Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MAMMOGRAPHY”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,801 records · Page 100Linked to original sources
PubMed2002

Improving the accuracy of mammography: volume and outcome relationships.

BACKGROUND: Countries with centralized, high-volume mammography screening programs, such as the U.K. and Sweden, emphasize high specificity (low percentage of false positives) and high sensitivity (high percentage of true positives). By contrast, the United States does not have centralized, high-volume screening programs, emphasizes high sensitivity, and has lower average specificity. We investigated whether high sensitivity can be achieved in the context of high specificity and whether the number of mammograms read per radiologist (reader volume) drives both sensitivity and specificity. METHODS: The U.K.'s National Health Service Breast Screening Programme uses the PERFORMS 2 test as a teaching and assessment tool for radiologists. The same 60-film PERFORMS 2 test was given to 194 high-volume U.K. radiologists and to 60 U.S. radiologists, who were assigned to low-, medium-, or high-volume groups on the basis of the number of mammograms read per month. The standard binormal receiver-operating characteristic (ROC) model was fitted to the data of individual readers. Detection accuracy was measured by the sensitivity at specificity = 0.90, and differences among sensitivities were determined by analysis of variance. RESULTS: The average sensitivity at specificity = 0.90 was 0.785 for U.K. radiologists, 0.756 for high-volume U.S. radiologists, 0.702 for medium-volume U.S. radiologists, and 0.648 for low-volume U.S. radiologists. At this specificity, low-volume U.S. radiologists had statistically significantly lower sensitivity than either high-volume U.S. radiologists or U.K. radiologists, and medium-volume U.S. radiologists had statistically significantly lower sensitivity than U.K. radiologists (P<.001, for all comparisons). CONCLUSIONS: Reader volume is an important determinant of mammogram sensitivity and specificity. High sensitivity (high cancer detection rate) can be achieved with high specificity (low false-positive rate) in high-volume centers. This study suggests that there is great potential for optimizing mammography screening.

Breast Neoplasms↗
PubMed2003

International variation in screening mammography interpretations in community-based programs.

BACKGROUND: Variations in mammography interpretations may have important clinical and economic implications. To evaluate international variability in mammography interpretation, we analyzed published reports from community-based screening programs from around the world. METHODS: A total of 32 publications were identified in MEDLINE that fit the study inclusion criteria. Data abstracted from the publications included features of the population screened, examination technique, and clinical outcomes, including the percentage of mammograms judged to be abnormal, positive predictive value of an abnormal mammogram (PPV(A)), positive predictive value of a biopsy performed (PPV(B)), and percentages of breast cancer patients with ductal carcinoma in situ (DCIS) and minimal disease (DCIS and/or tumor size < or =10 mm). North American screening programs were compared with those from other countries using meta-regression analysis. All statistical tests were two-sided. RESULTS: Wide ranges were noted for the percentage of mammograms judged to be abnormal (1.2%-15.0%), for PPV(A) (3.4%-48.7%), for PPV(B) (5.0%-85.2%), for percentage diagnosed with DCIS (4.3%-68.1%), and for percentage diagnosed with minimal disease (14.0%-80.6%). The percentage of mammograms judged to be abnormal were 2-4 percentage points higher in North American screening programs than they were in programs from other countries, after adjusting for covariates such as percentage of women who were less than 50 years of age and calendar year in which the mammogram was performed. The percentage of mammograms judged to be abnormal had a negative association with PPV(A) and PPV(B) (both P<.001) and a positive association with the frequency of DCIS cases diagnosed (P =.008) and the number of DCIS cases diagnosed per 1000 screens (P =.024); no consistent relationship was observed with the proportion of breast cancer diagnoses reported as having minimal disease or the number of minimal disease cases diagnosed per 1000 screens. CONCLUSION: North American screening programs appear to interpret a higher percentage of mammograms as abnormal than programs from other countries without evident benefit in the yield of cancers detected per 1000 screens, although an increase in DCIS detection was noted.

Aged↗
PubMed2004

Accuracy of screening mammography interpretation by characteristics of radiologists.

BACKGROUND: Radiologists differ in their ability to interpret screening mammograms accurately. We investigated the relationship of radiologist characteristics to actual performance from 1996 to 2001. METHODS: Screening mammograms (n = 469,512) interpreted by 124 radiologists were linked to cancer outcome data. The radiologists completed a survey that included questions on demographics, malpractice concerns, years of experience interpreting mammograms, and the number of mammograms read annually. We used receiver operating characteristics (ROC) analysis to analyze variables associated with sensitivity, specificity, and the combination of the two, adjusting for patient variables that affect performance. All P values are two-sided. RESULTS: Within 1 year of the mammogram, 2402 breast cancers were identified. Relative to low annual interpretive volume (< or =1000 mammograms), greater interpretive volume was associated with higher sensitivity (P = .001; odds ratio [OR] for moderate volume [1001-2000] = 1.68, 95% CI = 1.18 to 2.39; OR for high volume [>2000] = 1.89, 95% CI = 1.36 to 2.63). Specificity decreased with volume (OR for 1001-2000 = 0.65, 95% CI = 0.52 to 0.83; OR for more than 2000 = 0.76, 95% CI = 0.60 to 0.96), compared with 1000 or less (P = .002). Greater number of years of experience interpreting mammograms was associated with lower sensitivity (P = .001), but higher specificity (P = .003). ROC analysis using the ordinal BI-RADS interpretation showed an association between accuracy and both previous mammographic history (P = .012) and breast density (P<.001). No association was observed between accuracy and years interpreting mammograms (P = .34) or mammography volume (P = .94), after adjusting for variables that affect the threshold for calling a mammogram positive. CONCLUSIONS: We found no evidence that greater volume or experience at interpreting mammograms is associated with better performance. However, they may affect sensitivity and specificity, possibly by determining the threshold for calling a mammogram positive. Increasing volume requirements is unlikely to improve overall mammography performance.

Adult↗
PubMed1997

Nonpalpable breast cancer in women aged 40-49 years: a surgeon's view of benefits from screening mammography.

While mammography screening among women aged 50 years or older has proven to reduce breast cancer mortality, screening in younger women has been repeatedly scrutinized. To test the effect of screening among younger women, we examined 84 consecutive patients aged 40-49 at the time of breast cancer diagnosis: 27 (32.1%) were diagnosed solely by mammography, and 57 (67.9%) had a palpable mass. The mean tumor sizes were 1.3 cm and 3.6 cm for the two groups respectively. While 68.8% nonpalpable invasive tumors were classified as Stage I cancer, only 34% of patients with palpable breast cancer had Stage I disease. None of the patients with nonpalpable breast cancer had disease beyond Stage II. In contrast, 28.3% of the patients with palpable invasive breast cancer presented with advanced disease. In addition, 6.3% versus 41.5% of patients with nonpalpable and palpable breast cancer respectively had nodal metastases. The five-year survival rates for the two groups were 100% and 73% respectively, favoring breast cancer detected mammographically. Screening of women aged 40-49 also resulted in more breast-conserving surgery and less chemotherapy. We conclude that screening in this age group should be continued, although individual assessment is needed.

Adult↗
PubMed1997

Increases in ductal carcinoma in situ (DCIS) of the breast in relation to mammography: a dilemma.

The increased use of screening mammography has resulted in a marked increase in detected cases of ductal carcinoma in situ (DCIS) of the breast since the early 1980s. In 1993, there were an estimated 23,275 newly diagnosed cases of DCIS in the United States, of which 4,676 were in women aged 40-49. DCIS accounted for 14.7% of all newly diagnosed breast cancers in women aged 40-49 in 1993, and perhaps 40% of all mammographically detected breast cancers in this age group are DCIS. Among women aged 40-49, an estimated 1,890 mastectomies and 2,707 lumpectomies (with or without radiation) were performed for DCIS in 1993. There is an urgent need to better understand the relationship of mammographically detected DCIS to invasive and potentially life-threatening breast cancer. Better information about the appropriate treatment of DCIS is also needed to reduce the confusion and uncertainty many women and their physicians currently experience in the face of a DCIS diagnosis. For the present, women considering screening mammography should be told the likelihood of being diagnosed with DCIS and that only some DCIS cases may be clinically significant but almost all will be treated surgically.

Adult↗
PubMed1997

Updated overview of the Swedish Randomized Trials on Breast Cancer Screening with Mammography: age group 40-49 at randomization.

The purpose of this overview is to estimate more precisely the long-term effect of mammography screening by adding four more years of follow-up to women aged 40-49 years in the four Swedish trials on mammography screening. Data from the four, trials were merged and linked to the Swedish Cancer and Cause of Death Register for 1958-1993 and 1951-1993 respectively to identify date of breast cancer diagnosis and cause and date of death. The invited and control groups comprised 48,569 and 40,247 women respectively. At the December 1993 follow-up, 602 and 482 breast cancer cases were identified in the two groups respectively, of which 104 and 111 had breast cancer as the underlying cause of death. This corresponds to a relative risk (RR) of 0.77 (95% CI: 0.59-1.01) for the two groups. In the 40-44 age group at randomization, 94% of breast cancer patients in the study and 89% in the control group were diagnosed before the age of 50; however, among breast cancer deaths in this age group, only two in the invited and five in the control group died after age 50. At follow-up of women 40-44 years at randomization 208 women in the invited and 184 in the control group were reported to the Cancer registry with breast cancer. Out of these 195 (94%) and 163 (89%) respectively were reported before the age of 50. Further, the relative risk for the age group 40-44 years at randomization by age at follow-up was 1.11, 0.51 and 0.46 for the age groups 45-49, 50-54, and 55-59 at follow-up. This study shows a 23% reduction in the breast cancer mortality in women 40-49 years at randomization achieved from a median trial time of 7.0 years, a median follow-up time of 12.8 years, and a screening interval of 18-24 months. Almost all of the effect in the 40-44 year age group at randomization was due to screening before the age of 50.

Adult↗
PubMed1997

Breast cancer screening outcomes in women ages 40-49: clinical experience with service screening using modern mammography.

The several randomized controlled trials (RCTs) of breast cancer screening among women of ages 40 to 49 now collectively show a statistically significant reduction in breast cancer mortality. However, there have been numerous recent advances in mammography, such that it now is demonstrably better than when the RCTs were conducted. The use of surrogate measures of screening efficacy (tumor size, lymph node status, cancer stage), readily derived from modern service screening programs, demonstrates how the improved mammography of the 1990s should produce a greater degree of mortality reduction among women ages 40-49 than that already demonstrated in the RCTs. Indeed, these surrogate measures of mortality reduction are as favorable for women of ages 40-49 and 65+ as they are for women of ages 50-64, strongly suggesting that, since modern service screening is accepted as effectively reducing mortality among women of ages 50-64, it should also effectively reduce mortality among women in the 40-49 and 65+ age groups.

Adult↗
PubMed2006

Impact of adjuvant therapy and mammography on U.S. mortality from 1975 to 2000: comparison of mortality results from the cisnet breast cancer base case analysis.

The CISNET breast cancer program is a consortium of seven research groups modeling the impact of various cancer interventions on the national trends of breast cancer incidence and mortality. Each of the modeling groups participated in a CISNET breast cancer base case analysis with the objective of assessing the impact of mammography and adjuvant therapy on breast cancer mortality between 1975 and 2000. The comparative modeling approach used to address this question allowed for a unique view into the process of modeling. Results shown here expand on those recently reported in the New England Journal of Medicine (Berry et al., N Engl J Med 2005;353:1784-92) by presenting mortality impact in several different ways to facilitate comparisons between models. Comparisons of each group's results in the context of modeling assumptions made during the process gave insight into how specific model assumptions may have affected the results. The median estimate for the percent decline in breast cancer mortality due to mammography was 15% (range of 8%-23%), and the median estimate for the percent decline in mortality due to adjuvant treatment was 19% (range of 12%-21%). A detailed discussion of the differences in modeling approaches and how those differences may have influenced the mortality results concludes the chapter.

Adult↗
PubMed2002

Breast dose variability in a bi-racial population undergoing screening mammography.

This study evaluated individual and population dose variability during screening mammography, among 570 white and black women in South Carolina, USA. Aspects of dosimetry that were considered include compressed breast thickness (CBT), number of films per screening session, and dose in previous or subsequent sessions. Breast dose was log-normally distributed in the population, with a geometric mean of 6.6 mGy per session. Doses were significantly higher for black women, for women with high CBT or who receive more than two views per breast, and for the mediolateral oblique, compared to the craniocaudal, view. No relationship was observed between age and dose. Total dose per breast varied by a factor of 20 across the study population, but the individual's dose varied little among repeat screening sessions, especially after adjusting for the number of films received per session. These results may inform assessments of the projected risks of inducing breast cancer from screening mammography.

Adult↗
PubMed2002

Microdosimetric characterisation of 28 kVp Mo/Mo, Rh/Rh, Rh/Al, W/Rh and Mo/Rh mammography X ray spectra.

Microdosimetric characteristics of 28 kVp mammography X ray spectra were studied for several target/added filtration combinations (Mo/Mo, Rh/Rh, Rh/Al, W/Rh, Mo/Rh). Monte Carlo techniques were used to model X ray production from mammography units and to calculate distributions of absorbed dose and energy imparted in breast tissue. The results show that the dose averaged lineal energy is about 5.0 keV.micron-1, about 25% higher than for general diagnostic imaging X ray spectra. Significant differences in lineal energy between the five X ray qualities were noted, with the highest value for the commonly used Mo/Mo combination. Spectral hardening with depth in the tissues causes a 5% decrease in lineal energy over 5 cm. No significant differences were found for the different tissue compositions.

Breast↗
PubMed2005

A survey of patient dose and clinical factors in a full-field digital mammography system.

In this work, we analyse the dose to 5034 patients (20 137 images) who underwent mammographic examinations with a full-field digital mammography (FFDM) system over a 2-y period. The information relevant to this study has been extracted from the image Digital Imaging and Communications in Medicine (DICOM) headers. Entrance surface air-kerma (ESAK) without backscatter and average glandular dose (AGD) were estimated following the methodology proposed in the European Protocol on Dosimetry in Mammography. Mean values for patient age and compressed breast thickness were 56 +/- 11 y and 52 +/- 13 mm, respectively. The mean ESAK value was 8.1 mGy and the mean AGD was 1.9 mGy. In addition, the dose values from both FFDM and screening-film mammographic (SFM) examinations were compared. The third quartile (TQ) of the ESAK values delivered by the FFDM system was 33% lower and 32% higher than the TQ for SFM with slow and fast screen/film receptors. Differences between dose values for cranio-caudal (CC) and medio-lateral oblique (MLO) images (about 27% for SFM) decreased to 11% for FFDM.

Adolescent↗
PubMed2005

Using simple mathematical functions to simulate pathological structures--input for digital mammography clinical trial.

In this study a set of structures has been simulated to represent a range of clinically relevant breast cancer mammographic lesions including solid tumours and microcalcifications. All structures have been created using simple random-based mathematical functions and have been inserted into a subset of digital mammography images at appropriate contrast levels into various regions of the breast, including dense fibroglandular and adipose tissue. These structures and their appearance in these clinical images were evaluated in terms of how realistic they looked. They will be used as the input to a large-scale clinical trial designed to examine the effect of significant dose reduction in digital mammography by comparing the detectability of such structures in images acquired at full and quarter automatic exposure control (AEC) dose level and in images with simulated noise levels in between.

Adipose Tissue↗
PubMed2005

Clinical evaluation of a new set of image quality criteria for mammography.

The European Commission (EC) quality criteria for screen-film mammography are used as a tool to assess image quality. A new set of criteria was developed and initially tested in a previous study. In the present study, these criteria are further evaluated using screen-film mammograms that have been digitised, manipulated to simulate different image quality levels and reprinted on film. Expert radiologists have evaluated these manipulated images using both the original (EC) and the new criteria. A comparison of three different simulated dose levels reveals that the new criteria yield a larger separation of image criteria scores than the old ones. These results indicate that the new set of image quality criteria has a higher discriminative power than the old set and thus seems to be more suitable for evaluation of image quality in mammography.

Europe↗
PubMed2005

Evaluation of patient dose for mammography in Pernambuco, Brazil.

The aim of this study is to evaluate the incident air kerma (INAK) and the mean glandular dose (MGD) during mammography in Recife, North-east Brazil. The study was performed in three institutions: a private clinic (A), a public hospital (B) and a private hospital (C). The incident air kerma to mammography procedures were estimated using a standard breast phantom and the patient MGD, evaluated in the units B and C, was performed using the calibration of output method. This method involves the recording of the patient exposure parameters (kVp, mAs, filter) and the measurement of these parameters of the incident air kerma using a calibrated ionisation chamber. The results obtained showed that INAK for the standard breast phantom, in the institutions A, B and C, were 18.2, 9.4 and 8.5 mGy, respectively. The results of patient MGD values ranged from 0.23 to 7.46 mGy per film, and the MGD values per woman were between 8.23 and 40.6 mGy for the C institution and between 1.50 and 18.78 mGy for the B institution.

Body Burden↗
PubMed2005

The performance of commercial photodiodes for dosimetry in mammography.

This paper reports the results of an investigation carried out to determine the suitability of using a commercially available photodiode for dosimetry in mammography thereby providing a low cost dosemeter with a direct reading of the radiation dose. A mammographic X-ray generator (Siemens Mammomat 1000) with tube potential in the 23-30 kV range and a constant potential X-ray generator (Pantak) with a W/Mo anode/filter combination were used in this study. The results showed that the photodiode response is highly linear within mammographic dose ranges and that the energy dependence was <3% at tube potentials of 25-30 kV. Good agreement was observed between the incident air kerma measured with both the photodiode and the ionization chamber. These results show the viability of using the photodiode as a dosemeter system in mammography.

Body Burden↗
PubMed2005

Assessment of mammography spectra using compton spectrometry techniques.

The quality control of mammography units is necessary to reduce the dose imparted to women as much as possible. An accurate characterisation of the primary X-ray spectra is very useful for this purpose. Primary spectra can be obtained using Compton spectrometry techniques. In this work, a commercial spectrometer used to characterise a mammography X-ray tube has been simulated using the Monte Carlo method by means of the MCNP code. Using the developed model, a Response matrix is obtained. Owing to the fact that this matrix is ill-conditioned, the inversion is not a simple process. This problem has been solved using the truncated singular value decomposition method. Results obtained when this methodology was applied have been compared with theoretical X-ray spectra.

Body Burden↗
PubMed2006

Neoplastic transformation of a human hybrid cell line by alpha particles in relation to mammography X rays.

The hybrid cell line CGL1 is the only cell line which allows quantitation of neoplastic transformation in human cells. Hybrid cells were exposed to 3.4 MeV alpha particles or to mammography X rays (29 kV(p)) and both survival and neoplastic cell transformation were assayed. For comparison, previously published data obtained with 200 kV(p) X rays are also included. Alpha particles were significantly more efficient than 29 kV(p) X rays in cell killing. Surprisingly, the efficiency of mammography X rays for the induction of neoplastic cell transformation was close to that observed for alpha particles.

Alpha Particles↗
PubMed1989

Ultrasound mammography in prosthesis-related breast augmentation complications.

Ultrasound mammography is presented as a safe, simple, and reliable method of assessing prosthesis and prosthesis-related complications in the augmented breast. The ability to distinguish between silicone gel, muscle, hematoma, and fluid collections has made ultrasound mammography especially valuable in diagnosing capsular rupture, implant rupture, or periprosthetic hematoma in subpectoral breast augmentations. Examples are given and discussed.

Adult↗

Refine your search to explore more results.