Mammography

About: Mammography is a research topic. Over the lifetime, 20643 publications have been published within this topic receiving 513679 citations.

Canadian National Breast Screening Study: 1. Breast cancer detection and death rates among women aged 40 to 49 years

Abstract: OBJECTIVES: To evaluate the efficacy of the combination of annual screening with mammography, physical examination of the breasts and the teaching of breast self-examination in reducing the rate of death from breast cancer among women aged 40 to 49 years on entry. DESIGN: Individually randomized controlled trial. SETTING: Fifteen urban centres in Canada with expertise in the diagnosis and treatment of breast cancer. PARTICIPANTS: Women with no history of breast cancer and no mammography in the previous 12 months were randomly assigned to undergo either annual mammography and physical examination (MP group) or usual care after an initial physical examination (UC group). The 50,430 women enrolled from January 1980 through March 1985 were followed for a mean of 8.5 years. DATA COLLECTION: Derived from the participants by initial and annual self-administered questionnaires, from the screening examinations, from the patients9 physicians, from the provincial cancer registries and by record linkage to the Canadian National Mortality Data Base. Expert panels evaluated histologic and death data. MAIN OUTCOME MEASURES: Rates of referral from screening, rates of detection of breast cancer from screening and from community care, nodal status, tumour size, and rates of death from all causes and from breast cancer. RESULTS: Over 90% of the women in each group attended the screening sessions or returned the annual questionnaires, or both, over years 2 to 5. The characteristics of the women in the two groups were similar. Compared with the Canadian population, the participants were more likely to be married, have fewer children, have more education, be in a professional occupation, smoke less and have been born in North America. The rate of screen-detected breast cancer on first examination was 3.89 per 1000 in the MP group and 2.46 per 1000 in the UC group; more node-positive tumours were found in the MP group than in the UC group. During years 2 through 5 the ratios of observed to expected cases of invasive breast cancer were 1.26 in the MP group and 1.02 in the UC group. Of the women with invasive breast cancer through to 7 years, 191 and 157 women in the MP and UC groups respectively had no node involvement, 55 and 43 had one to three nodes involved, 47 and 23 had four or more nodes involved, and 38 and 49 had an unknown nodal status. There were 38 deaths from breast cancer in the MP group and 28 in the UC group. The ratio of the proportions of death from breast cancer in the MP group compared with those in the UC group was 1.36 (95% confidence interval 0.84 to 2.21). The survival rates were similar in the two groups. The highest survival rate occurred among women whose cancer had been detected by mammography alone. CONCLUSION: The study was internally valid, and there was no evidence of randomization bias. Screening with yearly mammography and physical examination of the breasts detected considerably more node-negative, small tumours than usual care, but it had no impact on the rate of death from breast cancer up to 7 years9 follow-up from entry.

A clinical prototype for active microwave imaging of the breast

Abstract: Despite its recognized value in detecting and characterizing breast disease, X-ray mammography has important limitations that motivate the quest for alternatives to augment the diagnostic tools that are currently available to the radiologist. The rationale for pursuing electromagnetic methods is strong given the data in the literature, which show that the electromagnetic properties of breast malignancy are significantly different than normal in the high megahertz to low gigahertz spectral range, microwave illumination can effectively penetrate the breast at these frequencies, and the breast is a small readily accessible tissue volume, making it an ideal site for deploying advanced near-field imaging concepts that exploit model-based image reconstruction methodology. In this paper a clinical prototype of a microwave imaging system, which actively illuminates the breast with a 16-element transceiving monopole antenna array in the 300-1000 MHz range, is reported. Microwave exams have been delivered to five women through a water-coupled interface to the pendant breast with the participant positioned prone on an examination table. This configuration has been found to be a practical, comfortable approach to microwave breast imaging. Sessions lasted 10-15 min per breast and included full tomographic data acquisition at seven different array heights beginning at the chest wall and moving anteriorly toward the nipple for seven different frequencies at each array position. This clinical experience appears to be the first report of active near-field microwave imaging of the breast and is certainly the first attempt to exploit model-based image reconstructions from in vivo breast data in order to convert the measured microwave signals into spatial maps of electrical permittivity and conductivity. While clearly preliminary, the results are encouraging and have supplied some interesting findings. Specifically, it appears that the average relative permittivity of the breast as a whole correlates with radiologic breast density categorization and may be considerably higher than previously published values, which have been based on ex vivo tissue specimens.

The current status of breast MR imaging. Part I. Choice of technique, image interpretation, diagnostic accuracy, and transfer to clinical practice.

Abstract: Compared with mammography and breast ultrasonography, contrast material–enhanced magnetic resonance (MR) imaging is a breast imaging technique that offers not only information on lesion cross-sectional morphology but also on functional lesion features such as tissue perfusion and enhancement kinetics. After an enthusiastic start to clinical breast MR imaging in the early 1990s, a variety of difficulties and obstacles were identified that hampered the transfer of the modality into clinical practice, including a lack of standardization regarding image acquisition and interpretation guidelines, a lack of MR-compatible interventional materials, and a lack of evidence regarding its diagnostic accuracy—particularly specificity and positive predictive value, as well as sensitivity for ductal carcinoma in situ. This article is the first of two on the current status of breast MR imaging. The pathophysiologic basis of breast MR and the effects on acquisition technique and diagnostic accuracy, the diverging demands ...