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Daniel B Kopans

Publications and source records attributed to Daniel B Kopans.

At least 19 recordsLinked to original sources
PubMed2006

Voting strategy for artifact reduction in digital breast tomosynthesis.

Artifacts are observed in digital breast tomosynthesis (DBT) reconstructions due to the small number of projections and the narrow angular range that are typically employed in tomosynthesis imaging. In this work, we investigate the reconstruction artifacts that are caused by high-attenuation features in breast and develop several artifact reduction methods based on a "voting strategy." The voting strategy identifies the projection(s) that would introduce artifacts to a voxel and rejects the projection(s) when reconstructing the voxel. Four approaches to the voting strategy were compared, including projection segmentation, maximum contribution deduction, one-step classification, and iterative classification. The projection segmentation method, based on segmentation of high-attenuation features from the projections, effectively reduces artifacts caused by metal and large calcifications that can be reliably detected and segmented from projections. The other three methods are based on the observation that contributions from artifact-inducing projections have higher value than those from normal projections. These methods attempt to identify the projection(s) that would cause artifacts by comparing contributions from different projections. Among the three methods, the iterative classification method provides the best artifact reduction; however, it can generate many false positive classifications that degrade the image quality. The maximum contribution deduction method and one-step classification method both reduce artifacts well from small calcifications, although the performance of artifact reduction is slightly better with the one-step classification. The combination of one-step classification and projection segmentation removes artifacts from both large and small calcifications.

Algorithms↗
PubMed2006

Long-term risk of false-positive screening results and subsequent biopsy as a function of mammography use.

PURPOSE: To retrospectively determine the long-term risk of false-positive mammographic assessments and to evaluate the effect of screening regularity on the risk of false-positive events. MATERIALS AND METHODS: Institutional review board approval was obtained, and informed consent was waived. Retrospective analysis was performed for the occurrence of false-positive assessments among 83,511 women who underwent 314,185 mammographic examinations from January 1, 1985, to February 19, 2002. Data were collected from a database that had been assembled prospectively. Two categories of false-positive events were examined: biopsies that did not reveal cancer and false-positive mammographic assessments. Rates of false-positive events were compared by using a chi2 analysis, and 95% confidence limits were calculated. Because comparisons of multiple pairs were considered, all P values that demonstrated statistical significance exceeded the requirement of the Bonferroni correction. RESULTS: While the overall rates of biopsies that did not reveal cancer and of false-positive mammographic assessments were similar to those found in other studies, most of the burden of false-positive events was borne by women who underwent intermittent screening. Long-term rates of false-positive events were lower among women who underwent regular screening than among those who underwent intermittent screening. In the 5-year group, 2.9% of women who underwent five mammographic examinations over the next 5 years had biopsy results that did not reveal cancer, whereas 4.6% of women who underwent three mammographic examinations over the next 5 years had biopsy results that did not reveal cancer. For women who underwent regular screening, the risk of undergoing biopsies that did not reveal cancer declined over time to 0.25% per year after several years of screening, a value that is lower than the risk of these events among women who did not undergo screening. The rate of false-positive mammographic assessments was also lower for women who underwent regular screening than for those who underwent intermittent screening. CONCLUSION: Prompt annual attendance for mammographic screening reduces the occurrence of false-positive mammographic results.

Adult↗
PubMed2005

Prevalence of hereditary breast/ovarian carcinoma risk in patients with a personal history of breast or ovarian carcinoma in a mammography population.

BACKGROUND: Identifying BRCA1 and BRCA2 mutation carriers is increasingly important as new management options show promise in decreasing morbidity and mortality in these women. The authors sought to determine the prevalence of family histories suggestive of a hereditary breast carcinoma syndrome in a cohort of patients with a personal history of breast and/or ovarian carcinoma presenting for mammography. METHODS: The authors reviewed the family histories of all women with a history of breast or ovarian carcinoma presenting for mammography over a 37-week period. Using the Myriad model, the authors evaluated the prevalence of family histories with a > or = 10% risk of a BRCA1 or BRCA2 mutation. RESULTS: During the period of the current study, 14,597 women completed a family history questionnaire. Of these women, 1764 had a personal history of breast or ovarian carcinoma, 86.6% had unilateral breast carcinoma, 4.6% had bilateral breast carcinoma, 8.2% had ovarian carcinoma, and 0.5% had both breast and ovarian carcinoma. Overall, 20.6% met the criteria for a > or = 10% risk of mutation according to the Myriad model. This incidence was higher among Ashkenazi women (47.3%) and among patients with a personal history of ovarian carcinoma (35.9%). CONCLUSIONS: Application of the Myriad model to women with a personal history of breast and ovarian carcinoma suggested that approximately 1 in 5 of these women (20.6%) will have family histories suspicious for a genetic mutation. This risk was higher for Ashkenazi women and for those with a personal history of ovarian carcinoma. This prevalence was considerably higher than the rate reported among women with no personal history of cancer, and has significant implications for their management, as well as for the capacity for risk assessment and testing.

Breast Neoplasms↗
PubMed2005

Computer-aided detection system for breast masses on digital tomosynthesis mammograms: preliminary experience.

The purpose of the study was to design a computer-aided detection (CAD) system for breast mass detection on digital breast tomosynthesis (DBT) mammograms and to perform a preliminary evaluation of the performance of this system. Twenty-six patients were imaged with a prototype DBT system. Institutional review board approval and written informed patient consent were obtained. Use of the data set in this study was HIPAA compliant. The CAD system first screened the three-dimensional volume of the mass candidates by means of gradient-field analysis. Each mass candidate was segmented from the structured background, and its image features were extracted. A feature classifier was designed to differentiate true masses from normal tissues. The CAD system was trained and tested by using a leave-one-case-out method. The classifier calculated a mean area under the test receiver operating characteristic curve of 0.91 +/- 0.03 (standard error of mean). The CAD system achieved a sensitivity of 85%, with 2.2 false-positive objects per case. The results demonstrate the feasibility of the authors' approach to the development of a CAD system for DBT mammography.

Adult↗
PubMed2005

Hormone replacement therapy in postmenopausal women: breast tissue perfusion determined with MR imaging--initial observations.

PURPOSE: To use magnetic resonance (MR) imaging to evaluate tissue perfusion in the normal breast parenchyma of postmenopausal women with current or recent hormone replacement therapy (HRT). MATERIALS AND METHODS: The study was approved by the institutional subcommittee on human studies, and informed consent was obtained from all patients prior to MR imaging. Sixty postmenopausal women (age range, 44-77 years) were grouped according to HRT received: estrogen replacement therapy (ERT) (n = 13), combined (estrogen and progesterone) replacement therapy (CRT) (n = 16), selective estrogen receptor modulator (SERM) therapy (n = 8), and no (hormone replacement) therapy (NT) (n = 23). MR imaging with a 1.5-T magnet was performed by using gradient-echo and dynamic contrast material-enhanced echo-planar pulse sequences before and after gadopentetate dimeglumine injection. Precontrast T1 relaxation times were measured, after which extraction-flow product (EFP) maps were calculated with a multicompartmental model. Analysis of variance was performed. RESULTS: Age did not significantly differ between the groups (P > .3). Women receiving ERT or CRT at the time of MR imaging had higher EFP values (7.3 mL . 100 g(-1) . min(-1)+/- 2.6 and 7.1 mL . 100 g(-1) . min(-1)+/- 3.8, respectively) than did women receiving NT (4.4 mL . 100 g(-1) . min(-1)+/- 2.1) (P = .012 and P = .008, respectively) or SERM therapy (3.9 mL . 100 g(-1) . min(-1)+/- 1.1) (P = .015 and P = .013, respectively). Women who ended ERT or CRT 1-47 months before MR examination had lower EFP values than did women with current ERT or CRT and had higher EFP values than did women receiving NT or SERM therapy (6.2 mL . 100 g(-1) . min(-1)+/- 2.4 and 5.9 mL . 100 g(-1) . min(-1)+/- 3.8, respectively), but the observed differences were not significant (P > .1). Differences in T1 between all groups were not significant (P > .5). CONCLUSION: Higher breast tissue perfusion is observed in postmenopausal women receiving HRT.

Adult↗
PubMed2005

Radiological reasoning: male breast mass with calcifications.

OBJECTIVE: We encountered a mammographically calcified breast mass in a 30-year-old man. It was initially thought to be comedo-type ductal carcinoma in situ because of the dense calcifications, but sonography and MRI suggested a highly vascular lesion. The final pathologic diagnosis was hemangioma. CONCLUSION: Vascular tumors of the breast occur infrequently and are even more rare in males. The clinical and radiologic diagnosis of breast hemangioma is often difficult, but different imaging techniques, when used together, can provide important information for differential diagnosis and management. A biopsy is required.

Adult↗
PubMed2005

Prospective comparison of mammography, sonography, and MRI in patients undergoing neoadjuvant chemotherapy for palpable breast cancer.

OBJECTIVE: The objective of our study was to determine the relative accuracy of mammography, sonography, and MRI in predicting residual tumor after neoadjuvant chemotherapy for breast cancer as compared with the gold standards of physical examination and pathology. SUBJECTS AND METHODS: Forty-one women with stage IIB-III palpable breast cancer were prospectively enrolled in a study investigating the effects of sequential single-agent chemotherapy (doxorubicin followed by paclitaxel or vice versa) on tumor imaging. The study cohort consisted of the first 31 patients (age range, 31-65 years; mean, 45 years) who completed the protocol. All underwent physical examination, mammography, sonography, and MRI before and after receiving each neoadjuvant chemotherapeutic drug. Imaging studies were reviewed by two radiologists using conventional lexicons for lesion analysis, and the findings were compared with clinical response and pathology results. RESULTS: Complete, partial, and stable clinical response as defined by clinical examination was seen in 15, 14, and two of the 31 patients, respectively. Agreement rates about the degree of response were 32%, 48%, and 55%, respectively, for mammography, sonography, and MRI compared with clinical evaluation and did not differ statistically. Agreement about the rate of response as measured by clinical examination, mammography, sonography, and MRI compared with the gold standard (pathology) was 19%, 26%, 35%, and 71%, respectively. Of the four, MRI agreed with the gold standard significantly more often (p < 0.002 for all three paired comparisons with MRI). When there was disagreement with the gold standard, none of the four exhibited a significant tendency to either under- or overestimate. CONCLUSION: MRI appears to provide the best correlation with pathology-better than physical examination, mammography, and sonography-in patients undergoing neoadjuvant chemotherapy. However, MRI may overestimate (6%) or underestimate (23%) residual disease in approximately 29% of the patients (95% confidence interval, 14-48%).

Adult↗
PubMed2005

Bias in the medical journals: a commentary.

Most readers are not aware of the fact that medical journals may have an unspoken bias in the papers that they select for publication. These biases can have far-reaching consequences. The controversy over mammography screening for women ages 40-49 is a case in point. Several medical journals knowingly have refused to provide women with accurate information. Consequently, women have been led to believe that the age of 50 has some real significance with regard to screening when the fact is that it has none.

Adult↗
PubMed2005

Evaluation of hereditary risk in a mammography population.

PURPOSE: BRCA1 and BRCA2 mutations significantly increase a women's lifetime risk of breast and ovarian cancer. Because several management options have shown promise in decreasing morbidity and mortality for these women, identifying potential mutation carriers is increasingly important. We have developed a large-scale method to collect family histories in a population of unaffected women presenting for mammography. We then applied current risk-assessment models to determine the prevalence of women at risk for hereditary breast and ovarian cancer. MATERIALS AND METHODS: We performed a retrospective review of family histories using data collected on all unaffected women presenting for mammography over a 14-week period. The Claus, Myriad II, and Hartmann models for hereditary risk assessment were applied to the survey results. RESULTS: The questionnaire was completed by 5736 women, 695 of whom were excluded because of a personal history of breast or ovarian cancer. Family histories of the remaining 5041 women were evaluated. Totals of 5.9%, 5.2%, and 3.3% of patients, respectively, met criteria for increased risk according to the Hartmann, Myriad II, and Claus models, corresponding to 3.5, 3.1, and 1.9 patients per day. Although 9.2% of patients met criteria for >/=1 model, only 1.4% met criteria for all 3. CONCLUSIONS: Application of available models to a screening population classifies a larger than expected number of women at high risk for a BRCA1 or BRCA2 mutation. New approaches to risk assessment and counseling are needed to apply our knowledge of hereditary risk to a broad population in a practical manner.

Adult↗
PubMed2005

Informed decision making: age of 50 is arbitrary and has no demonstrated influence on breast cancer screening in women.

OBJECTIVE. The article discusses the fact that for more than 20 years, there has been controversy concerning whether there is a benefit from mammographic screening for women ages 40-49. Based on a decision made many years ago to try to determine how menopause might influence the value of screening, the age of 50 was chosen as a surrogate for menopause. Despite the fact that there are no data to support this age as having any biologic relevance, it continues to be used as if the parameters and benefits of screening change abruptly at the age of 50. CONCLUSION. The data clearly show that the age of 50 is nothing more than an arbitrary age, and it is far from clear whether menopause has any important effect on screening. The "harms" of screening have been cited as reasons for not recommending screening before the age of 50, but since the ratio of harm to benefit changes steadily with increasing age, there is no legitimate rationale for this determination. Women and their physicians should be informed that the age of 50 is an arbitrary threshold in terms of mammography screening so that they can make informed decisions about their own health care.

Adult↗
PubMed2004

The age at which women begin mammographic screening.

BACKGROUND: The American Cancer Society recommends yearly mammographic screening for women starting at the age of 40 years. The authors examined the age at which women began screening at a large tertiary care center. METHODS: Utilization of mammography was assessed in a population of 72,417 women who received 254,818 screening mammograms at the Massachusetts General Hospital Avon Comprehensive Breast Center from January 1, 1985 to February 19, 2002, of which 940 received their first mammogram between January 16, 2000 and February 19, 2002. RESULTS: The median age at first mammogram for women in the population as a whole was 40.4 years. Sixty percent of women had their first mammogram by the end of their 40th year, and almost 90% had begun screening by age 50 years. However, these reassuring findings were not seen in several specific subpopulations of women. Black women began screening at a median age of 41.0 years, 0.7 years later than white women. Hispanic women began screening at a median age of 41.4 years, 1.1 years later than non-Hispanic women. Obese women began screening at a median age of 41.2 years, 1.6 years later than thin women. Women without a primary care physician began screening at a median age of 42.1 years, 1.8 years later than women with a primary care physician. Women without private health insurance began screening at a median age of 46.6 years, 6.3 years later than women with private health coverage. Women who did not speak English began screening at a median age of 49.3 years, 9.0 years later than women for whom English was the primary language. Women who both lacked private health insurance and spoke a language other than English began screening at a median age of 55.3 years, 15.2 years later than women without these characteristics. CONCLUSIONS: The analysis presented in the current study provided one of the most detailed descriptions of the age at screening initiation to be performed to date. Most women in the study population began screening by the end of their 40th year. This contrasted with the widespread failure of women to return promptly for subsequent annual examinations. However, specific subpopulations of women were at risk for not beginning screening on time, including women without private insurance, women without a primary care physician, and women who did not speak English. These findings suggest that there is little to be gained from populationwide efforts to encourage entry into the screening process, and that public health efforts should be focused on those subpopulations of women at highest risk for not using screening. These results also indicate that public health efforts to encourage women to start screening may be less critical than interventions to improve prompt return once they have entered the screening system.

Adult↗
PubMed2004

Mammographic screening: patterns of use and estimated impact on breast carcinoma survival.

BACKGROUND: Although many studies support the life-saving potential of screening mammography, the actual utilization of screening and the impact of the actual pattern of screening use on the breast carcinoma death rate, remain incompletely understood. In the current report, the authors describe patterns of screening use among women who were examined at a large screening and diagnostic service and estimate the added mortality associated with missed screening mammograms. METHODS: Mammography use was assessed in a population of 72,417 women who received a total of 254,818 screening mammograms at the Massachusetts General Hospital (MGH) Avon Comprehensive Breast Center (Boston, MA) between January 1, 1985, and February 19, 2002. A computer simulation of breast carcinoma growth, spread, and detection of breast carcinoma was used to estimate the likely health consequences of various types of screening use. RESULTS: Both prompt return for annual screening and full use of screening over extended periods of time were rare, and comparison of the MGH population with other populations revealed that the low level of use observed in the MGH population was not atypical. Only 6% of women who received a mammogram in 1992 received all annual mammograms that were available over the next 10 years; the mean number of mammograms received during this period was 5.06, or 51% of the number recommended by the American Cancer Society. Computer simulation results indicate that this underutilization of screening should result in higher mortality levels. Women from traditionally underserved socioeconomic, racial, and ethnic groups, women without insurance, and women who did not speak English had lower levels of use compared with other women. Lower levels of use also were observed among women receiving their first mammogram or who in the past had not returned promptly. Women ages 55-65 years had higher levels of use than did younger or older women. Women who previously had breast carcinoma also had higher levels of screening use. Nonetheless, none of the subpopulations of women stratified by age, race, ethnicity, zip code, income,language, insurance, status, previous screening use, or medical history exhibited a widespread propensity to promptly return for annual screening over an extended period of time. CONCLUSIONS: By many measures, the current analysis is one of the most detailed descriptions of screening use to date. The authors observed a level of screening use that was disappointingly low, with potentially negative health-related consequences, among women across categories defined by racial, ethnic, socioeconomic, and geographic characteristics; insurance status; language; age; medical history; and previous screening use. Improvements in the promptness with which women return to screening appear to have the potential to lead to considerable reductions in breast carcinoma death.

Adult↗