifications, 3 artificial distortions, and 3 focal asymmetries) and 60 control patients were consecutively collected. Four experienced radiologists assessed 100 mammograms to rate using the BI‐RADS lexicon. The BI‐RADS assessments were subjected to receiver operating characteristic (ROC) curve analysis. Also, the observers assessed the image quality in terms of brightness, contrast, sharpness, and noise using 5‐step Likert scale. Results: The average under the curve (AUC) values for use of the 5‐MP LCDs and 4K monitors were 0.921 and 0.936; the difference between them was small and not significant. In terms of image quality, the 4K was rated better for brightness, contrast, and sharpness. Conclusion: Observer performance for detecting breast cancer on a 4K tablet PC with a high‐resolution display is similar to that using a 5‐MP LCD. This appears adequate for displaying mammograms of diagnostic quality and could be useful for patient consultations, clinical demonstrations, or educational and teaching purposes

Digital mammography, cancer screening: Factors important for image compression

The use of digital mammography for breast cancer screening poses several novel problems such as development of digital sensors, computer assisted diagnosis (CAD) methods for image noise suppression, enhancement, and pattern recognition, compression algorithms for image storage, transmission, and remote diagnosis. X-ray digital mammography using novel direct digital detection schemes or film digitizers results in large data sets and, therefore, image compression methods will play a significant role in the image processing and analysis by CAD techniques. In view of the extensive compression required, the relative merit of 'virtually lossless' versus lossy methods should be determined. A brief overview is presented here of the developments of digital sensors, CAD, and compression methods currently proposed and tested for mammography. The objective of the NCI/NASA Working Group on Digital Mammography is to stimulate the interest of the image processing and compression scientific community for this medical application and identify possible dual use technologies within the NASA centers