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Sample records for qualitative mammographic features

  1. Characterizing mammographic images by using generic texture features

    PubMed Central

    2012-01-01

    Introduction Although mammographic density is an established risk factor for breast cancer, its use is limited in clinical practice because of a lack of automated and standardized measurement methods. The aims of this study were to evaluate a variety of automated texture features in mammograms as risk factors for breast cancer and to compare them with the percentage mammographic density (PMD) by using a case-control study design. Methods A case-control study including 864 cases and 418 controls was analyzed automatically. Four hundred seventy features were explored as possible risk factors for breast cancer. These included statistical features, moment-based features, spectral-energy features, and form-based features. An elaborate variable selection process using logistic regression analyses was performed to identify those features that were associated with case-control status. In addition, PMD was assessed and included in the regression model. Results Of the 470 image-analysis features explored, 46 remained in the final logistic regression model. An area under the curve of 0.79, with an odds ratio per standard deviation change of 2.88 (95% CI, 2.28 to 3.65), was obtained with validation data. Adding the PMD did not improve the final model. Conclusions Using texture features to predict the risk of breast cancer appears feasible. PMD did not show any additional value in this study. With regard to the features assessed, most of the analysis tools appeared to reflect mammographic density, although some features did not correlate with PMD. It remains to be investigated in larger case-control studies whether these features can contribute to increased prediction accuracy. PMID:22490545

  2. Assessment of two mammographic density related features in predicting near-term breast cancer risk

    NASA Astrophysics Data System (ADS)

    Zheng, Bin; Sumkin, Jules H.; Zuley, Margarita L.; Wang, Xingwei; Klym, Amy H.; Gur, David

    2012-02-01

    In order to establish a personalized breast cancer screening program, it is important to develop risk models that have high discriminatory power in predicting the likelihood of a woman developing an imaging detectable breast cancer in near-term (e.g., <3 years after a negative examination in question). In epidemiology-based breast cancer risk models, mammographic density is considered the second highest breast cancer risk factor (second to woman's age). In this study we explored a new feature, namely bilateral mammographic density asymmetry, and investigated the feasibility of predicting near-term screening outcome. The database consisted of 343 negative examinations, of which 187 depicted cancers that were detected during the subsequent screening examination and 155 that remained negative. We computed the average pixel value of the segmented breast areas depicted on each cranio-caudal view of the initial negative examinations. We then computed the mean and difference mammographic density for paired bilateral images. Using woman's age, subjectively rated density (BIRADS), and computed mammographic density related features we compared classification performance in estimating the likelihood of detecting cancer during the subsequent examination using areas under the ROC curves (AUC). The AUCs were 0.63+/-0.03, 0.54+/-0.04, 0.57+/-0.03, 0.68+/-0.03 when using woman's age, BIRADS rating, computed mean density and difference in computed bilateral mammographic density, respectively. Performance increased to 0.62+/-0.03 and 0.72+/-0.03 when we fused mean and difference in density with woman's age. The results suggest that, in this study, bilateral mammographic tissue density is a significantly stronger (p<0.01) risk indicator than both woman's age and mean breast density.

  3. Decision trees and integrated features for computer aided mammographic screening

    SciTech Connect

    Kegelmeyer, W.P. Jr.; Groshong, B.; Allmen, M.; Woods, K.

    1997-02-01

    Breast cancer is a serious problem, which in the United States causes 43,000 deaths a year, eventually striking 1 in 9 women. Early detection is the only effective countermeasure, and mass mammography screening is the only reliable means for early detection. Mass screening has many shortcomings which could be addressed by a computer-aided mammographic screening system. Accordingly, we have applied the pattern recognition methods developed in earlier investigations of speculated lesions in mammograms to the detection of microcalcifications and circumscribed masses, generating new, more rigorous and uniform methods for the detection of both those signs. We have also improved the pattern recognition methods themselves, through the development of a new approach to combinations of multiple classifiers.

  4. Characterization of mammographic masses based on level set segmentation with new image features and patient information

    SciTech Connect

    Shi Jiazheng; Sahiner, Berkman; Chan Heangping; Ge Jun; Hadjiiski, Lubomir; Helvie, Mark A.; Nees, Alexis; Wu Yita; Wei Jun; Zhou Chuan; Zhang Yiheng; Cui Jing

    2008-01-15

    Computer-aided diagnosis (CAD) for characterization of mammographic masses as malignant or benign has the potential to assist radiologists in reducing the biopsy rate without increasing false negatives. The purpose of this study was to develop an automated method for mammographic mass segmentation and explore new image based features in combination with patient information in order to improve the performance of mass characterization. The authors' previous CAD system, which used the active contour segmentation, and morphological, textural, and spiculation features, has achieved promising results in mass characterization. The new CAD system is based on the level set method and includes two new types of image features related to the presence of microcalcifications with the mass and abruptness of the mass margin, and patient age. A linear discriminant analysis (LDA) classifier with stepwise feature selection was used to merge the extracted features into a classification score. The classification accuracy was evaluated using the area under the receiver operating characteristic curve. The authors' primary data set consisted of 427 biopsy-proven masses (200 malignant and 227 benign) in 909 regions of interest (ROIs) (451 malignant and 458 benign) from multiple mammographic views. Leave-one-case-out resampling was used for training and testing. The new CAD system based on the level set segmentation and the new mammographic feature space achieved a view-based A{sub z} value of 0.83{+-}0.01. The improvement compared to the previous CAD system was statistically significant (p=0.02). When patient age was included in the new CAD system, view-based and case-based A{sub z} values were 0.85{+-}0.01 and 0.87{+-}0.02, respectively. The study also demonstrated the consistency of the newly developed CAD system by evaluating the statistics of the weights of the LDA classifiers in leave-one-case-out classification. Finally, an independent test on the publicly available digital database

  5. Reduction of false-positive recalls using a computerized mammographic image feature analysis scheme

    NASA Astrophysics Data System (ADS)

    Tan, Maxine; Pu, Jiantao; Zheng, Bin

    2014-08-01

    The high false-positive recall rate is one of the major dilemmas that significantly reduce the efficacy of screening mammography, which harms a large fraction of women and increases healthcare cost. This study aims to investigate the feasibility of helping reduce false-positive recalls by developing a new computer-aided diagnosis (CAD) scheme based on the analysis of global mammographic texture and density features computed from four-view images. Our database includes full-field digital mammography (FFDM) images acquired from 1052 recalled women (669 positive for cancer and 383 benign). Each case has four images: two craniocaudal (CC) and two mediolateral oblique (MLO) views. Our CAD scheme first computed global texture features related to the mammographic density distribution on the segmented breast regions of four images. Second, the computed features were given to two artificial neural network (ANN) classifiers that were separately trained and tested in a ten-fold cross-validation scheme on CC and MLO view images, respectively. Finally, two ANN classification scores were combined using a new adaptive scoring fusion method that automatically determined the optimal weights to assign to both views. CAD performance was tested using the area under a receiver operating characteristic curve (AUC). The AUC = 0.793  ±  0.026 was obtained for this four-view CAD scheme, which was significantly higher at the 5% significance level than the AUCs achieved when using only CC (p = 0.025) or MLO (p = 0.0004) view images, respectively. This study demonstrates that a quantitative assessment of global mammographic image texture and density features could provide useful and/or supplementary information to classify between malignant and benign cases among the recalled cases, which may eventually help reduce the false-positive recall rate in screening mammography.

  6. Association of mammographic image feature change and an increasing risk trend of developing breast cancer: an assessment

    NASA Astrophysics Data System (ADS)

    Tan, Maxine; Leader, Joseph K.; Liu, Hong; Zheng, Bin

    2015-03-01

    We recently investigated a new mammographic image feature based risk factor to predict near-term breast cancer risk after a woman has a negative mammographic screening. We hypothesized that unlike the conventional epidemiology-based long-term (or lifetime) risk factors, the mammographic image feature based risk factor value will increase as the time lag between the negative and positive mammography screening decreases. The purpose of this study is to test this hypothesis. From a large and diverse full-field digital mammography (FFDM) image database with 1278 cases, we collected all available sequential FFDM examinations for each case including the "current" and 1 to 3 most recently "prior" examinations. All "prior" examinations were interpreted negative, and "current" ones were either malignant or recalled negative/benign. We computed 92 global mammographic texture and density based features, and included three clinical risk factors (woman's age, family history and subjective breast density BIRADS ratings). On this initial feature set, we applied a fast and accurate Sequential Forward Floating Selection (SFFS) feature selection algorithm to reduce feature dimensionality. The features computed on both mammographic views were individually/ separately trained using two artificial neural network (ANN) classifiers. The classification scores of the two ANNs were then merged with a sequential ANN. The results show that the maximum adjusted odds ratios were 5.59, 7.98, and 15.77 for using the 3rd, 2nd, and 1st "prior" FFDM examinations, respectively, which demonstrates a higher association of mammographic image feature change and an increasing risk trend of developing breast cancer in the near-term after a negative screening.

  7. Classification of mammographic masses: influence of regions used for feature extraction on the classification performance

    NASA Astrophysics Data System (ADS)

    Wagner, Florian; Wittenberg, Thomas; Elter, Matthias

    2010-03-01

    Computer-assisted diagnosis (CADx) for the characterization of mammographic masses as benign or malignant has a very high potential to help radiologists during the critical process of diagnostic decision making. By default, the characterization of mammographic masses is performed by extracting features from a region of interest (ROI) depicting the mass. To investigate the influence of the region on the classification performance, textural, morphological, frequency- as well as moment-based features are calculated in subregions of the ROI, which has been delineated manually by an expert. The investigated subregions are (a) the semi-automatically segmented area which includes only the core of the mass, (b) the outer border region of the mass, and (c) the combination of the outer and the inner border region, referred to as mass margin. To extract the border region and the margin of a mass an extended version of the rubber band straightening transform (RBST) was developed. Furthermore, the effectiveness of the features extracted from the RBST transformed border region and mass margin is compared to the effectiveness of the same features extracted from the untransformed regions. After the feature extraction process a preferably optimal feature subset is selected for each feature extractor. Classification is done using a k-NN classifier. The classification performance was evaluated using the area Az under the receiver operating characteristic curve. A publicly available mammography database was used as data set. Results showed that the manually drawn ROI lead to superior classification performances for the morphological feature extractors and that the transformed outer border region and the mass margin are not suitable for moment-based features but yield to promising results for textural and frequency-based features. Beyond that the mass margin, which combines the inner and the outer border region, leads to better classification performances compared to the outer border

  8. Feature and contrast enhancement of mammographic image based on multiscale analysis and morphology.

    PubMed

    Wu, Shibin; Yu, Shaode; Yang, Yuhan; Xie, Yaoqin

    2013-01-01

    A new algorithm for feature and contrast enhancement of mammographic images is proposed in this paper. The approach bases on multiscale transform and mathematical morphology. First of all, the Laplacian Gaussian pyramid operator is applied to transform the mammography into different scale subband images. In addition, the detail or high frequency subimages are equalized by contrast limited adaptive histogram equalization (CLAHE) and low-pass subimages are processed by mathematical morphology. Finally, the enhanced image of feature and contrast is reconstructed from the Laplacian Gaussian pyramid coefficients modified at one or more levels by contrast limited adaptive histogram equalization and mathematical morphology, respectively. The enhanced image is processed by global nonlinear operator. The experimental results show that the presented algorithm is effective for feature and contrast enhancement of mammogram. The performance evaluation of the proposed algorithm is measured by contrast evaluation criterion for image, signal-noise-ratio (SNR), and contrast improvement index (CII).

  9. Feature and Contrast Enhancement of Mammographic Image Based on Multiscale Analysis and Morphology

    PubMed Central

    Wu, Shibin; Xie, Yaoqin

    2013-01-01

    A new algorithm for feature and contrast enhancement of mammographic images is proposed in this paper. The approach bases on multiscale transform and mathematical morphology. First of all, the Laplacian Gaussian pyramid operator is applied to transform the mammography into different scale subband images. In addition, the detail or high frequency subimages are equalized by contrast limited adaptive histogram equalization (CLAHE) and low-pass subimages are processed by mathematical morphology. Finally, the enhanced image of feature and contrast is reconstructed from the Laplacian Gaussian pyramid coefficients modified at one or more levels by contrast limited adaptive histogram equalization and mathematical morphology, respectively. The enhanced image is processed by global nonlinear operator. The experimental results show that the presented algorithm is effective for feature and contrast enhancement of mammogram. The performance evaluation of the proposed algorithm is measured by contrast evaluation criterion for image, signal-noise-ratio (SNR), and contrast improvement index (CII). PMID:24416072

  10. A new and fast image feature selection method for developing an optimal mammographic mass detection scheme

    PubMed Central

    Tan, Maxine; Pu, Jiantao; Zheng, Bin

    2014-01-01

    Purpose: Selecting optimal features from a large image feature pool remains a major challenge in developing computer-aided detection (CAD) schemes of medical images. The objective of this study is to investigate a new approach to significantly improve efficacy of image feature selection and classifier optimization in developing a CAD scheme of mammographic masses. Methods: An image dataset including 1600 regions of interest (ROIs) in which 800 are positive (depicting malignant masses) and 800 are negative (depicting CAD-generated false positive regions) was used in this study. After segmentation of each suspicious lesion by a multilayer topographic region growth algorithm, 271 features were computed in different feature categories including shape, texture, contrast, isodensity, spiculation, local topological features, as well as the features related to the presence and location of fat and calcifications. Besides computing features from the original images, the authors also computed new texture features from the dilated lesion segments. In order to select optimal features from this initial feature pool and build a highly performing classifier, the authors examined and compared four feature selection methods to optimize an artificial neural network (ANN) based classifier, namely: (1) Phased Searching with NEAT in a Time-Scaled Framework, (2) A sequential floating forward selection (SFFS) method, (3) A genetic algorithm (GA), and (4) A sequential forward selection (SFS) method. Performances of the four approaches were assessed using a tenfold cross validation method. Results: Among these four methods, SFFS has highest efficacy, which takes 3%–5% of computational time as compared to GA approach, and yields the highest performance level with the area under a receiver operating characteristic curve (AUC) = 0.864 ± 0.034. The results also demonstrated that except using GA, including the new texture features computed from the dilated mass segments improved the AUC

  11. Optimal Breast Biopsy Decision-Making Based on Mammographic Features and Demographic Factors.

    PubMed

    Chhatwal, Jagpreet; Alagoz, Oguzhan; Burnside, Elizabeth S

    2010-11-01

    Breast cancer is the most common non-skin cancer affecting women in the United States, where every year more than 20 million mammograms are performed. Breast biopsy is commonly performed on the suspicious findings on mammograms to confirm the presence of cancer. Currently, 700,000 biopsies are performed annually in the U.S.; 55%-85% of these biopsies ultimately are found to be benign breast lesions, resulting in unnecessary treatments, patient anxiety, and expenditures. This paper addresses the decision problem faced by radiologists: When should a woman be sent for biopsy based on her mammographic features and demographic factors? This problem is formulated as a finite-horizon discrete-time Markov decision process. The optimal policy of our model shows that the decision to biopsy should take the age of patient into account; particularly, an older patient's risk threshold for biopsy should be higher than that of a younger patient. When applied to the clinical data, our model outperforms radiologists in the biopsy decision-making problem. This study also derives structural properties of the model, including sufficiency conditions that ensure the existence of a control-limit type policy and nondecreasing control-limits with age.

  12. Concordance of computer-extracted image features with BI-RADS descriptors for mammographic mass margin

    NASA Astrophysics Data System (ADS)

    Sahiner, Berkman; Hadjiiski, Lubomir M.; Chan, Heang-Ping; Paramagul, Chintana; Nees, Alexis; Helvie, Mark; Shi, Jiazheng

    2008-03-01

    The purpose of this study was to develop and evaluate computer-extracted features for characterizing mammographic mass margins according to BI-RADS spiculated and circumscribed categories. The mass was automatically segmented using an active contour model. A spiculation measure for a pixel on the mass boundary was defined by using the angular difference between the image gradient vector and the normal to the mass, averaged over pixels in a spiculation search region. For the circumscribed margin feature, the angular difference between the principal eigenvector of the Hessian matrix and the normal to the mass was estimated in a band of pixels centered at each point on the boundary, and the feature was extracted from the resulting profile along the boundary. Three MQSA radiologists provided BI-RADS margin ratings for a data set of 198 regions of interest containing breast masses. The features were evaluated with respect to the individual radiologists' characterization using receiver operating characteristic (ROC) analysis, as well as with respect to that from the majority rule, in which a mass was labeled as spiculated (circumscribed) if it was characterized as such by 2 or 3 radiologists, and non-spiculated (non-circumscribed) otherwise. We also investigated the performance of the features for consensus masses, defined as those labeled as spiculated (circumscribed) or nonspiculated (non-circumscribed) by all three radiologists. When masses were labeled according to radiologists R1, R2, and R3 individually, the spiculation feature had an area A z under the ROC curve of 0.90+/-0.04, 0.90+/-0.03, 0.88+/-0.03, respectively, while the circumscribed margin feature had an A z value of 0.77+/-0.04, 0.74+/-0.04, and 0.80+/-0.03, respectively. When masses were labeled according to the majority rule, the A z values for the spiculation and the circumscribed margin features were 0.92+/-0.03 and 0.80+/-+/-0.03, respectively. When only the consensus masses were considered, the A z

  13. Are Qualitative Assessments of Background Parenchymal Enhancement, Amount of Fibroglandular Tissue on MR Images, and Mammographic Density Associated with Breast Cancer Risk?

    PubMed Central

    Dontchos, Brian N.; Partridge, Savannah C.; Korde, Larissa A.; Lam, Diana L.; Scheel, John R.; Peacock, Sue; Lehman, Constance D.

    2015-01-01

    Purpose To investigate whether qualitative magnetic resonance (MR) imaging assessments of background parenchymal enhancement (BPE), amount of fibroglandular tissue (FGT), and mammographic density are associated with risk of developing breast cancer in women who are at high risk. Materials and Methods In this institutional review board–approved HIPAA-compliant retrospective study, all screening breast MR images obtained from January 2006 to December 2011 in women aged 18 years or older and at high risk for but without a history of breast cancer were identified. Women in whom breast cancer was diagnosed after index MR imaging comprised the cancer cohort, and one-to-one matching (age and BRCA status) of each woman with breast cancer to a control subject was performed by using MR images obtained in women who did not develop breast cancer with follow-up time maximized. Amount of BPE, BPE pattern (peripheral vs central), amount of FGT at MR imaging, and mammographic density were assessed on index images. Imaging features were compared between cancer and control cohorts by using conditional logistic regression. Results Twenty-three women at high risk (mean age, 47 years ± 10 [standard deviation]; six women had BRCA mutations) with no history of breast cancer underwent screening breast MR imaging; in these women, a diagnosis of breast cancer (invasive, n = 12; in situ, n = 11) was made during the follow-up interval. Women with mild, moderate, or marked BPE were nine times more likely to receive a diagnosis of breast cancer during the follow-up interval than were those with minimal BPE (P = .007; odds ratio = 9.0; 95% confidence interval: 1.1, 71.0). BPE pattern, MR imaging amount of FGT, and mammographic density were not significantly different between the cohorts (P = .5, P = .5, and P = .4, respectively). Conclusion Greater BPE was associated with a higher probability of developing breast cancer in women at high risk for cancer and warrants further study. © RSNA

  14. Ductal Breast Carcinoma In Situ: Mammographic Features and Its Relation to Prognosis and Tumour Biology in a Population Based Cohort

    PubMed Central

    Sollie, Thomas; Blomqvist, Carl; Abdsaleh, Shahin; Liljegren, Göran

    2017-01-01

    Casting-type calcifications and a histopathological picture with cancer-filled duct-like structures have been presented as breast cancer with neoductgenesis. We correlated mammographic features and histopathological neoductgenesis with prognosis in a DCIS cohort with long follow-up. Mammographic features were classified into seven groups according to Tabár. Histopathological neoductgenesis was defined by concentration of ducts, lymphocyte infiltration, and periductal fibrosis. Endpoints were ipsilateral (IBE) in situ and invasive events. Casting-type calcifications and neoductgenesis were both related to high nuclear grade, ER- and PR-negativity, and HER2 overexpression but not to each other. Casting-type calcifications and neoductgenesis were both related to a nonsignificant lower risk of invasive IBE, HR 0.38 (0.13–1.08) and 0.82 (0.29–2.27), respectively, and the HR of an in situ IBE was 0.90 (0.41–1.95) and 1.60 (0.75–3.39), respectively. Casting-type calcifications could not be related to a worse prognosis in DCIS. We cannot explain why a more aggressive phenotype of DCIS did not correspond to a worse prognosis. Further studies on how the progression from in situ to invasive carcinoma is driven are needed. PMID:28286675

  15. Assessment of a Four-View Mammographic Image Feature Based Fusion Model to Predict Near-Term Breast Cancer Risk.

    PubMed

    Tan, Maxine; Pu, Jiantao; Cheng, Samuel; Liu, Hong; Zheng, Bin

    2015-10-01

    The purpose of this study was to develop and assess a new quantitative four-view mammographic image feature based fusion model to predict the near-term breast cancer risk of the individual women after a negative screening mammography examination of interest. The dataset included fully-anonymized mammograms acquired on 870 women with two sequential full-field digital mammography examinations. For each woman, the first "prior" examination in the series was interpreted as negative (not recalled) during the original image reading. In the second "current" examination, 430 women were diagnosed with pathology verified cancers and 440 remained negative ("cancer-free"). For each of four bilateral craniocaudal and mediolateral oblique view images of left and right breasts, we computed and analyzed eight groups of global mammographic texture and tissue density image features. A risk prediction model based on three artificial neural networks was developed to fuse image features computed from two bilateral views of four images. The risk model performance was tested using a ten-fold cross-validation method and a number of performance evaluation indices including the area under the receiver operating characteristic curve (AUC) and odds ratio (OR). The highest AUC = 0.725 ± 0.026 was obtained when the model was trained by gray-level run length statistics texture features computed on dense breast regions, which was significantly higher than the AUC values achieved using the model trained by only two bilateral one-view images (p < 0.02). The adjustable OR values monotonically increased from 1.0 to 11.8 as model-generated risk score increased. The regression analysis of OR values also showed a significant increase trend in slope (p < 0.01). As a result, this preliminary study demonstrated that a new four-view mammographic image feature based risk model could provide useful and supplementary image information to help predict the near-term breast cancer risk.

  16. Predicting error in detecting mammographic masses among radiology trainees using statistical models based on BI-RADS features

    SciTech Connect

    Grimm, Lars J. Ghate, Sujata V.; Yoon, Sora C.; Kim, Connie; Kuzmiak, Cherie M.; Mazurowski, Maciej A.

    2014-03-15

    Purpose: The purpose of this study is to explore Breast Imaging-Reporting and Data System (BI-RADS) features as predictors of individual errors made by trainees when detecting masses in mammograms. Methods: Ten radiology trainees and three expert breast imagers reviewed 100 mammograms comprised of bilateral medial lateral oblique and craniocaudal views on a research workstation. The cases consisted of normal and biopsy proven benign and malignant masses. For cases with actionable abnormalities, the experts recorded breast (density and axillary lymph nodes) and mass (shape, margin, and density) features according to the BI-RADS lexicon, as well as the abnormality location (depth and clock face). For each trainee, a user-specific multivariate model was constructed to predict the trainee's likelihood of error based on BI-RADS features. The performance of the models was assessed using area under the receive operating characteristic curves (AUC). Results: Despite the variability in errors between different trainees, the individual models were able to predict the likelihood of error for the trainees with a mean AUC of 0.611 (range: 0.502–0.739, 95% Confidence Interval: 0.543–0.680,p < 0.002). Conclusions: Patterns in detection errors for mammographic masses made by radiology trainees can be modeled using BI-RADS features. These findings may have potential implications for the development of future educational materials that are personalized to individual trainees.

  17. Modeling error in assessment of mammographic image features for improved computer-aided mammography training: initial experience

    NASA Astrophysics Data System (ADS)

    Mazurowski, Maciej A.; Tourassi, Georgia D.

    2011-03-01

    In this study we investigate the hypothesis that there exist patterns in erroneous assessment of BI-RADS image features among radiology trainees when performing diagnostic interpretation of mammograms. We also investigate whether these error making patterns can be captured by individual user models. To test our hypothesis we propose a user modeling algorithm that uses the previous readings of a trainee to identify whether certain BI-RADS feature values (e.g. "spiculated" value for "margin" feature) are associated with higher than usual likelihood that the feature will be assessed incorrectly. In our experiments we used readings of 3 radiology residents and 7 breast imaging experts for 33 breast masses for the following BI-RADS features: parenchyma density, mass margin, mass shape and mass density. The expert readings were considered as the gold standard. Rule-based individual user models were developed and tested using the leave one-one-out crossvalidation scheme. Our experimental evaluation showed that the individual user models are accurate in identifying cases for which errors are more likely to be made. The user models captured regularities in error making for all 3 residents. This finding supports our hypothesis about existence of individual error making patterns in assessment of mammographic image features using the BI-RADS lexicon. Explicit user models identifying the weaknesses of each resident could be of great use when developing and adapting a personalized training plan to meet the resident's individual needs. Such approach fits well with the framework of adaptive computer-aided educational systems in mammography we have proposed before.

  18. Modeling resident error-making patterns in detection of mammographic masses using computer-extracted image features: preliminary experiments

    NASA Astrophysics Data System (ADS)

    Mazurowski, Maciej A.; Zhang, Jing; Lo, Joseph Y.; Kuzmiak, Cherie M.; Ghate, Sujata V.; Yoon, Sora

    2014-03-01

    Providing high quality mammography education to radiology trainees is essential, as good interpretation skills potentially ensure the highest benefit of screening mammography for patients. We have previously proposed a computer-aided education system that utilizes trainee models, which relate human-assessed image characteristics to interpretation error. We proposed that these models be used to identify the most difficult and therefore the most educationally useful cases for each trainee. In this study, as a next step in our research, we propose to build trainee models that utilize features that are automatically extracted from images using computer vision algorithms. To predict error, we used a logistic regression which accepts imaging features as input and returns error as output. Reader data from 3 experts and 3 trainees were used. Receiver operating characteristic analysis was applied to evaluate the proposed trainee models. Our experiments showed that, for three trainees, our models were able to predict error better than chance. This is an important step in the development of adaptive computer-aided education systems since computer-extracted features will allow for faster and more extensive search of imaging databases in order to identify the most educationally beneficial cases.

  19. Using computer-extracted image features for modeling of error-making patterns in detection of mammographic masses among radiology residents

    SciTech Connect

    Zhang, Jing Ghate, Sujata V.; Yoon, Sora C.; Lo, Joseph Y.; Kuzmiak, Cherie M.; Mazurowski, Maciej A.

    2014-09-15

    Purpose: Mammography is the most widely accepted and utilized screening modality for early breast cancer detection. Providing high quality mammography education to radiology trainees is essential, since excellent interpretation skills are needed to ensure the highest benefit of screening mammography for patients. The authors have previously proposed a computer-aided education system based on trainee models. Those models relate human-assessed image characteristics to trainee error. In this study, the authors propose to build trainee models that utilize features automatically extracted from images using computer vision algorithms to predict likelihood of missing each mass by the trainee. This computer vision-based approach to trainee modeling will allow for automatically searching large databases of mammograms in order to identify challenging cases for each trainee. Methods: The authors’ algorithm for predicting the likelihood of missing a mass consists of three steps. First, a mammogram is segmented into air, pectoral muscle, fatty tissue, dense tissue, and mass using automated segmentation algorithms. Second, 43 features are extracted using computer vision algorithms for each abnormality identified by experts. Third, error-making models (classifiers) are applied to predict the likelihood of trainees missing the abnormality based on the extracted features. The models are developed individually for each trainee using his/her previous reading data. The authors evaluated the predictive performance of the proposed algorithm using data from a reader study in which 10 subjects (7 residents and 3 novices) and 3 experts read 100 mammographic cases. Receiver operating characteristic (ROC) methodology was applied for the evaluation. Results: The average area under the ROC curve (AUC) of the error-making models for the task of predicting which masses will be detected and which will be missed was 0.607 (95% CI,0.564-0.650). This value was statistically significantly different

  20. X-ray absorptiometry of the breast using mammographic exposure factors: application to units featuring automatic beam quality selection.

    PubMed

    Kotre, C J

    2010-06-01

    A number of studies have identified the relationship between the visual appearance of high breast density at mammography and an increased risk of breast cancer. Approaches to quantify the amount of glandular tissue within the breast from mammography have so far concentrated on image-based methods. Here, it is proposed that the X-ray parameters automatically selected by the mammography unit can be used to estimate the thickness of glandular tissue overlying the automatic exposure sensor area, provided that the unit can be appropriately calibrated. This is a non-trivial task for modern mammography units that feature automatic beam quality selection, as the number of tube potential and X-ray target/filter combinations used to cover the range of breast sizes and compositions can be large, leading to a potentially unworkable number of curve fits and interpolations. Using appropriate models for the attenuation of the glandular breast in conjunction with a constrained set of physical phantom measurements, it is demonstrated that calibration for X-ray absorptiometry can be achieved despite the large number of possible exposure factor combinations employed by modern mammography units. The main source of error on the estimated glandular tissue thickness using this method is shown to be uncertainty in the measured compressed breast thickness. An additional correction for this source of error is investigated and applied. Initial surveys of glandular thickness for a cohort of women undergoing breast screening are presented.

  1. Women's features and inter-/intra-rater agreement on mammographic density assessment in full-field digital mammograms (DDM-SPAIN).

    PubMed

    Pérez-Gómez, Beatriz; Ruiz, Franciso; Martínez, Inmaculada; Casals, María; Miranda, Josefa; Sánchez-Contador, Carmen; Vidal, Carmen; Llobet, Rafael; Pollán, Marina; Salas, Dolores

    2012-02-01

    Measurement of mammographic density (MD), one of the leading risk factors for breast cancer, still relies on subjective assessment. However, the consistency of MD measurement in full-digital mammograms has yet to be evaluated. We studied inter- and intra-rater agreement with respect to estimation of breast density in full-digital mammograms, and tested whether any of the women's characteristics might have some influence on them. After an initial training period, three experienced radiologists estimated MD using Boyd scale in a left breast cranio-caudal mammogram of 1,431 women, recruited at three Spanish screening centres. A subgroup of 50 randomly selected images was read twice to estimate short-term intra-rater agreement. In addition, a reading of 1,428 of the images, performed 2 years before by one rater, was used to estimate long-term intra-rater agreement. Pair-wise weighted kappas with 95% bootstrap confidence intervals were calculated. Dichotomous variables were defined to identify mammograms in which any rater disagreed with other raters or with his/her own assessment, respectively. The association between disagreement and women's characteristics was tested using multivariate mixed logistic models, including centre as a random-effects term, and taking into account repeated measures when required. All quadratic-weighted kappa values for inter- and intra-rater agreement were excellent (higher than 0.80). None of the studied women's features, i.e. body mass index, brassiere size, menopause, nulliparity, lactation or current hormonal therapy, was associated with higher risk of inter- or intra-rater disagreement. However, raters differed significantly more in images that were classified in the higher-density MD categories, and disagreement in intra-rater assessment was also lower in low-density mammograms. The reliability of MD assessment in full-field digital mammograms is comparable to that for original or digitised images. The reassuring lack of association

  2. Qualitative features of the evolution of some polar satellite orbits

    NASA Astrophysics Data System (ADS)

    Vashkov'yak, M. A.

    2016-01-01

    Two special cases of the problem of the secular perturbations in the orbital elements of a satellite with a negligible mass produced by the joint influence of the oblateness of the central planet and the attraction by its most massive (or main) satellites and the Sun are considered. These cases are among the integrable ones in the general nonintegrable evolution problem. The first case is realized when the plane of the satellite orbit and the rotation axis of the planet lie in its orbital plane. The second case is realized when the plane of the satellite orbit is orthogonal to the line of intersection between the equatorial and orbital planes of the planet. The corresponding particular solutions correspond to those polar satellite orbits for which the main qualitative features of the evolution of the eccentricity and pericenter argument are described here. Families of integral curves have been constructed in the phase plane of these elements for the satellite systems of Jupiter, Saturn, and Uranus.

  3. Development of terminology for mammographic techniques for radiological technologists.

    PubMed

    Yagahara, Ayako; Yokooka, Yuki; Tsuji, Shintaro; Nishimoto, Naoki; Uesugi, Masahito; Muto, Hiroshi; Ohba, Hisateru; Kurowarabi, Kunio; Ogasawara, Katsuhiko

    2011-07-01

    We are developing a mammographic ontology to share knowledge of the mammographic domain for radiologic technologists, with the aim of improving mammographic techniques. As a first step in constructing the ontology, we used mammography reference books to establish mammographic terminology for identifying currently available knowledge. This study proceeded in three steps: (1) determination of the domain and scope of the terminology, (2) lexical extraction, and (3) construction of hierarchical structures. We extracted terms mainly from three reference books and constructed the hierarchical structures manually. We compared features of the terms extracted from the three reference books. We constructed a terminology consisting of 440 subclasses grouped into 19 top-level classes: anatomic entity, image quality factor, findings, material, risk, breast, histological classification of breast tumors, role, foreign body, mammographic technique, physics, purpose of mammography examination, explanation of mammography examination, image development, abbreviation, quality control, equipment, interpretation, and evaluation of clinical imaging. The number of terms that occurred in the subclasses varied depending on which reference book was used. We developed a terminology of mammographic techniques for radiologic technologists consisting of 440 terms.

  4. Distinguishing Features and Similarities Between Descriptive Phenomenological and Qualitative Description Research.

    PubMed

    Willis, Danny G; Sullivan-Bolyai, Susan; Knafl, Kathleen; Cohen, Marlene Z

    2016-09-01

    Scholars who research phenomena of concern to the discipline of nursing are challenged with making wise choices about different qualitative research approaches. Ultimately, they want to choose an approach that is best suited to answer their research questions. Such choices are predicated on having made distinctions between qualitative methodology, methods, and analytic frames. In this article, we distinguish two qualitative research approaches widely used for descriptive studies: descriptive phenomenological and qualitative description. Providing a clear basis that highlights the distinguishing features and similarities between descriptive phenomenological and qualitative description research will help students and researchers make more informed choices in deciding upon the most appropriate methodology in qualitative research. We orient the reader to distinguishing features and similarities associated with each approach and the kinds of research questions descriptive phenomenological and qualitative description research address.

  5. Clinicopathologic, mammographic, and sonographic features in 1187 patients with pure ductal carcinoma in situ of the breast by estrogen receptor status

    PubMed Central

    Rauch, Gaiane M.; Kuerer, Henry M.; Scoggins, Marion E.; Fox, Patricia S.; Benveniste, Ana P.; Park, Young Mi; Lari, Sara A.; Hobbs, Brian P.; Adrada, Beatriz E.; Krishnamurthy, Savitri; Yang, Wei T.

    2014-01-01

    Background The clinicopathologic, mammographic, and sonographic findings in patients with pure ductal carcinoma in situ (DCIS) were assessed by estrogen receptor (ER) expression. Methods After institutional review board approval, patients with pure DCIS evaluated from January 1996 to July 2009 with known ER status and available imaging were identified. Images were reviewed per the ACR BI-RADS® lexicon (4th edition). Clinical, pathologic, and imaging characteristics were analyzed by ER status using t-test, chi-square test, and Fisher’s exact test. Results Of 1219 patients with pure DCIS and known ER status identified, 1187 with complete data were included. Mammography was performed in all 1187 patients and sonography in 519 (44%). There were 972 (82%) patients with ER-positive and 215 (18%) with ER-negative disease. ER-negative DCIS was more likely to be high grade (93% vs 44%, p<0.0001), associated with comedonecrosis (64% vs 29%, p<0.0001), and multifocal (23% vs 15%, p=0.009). On sonography, ER-negative DCIS was more likely to be visible (61% vs 46%, p=0.004), larger (mean size, 2.3 vs 1.6 cm, p=0.006), and show posterior shadowing (53% vs 28%, p=0.006). Mastectomy was more frequently performed for ER-negative DCIS (47% vs 37%, p=0.008). Palpable DCIS was visible on sonography in 55% of cases and mammography in 81%. Compared with ER-positive palpable DCIS, ER-negative palpable DCIS was larger and more likely to be visible on sonography. Compared with ER-positive noncalcified DCIS, ER-negative noncalcified DCIS was less likely to be visible on mammography. Conclusion ER-positive and ER-negative pure DCIS have different clinicopathologic and imaging characteristics. ER-negative DCIS is associated with worse prognostic factors then ER-positive DCIS. On sonography, ER-negative DCIS is more frequently visible than ER-positive DCIS, tends to be larger, and more frequently demonstrates posterior shadowing. PMID:23774990

  6. Qualitative Features of High Lift Hovering Dynamics and Inertial Manifolds

    NASA Astrophysics Data System (ADS)

    Gustafson, K.; Leben, R.; McArthur, J.; Mundt, M.

    1996-03-01

    Hovering aerodynamics, such as that practiced by dragonflys, hummingbirds, and certain other small insects, utilizes special patterns of vorticity to generate high lift flows. Such lift as we measure it computationally on the airfoil surface is in good agreement with downstream thrust measured in the physical laboratory. In this paper we examine the qualitative signatures of this dynamical system. A connection to the theory of inertial manifolds, more specifically the instance of time-dependent slow manifolds, is initiated. Additional interest attaches to the fact that in our compact computational domain, the forcing is on the boundary. Because of its highly oscillatory nature, in this dynamics one proceeds rapidly up the bifurcation ladder at relatively low Reynolds numbers. Thus, aside from its intrinsic interest, the hover model provides an attractive vehicle for a better understanding of dynamical system attractor dynamics and inertial manifold theory.

  7. Breast image pre-processing for mammographic tissue segmentation.

    PubMed

    He, Wenda; Hogg, Peter; Juette, Arne; Denton, Erika R E; Zwiggelaar, Reyer

    2015-12-01

    During mammographic image acquisition, a compression paddle is used to even the breast thickness in order to obtain optimal image quality. Clinical observation has indicated that some mammograms may exhibit abrupt intensity change and low visibility of tissue structures in the breast peripheral areas. Such appearance discrepancies can affect image interpretation and may not be desirable for computer aided mammography, leading to incorrect diagnosis and/or detection which can have a negative impact on sensitivity and specificity of screening mammography. This paper describes a novel mammographic image pre-processing method to improve image quality for analysis. An image selection process is incorporated to better target problematic images. The processed images show improved mammographic appearances not only in the breast periphery but also across the mammograms. Mammographic segmentation and risk/density classification were performed to facilitate a quantitative and qualitative evaluation. When using the processed images, the results indicated more anatomically correct segmentation in tissue specific areas, and subsequently better classification accuracies were achieved. Visual assessments were conducted in a clinical environment to determine the quality of the processed images and the resultant segmentation. The developed method has shown promising results. It is expected to be useful in early breast cancer detection, risk-stratified screening, and aiding radiologists in the process of decision making prior to surgery and/or treatment.

  8. Qualitative research methods: key features and insights gained from use in infection prevention research.

    PubMed

    Forman, Jane; Creswell, John W; Damschroder, Laura; Kowalski, Christine P; Krein, Sarah L

    2008-12-01

    Infection control professionals and hospital epidemiologists are accustomed to using quantitative research. Although quantitative studies are extremely important in the field of infection control and prevention, often they cannot help us explain why certain factors affect the use of infection control practices and identify the underlying mechanisms through which they do so. Qualitative research methods, which use open-ended techniques, such as interviews, to collect data and nonstatistical techniques to analyze it, provide detailed, diverse insights of individuals, useful quotes that bring a realism to applied research, and information about how different health care settings operate. Qualitative research can illuminate the processes underlying statistical correlations, inform the development of interventions, and show how interventions work to produce observed outcomes. This article describes the key features of qualitative research and the advantages that such features add to existing quantitative research approaches in the study of infection control. We address the goal of qualitative research, the nature of the research process, sampling, data collection and analysis, validity, generalizability of findings, and presentation of findings. Health services researchers are increasingly using qualitative methods to address practical problems by uncovering interacting influences in complex health care environments. Qualitative research methods, applied with expertise and rigor, can contribute important insights to infection prevention efforts.

  9. Robust Feature Selection from Microarray Data Based on Cooperative Game Theory and Qualitative Mutual Information

    PubMed Central

    Mortazavi, Atiyeh; Moattar, Mohammad Hossein

    2016-01-01

    High dimensionality of microarray data sets may lead to low efficiency and overfitting. In this paper, a multiphase cooperative game theoretic feature selection approach is proposed for microarray data classification. In the first phase, due to high dimension of microarray data sets, the features are reduced using one of the two filter-based feature selection methods, namely, mutual information and Fisher ratio. In the second phase, Shapley index is used to evaluate the power of each feature. The main innovation of the proposed approach is to employ Qualitative Mutual Information (QMI) for this purpose. The idea of Qualitative Mutual Information causes the selected features to have more stability and this stability helps to deal with the problem of data imbalance and scarcity. In the third phase, a forward selection scheme is applied which uses a scoring function to weight each feature. The performance of the proposed method is compared with other popular feature selection algorithms such as Fisher ratio, minimum redundancy maximum relevance, and previous works on cooperative game based feature selection. The average classification accuracy on eleven microarray data sets shows that the proposed method improves both average accuracy and average stability compared to other approaches. PMID:27127506

  10. Robust Feature Selection from Microarray Data Based on Cooperative Game Theory and Qualitative Mutual Information.

    PubMed

    Mortazavi, Atiyeh; Moattar, Mohammad Hossein

    2016-01-01

    High dimensionality of microarray data sets may lead to low efficiency and overfitting. In this paper, a multiphase cooperative game theoretic feature selection approach is proposed for microarray data classification. In the first phase, due to high dimension of microarray data sets, the features are reduced using one of the two filter-based feature selection methods, namely, mutual information and Fisher ratio. In the second phase, Shapley index is used to evaluate the power of each feature. The main innovation of the proposed approach is to employ Qualitative Mutual Information (QMI) for this purpose. The idea of Qualitative Mutual Information causes the selected features to have more stability and this stability helps to deal with the problem of data imbalance and scarcity. In the third phase, a forward selection scheme is applied which uses a scoring function to weight each feature. The performance of the proposed method is compared with other popular feature selection algorithms such as Fisher ratio, minimum redundancy maximum relevance, and previous works on cooperative game based feature selection. The average classification accuracy on eleven microarray data sets shows that the proposed method improves both average accuracy and average stability compared to other approaches.

  11. Factors associated with mammographic decisions of Chinese-Australian women.

    PubMed

    Kwok, Cannas; Cant, Rosemary; Sullivan, Gerard

    2005-12-01

    BreastScreen (a free breast cancer screening service) has been implemented in Australia since 1991. Surveys conducted overseas consistently report that women of Chinese ancestry have low participation rates in breast cancer screening. Although Chinese women's use of breast cancer screening services has been investigated abroad, to date there are few studies of mammographic screening behavior among Chinese-Australian women. The purpose of this study is to explore and investigate the factors associated with mammographic decisions of Chinese-Australian women. Using a qualitative approach, in-depth interviews were conducted with 20 Chinese-Australian women. These were augmented by additional data from ethnographic observations. The findings show two facilitators: organizational factors (an invitation letter from BreastScreen and seniors' clubs arrangements) and the influence of 'significant others'. Barriers identified were fear perceptions of mammography, modesty and fear of stigmatization. This study provides a useful framework for designing and implementing mammographic screening services for Chinese-Australian women that may improve their participation rates.

  12. Computerized prediction of breast cancer risk: comparison between the global and local bilateral mammographic tissue asymmetry

    NASA Astrophysics Data System (ADS)

    Wang, Xingwei; Lederman, Dror; Tan, Jun; Wang, Xiao Hui; Zheng, Bin

    2011-03-01

    We have developed and preliminarily tested a new breast cancer risk prediction model based on computerized bilateral mammographic tissue asymmetry. In this study, we investigated and compared the performance difference of our risk prediction model when the bilateral mammographic tissue asymmetrical features were extracted in two different methods namely (1) the entire breast area and (2) the mirror-matched local strips between the left and right breast. A testing dataset including bilateral craniocaudal (CC) view images of 100 negative and 100 positive cases for developing breast abnormalities or cancer was selected from a large and diverse full-field digital mammography (FFDM) image database. To detect bilateral mammographic tissue asymmetry, a set of 20 initial "global" features were extracted from the entire breast areas of two bilateral mammograms in CC view and their differences were computed. Meanwhile, a pool of 16 local histogram-based statistic features was computed from eight mirror-matched strips between the left and right breast. Using a genetic algorithm (GA) to select optimal features, two artificial neural networks (ANN) were built to predict the risk of a test case developing cancer. Using the leave-one-case-out training and testing method, two GAoptimized ANNs yielded the areas under receiver operating characteristic (ROC) curves of 0.754+/-0.024 (using feature differences extracted from the entire breast area) and 0.726+/-0.026 (using the feature differences extracted from 8 pairs of local strips), respectively. The risk prediction model using either ANN is able to detect 58.3% (35/60) of cancer cases 6 to 18 months earlier at 80% specificity level. This study compared two methods to compute bilateral mammographic tissue asymmetry and demonstrated that bilateral mammographic tissue asymmetry was a useful breast cancer risk indicator with high discriminatory power.

  13. A new detection algorithm for microcalcification clusters in mammographic screening

    NASA Astrophysics Data System (ADS)

    Xie, Weiying; Ma, Yide; Li, Yunsong

    2015-05-01

    A novel approach for microcalcification clusters detection is proposed. At the first time, we make a short analysis of mammographic images with microcalcification lesions to confirm these lesions have much greater gray values than normal regions. After summarizing the specific feature of microcalcification clusters in mammographic screening, we make more focus on preprocessing step including eliminating the background, image enhancement and eliminating the pectoral muscle. In detail, Chan-Vese Model is used for eliminating background. Then, we do the application of combining morphology method and edge detection method. After the AND operation and Sobel filter, we use Hough Transform, it can be seen that the result have outperformed for eliminating the pectoral muscle which is approximately the gray of microcalcification. Additionally, the enhancement step is achieved by morphology. We make effort on mammographic image preprocessing to achieve lower computational complexity. As well known, it is difficult to robustly achieve mammograms analysis due to low contrast between normal and lesion tissues, there are also much noise in such images. After a serious preprocessing algorithm, a method based on blob detection is performed to microcalcification clusters according their specific features. The proposed algorithm has employed Laplace operator to improve Difference of Gaussians (DoG) function in terms of low contrast images. A preliminary evaluation of the proposed method performs on a known public database namely MIAS, rather than synthetic images. The comparison experiments and Cohen's kappa coefficients all demonstrate that our proposed approach can potentially obtain better microcalcification clusters detection results in terms of accuracy, sensitivity and specificity.

  14. Features of a Health-Oriented Education Program during Daily Commutes: A Qualitative Study

    PubMed Central

    Ramezankhani, Ali; Heydarabadi, Akbar Babaei; Ghaffari, Mohtasham; Mehrabi, Yadollah; Kazemi, Sadegh

    2016-01-01

    Introduction Today, despite scientific advances, many people spend more time and distance between home and their workplaces because of various economic and population reasons. The aim of this study was to identify features of an appropriate health education program during commutes for factory staff at Ardakan county (Yazd province, Iran). Methods This qualitative study was conducted via the phenomenological method in 2014. The population of this study was members of the staff of Ardakan Steel Company. Nineteen specialists and 11 members of the factory’s staff were invited to participate in the study, and data were collected using semi-structured interviews. The interviews took 20 to 40 minutes, and their content was analyzed using content analysis. Results Extraction of codes and themes and their placement in this study showed that an educational program during commutes should have nine features to have the desired effectiveness, i.e., the program must be audience-oriented, repeatable, participatory, technology-based, combinational, supportive, and motivational and interesting. Also, the program should have environmental and organizational support, and it must be evaluated for its effectiveness. Conclusion Considering appropriate features of a health education program in educational situations, especially interventions related to daily commutes, is very important because the effectiveness of such health-oriented educational programs must be ensured. PMID:27504166

  15. Force balancing in mammographic compression

    SciTech Connect

    Branderhorst, W. Groot, J. E. de; Lier, M. G. J. T. B. van; Grimbergen, C. A.; Neeter, L. M. F. H.; Heeten, G. J. den; Neeleman, C.

    2016-01-15

    Purpose: In mammography, the height of the image receptor is adjusted to the patient before compressing the breast. An inadequate height setting can result in an imbalance between the forces applied by the image receptor and the paddle, causing the clamped breast to be pushed up or down relative to the body during compression. This leads to unnecessary stretching of the skin and other tissues around the breast, which can make the imaging procedure more painful for the patient. The goal of this study was to implement a method to measure and minimize the force imbalance, and to assess its feasibility as an objective and reproducible method of setting the image receptor height. Methods: A trial was conducted consisting of 13 craniocaudal mammographic compressions on a silicone breast phantom, each with the image receptor positioned at a different height. The image receptor height was varied over a range of 12 cm. In each compression, the force exerted by the compression paddle was increased up to 140 N in steps of 10 N. In addition to the paddle force, the authors measured the force exerted by the image receptor and the reaction force exerted on the patient body by the ground. The trial was repeated 8 times, with the phantom remounted at a slightly different orientation and position between the trials. Results: For a given paddle force, the obtained results showed that there is always exactly one image receptor height that leads to a balance of the forces on the breast. For the breast phantom, deviating from this specific height increased the force imbalance by 9.4 ± 1.9 N/cm (6.7%) for 140 N paddle force, and by 7.1 ± 1.6 N/cm (17.8%) for 40 N paddle force. The results also show that in situations where the force exerted by the image receptor is not measured, the craniocaudal force imbalance can still be determined by positioning the patient on a weighing scale and observing the changes in displayed weight during the procedure. Conclusions: In mammographic breast

  16. Epidemiologic studies of isoflavones & mammographic density.

    PubMed

    Maskarinec, Gertraud; Verheus, Martijn; Tice, Jeffrey A

    2010-01-01

    Isoflavones, phytoestrogens in soy beans with estrogen-like properties, have been examined for their cancer protective effects. Mammographic density is a strong predictor of breast cancer. This review summarizes studies that have examined the association between isoflavones and breast density. Observational investigations in Hawaii and Singapore suggest slightly lower breast density among women of Asian descent with regular soy intake, but two larger studies from Japan and Singapore did not observe a protective effect. The findings from seven randomized trials with primarily Caucasian women indicate that soy or isoflavones do not modify mammographic density. Soy foods and isoflavone supplements within a nutritional range do not appear to modify breast cancer risk as assessed by mammographic density.

  17. Use of border information in the classification of mammographic masses

    NASA Astrophysics Data System (ADS)

    Varela, C.; Timp, S.; Karssemeijer, N.

    2006-01-01

    We are developing a new method to characterize the margin of a mammographic mass lesion to improve the classification of benign and malignant masses. Towards this goal, we designed features that measure the degree of sharpness and microlobulation of mass margins. We calculated these features in a border region of the mass defined as a thin band along the mass contour. The importance of these features in the classification of benign and malignant masses was studied in relation to existing features used for mammographic mass detection. Features were divided into three groups, each representing a different mass segment: the interior region of a mass, the border and the outer area. The interior and the outer area of a mass were characterized using contrast and spiculation measures. Classification was done in two steps. First, features representing each of the three mass segments were merged into a neural network classifier resulting in a single regional classification score for each segment. Secondly, a classifier combined the three single scores into a final output to discriminate between benign and malignant lesions. We compared the classification performance of each regional classifier and the combined classifier on a data set of 1076 biopsy proved masses (590 malignant and 486 benign) from 481 women included in the Digital Database for Screening Mammography. Receiver operating characteristic (ROC) analysis was used to evaluate the accuracy of the classifiers. The area under the ROC curve (Az) was 0.69 for the interior mass segment, 0.76 for the border segment and 0.75 for the outer mass segment. The performance of the combined classifier was 0.81 for image-based and 0.83 for case-based evaluation. These results show that the combination of information from different mass segments is an effective approach for computer-aided characterization of mammographic masses. An advantage of this approach is that it allows the assessment of the contribution of regions rather

  18. Vitamin D and Mammographic Findings

    PubMed Central

    Riedel, J.; Straub, L.; Wissing, J.; Artmann, A.; Schmidmayr, M.; Kiechle, M.; Seifert-Klauss, V. R.

    2016-01-01

    Introduction: Pleiotropic immune-modulatory and anti-proliferative effects of vitamin D and hopes to stop cancerogenesis have led to an increased interest in possible reduction of breast cancer with higher vitamin D levels. Mammographic density is an established risk factor for breast cancer risk, and its association with serum vitamin D is complex, as recent studies have shown. Patients and Methods: In this cross-sectional study, 1103 participants were recruited in the breast diagnostic unit of the Klinikum rechts der Isar, TU Munich. A standardised questionnaire and blood samples for 25-OH-vitamin D were taken on the day of mammography. Histologic results of biopsies in suspicious mammographies were documented. Results: In the 1090 data-sets analysed, vitamin D-deficiency was common among women under 40. Highest vitamin D values were observed in participants aged 60–69 years, but average values for all age cohorts were below 20 ng/ml of vitamin D. 15.6 % of all participants had very low vitamin D values (< 10 ng/ml), 51.3 % were vitamin D-deficient (10–19 ng/ml) and only 5.7 % were above 30 ng/ml, i.e. showed sufficient vitamin D. Patients with malignant results had vitamin D < 10 ng/ml more often (16.9 %; p = 0.61), and only 3.4 % in this group had sufficient vitamin D supply (> 30 ng/ml). There were no significant differences in vitamin D-levels between density groups according to the American College of Radiology (ACR) criteria. Conclusion: Vitamin D values were lower than in comparable US women. Up to now, there is no direct clinical evidence for a relationship between the risk for breast cancer and a specific vitamin D value. PMID:27239067

  19. Detection of lesions in mammographic structure

    NASA Astrophysics Data System (ADS)

    Burgess, Arthur E.; Jacobson, Francine L.; Judy, Philip F.

    1999-05-01

    This paper is a report on very surprising results from recent work on detection of real lesions in digitized mammograms. The experiments were done using a novel experimental procedure with hybrid images. The lesions (signals) were real tumor masses extracted from breast tissue specimen radiographs. In the detection experiments, the tumors were added to digitized normal mammographic backgrounds. The results of this new work have been both novel and very surprising. Contrast thresholds increased with increasing lesion size for lesions larger than approximately 1 mm in diameter. Earlier work with white noise, radiographic image noise, computed tomography (CT) noise and some types of patient structure have accustomed us to a particular relationship between lesion size and contrast for constant detectability. All previous contrast/detail (CD) diagrams have been similar, the contrast threshold decreases as lesion size increases and flattens at large lesion sizes. The CD diagram for lesion detection in mammographic structure is completely different. It will be shown that this is a consequence of the power-law dependence of the projected breast tissue structure spectral density on spatial frequency. Mammographic tissue structure power spectra have the form P(f) equals B/f(beta ), with an average exponent of approximately 3 (range from 2 to 4), and are approximately isotropic (small angular dependence). Results for two-alternative forced-choice (2AFC) signal detection experiments using 4 tumor lesions and one mathematically generated signal will be presented. These results are for an unbiased selection of mammographic backgrounds. It is possible that an additional understanding of the effects of breast structure on lesion detectability can be obtained by investigating detectability in various classes of mammographic backgrounds. This will be the subject of future research.

  20. Extraction of Qualitative Features from Sensor Data Using Windowed Fourier Transform

    NASA Technical Reports Server (NTRS)

    Amini, Abolfazl M.; Figueroa, Fenando

    2003-01-01

    In this paper, we use Matlab to model the health monitoring of a system through the information gathered from sensors. This implies assessment of the condition of the system components. Once a normal mode of operation is established any deviation from the normal behavior indicates a change. This change may be due to a malfunction of an element, a qualitative change, or a change due to a problem with another element in the network. For example, if one sensor indicates that the temperature in the tank has experienced a step change then a pressure sensor associated with the process in the tank should also experience a step change. The step up and step down as well as sensor disturbances are assumed to be exponential. An RC network is used to model the main process, which is step-up (charging), drift, and step-down (discharging). The sensor disturbances and spike are added while the system is in drift. The system is allowed to run for a period equal to three time constant of the main process before changes occur. Then each point of the signal is selected with a trailing data collected previously. Two trailing lengths of data are selected, one equal to two time constants of the main process and the other equal to two time constants of the sensor disturbance. Next, the DC is removed from each set of data and then the data are passed through a window followed by calculation of spectra for each set. In order to extract features the signal power, peak, and spectrum are plotted vs time. The results indicate distinct shapes corresponding to each process. The study is also carried out for a number of Gaussian distributed noisy cases.

  1. Task-Specific Optimization of Mammographic Systems

    DTIC Science & Technology

    2005-03-01

    by the equation: SNR Actual2 = DQE(O) . SNRI, i,,,i (1) where SNRIdeal was computed using a program by Boone to generate x-ray spectra2 and DQE(0...masses and microcalcifications. We have generated four image sets using the mammographic data obtained in 1.1. The first set was obtained at full dose...resolution and noise properties of the combined display and detector system using the generalized curve-fitting algorithm. After obtaining the

  2. Power spectral analysis of mammographic parenchymal patterns

    NASA Astrophysics Data System (ADS)

    Li, Hui; Giger, Maryellen L.; Olopade, Olufunmilayo I.

    2006-03-01

    Mammographic density and parenchymal patterns have been shown to be associated with the risk of developing breast cancer. Two groups of women: gene-mutation carriers and low-risk women were included in this study. Power spectral analysis was performed within parenchymal regions of 172 digitized craniocaudal normal mammograms of the BRCA1/BRCA2 gene-mutation carriers and those of women at low-risk of developing breast cancer. The power law spectrum of the form, P(f)=B/f β was evaluated for the mammographic patterns. Receiver Operating Characteristic (ROC) analysis was used to assess the performance of exponent β as a decision variable in the task of distinguishing between high and low-risk subjects. Power spectral analysis of mammograms demonstrated that mammographic parenchymal patterns have a power-law spectrum of the form, P(f)=B/f β where f is radial spatial frequency, with the average β values of 2.92 and 2.47 for the gene-mutation carriers and for the low-risk women, respectively. A z values of 0.90 and 0.89 were achieved in distinguishing between the gene-mutation carriers and the low-risk women with the individual image β value as the decision variable in the entire database and the age-matched group, respectively.

  3. 21 CFR 892.1710 - Mammographic x-ray system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Mammographic x-ray system. 892.1710 Section 892.1710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1710 Mammographic x-ray system....

  4. 21 CFR 892.1710 - Mammographic x-ray system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Mammographic x-ray system. 892.1710 Section 892.1710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1710 Mammographic x-ray system....

  5. 21 CFR 892.1710 - Mammographic x-ray system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Mammographic x-ray system. 892.1710 Section 892.1710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1710 Mammographic x-ray system....

  6. 21 CFR 892.1710 - Mammographic x-ray system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Mammographic x-ray system. 892.1710 Section 892.1710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1710 Mammographic x-ray system....

  7. 21 CFR 892.1710 - Mammographic x-ray system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Mammographic x-ray system. 892.1710 Section 892.1710 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1710 Mammographic x-ray system....

  8. Level set-based core segmentation of mammographic masses facilitating three stage (core, periphery, spiculation) analysis.

    PubMed

    Ball, John E; Bruce, Lori Mann

    2007-01-01

    We present mammographic mass core segmentation, based on the Chan-Vese level set method. The proposed method is analyzed via resulting feature efficacies. Additionally, the core segmentation method is used to investigate the idea of a three stage segmentation approach, i.e. segment the mass core, periphery, and spiculations (if any exist) and use features from these three segmentations to classify the mass as either benign or malignant. The proposed core segmentation method and a proposed end-to-end computer aided detection (CAD) system using a three stage segmentation are implemented and experimentally tested with a set of 60 mammographic images from the Digital Database of Screening Mammography. Receiver operating characteristic (ROC) curve AZ values for morphological and texture features extracted from the core segmentation are shown to be on par, or better, than those extracted from a periphery segmentation. The efficacy of the core segmentation features when combined with the periphery and spiculation segmentation features are shown to be feature set dependent. The proposed end-to-end system uses stepwise linear discriminant analysis for feature selection and a maximum likelihood classifier. Using all three stages (core + periphery + spiculations) results in an overall accuracy (OA) of 90% with 2 false negatives (FN). Since many CAD systems only perform a periphery analysis, adding core features could be a benefit to potentially increase OA and reduce FN cases.

  9. Mammographic breast density and serum phytoestrogen levels.

    PubMed

    Lowry, Sarah J; Sprague, Brian L; Aiello Bowles, Erin J; Hedman, Curtis J; Hemming, Jocelyn; Hampton, John M; Burnside, Elizabeth S; Sisney, Gale A; Buist, Diana S M; Trentham-Dietz, Amy

    2012-08-01

    Some forms of estrogen are associated with breast cancer risk as well as with mammographic density (MD), a strong marker of breast cancer risk. Whether phytoestrogen intake affects breast density, however, remains unclear. We evaluated the association between serum levels of phytoestrogens and MD in postmenopausal women. We enrolled 269 women, ages 55-70 yr, who received a screening mammogram and had no history of postmenopausal hormone use. Subjects completed a survey on diet and factors related to MD and provided a blood sample for analysis of 3 phytoestrogens: genistein, daidzein, and coumestrol. We examined whether mean percent MD was related to serum level of phytoestrogens, adjusting for age and body mass index. Genistein and daidzein levels correlated with self-reported soy consumption. Mean percent MD did not differ across women with different phytoestrogen levels. For example, women with nondetectable genistein levels had mean density of 11.0% [95% confidence intervals (CI) = 9.9-12.4], compared to 10.5% (95% CI = 8.0-13.7) and 11.2% (95% CI = 8.7-14.6) for < and ≥ median detectable levels, respectively. In a population with relatively low soy intake, serum phytoestrogens were not associated with mammographic density. Additional studies are needed to determine effects of higher levels, particularly given patterns of increasing phytoestrogen intake.

  10. Mammographic parenchymal texture as an imaging marker of hormonal activity: a comparative study between pre- and post-menopausal women

    NASA Astrophysics Data System (ADS)

    Daye, Dania; Bobo, Ezra; Baumann, Bethany; Ioannou, Antonios; Conant, Emily F.; Maidment, Andrew D. A.; Kontos, Despina

    2011-03-01

    Mammographic parenchymal texture patterns have been shown to be related to breast cancer risk. Yet, little is known about the biological basis underlying this association. Here, we investigate the potential of mammographic parenchymal texture patterns as an inherent phenotypic imaging marker of endogenous hormonal exposure of the breast tissue. Digital mammographic (DM) images in the cranio-caudal (CC) view of the unaffected breast from 138 women diagnosed with unilateral breast cancer were retrospectively analyzed. Menopause status was used as a surrogate marker of endogenous hormonal activity. Retroareolar 2.5cm2 ROIs were segmented from the post-processed DM images using an automated algorithm. Parenchymal texture features of skewness, coarseness, contrast, energy, homogeneity, grey-level spatial correlation, and fractal dimension were computed. Receiver operating characteristic (ROC) curve analysis was performed to evaluate feature classification performance in distinguishing between 72 pre- and 66 post-menopausal women. Logistic regression was performed to assess the independent effect of each texture feature in predicting menopause status. ROC analysis showed that texture features have inherent capacity to distinguish between pre- and post-menopausal statuses (AUC>0.5, p<0.05). Logistic regression including all texture features yielded an ROC curve with an AUC of 0.76. Addition of age at menarche, ethnicity, contraception use and hormonal replacement therapy (HRT) use lead to a modest model improvement (AUC=0.78) while texture features maintained significant contribution (p<0.05). The observed differences in parenchymal texture features between pre- and post- menopausal women suggest that mammographic texture can potentially serve as a surrogate imaging marker of endogenous hormonal activity.

  11. Qualitative Features Extraction from Sensor Data using Short-time Fourier Transform

    NASA Technical Reports Server (NTRS)

    Amini, Abolfazl M.; Figueroa, Fernando

    2004-01-01

    The information gathered from sensors is used to determine the health of a sensor. Once a normal mode of operation is established any deviation from the normal behavior indicates a change. This change may be due to a malfunction of the sensor(s) or the system (or process). The step-up and step-down features, as well as sensor disturbances are assumed to be exponential. An RC network is used to model the main process, which is defined by a step-up (charging), drift, and step-down (discharging). The sensor disturbances and spike are added while the system is in drift. The system runs for a period of at least three time-constants of the main process every time a process feature occurs (e.g. step change). The Short-Time Fourier Transform of the Signal is taken using the Hamming window. Three window widths are used. The DC value is removed from the windowed data prior to taking the FFT. The resulting three dimensional spectral plots provide good time frequency resolution. The results indicate distinct shapes corresponding to each process.

  12. Mammographic density, lobular involution, and risk of breast cancer

    PubMed Central

    Ginsburg, O M; Martin, L J; Boyd, N F

    2008-01-01

    In this review, we propose that age-related changes in mammographic density and breast tissue involution are closely related phenomena, and consider their potential relevance to the aetiology of breast cancer. We propose that the reduction in mammographic density that occurs with increasing age, parity and menopause reflects the involution of breast tissue. We further propose that age-related changes in both mammographic density and breast tissue composition are observable and measurable phenomena that resemble Pike's theoretical construct of ‘breast tissue ageing'. Extensive mammographic density and delayed breast involution are both associated with an increased risk of breast cancer and are consistent with the hypothesis of the Pike model that cumulative exposure of breast tissue to hormones and growth factors that stimulate cell division, as well as the accumulation of genetic damage in breast cells, are major determinants of breast cancer incidence. PMID:18781174

  13. Qualitative and quantitative comparison of colonic microendoscopy image features to histopathology

    NASA Astrophysics Data System (ADS)

    Prieto, Sandra P.; Powless, Amy J.; Lai, Keith; Laryea, Jonathan A.; Mizell, Jason S.; Muldoon, Timothy J.

    2015-03-01

    Colorectal cancer is the second leading cause of cancer deaths in the United States, affecting more than 130,000 Americans every year1. Determining tumor margins prior to surgical resection is essential to providing optimal treatment and reducing recurrence rates. Colorectal cancer recurrence can occur in up to 20% of cases, commonly within three years after curative treatment. Typically, when colorectal cancers are resected, a margin of normal tissue on both sides of the tumor is required. The minimum margin required for colon cancer is 5 cm and for the lower rectum 2 cm. However, usually more normal tissue is taken on both sides of the tumor because the blood supply to the entire segment is removed with the surgery and therefore the entire segment must be removed. Anastomotic recurrences may result from inadequate margins. Pathologists look at the margins to ensure that there is no residual tumor and this is usually documented in the pathology report. We have developed a portable, point-of-care fiber bundle microendoscopy imaging system for detection of abnormalities in colonic epithelial microstructure. The system comprises a laptop, a modified fiber bundle image guide with a 1mm active area diameter and custom LabVIEW interface, and is approved for imaging surgically resected colon tissue at the University of Arkansas for Medical Sciences. The microendoscopy probe provides high-resolution images of superficial epithelial histology in real-time to assist surgical guidance and to localize occult regions of dysplasia which may not be visible. Microendoscopy images of freshly resected human colonic epithelium were acquired using the microendoscopy device and subsequently mosaicked using custom post-processing software. Architectural changes in the glands were mapped to histopathology H&E slides taken from the precise location of the microendoscopy images. Qualitatively, glandular distortion and placement of image guide was used to map normal and dysplastic areas of

  14. Qualitative and quantitative comparison of colonic microendoscopy image features to histopathology

    PubMed Central

    Prieto, Sandra P.; Powless, Amy J.; Lai, Keith; Laryea, Jonathan A.; Mizell, Jason S.; Muldoon, Timothy J.

    2015-01-01

    Colorectal cancer is the second leading cause of cancer deaths in the United States, affecting more than 130,000 Americans every year1. Determining tumor margins prior to surgical resection is essential to providing optimal treatment and reducing recurrence rates. Colorectal cancer recurrence can occur in up to 20% of cases, commonly within three years after curative treatment. Typically, when colorectal cancers are resected, a margin of normal tissue on both sides of the tumor is required. The minimum margin required for colon cancer is 5 cm and for the lower rectum 2 cm. However, usually more normal tissue is taken on both sides of the tumor because the blood supply to the entire segment is removed with the surgery and therefore the entire segment must be removed. Anastomotic recurrences may result from inadequate margins. Pathologists look at the margins to ensure that there is no residual tumor and this is usually documented in the pathology report. We have developed a portable, point-of-care fiber bundle microendoscopy imaging system for detection of abnormalities in colonic epithelial microstructure. The system comprises a laptop, a modified fiber bundle image guide with a 1mm active area diameter and custom Lab VIEW interface, and is approved for imaging surgically resected colon tissue at the University of Arkansas for Medical Sciences. The microendoscopy probe provides high-resolution images of superficial epithelial histology in real-time to assist surgical guidance and to localize occult regions of dysplasia which may not be visible. Microendoscopy images of freshly resected human colonic epithelium were acquired using the microendoscopy device and subsequently mosaicked using custom post-processing software. Architectural changes in the glands were mapped to histopathology H&E slides taken from the precise location of the microendoscopy images. Qualitatively, glandular distortion and placement of image guide was used to map normal and dysplastic areas

  15. Impedance mammograph 3D phantom studies.

    PubMed

    Wtorek, J; Stelter, J; Nowakowski, A

    1999-04-20

    The results obtained using the Technical University of Gdansk Electroimpedance Mammograph (TUGEM) of a 3D phantom study are presented. The TUGEM system is briefly described. The hardware contains the measurement head and DSP-based identification modules controlled by a PC computer. A specially developed reconstruction algorithm, Regulated Correction Frequency Algebraic Reconstruction Technique (RCFART), is used to obtain 3D images. To visualize results, the Advance Visualization System (AVS) is used. It allows a powerful image processing on a fast workstation or on a high-performance computer. Results of three types of 3D conductivity perturbations used in the study (aluminum, Plexiglas, and cucumber) are shown. The relative volumes of perturbations less than 2% of the measurement chamber are easily evidenced.

  16. Development and application of a segmentation routine in a mammographic mass CAD system

    NASA Astrophysics Data System (ADS)

    Catarious, David M., Jr.; Baydush, Alan H.; Floyd, Carey E., Jr.

    2004-05-01

    The purpose of this paper is to present a new segmentation routine developed for mammographic masses. We previously developed a computer-aided detection (CAD) system for mammographic masses that employed a simple but imprecise segmentation procedure. To improve the systems performance, an iterative, linear segmentation routine was developed. The routine begins by employing a linear discriminant function to determine the optimal threshold between estimates of an objects interior and exterior pixels. After applying the threshold and identifying the objects outline, two constraints are applied to minimize the influence of extraneous background structures. Each iteration further refines the outline until the stopping criterion is reached. The segmentation algorithm was tested on a database of 181 mammographic images that contained forty-nine malignant and fifty benign masses. A set of suspicious regions of interest (ROIs) was found using the previous CAD system. Twenty features were measured from the regions before and after applying the new segmentation routine. The difference in the features discriminatory ability was examined via receiver operating characteristic (ROC) analysis. A significant performance difference was observed in many features, particularly those describing the object border. Free-response ROC (FROC) curves were utilized to examine how the overall CAD system performance changed with the inclusion of the segmentation routine. The FROC performance appeared to be improved, especially for malignant masses. When detecting 90% of the malignant masses, the previous system achieved 4.4 false positives per image (FPpI) compared to the post-segmentation systems 3.7 FPpI. At 85%, the respective FPpI are 4.1 and 2.1.

  17. Alcohol intake over the life course and mammographic density.

    PubMed

    Flom, Julie D; Ferris, Jennifer S; Tehranifar, Parisa; Terry, Mary Beth

    2009-10-01

    Alcohol intake is one of the few modifiable risk factors for breast cancer. Current alcohol intake has been associated with mammographic density, a strong intermediate marker of breast cancer risk, though few studies have examined the effect of both current and average lifetime alcohol intake. We interviewed 262 participants from a New York birth cohort (born 1959-1963) and obtained mammograms from 163 (71.5% of participants with a mammogram). We collected information on alcohol intake by beverage type separately for each decade of life. We used multivariable linear models to assess the associations between current and average lifetime alcohol intake and mammographic density using a quantitative measure of density from digitized images. Overall, current alcohol intake was more strongly associated with mammographic density than average lifetime alcohol intake; compared with nondrinkers, those with current intake of seven or more servings per week had on average 12.3% (95% CI: 4.3, 20.4) higher density, adjusted for average lifetime alcohol intake, age, and body mass index. We observed a consistent inverse association for red wine intake and mammographic density, suggesting that the positive association between mammographic density and overall alcohol intake was driven by other types of alcoholic beverages. Our findings support an association between current alcohol intake and increased mammographic density independent of the effect of average lifetime alcohol intake. If replicated, our study suggests that reducing current alcohol consumption, particularly beer and white wine intake, may be a means of reducing mammographic density regardless of intake earlier in life.

  18. Childhood factors associated with mammographic density in adult women.

    PubMed

    Lope, Virginia; Pérez-Gómez, Beatriz; Moreno, María Pilar; Vidal, Carmen; Salas-Trejo, Dolores; Ascunce, Nieves; Román, Isabel González; Sánchez-Contador, Carmen; Santamariña, María Carmen; Carrete, Jose Antonio Vázquez; Collado-García, Francisca; Pedraz-Pingarrón, Carmen; Ederra, María; Ruiz-Perales, Francisco; Peris, Mercé; Abad, Soledad; Cabanes, Anna; Pollán, Marina

    2011-12-01

    Growth and development factors could contribute to the development of breast cancer associated with an increase in mammographic density. This study examines the influence of certain childhood-related, socio-demographic and anthropometric variables on mammographic density in adult woman. The study covered 3574 women aged 45-68 years, participating in breast cancer-screening programmes in seven Spanish cities. Based on a craniocaudal mammogram, blind, anonymous measurement of mammographic density was made by a single radiologist, using Boyd's semiquantitative scale. Data associated with the early stages of life were obtained from a direct survey. Ordinal logistic regression and generalised linear models were employed to estimate the association between mammographic density and the variables covered by the questionnaire. Screening programme was introduced as a random effects term. Age, number of children, body mass index (BMI) and other childhood-related variables were used as adjustment variables, and stratified by menopausal status. A total of 811 women (23%) presented mammographic density of over 50%, and 5% of densities exceeded 75%. Our results show a greater prevalence of high mammographic density in women with low prepubertal weight (OR: 1.18; 95% CI: 1.02-1.36); marked prepubertal height (OR: 1.25; 95% CI: 0.97-1.60) and advanced age of their mothers at their birth (>39 years: OR: 1.28; 95% CI: 1.03-1.60); and a lower prevalence of high mammographic density in women with higher prepubertal weight, low birth weight and earlier menarche. The influence of these early-life factors may be explained by greater exposure to hormones and growth factors during the development of the breast gland, when breast tissue would be particularly susceptible to proliferative and carcinogenic stimulus.

  19. Characterization of difference of Gaussian filters in the detection of mammographic regions

    SciTech Connect

    Catarious, David M. Jr.; Baydush, Alan H.; Floyd, Carey E. Jr.

    2006-11-15

    In this article, we present a characterization of the effect of difference of Gaussians (DoG) filters in the detection of mammographic regions. DoG filters have been used previously in mammographic mass computer-aided detection (CAD) systems. As DoG filters are constructed from the subtraction of two bivariate Gaussian distributions, they require the specification of three parameters: the size of the filter template and the standard deviations of the constituent Gaussians. The influence of these three parameters in the detection of mammographic masses has not been characterized. In this work, we aim to determine how the parameters affect (1) the physical descriptors of the detected regions (2) the true and false positive rates, and (3) the classification performance of the individual descriptors. To this end, 30 DoG filters are created from the combination of three template sizes and four values for each of the Gaussians' standard deviations. The filters are used to detect regions in a study database of 181 craniocaudal-view mammograms extracted from the Digital Database for Screening Mammography. To describe the physical characteristics of the identified regions, morphological and textural features are extracted from each of the detected regions. Differences in the mean values of the features caused by altering the DoG parameters are examined through statistical and empirical comparisons. The parameters' effects on the true and false positive rate are determined by examining the mean malignant sensitivities and false positives per image (FPpI). Finally, the effect on the classification performance is described by examining the variation in FPpI at the point where 81% of the malignant masses in the study database are detected. Overall, the findings of the study indicate that increasing the standard deviations of the Gaussians used to construct a DoG filter results in a dramatic decrease in the number of regions identified at the expense of missing a small number of

  20. Characterization of difference of Gaussian filters in the detection of mammographic regions.

    PubMed

    Catarious, David M; Baydush, Alan H; Floyd, Carey E

    2006-11-01

    In this article, we present a characterization of the effect of difference of Gaussians (DoG) filters in the detection of mammographic regions. DoG filters have been used previously in mammographic mass computer-aided detection (CAD) systems. As DoG filters are constructed from the subtraction of two bivariate Gaussian distributions, they require the specification of three parameters: the size of the filter template and the standard deviations of the constituent Gaussians. The influence of these three parameters in the detection of mammographic masses has not been characterized. In this work, we aim to determine how the parameters affect (1) the physical descriptors of the detected regions, (2) the true and false positive rates, and (3) the classification performance of the individual descriptors. To this end, 30 DoG filters are created from the combination of three template sizes and four values for each of the Gaussians' standard deviations. The filters are used to detect regions in a study database of 181 craniocaudal-view mammograms extracted from the Digital Database for Screening Mammography. To describe the physical characteristics of the identified regions, morphological and textural features are extracted from each of the detected regions. Differences in the mean values of the features caused by altering the DoG parameters are examined through statistical and empirical comparisons. The parameters' effects on the true and false positive rate are determined by examining the mean malignant sensitivities and false positives per image (FPpI). Finally, the effect on the classification performance is described by examining the variation in FPpI at the point where 81% of the malignant masses in the study database are detected. Overall, the findings of the study indicate that increasing the standard deviations of the Gaussians used to construct a DoG filter results in a dramatic decrease in the number of regions identified at the expense of missing a small number

  1. A Review on Automatic Mammographic Density and Parenchymal Segmentation

    PubMed Central

    He, Wenda; Juette, Arne; Denton, Erika R. E.; Oliver, Arnau; Martí, Robert; Zwiggelaar, Reyer

    2015-01-01

    Breast cancer is the most frequently diagnosed cancer in women. However, the exact cause(s) of breast cancer still remains unknown. Early detection, precise identification of women at risk, and application of appropriate disease prevention measures are by far the most effective way to tackle breast cancer. There are more than 70 common genetic susceptibility factors included in the current non-image-based risk prediction models (e.g., the Gail and the Tyrer-Cuzick models). Image-based risk factors, such as mammographic densities and parenchymal patterns, have been established as biomarkers but have not been fully incorporated in the risk prediction models used for risk stratification in screening and/or measuring responsiveness to preventive approaches. Within computer aided mammography, automatic mammographic tissue segmentation methods have been developed for estimation of breast tissue composition to facilitate mammographic risk assessment. This paper presents a comprehensive review of automatic mammographic tissue segmentation methodologies developed over the past two decades and the evidence for risk assessment/density classification using segmentation. The aim of this review is to analyse how engineering advances have progressed and the impact automatic mammographic tissue segmentation has in a clinical environment, as well as to understand the current research gaps with respect to the incorporation of image-based risk factors in non-image-based risk prediction models. PMID:26171249

  2. Mammographic Breast Density Response to Aromatase Inhibition

    PubMed Central

    Vachon, Celine M.; Suman, Vera J.; Brandt, Kathleen R.; Kosel, Matthew L.; Buzdar, Aman U.; Olson, Janet E.; Wu, Fang-Fang; Flickinger, Lynn M.; Ursin, Giske; Elliott, Catherine R.; Shepherd, Lois; Weinshilboum, Richard M.; Goss, Paul E.; Ingle, James N.

    2013-01-01

    Purpose Mammographic breast density (MBD) is decreased by tamoxifen, but the effect of aromatase inhibitors (AI) is less clear. Experimental Design We enrolled early stage postmenopausal breast cancer patients initiating adjuvant AI therapy and ascertained mammograms before and at an average 10 months of AI therapy. We matched cases to healthy postmenopausal women (controls) from a large mammography screening cohort on age, baseline body mass index, baseline MBD and interval between mammograms. We estimated change in MBD using a computer-assisted thresholding program (Cumulus) and compared differences between cases and matched controls. Results In predominantly white women (96%), we found 14% of the 387 eligible cases had a MBD reduction of at least 5% after an average of 10 months of AI therapy. MBD reductions were associated with higher baseline MBD, AI use for more than 12 months and prior postmenopausal hormone use. Comparing each case to her matched control, there was no evidence of an association of change in MBD with AI therapy (median case-control difference among 369 pairs was −0.1% (10th and 90th percentile: −5.9%, 5.2%) p=0.51). Case-control differences were similar by type of AI (p’s 0.41 and 0.56); prior use of postmenopausal hormones (p=0.85); baseline MBD (p=0.55); or length of AI therapy (p=0.08). Conclusions In postmenopausal women treated with AIs, 14% of cases had a MBD reduction of >5%, but these decreases did not differ from matched controls. These data suggest that MBD is not a clinically useful biomarker for predicting the value of AI therapy in white postmenopausal women. PMID:23468058

  3. Effect on biopsy technique of the breast imaging reporting and data system (BI-RADS) for nonpalpable mammographic abnormalities

    PubMed Central

    Ball, Chad G.; Butchart, Michael; MacFarlane, John K.

    2002-01-01

    Objective To determine if the breast imaging reporting and data system (BI-RADS) defines a group of patients with mammographic abnormalities in whom stereotactic core needle biopsy (SCNB) is appropriate. Design A blinded retrospective validation sample. Setting A university-affiliated hospital. Patients One hundred and nine consecutive patients who underwent fine-wire localization breast biopsy (FWLB) between Jan. 1, 1994, and June 1, 1999, with a known final pathological diagnosis. Intervention Blinded mammographic review and classification using the BI-RADS; review of corresponding pathological findings from FWLBs. Outcome measures Correlation of pathological findings with each BI-RADS category and analysis of the predictive value of clinical and radiologic features. Results BI-RADS findings were as follows: 0 malignant lesions in 10 category 3 cases, 18 malignant lesions (3 in situ, 15 invasive) in 68 category 4 cases and 24 malignant lesions (8 in situ and 16 invasive) in 31 category 5 cases. There was 1 malignant lesion in 22 category 4 cases in women younger than 50 years. Conclusions SCNB should be applied to BI-RADS categories 3 and 4 (< 50 yr of age). FWLB should be reserved for category 4 (> 50 yr of age) and category 5 cases. This algorithm will reduce the morbidity and cost of breast biopsies in patients with nonpalpable mammographic abnormalities. PMID:12174979

  4. Mammographic density measured as changes in tissue structure caused by HRT

    NASA Astrophysics Data System (ADS)

    Raundahl, Jakob; Loog, Marco; Nielsen, Mads

    2006-03-01

    Numerous studies have investigated the relation between mammographic density and breast cancer risk. These studies indicate that women with high breast density have a four to six fold risk increase. An investigation of whether or not this relation is causal is important for, e.g., hormone replacement therapy (HRT), which has been shown to actually increase the density. No gold standard for automatic assessment of mammographic density exists. Manual methods such as Wolfe patterns and BI-RADS are helpful for communication of diagnostic sensitivity, but they are both time consuming and crude. They may be sufficient in certain cases and for single measurements, but for serial, temporal analysis it is necessary to be able to detect more subtle changes and, in addition, to be more reproducible. In this work an automated method for measuring the effect of HRT w.r.t. changes in biological density in the breast is presented. This measure is a novel measure, which provides structural information orthogonal to intensity-based methods. Hessian eigenvalues at different scales are used as features and a clustering of these is employed to divide a mammogram into four structurally different areas. Subsequently, based on the relative size of the areas, a density score is determined. In the experiments, two sets of mammograms of 50 patients from a double blind, placebo controlled HRT experiment were used. The change in density for the HRT group, measured with the new method, was significantly higher (p = 0.0002) than the change in the control group.

  5. Prenatal smoke exposure and mammographic density in mid-life

    PubMed Central

    Terry, M. B.; Schaefer, C. A.; Flom, J. D.; Wei, Y.; Tehranifar, P.; Liao, Y.; Buka, S.; Michels, K. B.

    2012-01-01

    Tobacco smoke has both carcinogenic effects and anti-estrogenic properties and its inconsistent association with breast cancer risk in observational studies may be because of these competing effects across the lifecourse. We conducted a prospective study of prenatal smoke exposure, childhood household smoke exposure, and adult active smoke exposure and mammographic density, a strong intermediate marker of breast cancer risk, in an adult follow-up of existing US birth cohorts. Specifically, we followed up women who were born between 1959 and 1967 and whose mothers participated in either the Collaborative Perinatal Project (Boston and Providence sites) or the Childhood Health and Development Study in California. Of the 1134 women interviewed in adulthood (ranging in age from 39 to 49 years at interview), 79% had a screening mammogram. Cigarette smoking was reported by mothers at the time of their pregnancy; 40% of mothers smoked while pregnant. Women whose mothers smoked during pregnancy had a 3.1% (95% confidence interval (CI) = −6.0%, −0.2%) lower mammographic density than women whose mothers did not smoke during pregnancy. When we further accounted for adult body mass index and adult smoking status, the association remained (β = −2.7, 95% CI = −5.0, −0.3).When we examined patterns of smoking, prenatal smoke exposure without adult smoke exposure was associated with a 5.6% decrease in mammographic density (β = −5.6, 95% CI = −9.6, −1.6). Given the strength of mammographic density as an intermediate marker for breast cancer, the inverse associations between mammographic density and smoking patterns across the lifecourse may help explain the complex association between cigarette smoking and breast cancer risk. PMID:23378890

  6. A completely automated CAD system for mass detection in a large mammographic database

    SciTech Connect

    Bellotti, R.; De Carlo, F.; Tangaro, S.

    2006-08-15

    Mass localization plays a crucial role in computer-aided detection (CAD) systems for the classification of suspicious regions in mammograms. In this article we present a completely automated classification system for the detection of masses in digitized mammographic images. The tool system we discuss consists in three processing levels: (a) Image segmentation for the localization of regions of interest (ROIs). This step relies on an iterative dynamical threshold algorithm able to select iso-intensity closed contours around gray level maxima of the mammogram. (b) ROI characterization by means of textural features computed from the gray tone spatial dependence matrix (GTSDM), containing second-order spatial statistics information on the pixel gray level intensity. As the images under study were recorded in different centers and with different machine settings, eight GTSDM features were selected so as to be invariant under monotonic transformation. In this way, the images do not need to be normalized, as the adopted features depend on the texture only, rather than on the gray tone levels, too. (c) ROI classification by means of a neural network, with supervision provided by the radiologist's diagnosis. The CAD system was evaluated on a large database of 3369 mammographic images [2307 negative, 1062 pathological (or positive), containing at least one confirmed mass, as diagnosed by an expert radiologist]. To assess the performance of the system, receiver operating characteristic (ROC) and free-response ROC analysis were employed. The area under the ROC curve was found to be A{sub z}=0.783{+-}0.008 for the ROI-based classification. When evaluating the accuracy of the CAD against the radiologist-drawn boundaries, 4.23 false positives per image are found at 80% of mass sensitivity.

  7. Study of digital mammographic equipments by phantom image quality.

    PubMed

    Mayo, P; Rodenas, F; Verdú, G; Campayo, J M; Villaescusa, J I

    2006-01-01

    Nowadays, the digital radiographic equipments are replacing the traditional film-screen equipments and it is necessary to update the parameters to guarantee the quality of the process. Contrast-detail phantoms are applied to digital radiography to study the threshold contrast-detail sensitivity at operation conditions of the equipment. The phantom that is studied in this work is CDMAM 3.4. One of the most extended indexes to measure the image quality in an objective way is the image quality figure (IQF). The aim of this work is to study the image quality of different images contrast-detail phantom CDMAM 3.4, carrying out the automatic detection of the contrast-detail combination and to establish a parameter which characterize in an objective way the mammographic image quality. This is useful to compare images obtained at different digital mammographic equipments to study the functioning of the equipments that facilitates the evaluation of image contrast and detail resolution.

  8. Enhancement of Mammographic Density Measures in Breast Cancer Risk Prediction

    PubMed Central

    Cheddad, Abbas; Czene, Kamila; Shepherd, John A.; Li, Jingmei; Hall, Per; Humphreys, Keith

    2016-01-01

    Background Mammographic density is a strong risk factor for breast cancer. Methods We present a novel approach to enhance area density measures that takes advantage of the relative density of the pectoral muscle that appears in lateral mammographic views. We hypothesized that the grey scale of film mammograms is normalized to volume breast density but not pectoral density and thus pectoral density becomes an independent marker of volumetric density. Results From analysis of data from a Swedish case–control study (1,286 breast cancer cases and 1,391 control subjects, ages 50–75 years), we found that the mean intensity of the pectoral muscle (MIP) was highly associated with breast cancer risk [per SD: OR = 0.82; 95% confidence interval (CI), 0.75–0.88; P = 6 × 10−7] after adjusting for a validated computer-assisted measure of percent density (PD), Cumulus. The area under curve (AUC) changed from 0.600 to 0.618 due to using PD with the pectoral muscle as reference instead of a standard area-based PD measure. We showed that MIP is associated with a genetic variant known to be associated with mammographic density and breast cancer risk, rs10995190, in a subset of women with genetic data. We further replicated the association between MIP and rs10995190 in an additional cohort of 2,655 breast cancer cases (combined P = 0.0002). Conclusions MIP is a marker of volumetric density that can be used to complement area PD in mammographic density studies and breast cancer risk assessment. Impact Inclusion of MIP in risk models should be considered for studies using area PD from analog films. PMID:24722754

  9. Mammographic Breast Density in a Cohort of Medically Underserved Women

    DTIC Science & Technology

    2015-12-01

    newsletter (Appendix). Results of our diabetes and mammographic breast density manuscript indicated that after adjustment for confounding variables...the mean percent breast density among premenopausal women with type 2 diabetes ( ̂ 13.8%, 95% confidence interval [CI] 11.6-15.9) was non...significantly lower than that of women without type 2 diabetes ( ̂ 15.9%, 95% CI 15.0-16.8) (p=0.07); however, there was no association among

  10. Classification of mammographic microcalcifications using wavelets

    NASA Astrophysics Data System (ADS)

    Chitre, Yateen S.; Dhawan, Atam P.; Moskowitz, Myron; Sarwal, Alok; Bonasso, Christine; Narayan, Suresh B.

    1995-05-01

    Breast cancer is the leading cause of death among women. Breast cancer can be detected earlier by mammography than any other non-invasive examination. About 30% to 50% of breast cancers demonstrate tiny granulelike deposits of calcium called microcalcifications. It is difficult to distinguish between benign and malignant cases based on an examination of calcification regions, especially in hard-to-diagnose cases. We investigate the potential of using energy and entropy features computed from wavelet packets for their correlation with malignancy. Two types of Daubechies discrete filters were used as prototype wavelets. The energy and entropy features were computed for 128 benign and 63 malignant cases and analyzed using a multivariate cluster analysis and a univariate statistical analysis to reduce the feature set to a `five best set of features.' The efficacy of the reduced feature set to discriminate between the malignant and benign categories was evaluated using different multilayer perceptron architectures. The multilayer perceptron was trained using the backpropagation algorithm for various training and test set sizes. For each case 40 partitions of the data set were used to set up the training and test sets. The performance of the features was evaluated by computing the best area under the relative operating characteristic (ROC) curve and the average area under the ROC curve. The performance of the features computed from the wavelet packets was compared to a second set of features consisting of the wavelet packet features, image structure features and cluster features. The classification results are encouraging and indicate the potential of using features derived from wavelet packets in discriminating microcalcification regions into benign and malignant categories.

  11. Digital mammographic tumor classification using transfer learning from deep convolutional neural networks.

    PubMed

    Huynh, Benjamin Q; Li, Hui; Giger, Maryellen L

    2016-07-01

    Convolutional neural networks (CNNs) show potential for computer-aided diagnosis (CADx) by learning features directly from the image data instead of using analytically extracted features. However, CNNs are difficult to train from scratch for medical images due to small sample sizes and variations in tumor presentations. Instead, transfer learning can be used to extract tumor information from medical images via CNNs originally pretrained for nonmedical tasks, alleviating the need for large datasets. Our database includes 219 breast lesions (607 full-field digital mammographic images). We compared support vector machine classifiers based on the CNN-extracted image features and our prior computer-extracted tumor features in the task of distinguishing between benign and malignant breast lesions. Five-fold cross validation (by lesion) was conducted with the area under the receiver operating characteristic (ROC) curve as the performance metric. Results show that classifiers based on CNN-extracted features (with transfer learning) perform comparably to those using analytically extracted features [area under the ROC curve [Formula: see text

  12. A Qualitative Inquiry into the Complex Features of Strained Interactions: Analysis and Implications for Health Care Personnel

    PubMed Central

    Thunborg, Charlotta; Salzmann-Erikson, Martin

    2017-01-01

    Background Communication skills are vital for successful relationships between patients and health care professionals. Failure to communicate may lead to a lack of understanding and may result in strained interactions. Our theoretical point of departure was to make use of chaos and complexity theories. Objective To examine the features of strained interactions and to discuss their relevance for health care settings. Methods A netnography study design was applied. Data were purposefully sampled, and video clips (122 minutes from 30 video clips) from public online venues were used. Results The results are presented in four categories: 1) unpredictability, 2) sensitivity dependence, 3) resistibility, and 4) iteration. They are all features of strained interactions. Conclusion Strained interactions are a complex phenomenon that exists in health care settings. The findings provide health care professionals guidance to understand the complexity and the features of strained interactions. PMID:28368786

  13. Sex steroid metabolism polymorphisms and mammographic density in pre- and early perimenopausal women

    PubMed Central

    Crandall, Carolyn J; Sehl, Mary E; Crawford, Sybil L; Gold, Ellen B; Habel, Laurel A; Butler, Lesley M; Sowers, MaryFran R; Greendale, Gail A; Sinsheimer, Janet S

    2009-01-01

    Introduction We examined the association between mammographic density and single-nucleotide polymorphisms (SNPs) in genes encoding CYP1A1, CYP1B1, aromatase, 17β-HSD, ESR1, and ESR2 in pre- and early perimenopausal white, African-American, Chinese, and Japanese women. Methods The Study of Women's Health Across the Nation is a longitudinal community-based cohort study. We analyzed data from 451 pre- and early perimenopausal participants of the ancillary SWAN Mammographic Density study for whom we had complete information regarding mammographic density, genotypes, and covariates. With multivariate linear regression, we examined the relation between percentage mammographic breast density (outcome) and each SNP (primary predictor), adjusting for age, race/ethnicity, parity, cigarette smoking, and body mass index (BMI). Results After multivariate adjustment, the CYP1B1 rs162555 CC genotype was associated with a 9.4% higher mammographic density than the TC/TT genotype (P = 0.04). The CYP19A1 rs936306 TT genotype was associated with 6.2% lower mammographic density than the TC/CC genotype (P = 0.02). The positive association between CYP1A1 rs2606345 and mammographic density was significantly stronger among participants with BMI greater than 30 kg/m2 than among those with BMI less than 25 kg/m2 (Pinteraction = 0.05). Among white participants, the ESR1 rs2234693 CC genotype was associated with a 7.0% higher mammographic density than the CT/TT genotype (P = 0.01). Conclusions SNPs in certain genes encoding sex steroid metabolism enzymes and ESRs were associated with mammographic density. Because the encoded enzymes and ESR1 are expressed in breast tissue, these SNPs may influence breast cancer risk by altering mammographic density. PMID:19630952

  14. Grid-enabled mammographic auditing and training system

    NASA Astrophysics Data System (ADS)

    Yap, M. H.; Gale, A. G.

    2008-03-01

    Effective use of new technologies to support healthcare initiatives is important and current research is moving towards implementing secure grid-enabled healthcare provision. In the UK, a large-scale collaborative research project (GIMI: Generic Infrastructures for Medical Informatics), which is concerned with the development of a secure IT infrastructure to support very widespread medical research across the country, is underway. In the UK, there are some 109 breast screening centers and a growing number of individuals (circa 650) nationally performing approximately 1.5 million screening examinations per year. At the same, there is a serious, and ongoing, national workforce issue in screening which has seen a loss of consultant mammographers and a growth in specially trained technologists and other non-radiologists. Thus there is a need to offer effective and efficient mammographic training so as to maintain high levels of screening skills. Consequently, a grid based system has been proposed which has the benefit of offering very large volumes of training cases that the mammographers can access anytime and anywhere. A database, spread geographically across three university systems, of screening cases is used as a test set of known cases. The GIMI mammography training system first audits these cases to ensure that they are appropriately described and annotated. Subsequently, the cases are utilized for training in a grid-based system which has been developed. This paper briefly reviews the background to the project and then details the ongoing research. In conclusion, we discuss the contributions, limitations, and future plans of such a grid based approach.

  15. Adolescent intake of animal fat and red meat in relation to premenopausal mammographic density.

    PubMed

    Bertrand, Kimberly A; Burian, Rosemarie A; Eliassen, A Heather; Willett, Walter C; Tamimi, Rulla M

    2016-01-01

    Adolescence is hypothesized to be a time period of particular susceptibility to breast cancer risk factors. Red meat and fat intake during high school was positively associated with risk of breast cancer among premenopausal women in the Nurses' Health Study II (NHSII). High mammographic density is a strong predictor of breast cancer risk but there is limited research on dietary factors associated with breast density. To test the hypothesis that high intake of animal fat or red meat during adolescence is associated with mammographic density, we analyzed data from premenopausal women in the NHSII. Participants recalled adolescent diet on a high school food frequency questionnaire. We assessed absolute and percent mammographic density on digitized analog film mammograms for 687 premenopausal women with no history of cancer. We used generalized linear regression to quantify associations of adolescent animal fat and red meat intake with mammographic density, adjusting for age, body mass index, and other predictors of mammographic density. Adolescent animal fat intake was significantly positively associated with premenopausal mammographic density, with a mean percent density of 39.2 % in the lowest quartile of adolescent animal fat intake versus 43.1 % in the highest quartile (p trend: 0.03). A non-significant positive association was also observed for adolescent red meat intake (p trend: 0.14). These findings suggest that higher adolescent animal fat intake is weakly associated with percent mammographic density in premenopausal women.

  16. Cyclic endogenous estrogen and progesterone vary by mammographic density phenotypes in premenopausal women

    PubMed Central

    Iversen, Anita; Furberg, Anne-Sofie; Flote, Vidar G.; Finstad, Sissi Espetvedt; McTiernan, Anne; Ursin, Giske; Wilsgaard, Tom; Ellison, Peter T.; Jasienska, Grazyna; Thune, Inger

    2016-01-01

    Estrogen and progesterone are key factors in the development of breast cancer, but it remains unclear whether these hormones are associated with mammographic density phenotypes in premenopausal women. We measured percent mammographic density, nondense area, and absolute mammographic density using computer-assisted breast density readings (Madena) from digitized mammograms taken on a scheduled day of the menstrual cycle (day 7–12) among 202 healthy, premenopausal women (Energy Balance and Breast cancer Aspects Study-I). Daily salivary concentrations of 17β-estradiol and progesterone throughout an entire menstrual cycle and fasting morning serum concentrations of hormones on 3 specific days of the menstrual cycle were assessed. Salivary and serum 17β-estradiol and progesterone were positively associated with percent mammographic density, we observed by 1 SD increase in overall salivary estradiol (β-value equal to 2.07, P=0.044), luteal salivary progesterone (β-value equal to 2.40, P=0.020). Women with above-median percent mammographic density had a 20% higher mean salivary 17β-estradiol level throughout the menstrual cycle. The odds ratio for having above-median percent mammographic density (>28.5%) per 1 SD increase in overall salivary 17β-estradiol was 1.66 (95% confidence interval 1.13–2.45). Women in the top tertile of the overall average daily 17β-estradiol concentrations had an odds ratio of 2.54 (confidence interval 1.05–6.16) of above-median percent mammographic density compared with women in the bottom tertile. Our finding of a relationship between estrogen, progesterone, and percent mammographic density and not with other mammographic density phenotypes in premenopausal women is biologically plausible, but needs to be replicated in larger studies. PMID:25714648

  17. Classification of mammographic masses: comparison between Backpropagation Neural Network (BNN) and human readers

    NASA Astrophysics Data System (ADS)

    Arbach, Lina; Bennett, Darus L.; Reinhardt, Joseph M.; Fallouh, Ghassan

    2003-05-01

    PURPOSE: We compare mammographic mass classification performance between a backpropagation neural network (BNN), expert radiologists, and residents. Our goal is to reduce false negatives during routine reading of mammograms. METHODS: 160 cases from 3 different institutions were used. Each case contained at least one mass and had an accompanying biopsy result. Masses were extracted using region growing with seed locations identified by an expert radiologist. 10 texture and shape based features (area, perimeter, compactness, radial length, spiculation, mean/standard deviation of radial length, minimum/maximum axis, and boundary roughness) were used as inputs to a three-layer BNN. Shape features were computed on the boundary of the mass region; texture features were computed from the pixel values inside the mass. 140 cases were used for training the BNN and the remaining 20 cases were used for testing. The testing set was diagnosed by three expert radiologists, three residents, and the BNN. We evaluated the human readers and the BNN by computing the area under the ROC curve (AUC). RESULTS: The AUC was 0.923 for the BNN, 0.846 for the expert radiologists, and 0.648 for the residents. These results illustrate the promise of using BNN as a physician"s assistant for breast mass classification.

  18. Evaluation of a new mammographic film: methods and considerations.

    PubMed

    Tsalafoutas, Oannis A; Kolovos, Christos A; Tsapaki, Virginia; Betsou, Sofia; Koliakou, Eleni; Maniatis, Petros N; Xenofos, Stelios

    2008-04-01

    In this study the performance of a new mammographic film, the XMA (Retina), was evaluated in comparison with HT (Agfa). The comparison was made in terms of sensitometric characteristics and in terms of image quality and speed when combined with four different cassettes-HDS (Agfa), Min-R 2000 and Min-R 2190 (Kodak), and AD-MA (Fuji)-using the Leeds TOR(MAX) Mammographic Quality Control phantom. The entrance surface air kerma was calculated from exposure factors and the relative speed of each screen-film combination was determined. These tests revealed that XMA requires about 40% less dose than HT when combined with the same intensifying screen, at a penalty of less than 8% in image quality. When combined with AD-MA the XMA presents the greatest speed, whereas the Min-R 2190 is the best compromise between image quality and breast dose. The above values are indicative of the dilemma that medical physicists and radiologists face when it comes to the selection of a screen-film combination for mammography. Both image quality and breast dose should be considered, but strict instructions on what weight should be assigned to each parameter have not been established yet. Health Phys. 94(4):338-344; 2008.

  19. Computerized quantitative evaluation of mammographic accreditation phantom images

    SciTech Connect

    Lee, Yongbum; Tsai, Du-Yih; Shinohara, Norimitsu

    2010-12-15

    Purpose: The objective was to develop and investigate an automated scoring scheme of the American College of Radiology (ACR) mammographic accreditation phantom (RMI 156, Middleton, WI) images. Methods: The developed method consisted of background subtraction, determination of region of interest, classification of fiber and mass objects by Mahalanobis distance, detection of specks by template matching, and rule-based scoring. Fifty-one phantom images were collected from 51 facilities for this study (one facility provided one image). A medical physicist and two radiologic technologists also scored the images. The human and computerized scores were compared. Results: In terms of meeting the ACR's criteria, the accuracies of the developed method for computerized evaluation of fiber, mass, and speck were 90%, 80%, and 98%, respectively. Contingency table analysis revealed significant association between observer and computer scores for microcalcifications (p<5%) but not for masses and fibers. Conclusions: The developed method may achieve a stable assessment of visibility for test objects in mammographic accreditation phantom image in whether the phantom image meets the ACR's criteria in the evaluation test, although there is room left for improvement in the approach for fiber and mass objects.

  20. Evaluation of four mammographic density measures on HRT data

    NASA Astrophysics Data System (ADS)

    Raundahl, Jakob; Loog, Marco; Pettersen, Paola; Nielsen, Mads

    2007-03-01

    Numerous studies have investigated the relation between mammographic density and breast cancer risk. These studies indicate that women with dense breasts have a four to six fold risk increase. There is currently no gold standard for automatic assessment of mammographic density. In previous work two different automated methods for measuring the effect of HRT w.r.t. changes in breast density have been presented. One is a percentage density based on an adaptive global threshold, and the other is an intensity invariant measure, which provides structural information orthogonal to intensity-based methods. In this article we investigate the ability to detect density changes induced by HRT for these measures and compare to a radiologist's BI-RADS rating and interactive threshold percentage density. In the experiments, two sets of mammograms of 80 patients from a double blind, placebo controlled HRT experiment are used. The p-values for the statistical significance of the separation of density means, for the HRT group and the placebo group at end of study, are 0.2, 0.1, 0.02 and 0.02 for the automatic threshold, BI-RADS, the stripyness and the interactive threshold respectively.

  1. Mammographic resolution: influence of focal spot intensity distribution and geometry.

    PubMed

    Nickoloff, E L; Donnelly, E; Eve, L; Atherton, J V; Asch, T

    1990-01-01

    The influence of focal spot intensity distribution and geometry upon mammographic image quality were evaluated. The modulation transfer functions (MTF's) for eight different intensity distributions were determined and plotted in a manner to eliminate the effects of magnification and focal spot dimension. The results indicated that the total cross-sectional area is important for focal spots with uniform intensity distributions and equivalent diameters. For equivalent focal spot dimensions, intensity distributions with edge bands were shown to have less spatial resolution than uniform intensity distributions. Focal spots with greater intensities towards their centers provided better resolution than either uniform intensity distributions or distributions with edge bands for equivalent sizes. The type of intensity distribution was also shown to affect the accuracy of star pattern measurements of focal spot size; this method of measurement is only precise for a uniform square intensity distribution. Errors obtained with several other intensity distributions were tabulated. The variations of the effective focal spot size with position along the anode-cathode axis were shown to be of a factor of approximately two to three. The combined effects of geometric blur and film/screen blur were present for various heights above the cassette tray on several different mammographic systems.

  2. Hyperspectral analysis for qualitative and quantitative features related to acid mine drainage at a remediated open-pit mine

    NASA Astrophysics Data System (ADS)

    Davies, G.; Calvin, W. M.

    2015-12-01

    The exposure of pyrite to oxygen and water in mine waste environments is known to generate acidity and the accumulation of secondary iron minerals. Sulfates and secondary iron minerals associated with acid mine drainage (AMD) exhibit diverse spectral properties in the ultraviolet, visible and near-infrared regions of the electromagnetic spectrum. The use of hyperspectral imagery for identification of AMD mineralogy and contamination has been well studied. Fewer studies have examined the impacts of hydrologic variations on mapping AMD or the unique spectral signatures of mine waters. Open-pit mine lakes are an additional environmental hazard which have not been widely studied using imaging spectroscopy. A better understanding of AMD variation related to climate fluctuations and the spectral signatures of contaminated surface waters will aid future assessments of environmental contamination. This study examined the ability of multi-season airborne hyperspectral data to identify the geochemical evolution of substances and contaminant patterns at the Leviathan Mine Superfund site. The mine is located 24 miles southeast of Lake Tahoe and contains remnant tailings piles and several AMD collection ponds. The objectives were to 1) distinguish temporal changes in mineralogy at a the remediated open-pit sulfur mine, 2) identify the absorption features of mine affected waters, and 3) quantitatively link water spectra to known dissolved iron concentrations. Images from NASA's AVIRIS instrument were collected in the spring, summer, and fall seasons for two consecutive years at Leviathan (HyspIRI campaign). Images had a spatial resolution of 15 meters at nadir. Ground-based surveys using the ASD FieldSpecPro spectrometer and laboratory spectral and chemical analysis complemented the remote sensing data. Temporal changes in surface mineralogy were difficult to distinguish. However, seasonal changes in pond water quality were identified. Dissolved ferric iron and chlorophyll

  3. Evaluation of mammographic density patterns: reproducibility and concordance among scales

    PubMed Central

    2010-01-01

    Background Increased mammographic breast density is a moderate risk factor for breast cancer. Different scales have been proposed for classifying mammographic density. This study sought to assess intra-rater agreement for the most widely used scales (Wolfe, Tabár, BI-RADS and Boyd) and compare them in terms of classifying mammograms as high- or low-density. Methods The study covered 3572 mammograms drawn from women included in the DDM-Spain study, carried-out in seven Spanish Autonomous Regions. Each mammogram was read by an expert radiologist and classified using the Wolfe, Tabár, BI-RADS and Boyd scales. In addition, 375 mammograms randomly selected were read a second time to estimate intra-rater agreement for each scale using the kappa statistic. Owing to the ordinal nature of the scales, weighted kappa was computed. The entire set of mammograms (3572) was used to calculate agreement among the different scales in classifying high/low-density patterns, with the kappa statistic being computed on a pair-wise basis. High density was defined as follows: percentage of dense tissue greater than 50% for the Boyd, "heterogeneously dense and extremely dense" categories for the BI-RADS, categories P2 and DY for the Wolfe, and categories IV and V for the Tabár scales. Results There was good agreement between the first and second reading, with weighted kappa values of 0.84 for Wolfe, 0.71 for Tabár, 0.90 for BI-RADS, and 0.92 for Boyd scale. Furthermore, there was substantial agreement among the different scales in classifying high- versus low-density patterns. Agreement was almost perfect between the quantitative scales, Boyd and BI-RADS, and good for those based on the observed pattern, i.e., Tabár and Wolfe (kappa 0.81). Agreement was lower when comparing a pattern-based (Wolfe or Tabár) versus a quantitative-based (BI-RADS or Boyd) scale. Moreover, the Wolfe and Tabár scales classified more mammograms in the high-risk group, 46.61 and 37.32% respectively, while

  4. Relationship of serum estrogens and metabolites with area and volume mammographic densities.

    PubMed

    Gierach, Gretchen L; Patel, Deesha A; Falk, Roni T; Pfeiffer, Ruth M; Geller, Berta M; Vacek, Pamela M; Weaver, Donald L; Chicoine, Rachael E; Shepherd, John A; Mahmoudzadeh, Amir Pasha; Wang, Jeff; Fan, Bo; Herschorn, Sally D; Xu, Xia; Veenstra, Timothy; Fuhrman, Barbara; Sherman, Mark E; Brinton, Louise A

    2015-06-01

    Elevated mammographic density is a breast cancer risk factor, which has a suggestive, but unproven, relationship with increased exposure to sex steroid hormones. We examined associations of serum estrogens and estrogen metabolites with area and novel volume mammographic density measures among 187 women, ages 40-65, undergoing diagnostic breast biopsies at an academic facility in Vermont. Serum parent estrogens, estrone and estradiol, and their 2-, 4-, and 16-hydroxylated metabolites were measured using liquid chromatography-tandem mass spectrometry. Area mammographic density was measured in the breast contralateral to the biopsy using thresholding software; volume mammographic density was quantified using a density phantom. Linear regression was used to estimate associations of estrogens with mammographic densities, adjusted for age and body mass index, and stratified by menopausal status and menstrual cycle phase. Weak, positive associations between estrogens, estrogen metabolites, and mammographic density were observed, primarily among postmenopausal women. Among premenopausal luteal phase women, the 16-pathway metabolite estriol was associated with percent area (p = 0.04) and volume (p = 0.05) mammographic densities and absolute area (p = 0.02) and volume (p = 0.05) densities. Among postmenopausal women, levels of total estrogens, the sum of parent estrogens, and 2-, 4- and 16-hydroxylation pathway metabolites were positively associated with area density measures (percent: p = 0.03, p = 0.04, p = 0.01, p = 0.02, p = 0.07; absolute: p = 0.02, p = 0.02, p = 0.01, p = 0.02, p = 0.03, respectively) but not volume density measures. Our data suggest that serum estrogen profiles are weak determinants of mammographic density and that analysis of different density metrics may provide complementary information about relationships of estrogen exposure to breast tissue composition.

  5. Relationship of Serum Estrogens and Metabolites with Area and Volume Mammographic Densities

    PubMed Central

    Gierach, Gretchen L.; Patel, Deesha A.; Falk, Roni T.; Pfeiffer, Ruth M.; Geller, Berta M.; Vacek, Pamela M.; Weaver, Donald L.; Chicoine, Rachael E.; Shepherd, John A.; Mahmoudzadeh, Amir Pasha; Wang, Jeff; Fan, Bo; Herschorn, Sally D.; Xu, Xia; Veenstra, Timothy; Fuhrman, Barbara; Sherman, Mark E.; Brinton, Louise A.

    2015-01-01

    Purpose Elevated mammographic density is a breast cancer risk factor, which has a suggestive, but unproven, relationship with increased exposure to sex-steroid hormones. We examined associations of serum estrogens and estrogen metabolites with area and novel volume mammographic density measures among 187 women, ages 40–65, undergoing diagnostic breast biopsies at an academic facility in Vermont. Methods Serum parent estrogens, estrone and estradiol, and their 2-, 4-, and 16-hydroxylated metabolites were measured using liquid chromatography-tandem mass spectrometry. Area mammographic density was measured in the breast contralateral to the biopsy using thresholding software; volume mammographic density was quantified using a density phantom. Linear regression was used to estimate associations of estrogens with mammographic densities, adjusted for age and body mass index, and stratified by menopausal status and menstrual cycle phase. Results Weak, positive associations between estrogens, estrogen metabolites and mammographic density were observed, primarily among postmenopausal women. Among premenopausal luteal phase women, the 16-pathway metabolite estriol was associated with percent area (p=0.04) and volume (p=0.05) mammographic densities and absolute area (p=0.02) and volume (p=0.05) densities. Among postmenopausal women, levels of total estrogens, the sum of parent estrogens, and 2-, 4- and 16-hydroxylation pathway metabolites were positively associated with area density measures (percent: p=0.03, p=0.04, p=0.01, p=0.02, p=0.07; absolute: p=0.02, p=0.02, p=0.01, p=0.02, p=0.03, respectively), but not volume density measures. Conclusions Our data suggest that serum estrogen profiles are weak determinants of mammographic density and that analysis of different density metrics may provide complementary information about relationships of exposures to breast tissue composition. PMID:25757805

  6. Common variants in ZNF365 are associated with both mammographic density and breast cancer risk.

    PubMed

    Lindström, Sara; Vachon, Celine M; Li, Jingmei; Varghese, Jajini; Thompson, Deborah; Warren, Ruth; Brown, Judith; Leyland, Jean; Audley, Tina; Wareham, Nicholas J; Loos, Ruth J F; Paterson, Andrew D; Rommens, Johanna; Waggott, Darryl; Martin, Lisa J; Scott, Christopher G; Pankratz, V Shane; Hankinson, Susan E; Hazra, Aditi; Hunter, David J; Hopper, John L; Southey, Melissa C; Chanock, Stephen J; Silva, Isabel dos Santos; Liu, JianJun; Eriksson, Louise; Couch, Fergus J; Stone, Jennifer; Apicella, Carmel; Czene, Kamila; Kraft, Peter; Hall, Per; Easton, Douglas F; Boyd, Norman F; Tamimi, Rulla M

    2011-03-01

    High-percent mammographic density adjusted for age and body mass index is one of the strongest risk factors for breast cancer. We conducted a meta analysis of five genome-wide association studies of percent mammographic density and report an association with rs10995190 in ZNF365 (combined P = 9.6 × 10(-10)). Common variants in ZNF365 have also recently been associated with susceptibility to breast cancer.

  7. Developing a new case based computer-aided detection scheme and an adaptive cueing method to improve performance in detecting mammographic lesions

    NASA Astrophysics Data System (ADS)

    Tan, Maxine; Aghaei, Faranak; Wang, Yunzhi; Zheng, Bin

    2017-01-01

    The purpose of this study is to evaluate a new method to improve performance of computer-aided detection (CAD) schemes of screening mammograms with two approaches. In the first approach, we developed a new case based CAD scheme using a set of optimally selected global mammographic density, texture, spiculation, and structural similarity features computed from all four full-field digital mammography images of the craniocaudal (CC) and mediolateral oblique (MLO) views by using a modified fast and accurate sequential floating forward selection feature selection algorithm. Selected features were then applied to a ‘scoring fusion’ artificial neural network classification scheme to produce a final case based risk score. In the second approach, we combined the case based risk score with the conventional lesion based scores of a conventional lesion based CAD scheme using a new adaptive cueing method that is integrated with the case based risk scores. We evaluated our methods using a ten-fold cross-validation scheme on 924 cases (476 cancer and 448 recalled or negative), whereby each case had all four images from the CC and MLO views. The area under the receiver operating characteristic curve was AUC  =  0.793  ±  0.015 and the odds ratio monotonically increased from 1 to 37.21 as CAD-generated case based detection scores increased. Using the new adaptive cueing method, the region based and case based sensitivities of the conventional CAD scheme at a false positive rate of 0.71 per image increased by 2.4% and 0.8%, respectively. The study demonstrated that supplementary information can be derived by computing global mammographic density image features to improve CAD-cueing performance on the suspicious mammographic lesions.

  8. Computer-aided classification of mammographic masses using the deep learning technology: a preliminary study

    NASA Astrophysics Data System (ADS)

    Qiu, Yuchen; Yan, Shiju; Tan, Maxine; Cheng, Samuel; Liu, Hong; Zheng, Bin

    2016-03-01

    Although mammography is the only clinically acceptable imaging modality used in the population-based breast cancer screening, its efficacy is quite controversy. One of the major challenges is how to help radiologists more accurately classify between benign and malignant lesions. The purpose of this study is to investigate a new mammographic mass classification scheme based on a deep learning method. In this study, we used an image dataset involving 560 regions of interest (ROIs) extracted from digital mammograms, which includes 280 malignant and 280 benign mass ROIs, respectively. An eight layer deep learning network was applied, which employs three pairs of convolution-max-pooling layers for automatic feature extraction and a multiple layer perception (MLP) classifier for feature categorization. In order to improve robustness of selected features, each convolution layer is connected with a max-pooling layer. A number of 20, 10, and 5 feature maps were utilized for the 1st, 2nd and 3rd convolution layer, respectively. The convolution networks are followed by a MLP classifier, which generates a classification score to predict likelihood of a ROI depicting a malignant mass. Among 560 ROIs, 420 ROIs were used as a training dataset and the remaining 140 ROIs were used as a validation dataset. The result shows that the new deep learning based classifier yielded an area under the receiver operation characteristic curve (AUC) of 0.810+/-0.036. This study demonstrated the potential superiority of using a deep learning based classifier to distinguish malignant and benign breast masses without segmenting the lesions and extracting the pre-defined image features.

  9. Computerized analysis of mammographic parenchymal patterns using fractal analysis

    NASA Astrophysics Data System (ADS)

    Li, Hui; Giger, Maryellen L.; Huo, Zhimin; Olopade, Olufunmilayo I.; Chinander, Michael R.; Lan, Li; Bonta, Ioana R.

    2003-05-01

    Mammographic parenchymal patterns have been shown to be associated with breast cancer risk. Fractal-based texture analyses, including box-counting methods and Minkowski dimension, were performed within parenchymal regions of normal mammograms of BRCA1/BRCA2 gene mutation carriers and within those of women at low risk for developing breast cancer. Receiver Operating Characteristic (ROC) analysis was used to assess the performance of the computerized radiographic markers in the task of distinguishing between high and low-risk subjects. A multifractal phenomenon was observed with the fractal analyses. The high frequency component of fractal dimension from the conventional box-counting technique yielded an Az value of 0.84 in differentiating between two groups, while using the LDA to estimate the fractal dimension yielded an Az value of 0.91 for the high frequency component. An Az value of 0.82 was obtained with fractal dimensions extracted using the Minkowski algorithm.

  10. Statistical Segmentation of Regions of Interest on a Mammographic Image

    NASA Astrophysics Data System (ADS)

    Adel, Mouloud; Rasigni, Monique; Bourennane, Salah; Juhan, Valerie

    2007-12-01

    This paper deals with segmentation of breast anatomical regions, pectoral muscle, fatty and fibroglandular regions, using a Bayesian approach. This work is a part of a computer aided diagnosis project aiming at evaluating breast cancer risk and its association with characteristics (density, texture, etc.) of regions of interest on digitized mammograms. Novelty in this paper consists in applying and adapting Markov random field for detecting breast anatomical regions on digitized mammograms whereas most of previous works were focused on masses and microcalcifications. The developed method was tested on 50 digitized mammograms of the mini-MIAS database. Computer segmentation is compared to manual one made by a radiologist. A good agreement is obtained on 68% of the mini-MIAS mammographic image database used in this study. Given obtained segmentation results, the proposed method could be considered as a satisfying first approach for segmenting regions of interest in a breast.

  11. Metabolic syndrome and mammographic density in Mexican women.

    PubMed

    Rice, Megan S; Biessy, Carine; Lajous, Martin; Bertrand, Kimberly A; Tamimi, Rulla M; Torres-Mejía, Gabriela; López-Ridaura, Ruy; Romieu, Isabelle

    2013-07-01

    Metabolic syndrome has been associated with an increased risk of breast cancer; however, little is known about the association between metabolic syndrome and percent mammographic density, a strong predictor of breast cancer. We analyzed cross-sectional data from 789 premenopausal and 322 postmenopausal women in the Mexican Teacher's Cohort (ESMaestras). Metabolic syndrome was defined according to the harmonized definition. We measured percent density on mammograms using a computer-assisted thresholding method. Multivariable linear regression was used to estimate the association between density and metabolic syndrome, as well as its components by state (Jalisco, Veracruz) and menopausal status (premenopausal, postmenopausal). Among premenopausal women in Jalisco, women with metabolic syndrome had higher percent density than those without after adjusting for potential confounders including BMI [difference = 4.76; 95% confidence interval (CI), 1.72-7.81]. Among the metabolic syndrome components, only low high-density lipoprotein levels (<50 mg/dL) were associated with significantly higher percent density among premenopausal women in Jalisco (difference = 4.62; 95% CI, 1.73-7.52). Metabolic syndrome was not associated with percent density among premenopausal women in Veracruz (difference = -2.91; 95% CI, -7.19 to 1.38), nor among postmenopausal women in either state. Metabolic syndrome was associated with higher percent density among premenopausal women in Jalisco, Mexico, but was not associated with percent density among premenopausal women in Veracruz, Mexico, or among postmenopausal women in either Jalisco or Veracruz. These findings provide some support for a possible role of metabolic syndrome in mammographic density among premenopausal women; however, results were inconsistent across states and require further confirmation in larger studies.

  12. An Investigation into the Consistency in Mammographic Density Identification by Radiologists: Effect of Radiologist Expertise and Mammographic Appearance.

    PubMed

    Li, Yanpeng; Brennan, Patrick C; Lee, Warwick; Nickson, Carolyn; Pietrzyk, Mariusz W; Ryan, Elaine A

    2015-10-01

    The aim of this work is to investigate how radiologist expertise and image appearance may have an impact on inter-reader variability of mammographic density (MD) identification. Seventeen radiologists, divided into three expertise groups, were asked to manually segment the areas they consider to be MD in 40 clinical images. The variation in identification of MD for each image was quantified by finding the range of segmentation areas. The impact of radiologist expertise and image appearance on this variation was explored. The range of areas chosen by participating radiologists varied from 7 to 73% across the 40 images, with a mean range of 35 ± 13%. Participants with high expertise were more likely to choose similar areas to one another, compared to participants with medium and low expertise levels (mean range were 19 ± 10%, 29 ± 13% and 25 ± 14 %, respectively, p < 0.0001). There was a significantly higher average grey level for the area segmented by all radiologists as MD compared to the area of variation, with mean grey level value for 8-bit images being 146 ± 19 vs. 99 ± 14, respectively. MD segmentation borders were consistent in areas where there was a sharp intensity change within a short distance. In conclusion, radiologists with high expertise tend to have a higher agreement when identifying MD. Tissues which have a lower contrast and a less visually sharp gradient change at the interface between high density tissue and adipose background lead to inter-reader variation in choosing mammographic density.

  13. Predictive modeling of human perception subjectivity: feasibility study of mammographic lesion similarity

    NASA Astrophysics Data System (ADS)

    Xu, Songhua; Hudson, Kathleen; Bradley, Yong; Daley, Brian J.; Frederick-Dyer, Katherine; Tourassi, Georgia

    2012-02-01

    The majority of clinical content-based image retrieval (CBIR) studies disregard human perception subjectivity, aiming to duplicate the consensus expert assessment of the visual similarity on example cases. The purpose of our study is twofold: i) discern better the extent of human perception subjectivity when assessing the visual similarity of two images with similar semantic content, and (ii) explore the feasibility of personalized predictive modeling of visual similarity. We conducted a human observer study in which five observers of various expertise were shown ninety-nine triplets of mammographic masses with similar BI-RADS descriptors and were asked to select the two masses with the highest visual relevance. Pairwise agreement ranged between poor and fair among the five observers, as assessed by the kappa statistic. The observers' self-consistency rate was remarkably low, based on repeated questions where either the orientation or the presentation order of a mass was changed. Various machine learning algorithms were explored to determine whether they can predict each observer's personalized selection using textural features. Many algorithms performed with accuracy that exceeded each observer's self-consistency rate, as determined using a cross-validation scheme. This accuracy was statistically significantly higher than would be expected by chance alone (two-tailed p-value ranged between 0.001 and 0.01 for all five personalized models). The study confirmed that human perception subjectivity should be taken into account when developing CBIR-based medical applications.

  14. Predictive Modeling of Human Perception Subjectivity: Feasibility Study of Mammographic Lesion Similarity

    SciTech Connect

    Xu, Songhua; Tourassi, Georgia

    2012-01-01

    The majority of clinical content-based image retrieval (CBIR) studies disregard human perception subjectivity, aiming to duplicate the consensus expert assessment of the visual similarity on example cases. The purpose of our study is twofold: (i) discern better the extent of human perception subjectivity when assessing the visual similarity of two images with similar semantic content, and (ii) explore the feasibility of personalized predictive modeling of visual similarity. We conducted a human observer study in which five observers of various expertise were shown ninety-nine triplets of mammographic masses with similar BI-RADS descriptors and were asked to select the two masses with the highest visual relevance. Pairwise agreement ranged between poor and fair among the five observers, as assessed by the kappa statistic. The observers' self-consistency rate was remarkably low, based on repeated questions where either the orientation or the presentation order of a mass was changed. Various machine learning algorithms were explored to determine whether they can predict each observer's personalized selection using textural features. Many algorithms performed with accuracy that exceeded each observer's self-consistency rate, as determined using a cross-validation scheme. This accuracy was statistically significantly higher than would be expected by chance alone (two-tailed p-value ranged between 0.001 and 0.01 for all five personalized models). The study confirmed that human perception subjectivity should be taken into account when developing CBIR-based medical applications.

  15. Paget disease of the breast: mammographic, US, and MR imaging findings with pathologic correlation.

    PubMed

    Lim, Hyo Soon; Jeong, Su Jin; Lee, Ji Shin; Park, Min Ho; Kim, Jin Woong; Shin, Sang Soo; Park, Jin Gyoon; Kang, Heoung Keun

    2011-01-01

    Paget disease is a rare malignancy of the breast characterized by infiltration of the nipple epidermis by adenocarcinoma cells. The clinical features of Paget disease are characteristic and should increase the likelihood of the diagnosis being made. An important point is that more than 90% of cases of Paget disease are associated with an additional underlying breast malignancy. Paget disease is frequently associated with ductal carcinoma in situ (DCIS) in the underlying lactiferous ducts of the nipple-areolar complex; it may even be associated with DCIS or invasive breast cancer elsewhere in the breast, at least 2 cm from the nipple-areolar complex. Nevertheless, mammographic findings may be negative in up to 50% of cases. Magnetic resonance (MR) imaging can be useful in patients with Paget disease for evaluation of the nipple-areolar complex and identification of an additional underlying malignancy in the breast. The appropriate surgical treatment must be carefully selected and individualized on the basis of radiologic findings, especially those obtained with breast MR imaging.

  16. The relative effect of mammographic screening on breast cancer mortality by socioeconomic status.

    PubMed

    Ripping, Theodora M; van der Waal, Danielle; Verbeek, André L M; Broeders, Mireille J M

    2016-08-01

    Breast cancer incidence and mortality are higher in women with a high socioeconomic status (SES). The potential to prevent death from breast cancer is therefore greater in the high SES group. This does, however, require that the effectiveness of screening in the high SES group is equal to or greater than the effectiveness in the low SES group. The aim of this study is to assess the relative effectiveness of mammographic screening on breast cancer mortality by SES.In Nijmegen, the Netherlands, women are invited to participate in biennial mammographic screening since 1975. Postal code is collected at each round and is used to calculate the SES of each woman based on the SES indicator of the Netherlands Institute for Social Research. The Dutch average was used to classify the SES score of each woman as either high or low. We designed a case-control study to investigate the effect of mammographic screening in women aged 50 to 75, 40 to 75, and 50 to 69 years, and calculated the odds ratios (ORs) and 95% confidence intervals (CIs).Among the women invited to the mammographic screening program in Nijmegen, 10% had a high SES. In women aged 50 to 75 years, the breast cancer death rate was 38% lower in screened women than in unscreened women. The ORs for women with high SES (OR 0.82, 95% CI 0.31-2.19) and low SES did not differ significantly (OR 0.61, 95% CI 0.47-0.78).Mammographic screening reduces breast cancer mortality, but we did not observe a significant difference in the relative effectiveness of screening by SES. If the effectiveness of mammographic screening is indeed not dependent on SES status, the absolute number of breast cancer deaths prevented by mammographic screening will be greater in the high SES than low SES group, because women with a high SES have a greater risk of breast cancer death.

  17. Association between mammographic density and basal-like and luminal A breast cancer subtypes

    PubMed Central

    2013-01-01

    Introduction Mammographic density is a strong risk factor for breast cancer overall, but few studies have examined the association between mammographic density and specific subtypes of breast cancer, especially aggressive basal-like breast cancers. Because basal-like breast cancers are less frequently screen-detected, it is important to understand how mammographic density relates to risk of basal-like breast cancer. Methods We estimated associations between mammographic density and breast cancer risk according to breast cancer subtype. Cases and controls were participants in the Carolina Breast Cancer Study (CBCS) who also had mammograms recorded in the Carolina Mammography Registry (CMR). A total of 491 cases had mammograms within five years prior to and one year after diagnosis and 528 controls had screening or diagnostic mammograms close to the dates of selection into CBCS. Mammographic density was reported to the CMR using Breast Imaging Reporting and Data System categories. The expression of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 1 and 2 (HER1 and HER2), and cytokeratin 5/6 (CK5/6) were assessed by immunohistochemistry and dichotomized as positive or negative, with ER+ and/or PR+, and HER2- tumors classified as luminal A and ER-, PR-, HER2-, HER1+ and/or CK5/6+ tumors classified as basal-like breast cancer. Triple negative tumors were defined as negative for ER, PR and HER2. Of the 491 cases 175 were missing information on subtypes; the remaining cases included 181 luminal A, 17 luminal B, 48 basal-like, 29 ER-/PR-/HER2+, and 41 unclassified subtypes. Odds ratios comparing each subtype to all controls and case-case odds ratios comparing mammographic density distributions in basal-like to luminal A breast cancers were estimated using logistic regression. Results Mammographic density was associated with increased risk of both luminal A and basal-like breast cancers, although estimates were imprecise. The

  18. Novel Associations between Common Breast Cancer Susceptibility Variants and Risk-Predicting Mammographic Density Measures.

    PubMed

    Stone, Jennifer; Thompson, Deborah J; Dos Santos Silva, Isabel; Scott, Christopher; Tamimi, Rulla M; Lindstrom, Sara; Kraft, Peter; Hazra, Aditi; Li, Jingmei; Eriksson, Louise; Czene, Kamila; Hall, Per; Jensen, Matt; Cunningham, Julie; Olson, Janet E; Purrington, Kristen; Couch, Fergus J; Brown, Judith; Leyland, Jean; Warren, Ruth M L; Luben, Robert N; Khaw, Kay-Tee; Smith, Paula; Wareham, Nicholas J; Jud, Sebastian M; Heusinger, Katharina; Beckmann, Matthias W; Douglas, Julie A; Shah, Kaanan P; Chan, Heang-Ping; Helvie, Mark A; Le Marchand, Loic; Kolonel, Laurence N; Woolcott, Christy; Maskarinec, Gertraud; Haiman, Christopher; Giles, Graham G; Baglietto, Laura; Krishnan, Kavitha; Southey, Melissa C; Apicella, Carmel; Andrulis, Irene L; Knight, Julia A; Ursin, Giske; Alnaes, Grethe I Grenaker; Kristensen, Vessela N; Borresen-Dale, Anne-Lise; Gram, Inger Torhild; Bolla, Manjeet K; Wang, Qin; Michailidou, Kyriaki; Dennis, Joe; Simard, Jacques; Pharoah, Paul; Dunning, Alison M; Easton, Douglas F; Fasching, Peter A; Pankratz, V Shane; Hopper, John L; Vachon, Celine M

    2015-06-15

    Mammographic density measures adjusted for age and body mass index (BMI) are heritable predictors of breast cancer risk, but few mammographic density-associated genetic variants have been identified. Using data for 10,727 women from two international consortia, we estimated associations between 77 common breast cancer susceptibility variants and absolute dense area, percent dense area and absolute nondense area adjusted for study, age, and BMI using mixed linear modeling. We found strong support for established associations between rs10995190 (in the region of ZNF365), rs2046210 (ESR1), and rs3817198 (LSP1) and adjusted absolute and percent dense areas (all P < 10(-5)). Of 41 recently discovered breast cancer susceptibility variants, associations were found between rs1432679 (EBF1), rs17817449 (MIR1972-2: FTO), rs12710696 (2p24.1), and rs3757318 (ESR1) and adjusted absolute and percent dense areas, respectively. There were associations between rs6001930 (MKL1) and both adjusted absolute dense and nondense areas, and between rs17356907 (NTN4) and adjusted absolute nondense area. Trends in all but two associations were consistent with those for breast cancer risk. Results suggested that 18% of breast cancer susceptibility variants were associated with at least one mammographic density measure. Genetic variants at multiple loci were associated with both breast cancer risk and the mammographic density measures. Further understanding of the underlying mechanisms at these loci could help identify etiologic pathways implicated in how mammographic density predicts breast cancer risk.

  19. Stress signaling from human mammary epithelial cells contributes to phenotypes of mammographic density.

    PubMed

    DeFilippis, Rosa Anna; Fordyce, Colleen; Patten, Kelley; Chang, Hang; Zhao, Jianxin; Fontenay, Gerald V; Kerlikowske, Karla; Parvin, Bahram; Tlsty, Thea D

    2014-09-15

    Telomere malfunction and other types of DNA damage induce an activin A-dependent stress response in mortal nontumorigenic human mammary epithelial cells that subsequently induces desmoplastic-like phenotypes in neighboring fibroblasts. Some characteristics of this fibroblast/stromal response, such as reduced adipocytes and increased extracellular matrix content, are observed not only in tumor tissues but also in disease-free breast tissues at high risk for developing cancer, especially high mammographic density tissues. We found that these phenotypes are induced by repression of the fatty acid translocase CD36, which is seen in desmoplastic and disease-free high mammographic density tissues. In this study, we show that epithelial cells from high mammographic density tissues have more DNA damage signaling, shorter telomeres, increased activin A secretion and an altered DNA damage response compared with epithelial cells from low mammographic density tissues. Strikingly, both telomere malfunction and activin A expression in epithelial cells can repress CD36 expression in adjacent fibroblasts. These results provide new insights into how high mammographic density arises and why it is associated with breast cancer risk, with implications for the definition of novel invention targets (e.g., activin A and CD36) to prevent breast cancer.

  20. Stress Signaling from Human Mammary Epithelial Cells Contributes to Phenotypes of Mammographic Density

    PubMed Central

    Patten, Kelley; Chang, Hang; Zhao, Jianxin; Fontenay, Gerald V.; Kerlikowske, Karla; Parvin, Bahram; Tlsty, Thea D.

    2014-01-01

    Telomere malfunction and other types of DNA damage induce an activin A-dependent stress response in mortal non-tumorigenic human mammary epithelial cells that subsequently induces desmoplastic-like phenotypes in neighboring fibroblasts. Some characteristics of this fibroblast/stromal response, such as reduced adipocytes and increased extracellular matrix content, are observed not only in tumor tissues but also in disease-free breast tissues at high risk for developing cancer, especially high mammographic density tissues. We found that these phenotypes are induced by repression of the fatty acid translocase CD36, which is seen in desmoplastic and disease-free high mammographic density tissues. In this study, we show that epithelial cells from high mammographic density tissues have more DNA damage signaling, shorter telomeres, increased activin A secretion and an altered DNA damage response compared to epithelial cells from low mammographic density tissues. Strikingly, both telomere malfunction and activin A expression in epithelial cells can repress CD36 expression in adjacent fibroblasts. These results provide new insights into how high mammographic density arises and why it is associated with breast cancer risk, with implications for the definition of novel invention targets (e.g. activin A, CD36) to prevent breast cancer. PMID:25172842

  1. Hormone metabolism genes and mammographic density in Singapore Chinese women

    PubMed Central

    Lee, Eunjung; Su, Yu-Chen; Lewinger, Juan Pablo; Hsu, Chris; Van den Berg, David; Ursin, Giske; Koh, Woon-Puay; Yuan, Jian-Min; Stram, Daniel O.; Yu, Mimi C.; Wu, Anna H.

    2014-01-01

    Background Female steroid hormone levels and exogenous hormone use influence breast cancer risk. We investigated the association between genetic variation in the hormone metabolism and signaling pathway and mammographic density (MD), a strong predictor of breast cancer risk. Methods We genotyped 161 SNPs in 15 hormone metabolism pathway gene regions and evaluated MD in 2,038 Singapore Chinese women. Linear regression analysis was used to investigate SNP-MD association. An overall pathway summary was obtained using the adaptive ranked truncated product test. Results We did not find any of the individually tested SNPs to be associated with MD after a multiple testing correction. There was no evidence of an overall effect on MD of genetic variation in the hormone metabolism pathway. Conclusions In this cross-sectional study, genetic variation in hormone metabolism pathway was not associated with MD in Singapore Chinese women. Impact Consistent with existing data from Caucasian populations, polymorphisms in hormone pathway genes are not likely to be strong predictors of MD in Asian women. PMID:23429186

  2. Mammographic density and risk of breast cancer in Korean women.

    PubMed

    Kim, Bo-Kyoung; Choi, Yoon-Ho; Nguyen, Tuong L; Nam, Seok Jin; Lee, Jeong Eon; Hopper, John L; Sung, Joohon; Song, Yun-Mi

    2015-09-01

    We carried out this study to evaluate the association between mammographic density adjusted for age and BMI and early-onset breast cancer in Asian women. We recruited 213 Korean patients with breast cancer (45% diagnosed before the age of 50 years) and 630 controls matched for age, menopausal status, and examination date. The percentage and absolute size of dense areas on digital mammograms were measured using a computer-assisted thresholding technique (Cumulus). We carried out an analysis using the conditional logistic regression model with adjustment for covariates. An increase by 1 SD in age and BMI-adjusted absolute dense area and percentage dense area was associated with a 1.15-fold (95% confidence interval: 1.03, 1.29) and 1.20-fold (95% confidence interval: 1.06, 1.37) increased risk of breast cancer, respectively. These associations were stronger for premenopausal disease (P=0.07 and 0.01, respectively) and for disease diagnosed before age 50 (P=0.07 and 0.02, respectively) than for postmenopausal disease (P=0.16 and 0.23, respectively) or later onset disease (P=0.10 and 0.10, respectively). There was no difference in the associations with premenopausal versus postmenopausal and early-onset versus late-onset disease. After adjusting for age and BMI, both a greater absolute dense area and a greater percentage dense area were associated with an increased risk of breast cancer, particularly at a young age.

  3. Multiple metabolic risk factors and mammographic breast density

    PubMed Central

    Tehranifar, Parisa; Reynolds, Diane; Fan, Xiaozhou; Boden-Albala, Bernadette; Engmann, Natalie J.; Flom, Julie D.; Terry, Mary Beth

    2014-01-01

    Purpose We examined whether obesity and a history of diabetes, hypertension, and elevated cholesterol, individually and in combination, are associated with breast density, a strong risk factor for breast cancer. Methods We measured percent density and dense area using a computer-assisted method (n=191; age range=40-61 years). We used linear regression models to examine the associations of each metabolic condition and the number of metabolic conditions (0, 1, 2, and 3 or 4 conditions) with breast density. Results Among individual metabolic conditions, only high blood cholesterol was inversely associated with percent density (β=-5.4, 95% CI: -8.5, -2.2) and dense area (β= -6.7, 95% CI=-11.1, -2.4). Having multiple metabolic conditions was also associated with lower breast density, with 2 conditions and 3 or 4 conditions vs. 0 conditions associated with 6.4% (95% CI:-11.2, -1.6) and 7.4% (95% CI:-12.9, -1.9) reduction in percent density and with 6.5 cm2 (95% CI: -13.1, -0.1) and 9.5 cm2 (95% CI: -17.1, -1.9) smaller dense area. Conclusions A history of high blood cholesterol and multiple metabolic conditions were associated with lower relative and absolute measures of breast density. The positive association between metabolic abnormalities and breast cancer risk may be driven by pathways unrelated to mammographic breast density. PMID:24698111

  4. Local mammographic density as a predictor of breast cancer

    NASA Astrophysics Data System (ADS)

    Otsuka, Mayu; Harkness, Elaine F.; Chen, Xin; Moschidis, Emmanouil; Bydder, Megan; Gadde, Soujanya; Lim, Yit Y.; Maxwell, Anthony J.; Evans, Gareth D.; Howell, Anthony; Stavrinos, Paula; Wilson, Mary; Astley, Susan M.

    2015-03-01

    High overall mammographic density is associated with both an increased risk of developing breast cancer and the risk of cancer being masked. We compared local density at cancer sites in diagnostic images with corresponding previous screening mammograms (priors), and matched controls. VolparaTM density maps were obtained for 54 mammograms showing unilateral breast cancer and their priors which had been previously read as normal. These were each matched to 3 controls on age, menopausal status, hormone replacement therapy usage, body mass index and year of prior. Local percent density was computed in 15mm square regions at lesion sites and similar locations in the corresponding images. Conditional logistic regression was used to predict case-control status. In diagnostic and prior images, local density was increased at the lesion site compared with the opposite breast (medians 21.58%, 9.18%, p<0.001 diagnostic; 18.82%, 9.45%, p <0.001 prior). Women in the highest tertile of local density in priors were more likely to develop cancer than those in the lowest tertile (OR 42.09, 95% CI 5.37-329.94). Those in the highest tertile of VolparaTM gland volume were also more likely to develop cancer (OR 2.89, 95% CI 1.30-6.42). Local density is increased where cancer will develop compared with corresponding regions in the opposite breast and matched controls, and its measurement could enhance computer-aided mammography.

  5. Mammographic Breast Density Patterns in Asymptomatic Mexican Women

    PubMed Central

    Calderón-Garcidueñas, Ana Laura; Sanabria-Mondragón, Mónica; Hernández-Beltrán, Lourdes; López-Amador, Noé; Cerda-Flores, Ricardo M.

    2012-01-01

    Breast density (BD) is a risk factor for breast cancer. Aims. To describe BD patterns in asymptomatic Mexican women and the pathological mammographic findings. Methods and Material. Prospective, descriptive, and comparative study. Women answered a questionnaire and their mammograms were analyzed according to BI-RADS. Univariate (χ2) and conditional logistic regression analyses were performed. Results. In 300 women studied the BD patterns were fat 56.7% (170), fibroglandular 29% (87), heterogeneously dense 5.7% (17), and dense pattern 8.6% (26). Prevalence of fat pattern was significantly different in women under 50 years (37.6%, 44/117) and older than 50 (68.8%, 126/183). Patterns of high breast density (BD) (dense + heterogeneously dense) were observed in 25.6% (30/117) of women ≤50 years and 7.1% (13/183) of women >50. Asymmetry in BD was observed in 22% (66/300). Compression cone ruled out underlying disease in 56 cases. In the remaining 10, biopsy revealed one fibroadenoma, one complex cyst, and 6 invasive and 2 intraductal carcinomas. 2.6% (8/300) of patients had non-palpable carcinomas. Benign lesions were observed in 63.3% (190/300) of cases, vascular calcification in 150 cases (78.9%), and fat necrosis in 38 cases (20%). Conclusions. Mexican women have a low percentage of high-density patterns. PMID:23346398

  6. Monochromatic Mammographic Imaging Using X-Ray Polycapillary Optics

    NASA Astrophysics Data System (ADS)

    Sugiro, Francisca

    2002-06-01

    Monochromatic imaging is typically done with synchrotron sources. These sources are expensive and not practical for clinical settings. However, conventional laboratory sources normally have insufficient intensity. Polycapillary x-ray optics can be used to efficiently produce an intense parallel beam, which can be diffracted from a crystal to create monochromatic radiation. Monochromatic parallel beam imaging produces high subject contrast, high resolution, and low patient dose. Contrast, resolution, and intensity measurements were performed with both high and low angular acceptance crystals. Testing was first done at 8 keV with an intense copper rotating anode source. Preliminary l7.5 kev measurements were then made with a molybdenum source. At 8 keV, contrast enhancement was a factor of five relative to the polychromatic case, in good agreement with theoretical values. At l7.5 kev, monochromatic subject contrast was a factor of two times greater than the conventional polychromatic contrast. The measured angular resolution with a silicon crystal is 0.6 mrad at 8 keV, and 0.2 - 0.3 mrad at 17.5 keV. For a 50-mm thick patient, this angle corresponds to 50 lp/mm with an ideal detector. The use of polychromatic collimating optics allow monochromatic mammographic imaging measurements with a conventional x-ray source in a practical clinical setting.

  7. Breast cancer risk and participation in mammographic screening.

    PubMed Central

    Taplin, S; Anderman, C; Grothaus, L

    1989-01-01

    Within the context of an organized breast cancer screening program we conducted a prospective evaluation of the relation between breast cancer risk and participation in mammographic screening. The influence on participation of known breast cancer risk factors, as well as a summary risk label, (i.e. "high", or "moderate") were examined. The overall participation rate was 71 percent among 2,422 women, 50 to 79 years of age, invited to a centralized clinic. Multivariate analyses showed participation to be somewhat decreased among women with late menopause and definitely increased among women with any of the following factors: 1) increased age; 2) a family history of breast cancer; and 3) a previous breast biopsy. Women in the high-risk group were most likely to participate but the effect of the label was stronger among women ages 50 to 59 compared to women ages 60 to 79. The study results are generally consistent with previous findings that participants in screening programs have higher rates of breast cancer. The results also suggest the possibility that providing breast cancer risk information may encourage participation in screening. PMID:2817159

  8. Association of a mammographic parenchymal pattern (MPP) descriptor with breast cancer risk: a case-control study

    NASA Astrophysics Data System (ADS)

    Wei, Jun; Chan, Heang-Ping; Zhou, Chuan; Helvie, Mark A.; Hadjiiski, Lubomir M.; Sahiner, Berkman

    2010-03-01

    We are investigating the feasibility of improving breast cancer risk prediction by computerized mammographic parenchymal pattern (MPP) analysis. A case-control study was conducted to investigate the association of the MPP measures with breast cancer risk. The case group included 168 contralateral CC-view mammograms of breast cancer patients dated at least one year prior to cancer diagnosis, and the control group included 522 CC-view mammograms from one breast of normal subjects. We extracted and compared four types of statistical texture feature spaces that included run length statistics and region size statistics (RLS/RSS) features, spatial gray level dependence (SGLD) features, gray level difference statistics (GLDS) features, and the feature space combining these three types of texture features. A linear discriminant analysis (LDA) classifier with stepwise feature selection was trained and tested with leave-one-case-out resampling to evaluate whether the breast parenchyma of future cancer patients could be distinguished from those of normal subjects in each feature space. The areas under ROC curves (Az) were 0.71, 0.72, 0.71 and 0.76 for the four feature spaces, respectively. The Az obtained from the combined feature space was significantly (p<0.05) higher than those from the individual feature spaces. Odd ratios (OR) were used to assess the association between breast cancer risk and four categories of MPP measures: <0.1 (C1), 0.1-0.15 (C2), 0.15-0.2 (C3), and >0.2 (C4) while patient age was treated as a confounding factor. The adjusted ORs of breast cancer for C2, C3 and C4 were 3.23, 7.77 and 25.43, respectively. The preliminary result indicated that our proposed computerized MPP measures were strongly associated with breast cancer risk.

  9. No Effect of Aspirin on Mammographic Density in a Randomized Controlled Clinical Trial

    PubMed Central

    McTiernan, Anne; Wang, CY; Sorensen, Bess; Xiao, Liren; Buist, Diana S. M.; Bowles, Erin J. Aiello; White, Emily; Rossing, Mary Anne; Potter, John; Urban, Nicole

    2009-01-01

    Background: Epidemiologic studies suggest a reduced risk of breast cancer among women who regularly use aspirin; a plausible mechanism is through aspirin effect on mammographic breast density, a breast cancer risk factor, possibly mediated through aspirin interference with estrogen synthesis. Methods: In a 2-arm randomized placebo-controlled clinical trial, we evaluated the effects of 6-months administration of 325 mg/day aspirin on total mammographic breast dense area and percent of the mammographic breast image occupied by dense areas (% density) in 143 postmenopausal women. Eligible women, recruited 2005-7, were healthy, not taking hormone therapy, with elevated mammographic breast density (American College of Radiology Breast Imaging Reporting and Data System (BI-RADS®) density category 2, 3 or 4) within 6 months prior to enrollment. Results: Women were a mean (s.d.) 59.5 (5.5) years. Geometric mean baseline percent density was 17.6% (95% CI 14.8, 20.9) in women randomized to aspirin and 19.2% (95% CI 16.3, 22.7) in women randomized to placebo. Percent density decreased in women randomized to aspirin by an absolute 0.8% vs. an absolute decrease of 1.2% in controls (p = 0.84). Total breast area and dense area decreased to a similar degree in women assigned to aspirin and in those assigned to placebo, with no differences statistically significantly different between trial arms. Conclusions: A single daily administration of adult-dose aspirin for 6 months had no effect on mammographic density in postmenopausal women. If aspirin affects breast cancer risk in postmenopausal women, it may do so through alternative pathways than mammographic breast density. PMID:19423529

  10. Mammographic density and breast cancer risk in White and African American Women

    PubMed Central

    Troester, Melissa A.; Gierach, Gretchen L.; Olshan, Andrew F.; Yankaskas, Bonnie C.; Millikan, Robert C.

    2013-01-01

    Mammographic density is a strong risk factor for breast cancer, but limited data are available in African American (AA) women. We examined the association between mammographic density and breast cancer risk in AA and white women. Cases (n = 491) and controls (n = 528) were from the Carolina Breast Cancer Study (CBCS) who also had mammograms recorded in the Carolina Mammography Registry (CMR). Mammographic density was reported to CMR using Breast Imaging Reporting and Data System (BI-RADS) categories. Increasing mammographic density was associated with increased breast cancer risk among all women. After adjusting for potential confounders, a monotonically increasing risk of breast cancer was observed between the highest versus the lowest BI-RADS density categories [OR = 2.45, (95 % confidence interval: 0.99, 6.09)]. The association was stronger in whites, with ~40 % higher risk among those with extremely dense breasts compared to those with scattered fibroglandular densities [1.39, (0.75, 2.55)]. In AA women, the same comparison suggested lower risk [0.75, (0.30, 1.91)]. Because age, obesity, and exogenous hormones have strong associations with breast cancer risk, mammographic density, and race in the CBCS, effect measure modification by these factors was considered. Consistent with previous literature, density-associated risk was greatest among those with BMI > 30 and current hormone users (P value = 0.02 and 0.01, respectively). In the CBCS, mammographic density is associated with increased breast cancer risk, with some suggestion of effect measure modification by race, although results were not statistically significant. However, exposures such as BMI and hormone therapy may be important modifiers of this association and merit further investigation. PMID:22864770

  11. Mammographic density and breast cancer risk in White and African American Women.

    PubMed

    Razzaghi, Hilda; Troester, Melissa A; Gierach, Gretchen L; Olshan, Andrew F; Yankaskas, Bonnie C; Millikan, Robert C

    2012-09-01

    Mammographic density is a strong risk factor for breast cancer, but limited data are available in African American (AA) women. We examined the association between mammographic density and breast cancer risk in AA and white women. Cases (n = 491) and controls (n = 528) were from the Carolina Breast Cancer Study (CBCS) who also had mammograms recorded in the Carolina Mammography Registry (CMR). Mammographic density was reported to CMR using Breast Imaging Reporting and Data System (BI-RADS) categories. Increasing mammographic density was associated with increased breast cancer risk among all women. After adjusting for potential confounders, a monotonically increasing risk of breast cancer was observed between the highest versus the lowest BI-RADS density categories [OR = 2.45, (95 % confidence interval: 0.99, 6.09)]. The association was stronger in whites, with ~40 % higher risk among those with extremely dense breasts compared to those with scattered fibroglandular densities [1.39, (0.75, 2.55)]. In AA women, the same comparison suggested lower risk [0.75, (0.30, 1.91)]. Because age, obesity, and exogenous hormones have strong associations with breast cancer risk, mammographic density, and race in the CBCS, effect measure modification by these factors was considered. Consistent with previous literature, density-associated risk was greatest among those with BMI > 30 and current hormone users (P value = 0.02 and 0.01, respectively). In the CBCS, mammographic density is associated with increased breast cancer risk, with some suggestion of effect measure modification by race, although results were not statistically significant. However, exposures such as BMI and hormone therapy may be important modifiers of this association and merit further investigation.

  12. Spectral analysis of mammographic images using a multitaper method

    SciTech Connect

    Wu Gang; Mainprize, James G.; Yaffe, Martin J.

    2012-02-15

    Purpose: Power spectral analysis in radiographic images is conventionally performed using a windowed overlapping averaging periodogram. This study describes an alternative approach using a multitaper technique and compares its performance with that of the standard method. This tool will be valuable in power spectrum estimation of images, whose content deviates significantly from uniform white noise. The performance of the multitaper approach will be evaluated in terms of spectral stability, variance reduction, bias, and frequency precision. The ultimate goal is the development of a useful tool for image quality assurance. Methods: A multitaper approach uses successive data windows of increasing order. This mitigates spectral leakage allowing one to calculate a reduced-variance power spectrum. The multitaper approach will be compared with the conventional power spectrum method in several typical situations, including the noise power spectra (NPS) measurements of simulated projection images of a uniform phantom, NPS measurement of real detector images of a uniform phantom for two clinical digital mammography systems, and the estimation of the anatomic noise in mammographic images (simulated images and clinical mammograms). Results: Examination of spectrum variance versus frequency resolution and bias indicates that the multitaper approach is superior to the conventional single taper methods in the prevention of spectrum leakage and variance reduction. More than four times finer frequency precision can be achieved with equivalent or less variance and bias. Conclusions: Without any shortening of the image data length, the bias is smaller and the frequency resolution is higher with the multitaper method, and the need to compromise in the choice of regions of interest size to balance between the reduction of variance and the loss of frequency resolution is largely eliminated.

  13. Mammographic density and serum 25-hydroxyvitamin D levels

    PubMed Central

    2014-01-01

    Background Vitamin D, which influences cellular proliferation and breast tissue characteristics, has been inversely correlated with breast cancer risk. Dietary vitamin D intake has been associated with lower mammographic density (MD), a strong intermediate marker of breast cancer risk. Findings We examined the relationship between MD and serum 25-hydroxyvitamin D [25(OH)D], an integrated measure of vitamin D status from dietary sources and sunlight exposure, in a multi-ethnic cohort of women undergoing screening mammography. We recruited women age 40–60 years without a history of breast cancer at the time of their routine screening mammogram, and conducted in-person interviews and collected blood specimens. We enrolled 195 women from 2007–2008, 120 gave blood, and 114 were evaluable, including 25% white, 41% African American, 18% African Caribbean, and 16% Hispanic. We digitized mammograms and calculated percent density, dense area, and non-dense area on cranial-caudal images. We measured serum 25(OH)D in batched, archived specimens. Median serum 25(OH)D was 22 ng/ml (range, 8–66 ng/ml). In univariable analysis, higher serum 25(OH)D was associated with white race, higher educational level, ever breast feeding, and blood draw during the summer. After adjusting for body mass index and other confounders, we found no association between serum 25(OH)D and different measures of MD. However, when stratified by season, 25(OH)D was inversely associated with dense area during July-December (p = 0.034). Conclusions Overall, our findings suggest that circulating vitamin D, a potentially modifiable breast cancer risk factor, is not associated with MD; the seasonal effects we observed need to be replicated in larger cohorts. PMID:24742098

  14. Time-frequency analysis of functional optical mammographic images

    NASA Astrophysics Data System (ADS)

    Barbour, Randall L.; Graber, Harry L.; Schmitz, Christoph H.; Tarantini, Frank; Khoury, Georges; Naar, David J.; Panetta, Thomas F.; Lewis, Theophilus; Pei, Yaling

    2003-07-01

    We have introduced working technology that provides for time-series imaging of the hemoglobin signal in large tissue structures. In this study we have explored our ability to detect aberrant time-frequency responses of breast vasculature for subjects with Stage II breast cancer at rest and in response to simple provocations. The hypothesis being explored is that time-series imaging will be sensitive to the known structural and functional malformations of the tumor vasculature. Mammographic studies were conducted using an adjustable hemisheric measuring head containing 21 source and 21 detector locations (441 source-detector pairs). Simultaneous dual-wavelength studies were performed at 760 and 830 nm at a framing rate of ~2.7 Hz. Optical measures were performed on women lying prone with the breast hanging in a pendant position. Two class of measures were performed: (1) 20- minute baseline measure wherein the subject was at rest; (2) provocation studies wherein the subject was asked to perform some simple breathing maneuvers. Collected data were analyzed to identify the time-frequency structure and central tendencies of the detector responses and those of the image time series. Imaging data were generated using the Normalized Difference Method (Pei et al., Appl. Opt. 40, 5755-5769, 2001). Results obtained clearly document three classes of anomalies when compared to the normal contralateral breast. 1) Breast tumors exhibit altered oxygen supply/demand imbalance in response to an oxidative challenge (breath hold). 2) The vasomotor response of the tumor vasculature is mainly depressed and exhibits an altered modulation. 3) The affected area of the breast wherein the altered vasomotor signature is seen extends well beyond the limits of the tumor itself.

  15. Matching mammographic regions in mediolateral oblique and cranio caudal views: a probabilistic approach

    NASA Astrophysics Data System (ADS)

    Samulski, Maurice; Karssemeijer, Nico

    2008-03-01

    Most of the current CAD systems detect suspicious mass regions independently in single views. In this paper we present a method to match corresponding regions in mediolateral oblique (MLO) and craniocaudal (CC) mammographic views of the breast. For every possible combination of mass regions in the MLO view and CC view, a number of features are computed, such as the difference in distance of a region to the nipple, a texture similarity measure, the gray scale correlation and the likelihood of malignancy of both regions computed by single-view analysis. In previous research, Linear Discriminant Analysis was used to discriminate between correct and incorrect links. In this paper we investigate if the performance can be improved by employing a statistical method in which four classes are distinguished. These four classes are defined by the combinations of view (MLO/CC) and pathology (TP/FP) labels. We use distance-weighted k-Nearest Neighbor density estimation to estimate the likelihood of a region combination. Next, a correspondence score is calculated as the likelihood that the region combination is a TP-TP link. The method was tested on 412 cases with a malignant lesion visible in at least one of the views. In 82.4% of the cases a correct link could be established between the TP detections in both views. In future work, we will use the framework presented here to develop a context dependent region matching scheme, which takes the number and likelihood of possible alternatives into account. It is expected that more accurate determination of matching probabilities will lead to improved CAD performance.

  16. High and low mammographic density human breast tissues maintain histological differential in murine tissue engineering chambers.

    PubMed

    Chew, G L; Huang, D; Lin, S J; Huo, C; Blick, T; Henderson, M A; Hill, P; Cawson, J; Morrison, W A; Campbell, I G; Hopper, J L; Southey, M C; Haviv, I; Thompson, E W

    2012-08-01

    Mammographic density (MD) is the area of breast tissue that appears radiologically white on mammography. Although high MD is a strong risk factor for breast cancer, independent of BRCA1/2 mutation status, the molecular basis of high MD and its associated breast cancer risk is poorly understood. MD studies will benefit from an animal model, where hormonal, gene and drug perturbations on MD can be measured in a preclinical context. High and low MD tissues were selectively sampled by stereotactic biopsy from operative specimens of high-risk women undergoing prophylactic mastectomy. The high and low MD tissues were transferred into separate vascularised biochambers in the groins of SCID mice. Chamber material was harvested after 6 weeks for histological analyses and immunohistochemistry for cytokeratins, vimentin and a human-specific mitochondrial antigen. Within-individual analysis was performed in replicate mice, eliminating confounding by age, body mass index and process-related factors, and comparisons were made to the parental human tissue. Maintenance of differential MD post-propagation was assessed radiographically. Immunohistochemical staining confirmed the preservation of human glandular and stromal components in the murine biochambers, with maintenance of radiographic MD differential. Propagated high MD regions had higher stromal (p = 0.0002) and lower adipose (p = 0.0006) composition, reflecting the findings in the original human breast tissue, although glands appeared small and non-complex in both high and low MD groups. No significant differences were observed in glandular area (p = 0.4) or count (p = 0.4) between high and low MD biochamber tissues. Human mammary glandular and stromal tissues were viably maintained in murine biochambers, with preservation of differential radiographic density and histological features. Our study provides a murine model for future studies into the biomolecular basis of MD as a risk factor for breast cancer.

  17. An investigation of mammographic density and gene variants in healthy women.

    PubMed

    Maskarinec, Gertraud; Lurie, Galina; Williams, Andrew E; Le Marchand, Loic

    2004-11-20

    This cross-sectional study examined if polymorphisms in genes that code for enzymes involved in the production and metabolism of estrogens are associated with mammographic density, a strong predictor of breast cancer risk. The study included 328 healthy women of different ethnicities who underwent mammographic screening and donated a blood or mouthwash sample for DNA analysis. After digitizing cranio-caudal views of the mammograms, we performed computer-assisted mammographic density assessment. Following DNA extraction, samples were analyzed for polymorphisms in the COMT (Val158Met), CYP1A1 (Ile462Val), CYP1B1 (Val432Leu), CYP1A2 (*1F) and CYP17 (T27C) genes using PCR-RFLP. Breast density was lower in Caucasians than in Asians. Caucasian women were less likely to carry the CYP1A1 variant allele and more likely to carry the variant alleles for CYP1B1 and COMT than women with Asian or Hawaiian ancestry. The low-activity COMT and CYP1A2 variant alleles were weakly related to lower percent mammographic density after adjustment for age, ethnicity, body mass index and reproductive variables (p for gene-dosage =0.08 and 0.05, respectively). These relations were observed in premenopausal women only and were similar in direction and magnitude after stratification by ethnicity. We found no significant associations between breast density and the variant alleles for CYP1A1, CYP1B1 and CYP17. Our data suggest lower mammographic density for women carrying the COMT and CYP1A2 variant alleles than for women carrying the common alleles, though this is the opposite of what is commonly hypothesized from the enzyme function.

  18. Improving CAD performance by fusion of the bilateral mammographic tissue asymmetry information

    NASA Astrophysics Data System (ADS)

    Wang, Xingwei; Li, Lihua; Liu, Wei; Xu, Weidong; Lederman, Dror; Zheng, Bin

    2012-03-01

    Bilateral mammographic tissue density asymmetry could be an important factor in assessing risk of developing breast cancer and improving the detection of the suspicious lesions. This study aims to assess whether fusion of the bilateral mammographic density asymmetrical information into a computer-aided detection (CAD) scheme could improve CAD performance in detecting mass-like breast cancers. A testing dataset involving 1352 full-field digital mammograms (FFDM) acquired from 338 cases was used. In this dataset, half (169) cases are positive containing malignant masses and half are negative. Two computerized schemes were first independently applied to process FFDM images of each case. The first single-image based CAD scheme detected suspicious mass regions on each image. The second scheme detected and computed the bilateral mammographic tissue density asymmetry for each case. A fusion method was then applied to combine the output scores of the two schemes. The CAD performance levels using the original CAD-generated detection scores and the new fusion scores were evaluated and compared using a free-response receiver operating characteristic (FROC) type data analysis method. By fusion with the bilateral mammographic density asymmetrical scores, the case-based CAD sensitivity was increased from 79.2% to 84.6% at a false-positive rate of 0.3 per image. CAD also cued more "difficult" masses with lower CAD-generated detection scores while discarded some "easy" cases. The study indicated that fusion between the scores generated by a single-image based CAD scheme and the computed bilateral mammographic density asymmetry scores enabled to increase mass detection sensitivity in particular to detect more subtle masses.

  19. Robust estimation of mammographic breast density: a patient-based approach

    NASA Astrophysics Data System (ADS)

    Heese, Harald S.; Erhard, Klaus; Gooßen, Andre; Bulow, Thomas

    2012-02-01

    Breast density has become an established risk indicator for developing breast cancer. Current clinical practice reflects this by grading mammograms patient-wise as entirely fat, scattered fibroglandular, heterogeneously dense, or extremely dense based on visual perception. Existing (semi-) automated methods work on a per-image basis and mimic clinical practice by calculating an area fraction of fibroglandular tissue (mammographic percent density). We suggest a method that follows clinical practice more strictly by segmenting the fibroglandular tissue portion directly from the joint data of all four available mammographic views (cranio-caudal and medio-lateral oblique, left and right), and by subsequently calculating a consistently patient-based mammographic percent density estimate. In particular, each mammographic view is first processed separately to determine a region of interest (ROI) for segmentation into fibroglandular and adipose tissue. ROI determination includes breast outline detection via edge-based methods, peripheral tissue suppression via geometric breast height modeling, and - for medio-lateral oblique views only - pectoral muscle outline detection based on optimizing a three-parameter analytic curve with respect to local appearance. Intensity harmonization based on separately acquired calibration data is performed with respect to compression height and tube voltage to facilitate joint segmentation of available mammographic views. A Gaussian mixture model (GMM) on the joint histogram data with a posteriori calibration guided plausibility correction is finally employed for tissue separation. The proposed method was tested on patient data from 82 subjects. Results show excellent correlation (r = 0.86) to radiologist's grading with deviations ranging between -28%, (q = 0.025) and +16%, (q = 0.975).

  20. Sclerosing adenosis: Ultrasonographic and mammographic findings and correlation with histopathology

    PubMed Central

    Chen, Ya-Ling; Chen, Jia-Jian; Chang, Cai; Gao, Yi; Wu, Jiong; Yang, Wen-Tao; Gu, Ya-Jia

    2017-01-01

    The present study was conducted to evaluate the radiological findings, particularly the ultrasonographic (US) characteristics of sclerosing adenosis (SA), and their correlation with histopathological results. A retrospective review identified 191 patients with a total of 200 lesions histopathologically confirmed as SA following breast surgery between July 2009 and December 2012. Of the 191 patients, 145 (151 lesions) with SA as the major component were included for US and mammographic (MG) analysis. All 145 patients analyzed were female, with a mean age ± standard deviation of 46.8±7.8 years (range, 25–71 years). All 145 patients underwent US examination and the imaging findings included heterogeneously echogenic areas in 9.3% (14/151), masses in 51.7% (78/151), masses with calcifications in 13.9% (21/151), focal acoustic shadowing in 4.0% (6/151) and were negative in 21.2% (32/151) patients. Among the 119 lesions with visible abnormalities, 87.4% (104/119) were hypoechoic, 58.0% (69/119) were irregular in shape, 52.1% (62/119) had an ill-defined margin, calcifications were found in 17.6% (21/119) and 7.6% (9/119) were hypervascular, while none of the characteristics mentioned above were significantly correlated with histopathology. A total of 136 patients underwent MG at the Fudan University Shanghai Cancer Center, and the imaging findings included microcalcifications in 31.6% (43/136), masses in 23.5% (32/136), asymmetric focal density in 14.7% (20/136), focal architectural distortion in 22.8% (31/136), and were negative in 7.4% (10/136). The mass lesions were fewer on MG compared with US (23.5 vs. 65.6%, respectively). The area under the curve of US distinguishing between benign and malignant lesions was significantly larger compared with that of MG (0.547 vs. 0.497, respectively; P=0.036). In the 60 lesions that were overestimated by Breast Imaging Reporting and Data System US category, one or more characteristics of malignancy were found on US imaging. The

  1. Qualitative research.

    PubMed

    Gelling, Leslie

    2015-03-25

    Qualitative research has an important role in helping nurses and other healthcare professionals understand patient experiences of health and illness. Qualitative researchers have a large number of methodological options and therefore should take care in planning and conducting their research. This article offers a brief overview of some of the key issues qualitative researchers should consider.

  2. Qualitative modeling.

    PubMed

    Forbus, Kenneth D

    2011-07-01

    Qualitative modeling concerns the representations and reasoning that people use to understand continuous aspects of the world. Qualitative models formalize everyday notions of causality and provide accounts of how to ground symbolic, relational representations in perceptual processes. This article surveys the basic ideas of qualitative modeling and their applications from a cognitive science perspective. It describes the basic principles of qualitative modeling, and a variety of qualitative representations that have been developed for quantities and for relationships between them, providing a kind of qualitative mathematics. Three ontological frameworks for organizing modeling knowledge (processes, components, and field) are summarized, along with research on automatically assembling models for particular tasks from such knowledge. Qualitative simulation and how it carves up time into meaningful units is discussed. We discuss several accounts of causal reasoning about dynamical systems, based on different choices of qualitative mathematics and ontology. Qualitative spatial reasoning is explored, both in terms of relational systems and visual reasoning. Applications of qualitative models of particular interest to cognitive scientists are described, including how they have been used to capture the expertise of scientists and engineers and how they have been used in education. Open questions and frontiers are also discussed, focusing on relationships between ideas developed in the qualitative modeling community and other areas of cognitive science. WIREs Cogni Sci 2011 2 374-391 DOI: 10.1002/wcs.115 For further resources related to this article, please visit the WIREs website.

  3. Sampling in Qualitative Research

    PubMed Central

    LUBORSKY, MARK R.; RUBINSTEIN, ROBERT L.

    2011-01-01

    In gerontology the most recognized and elaborate discourse about sampling is generally thought to be in quantitative research associated with survey research and medical research. But sampling has long been a central concern in the social and humanistic inquiry, albeit in a different guise suited to the different goals. There is a need for more explicit discussion of qualitative sampling issues. This article will outline the guiding principles and rationales, features, and practices of sampling in qualitative research. It then describes common questions about sampling in qualitative research. In conclusion it proposes the concept of qualitative clarity as a set of principles (analogous to statistical power) to guide assessments of qualitative sampling in a particular study or proposal. PMID:22058580

  4. Amount of stroma is associated with mammographic density and stromal expression of oestrogen receptor in normal breast tissues.

    PubMed

    Gabrielson, Marike; Chiesa, Flaminia; Paulsson, Janna; Strell, Carina; Behmer, Catharina; Rönnow, Katarina; Czene, Kamila; Östman, Arne; Hall, Per

    2016-07-01

    Following female sex and age, mammographic density is considered one of the strongest risk factors for breast cancer. Despite the association between mammographic density and breast cancer risk, little is known about the underlying histology and biological basis of breast density. To better understand the mechanisms behind mammographic density we assessed morphology, proliferation and hormone receptor status in relation to mammographic density in breast tissues from healthy women. Tissues were obtained from 2012-2013 by ultrasound-guided core needle biopsy from 160 women as part of the Karma (Karolinska mammography project for risk prediction for breast cancer) project. Mammograms were collected through routine mammography screening and mammographic density was calculated using STRATUS. The histological composition, epithelial and stromal proliferation status and hormone receptor status were assessed through immunohistochemical staining. Higher mammographic density was significantly associated with a greater proportion of stromal and epithelial tissue and a lower proportion of adipose tissue. Epithelial expression levels of Ki-67, oestrogen receptor (ER) and progesterone receptor (PR) were not associated with mammographic density. Epithelial Ki-67 was associated with a greater proportion of epithelial tissue, and epithelial PR was associated with a greater proportion of stromal and a lower proportion of adipose tissue. Epithelial ER was not associated with any tissues. In contrast, expression of ER in the stroma was significantly associated with a greater proportion of stroma, and negatively associated with the amount of adipose tissue. High mammographic density is associated with higher amount of stroma and epithelium and less amount of fat, but is not associated with a change in epithelial proliferation or receptor status. Increased expressions of both epithelial PR and stromal ER are associated with a greater proportion of stroma, suggesting hormonal involvement

  5. Computerized analysis of mammographic parenchymal patterns on a large clinical dataset of full-field digital mammograms: robustness study with two high-risk datasets.

    PubMed

    Li, Hui; Giger, Maryellen L; Lan, Li; Bancroft Brown, Jeremy; MacMahon, Aoife; Mussman, Mary; Olopade, Olufunmilayo I; Sennett, Charlene

    2012-10-01

    The purpose of this study was to demonstrate the robustness of our prior computerized texture analysis method for breast cancer risk assessment, which was developed initially on a limited dataset of screen-film mammograms. This current study investigated the robustness by (1) evaluating on a large clinical dataset, (2) using full-field digital mammograms (FFDM) as opposed to screen-film mammography, and (3) incorporating analyses over two types of high-risk patient sets, as well as patients at low risk for breast cancer. The evaluation included the analyses on the parenchymal patterns of women at high risk of developing of breast cancer, including both BRCA1/2 gene mutation carriers and unilateral cancer patients, and of women at low risk of developing breast cancer. A total of 456 cases, including 53 women with BRCA1/2 gene mutations, 75 women with unilateral cancer, and 328 low-risk women, were retrospectively collected under an institutional review board approved protocol. Regions-of-interest (ROIs), were manually selected from the central breast region immediately behind the nipple. These ROIs were subsequently used in computerized feature extraction to characterize the mammographic parenchymal patterns in the images. Receiver operating characteristic analysis was used to assess the performance of the computerized texture features in the task of distinguishing between high-risk and low-risk subjects. In a round robin evaluation on the FFDM dataset with Bayesian artificial neural network analysis, AUC values of 0.82 (95% confidence interval [0.75, 0.88]) and 0.73 (95% confidence interval [0.67, 0.78]) were obtained between BRCA1/2 gene mutation carriers and low-risk women, and between unilateral cancer and low-risk women, respectively. These results from computerized texture analysis on digital mammograms demonstrated that high-risk and low-risk women have different mammographic parenchymal patterns. On this large clinical dataset, we validated our methods for

  6. Breast cancer CAD{sub x} based on BI-RADS trade mark sign descriptors from two mammographic views

    SciTech Connect

    Gupta, Shalini; Chyn, Priscilla F.; Markey, Mia K.

    2006-06-15

    In this study we compared the performance of computer aided diagnosis (CAD{sub x}) algorithms based on Breast Imaging Reporting And Data System (BI-RADS trade mark sign ) descriptors from one or two views. To select cases for the study with different mediolateral (MLO) and craniocaudal (CC) view descriptors, we assessed the agreement in BI-RADS trade mark sign lesion descriptors, BI-RADS trade mark sign assessment, and subtlety ratings for 1626 cases from the Digital Database for Screening Mammogrpahy (DDSM) using kappa statistics. We used 115 mass cases with different descriptors for the two views to design linear discriminant analysis (LDA) based CAD{sub x} algorithms. The CAD{sub x} algorithms used BI-RADS trade mark sign descriptors and patient age as features. The algorithms based on BI-RADS trade mark sign descriptors from both the views performed marginally better than algorithms based on BI-RADS trade mark sign descriptors from a single view. A system that averaged the results of two classifiers trained separately on the MLO and CC views displayed the best performance (A{sub z}=0.920{+-}0.027). Thus, some improvement in performance of BI-RADS trade mark sign based CAD{sub x} algorithms may be achieved by combining information from two mammographic views.

  7. Reproductive and menstrual factors in relation to mammographic parenchymal patterns among perimenopausal women.

    PubMed Central

    Gram, I. T.; Funkhouser, E.; Tabar, L.

    1995-01-01

    The relationship between mammographic patterns and reproductive and menstrual factors was examined in 3640 Norwegian women, aged 40-56 years, participating in the Third Tromsö study conducted in 1986-87. Epidemiological data were obtained from questionnaires. The mammograms were categorised into five groups. This categorisation is based on anatomic-mammographic correlations, following three-dimensional (thick slice technique) histopathologic-mammographic comparisons, rather than simple pattern reading. Patterns 1-3 were combined into a low-risk group and patterns 4 and 5 into a high-risk group for analysis. Women who had more than four children were 90% less likely to have a high-risk pattern than nulliparous women (OR = 0.09, 95% CI 0.04-0.16) controlling for age, weight, height and menopausal status. Furthermore, those who first gave birth over 34 years of age were more than twice as likely to have a high-risk pattern than those giving birth in their teens (OR = 2.37, 95% CI 1.23-4.56) adjusting for parity. Among post-menopausal women, age at menarche was negatively (P for trend = 0.015) and late age at menopause positively (P for trend = 0.072) related to high-risk patterns. Among premenopausal women, age at menarche was positively related to high-risk patterns (P for trend = 0.001). Also, menopausal status rather than age was associated with high-risk patterns. These findings support the opinion that reproductive and menstrual factors are involved in determining the mammographic parenchymal pattern among perimenopausal women. PMID:7880753

  8. Mammographic quantitative image analysis and biologic image composition for breast lesion characterization and classification

    SciTech Connect

    Drukker, Karen Giger, Maryellen L.; Li, Hui; Duewer, Fred; Malkov, Serghei; Joe, Bonnie; Kerlikowske, Karla; Shepherd, John A.; Flowers, Chris I.; Drukteinis, Jennifer S.

    2014-03-15

    Purpose: To investigate whether biologic image composition of mammographic lesions can improve upon existing mammographic quantitative image analysis (QIA) in estimating the probability of malignancy. Methods: The study population consisted of 45 breast lesions imaged with dual-energy mammography prior to breast biopsy with final diagnosis resulting in 10 invasive ductal carcinomas, 5 ductal carcinomain situ, 11 fibroadenomas, and 19 other benign diagnoses. Analysis was threefold: (1) The raw low-energy mammographic images were analyzed with an established in-house QIA method, “QIA alone,” (2) the three-compartment breast (3CB) composition measure—derived from the dual-energy mammography—of water, lipid, and protein thickness were assessed, “3CB alone”, and (3) information from QIA and 3CB was combined, “QIA + 3CB.” Analysis was initiated from radiologist-indicated lesion centers and was otherwise fully automated. Steps of the QIA and 3CB methods were lesion segmentation, characterization, and subsequent classification for malignancy in leave-one-case-out cross-validation. Performance assessment included box plots, Bland–Altman plots, and Receiver Operating Characteristic (ROC) analysis. Results: The area under the ROC curve (AUC) for distinguishing between benign and malignant lesions (invasive and DCIS) was 0.81 (standard error 0.07) for the “QIA alone” method, 0.72 (0.07) for “3CB alone” method, and 0.86 (0.04) for “QIA+3CB” combined. The difference in AUC was 0.043 between “QIA + 3CB” and “QIA alone” but failed to reach statistical significance (95% confidence interval [–0.17 to + 0.26]). Conclusions: In this pilot study analyzing the new 3CB imaging modality, knowledge of the composition of breast lesions and their periphery appeared additive in combination with existing mammographic QIA methods for the distinction between different benign and malignant lesion types.

  9. Prognosis for Mammographically Occult, Early-Stage Breast Cancer Patients Treated With Breast-Conservation Therapy

    SciTech Connect

    Yang, Tzu-I. J.; Yang Qifeng; Haffty, Bruce G.; Moran, Meena S.

    2010-01-15

    Purpose: To compare mammographically occult (MamOcc) and mammographically positive (MamPos) early-stage breast cancer patients treated with breast-conservation therapy (BCT), to analyze differences between the two cohorts. Methods and Materials: Our two cohorts consisted of 214 MamOcc and 2168 MamPos patients treated with BCT. Chart reviews were conducted to assess mammogram reports and method of detection. All clinical-pathologic and outcome parameters were analyzed to detect differences between the two cohorts. Results: Median follow-up was 7 years. There were no differences in final margins, T stage, nodal status, estrogen/progesterone receptor status, or 'triple-negative' status. Significant differences included younger age at diagnosis (p < 0.0001), more positive family history (p = 0.0033), less HER-2+ disease (p = 0.0294), and 1{sup o} histology (p < 0.0001). At 10 years, the differences in overall survival, cause-specific survival, and distant relapse between the two groups did not differ significantly. The MamOcc cohort had more breast relapses (15% vs. 8%; p = 0.0357), but on multivariate analysis this difference was not significant (hazard ratio 1.0, 95% confidence interval 0.993-1.007, p = 0.9296). Breast relapses were mammographically occult in 32% of the MamOcc and 12% of the MamPos cohorts (p = 0.0136). Conclusions: Although our study suggests that there are clinical-pathologic variations for the MamOcc cohort vs. MamPos patients that may ultimately affect management, breast relapse after BCT was not significantly different. Breast recurrences were more often mammographically occult in the MamOcc cohort; consideration should be given to closer follow-up and alternative imaging strategies (ultrasound, breast MRI) for routine posttreatment examination. To our knowledge, this represents the largest series addressing the prognostic significance of MamOcc cancers treated with BCT.

  10. International Consortium on Mammographic Density: Methodology and population diversity captured across 22 countries.

    PubMed

    McCormack, Valerie A; Burton, Anya; dos-Santos-Silva, Isabel; Hipwell, John H; Dickens, Caroline; Salem, Dorria; Kamal, Rasha; Hartman, Mikael; Lee, Charmaine Pei Ling; Chia, Kee-Seng; Ozmen, Vahit; Aribal, Mustafa Erkin; Flugelman, Anath Arzee; Lajous, Martín; Lopez-Riduara, Ruy; Rice, Megan; Romieu, Isabelle; Ursin, Giske; Qureshi, Samera; Ma, Huiyan; Lee, Eunjung; van Gils, Carla H; Wanders, Johanna O P; Vinayak, Sudhir; Ndumia, Rose; Allen, Steve; Vinnicombe, Sarah; Moss, Sue; Won Lee, Jong; Kim, Jisun; Pereira, Ana; Garmendia, Maria Luisa; Sirous, Reza; Sirous, Mehri; Peplonska, Beata; Bukowska, Agnieszka; Tamimi, Rulla M; Bertrand, Kimberly; Nagata, Chisato; Kwong, Ava; Vachon, Celine; Scott, Christopher; Perez-Gomez, Beatriz; Pollan, Marina; Maskarinec, Gertraud; Giles, Graham; Hopper, John; Stone, Jennifer; Rajaram, Nadia; Teo, Soo-Hwang; Mariapun, Shivaani; Yaffe, Martin J; Schüz, Joachim; Chiarelli, Anna M; Linton, Linda; Boyd, Norman F

    2016-02-01

    Mammographic density (MD) is a quantitative trait, measurable in all women, and is among the strongest markers of breast cancer risk. The population-based epidemiology of MD has revealed genetic, lifestyle and societal/environmental determinants, but studies have largely been conducted in women with similar westernized lifestyles living in countries with high breast cancer incidence rates. To benefit from the heterogeneity in risk factors and their combinations worldwide, we created an International Consortium on Mammographic Density (ICMD) to pool individual-level epidemiological and MD data from general population studies worldwide. ICMD aims to characterize determinants of MD more precisely, and to evaluate whether they are consistent across populations worldwide. We included 11755 women, from 27 studies in 22 countries, on whom individual-level risk factor data were pooled and original mammographic images were re-read for ICMD to obtain standardized comparable MD data. In the present article, we present (i) the rationale for this consortium; (ii) characteristics of the studies and women included; and (iii) study methodology to obtain comparable MD data from original re-read films. We also highlight the risk factor heterogeneity captured by such an effort and, thus, the unique insight the pooled study promises to offer through wider exposure ranges, different confounding structures and enhanced power for sub-group analyses.

  11. A GaAs pixel detectors-based digital mammographic system: Performances and imaging tests results

    NASA Astrophysics Data System (ADS)

    Annovazzi, A.; Amendolia, S. R.; Bigongiari, A.; Bisogni, M. G.; Catarsi, F.; Cesqui, F.; Cetronio, A.; Colombo, F.; Delogu, P.; Fantacci, M. E.; Gilberti, A.; Lanzieri, C.; Lavagna, S.; Novelli, M.; Passuello, G.; Paternoster, G.; Pieracci, M.; Poletti, M.; Quattrocchi, M.; Rosso, V.; Stefanini, A.; Testa, A.; Venturelli, L.

    2007-06-01

    The prototype presented in this paper is based on GaAs pixel detectors read-out by the PCC/MEDIPIX I circuit. The active area of a sensor is about 1 cm 2 therefore to cover the typical irradiation field used in mammography (18×24 cm 2), 18 GaAs detection units have been organized in two staggered rows of nine chips each and moved by a stepper motor in the orthogonal direction. The system is integrated in a mammographic equipment which comprehends the X-ray tube, the bias and data acquisition systems and the PC-based control system. The prototype has been developed in the framework of the Integrated Mammographic Imaging (IMI) project, an industrial research activity aiming to develop innovative instrumentation for morphologic and functional imaging. The project has been supported by the Italian Ministry of Education, University and Research (MIUR) and by five Italian High Tech companies, Alenia Marconi Systems (AMS), CAEN, Gilardoni, LABEN and Poli.Hi.Tech., in collaboration with the universities of Ferrara, Roma "La Sapienza", Pisa and the Istituto Nazionale di Fisica Nucleare (INFN). In this paper, we report on the electrical characterization and the first imaging test results of the digital mammographic system. To assess the imaging capability of such a detector we have built a phantom, which simulates the breast tissue with malignancies. The radiographs of the phantom, obtained by delivering an entrance dose of 4.8 mGy, have shown particulars with a measured contrast below 1%.

  12. International Consortium on Mammographic Density: Methodology and Population Diversity captured across 22 Countries

    PubMed Central

    McCormack, Valerie A.; Burton, Anya; dos-Santos-Silva, Isabel; Hipwell, John H.; Dickens, Caroline; Salem, Dorria; Kamal, Rasha; Hartman, Mikael; Ling Lee, Charmaine Pei; Chia, Kee-Seng; Ozmen, Vahit; Aribal, Mustafa Erkin; Flugelman, Anath Arzee; Lajous, Martín; Lopez-Riduara, Ruy; Rice, Megan; Romieu, Isabelle; Ursin, Giske; Qureshi, Samera; Ma, Huiyan; Lee, Eunjung; van Gils, Carla H.; Wanders, Johanna O.P.; Vinayak, Sudhir; Ndumia, Rose; Allen, Steve; Vinnicombe, Sarah; Moss, Sue; Lee, Jong Won; Kim, Jisun; Pereira, Ana; Garmendia, Maria Luisa; Sirous, Reza; Sirous, Mehri; Peplonska, Beata; Bukowska, Agnieszka; Tamimi, Rulla M.; Bertrand, Kimberly; Nagata, Chisato; Kwong, Ava; Vachon, Celine; Scott, Christopher; Perez-Gomez, Beatriz; Pollan, Marina; Maskarinec, Gertraud; Giles, Graham; Hopper, John; Stone, Jennifer; Rajaram, Nadia; Teo, Soo-Hwang; Mariapun, Shivaani; Yaffe, Martin J.; Schüz, Joachim; Chiarelli, Anna; Linton, Linda; Boyd, Norman F.

    2015-01-01

    Mammographic density (MD) is a quantitative trait, measurable in all women, and is among the strongest markers of breast cancer risk. The population-based epidemiology of MD has revealed genetic, lifestyle and societal/environmental determinants, but studies have largely been conducted in women with similar westernized lifestyles living in countries with high breast cancer incidence rates. To benefit from the heterogeneity in risk factors and their combinations worldwide, we created an International Consortium on Mammographic Density (ICMD) to pool individual-level epidemiological and MD data from general population studies worldwide. ICMD aims to characterize determinants of MD more precisely, and to evaluate whether they are consistent across populations worldwide. We included 11755 women, from 27 studies in 22 countries, on whom individual-level risk factor data were pooled and original mammographic images were re-read for ICMD by a core team to obtain standardized comparable MD data. In the present article, we present (i) the rationale for this consortium; (ii) characteristics of the studies and women included; and (iii) study methodology to obtain comparable MD data from original re-read films. We also highlight the risk factor heterogeneity captured by such an effort and, thus, the unique insight the pooled study promises to offer through wider exposure ranges, different confounding structures and enhanced power for sub-group analyses. PMID:26724463

  13. Diagnosis of breast cancer in light microscopic and mammographic images textures using relative entropy via kernel estimation.

    PubMed

    Korkmaz, Sevcan Aytac; Korkmaz, Mehmet Fatih; Poyraz, Mustafa

    2016-04-01

    The aim of this article was to provide early detection of breast cancer by using both mammography and histopathology images of the same patient. When the studies in the literature are examined, it is seen that the mammography and histopathology images of the same patient are not used together for early diagnosis of breast cancer. Mammographic and microscopic images can be limited when using only one of them for the early detection of the breast cancer. Therefore, multi-modality solutions that give more accuracy results than single solutions have been realized in this paper. 3 × 50 microscopic (histopathology) and 3 × 50 mammography image sets have been taken from Firat University Medicine Faculty Pathology and Radiology Laboratories, respectively. Optimum feature space has been obtained by minimum redundancy and maximum relevance via mutual information method applying to the 3 × 50 microscopic and mammography images. Then, probabilistic values of suspicious lesions in the image for selected features have been found by exponential curve fitting. Jensen Shannon, Hellinger, and Triangle measurements have been used for the diagnosis of breast cancer. It has been proved that these measures have been related to each other. Weight values for selected each feature have been found using these measures. These weight values have been used in object function. Afterward, histopathology and mammography images have been classified as normal, malign, and benign utilizing object function. In the result of this classifier, the accuracy of diagnosis of breast cancer has been estimated probabilistically. Furthermore, classifications have been probabilistically visualized on a pie chart. Consequently, the performances of Jensen Shannon, Hellinger, and Triangle measures have been compared with ROC analysis using histopathology and mammography test images. It has been observed that Jensen Shannon measure has higher performance than Hellinger and Triangle measures. Accuracy rates of

  14. Pregnancy-like (pseudolactational) hyperplasia: a primary diagnosis in mammographically detected lesions of the breast and its relationship to cystic hypersecretory hyperplasia.

    PubMed

    Shin, S J; Rosen, P P

    2000-12-01

    Pregnancy-like (pseudolactational) hyperplasia (PLH) has long been recognized as an incidental finding in breast biopsies performed for various clinically detected benign and malignant conditions. The histologic features of PLH have been well described, including some instances exhibiting cytologic and structural atypia. The presence of calcifications in these lesions was rarely mentioned and was considered to be of little consequence. More recently, however, calcifications in PLH have become the target of needle localization and needle core biopsies. The authors report 12 instances in which PLH was the primary diagnosis in biopsy specimens obtained for radiographic abnormalities, usually calcifications. Six of 12 procedures (50.0%) were performed for mammographically detected calcifications, four cases for a mass, one for an "abnormal mammogram," and one for galactorrhea. Calcifications were present in PLH in 10 biopsies, in benign terminal ducts in one specimen, and were not identified histologically in the remaining specimen. In most instances, calcifications associated with PLH had smooth round or lobulated contours and distinctive, internal, unevenly spaced laminations. Cystic hypersecretory hyperplasia (CHH) was present in five specimens. In four of the five specimens, CHH merged with PLH (PLH/CHH). Four of 12 specimens (33.3%) showed atypia within foci of PLH/CHH. PLH should be recognized as a primary diagnosis in breast biopsies for mammographically detected abnormalities such as calcifications. Some calcifications associated with PLH have a distinctive histologic appearance, and their recognition can aid in the diagnosis of PLH. Additional cases of PLH/CHH must be studied to ascertain the clinical significance, if any, of this previously undescribed entity. The precancerous significance of PLH/CHH and of PLH with atypia has not been determined. In most instances, surgical excision would be prudent if PLH/ CHH or PLH with atypia is present in a needle core

  15. Development of a sampling strategy and sample size calculation to estimate the distribution of mammographic breast density in Korean women.

    PubMed

    Jun, Jae Kwan; Kim, Mi Jin; Choi, Kui Son; Suh, Mina; Jung, Kyu-Won

    2012-01-01

    Mammographic breast density is a known risk factor for breast cancer. To conduct a survey to estimate the distribution of mammographic breast density in Korean women, appropriate sampling strategies for representative and efficient sampling design were evaluated through simulation. Using the target population from the National Cancer Screening Programme (NCSP) for breast cancer in 2009, we verified the distribution estimate by repeating the simulation 1,000 times using stratified random sampling to investigate the distribution of breast density of 1,340,362 women. According to the simulation results, using a sampling design stratifying the nation into three groups (metropolitan, urban, and rural), with a total sample size of 4,000, we estimated the distribution of breast density in Korean women at a level of 0.01% tolerance. Based on the results of our study, a nationwide survey for estimating the distribution of mammographic breast density among Korean women can be conducted efficiently.

  16. Genetic variation in Transforming Growth Factor beta 1 and mammographic density in Singapore Chinese women

    PubMed Central

    Lee, Eunjung; Van den Berg, David; Hsu, Chris; Ursin, Giske; Koh, Woon-Puay; Yuan, Jian-Min; Stram, Daniel O.; Yu, Mimi C.; Wu, Anna H.

    2013-01-01

    Transforming growth factor-beta (TGF-β) plays a critical role in normal mammary development and morphogenesis. Decreased TGF-β signaling has been associated with increased mammographic density. Percent mammographic density (PMD) adjusted for age and body mass index (BMI) is a strong risk factor and predictor of breast cancer risk. PMD is highly heritable, but few genetic determinants have been identified. We investigated the association between genetic variation in TGFB1 and PMD using a cross-sectional study of 2,038 women who were members of the population-based Singapore Chinese Health Study cohort. We assessed PMD using a computer-assisted method. We used linear regression to examine the association between 9 tagging SNPs of TGFB1 and PMD and their interaction with parity, adjusting for age, BMI, and dialect group. We calculated ‘P-values adjusted for correlated tests’ (PACT) to account for multiple testing. The strongest association was observed for rs2241716. Adjusted PMD was higher by 1.5% per minor allele (PACT =0.04). When stratifying by parity, this association was limited to nulliparous women. For nulliparous women, adjusted PMD was higher by 8.6% per minor allele (PACT=0.003; P for interaction with parity=0.002). Three additional TGFB1 tagging SNPs, which were in linkage disequilibrium with rs2241716, were statistically significantly associated with adjusted PMD (PACT<0.05) for nulliparous women. However, none of these three SNPs showed statistically significant association after adjusting for rs2241716. Our data support that TGFB1 genetic variation may be an important genetic determinant of mammographic density measure that predicts breast cancer risk, particularly in nulliparous women. PMID:23333936

  17. Metabolic syndrome, insulin resistance, and mammographic density in pre- and postmenopausal women.

    PubMed

    Kim, Bo-Kyoung; Chang, Yoosoo; Ahn, Jiin; Jung, Hyun-Suk; Kim, Chan-Won; Yun, Kyung Eun; Kwon, Min-Jung; Suh, Byung-Seong; Chung, Eun Chul; Shin, Hocheol; Ryu, Seungho

    2015-09-01

    Little is known about the association of metabolic syndrome (MetS) or insulin resistance (IR) with mammographic density, a strong risk factor for breast cancer. The goal of this study was to evaluate these associations in pre- and postmenopausal women. A cross-sectional study was performed in 73,974 adult women who underwent a comprehensive health screening examination that included a mammogram between 2011 and 2013 (mean age 42.6 years). MetS was defined according to the modified National Cholesterol Education Program Adult Treatment Panel III. IR was assessed with the homeostasis model assessment-insulin resistance (HOMA-IR). Adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for dense breast were estimated using logistic regression models after adjustment for potential confounders. In premenopausal women, MetS and all its components except waist circumference were associated with dense breast. After adjustment for potential confounders, the OR (95% CI) for dense breast in women with MetS compared with those without MetS was 1.22 (1.06-1.39). In postmenopausal women, however, there was positive but non-significant association between MetS and dense breast. In both pre- and postmenopausal women, high blood glucose and IR were positively associated with dense breast. The OR (95% CI) for dense breast between the highest and lowest quartiles of HOMA-IR was 1.29 (1.20-1.39) for premenopausal women and 1.44 (1.05-1.97) for postmenopausal women. In a large sample of Korean women, MetS and IR were associated with mammographic dense breast, demonstrating that IR, a potentially modifiable risk factor, may increase breast cancer risk, possibly through high mammographic density.

  18. Varying performance in mammographic interpretation across two countries: Do results indicate reader or population variances?

    NASA Astrophysics Data System (ADS)

    Soh, BaoLin P.; Lee, Warwick B.; Wong, Jill; Sim, Llewellyn; Hillis, Stephen L.; Tapia, Kriscia A.; Brennan, Patrick C.

    2016-03-01

    Aim: To compare the performance of Australian and Singapore breast readers interpreting a single test-set that consisted of mammographic examinations collected from the Australian population. Background: In the teleradiology era, breast readers are interpreting mammographic examinations from different populations. The question arises whether two groups of readers with similar training backgrounds, demonstrate the same level of performance when presented with a population familiar only to one of the groups. Methods: Fifty-three Australian and 15 Singaporean breast radiologists participated in this study. All radiologists were trained in mammogram interpretation and had a median of 9 and 15 years of experience in reading mammograms respectively. Each reader interpreted the same BREAST test-set consisting of sixty de-identified mammographic examinations arising from an Australian population. Performance parameters including JAFROC, ROC, case sensitivity as well as specificity were compared between Australian and Singaporean readers using a Mann Whitney U test. Results: A significant difference (P=0.036) was demonstrated between the JAFROC scores of the Australian and Singaporean breast radiologists. No other significant differences were observed. Conclusion: JAFROC scores for Australian radiologists were higher than those obtained by the Singaporean counterparts. Whilst it is tempting to suggest this is down to reader expertise, this may be a simplistic explanation considering the very similar training and audit backgrounds of the two populations of radiologists. The influence of reading images that are different from those that radiologists normally encounter cannot be ruled out and requires further investigation, particularly in the light of increasing international outsourcing of radiologic reporting.

  19. Clinically and mammographically occult breast lesions: detection and classification with high-resolution sonography.

    PubMed

    Buchberger, W; Niehoff, A; Obrist, P; DeKoekkoek-Doll, P; Dünser, M

    2000-08-01

    With recent significant advances in ultrasound technology, the potential of high-resolution sonography to improve the sensitivity of cancer diagnosis in women with dense breasts has become a matter of interest for breast imagers. To determine how often physician-performed high-resolution sonography can detect nonpalpable breast cancers that are not revealed by mammography, 8,970 women with breast density grades 2 through 4 underwent high-resolution sonography as an adjunct to mammography. All sonographically detected, clinically and mammographically occult breast lesions that were not simple cysts were prospectively classified into benign, indeterminate, or malignant categories. Diagnoses were confirmed by ultrasound-guided fine-needle aspiration, core-needle biopsy, or surgical biopsy. In 8,103 women with normal findings at mammography and physical examination, 32 cancers and 330 benign lesions were detected in 273 patients with sonography only. Eight additional cancers were found in 867 patients with a malignant (n = 5) or a benign (n = 3) palpable or mammographically detected index lesion. The overall prevalence of cancers detected with screening sonography was 0.41%, and the proportion of sonographically detected cancers to the total number of nonpalpable cancers was 22%. The mean size of invasive cancers detected only by sonography was 9.1 mm, and was not statistically different from the mean size of invasive cancers detected by mammography. The sensitivity of prospective sonographic classification for malignancy was 100%, and the specificity was 31%. In conclusion, the use of high-resolution sonography as an adjunct to mammography in women with dense breasts may lead to detection of a significant number of otherwise occult cancers that are no different in size from nonpalpable mammographically detected cancers. Prospective classification of these lesions based on sonographic characteristics resulted in an acceptable benign-to-malignant biopsy rate of 6.3:1.

  20. Qualitative Evaluation.

    ERIC Educational Resources Information Center

    Stone, James C., Ed.; James, Raymond A., Ed.

    1981-01-01

    "Qualitative evaluation" is the theme of this issue of the California Journal of Teacher Education. Ralph Tyler states that evaluation is essentially descriptive, and using numbers does not solve basic problems. Martha Elin Vernazza examines the issue of objectivity in history and its implications for evaluation. She posits that the…

  1. Computed tomographic mammography. Diagnosis of mammographically and clinically occult carcinoma of the breast.

    PubMed

    Sibala, J L; Chang, C H; Lin, F; Jewell, W R

    1981-01-01

    If breast cancer can be detected early, while it is still localized and before it can be palpated, the prognosis for cure is excellent. Heretofore, conventional mammography has been the only means available to detect cancer at such an early stage. Two cases of minimal breast carcinoma measuring less than 5 mm in diameter have been detected and correctly diagnosed using computed tomographic mammography (CT/M). Both cases occurred in fatty breasts and were clinically and mammographically occult. These cases demonstrate the value of CT/M in the diagnosis of minimal breast carcinoma that would have been missed otherwise.

  2. [The significance of mammographic symptoms in clinically occult findings].

    PubMed

    de Waal, J C; Steil, B; Baltzer, J; Vaillant, W; Zander, J

    1987-10-01

    The significance of various radiographic signs in 183 patients with clinically occult breast disease is described. 30.6% had a carcinoma of the breast or a carcinoma in situ. The radiological features have varying predictive values and there is variation in the incidence of lymph node metastases. It is considered useful to classify the radiological appearances under the headings of round foci, star-shaped opacities, diffuse opacities, opacities with calcification and groups of micro-calcification. Despite the early diagnosis, 24% of patients already had lymph node metastases.

  3. Combined photoacoustic and ultrasound imaging of human breast in vivo in the mammographic geometry

    NASA Astrophysics Data System (ADS)

    Xie, Zhixing; Lee, Won-Mean; Hooi, Fong Ming; Fowlkes, J. Brian; Pinsky, Renee W.; Mueller, Dean; Wang, Xueding; Carson, Paul L.

    2013-03-01

    This photoacoustic volume imaging (PAVI) system is designed to study breast cancer detection and diagnosis in the mammographic geometry in combination with automated 3D ultrasound (AUS). The good penetration of near-infrared (NIR) light and high receiving sensitivity of a broad bandwidth, 572 element, 2D PVDF array at a low center-frequency of 1MHz were utilized with 20 channel simultaneous acquisition. The feasibility of this system in imaging optically absorbing objects in deep breast tissues was assessed first through experiments on ex vivo whole breasts. The blood filled pseudo lesions were imaged at depths up to 49 mm in the specimens. In vivo imaging of human breasts has been conducted. 3D PAVI image stacks of human breasts were coregistered and compared with 3D ultrasound image stacks of the same breasts. Using the designed system, PAVI shows satisfactory imaging depth and sensitivity for coverage of the entire breast when imaged from both sides with mild compression in the mammographic geometry. With its unique soft tissue contrast and excellent sensitivity to the tissue hemodynamic properties of fractional blood volume and blood oxygenation, PAVI, as a complement to 3D ultrasound and digital tomosynthesis mammography, might well contribute to detection, diagnosis and prognosis for breast cancer.

  4. Bismuth sulfide nanoflowers for detection of X-rays in the mammographic energy range.

    PubMed

    Nambiar, Shruti; Osei, Ernest K; Yeow, John T W

    2015-03-24

    The increased use of diagnostic x-rays, especially in the field of medical radiology, has necessitated a significant demand for high resolution, real-time radiation detectors. In this regard, the photoresponse of bismuth sulfide (Bi2S3), an n-type semiconducting metal chalcogenide, to low energy x-rays has been investigated in this study. In recent years, several types of nanomaterials of Bi2S3 have been widely studied for optoelectronic and thermoelectric applications. However, photoresponse of Bi2S3 nanomaterials for dosimetric applications has not yet been reported. The photosensitivity of Bi2S3 with nanoscale "flower-like" structures was characterized under x-ray tube-potentials typically used in mammographic procedures. Both dark current and photocurrent were measured under varying x-ray doses, field sizes, and bias voltages for each of the tube potentials - 20, 23, 26 and 30 kV. Results show that the Bi2S3 nanoflowers instantaneously responded to even minor changes in the dose delivered. The photoresponse was found to be relatively high (few nA) at bias voltage as low as +1 V, and fairly repeatable for both short and long exposures to mammographic x-rays with minimal or no loss in sensitivity. The overall dose-sensitivity of the Bi2S3 nanoflowers was found to be similar to that of a micro-ionization chamber.

  5. Mammographic density and intake of selected nutrients and vitamins in Norwegian women.

    PubMed

    Qureshi, Samera Azeem; Couto, Elisabeth; Hilsen, Marit; Hofvind, Solveig; Wu, Anna H; Ursin, Giske

    2011-01-01

    Investigating the association between dietary factors and mammographic density (MD) could shed light on the relationship between diet and breast cancer risk. We took advantage of a national mammographic screening program to study the association between intake of nutrients and MD. In this study, we analyzed data of 2,252 postmenopausal women aged 50-69 yr who participated in the Norwegian Breast Cancer Screening Program in 2004. MD was assessed on digitized mammograms using a computer-assisted method. We used multivariate linear regression models to determine least square means of percent and absolute MD. Overall, we observed no associations between MD and intake of total calories, protein, carbohydrates, cholesterol, and dietary fiber. There was a positive borderline statistically significant association between absolute MD and total fat intake (P = 0.10) and between percent MD and intake of saturated fat (P = 0.06). There was no association between MD and intake of calcium, retinol, vitamins A, B12, C, or D, or combined intake of vitamin D and calcium. This study provides some evidence of an association between MD and dietary intake. Our study highlights the importance of adequate adjustments for BMI in studies of diet and MD.

  6. Automated assessment of bilateral breast volume asymmetry as a breast cancer biomarker during mammographic screening

    SciTech Connect

    Williams, Alex C; Hitt, Austin N; Voisin, Sophie; Tourassi, Georgia

    2013-01-01

    The biological concept of bilateral symmetry as a marker of developmental stability and good health is well established. Although most individuals deviate slightly from perfect symmetry, humans are essentially considered bilaterally symmetrical. Consequently, increased fluctuating asymmetry of paired structures could be an indicator of disease. There are several published studies linking bilateral breast size asymmetry with increased breast cancer risk. These studies were based on radiologists manual measurements of breast size from mammographic images. We aim to develop a computerized technique to assess fluctuating breast volume asymmetry in screening mammograms and investigate whether it correlates with the presence of breast cancer. Using a large database of screening mammograms with known ground truth we applied automated breast region segmentation and automated breast size measurements in CC and MLO views using three well established methods. All three methods confirmed that indeed patients with breast cancer have statistically significantly higher fluctuating asymmetry of their breast volumes. However, statistically significant difference between patients with cancer and benign lesions was observed only for the MLO views. The study suggests that automated assessment of global bilateral asymmetry could serve as a breast cancer risk biomarker for women undergoing mammographic screening. Such biomarker could be used to alert radiologists or computer-assisted detection (CAD) systems to exercise increased vigilance if higher than normal cancer risk is suspected.

  7. Combined photoacoustic and acoustic imaging of human breast specimens in the mammographic geometry.

    PubMed

    Xie, Zhixing; Hooi, Fong Ming; Fowlkes, J Brian; Pinsky, Renee W; Wang, Xueding; Carson, Paul L

    2013-11-01

    A photoacoustic volume imaging (PAVI) system was designed to study breast cancer detection and diagnosis in the mammographic geometry in combination with automated 3-D ultrasound (AUS). The goal of the work described here was to validate the design and evaluate its performance in human breast tissues for non-invasive imaging of deeply positioned structures covering such geometry. The good penetration of near-infrared light and high receiving sensitivity of a broad-bandwidth, 572-element, 2-D polyvinylidene fluoride (PVDF) array at a low center frequency of 1 MHz were used with 20 channel simultaneous acquisition. Pseudo-lesions filled with dilute blood were imaged in three human breast specimens at various depths up to 49 mm. With near-infrared light illumination and 256-sample averaging, the extrapolated maximum depth in imaging a 2.4-mm blood-rich lesion with a 3-dB contrast-to-noise ratio in a compressed breast was 54 mm. Three-dimensional photoacoustic volume image stacks of the breasts were co-registered with 3-D ultrasound image stacks, suggesting for the first time that PAVI, based on the intrinsic tissue contrast, can visualize tissue interfaces other than those with blood, including the inner skin surface and connective tissue sheets. With the designed system, PAVI revealed satisfactory imaging depth and sensitivity for coverage of the entire breast when imaged from both sides in the mammographic geometry with mild compression.

  8. Stereoscopic representation of the breast from two mammographic view with external markers

    NASA Astrophysics Data System (ADS)

    Kallergi, Maria; Manohar, Anand

    2003-05-01

    A new breast imaging technique has been develoepd and tested for the stereoscopic representation of the breast. The method uses markers at specific locations on the breast surface and standard mammographic projections and was tested with an anthropomorphic phantom containing five mass-like objects at locations determined by a CT scan. The phantom was imaged with a GE Senographe 2000D digital system with and without the markers. The algorithm's modules included: 1) Breast area segmentation; 2) Pectoral muscle segmentation; 3) Registration and alignment of the mammographic projections based on selected reference points; 4) Breast volume estimation basdd on volume conservation principle during compression and shape definition using surface points; 5) 3D lesion(s) localization and representation. An interactive, ILD-based, graphical interface was also developed for the stereoscopic display of the breast. The reconstruction algorithm assumed that the breast shrinks and stretches uniformly when compression is applied and removed. The relative movement of the markers after compression allowed more accurate estimation of the shrinking and stretching of the surface offering a relatively simple and practical way to improve volume estimation and surface reconstruction. Such stereoscopic representation of the breast and associated findings may improve radiological interpretation and physical examinations for breast cancer diagnosis.

  9. Identification of a novel percent mammographic density locus at 12q24.

    PubMed

    Stevens, Kristen N; Lindstrom, Sara; Scott, Christopher G; Thompson, Deborah; Sellers, Thomas A; Wang, Xianshu; Wang, Alice; Atkinson, Elizabeth; Rider, David N; Eckel-Passow, Jeanette E; Varghese, Jajini S; Audley, Tina; Brown, Judith; Leyland, Jean; Luben, Robert N; Warren, Ruth M L; Loos, Ruth J F; Wareham, Nicholas J; Li, Jingmei; Hall, Per; Liu, Jianjun; Eriksson, Louise; Czene, Kamila; Olson, Janet E; Pankratz, V Shane; Fredericksen, Zachary; Diasio, Robert B; Lee, Adam M; Heit, John A; DeAndrade, Mariza; Goode, Ellen L; Vierkant, Robert A; Cunningham, Julie M; Armasu, Sebastian M; Weinshilboum, Richard; Fridley, Brooke L; Batzler, Anthony; Ingle, James N; Boyd, Norman F; Paterson, Andrew D; Rommens, Johanna; Martin, Lisa J; Hopper, John L; Southey, Melissa C; Stone, Jennifer; Apicella, Carmel; Kraft, Peter; Hankinson, Susan E; Hazra, Aditi; Hunter, David J; Easton, Douglas F; Couch, Fergus J; Tamimi, Rulla M; Vachon, Celine M

    2012-07-15

    Percent mammographic density adjusted for age and body mass index (BMI) is one of the strongest risk factors for breast cancer and has a heritable component that remains largely unidentified. We performed a three-stage genome-wide association study (GWAS) of percent mammographic density to identify novel genetic loci associated with this trait. In stage 1, we combined three GWASs of percent density comprised of 1241 women from studies at the Mayo Clinic and identified the top 48 loci (99 single nucleotide polymorphisms). We attempted replication of these loci in 7018 women from seven additional studies (stage 2). The meta-analysis of stage 1 and 2 data identified a novel locus, rs1265507 on 12q24, associated with percent density, adjusting for age and BMI (P = 4.43 × 10(-8)). We refined the 12q24 locus with 459 additional variants (stage 3) in a combined analysis of all three stages (n = 10 377) and confirmed that rs1265507 has the strongest association in the 12q24 region (P = 1.03 × 10(-8)). Rs1265507 is located between the genes TBX5 and TBX3, which are members of the phylogenetically conserved T-box gene family and encode transcription factors involved in developmental regulation. Understanding the mechanism underlying this association will provide insight into the genetics of breast tissue composition.

  10. Bismuth Sulfide Nanoflowers for Detection of X-rays in the Mammographic Energy Range

    PubMed Central

    Nambiar, Shruti; Osei, Ernest K.; Yeow, John T. W.

    2015-01-01

    The increased use of diagnostic x-rays, especially in the field of medical radiology, has necessitated a significant demand for high resolution, real-time radiation detectors. In this regard, the photoresponse of bismuth sulfide (Bi2S3), an n-type semiconducting metal chalcogenide, to low energy x-rays has been investigated in this study. In recent years, several types of nanomaterials of Bi2S3 have been widely studied for optoelectronic and thermoelectric applications. However, photoresponse of Bi2S3 nanomaterials for dosimetric applications has not yet been reported. The photosensitivity of Bi2S3 with nanoscale “flower-like” structures was characterized under x-ray tube-potentials typically used in mammographic procedures. Both dark current and photocurrent were measured under varying x-ray doses, field sizes, and bias voltages for each of the tube potentials – 20, 23, 26 and 30 kV. Results show that the Bi2S3 nanoflowers instantaneously responded to even minor changes in the dose delivered. The photoresponse was found to be relatively high (few nA) at bias voltage as low as +1 V, and fairly repeatable for both short and long exposures to mammographic x-rays with minimal or no loss in sensitivity. The overall dose-sensitivity of the Bi2S3 nanoflowers was found to be similar to that of a micro-ionization chamber. PMID:25801531

  11. Automatic detection of regions of interest in mammographic images

    NASA Astrophysics Data System (ADS)

    Cheng, Erkang; Ling, Haibin; Bakic, Predrag R.; Maidment, Andrew D. A.; Megalooikonomou, Vasileios

    2011-03-01

    This work is a part of our ongoing study aimed at comparing the topology of anatomical branching structures with the underlying image texture. Detection of regions of interest (ROIs) in clinical breast images serves as the first step in development of an automated system for image analysis and breast cancer diagnosis. In this paper, we have investigated machine learning approaches for the task of identifying ROIs with visible breast ductal trees in a given galactographic image. Specifically, we have developed boosting based framework using the AdaBoost algorithm in combination with Haar wavelet features for the ROI detection. Twenty-eight clinical galactograms with expert annotated ROIs were used for training. Positive samples were generated by resampling near the annotated ROIs, and negative samples were generated randomly by image decomposition. Each detected ROI candidate was given a confidences core. Candidate ROIs with spatial overlap were merged and their confidence scores combined. We have compared three strategies for elimination of false positives. The strategies differed in their approach to combining confidence scores by summation, averaging, or selecting the maximum score.. The strategies were compared based upon the spatial overlap with annotated ROIs. Using a 4-fold cross-validation with the annotated clinical galactographic images, the summation strategy showed the best performance with 75% detection rate. When combining the top two candidates, the selection of maximum score showed the best performance with 96% detection rate.

  12. HCG blood test - qualitative

    MedlinePlus

    ... qualitative; Serum HCG - qualitative; HCG in blood serum - qualitative ... Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Elsevier Saunders; 2011:chap ...

  13. Journal club: molecular breast imaging at reduced radiation dose for supplemental screening in mammographically dense breasts.

    PubMed

    Rhodes, Deborah J; Hruska, Carrie B; Conners, Amy Lynn; Tortorelli, Cindy L; Maxwell, Robert W; Jones, Katie N; Toledano, Alicia Y; O'Connor, Michael K

    2015-02-01

    OBJECTIVE. The purpose of this study was to assess the diagnostic performance of supplemental screening molecular breast imaging (MBI) in women with mammographically dense breasts after system modifications to permit radiation dose reduction. SUBJECTS AND METHODS. A total of 1651 asymptomatic women with mammographically dense breasts on prior mammography underwent screening mammography and adjunct MBI performed with 300-MBq (99m)Tc-sestamibi and a direct-conversion (cadmium zinc telluride) gamma camera, both interpreted independently. The cancer detection rate, sensitivity, specificity, and positive predictive value of biopsies performed (PPV3) were determined. RESULTS. In 1585 participants with a complete reference standard, 21 were diagnosed with cancer: two detected by mammography only, 14 by MBI only, three by both modalities, and two by neither. Of 14 participants with cancers detected only by MBI, 11 had invasive disease (median size, 0.9 cm; range, 0.5-4.1 cm). Nine of 11 (82%) were node negative, and two had bilateral cancers. With the addition of MBI to mammography, the overall cancer detection rate (per 1000 screened) increased from 3.2 to 12.0 (p < 0.001) (supplemental yield 8.8). The invasive cancer detection rate increased from 1.9 to 8.8 (p < 0.001) (supplemental yield 6.9), a relative increase of 363%, while the change in DCIS detection was not statistically significant (from 1.3 to 3.2, p =0.250). For mammography alone, sensitivity was 24%; specificity, 89%; and PPV3, 25%. For the combination, sensitivity was 91% (p < 0.001); specificity, 83% (p < 0.001); and PPV3, 28% (p = 0.70). The recall rate increased from 11.0% with mammography alone to 17.6% (p < 0.001) for the combination; the biopsy rate increased from 1.3% for mammography alone to 4.2% (p < 0.001). CONCLUSION. When added to screening mammography, MBI performed using a radiopharmaceutical activity acceptable for screening (effective dose 2.4 mSv) yielded a supplemental cancer detection rate

  14. Increased COX-2 expression in epithelial and stromal cells of high mammographic density tissues and in a xenograft model of mammographic density.

    PubMed

    Chew, G L; Huo, C W; Huang, D; Hill, P; Cawson, J; Frazer, H; Hopper, J L; Haviv, I; Henderson, M A; Britt, K; Thompson, E W

    2015-08-01

    Mammographic density (MD) adjusted for age and body mass index is one of the strongest known risk factors for breast cancer. Given the high attributable risk of MD for breast cancer, chemoprevention with a safe and available agent that reduces MD and breast cancer risk would be beneficial. Cox-2 has been implicated in MD-related breast cancer risk, and was increased in stromal cells in high MD tissues in one study. Our study assessed differential Cox-2 expression in epithelial and stromal cells in paired samples of high and low MD human breast tissue, and in a validated xenograft biochamber model of MD. We also examined the effects of endocrine treatment upon Cox-2 expression in high and low MD tissues in the MD xenograft model. Paired high and low MD human breast tissue samples were immunostained for Cox-2, then assessed for differential expression and staining intensity in epithelial and stromal cells. High and low MD human breast tissues were separately maintained in biochambers in mice treated with Tamoxifen, oestrogen or placebo implants, then assessed for percentage Cox-2 staining in epithelial and stromal cells. Percentage Cox-2 staining was greater for both epithelial (p = 0.01) and stromal cells (p < 0.0001) of high compared with low MD breast tissues. In high MD biochamber tissues, percentage Cox-2 staining was greater in stromal cells of oestrogen-treated versus placebo-treated tissues (p = 0.05).

  15. Mammographic density, parity and age at first birth, and risk of breast cancer: an analysis of four case-control studies.

    PubMed

    Woolcott, Christy G; Koga, Karin; Conroy, Shannon M; Byrne, Celia; Nagata, Chisato; Ursin, Giske; Vachon, Celine M; Yaffe, Martin J; Pagano, Ian; Maskarinec, Gertraud

    2012-04-01

    Mammographic density is strongly and consistently associated with breast cancer risk. To determine if this association was modified by reproductive factors (parity and age at first birth), data were combined from four case-control studies conducted in the United States and Japan. To overcome the issue of variation in mammographic density assessment among the studies, a single observer re-read all the mammograms using one type of interactive thresholding software. Logistic regression was used to estimate odds ratios (OR) while adjusting for other known breast cancer risk factors. Included were 1,699 breast cancer cases and 2,422 controls, 74% of whom were postmenopausal. A positive association between mammographic density and breast cancer risk was evident in every group defined by parity and age at first birth (OR per doubling of percent mammographic density ranged between 1.20 and 1.39). Nonetheless, the association appeared to be stronger among nulliparous than parous women (OR per doubling of percent mammographic density = 1.39 vs. 1.24; P interaction = 0.054). However, when examined by study location, the effect modification by parity was apparent only in women from Hawaii and when examined by menopausal status, it was apparent in postmenopausal, but not premenopausal, women. Effect modification by parity was not significant in subgroups defined by body mass index or ethnicity. Adjusting for mammographic density did not attenuate the OR for the association between parity and breast cancer risk by more than 16.4%, suggesting that mammographic density explains only a small proportion of the reduction in breast cancer risk associated with parity. In conclusion, this study did not support the hypothesis that parity modifies the breast cancer risk attributed to mammographic density. Even though an effect modification was found in Hawaiian women, no such thing was found in women from the other three locations.

  16. The Shrinking Breast: An Unusual Mammographic Finding of Invasive Lobular Carcinoma.

    PubMed

    Jafri, Nazia F; Slanetz, Priscilla J

    2007-01-01

    We report two cases of invasive lobular carcinoma of the breast that were initially missed on first mammographic interpretation because of an uncommon, easily overlooked, and unreported imaging presentation. The abnormality in the cases manifested as an apparent decrease in breast glandular tissue volume when compared with the patients' previous mammograms, observed as "shrinking" of the breast on mammography. Invasive lobular carcinoma is considered one of the most difficult subtypes of breast cancer to identify on mammography because the changes that occur are often nonspecific and subtle. Microcalcifications that are usually associated with breast masses on imaging are rarely seen in this subtype of breast cancer. Although magnetic resonance imaging and computer-aided detection have somewhat improved the detection of invasive lobular carcinoma, radiologic and clinical detection remains a challenge.

  17. Mammographic Imaging Studies Using the Monte Carlo Image Simulation-Differential Sampling (MCMIS-DS) Code

    SciTech Connect

    Kuruvilla Verghese

    2002-04-05

    This report summarizes the highlights of the research performed under the 1-year NEER grant from the Department of Energy. The primary goal of this study was to investigate the effects of certain design changes in the Fisher Senoscan mammography system and in the degree of breast compression on the discernability of microcalcifications in calcification clusters often observed in mammograms with tumor lesions. The most important design change that one can contemplate in a digital mammography system to improve resolution of calcifications is the reduction of pixel dimensions of the digital detector. Breast compression is painful to the patient and is though to be a deterrent to women to get routine mammographic screening. Calcification clusters often serve as markers (indicators ) of breast cancer.

  18. Mammographic screening debate on study design: a need to move the field forward.

    PubMed

    Ursin, Giske

    2012-12-12

    The mammographic screening debate has been running for decades. The temperature of this debate is unusually high, and all participants, regardless of viewpoint, seem to have a conflict of interest. Another unusual aspect of this debate is the focus on study design, and in particular on designs that some think exceeded their usefulness decades ago. What are the questions that remain to be answered in this debate? Are there methodological issues that have not been adequately addressed? Do we have the right tools to provide up-to-date answers to how women can best protect themselves against dying from breast cancer? This commentary discusses some of the current issues.See related Opinion articles http://www.biomedcentral.com/1741-7015/10/106 and http://www.biomedcentral.com/1741-7015/10/163.

  19. Use of magnetic resonance imaging for detecting clinically and mammographically occult ductal carcinoma in situ.

    PubMed

    Lo, G; Cheung, Polly S Y

    2008-06-01

    We report on two cases where breast magnetic resonance imaging examination changed clinical management. Breast magnetic resonance imaging is now recognised as an indispensable adjunctive examination to mammography and ultrasound. In each of the two cases described, breast magnetic resonance imaging revealed unsuspected, extensive, and mammographically and ultrasonologically occult, ductal carcinoma in situ. In each of these cases, planned breast conserving surgery was changed to mastectomy. The success of breast conservation treatment depends on removal of all tumour with clear margins at the time of surgery. Magnetic resonance imaging is now considered the most sensitive method for evaluating the extent of breast cancer. Breast magnetic resonance imaging has a very high sensitivity for invasive carcinoma (near 100%), and recent studies show its specificity in high-risk patients is between 93 and 99%. Magnetic resonance imaging may well be proven an important adjunctive examination in patients who have dense breasts or extensive fibrocystic change.

  20. Assessment of change in breast density: reader performance using synthetic mammographic images

    NASA Astrophysics Data System (ADS)

    Astley, Sue; Swayamprakasam, Chitra; Berks, Michael; Sergeant, Jamie; Morris, Julie; Wilson, Mary; Barr, Nicky; Boggis, Caroline

    2012-02-01

    A recent study has shown that breast cancer risk can be reduced by taking Tamoxifen, but only if this results in at least a 10% point reduction in mammographic density. When mammographic density is quantified visually, it is impossible to assess reader accuracy using clinical images as the ground truth is unknown. Our aim was to compare three models of assessing density change and to determine reader accuracy in identifying reductions of 10% points or more. We created 100 synthetic, mammogram-like images comprising 50 pairs designed to simulate natural reduction in density within each pair. Model I: individual images were presented to readers and density assessed. Model II: pairs of images were displayed together, with readers assessing density for each image. Model III: pairs of images were displayed together, and readers asked whether there was at least a 10% point reduction in density. Ten expert readers participated. Readers' estimates of percentage density were significantly closer to the truth (6.8%-26.4%) when images were assessed individually rather than in pairs (9.6%-29.8%). Measurement of change was significantly more accurate in Model II than Model I (p<0.005). Detecting density changes of at least 10% points in image pairs, mean accuracy was significantly (p<0.005) lower (58%-88%) when change was calculated from density assessments than in Model III (74%-92%). Our results suggest that where readers need to identify change in density, images should be displayed alongside one another. In our study, less accurate assessors performed better when asked directly about the magnitude of the change.

  1. An assessment of reference exposure in analogic and digital mammographic units

    NASA Astrophysics Data System (ADS)

    Tilly, J. G.; Miguel, C.; Schelin, H. R.; Porto, L. E.; Paschuk, S.; Denyak, V.; Kmiecik, C.

    2014-11-01

    In this study, the incident air kerma (Ki,a), half-value layer (HVL), output and voltage accuracy for 28 mammography services were evaluated. All mammographs had high frequency rectification, a focus-film distance greater than 60 cm, automatic exposure control, a Mo-Mo anode-filter combination, and compression system. Twenty-three evaluations were made of analogic imaging systems and 21 of digital imaging systems, two of which were full field digital mammography units. The Ki,a was measured in the beam radiation with a 6 cm3 ionization chamber, calibrated for a mammography range of energy. A standard American College of Radiology mammographic phantom simulated a skull caudal incidence. The average, minimum, and maximum Ki,a values were 10.13 mGy, 3.92 mGy, and 30.41 mGy, respectively. However, when the analogic and digital systems are analyzed separately in two subsets, the values were 8.13 mGy, 3.92 mGy, and 11.78 mGy for the analogic systems and 12.33 mGy, 5.21 mGy, and 30.41 mGy for the digital systems, respectively. The results show that the Ki,a values found in digital systems were higher than those in analogic systems, highlighting the differences between these acquisition systems. All HVL values, measured in the primary beam at 28 kV were found between 0.33 mm Al and 0.43 mm Al. Although the manufacture time of the equipment was approximately 146 months (~12 years) prior, the variation in output was between 0.071 mGy/mAs and 0.164 mGy/mAs for the entire sample.

  2. Glycemic index, glycemic load and mammographic breast density: the EPIC Florence longitudinal study.

    PubMed

    Masala, Giovanna; Assedi, Melania; Bendinelli, Benedetta; Ermini, Ilaria; Occhini, Daniela; Sieri, Sabina; Brighenti, Furio; Del Turco, Marco Rosselli; Ambrogetti, Daniela; Palli, Domenico

    2013-01-01

    A few studies have evaluated the association between diet and mammographic breast density (MBD) and results are inconsistent. MBD, a well-recognized risk factor for breast cancer, has been proposed as a marker of cumulative exposure to hormones and growth factors. Diets with a high glycemic index (GI) or glycemic load (GL) may increase breast cancer risk, via an effect on the insulin-like growth factor axis. We have investigated the association between carbohydrate intake, GI, GL and MBD in a prospective study. We identified a large series of women, in the frame of the EPIC-Florence cohort, with a mammogram taken five years after enrolment, when detailed information on dietary and lifestyle habits and anthropometric measurements had been collected. Mammograms have been retrieved (1,668, 83%) and MBD assessed according to Wolfe's classification. We compared women with high MBD (P2+DY Wolfe's categories) with those with low MBD (N1+P1) through logistic models adjusted for age, education, body mass index, menopause, number of children, breast feeding, physical activity, non-alcohol energy, fibers, saturated fat and alcohol. A direct association between GL and high MBD emerged in the highest quintile of intake in comparison with the lowest quintile (OR = 1.73, 95%CI 1.13-2.67, p for trend = 0.048) while no association with glycemic index was evident. These results were confirmed after exclusion of women reporting to be on a diet or affected with diabetes, and when Hormone Replacement Therapy at the date of mammographic examination used to assess MBD was considered. The effect was particularly evident among leaner women, although no interaction was found. A positive association was suggested for increasing simple sugar and total carbohydrates intakes limited to the highest quintiles. In this Italian population we observed an association between glycemic load, total and rapidly absorbed carbohydrates and high MBD. These novel results warrant further investigations.

  3. Performance analysis of morphological component analysis (MCA) method for mammograms using some statistical features

    NASA Astrophysics Data System (ADS)

    Gardezi, Syed Jamal Safdar; Faye, Ibrahima; Kamel, Nidal; Eltoukhy, Mohamed Meselhy; Hussain, Muhammad

    2014-10-01

    Early detection of breast cancer helps reducing the mortality rates. Mammography is very useful tool in breast cancer detection. But it is very difficult to separate different morphological features in mammographic images. In this study, Morphological Component Analysis (MCA) method is used to extract different morphological aspects of mammographic images by effectively preserving the morphological characteristics of regions. MCA decomposes the mammogram into piecewise smooth part and the texture part using the Local Discrete Cosine Transform (LDCT) and Curvelet Transform via wrapping (CURVwrap). In this study, simple comparison in performance has been done using some statistical features for the original image versus the piecewise smooth part obtained from the MCA decomposition. The results show that MCA suppresses the structural noises and blood vessels from the mammogram and enhances the performance for mass detection.

  4. Understanding Participatory Action Research: A Qualitative Research Methodology Option

    ERIC Educational Resources Information Center

    MacDonald, Cathy

    2012-01-01

    Participatory Action Research (PAR) is a qualitative research methodology option that requires further understanding and consideration. PAR is considered democratic, equitable, liberating, and life-enhancing qualitative inquiry that remains distinct from other qualitative methodologies (Kach & Kralik, 2006). Using PAR, qualitative features of an…

  5. A method for 3D electron density imaging using single scattered x-rays with application to mammographic screening.

    PubMed

    Van Uytven, Eric; Pistorius, Stephen; Gordon, Richard

    2008-10-07

    Screening mammography is the current standard in detecting breast cancer. However, its fundamental disadvantage is that it projects a 3D object into a 2D image. Small lesions are difficult to detect when superimposed over layers of normal, heterogeneous tissue. In this work, we examine the potential of single scattered photon electron density imaging in a mammographic environment. Simulating a low-energy (<20 keV) scanning pencil beam, we have developed an algorithm capable of producing 3D electron density images from a single projection. We have tested the algorithm by imaging parts of a simulated mammographic accreditation phantom containing lesions of various sizes. The results indicate that the group of imaged lesions differ significantly from background breast tissue (p<0.005), confirming that electron density imaging may be a useful diagnostic test for the presence of breast cancer.

  6. Digital versus screen-film mammography: impact of mammographic density and hormone therapy on breast cancer detection.

    PubMed

    Chiarelli, Anna M; Prummel, Maegan V; Muradali, Derek; Shumak, Rene S; Majpruz, Vicky; Brown, Patrick; Jiang, Hedy; Done, Susan J; Yaffe, Martin J

    2015-11-01

    Most studies that have examined the effects of mammographic density and hormone therapy use on breast cancer detection have included screen-film mammography. This study further examines this association in post-menopausal women screened by digital mammography. Approved by the University of Toronto Research Ethics Board, this study identified 688,418 women of age 50-74 years screened with digital or screen-film mammography from 2008 to 2009 within the Ontario Breast Screening Program. Of 2993 eligible women with invasive breast cancer, 2450 were contacted and 1421 participated (847 screen-film mammography, 574 digital direct radiography). Mammographic density was measured by study radiologists using the standard BI-RADS classification system and by a computer-assisted method. Information on hormone therapy use was collected by a telephone-administered questionnaire. Logistic regression and two-tailed tests for significance evaluated associations between factors and detection method by mammography type. Women with >75 % radiologist-measured mammographic density compared to those with <25 % were more likely to be diagnosed with an interval than screen-detected cancer, with the difference being greater for those screened with screen-film (OR = 6.40, 95 % CI 2.30-17.85) than digital mammography (OR = 2.41, 95 % CI 0.67-8.58) and aged 50-64 years screened with screen-film mammography (OR = 10.86, 95 % CI 2.96-39.57). Recent former hormone therapy users were also at an increased risk of having an interval cancer with the association being significant for women screened with digital mammography (OR = 2.08, 95 % CI 1.17-3.71). Breast screening using digital mammography lowers the risk of having an interval cancer for post-menopausal women aged 50-64 with greater mammographic density.

  7. Similarity of fibroglandular breast tissue content measured from magnetic resonance and mammographic images and by a mathematical algorithm.

    PubMed

    Nayeem, Fatima; Ju, Hyunsu; Brunder, Donald G; Nagamani, Manubai; Anderson, Karl E; Khamapirad, Tuenchit; Lu, Lee-Jane W

    2014-01-01

    Women with high breast density (BD) have a 4- to 6-fold greater risk for breast cancer than women with low BD. We found that BD can be easily computed from a mathematical algorithm using routine mammographic imaging data or by a curve-fitting algorithm using fat and nonfat suppression magnetic resonance imaging (MRI) data. These BD measures in a strictly defined group of premenopausal women providing both mammographic and breast MRI images were predicted as well by the same set of strong predictor variables as were measures from a published laborious histogram segmentation method and a full field digital mammographic unit in multivariate regression models. We also found that the number of completed pregnancies, C-reactive protein, aspartate aminotransferase, and progesterone were more strongly associated with amounts of glandular tissue than adipose tissue, while fat body mass, alanine aminotransferase, and insulin like growth factor-II appear to be more associated with the amount of breast adipose tissue. Our results show that methods of breast imaging and modalities for estimating the amount of glandular tissue have no effects on the strength of these predictors of BD. Thus, the more convenient mathematical algorithm and the safer MRI protocols may facilitate prospective measurements of BD.

  8. Predicted image quality of a CMOS APS X-ray detector across a range of mammographic beam qualities

    NASA Astrophysics Data System (ADS)

    Konstantinidis, A.

    2015-09-01

    Digital X-ray detectors based on Complementary Metal-Oxide- Semiconductor (CMOS) Active Pixel Sensor (APS) technology have been introduced in the early 2000s in medical imaging applications. In a previous study the X-ray performance (i.e. presampling Modulation Transfer Function (pMTF), Normalized Noise Power Spectrum (NNPS), Signal-to-Noise Ratio (SNR) and Detective Quantum Efficiency (DQE)) of the Dexela 2923MAM CMOS APS X-ray detector was evaluated within the mammographic energy range using monochromatic synchrotron radiation (i.e. 17-35 keV). In this study image simulation was used to predict how the mammographic beam quality affects image quality. In particular, the experimentally measured monochromatic pMTF, NNPS and SNR parameters were combined with various mammographic spectral shapes (i.e. Molybdenum/Molybdenum (Mo/Mo), Rhodium/Rhodium (Rh/Rh), Tungsten/Aluminium (W/Al) and Tungsten/Rhodium (W/Rh) anode/filtration combinations at 28 kV). The image quality was measured in terms of Contrast-to-Noise Ratio (CNR) using a synthetic breast phantom (4 cm thick with 50% glandularity). The results can be used to optimize the imaging conditions in order to minimize patient's Mean Glandular Dose (MGD).

  9. Genome-wide association study identifies multiple loci associated with both mammographic density and breast cancer risk.

    PubMed

    Lindström, Sara; Thompson, Deborah J; Paterson, Andrew D; Li, Jingmei; Gierach, Gretchen L; Scott, Christopher; Stone, Jennifer; Douglas, Julie A; dos-Santos-Silva, Isabel; Fernandez-Navarro, Pablo; Verghase, Jajini; Smith, Paula; Brown, Judith; Luben, Robert; Wareham, Nicholas J; Loos, Ruth J F; Heit, John A; Pankratz, V Shane; Norman, Aaron; Goode, Ellen L; Cunningham, Julie M; deAndrade, Mariza; Vierkant, Robert A; Czene, Kamila; Fasching, Peter A; Baglietto, Laura; Southey, Melissa C; Giles, Graham G; Shah, Kaanan P; Chan, Heang-Ping; Helvie, Mark A; Beck, Andrew H; Knoblauch, Nicholas W; Hazra, Aditi; Hunter, David J; Kraft, Peter; Pollan, Marina; Figueroa, Jonine D; Couch, Fergus J; Hopper, John L; Hall, Per; Easton, Douglas F; Boyd, Norman F; Vachon, Celine M; Tamimi, Rulla M

    2014-10-24

    Mammographic density reflects the amount of stromal and epithelial tissues in relation to adipose tissue in the breast and is a strong risk factor for breast cancer. Here we report the results from meta-analysis of genome-wide association studies (GWAS) of three mammographic density phenotypes: dense area, non-dense area and percent density in up to 7,916 women in stage 1 and an additional 10,379 women in stage 2. We identify genome-wide significant (P<5 × 10(-8)) loci for dense area (AREG, ESR1, ZNF365, LSP1/TNNT3, IGF1, TMEM184B and SGSM3/MKL1), non-dense area (8p11.23) and percent density (PRDM6, 8p11.23 and TMEM184B). Four of these regions are known breast cancer susceptibility loci, and four additional regions were found to be associated with breast cancer (P<0.05) in a large meta-analysis. These results provide further evidence of a shared genetic basis between mammographic density and breast cancer and illustrate the power of studying intermediate quantitative phenotypes to identify putative disease-susceptibility loci.

  10. Digital Breast Tomosynthesis versus Supplemental Diagnostic Mammographic Views for Evaluation of Noncalcified Breast Lesions

    PubMed Central

    Bandos, Andriy I.; Ganott, Marie A.; Sumkin, Jules H.; Kelly, Amy E.; Catullo, Victor J.; Rathfon, Grace Y.; Lu, Amy H.; Gur, David

    2013-01-01

    Purpose: To compare the diagnostic performance of breast tomosynthesis versus supplemental mammography views in classification of masses, distortions, and asymmetries. Materials and Methods: Eight radiologists who specialized in breast imaging retrospectively reviewed 217 consecutively accrued lesions by using protocols that were HIPAA compliant and institutional review board approved in 182 patients aged 31–60 years (mean, 50 years) who underwent diagnostic mammography and tomosynthesis. The lesions in the cohort included 33% (72 of 217) cancers and 67% (145 of 217) benign lesions. Eighty-four percent (182 of 217) of the lesions were masses, 11% (25 of 217) were asymmetries, and 5% (10 of 217) were distortions that were initially detected at clinical examination in 8% (17 of 217), at mammography in 80% (173 of 217), at ultrasonography (US) in 11% (25 of 217), or at magnetic resonance imaging in 1% (2 of 217). Histopathologic examination established truth in 191 lesions, US revealed a cyst in 12 lesions, and 14 lesions had a normal follow-up. Each lesion was interpreted once with tomosynthesis and once with supplemental mammographic views; both modes included the mediolateral oblique and craniocaudal views in a fully crossed and balanced design by using a five-category Breast Imaging Reporting and Data System (BI-RADS) assessment and a probability-of-malignancy score. Differences between modes were analyzed with a generalized linear mixed model for BI-RADS–based sensitivity and specificity and with modified Obuchowski-Rockette approach for probability-of-malignancy–based area under the receiver operating characteristic (ROC) curve. Results: Average probability-of-malignancy–based area under the ROC curve was 0.87 for tomosynthesis versus 0.83 for supplemental views (P < .001). With tomosynthesis, the false-positive rate decreased from 85% (989 of 1160) to 74% (864 of 1160) (P < .01) for cases that were rated BI-RADS category 3 or higher and from 57% (663 of

  11. The vitamin D pathway and mammographic breast density among postmenopausal women

    PubMed Central

    Sprague, Brian L.; Trentham-Dietz, Amy; Gangnon, Ronald E.; Buist, Diana S. M.; Burnside, Elizabeth S.; Aiello Bowles, Erin J.; Stanczyk, Frank Z.; Sisney, Gale S.; Skinner, Halcyon G.

    2011-01-01

    Laboratory studies have demonstrated that vitamin D has a number of chemopreventive properties, and that these properties may be mediated or modified by other molecules in the vitamin D pathway, such as parathyroid hormone (PTH) or calcium. However, there is little epidemiologic data exploring the effects of vitamin D on breast cancer risk in the context of these other molecules. We examined a panel of molecules in the vitamin D pathway in relation to mammographic breast density, a marker of breast cancer risk, in the Wisconsin Breast Density Study. A total of 238 postmenopausal women (ages 55-70, with no history of postmenopausal hormone use) were enrolled from mammography clinics in Madison, Wisconsin. Subjects provided blood samples that were analyzed for levels of 25-hydroxy vitamin D [25(OH)D], PTH, insulin-like growth factor-1 (IGF1), IGF-binding protein 3 (IGFBP3), retinol, and calcium. Percent breast density was measured using Cumulus software. In age-adjusted analyses there was a positive association between 25(OH)D and percent breast density (P=0.05; mean percent density=11.3% vs. 15.6% for 1st vs. 4th quartile of 25(OH)D). Breast density was inversely associated with PTH (P=0.05; 16.0% vs. 11.4% for Q1 vs. Q4) and positively associated with the IGF-1:IGFBP-3 molar ratio (P=0.02; 11.9% vs. 15.6% for Q1 vs. Q4). However, these associations were all null after further adjustment for body mass index (BMI; P>0.25). The independent relation between 25(OH)D and breast density remained null among subgroups defined by BMI and serum levels of retinol, calcium, and estradiol. These results suggest no strong independent associations between the circulating molecules of the vitamin D pathway and mammographic breast density in postmenopausal women. While it remains possible that vitamin D could influence breast cancer risk, our results suggest that such an effect would be mediated through pathways other than breast density. PMID:21847642

  12. A Novel Automated Mammographic Density Measure and Breast 
Cancer Risk

    PubMed Central

    2012-01-01

    Background Mammographic breast density is a strong breast cancer risk factor but is not used in the clinical setting, partly because of a lack of standardization and automation. We developed an automated and objective measurement of the grayscale value variation within a mammogram, evaluated its association with breast cancer, and compared its performance with that of percent density (PD). Methods Three clinic-based studies were included: a case–cohort study of 217 breast cancer case subjects and 2094 non-case subjects and two case–control studies comprising 928 case subjects and 1039 control subjects and 246 case subjects and 516 control subjects, respectively. Percent density was estimated from digitized mammograms using the computer-assisted Cumulus thresholding program, and variation was estimated from an automated algorithm. We estimated hazards ratios (HRs), odds ratios (ORs), the area under the receiver operating characteristic curve (AUC), and 95% confidence intervals (CIs) using Cox proportional hazards models for the cohort and logistic regression for case–control studies, with adjustment for age and body mass index. We performed a meta-analysis using random study effects to obtain pooled estimates of the associations between the two mammographic measures and breast cancer. All statistical tests were two-sided. Results The variation measure was statistically significantly associated with the risk of breast cancer in all three studies (highest vs lowest quartile: HR = 7.0 [95% CI = 4.6 to 10.4]; OR = 10.7 [95% CI = 7.5 to 15.3]; OR = 2.6 [95% CI = 1.6 to 4.2]; all P trend < .001). In two studies, the risk estimates and AUCs for the variation measure were greater than those for percent density (AUCs for variation = 0.71 and 0.76; AUCs for percent density = 0.65 and 0.65), whereas in the third study, these estimates were similar (AUC for variation = 0.60 and AUC for percent density = 0.61). A meta-analysis of the three studies demonstrated a stronger

  13. Polymorphisms in genes involved in the estrogen pathway and mammographic density

    PubMed Central

    2010-01-01

    Background Single nucleotide polymorphisms (SNPs) in genes involved in the estrogen pathway appear to be associated with breast cancer risk and possibly with mammographic density (MD), but little is known of these associations among premenopausal women. This study examines the association of 11 polymorphisms in five estrogen-related genes (estrogen receptors alpha and beta (ERα, ERβ), 17β-hydroxysteroid dehydrogenase 1 (HSD17B1), catechol-O-methyltransferase (COMT), cytochrome P450 1B1 (CYP1B1)) with premenopausal MD. Effect modification of four estrogen-related factors (parity, age at menarche, hormonal derivatives use and body mass index (BMI)) on this relation is also assessed. Methods Polymorphisms were genotyped in 741 premenopausal Caucasian women whose MD was measured in absolute density (AD, cm2) and percent density using a computer-assisted method. Multivariate linear models were used to examine the associations (Ptrend) and interactions (Pi). Results None of the SNPs showed a statistically significant association with AD. However, each additional rare allele of rs1056836 CYP1B1 was associated with a reduction in AD among nulliparous women (Ptrend = 0.004), while no association was observed among parous women (Ptrend = 0.62; Pi = 0.02). An increase in the number of rare alleles of the HSD17B1 SNP (rs598126 and rs2010750) was associated with an increase in AD among women who never used hormonal derivatives (Ptrend = 0.06 and Ptrend = 0.04, respectively), but with a decrease in AD among past hormonal derivatives users (Ptrend = 0.04; Pi = 0.02 and Ptrend = 0.08; Pi = 0.01, respectively). Moreover, a negative association of rs598126 HSD17B1 SNP with AD was observed among women with higher BMI (>median) (Ptrend = 0.01; Pi = 0.02). A negative association between an increased number of rare alleles of COMT rs4680 SNP and AD was limited to women who never used hormonal derivatives (Ptrend = 0.02; Pi = 0.03) or with late age at menarche (>median) (Ptrend = 0

  14. Talking and Thinking about Qualitative Research

    ERIC Educational Resources Information Center

    Ellis, Carolyn; Bochner, Arthur; Denzin, Norman; Lincoln, Yvonna; Morse, Janice; Pelias, Ronald; Richardson, Laurel

    2008-01-01

    This script comes from an edited transcript of a session titled "Talking and Thinking About Qualitative Research," which was part of the 2006 International Congress of Qualitative Inquiry, held at the University of Illinois at Urbana-Champaign on May 4-6, 2006. This special session featured scholars informally responding to questions about their…

  15. Higher alcohol intake may modify the association between mammographic density and breast cancer: an analysis of three case-control studies.

    PubMed

    Conroy, Shannon M; Koga, Karin; Woolcott, Christy G; Dahl, Timothy; Byrne, Celia; Nagata, Chisato; Ursin, Giske; Yaffe, Martin J; Vachon, Celine M; Maskarinec, Gertraud

    2012-10-01

    Alcohol consumption and mammographic density are established risk factors for breast cancer. This study examined whether the association of mammographic density with breast cancer varies by alcohol intake. Mammographic density was assessed in digitized images for 1207 cases and 1663 controls from three populations (Japan, Hawaii, California) using a computer-assisted method. Associations were estimated by logistic regression. When comparing ever to never drinking, mean density was similar and consumption was not associated with breast cancer risk. However, within the Hawaii/Japan subset, women consuming >1 drink/day had a non-significantly elevated relative risk compared to never drinkers. Also in the Hawaii/Japan population, alcohol intake only modified the association between mammographic density and breast cancer in women consuming >1 drink/day (p(interaction)=0.05) with significant risk estimates of 3.65 and 6.58 for the 2nd and 3rd density tertiles as compared to 1.57 and 1.61 for never drinkers in Hawaii/Japan. Although these findings suggest a stronger association between mammographic density and breast cancer risk for alcohol consumers, the small number of cases requires caution in interpreting the results.

  16. Application of computer-extracted breast tissue texture features in predicting false-positive recalls from screening mammography

    NASA Astrophysics Data System (ADS)

    Ray, Shonket; Choi, Jae Y.; Keller, Brad M.; Chen, Jinbo; Conant, Emily F.; Kontos, Despina

    2014-03-01

    Mammographic texture features have been shown to have value in breast cancer risk assessment. Previous models have also been developed that use computer-extracted mammographic features of breast tissue complexity to predict the risk of false-positive (FP) recall from breast cancer screening with digital mammography. This work details a novel locallyadaptive parenchymal texture analysis algorithm that identifies and extracts mammographic features of local parenchymal tissue complexity potentially relevant for false-positive biopsy prediction. This algorithm has two important aspects: (1) the adaptive nature of automatically determining an optimal number of region-of-interests (ROIs) in the image and each ROI's corresponding size based on the parenchymal tissue distribution over the whole breast region and (2) characterizing both the local and global mammographic appearances of the parenchymal tissue that could provide more discriminative information for FP biopsy risk prediction. Preliminary results show that this locallyadaptive texture analysis algorithm, in conjunction with logistic regression, can predict the likelihood of false-positive biopsy with an ROC performance value of AUC=0.92 (p<0.001) with a 95% confidence interval [0.77, 0.94]. Significant texture feature predictors (p<0.05) included contrast, sum variance and difference average. Sensitivity for false-positives was 51% at the 100% cancer detection operating point. Although preliminary, clinical implications of using prediction models incorporating these texture features may include the future development of better tools and guidelines regarding personalized breast cancer screening recommendations. Further studies are warranted to prospectively validate our findings in larger screening populations and evaluate their clinical utility.

  17. A probabilistic framework for image information fusion with an application to mammographic analysis.

    PubMed

    Velikova, Marina; Lucas, Peter J F; Samulski, Maurice; Karssemeijer, Nico

    2012-05-01

    The recent increased interest in information fusion methods for solving complex problem, such as in image analysis, is motivated by the wish to better exploit the multitude of information, available from different sources, to enhance decision-making. In this paper, we propose a novel method, that advances the state of the art of fusing image information from different views, based on a special class of probabilistic graphical models, called causal independence models. The strength of this method is its ability to systematically and naturally capture uncertain domain knowledge, while performing information fusion in a computationally efficient way. We examine the value of the method for mammographic analysis and demonstrate its advantages in terms of explicit knowledge representation and accuracy (increase of at least 6.3% and 5.2% of true positive detection rates at 5% and 10% false positive rates) in comparison with previous single-view and multi-view systems, and benchmark fusion methods such as naïve Bayes and logistic regression.

  18. Optimizing quality of digital mammographic imaging using Taguchi analysis with an ACR accreditation phantom.

    PubMed

    Chen, Ching-Yuan; Pan, Lung-Fa; Chiang, Fu-Tsai; Yeh, Da-Ming; Pan, Lung-Kwang

    2016-07-03

    This work demonstrated the improvement of the visualization of lesions by modulating the factors of an X-ray mammography imaging system using Taguchi analysis. Optimal combinations of X-ray operating factors in each group of level combination were determined using the Taguchi method, in which all factors were organized into only 18 groups, yielding analytical results with the same confidence as if each factor had been examined independently. The 4 considered operating factors of the X-ray machine were (1) anode material (target), (2) kVp, (3) mAs and (4) field of view (FOV). Each of these factors had 2 or 3 levels. Therefore, 54 (2×3×3×3 = 54) combinations were generated. The optimal settings were Rh as the target, 28 kVp, 80 mAs and 19×23 cm(2) FOV. The grade of exposed mammographic phantom image increased from the automatic exposure control (AEC) setting 70.92 to 72.00 under the optimal setting, meeting the minimum standard (70.00) set by Taiwan's Department of Health. The average glandular dose (AGD) of the exposed phantom, 0.182 cGy, was lower than that, 0.203 cGy, under the AEC setting. The Taguchi method was extremely promising for the design of imaging protocols in clinical diagnosis.

  19. Hemodynamic signature of breast cancer under fractional mammographic compression using a dynamic diffuse optical tomography system

    PubMed Central

    Carp, Stefan A.; Sajjadi, Amir Y.; Wanyo, Christy M.; Fang, Qianqian; Specht, Michelle C.; Schapira, Lidia; Moy, Beverly; Bardia, Aditya; Boas, David A.; Isakoff, Steven J.

    2013-01-01

    Near infrared dynamic diffuse optical tomography measurements of breast hemodynamics during fractional mammographic compression offer a novel contrast mechanism for detecting breast cancer and monitoring chemotherapy. Tissue viscoelastic relaxation during the compression period leads to a slow reduction in the compression force and reveals biomechanical and metabolic differences between healthy and lesion tissue. We measured both the absolute values and the temporal evolution of hemoglobin concentration during 25-35 N of compression for 22 stage II and III breast cancer patients scheduled to undergo neoadjuvant chemotherapy. 17 patients were included in the group analysis (average tumor size 3.2 cm, range: 1.3-5.7 cm). We observed a statistically significant differential decrease in total and oxy-hemoglobin, as well as in hemoglobin oxygen saturation in tumor areas vs. healthy tissue, as early as 30 seconds into the compression period. The hemodynamic contrast is likely driven by the higher tumor stiffness and different viscoelastic relaxation rate, as well as the higher tumor oxygen metabolism rate. PMID:24409390

  20. Increased vitamin D and calcium intake associated with reduced mammographic breast density among premenopausal women.

    PubMed

    Fair, Alecia Malin; Lewis, Toni J; Sanderson, Maureen; Dupont, William D; Fletcher, Sarah; Egan, Kathleen M; Disher, Anthony C

    2015-10-01

    Vitamin D has been identified as a weak protective factor for postmenopausal breast cancer (relative risk, ~0.9), whereas high breast density has been identified as a strong risk factor (relative risk, ~4-6). To test the hypothesis that there is an association between vitamin D intake, but not circulating vitamin D levels, and mammographic breast density among women in our study, we conducted a cross-sectional study of 165 screening mammography patients at Nashville General Hospital's Breast Health Center, a public facility serving medically indigent and underserved women. Dietary and total (dietary plus supplements) vitamin D and calcium intakes were estimated by the Harvard African American Food Frequency Questionnaire, and blood samples were analyzed for 25-hydroxyvitamin D. Average percent breast density for the left and right breasts combined was estimated from digitized films using an interactive thresholding method available through Cumulus software. After statistical adjustment for age, race, and body mass index, the results revealed that there were significant trends of decreasing breast density with increasing vitamin D and calcium intake among premenopausal but not among postmenopausal women. There was no association between serum vitamin D and breast density in premenopausal or postmenopausal women. Confirmation of our findings in larger studies may assist in clarifying the role of vitamin D in breast density.

  1. The effect of skin thickness determined using breast CT on mammographic dosimetry

    SciTech Connect

    Huang Shihying; Boone, John M.; Yang, Kai; Kwan, Alexander L. C.; Packard, Nathan J.

    2008-04-15

    The effect of breast skin thickness on dosimetry in mammography was investigated. Breast computed tomography (CT) acquisition techniques, combined with algorithms designed for determining specific breast metrics, were useful for estimating skin thickness. A radial-geometry edge detection scheme was implemented on coronal reconstructed breast CT (bCT) images to measure the breast skin thickness. Skin thickness of bilateral bCT volume data from 49 women and unilateral bCT volume data from 2 women (10 healthy women and 41 women with BIRADS 4 and 5 diagnoses) was robustly measured with the edge detection scheme. The mean breast skin thickness ({+-}inter-breast standard deviation) was found to be 1.45{+-}0.30 mm. Since most current published normalized glandular dose (D{sub gN}) coefficients are based on the assumption of a 4-mm breast skin thickness, the D{sub gN} values computed with Monte Carlo techniques will increase up to 18% due to the thinner skin layers (e.g., 6-cm 50% glandular breast, 28 kVp Mo-Mo spectrum). The thinner skin dimensions found in this study suggest that the current D{sub gN} values used for mammographic dosimetry lead to a slight underestimate in glandular dose.

  2. Mammographic findings after breast cancer treatment with local excision and definitive irradiation

    SciTech Connect

    Dershaw, D.D.; Shank, B.; Reisinger, S.

    1987-08-01

    Following local excision and definitive irradiation of 163 breast cancers in 160 women, alterations in mammographic patterns were observed for up to 7 years. Skin thickening was observed in 96% of mammograms obtained within 1 year of completing therapy and was most pronounced in women treated with iridium implant, chemotherapy, or axillary dissection. In 76% of mammograms, alterations in the parenchymal pattern, including coarsening of stroma and increased breast density, were seen at 1 year. Neither skin nor parenchymal changes progressed after 1 year. Within 3 years of treatment the parenchymal density, which usually regressed, did not change in all patients. At 3 years skin thickness and the parenchymal pattern had returned to normal in less than 50% of the breasts of these women. Scars developed in approximately one-quarter of women. They were present on the initial post-treatment mammogram and remained unchanged on serial studies. Coarse, benign calcifications also developed in the breasts of about one-quarter of women. Microcalcifications developed in 11 breasts; biopsy specimens of six were benign. Benign microcalcifications may be related to therapy.

  3. Pixelated CdTe detectors to overcome intrinsic limitations of crystal based positron emission mammographs

    NASA Astrophysics Data System (ADS)

    De Lorenzo, G.; Chmeissani, M.; Uzun, D.; Kolstein, M.; Ozsahin, I.; Mikhaylova, E.; Arce, P.; Cañadas, M.; Ariño, G.; Calderón, Y.

    2013-01-01

    A positron emission mammograph (PEM) is an organ dedicated positron emission tomography (PET) scanner for breast cancer detection. State-of-the-art PEMs employing scintillating crystals as detection medium can provide metabolic images of the breast with significantly higher sensitivity and specificity with respect to standard whole body PET scanners. Over the past few years, crystal PEMs have dramatically increased their importance in the diagnosis and treatment of early stage breast cancer. Nevertheless, designs based on scintillators are characterized by an intrinsic deficiency of the depth of interaction (DOI) information from relatively thick crystals constraining the size of the smallest detectable tumor. This work shows how to overcome such intrinsic limitation by substituting scintillating crystals with pixelated CdTe detectors. The proposed novel design is developed within the Voxel Imaging PET (VIP) Pathfinder project and evaluated via Monte Carlo simulation. The volumetric spatial resolution of the VIP-PEM is expected to be up to 6 times better than standard commercial devices with a point spread function of 1 mm full width at half maximum (FWHM) in all directions. Pixelated CdTe detectors can also provide an energy resolution as low as 1.5% FWHM at 511 keV for a virtually pure signal with negligible contribution from scattered events.

  4. Pixelated CdTe detectors to overcome intrinsic limitations of crystal based positron emission mammographs.

    PubMed

    De Lorenzo, G; Chmeissani, M; Uzun, D; Kolstein, M; Ozsahin, I; Mikhaylova, E; Arce, P; Cañadas, M; Ariño, G; Calderón, Y

    2013-01-01

    A positron emission mammograph (PEM) is an organ dedicated positron emission tomography (PET) scanner for breast cancer detection. State-of-the-art PEMs employing scintillating crystals as detection medium can provide metabolic images of the breast with significantly higher sensitivity and specificity with respect to standard whole body PET scanners. Over the past few years, crystal PEMs have dramatically increased their importance in the diagnosis and treatment of early stage breast cancer. Nevertheless, designs based on scintillators are characterized by an intrinsic deficiency of the depth of interaction (DOI) information from relatively thick crystals constraining the size of the smallest detectable tumor. This work shows how to overcome such intrinsic limitation by substituting scintillating crystals with pixelated CdTe detectors. The proposed novel design is developed within the Voxel Imaging PET (VIP) Pathfinder project and evaluated via Monte Carlo simulation. The volumetric spatial resolution of the VIP-PEM is expected to be up to 6 times better than standard commercial devices with a point spread function of 1 mm full width at half maximum (FWHM) in all directions. Pixelated CdTe detectors can also provide an energy resolution as low as 1.5% FWHM at 511 keV for a virtually pure signal with negligible contribution from scattered events.

  5. Pixelated CdTe detectors to overcome intrinsic limitations of crystal based positron emission mammographs

    PubMed Central

    De Lorenzo, G.; Chmeissani, M.; Uzun, D.; Kolstein, M.; Ozsahin, I.; Mikhaylova, E.; Arce, P.; Cañadas, M.; Ariño, G.; Calderón, Y.

    2013-01-01

    A positron emission mammograph (PEM) is an organ dedicated positron emission tomography (PET) scanner for breast cancer detection. State-of-the-art PEMs employing scintillating crystals as detection medium can provide metabolic images of the breast with significantly higher sensitivity and specificity with respect to standard whole body PET scanners. Over the past few years, crystal PEMs have dramatically increased their importance in the diagnosis and treatment of early stage breast cancer. Nevertheless, designs based on scintillators are characterized by an intrinsic deficiency of the depth of interaction (DOI) information from relatively thick crystals constraining the size of the smallest detectable tumor. This work shows how to overcome such intrinsic limitation by substituting scintillating crystals with pixelated CdTe detectors. The proposed novel design is developed within the Voxel Imaging PET (VIP) Pathfinder project and evaluated via Monte Carlo simulation. The volumetric spatial resolution of the VIP-PEM is expected to be up to 6 times better than standard commercial devices with a point spread function of 1 mm full width at half maximum (FWHM) in all directions. Pixelated CdTe detectors can also provide an energy resolution as low as 1.5% FWHM at 511 keV for a virtually pure signal with negligible contribution from scattered events. PMID:23750176

  6. Inter-observer variability within BI-RADS and RANZCR mammographic density assessment schemes

    NASA Astrophysics Data System (ADS)

    Damases, Christine N.; Mello-Thoms, Claudia; McEntee, Mark F.

    2016-03-01

    This study compares variability associated with two visual mammographic density (MD) assessment methods using two separate samples of radiologists. The image test-set comprised of images obtained from 20 women (age 42-89 years). The images were assessed for their MD by twenty American Board of Radiology (ABR) examiners and twenty-six radiologists registered with the Royal Australian and New Zealand College of Radiologists (RANZCR). Images were assessed using the same technology and conditions, however the ABR radiologists used the BI-RADS and the RANZCR radiologists used the RANZCR breast density synoptic. Both scales use a 4-point assessment. The images were then grouped as low- and high-density; low including BIRADS 1 and 2 or RANZCR 1 and 2 and high including BI-RADS 3 and 4 or RANZCR 3 and 4. Four-point BI-RADS and RANZCR showed no or negligible correlation (ρ=-0.029 p<0.859). The average inter-observer agreement on the BI-RADS scale had a Kappa of 0.565; [95% CI = 0.519 - 0.610], and ranged between 0.328-0.669 while the inter-observer agreement using the RANZCR scale had a Kappa of 0.360; [95% CI = 0.308 - 0.412] and a range of 0.078-0.499. Our findings show a wider range of inter-observer variability among RANZCR registered radiologists than the ABR examiners.

  7. Evolution of mammographic image quality in the state of Rio de Janeiro*

    PubMed Central

    Villar, Vanessa Cristina Felippe Lopes; Seta, Marismary Horsth De; de Andrade, Carla Lourenço Tavares; Delamarque, Elizabete Vianna; de Azevedo, Ana Cecília Pedrosa

    2015-01-01

    Objective To evaluate the evolution of mammographic image quality in the state of Rio de Janeiro on the basis of parameters measured and analyzed during health surveillance inspections in the period from 2006 to 2011. Materials and Methods Descriptive study analyzing parameters connected with imaging quality of 52 mammography apparatuses inspected at least twice with a one-year interval. Results Amongst the 16 analyzed parameters, 7 presented more than 70% of conformity, namely: compression paddle pressure intensity (85.1%), films development (72.7%), film response (72.7%), low contrast fine detail (92.2%), tumor mass visualization (76.5%), absence of image artifacts (94.1%), mammography-specific developers availability (88.2%). On the other hand, relevant parameters were below 50% conformity, namely: monthly image quality control testing (28.8%) and high contrast details with respect to microcalcifications visualization (47.1%). Conclusion The analysis revealed critical situations in terms of compliance with the health surveillance standards. Priority should be given to those mammography apparatuses that remained non-compliant at the second inspection performed within the one-year interval. PMID:25987749

  8. Insulin-like growth factor-1, insulin-like growth factor-binding protein-3, growth hormone, and mammographic density in the Nurses' Health Studies.

    PubMed

    Rice, Megan S; Tworoger, Shelley S; Rosner, Bernard A; Pollak, Michael N; Hankinson, Susan E; Tamimi, Rulla M

    2012-12-01

    Higher circulating insulin-like growth factor I (IGF-1) levels have been associated with higher mammographic density among women in some, but not all studies. Also, few studies have examined the association between mammographic density and circulating growth hormone (GH) in premenopausal women. We conducted a cross-sectional study among 783 premenopausal women and 436 postmenopausal women who were controls in breast cancer case-control studies nested in the Nurses' Health Study (NHS) and NHSII. Participants provided blood samples in 1989-1990 (NHS) or in 1996-1999 (NHSII), and mammograms were obtained near the time of blood draw. Generalized linear models were used to assess the associations of IGF-1, IGF-binding protein-3 (IGFBP-3), IGF-1:IGFBP-3 ratio, and GH with percent mammographic density, total dense area, and total non-dense area. Models were adjusted for potential confounders including age and body mass index (BMI), among others. We also assessed whether the associations varied by age or BMI. In both pre- and postmenopausal women, percent mammographic density was not associated with plasma levels of IGF-1, IGFBP-3, or the IGF-1:IGFBP-3 ratio. In addition, GH was not associated with percent density among premenopausal women in the NHSII. Similarly, total dense area and non-dense area were not significantly associated with any of these analytes. In postmenopausal women, IGF-1 was associated with higher percent mammographic density among women with BMI <25 kg/m(2), but not among overweight/obese women. Overall, plasma IGF-1, IGFBP-3, and GH levels were not associated with mammographic density in a sample of premenopausal and postmenopausal women.

  9. Effect of a low-fat, high-carbohydrate dietary intervention on change in mammographic density over menopause.

    PubMed

    Martin, Lisa J; Greenberg, Carolyn V; Kriukov, Valentina; Minkin, Salomon; Jenkins, David J A; Yaffe, Martin; Hislop, Gregory; Boyd, Norman F

    2009-01-01

    We have previously shown that a low-fat dietary intervention for 2 years in women with extensive mammographic density decreased mammographic density to a greater extent than in the control group. Post-hoc analysis indicated that this effect was strongest in women who became postmenopausal during the follow-up period. The purpose of the present study was to determine if this potentially important finding could be confirmed in a new and larger group of subjects with a longer follow-up time. Participants in a low-fat dietary intervention trial who were premenopausal at entry and became postmenopausal during follow-up were examined. Total breast, dense, and non-dense area and percent density were measured in baseline and postmenopause mammograms using a computer-assisted method. Total breast and non dense area increased more in the control group compared to the intervention group (for breast area 2.6 and 0.2 cm(2), respectively; P=0.05, and for non-dense area 10.9 and 8.1 cm(2), respectively; P=0.06). Dense area decreased to a similar degree in both groups (-8.2 and -8.0 cm(2), respectively; P=0.84). Percent density decreased to a slightly greater degree in the control compared to intervention group (-9.4 and -7.8%, respectively, P=0.11). There were no significant differences between study groups after adjustment for weight change. Menopause reduced density to a similar extent in the low-fat diet and control groups. If a low-fat diet reduces breast cancer risk, the effect is unlikely to be through changes in mammographic density at menopause.

  10. Relationship of Terminal Duct Lobular Unit Involution of the Breast with Area and Volume Mammographic Densities

    PubMed Central

    Gierach, Gretchen L.; Patel, Deesha A.; Pfeiffer, Ruth M.; Figueroa, Jonine D.; Linville, Laura; Papathomas, Daphne; Johnson, Jason M.; Chicoine, Rachael E.; Herschorn, Sally D.; Shepherd, John A.; Wang, Jeff; Malkov, Serghei; Vacek, Pamela M.; Weaver, Donald L.; Fan, Bo; Mahmoudzadeh, Amir Pasha; Palakal, Maya; Xiang, Jackie; Oh, Hannah; Horne, Hisani N.; Sprague, Brian L.; Hewitt, Stephen M.; Brinton, Louise A.; Sherman, Mark E.

    2016-01-01

    Elevated mammographic density (MD) is an established breast cancer risk factor. Reduced involution of terminal duct lobular units (TDLUs), the histologic source of most breast cancers, has been associated with higher MD and breast cancer risk. We investigated relationships of TDLU involution with area and volumetric MD, measured throughout the breast and surrounding biopsy targets (peri-lesional). Three measures inversely related to TDLU involution (TDLU count/mm2, median TDLU span, median acini count/TDLU) assessed in benign diagnostic biopsies from 348 women, ages 40–65, were related to MD area (quantified with thresholding software) and volume (assessed with a density phantom) by analysis of covariance, stratified by menopausal status and adjusted for confounders. Among premenopausal women, TDLU count was directly associated with percent peri-lesional MD (P-trend=0.03), but not with absolute dense area/volume. Greater TDLU span was associated with elevated percent dense area/volume (P-trend<0.05) and absolute peri-lesional MD (P=0.003). Acini count was directly associated with absolute peri-lesional MD (P=0.02). Greater TDLU involution (all metrics) was associated with increased nondense area/volume (P-trend≤0.04). Among postmenopausal women, TDLU measures were not significantly associated with MD. Among premenopausal women, reduced TDLU involution was associated with higher area and volumetric MD, particularly in peri-lesional parenchyma. Data indicating that TDLU involution and MD are correlated markers of breast cancer risk suggest that associations of MD with breast cancer may partly reflect amounts of at-risk epithelium. If confirmed, these results could suggest a prevention paradigm based on enhancing TDLU involution and monitoring efficacy by assessing MD reduction. PMID:26645278

  11. Longitudinal Change in Mammographic Density among ER-Positive Breast Cancer Patients Using Tamoxifen.

    PubMed

    Nyante, Sarah J; Sherman, Mark E; Pfeiffer, Ruth M; Berrington de Gonzalez, Amy; Brinton, Louise A; Bowles, Erin J Aiello; Hoover, Robert N; Glass, Andrew; Gierach, Gretchen L

    2016-01-01

    Tamoxifen-associated mammographic density (MD) reductions are linked to improved breast cancer survival. We evaluated MD at six time points to determine the timing of greatest reduction following tamoxifen initiation. We sampled 40 Kaiser Permanente Northwest estrogen receptor (ER)-positive breast cancer patients from a prior study of MD change, according to tamoxifen use duration and age at diagnosis: <4 years tamoxifen and ≤50 years (N = 6) or >50 years (N = 10) old; ≥4 years tamoxifen and ≤50 years (N = 13) or >50 years (N = 11) old. A single reader evaluated percent MD in the contralateral breast on baseline (pre-diagnosis) and five approximately yearly post-diagnostic (T1 to T5) mammograms. Mean MD change was calculated. Interactions with age (≤50 and >50 years), tamoxifen duration (<4 and ≥4 years), and baseline MD (tertiles) were tested in linear regression models. Overall, the largest MD decline occurred by T1 (mean 4.5%) with little additional decline by T5. Declines differed by tertile of baseline MD (Pinteraction < 0.01). In the highest tertile, the largest reduction occurred by T1 (mean 14.9%), with an additional reduction of 3.6% by T5. Changes were smaller in the middle and lowest baseline MD tertiles, with cumulative reductions of 3.0% and 0.4% from baseline to T5, respectively. There were no differences by age (Pinteraction = 0.36) or tamoxifen duration (Pinteraction = 0.42). Among ER-positive patients treated with tamoxifen and surviving ≥5 years, most of the MD reduction occurred within approximately 12 months of tamoxifen initiation, suggesting that MD measurement at a single time point following tamoxifen initiation can identify patients with substantial density declines.

  12. Associated factors with mammographic changes in women undergoing breast cancer screening

    PubMed Central

    de Sant'Ana, Ricardo Soares; Mattos, Jacó Saraiva de Castro; da Silva, Anderson Soares; de Mello, Luanes Marques; Nunes, Altacílio Aparecido

    2016-01-01

    ABSTRACT Objective: To evaluate association of sociodemographic, anthropometric, and epidemiological factors with result of mammogram in women undergoing breast cancer screening. Methods: This is a cross-sectional study with data obtained through interviews, anthropometric measurements, and mammography of 600 women aged 40 to 69 years at the Preventive Medicine Department of Hospital de Câncer de Barretos, Brazil, in 2014. The results of these examinations in the BI-RADS categories 1 and 2 were grouped and classified in this study as normal mammogram outcome, and those of BI-RADS categories 3, 4A, 4B, 4C, and 5 were grouped and classified as altered mammogram outcome. The statistical analysis included the Student's t-test to compare means, as well as odds ratios (OR), with their corresponding 95% confidence intervals (95%CI), to verify an association by means of the multivariate analysis. Results: Of 600 women evaluated, 45% belonged to the age group of 40–49 years-old and 60.2% were classified as BI-RADS category 2. The multivariate analysis showed that women with blood hypertension (OR: 2.64; 95%CI: 1.07–6.49; p<0.05) were more likely to present changes in the mammography, while physical activity was associated with lower chances (OR: 0.30; 95%CI: 0.11–0.81; p<0.05). Conclusion: Hypertensive women undergoing screening mammography are more likely to present mammographic changes, whereas women practicing physical activity have lower chances (70%) of presenting changes in the breast compared with sedentary individuals. PMID:27759819

  13. Vision 20/20: Mammographic breast density and its clinical applications

    SciTech Connect

    Ng, Kwan-Hoong Lau, Susie

    2015-12-15

    Breast density is a strong predictor of the failure of mammography screening to detect breast cancer and is a strong predictor of the risk of developing breast cancer. The many imaging options that are now available for imaging dense breasts show great promise, but there is still the question of determining which women are “dense” and what imaging modality is suitable for individual women. To date, mammographic breast density has been classified according to the Breast Imaging-Reporting and Data System (BI-RADS) categories from visual assessment, but this is known to be very subjective. Despite many research reports, the authors believe there has been a lack of physics-led and evidence-based arguments about what breast density actually is, how it should be measured, and how it should be used. In this paper, the authors attempt to start correcting this situation by reviewing the history of breast density research and the debates generated by the advocacy movement. The authors review the development of breast density estimation from pattern analysis to area-based analysis, and the current automated volumetric breast density (VBD) analysis. This is followed by a discussion on seeking the ground truth of VBD and mapping volumetric methods to BI-RADS density categories. The authors expect great improvement in VBD measurements that will satisfy the needs of radiologists, epidemiologists, surgeons, and physicists. The authors believe that they are now witnessing a paradigm shift toward personalized breast screening, which is going to see many more cancers being detected early, with the use of automated density measurement tools as an important component.

  14. Calorie intake, olive oil consumption and mammographic density among Spanish women

    PubMed Central

    García-Arenzana, Nicolás; Navarrete-Muñoz, Eva María; Lope, Virginia; Moreo, Pilar; Vidal, Carmen; Laso-Pablos, Soledad; Ascunce, Nieves; Casanova-Gómez, Francisco; Sánchez-Contador, Carmen; Santamariña, Carmen; Aragonés, Nuria; Gómez, Beatriz Pérez; Vioque, Jesús; Pollán, Marina

    2014-01-01

    High mammographic density (MD) is one of the main risk factors for development of breast cancer. To date, however, relatively few studies have evaluated the association between MD and diet. In this cross-sectional study, we assessed the association between MD (measured using Boyd's semiquantitative scale with five categories: <10%, 10–25%, 25–50%, 50–75% and >75%) and diet (measured using a food frequency questionnaire validated in a Spanish population) among 3,548 peri- and postmenopausal women drawn from seven breast cancer screening programs in Spain. Multivariate ordinal logistic regression models, adjusted for age, body mass index (BMI), energy intake and protein consumption as well as other confounders, showed an association between greater calorie intake and greater MD [odds ratio (OR) = 1.23; 95% confidence interval (CI) = 1.10-1.38, for every increase of 500 cal/day], yet high consumption of olive oil was nevertheless found to reduce the prevalence of high MD (OR = 0.86;95% CI = 0.76-0.96, for every increase of 22 g/day in olive oil consumption); and, while greater intake of whole milk was likewise associated with higher MD (OR = 1.10; 95%CI 1.00-1.20, for every increase of 200 g/day), higher consumption of protein (OR = 0.89; 95% CI 0.80-1.00, for every increase of 30 g/day) and white meat (p for trend 0.041) was found to be inversely associated with MD. Our study, the largest to date to assess the association between diet and MD, suggests that MD is associated with modifiable dietary factors, such as calorie intake and olive oil consumption. These foods could thus modulate the prevalence of high MD, and important risk marker for breast cancer. PMID:24254818

  15. Mammographic Density and Prediction of Nodal Status in Breast Cancer Patients

    PubMed Central

    Hack, C. C.; Häberle, L.; Geisler, K.; Schulz-Wendtland, R.; Hartmann, A.; Fasching, P. A.; Uder, M.; Wachter, D. L.; Jud, S. M.; Loehberg, C. R.; Lux, M. P.; Rauh, C.; Beckmann, M. W.; Heusinger, K.

    2013-01-01

    Aim: Nodal status remains one of the most important prognostic factors in breast cancer. The cellular and molecular reasons for the spread of tumor cells to the lymph nodes are not well understood and there are only few predictors in addition to tumor size and multifocality that give an insight into additional mechanisms of lymphatic spread. Aim of our study was therefore to investigate whether breast characteristics such as mammographic density (MD) add to the predictive value of the presence of lymph node metastases in patients with primary breast cancer. Methods: In this retrospective study we analyzed primary, metastasis-free breast cancer patients from one breast center for whom data on MD and staging information were available. A total of 1831 patients were included into this study. MD was assessed as percentage MD (PMD) using a semiautomated method and two readers for every patient. Multiple logistic regression analyses with nodal status as outcome were used to investigate the predictive value of PMD in addition to age, tumor size, Ki-67, estrogen receptor (ER), progesterone receptor (PR), grading, histology, and multi-focality. Results: Multifocality, tumor size, Ki-67 and grading were relevant predictors for nodal status. Adding PMD to a prediction model which included these factors did not significantly improve the prediction of nodal status (p = 0.24, likelihood ratio test). Conclusion: Nodal status could be predicted quite well with the factors multifocality, tumor size, Ki-67 and grading. PMD does not seem to play a role in the lymphatic spread of tumor cells. It could be concluded that the amount of extracellular matrix and stromal cell content of the breast which is reflected by MD does not influence the probability of malignant breast cells spreading from the primary tumor to the lymph nodes. PMID:24771910

  16. Mammographic breast density and breast cancer: evidence of a shared genetic basis.

    PubMed

    Varghese, Jajini S; Thompson, Deborah J; Michailidou, Kyriaki; Lindström, Sara; Turnbull, Clare; Brown, Judith; Leyland, Jean; Warren, Ruth M L; Luben, Robert N; Loos, Ruth J; Wareham, Nicholas J; Rommens, Johanna; Paterson, Andrew D; Martin, Lisa J; Vachon, Celine M; Scott, Christopher G; Atkinson, Elizabeth J; Couch, Fergus J; Apicella, Carmel; Southey, Melissa C; Stone, Jennifer; Li, Jingmei; Eriksson, Louise; Czene, Kamila; Boyd, Norman F; Hall, Per; Hopper, John L; Tamimi, Rulla M; Rahman, Nazneen; Easton, Douglas F

    2012-03-15

    Percent mammographic breast density (PMD) is a strong heritable risk factor for breast cancer. However, the pathways through which this risk is mediated are still unclear. To explore whether PMD and breast cancer have a shared genetic basis, we identified genetic variants most strongly associated with PMD in a published meta-analysis of five genome-wide association studies (GWAS) and used these to construct risk scores for 3,628 breast cancer cases and 5,190 controls from the UK2 GWAS of breast cancer. The signed per-allele effect estimates of single-nucleotide polymorphisms (SNP) were multiplied with the respective allele counts in the individual and summed over all SNPs to derive the risk score for an individual. These scores were included as the exposure variable in a logistic regression model with breast cancer case-control status as the outcome. This analysis was repeated using 10 different cutoff points for the most significant density SNPs (1%-10% representing 5,222-50,899 SNPs). Permutation analysis was also conducted across all 10 cutoff points. The association between risk score and breast cancer was significant for all cutoff points from 3% to 10% of top density SNPs, being most significant for the 6% (2-sided P = 0.002) to 10% (P = 0.001) cutoff points (overall permutation P = 0.003). Women in the top 10% of the risk score distribution had a 31% increased risk of breast cancer [OR = 1.31; 95% confidence interval (CI), 1.08-1.59] compared with women in the bottom 10%. Together, our results show that PMD and breast cancer have a shared genetic basis that is mediated through a large number of common variants.

  17. Variation in Inflammatory Cytokine/Growth-Factor Genes and Mammographic Density in Premenopausal Women Aged 50–55

    PubMed Central

    Ozhand, Ali; Lee, Eunjung; Wu, Anna H.; Ellingjord-Dale, Merete; Akslen, Lars A.; McKean-Cowdin, Roberta; Ursin, Giske

    2013-01-01

    Background Mammographic density (MD) has been found to be an independent risk factor for breast cancer. Although data from twin studies suggest that MD has a strong genetic component, the exact genes involved remain to be identified. Alterations in stromal composition and the number of epithelial cells are the most predominant histopathological determinants of mammographic density. Interactions between the breast stroma and epithelium are critically important in the maturation and development of the mammary gland and the cross-talk between these cells are mediated by paracrine growth factors and cytokines. The potential impact of genetic variation in growth factors and cytokines on MD is largely unknown. Methods We investigated the association between 89 single nucleotide polymorphisms (SNPs) in 7 cytokine/growth-factor genes (FGFR2, IGFBP1, IGFBP3, TGFB1, TNF, VEGF, IL6) and percent MD in 301 premenopausal women (aged 50 to 55 years) participating in the Norwegian Breast Cancer Screening Program. We evaluated the suggestive associations in 216 premenopausal Singapore Chinese Women of the same age. Results We found statistically significant associations between 9 tagging SNPs in the IL6 gene and MD in Norwegian women; the effect ranged from 3–5% in MD per variant allele (p-values = 0.02 to 0.0002). One SNP in the IL6 (rs10242595) significantly influenced MD in Singapore Chinese women. Conclusion Genetic variations in IL6 may be associated with MD and therefore may be an indicator of breast cancer risk in premenopausal women. PMID:23762340

  18. Study of quality perception in medical images based on comparison of contrast enhancement techniques in mammographic images

    NASA Astrophysics Data System (ADS)

    Matheus, B.; Verçosa, L. B.; Barufaldi, B.; Schiabel, H.

    2014-03-01

    With the absolute prevalence of digital images in mammography several new tools became available for radiologist; such as CAD schemes, digital zoom and contrast alteration. This work focuses in contrast variation and how the radiologist reacts to these changes when asked to evaluated image quality. Three contrast enhancing techniques were used in this study: conventional equalization, CCB Correction [1] - a digitization correction - and value subtraction. A set of 100 images was used in tests from some available online mammographic databases. The tests consisted of the presentation of all four versions of an image (original plus the three contrast enhanced images) to the specialist, requested to rank each one from the best up to worst quality for diagnosis. Analysis of results has demonstrated that CCB Correction [1] produced better images in almost all cases. Equalization, which mathematically produces a better contrast, was considered the worst for mammography image quality enhancement in the majority of cases (69.7%). The value subtraction procedure produced images considered better than the original in 84% of cases. Tests indicate that, for the radiologist's perception, it seems more important to guaranty full visualization of nuances than a high contrast image. Another result observed is that the "ideal" scanner curve does not yield the best result for a mammographic image. The important contrast range is the middle of the histogram, where nodules and masses need to be seen and clearly distinguished.

  19. Qualitative Student Models.

    ERIC Educational Resources Information Center

    Clancey, William J.

    The concept of a qualitative model is used as the focus of this review of qualitative student models in order to compare alternative computational models and to contrast domain requirements. The report is divided into eight sections: (1) Origins and Goals (adaptive instruction, qualitative models of processes, components of an artificial…

  20. Understanding & Conducting Qualitative Research.

    ERIC Educational Resources Information Center

    Stainback, Susan; Stainback, William

    In this book, which applies the state of the art in qualitative research to special education, qualitative research is used as a generic term for investigative methodologies described variously as ethnographic, naturalistic, anthropological, field research, or participant-observer research. Chapter 1 introduces and defines qualitative research and…

  1. The Qualitative Dimension.

    ERIC Educational Resources Information Center

    Lodge-Peters, Dianne S.

    The qualitative dimension of educational research methodology is explored, and the literature of qualitative methodology is reviewed so researchers may (1) understand more fully the qualitative dimension as it, in turn, fits within the parameters of educational research as a whole, and (2) have more informed access to the sometimes daunting array…

  2. Effectively Communicating Qualitative Research

    ERIC Educational Resources Information Center

    Ponterotto, Joseph G.; Grieger, Ingrid

    2007-01-01

    This article is a guide for counseling researchers wishing to communicate the methods and results of their qualitative research to varied audiences. The authors posit that the first step in effectively communicating qualitative research is the development of strong qualitative research skills. To this end, the authors review a process model for…

  3. Mammographic Density Phenotypes and Risk of Breast Cancer: A Meta-analysis

    PubMed Central

    Graff, Rebecca E.; Ursin, Giske; dos Santos Silva, Isabel; McCormack, Valerie; Baglietto, Laura; Vachon, Celine; Bakker, Marije F.; Giles, Graham G.; Chia, Kee Seng; Czene, Kamila; Eriksson, Louise; Hall, Per; Hartman, Mikael; Warren, Ruth M. L.; Hislop, Greg; Chiarelli, Anna M.; Hopper, John L.; Krishnan, Kavitha; Li, Jingmei; Li, Qing; Pagano, Ian; Rosner, Bernard A.; Wong, Chia Siong; Scott, Christopher; Stone, Jennifer; Maskarinec, Gertraud; Boyd, Norman F.; van Gils, Carla H.

    2014-01-01

    Background Fibroglandular breast tissue appears dense on mammogram, whereas fat appears nondense. It is unclear whether absolute or percentage dense area more strongly predicts breast cancer risk and whether absolute nondense area is independently associated with risk. Methods We conducted a meta-analysis of 13 case–control studies providing results from logistic regressions for associations between one standard deviation (SD) increments in mammographic density phenotypes and breast cancer risk. We used random-effects models to calculate pooled odds ratios and 95% confidence intervals (CIs). All tests were two-sided with P less than .05 considered to be statistically significant. Results Among premenopausal women (n = 1776 case patients; n = 2834 control subjects), summary odds ratios were 1.37 (95% CI = 1.29 to 1.47) for absolute dense area, 0.78 (95% CI = 0.71 to 0.86) for absolute nondense area, and 1.52 (95% CI = 1.39 to 1.66) for percentage dense area when pooling estimates adjusted for age, body mass index, and parity. Corresponding odds ratios among postmenopausal women (n = 6643 case patients; n = 11187 control subjects) were 1.38 (95% CI = 1.31 to 1.44), 0.79 (95% CI = 0.73 to 0.85), and 1.53 (95% CI = 1.44 to 1.64). After additional adjustment for absolute dense area, associations between absolute nondense area and breast cancer became attenuated or null in several studies and summary odds ratios became 0.82 (95% CI = 0.71 to 0.94; P heterogeneity = .02) for premenopausal and 0.85 (95% CI = 0.75 to 0.96; P heterogeneity < .01) for postmenopausal women. Conclusions The results suggest that percentage dense area is a stronger breast cancer risk factor than absolute dense area. Absolute nondense area was inversely associated with breast cancer risk, but it is unclear whether the association is independent of absolute dense area. PMID:24816206

  4. MO-F-CAMPUS-I-01: Accuracy of Radiologists Interpretation of Mammographic Breast Density

    SciTech Connect

    Vedantham, S; Shi, L; Karellas, A; O’Connell, A

    2015-06-15

    Purpose: Several commercial and non-commercial software and techniques are available for determining breast density from mammograms. However, where mandated by law the breast density information communicated to the subject/patient is based on radiologist’s interpretation of breast density from mammograms. Several studies have reported on the concordance among radiologists in interpreting mammographic breast density. In this work, we investigated the accuracy of radiologist’s interpretation of breast density. Methods: Volumetric breast density (VBD) determined from 134 unilateral dedicated breast CT scans from 134 subjects was considered the truth. An MQSA-qualified study radiologist with more than 20 years of breast imaging experience reviewed the DICOM “for presentation” standard 2-view mammograms of the corresponding breasts and assigned BIRADS breast density categories. For statistical analysis, the breast density categories were dichotomized in two ways; fatty vs. dense breasts where “fatty” corresponds to BIRADS breast density categories A/B, and “dense” corresponds to BIRADS breast density categories C/D, and extremely dense vs. fatty to heterogeneously dense breasts, where extremely dense corresponds to BIRADS breast density category D and BIRADS breast density categories A through C were grouped as fatty to heterogeneously dense breasts. Logistic regression models (SAS 9.3) were used to determine the association between radiologist’s interpretation of breast density and VBD from breast CT, from which the area under the ROC (AUC) was determined. Results: Both logistic regression models were statistically significant (Likelihood Ratio test, p<0.0001). The accuracy (AUC) of the study radiologist for classification of fatty vs. dense breasts was 88.4% (95% CI: 83–94%) and for classification of extremely dense breast was 94.3% (95% CI: 90–98%). Conclusion: The accuracy of the radiologist in classifying dense and extremely dense breasts is

  5. Association between the Adherence to the International Guidelines for Cancer Prevention and Mammographic Density

    PubMed Central

    Castelló, Adela; Prieto, Leandro; Ederra, María; Salas-Trejo, Dolores; Vidal, Carmen; Sánchez-Contador, Carmen; Santamariña, Carmen; Pedraz, Carmen; Moreo, Pilar; Aragonés, Nuria; Pérez-Gómez, Beatriz; Lope, Virginia; Vioque, Jesús; Pollán, Marina

    2015-01-01

    Introduction Mammographic density (MD) is considered a strong predictor of Breast Cancer (BC). The objective of the present study is to explore the association between MD and the compliance with the World Cancer Research Fund and the American Institute for Cancer Research (WCRF/AICR) recommendations for cancer prevention. Methods Data of 3584 women attending screening from a population-based multicenter cross-sectional study (DDM-Spain) collected from October 7, 2007 through July 14, 2008, was used to calculate a score that measures the level of compliance with the WCRF/AICR recommendations: R1)Maintain adequate body weight; R2)Be physically active; 3R)Limit the intake of high density foods; R4)Eat mostly plant foods; R5)Limit the intake of animal foods; R6)Limit alcohol intake; R7)Limit salt and salt preserved food intake; R8)Meet nutritional needs through diet. The association between the score and MD (assessed by a single radiologist using a semi-quantitative scale) was evaluated using ordinal logistic models with random center-specific intercepts adjusted for the main determinants of MD. Stratified analyses by menopausal status and smoking status were also carried out. Results A higher compliance with the WCRF/AICR recommendations was associated with lower MD (OR1-unit increase = 0.93 95%CI:0.86;0.99). The association was stronger in postmenopausal women (OR = 0.91 95%CI:0.84;0.99) and nonsmokers (OR = 0.87;95%CI:0.80;0.96 for nonsmokers, OR = 1.01 95%CI:0.91;1.12 for smokers, P-interaction = 0.042). Among nonsmokers, maintaining adequate body weight (OR = 0.81 95%CI:0.65;1.01), practicing physical activity (OR = 0.68 95%CI:0.48;0.96) and moderating the intake of high-density foods (OR = 0.58 95%CI:0.40;0.86) and alcoholic beverages (OR = 0.76 95%CI:0.55;1.05) were the recommendations showing the strongest associations with MD. Conclusions postmenopausal women and non-smokers with greater compliance with the WCRF/AICR guidelines have lower MD. These results may

  6. Neighbourhood search feature selection method for content-based mammogram retrieval.

    PubMed

    Chandy, D Abraham; Christinal, A Hepzibah; Theodore, Alwyn John; Selvan, S Easter

    2017-03-01

    Content-based image retrieval plays an increasing role in the clinical process for supporting diagnosis. This paper proposes a neighbourhood search method to select the near-optimal feature subsets for the retrieval of mammograms from the Mammographic Image Analysis Society (MIAS) database. The features based on grey level cooccurrence matrix, Daubechies-4 wavelet, Gabor, Cohen-Daubechies-Feauveau 9/7 wavelet and Zernike moments are extracted from mammograms available in the MIAS database to form the combined or fused feature set for testing various feature selection methods. The performance of feature selection methods is evaluated using precision, storage requirement and retrieval time measures. Using the proposed method, a significant improvement is achieved in mean precision rate and feature dimension. The results show that the proposed method outperforms the state-of-the-art feature selection methods.

  7. The influence of mammogram acquisition on the mammographic density and breast cancer association in the mayo mammography health study cohort

    PubMed Central

    2012-01-01

    Introduction Mammographic density is a strong risk factor for breast cancer. Image acquisition technique varies across mammograms to limit radiation and produce a clinically useful image. We examined whether acquisition technique parameters at the time of mammography were associated with mammographic density and whether the acquisition parameters confounded the density and breast cancer association. Methods We examined this question within the Mayo Mammography Health Study (MMHS) cohort, comprised of 19,924 women (51.2% of eligible) seen in the Mayo Clinic mammography screening practice from 2003 to 2006. A case-cohort design, comprising 318 incident breast cancers diagnosed through December 2009 and a random subcohort of 2,259, was used to examine potential confounding of mammogram acquisition technique parameters (x-ray tube voltage peak (kVp), milliampere-seconds (mAs), thickness and compression force) on the density and breast cancer association. The Breast Imaging Reporting and Data System four-category tissue composition measure (BI-RADS) and percent density (PD) (Cumulus program) were estimated from screen-film mammograms at time of enrollment. Spearman correlation coefficients (r) and means (standard deviations) were used to examine the relationship of density measures with acquisition parameters. Hazard ratios (HR) and C-statistics were estimated using Cox proportional hazards regression, adjusting for age, menopausal status, body mass index and postmenopausal hormones. A change in the HR of at least 15% indicated confounding. Results Adjusted PD and BI-RADS density were associated with breast cancer (p-trends < 0.001), with a 3 to 4-fold increased risk in the extremely dense vs. fatty BI-RADS categories (HR: 3.0, 95% CI, 1.7 - 5.1) and the ≥ 25% vs. ≤ 5% PD categories (HR: 3.8, 95% CI, 2.5 - 5.9). Of the acquisition parameters, kVp was not correlated with PD (r = 0.04, p = 0.07). Although thickness (r = -0.27, p < 0.001), compression force (r = -0

  8. Being a qualitative researcher.

    PubMed

    Holloway, Immy; Biley, Francis C

    2011-07-01

    This article, from a keynote address, is the result of some of the things which I learned about qualitative research during my many years of doing and teaching it. The main point I make is that qualitative researchers should present a good story which is based on evidence but focused on meaning rather than measurement. In qualitative inquiry, the researchers' selves are involved, their experiences become a resource. Researchers cannot distance themselves from the other participants, although they cannot fully present their meaning and experience. I also discuss voice, paradigm, and innovation as potentially problematic issues in qualitative research. These are terms often used but not always examined for their meaning in qualitative inquiry. If researchers are aware and sensitive, rather than overemotional or self-absorbed, qualitative research can be enlightening, person-centered, and humanistic.

  9. The qualitative research proposal.

    PubMed

    Klopper, H

    2008-12-01

    Qualitative research in the health sciences has had to overcome many prejudices and a number of misunderstandings, but today qualitative research is as acceptable as quantitative research designs and is widely funded and published. Writing the proposal of a qualitative study, however, can be a challenging feat, due to the emergent nature of the qualitative research design and the description of the methodology as a process. Even today, many sub-standard proposals at post-graduate evaluation committees and application proposals to be considered for funding are still seen. This problem has led the researcher to develop a framework to guide the qualitative researcher in writing the proposal of a qualitative study based on the following research questions: (i) What is the process of writing a qualitative research proposal? and (ii) What does the structure and layout of a qualitative proposal look like? The purpose of this article is to discuss the process of writing the qualitative research proposal, as well as describe the structure and layout of a qualitative research proposal. The process of writing a qualitative research proposal is discussed with regards to the most important questions that need to be answered in your research proposal with consideration of the guidelines of being practical, being persuasive, making broader links, aiming for crystal clarity and planning before you write. While the structure of the qualitative research proposal is discussed with regards to the key sections of the proposal, namely the cover page, abstract, introduction, review of the literature, research problem and research questions, research purpose and objectives, research paradigm, research design, research method, ethical considerations, dissemination plan, budget and appendices.

  10. Critiquing qualitative research.

    PubMed

    Beck, Cheryl Tatano

    2009-10-01

    The ability to critique research is a valuable skill that is fundamental to a perioperative nurse's ability to base his or her clinical practice on evidence derived from research. Criteria differ for critiquing a quantitative versus a qualitative study (ie, statistics are evaluated in a quantitative study, but not in a qualitative study). This article provides on guidelines for assessing qualitative research. Excerpts from a published qualitative research report are summarized and then critiqued. Questions are provided that help evaluate different sections of a research study (eg, sample, data collection methods, data analysis).

  11. Overview of qualitative research.

    PubMed

    Grossoehme, Daniel H

    2014-01-01

    Qualitative research methods are a robust tool for chaplaincy research questions. Similar to much of chaplaincy clinical care, qualitative research generally works with written texts, often transcriptions of individual interviews or focus group conversations and seeks to understand the meaning of experience in a study sample. This article describes three common methodologies: ethnography, grounded theory, and phenomenology. Issues to consider relating to the study sample, design, and analysis are discussed. Enhancing the validity of the data, as well reliability and ethical issues in qualitative research are described. Qualitative research is an accessible way for chaplains to contribute new knowledge about the sacred dimension of people's lived experience.

  12. Analysis of confidence level scores from an ROC study: comparison of three mammographic systems for detection of simulated calcifications

    NASA Astrophysics Data System (ADS)

    Lai, Chao-Jen; Shaw, Chris C.; Whitman, Gary J.; Yang, Wei T.; Dempsey, Peter J.

    2005-04-01

    The purpose of this study is to compare the detection performance of three different mammography systems: screen/film (SF) combination, a-Si/CsI flat-panel (FP-), and charge-coupled device (CCD-) based systems. A 5-cm thick 50% adipose/50% glandular breast tissue equivalent slab phantom was used to provide an uniform background. Calcium carbonate grains of three different size groups were used to simulate microcalcifications (MCs): 112-125, 125-140, and 140-150 μm overlapping with the uniform background. Calcification images were acquired with the three mammography systems. Digital images were printed on hardcopy films. All film images were displayed on a mammographic viewer and reviewed by 5 mammographers. The visibility of the MC was rated with a 5-point confidence rating scale for each detection task, including the negative controls. Scores were averaged over all readers for various detectors and size groups. Receiver operating characteristic (ROC) analysis was performed and the areas under the ROC curves (Az"s) were computed for various imaging conditions. The results shows that (1) the FP-based system performed significantly better than the SF and CCD-based systems for individual size groups using ROC analysis (2) the FP-based system also performed significantly better than the SF and CCD-based systems for individual size groups using averaged confidence scale, and (3) the results obtained from the Az"s were largely correlated with these from confidence level scores. However, the correlation varied slightly among different imaging conditions.

  13. Towards a nanoscale mammographic contrast agent: development of a modular pre-clinical dual optical/x-ray agent

    NASA Astrophysics Data System (ADS)

    Hill, Melissa L.; Gorelikov, Ivan; Niroui, Farnaz; Levitin, Ronald B.; Mainprize, James G.; Yaffe, Martin J.; Rowlands, J. A.; Matsuura, Naomi

    2013-08-01

    Contrast-enhanced digital mammography (CEDM) can provide improved breast cancer detection and characterization compared to conventional mammography by imaging the effects of tumour angiogenesis. Current small-molecule contrast agents used for CEDM are limited by a short plasma half-life and rapid extravasation into tissue interstitial space. To address these limitations, nanoscale agents that can remain intravascular except at sites of tumour angiogenesis can be used. For CEDM, this agent must be both biocompatible and strongly attenuate mammographic energy x-rays. Nanoscale perfluorooctylbromide (PFOB) droplets have good x-ray attenuation and have been used in patients for other applications. However, the macroscopic scale of x-ray imaging (50-100 µm) is inadequate for direct verification that PFOB droplets localize at sites of breast tumour angiogenesis. For efficient pre-clinical optimization for CEDM, we integrated an optical marker into PFOB droplets for microscopic assessment (≪50 µm). To develop PFOB droplets as a new nanoscale mammographic contrast agent, PFOB droplets were labelled with fluorescent quantum dots (QDs). The droplets had mean diameters of 160 nm, fluoresced at 635 nm and attenuated x-ray spectra at 30.5 keV mean energy with a relative attenuation of 5.6 ± 0.3 Hounsfield units (HU) mg-1 mL-1 QD-PFOB. With the agent loaded into tissue phantoms, good correlation between x-ray attenuation and optical fluorescence was found (R2 = 0.96), confirming co-localization of the QDs with PFOB for quantitative assessment using x-ray or optical methods. Furthermore, the QDs can be removed from the PFOB agent without affecting its x-ray attenuation or structural properties for expedited translation of optimized PFOB droplet formulations into patients.

  14. Polymorphisms in genes involved in estrogen and progesterone metabolism and mammographic density changes in women randomized to postmenopausal hormone therapy: results from a pilot study

    PubMed Central

    Lord, Sarah J; Mack, Wendy J; Van Den Berg, David; Pike, Malcolm C; Ingles, Sue A; Haiman, Christopher A; Wang, Wei; Parisky, Yuri R; Hodis, Howard N; Ursin, Giske

    2005-01-01

    Introduction Mammographic density is a strong independent risk factor for breast cancer, and can be modified by hormonal exposures. Identifying genetic variants that determine increases in mammographic density in hormone users may be important in understanding hormonal carcinogenesis of the breast. Methods We obtained mammograms and DNA from 232 postmenopausal women aged 45 to 75 years who had participated in one of two randomized, double-blind clinical trials with estrogen therapy (104 women, taking 1 mg/day of micronized 17β-estradiol, E2), combined estrogen and progestin therapy (34 women, taking 17β-estradiol and 5 mg/day of medroxyprogesterone acetate for 12 days/month) or matching placebos (94 women). Mammographic percentage density (MPD) was measured on baseline and 12-month mammograms with a validated computer-assisted method. We evaluated polymorphisms in genes involved in estrogen metabolism (catechol-O-methyltransferase (COMT (Val158Met)), cytochrome P450 1B1 (CYP1B1 (Val432Leu)), UDP-glucuronosyltransferase 1A1 (UGT1A1 (<7/≥ 7 TA repeats))) and progesterone metabolism (aldo-keto reductase 1C4 (AKR1C4 (Leu311Val))) with changes in MPD. Results The adjusted mean change in MPD was +4.6% in the estrogen therapy arm and +7.2% in the combined estrogen and progestin therapy arm, compared with +0.02% in the placebo arm (P = 0.0001). None of the genetic variants predicted mammographic density changes in women using estrogen therapy. Both the AKR1C4 and the CYP1B1 polymorphisms predicted mammographic density change in the combined estrogen and progestin therapy group (P < 0.05). In particular, the eight women carrying one or two low-activity AKR1C4 Val alleles showed a significantly greater increase in MPD (16.7% and 29.3%) than women homozygous for the Leu allele (4.0%). Conclusion Although based on small numbers, these findings suggest that the magnitude of the increase in mammographic density in women using combined estrogen and progestin therapy may be

  15. Image simulation and a model of noise power spectra across a range of mammographic beam qualities

    SciTech Connect

    Mackenzie, Alistair Dance, David R.; Young, Kenneth C.; Diaz, Oliver

    2014-12-15

    Purpose: The aim of this work is to create a model to predict the noise power spectra (NPS) for a range of mammographic radiographic factors. The noise model was necessary to degrade images acquired on one system to match the image quality of different systems for a range of beam qualities. Methods: Five detectors and x-ray systems [Hologic Selenia (ASEh), Carestream computed radiography CR900 (CRc), GE Essential (CSI), Carestream NIP (NIPc), and Siemens Inspiration (ASEs)] were characterized for this study. The signal transfer property was measured as the pixel value against absorbed energy per unit area (E) at a reference beam quality of 28 kV, Mo/Mo or 29 kV, W/Rh with 45 mm polymethyl methacrylate (PMMA) at the tube head. The contributions of the three noise sources (electronic, quantum, and structure) to the NPS were calculated by fitting a quadratic at each spatial frequency of the NPS against E. A quantum noise correction factor which was dependent on beam quality was quantified using a set of images acquired over a range of radiographic factors with different thicknesses of PMMA. The noise model was tested for images acquired at 26 kV, Mo/Mo with 20 mm PMMA and 34 kV, Mo/Rh with 70 mm PMMA for three detectors (ASEh, CRc, and CSI) over a range of exposures. The NPS were modeled with and without the noise correction factor and compared with the measured NPS. A previous method for adapting an image to appear as if acquired on a different system was modified to allow the reference beam quality to be different from the beam quality of the image. The method was validated by adapting the ASEh flat field images with two thicknesses of PMMA (20 and 70 mm) to appear with the imaging characteristics of the CSI and CRc systems. Results: The quantum noise correction factor rises with higher beam qualities, except for CR systems at high spatial frequencies, where a flat response was found against mean photon energy. This is due to the dominance of secondary quantum noise

  16. Evaluation Of Digital Unsharp-Mask Filtering For The Detection Of Subtle Mammographic Microcalcifications

    NASA Astrophysics Data System (ADS)

    Chan, Heang-Ping; Vyborny, Carl J.; MacMahon, Heber; Metz, Charles E.; Doi, Kunio; Sickles, Edward A.

    1986-06-01

    We have conducted a study to assess the effects of digitization and unsharp-mask filtering on the ability of observers to detect subtle microcalcifications in mammograms. Thirty-two conventional screen-film mammograms were selected from patient files by two experienced mammographers. Twelve of the mammograms contained a suspicious cluster of microcalcifications in patients who subsequently underwent biopsy. Twenty of the mammograms were normal cases which were initially interpreted as being free of clustered microcalcifications and did not demonstrate such on careful review. The mammograms were digitized with a high-quality Fuji image processing/simulation system. The system consists of two drum scanners with which an original radiograph can be digitized, processed by a minicomputer, and reconstituted on film. In this study, we employed a sampling aperture of 0.1 mm X 0.1 mm and a sampling distance of 0.1 mm. The density range from 0.2 to 2.75 was digitized to 1024 grey levels per pixel. The digitized images were printed on a single emulsion film with a display aperture having the same size as the sampling aperture. The system was carefully calibrated so that the density and contrast of a digitized image were closely matched to those of the original radiograph. Initially, we evaluated the effects of the weighting factor and the mask size of a unsharp-mask filter on the appearance of mammograms for various types of breasts. Subjective visual comparisons suggested that a mask size of 91 X 91 pixels (9.1 mm X 9.1 mm) enhances the visibility of microcalcifications without excessively increasing the high-frequency noise. Further, a density-dependent weighting factor that increases linearly from 1.5 to 3.0 in the density range of 0.2 to 2.5 enhances the contrast of microcalcifications without introducing many potentially confusing artifacts in the low-density areas. An unsharp-mask filter with these parameters was used to process the digitized mammograms. We conducted

  17. A Clinicopathologic Correlation of Mammographic Parenchymal Patterns and Associated Risk Factors for Human Mammary Carcinoma

    PubMed Central

    Bland, Kirby I.; Kuhns, James G.; Buchanan, Jerry B.; Dwyer, Patricia A.; Heuser, Louis F.; O'Connor, Carol A.; Gray, Laman A.; Polk, Hiram C.

    1982-01-01

    The five-year screening experience for 10,131 asymptomatic women evaluated at the Louisville Breast Cancer Detection Demonstration Project (LBCDDP) disclosed 144 breast carcinomas in 1,209 patients (12%) aged 35 to 74 years in whom 904 biopsies and 305 aspirations were performed. This study included 44,711 high-quality xeromammograms (XM) prospectively classified by the modified Wolfe mammographic parenchymal patterns into low-risk (N1, P1) versus high-risk (P2, DY) groups, with expansion of the P2 cohort into three additional categories. Using BMDP computer-program analysis, each XM pattern was collated with 21 nonneoplastic and 18 malignant pathologic variables and commonly associated risk factors. A separate analysis of epithelial proliferative and nonproliferative fibrocystic disease of the breast (FCDB) was performed. The histopathology for each biopsy, with distinction of FCDB and neoplasms, was analyzed with regard to the statistical probability of influencing the XM pattern. An average of 1.05 biopsies per patient were performed in women with findings suggestive of carcinoma at clinical and/or XM examinations. An equal distribution of the N1, P1, and P2 DYXM patterns was observed in the 10,131 screenees. Of 8.5% of the screened population having biopsies, 623 were observed to have nonproliferative FCDB and 137, proliferative FCDB. For women 50 years of age or younger, these pathologic variables were seen more frequently in the P2 DY patterns (p < 0.001), whereas no difference in XM pattern distribution was observed for the screenee 50 years of age or older for proliferative FCDB (p = 0.65). Sixteen percent of the biopsied/aspirated lesions were carcinomas, yielding a biopsy/cancer ratio of 6.25:1. These in situ and invasive neoplasms were more commonly (p < 0.04) observed in 55% of the P2 (P2f, P2n, P2c) categories, while 64% of all cancers appeared more frequently in the P2 DY subgroup (p <0.001), compared with this pattern in the screened population. An

  18. Visualizing Qualitative Information

    ERIC Educational Resources Information Center

    Slone, Debra J.

    2009-01-01

    The abundance of qualitative data in today's society and the need to easily scrutinize, digest, and share this information calls for effective visualization and analysis tools. Yet, no existing qualitative tools have the analytic power, visual effectiveness, and universality of familiar quantitative instruments like bar charts, scatter-plots, and…

  19. Teaching Qualitative Research

    ERIC Educational Resources Information Center

    Delyser, Dydia

    2008-01-01

    Explicitly qualitative research has never before been so popular in human geography, and this article hopes to encourage more graduate students and faculty members to undertake the teaching of qualitative geography. The article describes one such course for graduate students, highlighting its challenges and rewards, and focusing on exercises…

  20. Qualitative Studies: Historiographical Antecedents.

    ERIC Educational Resources Information Center

    Mills, Rilla Dean

    This paper provides an overview of qualitative studies' antecedents among historiographers and of the positivist tide which nearly engulfed them. Humans live by interpretations. The task of social science--the basic task of qualitative studies--is to study these interpretations so that we can better understand the meanings which people use to…

  1. Part two: Qualitative research.

    PubMed

    Quick, J; Hall, S

    2015-01-01

    This second article in the series Spotlight on Research focuses on qualitative research, its applications, principles and methodologies. It provides an insight into how this approach can be used within the perioperative setting and gives advice for practitioners looking to undertake a qualitative research study.

  2. Texture feature extraction methods for microcalcification classification in mammograms

    NASA Astrophysics Data System (ADS)

    Soltanian-Zadeh, Hamid; Pourabdollah-Nezhad, Siamak; Rafiee Rad, Farshid

    2000-06-01

    We present development, application, and performance evaluation of three different texture feature extraction methods for classification of benign and malignant microcalcifications in mammograms. The steps of the work accomplished are as follows. (1) A total of 103 regions containing microcalcifications were selected from a mammographic database. (2) For each region, texture features were extracted using three approaches: co-occurrence based method of Haralick; wavelet transformations; and multi-wavelet transformations. (3) For each set of texture features, most discriminating features and their optimal weights were found using a real-valued genetic algorithm (GA) and a training set. For each set of features and weights, a KNN classifier and a malignancy criterion were used to generate the corresponding ROC curve. The malignancy of a given sample was defined as the number of malignant neighbors among its K nearest neighbors. The GA found a population with the largest area under the ROC curve. (4) The best results obtained using each set of features were compared. The best set of features generated areas under the ROC curve ranging from 0.82 to 0.91. The multi-wavelet method outperformed the other two methods, and the wavelet features were superior to the Haralick features. Among the multi-wavelet methods, redundant initialization generated superior results compared to non-redundant initialization. For the best method, a true positive fraction larger than 0.85 and a false positive fraction smaller than 0.1 were obtained.

  3. Qualitative research in thanatology.

    PubMed

    Carverhill, Philip A

    2002-04-01

    A new research paradigm has been emerging which holds significant potential for the field of death studies. The qualitative project is a diverse collection of methodologies that focuses its interests on the words, narratives, and stories of individuals and groups. Part of its appeal may lie in the inherent closeness of fit between qualitative inquiry and applied work with the dying and the bereaved. The author introduces the individual articles in this special issue and outlines the development of the project as well as some current issues in qualitative research in thanatology.

  4. Handbook of Qualitative Research. Second Edition.

    ERIC Educational Resources Information Center

    Denzin, Norman K., Ed.; Lincoln, Yvonna S., Ed.

    This handbook's second edition represents the state of the art for the theory and practice of qualitative inquiry. It features eight new topics, including autoethnography, critical race theory, applied ethnography, queer theory, and "testimonio"every chapter in the handbook has been thoroughly revised and updated. The book…

  5. Using Qualitative Methods to Study Friendships

    ERIC Educational Resources Information Center

    Bukowski, William; Lisboa, Carolina

    2005-01-01

    Basic concepts and procedures of qualitative analysis are discussed, especially as they relate to the study of the features, processes, and effects of friendships. The contributions of the previous chapters are presented according to theory and research on friendship as a developmental process.

  6. Reliability of Breast Ultrasound BI-RADS Final Assessment in Mammographically Negative Patients with Nipple Discharge and Radiologic Predictors of Malignancy

    PubMed Central

    Park, Chae Jung; Kim, Eun-Kyung; Moon, Hee Jung; Yoon, Jung Hyun

    2016-01-01

    Purpose The purpose of this study was to retrospectively investigate the reliability of breast ultrasound (US) Breast Imaging Reporting and Data System (BI-RADS) final assessment in mammographically negative patients with pathologic nipple discharge, and to determine the clinical and ultrasonographic variables associated with malignancy in this group of patients. Methods A total of 65 patients with 67 mammographically negative breast lesions that were pathologically confirmed through US-guided biopsy were included. Results Of the 53 BI-RADS category 4 and 5 lesions, eight (15.1%) were malignant (six ductal carcinomas in situ, one invasive ductal carcinoma, and one solid papillary carcinoma). There was no malignancy among the remaining 14 category 3 lesions. Malignant lesions more frequently displayed a round or irregular shape (75.0%, 6/8; p=0.030) and nonparallel orientation (33.3%, 4/12; p=0.029) compared to the benign lesions. The increase in the BI-RADS category corresponded with a rise in the malignancy rate (p=0.004). Conclusion The BI-RADS lexicon and final assessment of breast US reliably detect and characterize malignancy in mammographically negative patients with pathologic nipple discharge. PMID:27721881

  7. Qualitative Case Study Guidelines

    DTIC Science & Technology

    2013-11-01

    methods in public relations and marketing communications. New York, Routledge 166-185 13. Denzin , N. K. (1978) The Research Act: A Theoretical...Introduction to Sociological Methods. 2nd ed. New York, McGraw-Hill 14. Denzin , N. K. and Lincoln, Y. S. (2011) The SAGE Handbook of Qualitative...The Art of Science. In: Denzin , N. K. and Lincoln, Y. S. (eds.) Handbook of Qualitative Research. Thousand Oaks, Sage 19. GAO (1990) Case Study

  8. Individualised Qualitative Evaluation.

    ERIC Educational Resources Information Center

    O'Sullivan, Denis

    1987-01-01

    The author discusses student evaluation in relation to adult and continuing education programs offered by the Department of Adult Education, University College, Cork. He highlights the need for a more individualized and interactive approach to evaluation, allowing the student to benefit from qualitative feedback in the process of being evaluated.…

  9. First Semester Qualitative Analysis

    ERIC Educational Resources Information Center

    DeLap, James H.

    1969-01-01

    Describes a two-hour laboratory course entitled "Chemical Periodicity offered first semester of the freshman year. Three cation groups, one anion group, and a final unkown salt are qualitatively analyzed. Course fosters scientific thinking in experimentation by encouraging student-initiated schemes of analyses rather than "cookbook schemes. (RR)

  10. The Qualitative Similarity Hypothesis

    ERIC Educational Resources Information Center

    Paul, Peter V.; Lee, Chongmin

    2010-01-01

    Evidence is presented for the qualitative similarity hypothesis (QSH) with respect to children and adolescents who are d/Deaf or hard of hearing. The primary focus is on the development of English language and literacy skills, and some information is provided on the acquisition of English as a second language. The QSH is briefly discussed within…

  11. Advances in Qualitative Research.

    ERIC Educational Resources Information Center

    1998

    This document contains five papers from a symposium on advances in qualitative research in human resource development (HRD). "Case Study and Its Virtuoso Possibilities" (Verna J. Willis) asserts that the case study method is particularly well suited for research in HRD because its creative and investigative possibilities have not yet…

  12. Disciplining Qualitative Research

    ERIC Educational Resources Information Center

    Denzin, Norman K.; Lincoln, Yvonna S.; Giardina, Michael D.

    2006-01-01

    Qualitative research exists in a time of global uncertainty. Around the world, governments are attempting to regulate scientific inquiry by defining what counts as "good" science. These regulatory activities raise fundamental, philosophical epistemological, political and pedagogical issues for scholarship and freedom of speech in the…

  13. Entropy Is Simple, Qualitatively.

    ERIC Educational Resources Information Center

    Lambert, Frank L.

    2002-01-01

    Suggests that qualitatively, entropy is simple. Entropy increase from a macro viewpoint is a measure of the dispersal of energy from localized to spread out at a temperature T. Fundamentally based on statistical and quantum mechanics, this approach is superior to the non-fundamental "disorder" as a descriptor of entropy change. (MM)

  14. Large scale deep learning for computer aided detection of mammographic lesions.

    PubMed

    Kooi, Thijs; Litjens, Geert; van Ginneken, Bram; Gubern-Mérida, Albert; Sánchez, Clara I; Mann, Ritse; den Heeten, Ard; Karssemeijer, Nico

    2017-01-01

    Recent advances in machine learning yielded new techniques to train deep neural networks, which resulted in highly successful applications in many pattern recognition tasks such as object detection and speech recognition. In this paper we provide a head-to-head comparison between a state-of-the art in mammography CAD system, relying on a manually designed feature set and a Convolutional Neural Network (CNN), aiming for a system that can ultimately read mammograms independently. Both systems are trained on a large data set of around 45,000 images and results show the CNN outperforms the traditional CAD system at low sensitivity and performs comparable at high sensitivity. We subsequently investigate to what extent features such as location and patient information and commonly used manual features can still complement the network and see improvements at high specificity over the CNN especially with location and context features, which contain information not available to the CNN. Additionally, a reader study was performed, where the network was compared to certified screening radiologists on a patch level and we found no significant difference between the network and the readers.

  15. Gravitational wave background from Standard Model physics: qualitative features

    SciTech Connect

    Ghiglieri, J.; Laine, M. E-mail: laine@itp.unibe.ch

    2015-07-01

    Because of physical processes ranging from microscopic particle collisions to macroscopic hydrodynamic fluctuations, any plasma in thermal equilibrium emits gravitational waves. For the largest wavelengths the emission rate is proportional to the shear viscosity of the plasma. In the Standard Model at 0T > 16 GeV, the shear viscosity is dominated by the most weakly interacting particles, right-handed leptons, and is relatively large. We estimate the order of magnitude of the corresponding spectrum of gravitational waves. Even though at small frequencies (corresponding to the sub-Hz range relevant for planned observatories such as eLISA) this background is tiny compared with that from non-equilibrium sources, the total energy carried by the high-frequency part of the spectrum is non-negligible if the production continues for a long time. We suggest that this may constrain (weakly) the highest temperature of the radiation epoch. Observing the high-frequency part directly sets a very ambitious goal for future generations of GHz-range detectors.

  16. Gravitational wave background from Standard Model physics: qualitative features

    SciTech Connect

    Ghiglieri, J.; Laine, M.

    2015-07-16

    Because of physical processes ranging from microscopic particle collisions to macroscopic hydrodynamic fluctuations, any plasma in thermal equilibrium emits gravitational waves. For the largest wavelengths the emission rate is proportional to the shear viscosity of the plasma. In the Standard Model at T>160 GeV, the shear viscosity is dominated by the most weakly interacting particles, right-handed leptons, and is relatively large. We estimate the order of magnitude of the corresponding spectrum of gravitational waves. Even though at small frequencies (corresponding to the sub-Hz range relevant for planned observatories such as eLISA) this background is tiny compared with that from non-equilibrium sources, the total energy carried by the high-frequency part of the spectrum is non-negligible if the production continues for a long time. We suggest that this may constrain (weakly) the highest temperature of the radiation epoch. Observing the high-frequency part directly sets a very ambitious goal for future generations of GHz-range detectors.

  17. Development and validation of a fully automated system for detection and diagnosis of mammographic lesions.

    PubMed

    Casti, Paola; Mencattini, Arianna; Salmeri, Marcello; Ancona, Antonietta; Mangieri, Fabio; Rangayyan, Rangaraj M

    2014-01-01

    We present a comprehensive and fully automated system for computer-aided detection and diagnosis of masses in mammograms. Novel methods for detection include: selection of suspicious focal areas based on analysis of the gradient vector field, rejection of oriented components of breast tissue using multidirectional Gabor filtering, and use of differential features for rejection of false positives (FPs) via clustering of the surrounding fibroglandular tissue. The diagnosis step is based on extraction of contour-independent features for characterization of lesions as benign or malignant from automatically detected circular and annular regions. A new unified 3D free-response receiver operating characteristic framework is introduced for global analysis of two binary categorization problems in cascade. In total, 3,080 suspicious focal areas were extracted from a set of 156 full-field digital mammograms, including 26 malignant tumors, 120 benign lesions, and 18 normal mammograms. The proposed system detected and diagnosed malignant tumors with a sensitivity of 0.96, 0.92, and 0.88 at, respectively, 1.83, 0.46, and 0.45 FPs/image, with two stages of stepwise logistic regression for selection of features, a cascade of Fisher linear discriminant analysis and an artificial neural network with radial basis functions, and leave-one-patient-out cross-validation.

  18. Mammographically screen-detected asymmetric densities with architectural distortion and normal ultrasound at assessment: Value of MRI as a problem-solving tool.

    PubMed

    Price, Jeremy; Chen, Suet Wan

    2015-06-01

    Four cases are presented in which asymptomatic clients from an Australian mammography screening programme (BreastScreen ACT) were recalled for assessment of an asymmetric density with possible architectural distortion. In all four women, mammographic work-up was equivocal and ultrasound showed no suspicious correlate for biopsy. It was then doubtful as to whether any significant lesion was present. In all four cases, MRI revealed the presence of malignancy. Breast MRI can be a useful problem-solving tool in the work-up of such cases.

  19. Intensity variation study of the radiation field in a mammographic system using thermoluminescent dosimeters TLD-900 (CaSO4:Dy)

    NASA Astrophysics Data System (ADS)

    Corrêa, E. L.; Silva, J. O.; Vivolo, V.; Potiens, M. P. A.; Daros, K. A. C.; Medeiros, R. B.

    2014-02-01

    This study presents the results of the intensity variation of the radiation field in a mammographic system using the thermoluminescent dosimeter TLD-900 (CaSO4:Dy). These TLDs were calibrated and characterized in an industrial X-ray system used for instruments calibration, in the energy range used in mammography. They were distributed in a matrix of 19 lines and five columns, covering an area of 18 cm×8 cm in the center of the radiation field on the clinical equipment. The results showed a variation of the intensity probably explained by the non-uniformity of the field due to the heel effect.

  20. Qualitative science policy.

    PubMed

    Mitcham, Carl

    2007-12-01

    Qualitative research struggles against a tide of quantitative methods. To assist in this struggle, it is useful to consider the historical and philosophical origins of quantitative methods as well as criticisms that have been raised against them. Although these criticisms have often been restricted to discussions in the philosophy of science, they have become increasingly prominent in debates regarding science policy. This article thus reviews current science policy debates concerning scientific autonomy and the linear model of science-society relationships. Then, having considered the multiple meanings of quality, it argues for a science policy reassessment of quantitative research, for deeper engagements between science policy and the social sciences, and finally, for a more explicit alliance between science policy and qualitative methods.

  1. Interviews in qualitative research.

    PubMed

    Peters, Kath; Halcomb, Elizabeth

    2015-03-01

    Interviews are a common method of data collection in nursing research. They are frequently used alone in a qualitative study or combined with other data collection methods in mixed or multi-method research. Semi-structured interviews, where the researcher has some predefined questions or topics but then probes further as the participant responds, can produce powerful data that provide insights into the participants' experiences, perceptions or opinions.

  2. Volume and tissue composition preserving deformation of breast CT images to simulate breast compression in mammographic imaging

    NASA Astrophysics Data System (ADS)

    Han, Tao; Chen, Lingyun; Lai, Chao-Jen; Liu, Xinming; Shen, Youtao; Zhong, Yuncheng; Ge, Shuaiping; Yi, Ying; Wang, Tianpeng; Shaw, Chris C.

    2009-02-01

    Images of mastectomy breast specimens have been acquired with a bench top experimental Cone beam CT (CBCT) system. The resulting images have been segmented to model an uncompressed breast for simulation of various CBCT techniques. To further simulate conventional or tomosynthesis mammographic imaging for comparison with the CBCT technique, a deformation technique was developed to convert the CT data for an uncompressed breast to a compressed breast without altering the breast volume or regional breast density. With this technique, 3D breast deformation is separated into two 2D deformations in coronal and axial views. To preserve the total breast volume and regional tissue composition, each 2D deformation step was achieved by altering the square pixels into rectangular ones with the pixel areas unchanged and resampling with the original square pixels using bilinear interpolation. The compression was modeled by first stretching the breast in the superior-inferior direction in the coronal view. The image data were first deformed by distorting the voxels with a uniform distortion ratio. These deformed data were then deformed again using distortion ratios varying with the breast thickness and re-sampled. The deformation procedures were applied in the axial view to stretch the breast in the chest wall to nipple direction while shrinking it in the mediolateral to lateral direction re-sampled and converted into data for uniform cubic voxels. Threshold segmentation was applied to the final deformed image data to obtain the 3D compressed breast model. Our results show that the original segmented CBCT image data were successfully converted into those for a compressed breast with the same volume and regional density preserved. Using this compressed breast model, conventional and tomosynthesis mammograms were simulated for comparison with CBCT.

  3. A method to determine the mammographic regions that show early changes due to the development of breast cancer

    NASA Astrophysics Data System (ADS)

    Karemore, Gopal; Nielsen, Mads; Karssemeijer, Nico; Brandt, Sami S.

    2014-11-01

    It is well understood nowadays that changes in the mammographic parenchymal pattern are an indicator of a risk of breast cancer and we have developed a statistical method that estimates the mammogram regions where the parenchymal changes, due to breast cancer, occur. This region of interest is computed from a score map by utilising the anatomical breast coordinate system developed in our previous work. The method also makes an automatic scale selection to avoid overfitting while the region estimates are computed by a nested cross-validation scheme. In this way, it is possible to recover those mammogram regions that show a significant difference in classification scores between the cancer and the control group. Our experiments suggested that the most significant mammogram region is the region behind the nipple and that can be justified by previous findings from other research groups. This result was conducted on the basis of the cross-validation experiments on independent training, validation and testing sets from the case-control study of 490 women, of which 245 women were diagnosed with breast cancer within a period of 2-4 years after the baseline mammograms. We additionally generalised the estimated region to another, mini-MIAS study and showed that the transferred region estimate gives at least a similar classification result when compared to the case where the whole breast region is used. In all, by following our method, one most likely improves both preclinical and follow-up breast cancer screening, but a larger study population will be required to test this hypothesis.

  4. Genetic variation in peroxisome proliferator-activated receptor gamma, soy, and mammographic density in Singapore Chinese women

    PubMed Central

    Lee, Eunjung; Hsu, Chris; Van den Berg, David; Ursin, Giske; Koh, Woon-Puay; Yuan, Jian-Min; Stram, Daniel O.; Yu, Mimi C.; Wu, Anna H.

    2012-01-01

    Background Peroxisome proliferator-activated receptor gamma (PPARγ) is a transcription factor important for adipogenesis and adipocyte differentiation. Data from animal studies suggest that PPARγ may be involved in breast tumorigenesis, but results from epidemiologic studies on the association between PPARγ variation and breast cancer risk have been mixed. Recent data suggest that soy isoflavones can activate PPARγ. We investigated the inter-relations of soy, PPARγ, and mammographic density (MD), a biomarker of breast cancer risk in a cross-sectional study of 2,038 women who were members of the population-based Singapore Chinese Health Study Cohort. Methods We assessed MD using a computer-assisted method. We used linear regression to examine the association between 26 tagging SNPs of PPARγ and their interaction with soy intake and MD. To correct for multiple testing, we calculated P-values adjusted for multiple correlated tests (PACT). Results Out of the 26 tested SNPs in the PPARγ, 6 SNPs were individually shown to be statistically significantly associated with MD (PACT=0.004∼0.049). A stepwise regression procedure identified that only rs880663 was independently associated with MD which decreased by 1.89% per minor allele (PACT=0.008).This association was significantly stronger in high soy consumers as MD decreased by 3.97% per minor allele of rs880663 in high soy consumers (PACT=0.006; P for interaction with lower soy intake=0.017). Conclusions Our data support that PPARγ genetic variation may be important in determining MD, particularly in high soy consumers. Impact Our findings may help to identify molecular targets and lifestyle intervention for future prevention research. PMID:22301832

  5. Comparison of Mammographic Density Assessed as Volumes and Areas among Women Undergoing Diagnostic Image-Guided Breast Biopsy

    PubMed Central

    Gierach, Gretchen L.; Geller, Berta M.; Shepherd, John A.; Patel, Deesha A.; Vacek, Pamela M.; Weaver, Donald L.; Chicoine, Rachael E.; Pfeiffer, Ruth M.; Fan, Bo; Mahmoudzadeh, Amir Pasha; Wang, Jeff; Johnson, Jason M.; Herschorn, Sally D.; Brinton, Louise A.; Sherman, Mark E.

    2014-01-01

    Background Mammographic density (MD), the area of non-fatty appearing tissue divided by total breast area, is a strong breast cancer risk factor. Most MD analyses have employed visual categorizations or computer-assisted quantification, which ignore breast thickness. We explored MD volume and area, using a volumetric approach previously validated as predictive of breast cancer risk, in relation to risk factors among women undergoing breast biopsy. Methods Among 413 primarily white women, ages 40–65, undergoing diagnostic breast biopsies between 2007–2010 at an academic facility in Vermont, MD volume (cm3) was quantified in cranio-caudal views of the breast contralateral to the biopsy target using a density phantom, while MD area (cm2) was measured on the same digital mammograms using thresholding software. Risk factor associations with continuous MD measurements were evaluated using linear regression. Results Percent MD volume and area were correlated (r=0.81) and strongly and inversely associated with age, body mass index (BMI), and menopause. Both measures were inversely associated with smoking and positively associated with breast biopsy history. Absolute MD measures were correlated (r=0.46) and inversely related to age and menopause. Whereas absolute dense area was inversely associated with BMI, absolute dense volume was positively associated. Conclusions Volume and area MD measures exhibit some overlap in risk factor associations, but divergence as well, particularly for BMI. Impact Findings suggest that volume and area density measures differ in subsets of women; notably, among obese women, absolute density was higher with volumetric methods, suggesting that breast cancer risk assessments may vary for these techniques. PMID:25139935

  6. Breast self-examination and adherence to mammographic follow-up: an intriguing diptych after benign breast biopsy.

    PubMed

    Zografos, George C; Sergentanis, Theodoros N; Zagouri, Flora; Papadimitriou, Christos A; Domeyer, Philip; Kontogianni, Panagiota N; Nonni, Afroditi; Tsigris, Christos; Patsouris, Efstratios

    2010-01-01

    This study evaluates the effect of palpability upon breast self-examination (BSE) and adherence to annual mammogram after benign breast biopsy (BBB). Seven hundred and fifty-two women with palpable (WP, n = 359) or nonpalpable (WNP, n = 393) lesions were evaluated 2 years before and after BBB. BSE was considered adequate when it was performed at least once per month, and inadequate when it was performed with a frequency of less than once per month. Prebiopsy/postbiopsy adherence was characterized as inadequate when at least one session of mammographic examination was lost within the 2-prebiopsy/postbiopsy (including the last visit) years, respectively. The prebiopsy frequency of adequate BSE was higher in WP [49 (176 of 359) vs. 38.9% (153 of 393) for WNP; Pearson's chi2 (1) = 7.77, P = 0.005]. However, the opposite happened regarding the prebiopsy adherence to mammogram, as the frequency of adequate adherence was 64.1% (252 of 393) in WNP, but only 46.0% (165 of 359) in WP. After BBB, adherence to mammogram significantly increased in both groups, reaching 76.1% (299 of 393) for WNP and 65.2% (234 of 359) for WP. However, BSE increased significantly only in WNP. Regarding the WP group, the postBBB BSE did not exhibit any significant change. Noticeably, the aforementioned increase in BSE among WNP resulted in the disappearance of the initial WP-WNP discrepancy regarding BSE; the postBBB BSE did not differ between WP and WNP. However, concerning adherence to mammogram, the superiority of WNP versus WP persisted (76.1 vs. 65.2%, respectively). In conclusion WP and WNP may perceive BBB differently, as reflected upon the differentially modified patterns.

  7. Immunoassay and Nb2 lymphoma bioassay prolactin levels and mammographic density in premenopausal and postmenopausal women the Nurses' Health Studies.

    PubMed

    Rice, Megan S; Tworoger, Shelley S; Bertrand, Kimberly A; Hankinson, Susan E; Rosner, Bernard A; Feeney, Yvonne B; Clevenger, Charles V; Tamimi, Rulla M

    2015-01-01

    Higher circulating prolactin levels have been associated with higher percent mammographic density among postmenopausal women in some, but not all studies. However, few studies have examined associations with dense area and non-dense breast area breast or considered associations with prolactin Nb2 lymphoma cell bioassay levels. We conducted a cross-sectional study among 1,124 premenopausal and 890 postmenopausal women who were controls in breast cancer case-control studies nested in the Nurses' Health Study (NHS) and NHSII. Participants provided blood samples in 1989-1990 (NHS) or 1996-1999 (NHSII) and mammograms were obtained from around the time of blood draw. Multivariable linear models were used to assess the associations between prolactin levels (measured by immunoassay or bioassay) with percent density, dense area, and non-dense area. Among 1,124 premenopausal women, percent density, dense area, and non-dense area were not associated with prolactin immunoassay levels in multivariable models (p trends = 0.10, 0.18, and 0.69, respectively). Among 890 postmenopausal women, those with prolactin immunoassay levels in the highest versus lowest quartile had modestly, though significantly, higher percent density (difference = 3.01 percentage points, 95 % CI 0.22, 5.80) as well as lower non-dense area (p trend = 0.02). Among women with both immunoassay and bioassay levels, there were no consistent differences in the associations with percent density between bioassay and immunoassay levels. Postmenopausal women with prolactin immunoassay levels in the highest quartile had significantly higher percent density as well as lower non-dense area compared to those in the lowest quartile. Future studies should examine the underlying biologic mechanisms, particularly for non-dense area.

  8. 3D electron density imaging using single scattered x rays with application to breast CT and mammographic screening

    NASA Astrophysics Data System (ADS)

    van Uytven, Eric Peter

    Screening mammography is the current standard in detecting breast cancer. However, its fundamental disadvantage is that it projects a 3D object into a 2D image. Small lesions are difficult to detect when superimposed over layers of normal tissue. Commercial Computed Tomography (CT) produces a true 3D image yet has a limited role in mammography due to relatively low resolution and contrast. With the intent of enhancing mammography and breast CT, we have developed an algorithm which can produce 3D electron density images using a single projection. Imaging an object with x rays produces a characteristic scattered photon spectrum at the detector plane. A known incident beam spectrum, beam shape, and arbitrary 3D matrix of electron density values enable a theoretical scattered photon distribution to be calculated. An iterative minimization algorithm is used to make changes to the electron density voxel matrix to reduce regular differences between the theoretical and the experimentally measured distributions. The object is characterized by the converged electron density image. This technique has been validated in simulation using data produced by the EGSnrc Monte Carlo code system. At both mammographic and CT energies, a scanning polychromatic pencil beam was used to image breast tissue phantoms containing lesion-like inhomogeneities. The resulting Monte Carlo data is processed using a Nelder-Mead iterative algorithm (MATLAB) to produce the 3D matrix of electron density values. Resulting images have confirmed the ability of the algorithm to detect various 1x1x2.5 mm3 lesions with calcification content as low as 0.5% (p<0.005) at a dose comparable to mammography.

  9. Dense and Non-dense Mammographic Area and Risk of Breast Cancer by Age and Tumor Characteristics

    PubMed Central

    Bertrand, Kimberly A.; Scott, Christopher G.; Tamimi, Rulla M.; Jensen, Matthew R.; Pankratz, V. Shane; Norman, Aaron D.; Visscher, Daniel W.; Couch, Fergus J.; Shepherd, John; Chen, Yunn-Yi; Fan, Bo; Wu, Fang-Fang; Ma, Lin; Beck, Andrew H.; Cummings, Steven R.; Kerlikowske, Karla; Vachon, Celine M.

    2015-01-01

    Background Mammographic density (MD) is a strong breast cancer risk factor. We previously reported associations of percent MD with larger and node-positive tumors across all ages, and estrogen receptor (ER)-negative status among women ages <55 years. To provide insight into these associations, we examined the components of percent MD (dense area (DA) and non-dense area (NDA) with breast cancer subtypes. Methods Data were pooled from six studies including 4095 breast cancers and 8558 controls. DA and NDA were assessed from digitized film-screen mammograms and standardized across studies. Breast cancer odds by density phenotypes and age according to histopathological characteristics and receptor status were calculated using polytomous logistic regression. Results DA was associated with increased breast cancer risk [odds ratios (OR) for quartiles: 0.65, 1.00(Ref), 1.22, 1.55; p-trend <0.001] and NDA was associated with decreased risk [ORs for quartiles: 1.39, 1.00(Ref), 0.88, 0.72; p-trend <0.001] across all ages and invasive tumor characteristics. There were significant trends in the magnitude of associations of both DA and NDA with breast cancer by increasing tumor size (p-trend<0.001) but no differences by nodal status. Among women <55 years, DA was more strongly associated with increased risk of ER+ vs. ER− tumors [p-heterogeneity (het) = 0.02] while NDA was more strongly associated with decreased risk of ER− vs. ER+ tumors [p-het = 0.03]. Conclusions DA and NDA have differential associations with ER+ vs. ER− tumors that vary by age. Impact DA and NDA are important to consider when developing age- and subtype-specific risk models. PMID:25716949

  10. Randomized controlled trial of stereotactic 11-G vacuum-assisted core biopsy for the diagnosis and management of mammographic microcalcification

    PubMed Central

    Maxwell, Anthony J; Morris, Julie; Lim, Yit Y; Harake, MD Janick; Whiteside, Sigrid

    2016-01-01

    Objective: To compare the accuracy of 11-G vacuum-assisted biopsy (VAB) with 14-G core needle biopsy (CNB) to diagnose mammographic microcalcification (MM) and effect on surgical outcomes. Methods: Following ethical approval, VAB and CNB (control) were compared in a randomized prospective study for first-line diagnosis of MM and subsequent surgical outcomes in two breast-screening units. Participants gave written informed consent. Exclusions included comorbidity precluding surgery, prior ipsilateral breast cancer and lesions >40 mm requiring mastectomy as first surgical procedure. The final pathological diagnosis was compared with the initial biopsy result. Quality-of-life (QOL) questionnaires were administered at baseline, 2, 6 and 12 months. 110 participants were required to show a 25% improvement in diagnosis with VAB compared with CNB (90% power). Results: Eligibility was assessed for 787 cases; 129 females recalled from the National Health Service breast screening programme were randomized. Diagnostic accuracy of VAB was 86% and that of CNB was 84%. Using VAB, 2/14 (14.3%) cases upgraded from ductal carcinoma in situ to invasion at surgery and 3/19 (15.8%) using CNB. Following VAB 7/16 (44%) cases required repeat surgery vs 7/24 (29%) after CNB. Both groups recorded significant worsening of functional QOL measures and increased breast pain at follow-up. Conclusion: VAB and CNB were equally accurate at diagnosing MM, and no significant differences in surgical outcomes were observed. Advances in knowledge: The first randomized controlled study of VAB for diagnosis of microcalcification using digital mammography showed no difference in diagnostic accuracy of VAB and CNB, or in the proportion of participants needing repeat non-operative biopsy or second therapeutic operation to treat malignancy. PMID:26654214

  11. Learning and Teaching Qualitative Research with Qualitative Data Analysis Software.

    ERIC Educational Resources Information Center

    Mahlamaki-Kultanen, Seija

    This study examined the way qualitative data analysis software and virtual teaching methods can support the learning of qualitative research. Study methodology was based on phenomenology, and data were gathered in a pilot course on qualitative research methodology in which 22 adult part time graduate students participated. The course was built…

  12. Ecosystems and People: Qualitative Insights

    EPA Science Inventory

    Both qualitative and quantitative techniques are crucial in researching human impacts from ecological changes. This matches the importance of ?mixed methods? approaches in other disciplines. Qualitative research helps explore the relevancy and transferability of the foundational ...

  13. Imaging features of complex sclerosing lesions of the breast

    PubMed Central

    2014-01-01

    Purpose: The purpose of this study was to evaluate the imaging features of complex sclerosing lesions of the breast and to assess the rate of upgrade to breast cancer. Methods: From March 2008 to May 2012, seven lesions were confirmed as complex sclerosing lesions by ultrasonography-guided core needle biopsy. Final results by either surgical excision or follow-up imaging studies were reviewed to assess the rate of upgrade to breast cancer. Two radiologists retrospectively analyzed the imaging findings according to the Breast Imaging Reporting and Data System classification. Results: Five lesions underwent subsequent surgical excision and two of them revealed ductal carcinoma in situ (n=1) and invasive ductal carcinoma (n=1). Our study showed a breast cancer upgrade rate of 28.6% (2 of 7 lesions). Two lesions were stable on imaging follow-up beyond 1 year. The mammographic features included masses (n=4, 57.1%), architectural distortion (n=2, 28.6%), and focal asymmetry (n=1, 14.3%). Common B-mode ultrasonographic features were irregular shape (n=6, 85.7%), spiculated margin (n=5, 71.4 %), and hypoechogenicity (n=7, 100%). The final assessment categories were category 4 (n=6, 85.7%) and category 5 (n=1, 14.3%). Conclusion: The complex sclerosing lesions were commonly mass-like on mammography and showed the suspicious ultrasonographic features of category 4. Due to a high underestimation rate, all complex sclerosing lesions by core needle biopsy should be excised. PMID:24936496

  14. Approximate Qualitative Temporal Reasoning

    DTIC Science & Technology

    2001-01-01

    i.e., their boundaries can be placed in such a way that they coincide with the cell boundaries of the appropriate partition of the time-line. (Think of...respect to some appropriate partition of the time-line. For example, I felt well on Saturday. When I measured my temperature I had a fever on Monday and on...Bittner / Approximate Qualitative Temporal Reasoning 49 [27] I. A. Goralwalla, Y. Leontiev , M. T. Özsu, D. Szafron, and C. Combi. Temporal granularity for

  15. Stiffness of the microenvironment upregulates ERBB2 expression in 3D cultures of MCF10A within the range of mammographic density

    PubMed Central

    Cheng, Qingsu; Bilgin, Cemal Cagatay; Fonteney, Gerald; Chang, Hang; Henderson, Matthew; Han, Ju; Parvin, Bahram

    2016-01-01

    The effects of the stiffness of the microenvironment on the molecular response of 3D colony organization, at the maximum level of mammographic density (MD), are investigated. Phenotypic profiling reveals that 3D colony formation is heterogeneous and increased stiffness of the microenvironment, within the range of the MD, correlates with the increased frequency of aberrant 3D colony formation. Further integrative analysis of the genome-wide transcriptome and phenotypic profiling hypothesizes overexpression of ERBB2 in the premalignant MCF10A cell lines at a stiffness value that corresponds to the collagen component at high mammographic density. Subsequently, ERBB2 overexpression has been validated in the same cell line. Similar experiments with a more genetically stable cell line of 184A1 also revealed an increased frequency of aberrant colony formation with the increased stiffness; however, 184A1 did not demonstrate overexpression of ERBB2 at the same stiffness value of the high MD. These results suggest that stiffness exacerbates premalignant cell line of MCF10A. PMID:27383056

  16. A new Fourier transform based CBIR scheme for mammographic mass classification: a preliminary invariance assessment

    NASA Astrophysics Data System (ADS)

    Gundreddy, Rohith Reddy; Tan, Maxine; Qui, Yuchen; Zheng, Bin

    2015-03-01

    The purpose of this study is to develop and test a new content-based image retrieval (CBIR) scheme that enables to achieve higher reproducibility when it is implemented in an interactive computer-aided diagnosis (CAD) system without significantly reducing lesion classification performance. This is a new Fourier transform based CBIR algorithm that determines image similarity of two regions of interest (ROI) based on the difference of average regional image pixel value distribution in two Fourier transform mapped images under comparison. A reference image database involving 227 ROIs depicting the verified soft-tissue breast lesions was used. For each testing ROI, the queried lesion center was systematically shifted from 10 to 50 pixels to simulate inter-user variation of querying suspicious lesion center when using an interactive CAD system. The lesion classification performance and reproducibility as the queried lesion center shift were assessed and compared among the three CBIR schemes based on Fourier transform, mutual information and Pearson correlation. Each CBIR scheme retrieved 10 most similar reference ROIs and computed a likelihood score of the queried ROI depicting a malignant lesion. The experimental results shown that three CBIR schemes yielded very comparable lesion classification performance as measured by the areas under ROC curves with the p-value greater than 0.498. However, the CBIR scheme using Fourier transform yielded the highest invariance to both queried lesion center shift and lesion size change. This study demonstrated the feasibility of improving robustness of the interactive CAD systems by adding a new Fourier transform based image feature to CBIR schemes.

  17. Misclassification of Breast Imaging Reporting and Data System (BI-RADS) Mammographic Density and Implications for Breast Density Reporting Legislation.

    PubMed

    Gard, Charlotte C; Aiello Bowles, Erin J; Miglioretti, Diana L; Taplin, Stephen H; Rutter, Carolyn M

    2015-01-01

    USA states have begun legislating mammographic breast density reporting to women, requiring that women undergoing screening mammography who have dense breast tissue (Breast Imaging Reporting and Data System [BI-RADS] density c or d) receive written notification of their breast density; however, the impact that misclassification of breast density will have on this reporting remains unclear. The aim of this study was to assess reproducibility of the four-category BI-RADS density measure and examine its relationship with a continuous measure of percent density. We enrolled 19 radiologists, experienced in breast imaging, from a single integrated health care system. Radiologists interpreted 341 screening mammograms at two points in time 6 months apart. We assessed intra- and interobserver agreement in radiologists'; interpretations of BI-RADS density and explored whether agreement depended upon radiologist characteristics. We examined the relationship between BI-RADS density and percent density in a subset of 282 examinations. Intraradiologist agreement was moderate to substantial, with kappa varying across radiologists from 0.50 to 0.81 (mean = 0.69, 95% CI [0.63, 0.73]). Intraradiologist agreement was higher for radiologists with ≥10 years experience interpreting mammograms (difference in mean kappa = 0.10, 95% CI [0.01, 0.24]). Interradiologist agreement varied widely across radiologist pairs from slight to substantial, with kappa ranging from 0.02 to 0.72 (mean = 0.46, 95% CI [0.36, 0.55]). Of 145 examinations interpreted as "nondense" (BI-RADS density a or b) by the majority of radiologists, 82.8% were interpreted as "dense" (BI-RADS density c or d) by at least one radiologist. Of 187 examinations interpreted as "dense" by the majority of radiologists, 47.1% were interpreted as "nondense" by at least one radiologist. While the examinations of almost half of the women in our study were interpreted clinically as having BI-RADS density c or d, only about 10% of

  18. Adult weight gain, fat distribution and mammographic density in Spanish pre- and post-menopausal women (DDM-Spain).

    PubMed

    Pollán, Marina; Lope, Virginia; Miranda-García, Josefa; García, Milagros; Casanova, Francisco; Sánchez-Contador, Carmen; Santamariña, Carmen; Moreo, Pilar; Vidal, Carmen; Peris, Mercé; Moreno, María Pilar; Vázquez-Carrete, José Antonio; Collado, Francisca; Pedraz-Pingarrón, Carmen; Ascunce, Nieves; Salas-Trejo, Dolores; Aragonés, Nuria; Pérez-Gómez, Beatriz; Ruiz-Perales, Francisco

    2012-07-01

    High mammographic density (MD) is a phenotype risk marker for breast cancer. Body mass index (BMI) is inversely associated with MD, with the breast being a fat storage site. We investigated the influence of abdominal fat distribution and adult weight gain on MD, taking age, BMI and other confounders into account. Because visceral adiposity and BMI are associated with breast cancer only after menopause, differences in pre- and post-menopausal women were also explored. We recruited 3,584 women aged 45-68 years within the Spanish breast cancer screening network. Demographic, reproductive, family and personal history data were collected by purpose-trained staff, who measured current weight, height, waist and hip circumferences under the same protocol and with the same tools. MD was assessed in the left craniocaudal view using Boyd's Semiquantitative Scale. Association between waist-to-hip ratio, adult weight gain (difference between current weight and self-reported weight at 18 years) and MD was quantified by ordinal logistic regression, with random center-specific intercepts. Models were adjusted for age, BMI, breast size, time since menopause, parity, family history of breast cancer and hormonal replacement therapy use. Natural splines were used to describe the shape of the relationship between these two variables and MD. Waist-to-hip ratio was inversely associated with MD, and the effect was more pronounced in pre-menopausal (OR = 0.53 per 0.1 units; 95 % CI = 0.42-0.66) than in post-menopausal women (OR = 0.73; 95 % CI = 0.65-0.82) (P of heterogeneity = 0.010). In contrast, adult weight gain displayed a positive association with MD, which was similar in both groups (OR = 1.17 per 6 kg; 95 % CI = 1.11-1.23). Women who had gained more than 24 kg displayed higher MD (OR = 2.05; 95 % CI = 1.53-2.73). MD was also evaluated using Wolfe's and Tabár's classifications, with similar results being obtained. Once BMI, fat distribution and other confounders were considered

  19. Obstetric history and mammographic density: a population-based cross-sectional study in Spain (DDM-Spain).

    PubMed

    Lope, Virginia; Pérez-Gómez, Beatriz; Sánchez-Contador, Carmen; Santamariña, María Carmen; Moreo, Pilar; Vidal, Carmen; Laso, Maria Soledad; Ederra, Maria; Pedraz-Pingarrón, Carmen; González-Román, Isabel; García-López, Milagros; Salas-Trejo, Dolores; Peris, Mercé; Moreno, María Pilar; Vázquez-Carrete, Jose Antonio; Collado, Francisca; Aragonés, Nuria; Pollán, Marina

    2012-04-01

    High mammographic density (MD) is used as a phenotype risk marker for developing breast cancer. During pregnancy and lactation the breast attains full development, with a cellular-proliferation followed by a lobular-differentiation stage. This study investigates the influence of obstetric factors on MD among pre- and post-menopausal women. We enrolled 3,574 women aged 45-68 years who were participating in breast cancer screening programmes in seven screening centers. To measure MD, blind anonymous readings were taken by an experienced radiologist, using craniocaudal mammography and Boyd's semiquantitative scale. Demographic and reproductive data were directly surveyed by purpose-trained staff at the date of screening. The association between MD and obstetric variables was quantified by ordinal logistic regression, with screening centre introduced as a random effect term. We adjusted for age, number of children and body mass index, and stratified by menopausal status. Parity was inversely associated with density, the probability of having high MD decreased by 16% for each new birth (P value < 0.001). Among parous women, a positive association was detected with duration of lactation [>9 months: odds ratio (OR) = 1.33; 95% confidence interval (CI) = 1.02-1.72] and weight of first child (>3,500 g: OR = 1.32; 95% CI = 1.12-1.54). Age at first birth showed a different effect in pre- and post-menopausal women (P value for interaction = 0.030). No association was found among pre-menopausal women. However, in post-menopausal women the probability of having high MD increased in women who had their first child after the age of 30 (OR = 1.53; 95% CI = 1.17-2.00). A higher risk associated with birth of twins was also mainly observed in post-menopausal women (OR = 2.02; 95% CI = 1.18-3.46). Our study shows a greater prevalence of high MD in mothers of advanced age at first birth, those who had twins, those who have breastfed for longer periods, and mothers whose first child had

  20. Situating methodology within qualitative research.

    PubMed

    Kramer-Kile, Marnie L

    2012-01-01

    Qualitative nurse researchers are required to make deliberate and sometimes complex methodological decisions about their work. Methodology in qualitative research is a comprehensive approach in which theory (ideas) and method (doing) are brought into close alignment. It can be difficult, at times, to understand the concept of methodology. The purpose of this research column is to: (1) define qualitative methodology; (2) illuminate the relationship between epistemology, ontology and methodology; (3) explicate the connection between theory and method in qualitative research design; and 4) highlight relevant examples of methodological decisions made within cardiovascular nursing research. Although there is no "one set way" to do qualitative research, all qualitative researchers should account for the choices they make throughout the research process and articulate their methodological decision-making along the way.

  1. Mammographic density and risk of breast cancer according to tumor characteristics and mode of detection: a Spanish population-based case-control study

    PubMed Central

    2013-01-01

    Introduction It is not clear whether high mammographic density (MD) is equally associated with all subtypes of breast cancer (BC). We investigated the association between MD and subsequent BC, considering invasiveness, means of detection, pathologic subtype, and the time elapsed since mammographic exploration and BC diagnosis. Methods BC cases occurring in the population of women who attended screening from 1997 through 2004 in Navarre, a Spanish region with a fully consolidated screening program, were identified via record linkage with the Navarre Cancer Registry (n = 1,172). Information was extracted from the records of their first attendance at screening in that period. For each case, we randomly selected four controls, matched by screening round, year of birth, and place of residence. Cases were classified according to invasiveness (ductal carcinoma in situ (DCIS) versus invasive tumors), pathologic subtype (considering hormonal receptors and HER2), and type of diagnosis (screen-detected versus interval cases). MD was evaluated by a single, experienced radiologist by using a semiquantitative scale. Data on BC risk factors were obtained by the screening program in the corresponding round. The association between MD and tumor subtype was assessed by using conditional logistic regression. Results MD was clearly associated with subsequent BC. The odds ratio (OR) for the highest MD category (MD >75%) compared with the reference category (MD <10%) was similar for DCIS (OR = 3.47; 95% CI = 1.46 to 8.27) and invasive tumors (OR = 2.95; 95% CI = 2.01 to 4.35). The excess risk was particularly high for interval cases (OR = 7.72; 95% CI = 4.02 to 14.81) in comparison with screened detected tumors (OR = 2.17; 95% CI = 1.40 to 3.36). Sensitivity analyses excluding interval cases diagnosed in the first year after MD assessment or immediately after an early recall to screening yielded similar results. No differences were seen regarding pathologic subtypes. The excess risk

  2. Qualitative research in transfusion medicine.

    PubMed

    Arnold, E; Lane, S

    2011-10-01

    Transfusion medicine research has traditionally employed quantitative methods to answer clinical research questions. Increasingly, qualitative research methods are being used in the field to address a wide variety of research questions in areas such as blood donation, transfusion practices and policy development. This article describes the key characteristics, methodologies and methods of qualitative research and draws on examples to show how qualitative research approaches have been applied in the field of transfusion medicine. It is hoped that this overview will inform and encourage the application of qualitative research in the field of transfusion medicine.

  3. Mentoring Qualitative Research Authors Globally: "The Qualitative Report" Experience

    ERIC Educational Resources Information Center

    Chenail, Ronald J.; St. George, Sally; Wulff, Dan; Duffy, Maureen; Laughlin, Martha; Warner, Kate; Sahni, Tarmeen

    2007-01-01

    Authoring quality qualitative inquiry is a challenge for most researchers. A lack of local mentors can make writing even more difficult. To meet this need, The "Qualitative Report (TQR)" has helped authors from around the world develop their papers into published articles. "TQR" editorial team members will discuss the history of the journal, their…

  4. General features

    SciTech Connect

    Wallace, R.E.

    1990-01-01

    The San Andreas fault system, a complex of faults that display predominantly large-scale strike slip, is part of an even more complex system of faults, isolated segments of the East Pacific Rise, and scraps of plates lying east of the East Pacific Rise that collectively separate the North American plate from the Pacific plate. This chapter briefly describes the San Andreas fault system, its setting along the Pacific Ocean margin of North America, its extent, and the patterns of faulting. Only selected characteristics are described, and many features are left for depictions on maps and figures.

  5. Qualitative interviewing as measurement.

    PubMed

    Paley, John

    2010-04-01

    The attribution of beliefs and other propositional attitudes is best understood as a form of measurement, however counter-intuitive this may seem. Measurement theory does not require that the thing measured should be a magnitude, or that the calibration of the measuring instrument should be numerical. It only requires a homomorphism between the represented domain and the representing domain. On this basis, maps measure parts of the world, usually geographical locations, and 'belief' statements measure other parts of the world, namely people's aptitudes. Having outlined an argument for this view, I deal with an obvious objection to it: that self-attribution of belief cannot be an exercise in measurement, because we are all aware, from introspection, that our beliefs have an intrinsically semantic form. Subsequently, I turn to the philosophical and methodological ramifications of the measurement theoretic view. I argue, first, that it undermines at least one version of constructivism and, second, that it provides an effective alternative to the residually Cartesian philosophy that underpins much qualitative research. Like other anti-Cartesian strategies, belief-attribution-as-measurement implies that the objective world is far more knowable than the subjective one, and that reality is ontologically prior to meaning. I regard this result as both plausible and welcome.

  6. A feasibility study of X-ray phase-contrast mammographic tomography at the Imaging and Medical beamline of the Australian Synchrotron.

    PubMed

    Nesterets, Yakov I; Gureyev, Timur E; Mayo, Sheridan C; Stevenson, Andrew W; Thompson, Darren; Brown, Jeremy M C; Kitchen, Marcus J; Pavlov, Konstantin M; Lockie, Darren; Brun, Francesco; Tromba, Giuliana

    2015-11-01

    Results are presented of a recent experiment at the Imaging and Medical beamline of the Australian Synchrotron intended to contribute to the implementation of low-dose high-sensitivity three-dimensional mammographic phase-contrast imaging, initially at synchrotrons and subsequently in hospitals and medical imaging clinics. The effect of such imaging parameters as X-ray energy, source size, detector resolution, sample-to-detector distance, scanning and data processing strategies in the case of propagation-based phase-contrast computed tomography (CT) have been tested, quantified, evaluated and optimized using a plastic phantom simulating relevant breast-tissue characteristics. Analysis of the data collected using a Hamamatsu CMOS Flat Panel Sensor, with a pixel size of 100 µm, revealed the presence of propagation-based phase contrast and demonstrated significant improvement of the quality of phase-contrast CT imaging compared with conventional (absorption-based) CT, at medically acceptable radiation doses.

  7. Using Numbers in Qualitative Research

    ERIC Educational Resources Information Center

    Maxwell, Joseph A.

    2010-01-01

    The use of numerical/quantitative data in qualitative research studies and reports has been controversial. Prominent qualitative researchers such as Howard Becker and Martyn Hammersley have supported the inclusion of what Becker called "quasi-statistics": simple counts of things to make statements such as "some," "usually," and "most" more…

  8. A case-control study to assess the impact of mammographic density on breast cancer risk in women aged 40-49 at intermediate familial risk.

    PubMed

    Assi, Valentina; Massat, Nathalie J; Thomas, Susan; MacKay, James; Warwick, Jane; Kataoka, Masako; Warsi, Iqbal; Brentnall, Adam; Warren, Ruth; Duffy, Stephen W

    2015-05-15

    Mammographic density is a strong risk factor for breast cancer, but its potential application in risk management is not clear, partly due to uncertainties about its interaction with other breast cancer risk factors. We aimed to quantify the impact of mammographic density on breast cancer risk in women aged 40-49 at intermediate familial risk of breast cancer (average lifetime risk of 23%), in particular in premenopausal women, and to investigate its relationship with other breast cancer risk factors in this population. We present the results from a case-control study nested with the FH01 cohort study of 6,710 women mostly aged 40-49 at intermediate familial risk of breast cancer. One hundred and three cases of breast cancer were age-matched to one or two controls. Density was measured by semiautomated interactive thresholding. Absolute density, but not percent density, was a significant risk factor for breast cancer in this population after adjusting for area of nondense tissue (OR per 10 cm(2) = 1.07, 95% CI 1.00-1.15, p = 0.04). The effect was stronger in premenopausal women, who made up the majority of the study population. Absolute density remained a significant predictor of breast cancer risk after adjusting for age at menarche, age at first live birth, parity, past or present hormone replacement therapy, and the Tyrer-Cuzick 10-year relative risk estimate of breast cancer. Absolute density can improve breast cancer risk stratification and delineation of high-risk groups alongside the Tyrer-Cuzick 10-year relative risk estimate.

  9. Fractal dimension and lacunarity analysis of mammographic patterns in assessing breast cancer risk related to HRT treated population: a longitudinal and cross-sectional study

    NASA Astrophysics Data System (ADS)

    Karemore, Gopal; Nielsen, Mads

    2009-02-01

    Structural texture measures are used to address the aspect of breast cancer risk assessment in screening mammograms. The current study investigates whether texture properties characterized by local Fractal Dimension (FD) and Lacunarity contribute to asses breast cancer risk. FD represents the complexity while the Lacunarity characterize the gappiness of a fractal. Our cross-sectional case-control study includes mammograms of 50 patients diagnosed with breast cancer in the subsequent 2-4 years and 50 matched controls. The longitudinal double blind placebo controlled HRT study includes 39 placebo and 36 HRT treated volunteers for two years. ROIs with same dimension (250*150 pixels) were created behind the nipple region on these radiographs. Box counting method was used to calculate the fractal dimension (FD) and the Lacunarity. Paired t-test and Pearson correlation coefficient were calculated. It was found that there were no differences between cancer and control group for FD (P=0.8) and Lacunarity (P=0.8) in crosssectional study whereas earlier published heterogeneity examination of radiographs (BC-HER) breast cancer risk score separated groups (p=0.002). In the longitudinal study, FD decreased significantly (P<0.05) in the HRT treated population while Lacunarity remained insignificant (P=0.2). FD is negatively correlated to Lacunarity (-0.74, P<0.001), BIRADS (-0.34, P<0.001) and Percentage Density (-0.41, P<0.001). FD is invariant to the mammographic texture change from control to cancer population but marginally varying in HRT treated population. This study yields no evidence that lacunarity or FD are suitable surrogate markers of mammographic heterogeneity as they neither pick up breast cancer risk, nor show good sensitivity to HRT.

  10. Effect of pixel resolution on texture features of breast masses in mammograms.

    PubMed

    Rangayyan, Rangaraj M; Nguyen, Thanh M; Ayres, Fábio J; Nandi, Asoke K

    2010-10-01

    The effect of pixel resolution on texture features computed using the gray-level co-occurrence matrix (GLCM) was analyzed in the task of discriminating mammographic breast lesions as benign masses or malignant tumors. Regions in mammograms related to 111 breast masses, including 65 benign masses and 46 malignant tumors, were analyzed at pixel sizes of 50, 100, 200, 400, 600, 800, and 1,000 μm. Classification experiments using each texture feature individually provided accuracy, in terms of the area under the receiver operating characteristics curve (AUC), of up to 0.72. Using the Bayesian classifier and the leave-one-out method, the AUC obtained was in the range 0.73 to 0.75 for the pixel resolutions of 200 to 800 μm, with 14 GLCM-based texture features using adaptive ribbons of pixels around the boundaries of the masses. Texture features computed using the ribbons resulted in higher classification accuracy than the same features computed using the corresponding regions within the mass boundaries. The t test was applied to AUC values obtained using 100 repetitions of random splitting of the texture features from the ribbons of masses into the training and testing sets. The texture features computed with the pixel size of 200 μm provided the highest average AUC with statistically highly significant differences as compared to all of the other pixel sizes tested, except 100 μm.

  11. Positivism and qualitative nursing research.

    PubMed

    Paley, J

    2001-01-01

    Despite the hostility to positivism shown by qualitative methodologists in nursing, as in other disciplines, the epistemological and ontological instincts of qualitative researchers seem to coincide with those of the positivists, especially Bayesian positivists. This article suggests that positivists and qualitative researchers alike are pro-observation, proinduction, pro-plausibility and pro-subjectivity. They are also anti-cause, anti-realist, anti-explanation, anti-correspondence, anti-truth. In only one respect is there a significant difference between positivist and qualitative methodologists: most positivists have believed that, methodologically, the natural sciences and the social sciences are the same; most qualitative researchers are adamant that they are not. However, if positivism fails as a philosophy of the natural sciences (which it probably does), it might well succeed as a philosophy of the social sciences, just because there is a methodological watershed between the two. Reflex antagonism to positivism might therefore be a major obstacle to understanding the real reasons why qualitative research and the natural sciences are methodologically divergent; and less hostility on the part of qualitative nurse researchers might bring certain advantages in its wake.

  12. Trajectory constraints in qualitative simulation

    SciTech Connect

    Brajnik, G.; Clancy, D.J.

    1996-12-31

    We present a method for specifying temporal constraints on trajectories of dynamical systems and enforcing them during qualitative simulation. This capability can be used to focus a simulation, simulate non-autonomous and piecewise-continuous systems, reason about boundary condition problems and incorporate observations into the simulation. The method has been implemented in TeQSIM, a qualitative simulator that combines the expressive power of qualitative differential equations with temporal logic. It interleaves temporal logic model checking with the simulation to constrain and refine the resulting predicted behaviors and to inject discontinuous changes into the simulation.

  13. Qualitative tools and experimental philosophy

    PubMed Central

    Andow, James

    2016-01-01

    Abstract Experimental philosophy brings empirical methods to philosophy. These methods are used to probe how people think about philosophically interesting things such as knowledge, morality, and freedom. This paper explores the contribution that qualitative methods have to make in this enterprise. I argue that qualitative methods have the potential to make a much greater contribution than they have so far. Along the way, I acknowledge a few types of resistance that proponents of qualitative methods in experimental philosophy might encounter, and provide reasons to think they are ill-founded.

  14. Contemporary Qualitative Research Methodologies and Issues in Literacy Education

    ERIC Educational Resources Information Center

    Tobin, Joseph; Steinkuehler, Constance A.; Black, Rebecca W.; Clinton, Katherine A.; Hinchman, Kathleen A.; Dillon, Deborah R.

    2005-01-01

    Scholars who are drawn to qualitative research methodologies represent a diverse group of disciplines and fields. They also represent themselves as researchers and the theoretical frameworks in which they work quite differently. Indeed, it was this diversity in representation that initially motivated us to propose a New Directions feature on…

  15. Doing qualitative research in general practice: methodological utility and engagement.

    PubMed

    Jaye, Chrystal

    2002-10-01

    General practice uses an eclectic range of research methodology. This includes increasing reliance upon qualitative research methods. There seem to be two distinct treatments of qualitative research within primary care and, in particular, within general practice research. The first is characterized by a purely utilitarian and technical focus, using a qualitative method because it is the most appropriate means of realizing the aims of the research, while the second is characterized by in-depth engagement with the philosophical and paradigmatic aspects of qualitative methodology. In-depth engagement with methodology and theory, and theory building, is an important aspect of masterate and doctoral research within social sciences such as education and anthropology, and in the discipline of nursing, but has not been a feature of qualitative research in medicine. A practical difficulty encountered within postgraduate programmes such as the one in which the author teaches is that when innovative qualitative techniques are used by GPs in their postgraduate research dissertations and theses, it is often beyond GP examiners' own knowledge and experience, yet it fails to measure up to standards established in social sciences, particularly in sociology and anthropology where in-depth reflexive engagement with the theory and philosophy of qualitative methodology is expected. This paper suggests that the value of in-depth engagement with methodology when conducting qualitative research results in creative and innovative ways of conducting research that are consonant with the nature of general practice itself, and strengthens research findings. Therefore, as teachers of research methods and supervisors of research theses, it is important to encourage students conducting qualitative research to engage fully with theoretical and methodological issues.

  16. So you want to do research? 3. An introduction to qualitative methods.

    PubMed

    Meadows, Keith A

    2003-10-01

    This article describes some of the key issues in the use of qualitative research methods. Starting with a description of what qualitative research is and outlining some of the distinguishing features between quantitative and qualitative research, examples of the type of setting where qualitative research can be applied are provided. Methods of collecting information through in-depth interviews and group discussions are discussed in some detail, including issues around sampling and recruitment, the use of topic guides and techniques to encourage participants to talk openly. An overview on the analysis of qualitative data discusses aspects on data reduction, display and drawing conclusions from the data. Approaches to ensuring rigour in the collection, analysis and reporting of qualitative research are discussed and the concepts of credibility, transferability, dependability and confirmability are described. Finally, guidelines for the reporting of qualitative research are outlined and the need to write for a particular audience is discussed.

  17. Exploring the Relevance of Qualitative Research Synthesis to Higher Education Research and Practice

    ERIC Educational Resources Information Center

    Major, Claire; Savin-Baden, Maggi

    2010-01-01

    This paper proposes the importance of qualitative research synthesis to the field of higher education. It examines seven key texts that undertake synthesis in this field and compares essential features and elements across studies. The authors indicate strengths of the approaches and highlight ways forward for using qualitative research synthesis…

  18. Qualitative methods for assessing risk

    SciTech Connect

    Mahn, J.A.; Hannaman, G.W.; Kryska, P.

    1995-03-01

    The purpose of this document is to describe a qualitative risk assessment process that supplements the requirements of DOE/AL 5481.1B. Although facility managers have a choice of assessing risk either quantitatively or qualitatively, trade offs are involved in making the most appropriate choice for a given application. The results that can be obtained from a quantitative risk assessment are significantly more robust than those results derived from a qualitative approach. However, the advantages derived from quantitative risk assessment are achieved at a greater expenditure of money, time and convenience. This document provides the elements of a framework for performing a much less costly qualitative risk assessment, while retaining the best attributes of quantitative methods. The approach discussed herein will; (1) provide facility managers with the tools to prepare consistent, site wide assessments, and (2) aid the reviewers who may be tasked to evaluate the assessments. Added cost/benefit measures of the qualitative methodology include the identification of mechanisms for optimally allocating resources for minimizing risk in an expeditious, and fiscally responsible manner.

  19. Qualitative research as methodical hermeneutics.

    PubMed

    Rennie, David L

    2012-09-01

    The proportion of publications of qualitative research in mainstream psychology journals is small. Thus, in terms of this important criterion, despite its recent rapid growth, qualitative research is marginalized in psychology. The author suggests that contributing to this situation is the lack of a coherent and unifying methodology of qualitative research methods that elucidates their credibility. He groups the many qualitative research methods into 3 main kinds, then applies to them 4 propositions offered as such a methodology: (1) Qualitative research is hermeneutical, entailing application of the method of the hermeneutic circle to text about experience and/or action. (2) Implicit in the use of the hermeneutic circle method is the activity of educing and articulating the meaning of text, an activity that modifies and interacts with C. S. Peirce's (1965, 1966) logical operations of abduction, theorematic deduction, and induction. (3) The cycling of these 4 moments enables demonstration, achieved rhetorically, of the validity of the understandings resulting from the exegesis of the text under study. (4) This demonstrative rhetoric is enhanced when researchers disclose reflexively those aspects of their perspectives they judge to have most relevant bearing on their understandings. The author compares abduction as formulated here with other recent uptakes of it. As an installment on the generality of the methodology, he explores its fit with the descriptive phenomenological psychological method, conversation analysis, and thematic analysis.

  20. Commentary: Writing and evaluating qualitative research reports

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An overview of qualitative methods is provided, particularly for reviewers and authors who may be less familiar with qualitative research. A question and answer format is used to address considerations for writing and evaluating qualitative research. When producing qualitative research, individuals ...

  1. Doing Qualitative Research in Education Settings.

    ERIC Educational Resources Information Center

    Hatch, J. Amos

    This book, designed for novice researchers, provides a step-by-step guide to the development of a research project. It emphasizes learning how to do qualitative work and provides specific examples from real studies. The chapters are: (1) "Deciding To Do a Qualitative Study"; (2) "Designing Qualitative Studies"; (3) "Collecting Qualitative Data";…

  2. Considerations for Readers of Qualitative Research. Editorial.

    ERIC Educational Resources Information Center

    Ferguson, Dianne L.; Halle, James W.

    1995-01-01

    This article distinguishes between "using qualitative methods" and "doing qualitative research." It highlights the qualitative approaches of the authors of five articles in this issue and considers the challenges of this type of qualitative research manuscript for the editorial process. (DB)

  3. Disentangling the roles of mammographic screening and HRT in recent breast cancer incidence trends in italy by analyses based on calendar time and time since screening activation.

    PubMed

    Crocetti, Emanuele; Buzzoni, Carlotta; Falcini, Fabio; Cortesi, Laura; De Lisi, Vincenzo; Ferretti, Stefano; Tumino, Rosario; Russo, Antonio; Paci, Eugenio

    2010-01-01

    The aim of the study was to evaluate the roles of screening activation and hormone replacement therapy discontinuation on the recent declining breast cancer incidence trends in Italy. We analyzed 41,358 invasive female breast cancers incident during 1991-2004 in six Italian population-based cancer registries. Overall and age-specific incidence trends were evaluated using Joinpoint analysis. In addition to calendar years, data were analyzed on a years-since-screening-activation basis. Annual percentage change of standardized rates was computed. There were statistically significant increasing trends for women 40-44 and 45-49 years that did not change after screening activation. On the contrary, for women 50-69 years old and for those 70+ years, the increasing trends flattened around 2 years after screening activation. The prevalence of hormone replacement therapy use in Italy is and was rather low. In conclusion, the recent tendency toward stabilization observed in Italy for female breast cancer incidence rates in women aged 50 years or more follows the introduction of mammographic screening.

  4. Development of active matrix flat panel imagers incorporating thin layers of polycrystalline HgI(2) for mammographic x-ray imaging.

    PubMed

    Jiang, Hao; Zhao, Qihua; Antonuk, Larry E; El-Mohri, Youcef; Gupta, Tapan

    2013-02-07

    Active matrix flat-panel imagers (AMFPIs) offer many advantages and have become ubiquitous across a wide variety of medical x-ray imaging applications. However, for mammography, the imaging performance of conventional AMFPIs incorporating CsI:Tl scintillators or a-Se photoconductors is limited by their relatively modest signal-to-noise ratio (SNR), particularly at low x-ray exposures or high spatial resolution. One strategy for overcoming this limitation involves the use of a high gain photoconductor such as mercuric iodide (HgI(2)) which has the potential to improve the SNR by virtue of its low effective work function (W(EFF)). In this study, the performance of direct-detection AMFPI prototypes employing relatively thin layers of polycrystalline HgI(2) operated under mammographic irradiation conditions over a range of 0.5 to 16.0 mR is presented. High x-ray sensitivity (corresponding to W(EFF) values of ∼19 eV), low dark current (<0.1 pA mm(-2)) and good spatial resolution, largely limited by the size of the pixel pitch, were observed. For one prototype, a detective quantum efficiency of ∼70% was observed at an x-ray exposure of ∼0.5 mR at 26 kVp.

  5. Caregiving: A Qualitative Concept Analysis

    ERIC Educational Resources Information Center

    Hermanns, Melinda; Mastel-Smith, Beth

    2012-01-01

    A common definition of caregiving does not exist. In an attempt to define the concept of caregiving, the authors used a hybrid qualitative model of concept development to analyze caregiving. The model consists of three phases: (a) theoretical, (b) fieldwork, and (c) analytical. The theoretical phase involves conducting an interdisciplinary…

  6. Qualitative Assessment of Arts Education

    ERIC Educational Resources Information Center

    Stake, Robert; Munson, April

    2008-01-01

    Exploring the complicated issues of assessment in the arts, the authors discuss assessment of arts education and arts programs from a qualitative perspective: experiential, naturalistic, and ethnographic interpretation. With special attention to the practices of teaching, learning, and administration of education in the arts, quality is sought…

  7. Determining Validity in Qualitative Inquiry.

    ERIC Educational Resources Information Center

    Creswell, John W.; Miller, Dana L.

    2000-01-01

    Suggests that the choice of validity procedures in qualitative inquiry is governed by two perspectives: the lens researchers choose to validate their studies and the researchers' paradigm assumptions. The article advances a two-dimensional framework to help researchers identify appropriate validity procedures for their studies. Nine validity…

  8. Teaching Reflexivity in Qualitative Interviewing

    ERIC Educational Resources Information Center

    Hsiung, Ping-Chun

    2008-01-01

    Reflexivity has gained paramount status in qualitative inquiry. It is central to debates on subjectivity, objectivity, and, ultimately, the scientific foundation of social science knowledge and research. Although much work on doing reflexivity by researchers and practitioners has been published, scholars have only recently begun to explore how one…

  9. Historical Perspectives toward Qualitative Research

    ERIC Educational Resources Information Center

    Watras, Joseph

    2009-01-01

    The keynote address on which this article is based considers four stages or types of studies that qualitative researchers undertake in the field of education. The reason that I explored this focus was to illustrate the benefits and the dangers of designing studies to serve policy makers. The research that I selected sought to uncover information…

  10. Consensual Qualitative Research: An Update

    ERIC Educational Resources Information Center

    Hill, Clara E.; Knox, Sarah; Thompson, Barbara J.; Williams, Elizabeth Nutt; Hess, Shirley A.; Ladany, Nicholas

    2005-01-01

    The authors reviewed the application of consensual qualitative research (CQR) in 27 studies published since the method's introduction to the field in 1997 by C. E. Hill, B. J. Thompson, and E. N. Williams (1997). After first describing the core components and the philosophical underpinnings of CQR, the authors examined how it has been applied in…

  11. Reconsidering Constructivism in Qualitative Research

    ERIC Educational Resources Information Center

    Lee, Cheu-Jey George

    2012-01-01

    This article examines constructivism, a paradigm in qualitative research that has been propagated by Egon Guba, Yvonna Lincoln, and Norman Denzin. A distinction is made between whether the basic presuppositions of constructivism are credible compared to those of a competing paradigm and whether constructivism's beliefs are internally consistent.…

  12. Qualitative Research in Rehabilitation Counseling

    ERIC Educational Resources Information Center

    Hanley-Maxwell, Cheryl; Al Hano, Ibrahim; Skivington, Michael

    2007-01-01

    Qualitative research approaches offer rehabilitation scholars and practitioners avenues into understanding the lives and experiences of people with disabilities and those people and systems with whom they interact. The methods used often parallel those used in counseling and appear to be well matched with the field of rehabilitation counseling.…

  13. Online feature selection with streaming features.

    PubMed

    Wu, Xindong; Yu, Kui; Ding, Wei; Wang, Hao; Zhu, Xingquan

    2013-05-01

    We propose a new online feature selection framework for applications with streaming features where the knowledge of the full feature space is unknown in advance. We define streaming features as features that flow in one by one over time whereas the number of training examples remains fixed. This is in contrast with traditional online learning methods that only deal with sequentially added observations, with little attention being paid to streaming features. The critical challenges for Online Streaming Feature Selection (OSFS) include 1) the continuous growth of feature volumes over time, 2) a large feature space, possibly of unknown or infinite size, and 3) the unavailability of the entire feature set before learning starts. In the paper, we present a novel Online Streaming Feature Selection method to select strongly relevant and nonredundant features on the fly. An efficient Fast-OSFS algorithm is proposed to improve feature selection performance. The proposed algorithms are evaluated extensively on high-dimensional datasets and also with a real-world case study on impact crater detection. Experimental results demonstrate that the algorithms achieve better compactness and higher prediction accuracy than existing streaming feature selection algorithms.

  14. An overview of bipolar qualitative decision rules

    NASA Astrophysics Data System (ADS)

    Bonnefon, Jean-Francois; Dubois, Didier; Fargier, Hélène

    Making a good decision is often a matter of listing and comparing positive and negative arguments, as studies in cognitive psychology have shown. In such cases, the evaluation scale should be considered bipolar, that is, negative and positive values are explicitly distinguished. Generally, positive and negative features are evaluated separately, as done in Cumulative Prospect Theory. However, contrary to the latter framework that presupposes genuine numerical assessments, decisions are often made on the basis of an ordinal ranking of the pros and the cons, and focusing on the most salient features, i.e., the decision process is qualitative. In this paper, we report on a project aiming at characterizing several decision rules, based on possibilistic order of magnitude reasoning, and tailored for the joint handling of positive and negative affects, and at testing their empirical validity. The simplest rules can be viewed as extensions of the maximin and maximax criteria to the bipolar case and, like them, suffer from a lack of discrimination power. More decisive rules that refine them are also proposed. They account for both the principle of Pareto-efficiency and the notion of order of magnitude reasoning. The most decisive one uses a lexicographic ranking of the pros and cons. It comes down to a special case of Cumulative Prospect Theory, and subsumes the “Take the best” heuristic.

  15. Obstructions to Sampling Qualitative Properties

    PubMed Central

    Reimers, Arne C.

    2015-01-01

    Background Sampling methods have proven to be a very efficient and intuitive method to understand properties of complicated spaces that cannot easily be computed using deterministic methods. Therefore, sampling methods became a popular tool in the applied sciences. Results Here, we show that sampling methods are not an appropriate tool to analyze qualitative properties of complicated spaces unless RP = NP. We illustrate these results on the example of the thermodynamically feasible flux space of genome-scale metabolic networks and show that with artificial centering hit and run (ACHR) not all reactions that can have variable flux rates are sampled with variables flux rates. In particular a uniform sample of the flux space would not sample the flux variabilities completely. Conclusion We conclude that unless theoretical convergence results exist, qualitative results obtained from sampling methods should be considered with caution and if possible double checked using a deterministic method. PMID:26287384

  16. Observing Reel Life: Using Feature Films To Teach Ethnographic Methods.

    ERIC Educational Resources Information Center

    Leblanc, Lauraine

    1998-01-01

    Extends the methods of using film as a tool to teach content analysis and examines the use of feature films in teaching ethnographic methods. Explores how feature films are a valuable pedagogical tool in qualitative methods instruction by drawing from an assignment developed for a course on youth subcultures. (DSK)

  17. A novel approach for detection and classification of mammographic microcalcifications using wavelet analysis and extreme learning machine.

    PubMed

    Malar, E; Kandaswamy, A; Chakravarthy, D; Giri Dharan, A

    2012-09-01

    The objective of this paper is to reveal the effectiveness of wavelet based tissue texture analysis for microcalcification detection in digitized mammograms using Extreme Learning Machine (ELM). Microcalcifications are tiny deposits of calcium in the breast tissue which are potential indicators for early detection of breast cancer. The dense nature of the breast tissue and the poor contrast of the mammogram image prohibit the effectiveness in identifying microcalcifications. Hence, a new approach to discriminate the microcalcifications from the normal tissue is done using wavelet features and is compared with different feature vectors extracted using Gray Level Spatial Dependence Matrix (GLSDM) and Gabor filter based techniques. A total of 120 Region of Interests (ROIs) extracted from 55 mammogram images of mini-Mias database, including normal and microcalcification images are used in the current research. The network is trained with the above mentioned features and the results denote that ELM produces relatively better classification accuracy (94%) with a significant reduction in training time than the other artificial neural networks like Bayesnet classifier, Naivebayes classifier, and Support Vector Machine. ELM also avoids problems like local minima, improper learning rate, and over fitting.

  18. Wavelet-Based 3D Reconstruction of Microcalcification Clusters from Two Mammographic Views: New Evidence That Fractal Tumors Are Malignant and Euclidean Tumors Are Benign

    PubMed Central

    Batchelder, Kendra A.; Tanenbaum, Aaron B.; Albert, Seth; Guimond, Lyne; Kestener, Pierre; Arneodo, Alain; Khalil, Andre

    2014-01-01

    The 2D Wavelet-Transform Modulus Maxima (WTMM) method was used to detect microcalcifications (MC) in human breast tissue seen in mammograms and to characterize the fractal geometry of benign and malignant MC clusters. This was done in the context of a preliminary analysis of a small dataset, via a novel way to partition the wavelet-transform space-scale skeleton. For the first time, the estimated 3D fractal structure of a breast lesion was inferred by pairing the information from two separate 2D projected mammographic views of the same breast, i.e. the cranial-caudal (CC) and mediolateral-oblique (MLO) views. As a novelty, we define the “CC-MLO fractal dimension plot”, where a “fractal zone” and “Euclidean zones” (non-fractal) are defined. 118 images (59 cases, 25 malignant and 34 benign) obtained from a digital databank of mammograms with known radiologist diagnostics were analyzed to determine which cases would be plotted in the fractal zone and which cases would fall in the Euclidean zones. 92% of malignant breast lesions studied (23 out of 25 cases) were in the fractal zone while 88% of the benign lesions were in the Euclidean zones (30 out of 34 cases). Furthermore, a Bayesian statistical analysis shows that, with 95% credibility, the probability that fractal breast lesions are malignant is between 74% and 98%. Alternatively, with 95% credibility, the probability that Euclidean breast lesions are benign is between 76% and 96%. These results support the notion that the fractal structure of malignant tumors is more likely to be associated with an invasive behavior into the surrounding tissue compared to the less invasive, Euclidean structure of benign tumors. Finally, based on indirect 3D reconstructions from the 2D views, we conjecture that all breast tumors considered in this study, benign and malignant, fractal or Euclidean, restrict their growth to 2-dimensional manifolds within the breast tissue. PMID:25222610

  19. Wavelet-based 3D reconstruction of microcalcification clusters from two mammographic views: new evidence that fractal tumors are malignant and Euclidean tumors are benign.

    PubMed

    Batchelder, Kendra A; Tanenbaum, Aaron B; Albert, Seth; Guimond, Lyne; Kestener, Pierre; Arneodo, Alain; Khalil, Andre

    2014-01-01

    The 2D Wavelet-Transform Modulus Maxima (WTMM) method was used to detect microcalcifications (MC) in human breast tissue seen in mammograms and to characterize the fractal geometry of benign and malignant MC clusters. This was done in the context of a preliminary analysis of a small dataset, via a novel way to partition the wavelet-transform space-scale skeleton. For the first time, the estimated 3D fractal structure of a breast lesion was inferred by pairing the information from two separate 2D projected mammographic views of the same breast, i.e. the cranial-caudal (CC) and mediolateral-oblique (MLO) views. As a novelty, we define the "CC-MLO fractal dimension plot", where a "fractal zone" and "Euclidean zones" (non-fractal) are defined. 118 images (59 cases, 25 malignant and 34 benign) obtained from a digital databank of mammograms with known radiologist diagnostics were analyzed to determine which cases would be plotted in the fractal zone and which cases would fall in the Euclidean zones. 92% of malignant breast lesions studied (23 out of 25 cases) were in the fractal zone while 88% of the benign lesions were in the Euclidean zones (30 out of 34 cases). Furthermore, a Bayesian statistical analysis shows that, with 95% credibility, the probability that fractal breast lesions are malignant is between 74% and 98%. Alternatively, with 95% credibility, the probability that Euclidean breast lesions are benign is between 76% and 96%. These results support the notion that the fractal structure of malignant tumors is more likely to be associated with an invasive behavior into the surrounding tissue compared to the less invasive, Euclidean structure of benign tumors. Finally, based on indirect 3D reconstructions from the 2D views, we conjecture that all breast tumors considered in this study, benign and malignant, fractal or Euclidean, restrict their growth to 2-dimensional manifolds within the breast tissue.

  20. The effect of a compression paddle on energy response, calibration and measurement with mammographic dosimeters using ionization chambers and solid-state detectors.

    PubMed

    Hourdakis, C J; Boziari, A; Koumbouli, E

    2009-02-21

    A compression paddle is always used in mammography x-ray examinations, in order to improve image quality and reduce patient doses. Although clinical dose measurements should be performed with the paddle to interfere with the x-ray beam, calibration of mammography dosimeters is performed free in air without the presence of the paddle. The paddle hardens the x-ray beam, which has an impact on a dosimeter performance, particularly on high-energy-dependent detectors. Due to the paddle, clinical mammography x-ray systems may exhibit beams with HVL values exceeding those of the IEC 61267 RQR-M series qualities at which dosimeters are usually calibrated. In this study, the influence of the paddle in mammography dosimetry is examined, in Mo/Mo anode/filter x-ray qualities. PMMA slabs of 1, 2 and 3 mm thickness and Al foils of 0.05, 0.10 and 0.15 mm thicknesses were used to simulate the paddles, producing beams with HVL values from 0.28 up to 0.43 mmAl. In these qualities, four solid-state (ST) detectors and three ionizations chambers (IC) were calibrated in terms of Kair and N(K) and k(Q) were deduced. The results showed that all IC and two modern-type ST dosimeters have a flat energy response in the above HVL range (less than 3%), so their calibration factor at RQR-M2 quality could be safely used for clinical measurements. Two other ST dosimeters exhibit up to 20% energy response, so differences up to 15% in dose measurement may be observed if the effect of paddle on their performance is ignored. Finally, the need of additional mammographic calibration qualities to the existing IEC 61267 RQR-M series is examined and discussed.

  1. In newly diagnosed breast cancer, screening MRI of the contralateral breast detects mammographically occult cancer, even in elderly women: the mayo clinic in Florida experience.

    PubMed

    Bernard, Johnny Ray; Vallow, Laura A; DePeri, Elizabeth R; McNeil, Rebecca B; Feigel, Deborah G; Amar, Surabhi; Buskirk, Steven J; Perez, Edith A

    2010-01-01

    The role of magnetic resonance imaging (MRI) in patients with newly diagnosed breast cancer is somewhat controversial. The purpose of this study was to evaluate the prevalence of synchronous, occult contralateral breast cancer detected by MRI but not by mammography or clinical breast examination in women with newly diagnosed breast cancer, including those aged 70 years or older at our institution. MRI results for women with newly diagnosed breast cancer who underwent bilateral breast MRI after negative mammography and clinical examination between February 2003 and November 2007 at Mayo Clinic in Florida were reviewed. The prevalence of pathologically confirmed contralateral carcinoma diagnosed solely by MRI was determined and analyzed in the context of age, family history, menopausal status, breast density, and primary-tumor characteristics. Logistic regression was used to explore the association between contralateral carcinoma and potential patient risk factors. A total of 425 women were evaluated, of whom 129 (30%) were aged 70 years or older. A contralateral biopsy was recommended and performed solely on the basis of MRI in 72 of the 425 women (17%). Sixteen of these 72 women (22%) had pathologically confirmed carcinoma, including seven in the older subgroup. The prevalence of clinically and mammographically occult contralateral carcinoma detected by MRI was 3.8% (16/425) overall and 5.4% (7/129) in the group of older women. When potential risk factors for contralateral breast cancer were evaluated, postmenopausal status was the only significant predictor of contralateral cancer detected by MRI (p = 0.016). We concluded that contralateral breast screening with MRI should be considered in postmenopausal women with newly diagnosed breast cancer, even those aged 70 years or older at diagnosis.

  2. Effects of Tamoxifen and oestrogen on histology and radiographic density in high and low mammographic density human breast tissues maintained in murine tissue engineering chambers.

    PubMed

    Chew, G L; Huo, C W; Huang, D; Blick, T; Hill, P; Cawson, J; Frazer, H; Southey, M C; Hopper, J L; Britt, K; Henderson, M A; Haviv, I; Thompson, E W

    2014-11-01

    Mammographic density (MD) is a strong risk factor for breast cancer. It is altered by exogenous endocrine treatments, including hormone replacement therapy and Tamoxifen. Such agents also modify breast cancer (BC) risk. However, the biomolecular basis of how systemic endocrine therapy modifies MD and MD-associated BC risk is poorly understood. This study aims to determine whether our xenograft biochamber model can be used to study the effectiveness of therapies aimed at modulating MD, by examine the effects of Tamoxifen and oestrogen on histologic and radiographic changes in high and low MD tissues maintained within the biochamber model. High and low MD human tissues were precisely sampled under radiographic guidance from prophylactic mastectomy fresh specimens of high-risk women, then inserted into separate vascularized murine biochambers. The murine hosts were concurrently implanted with Tamoxifen, oestrogen or placebo pellets, and the high and low MD biochamber tissues maintained in the murine host environment for 3 months, before the high and low MD biochamber tissues were harvested for histologic and radiographic analyses. The radiographic density of high MD tissue maintained in murine biochambers was decreased in Tamoxifen-treated mice compared to oestrogen-treated mice (p = 0.02). Tamoxifen treatment of high MD tissue in SCID mice led to a decrease in stromal (p = 0.009), and an increase in adipose (p = 0.023) percent areas, compared to placebo-treated mice. No histologic or radiographic differences were observed in low MD biochamber tissue with any treatment. High MD biochamber tissues maintained in mice implanted with Tamoxifen, oestrogen or placebo pellets had dynamic and measurable histologic compositional and radiographic changes. This further validates the dynamic nature of the MD xenograft model, and suggests the biochamber model may be useful for assessing the underlying molecular pathways of Tamoxifen-reduced MD, and in testing of other

  3. High Mammographic Breast Density Is Independent Predictor of Local But Not Distant Recurrence After Lumpectomy and Radiotherapy for Invasive Breast Cancer

    SciTech Connect

    Park, Catherine C. Rembert, James; Chew, Karen; Moore, Dan; Kerlikowske, Karla

    2009-01-01

    Purpose: Biologically meaningful predictors for locoregional recurrence (LRR) in patients undergoing breast-conserving surgery (BCS) and radiotherapy (RT) are lacking. Tissue components, including extracellular matrix, could confer resistance to ionizing radiation. Fibroglandular and extracellular matrix components of breast tissue relative to adipose tissue can be quantified by the mammographic breast density (MBD), the proportion of dense area relative to the total breast area on mammography. We hypothesized that the MBD might be a predictor of LRR after BCS and RT for invasive breast cancer. Methods and Materials: We conducted a nested case-control study of 136 women with invasive breast cancer who had undergone BCS and RT and had had the MBD ascertained before, or at, diagnosis. Women with known recurrence were matched to women without recurrence by year of diagnosis. The median follow-up was 7.7 years. The percentage of MBD was measured using a computer-based threshold method. Results: Patients with a high MBD ({>=}75% density) vs. low ({<=}25%) were at increased risk of LRR (hazard ratio, 4.30; 95% confidence interval, 0.88-021.0; p = 0.071) but not distant recurrence. In addition, we found a complete inverse correlation between high MBD and obesity (body mass index, {>=}30 kg/m{sup 2}). In a multivariate Cox proportional hazards model, patients with MBD in the greatest quartile were at significantly greater risk of LRR (hazard ratio, 6.6; 95% confidence interval, 1.6-27.7; p = 0.01). Obesity without a high MBD also independently predicted for LRR (hazard ratio, 19.3; 95% confidence interval, 4.5-81.7; p < 0.001). Conclusion: The results of our study have shown that a high MBD and obesity are significant independent predictors of LRR after BCS and RT for invasive breast cancer. Additional studies are warranted to validate these findings.

  4. Benign-malignant mass classification in mammogram using edge weighted local texture features

    NASA Astrophysics Data System (ADS)

    Rabidas, Rinku; Midya, Abhishek; Sadhu, Anup; Chakraborty, Jayasree

    2016-03-01

    This paper introduces novel Discriminative Robust Local Binary Pattern (DRLBP) and Discriminative Robust Local Ternary Pattern (DRLTP) for the classification of mammographic masses as benign or malignant. Mass is one of the common, however, challenging evidence of breast cancer in mammography and diagnosis of masses is a difficult task. Since DRLBP and DRLTP overcome the drawbacks of Local Binary Pattern (LBP) and Local Ternary Pattern (LTP) by discriminating a brighter object against the dark background and vice-versa, in addition to the preservation of the edge information along with the texture information, several edge-preserving texture features are extracted, in this study, from DRLBP and DRLTP. Finally, a Fisher Linear Discriminant Analysis method is incorporated with discriminating features, selected by stepwise logistic regression method, for the classification of benign and malignant masses. The performance characteristics of DRLBP and DRLTP features are evaluated using a ten-fold cross-validation technique with 58 masses from the mini-MIAS database, and the best result is observed with DRLBP having an area under the receiver operating characteristic curve of 0.982.

  5. Using Qualitative Research Methods in Higher Education

    ERIC Educational Resources Information Center

    Savenye, Wilhelmina C.; Robinson, Rhonda S.

    2005-01-01

    Researchers investigating issues related to computing in higher education are increasingly using qualitative research methods to conduct their investigations. However, they may have little training or experience in qualitative research. The purpose of this paper is to introduce researchers to the appropriate use of qualitative methods. It begins…

  6. A General Survey of Qualitative Research Methodology.

    ERIC Educational Resources Information Center

    Cary, Rick

    Current definitions and philosophical foundations of qualitative research are presented; and designs, evaluation methods, and issues in application of qualitative research to education are discussed. The effects of positivism and the post-positivist era on qualitative research are outlined, and naturalist and positivist approaches are contrasted.…

  7. Quantifying Qualitative Data Using Cognitive Maps

    ERIC Educational Resources Information Center

    Scherp, Hans-Ake

    2013-01-01

    The aim of the article is to show how substantial qualitative material consisting of graphic cognitive maps can be analysed by using digital CmapTools, Excel and SPSS. Evidence is provided of how qualitative and quantitative methods can be combined in educational research by transforming qualitative data into quantitative data to facilitate…

  8. Strategies of Qualitative Inquiry. Third Edition

    ERIC Educational Resources Information Center

    Denzin, Norman K., Ed.; Lincoln, Yvonna S., Ed.

    2007-01-01

    "Strategies of Qualitative Inquiry, Third Edition," the second volume in the paperback version of "The SAGE Handbook of Qualitative Research, 3rd Edition," consists of Part III of the handbook ("Strategies of Inquiry"). "Strategies of Qualitative Inquiry, Third Edition" presents the major tactics--historically, the research methods--that…

  9. Understanding and critiquing qualitative research papers.

    PubMed

    Lee, Polly

    This article, the last in a series on research, examines the steps involved in qualitative research before introducing more terminology regarding the different approaches to qualitative studies. The process of evaluating qualitative research is explored by using an evaluative framework to further explain some of the terminology that researchers use.

  10. Teaching Qualitative Research to Practitioner-Researchers

    ERIC Educational Resources Information Center

    Cox, Rebecca D.

    2012-01-01

    Practitioner-researchers are well-positioned to apply qualitative methods to the study of significant problems of educational practice. However, while learning the skills of qualitative inquiry, practitioners may be compelled by forces outside of qualitative research classrooms to think quantitatively. In this article, the author considers two…

  11. Publishing Qualitative Research in Counseling Journals

    ERIC Educational Resources Information Center

    Hunt, Brandon

    2011-01-01

    This article focuses on the essential elements to be included when developing a qualitative study and preparing the findings for publication. Using the sections typically found in a qualitative article, the author describes content relevant to each section, with additional suggestions for publishing qualitative research.

  12. Infusing Qualitative Traditions in Counseling Research Designs

    ERIC Educational Resources Information Center

    Hays, Danica G.; Wood, Chris

    2011-01-01

    Research traditions serve as a blueprint or guide for a variety of design decisions throughout qualitative inquiry. This article presents 6 qualitative research traditions: grounded theory, phenomenology, consensual qualitative research, ethnography, narratology, and participatory action research. For each tradition, the authors describe its…

  13. Qualitative Research--Another Way of Knowing.

    ERIC Educational Resources Information Center

    Rogers, Vincent R.

    Qualitative research is based on the direct observation of human activity and interaction in an ongoing, naturalistic fashion. Qualitative researchers are concerned with the internal life of schools; what is really occurring in classrooms, corridors, cafeterias, and playgrounds. Qualitative researchers look at what people ordinarily take for…

  14. A qualitative evidence synthesis on the management of male obesity

    PubMed Central

    Archibald, Daryll; Douglas, Flora; Hoddinott, Pat; van Teijlingen, Edwin; Stewart, Fiona; Robertson, Clare; Boyers, Dwayne; Avenell, Alison

    2015-01-01

    Objectives To investigate what weight management interventions work for men, with which men, and under what circumstances. Design Realist synthesis of qualitative studies. Data sources Sensitive searches of 11 electronic databases from 1990 to 2012 supplemented by grey literature searches. Study selection Studies published between 1990 and 2012 reporting qualitative research with obese men, or obese men in contrast to obese women and lifestyle or drug weight management were included. The studies included men aged 16 years or over, with no upper age limit, with a mean or median body mass index of 30 kg/m2 in all settings. Results 22 studies were identified, including 5 qualitative studies linked to randomised controlled trials of weight maintenance interventions and 8 qualitative studies linked to non-randomised intervention studies, and 9 relevant UK-based qualitative studies not linked to any intervention. Health concerns and the perception that certain programmes had ‘worked’ for other men were the key factors that motivated men to engage with weight management programmes. Barriers to engagement and adherence with programmes included: men not problematising their weight until labelled ‘obese’; a lack of support for new food choices by friends and family, and reluctance to undertake extreme dieting. Retaining some autonomy over what is eaten; flexibility about treats and alcohol, and a focus on physical activity were attractive features of programmes. Group interventions, humour and social support facilitated attendance and adherence. Men were motivated to attend programmes in settings that were convenient, non-threatening and congruent with their masculine identities, but men were seldom involved in programme design. Conclusions Men's perspectives and preferences within the wider context of family, work and pleasure should be sought when designing weight management services. Qualitative research is needed with men to inform all aspects of intervention

  15. The Utility of Template Analysis in Qualitative Psychology Research.

    PubMed

    Brooks, Joanna; McCluskey, Serena; Turley, Emma; King, Nigel

    2015-04-03

    Thematic analysis is widely used in qualitative psychology research, and in this article, we present a particular style of thematic analysis known as Template Analysis. We outline the technique and consider its epistemological position, then describe three case studies of research projects which employed Template Analysis to illustrate the diverse ways it can be used. Our first case study illustrates how the technique was employed in data analysis undertaken by a team of researchers in a large-scale qualitative research project. Our second example demonstrates how a qualitative study that set out to build on mainstream theory made use of the a priori themes (themes determined in advance of coding) permitted in Template Analysis. Our final case study shows how Template Analysis can be used from an interpretative phenomenological stance. We highlight the distinctive features of this style of thematic analysis, discuss the kind of research where it may be particularly appropriate, and consider possible limitations of the technique. We conclude that Template Analysis is a flexible form of thematic analysis with real utility in qualitative psychology research.

  16. The Utility of Template Analysis in Qualitative Psychology Research

    PubMed Central

    Brooks, Joanna; McCluskey, Serena; Turley, Emma; King, Nigel

    2015-01-01

    Thematic analysis is widely used in qualitative psychology research, and in this article, we present a particular style of thematic analysis known as Template Analysis. We outline the technique and consider its epistemological position, then describe three case studies of research projects which employed Template Analysis to illustrate the diverse ways it can be used. Our first case study illustrates how the technique was employed in data analysis undertaken by a team of researchers in a large-scale qualitative research project. Our second example demonstrates how a qualitative study that set out to build on mainstream theory made use of the a priori themes (themes determined in advance of coding) permitted in Template Analysis. Our final case study shows how Template Analysis can be used from an interpretative phenomenological stance. We highlight the distinctive features of this style of thematic analysis, discuss the kind of research where it may be particularly appropriate, and consider possible limitations of the technique. We conclude that Template Analysis is a flexible form of thematic analysis with real utility in qualitative psychology research. PMID:27499705

  17. Data analysis in qualitative research: a brief guide to using nvivo.

    PubMed

    Wong, Lp

    2008-01-01

    Qualitative data is often subjective, rich, and consists of in-depth information normally presented in the form of words. Analysing qualitative data entails reading a large amount of transcripts looking for similarities or differences, and subsequently finding themes and developing categories. Traditionally, researchers 'cut and paste' and use coloured pens to categorise data. Recently, the use of software specifically designed for qualitative data management greatly reduces technical sophistication and eases the laborious task, thus making the process relatively easier. A number of computer software packages has been developed to mechanise this 'coding' process as well as to search and retrieve data. This paper illustrates the ways in which NVivo can be used in the qualitative data analysis process. The basic features and primary tools of NVivo which assist qualitative researchers in managing and analysing their data are described.

  18. QML-AiNet: An immune network approach to learning qualitative differential equation models.

    PubMed

    Pang, Wei; Coghill, George M

    2015-02-01

    In this paper, we explore the application of Opt-AiNet, an immune network approach for search and optimisation problems, to learning qualitative models in the form of qualitative differential equations. The Opt-AiNet algorithm is adapted to qualitative model learning problems, resulting in the proposed system QML-AiNet. The potential of QML-AiNet to address the scalability and multimodal search space issues of qualitative model learning has been investigated. More importantly, to further improve the efficiency of QML-AiNet, we also modify the mutation operator according to the features of discrete qualitative model space. Experimental results show that the performance of QML-AiNet is comparable to QML-CLONALG, a QML system using the clonal selection algorithm (CLONALG). More importantly, QML-AiNet with the modified mutation operator can significantly improve the scalability of QML and is much more efficient than QML-CLONALG.

  19. QML-AiNet: An immune network approach to learning qualitative differential equation models

    PubMed Central

    Pang, Wei; Coghill, George M.

    2015-01-01

    In this paper, we explore the application of Opt-AiNet, an immune network approach for search and optimisation problems, to learning qualitative models in the form of qualitative differential equations. The Opt-AiNet algorithm is adapted to qualitative model learning problems, resulting in the proposed system QML-AiNet. The potential of QML-AiNet to address the scalability and multimodal search space issues of qualitative model learning has been investigated. More importantly, to further improve the efficiency of QML-AiNet, we also modify the mutation operator according to the features of discrete qualitative model space. Experimental results show that the performance of QML-AiNet is comparable to QML-CLONALG, a QML system using the clonal selection algorithm (CLONALG). More importantly, QML-AiNet with the modified mutation operator can significantly improve the scalability of QML and is much more efficient than QML-CLONALG. PMID:25648212

  20. Designing using manufacturing features

    NASA Astrophysics Data System (ADS)

    Szecsi, T.; Hoque, A. S. M.

    2012-04-01

    This paper presents a design system that enables the composition of a part using manufacturing features. Features are selected from feature libraries. Upon insertion, the system ensures that the feature does not contradict the design-for-manufacture rules. This helps eliminating costly manufacturing problems. The system is developed as an extension to a commercial CAD/CAM system Pro/Engineer.

  1. System monitoring and diagnosis with qualitative models

    NASA Technical Reports Server (NTRS)

    Kuipers, Benjamin

    1991-01-01

    A substantial foundation of tools for model-based reasoning with incomplete knowledge was developed: QSIM (a qualitative simulation program) and its extensions for qualitative simulation; Q2, Q3 and their successors for quantitative reasoning on a qualitative framework; and the CC (component-connection) and QPC (Qualitative Process Theory) model compilers for building QSIM QDE (qualitative differential equation) models starting from different ontological assumptions. Other model-compilers for QDE's, e.g., using bond graphs or compartmental models, have been developed elsewhere. These model-building tools will support automatic construction of qualitative models from physical specifications, and further research into selection of appropriate modeling viewpoints. For monitoring and diagnosis, plausible hypotheses are unified against observations to strengthen or refute the predicted behaviors. In MIMIC (Model Integration via Mesh Interpolation Coefficients), multiple hypothesized models of the system are tracked in parallel in order to reduce the 'missing model' problem. Each model begins as a qualitative model, and is unified with a priori quantitative knowledge and with the stream of incoming observational data. When the model/data unification yields a contradiction, the model is refuted. When there is no contradiction, the predictions of the model are progressively strengthened, for use in procedure planning and differential diagnosis. Only under a qualitative level of description can a finite set of models guarantee the complete coverage necessary for this performance. The results of this research are presented in several publications. Abstracts of these published papers are presented along with abtracts of papers representing work that was synergistic with the NASA grant but funded otherwise. These 28 papers include but are not limited to: 'Combined qualitative and numerical simulation with Q3'; 'Comparative analysis and qualitative integral representations

  2. AI/OR computational model for integrating qualitative and quantitative design methods

    NASA Technical Reports Server (NTRS)

    Agogino, Alice M.; Bradley, Stephen R.; Cagan, Jonathan; Jain, Pramod; Michelena, Nestor

    1990-01-01

    A theoretical framework for integrating qualitative and numerical computational methods for optimally-directed design is described. The theory is presented as a computational model and features of implementations are summarized where appropriate. To demonstrate the versatility of the methodology we focus on four seemingly disparate aspects of the design process and their interaction: (1) conceptual design, (2) qualitative optimal design, (3) design innovation, and (4) numerical global optimization.

  3. Qualitative Analysis for Maintenance Process Assessment

    NASA Technical Reports Server (NTRS)

    Brand, Lionel; Kim, Yong-Mi; Melo, Walcelio; Seaman, Carolyn; Basili, Victor

    1996-01-01

    In order to improve software maintenance processes, we first need to be able to characterize and assess them. These tasks must be performed in depth and with objectivity since the problems are complex. One approach is to set up a measurement-based software process improvement program specifically aimed at maintenance. However, establishing a measurement program requires that one understands the problems to be addressed by the measurement program and is able to characterize the maintenance environment and processes in order to collect suitable and cost-effective data. Also, enacting such a program and getting usable data sets takes time. A short term substitute is therefore needed. We propose in this paper a characterization process aimed specifically at maintenance and based on a general qualitative analysis methodology. This process is rigorously defined in order to be repeatable and usable by people who are not acquainted with such analysis procedures. A basic feature of our approach is that actual implemented software changes are analyzed in order to understand the flaws in the maintenance process. Guidelines are provided and a case study is shown that demonstrates the usefulness of the approach.

  4. Qualitative research methods for medical educators.

    PubMed

    Hanson, Janice L; Balmer, Dorene F; Giardino, Angelo P

    2011-01-01

    This paper provides a primer for qualitative research in medical education. Our aim is to equip readers with a basic understanding of qualitative research and prepare them to judge the goodness of fit between qualitative research and their own research questions. We provide an overview of the reasons for choosing a qualitative research approach and potential benefits of using these methods for systematic investigation. We discuss developing qualitative research questions, grounding research in a philosophical framework, and applying rigorous methods of data collection, sampling, and analysis. We also address methods to establish the trustworthiness of a qualitative study and introduce the reader to ethical concerns that warrant special attention when planning qualitative research. We conclude with a worksheet that readers may use for designing a qualitative study. Medical educators ask many questions that carefully designed qualitative research would address effectively. Careful attention to the design of qualitative studies will help to ensure credible answers that will illuminate many of the issues, challenges, and quandaries that arise while doing the work of medical education.

  5. Breastfeeding Twins: A Qualitative Study

    PubMed Central

    Alvur, Tuncay Muge; Kose, Dilek; Nemut, Tijen

    2013-01-01

    The purpose of this qualitative research was to explore the needs and difficulties of mothers who had multiple babies at Sakarya County by focusing on their breastfeeding experience. Ten mothers who gave birth to multiple infants participated in the study voluntarily. The framework method of data analysis was applied systematically both within and across cases, with categories and themes identified by reading transcripts of interviews. Major themes generated from focus narrative interviews are described. These themes are: willingness of mothers to breastfeed and continue, management of breastfeeding, use of pacifier, daily life, ınstructions of healthcare personnel, and advices from practice of experienced mothers. This study showed that women were aware of the importance of mother's milk for their babies. They all, somehow, made intensive efforts to breastfeed their twins. Women who expect and/or have multiple babies need much more support and guidance, which may include advice for nutritional and daily care. PMID:24592592

  6. QUALITATIVE INTERPRETATION OF GALAXY SPECTRA

    SciTech Connect

    Sanchez Almeida, J.; Morales-Luis, A. B.; Terlevich, R.; Terlevich, E.; Cid Fernandes, R. E-mail: abml@iac.es E-mail: eterlevi@inaoep.mx

    2012-09-10

    We describe a simple step-by-step guide to qualitative interpretation of galaxy spectra. Rather than an alternative to existing automated tools, it is put forward as an instrument for quick-look analysis and for gaining physical insight when interpreting the outputs provided by automated tools. Though the recipe is for general application, it was developed for understanding the nature of the Automatic Spectroscopic K-means-based (ASK) template spectra. They resulted from the classification of all the galaxy spectra in the Sloan Digital Sky Survey data release 7, thus being a comprehensive representation of the galaxy spectra in the local universe. Using the recipe, we give a description of the properties of the gas and the stars that characterize the ASK classes, from those corresponding to passively evolving galaxies, to H II galaxies undergoing a galaxy-wide starburst. The qualitative analysis is found to be in excellent agreement with quantitative analyses of the same spectra. We compare the mean ages of the stellar populations with those inferred using the code STARLIGHT. We also examine the estimated gas-phase metallicity with the metallicities obtained using electron-temperature-based methods. A number of byproducts follow from the analysis. There is a tight correlation between the age of the stellar population and the metallicity of the gas, which is stronger than the correlations between galaxy mass and stellar age, and galaxy mass and gas metallicity. The galaxy spectra are known to follow a one-dimensional sequence, and we identify the luminosity-weighted mean stellar age as the affine parameter that describes the sequence. All ASK classes happen to have a significant fraction of old stars, although spectrum-wise they are outshined by the youngest populations. Old stars are metal-rich or metal-poor depending on whether they reside in passive galaxies or in star-forming galaxies.

  7. Qualitative map learning based on covisibility of objects.

    PubMed

    Yairi, Takehisa; Hori, Koichi; Hirama, Kosuke

    2005-08-01

    Autonomous map construction is one of the most fundamental and significant issues in intelligent mobile robot research. While a variety of map construction methods have been proposed, most require some quantitative measurements of the environment and a mechanism of precise self-localization. This paper proposes a novel map construction method using only qualitative information about "how often two objects are observed simultaneously." This method is based on heuristics--"closely located objects are likely to be seen simultaneously more often than distant objects" and a well-known multivariate data analysis technique-multidimensional scaling. A significant feature of this method is that it requires neither quantitative sensor measurements nor information about the robot's own position. Simulation and experimental results demonstrated that this method is sufficiently practical for capturing a qualitative spatial relationship among identifiable landmark objects rapidly.

  8. Early detection of breast cancer through population-based mammographic screening in Asian women: a comparison study between screen-detected and symptomatic breast cancers.

    PubMed

    Chuwa, Esther W L; Yeo, Allen W Y; Koong, Heng Nung; Wong, Chow Yin; Yong, Wei Sean; Tan, Puay Hoon; Ho, Juliana T S; Wong, Jill S L; Ho, Gay Hui

    2009-01-01

    The first nation-wide mammographic screening program in Asia, BreastScreen Singapore (BSS), was launched in Singapore in January 2002. This study compared the presentation and results of screen-detected breast cancers with symptomatic breast cancers in two affiliated high-volume institutions, one of which was an assessment centre for BSS. The medical records of patients diagnosed with primary breast cancer at the Department of General Surgery, Singapore General Hospital and the Department of Surgical Oncology, National Cancer Centre, Singapore, during the period January 2002 to December 2003 were reviewed. Clinical and pathological comparisons were made between screen-detected lesions and symptomatic lesions. Of a total of 767 cases, 640 (83.4%) were invasive carcinomas and 127 (16.6%) were ductal carcinoma in-situ (DCIS) lesions. Only 13.4% of them were screen-detected. Compared to symptomatic cancers, screen-detected lesions were of smaller size (median size 18 versus 23 mm), a lower stage (stages 0-2, 95 versus 83.2%) and histologic grade (grade 1-2, 71 versus 60%), with a higher incidence of DCIS (31.0 versus 14.3%) and had higher rates of breast conservation (45.6 versus 28.2%) (all p-values <0.05). By multivariate analysis, tumor palpability, tumor size >20 mm, nodal involvement, cerbB2 overexpression, and advanced disease stage were independent poor prognostic factors for disease-free survival, whereas nodal involvement, advanced disease, and recurrence predicted poor cancer-specific survival. However, there was no statistically significant difference in disease-free survival or cancer-specific survival between the two groups at a median follow-up of 38 months. Screening mammography has allowed the detection of smaller and hence oncologically more favorable lesions in Asian women. Although no significant survival benefit was demonstrated in our study, a longer period of follow-up is essential before the benefit of mortality reduction, as a result of

  9. Dynamic changes in high and low mammographic density human breast tissues maintained in murine tissue engineering chambers during various murine peripartum states and over time.

    PubMed

    Chew, G L; Huang, D; Huo, C W; Blick, T; Hill, P; Cawson, J; Frazer, H; Southey, M D; Hopper, J L; Henderson, M A; Haviv, I; Thompson, E W

    2013-07-01

    Mammographic density (MD) is a strong heritable risk factor for breast cancer, and may decrease with increasing parity. However, the biomolecular basis for MD-associated breast cancer remains unclear, and systemic hormonal effects on MD-associated risk is poorly understood. This study assessed the effect of murine peripartum states on high and low MD tissue maintained in a xenograft model of human MD. Method High and low MD human breast tissues were precisely sampled under radiographic guidance from prophylactic mastectomy specimens of women. The high and low MD tissues were maintained in separate vascularised biochambers in nulliparous or pregnant SCID mice for 4 weeks, or mice undergoing postpartum involution or lactation for three additional weeks. High and low MD biochamber material was harvested for histologic and radiographic comparisons during various murine peripartum states. High and low MD biochamber tissues in nulliparous mice were harvested at different timepoints for histologic and radiographic comparisons. Results High MD biochamber tissues had decreased stromal (p = 0.0027), increased adipose (p = 0.0003) and a trend to increased glandular tissue areas (p = 0.076) after murine postpartum involution. Stromal areas decreased (p = 0.042), while glandular (p = 0.001) and adipose areas (p = 0.009) increased in high MD biochamber tissues during lactation. A difference in radiographic density was observed in high (p = 0.0021) or low MD biochamber tissues (p = 0.004) between nulliparous, pregnant and involution groups. No differences in tissue composition were observed in high or low MD biochamber tissues maintained for different durations, although radiographic density increased over time. Conclusion High MD biochamber tissues had measurable histologic changes after postpartum involution or lactation. Alterations in radiographic density occurred in biochamber tissues between different peripartum states and over time. These findings

  10. The use of saturation in qualitative research.

    PubMed

    Walker, Janiece L

    2012-01-01

    Understanding qualitative research is an important component of cardiovascular nurses' practice and allows them to understand the experiences, stories, and perceptions of patients with cardiovascular conditions. In understanding qualitative research methods, it is essential that the cardiovascular nurse understands the process of saturation within qualitative methods. Saturation is a tool used for ensuring that adequate and quality data are collected to support the study. Saturation is frequently reported in qualitative research and may be the gold standard. However, the use of saturation within methods has varied. Hence, the purpose of this column is to provide insight for the cardiovascular nurse regarding the use of saturation by reviewing the recommendations for which qualitative research methods it is appropriate to use and how to know when saturation is achieved. In understanding saturation, the cardiovascular nurse can be a better consumer of qualitative research.

  11. When Assessment Data Are Words: Validity Evidence for Qualitative Educational Assessments.

    PubMed

    Cook, David A; Kuper, Ayelet; Hatala, Rose; Ginsburg, Shiphra

    2016-10-01

    Quantitative scores fail to capture all important features of learner performance. This awareness has led to increased use of qualitative data when assessing health professionals. Yet the use of qualitative assessments is hampered by incomplete understanding of their role in forming judgments, and lack of consensus in how to appraise the rigor of judgments therein derived. The authors articulate the role of qualitative assessment as part of a comprehensive program of assessment, and translate the concept of validity to apply to judgments arising from qualitative assessments. They first identify standards for rigor in qualitative research, and then use two contemporary assessment validity frameworks to reorganize these standards for application to qualitative assessment.Standards for rigor in qualitative research include responsiveness, reflexivity, purposive sampling, thick description, triangulation, transparency, and transferability. These standards can be reframed using Messick's five sources of validity evidence (content, response process, internal structure, relationships with other variables, and consequences) and Kane's four inferences in validation (scoring, generalization, extrapolation, and implications). Evidence can be collected and evaluated for each evidence source or inference. The authors illustrate this approach using published research on learning portfolios.The authors advocate a "methods-neutral" approach to assessment, in which a clearly stated purpose determines the nature of and approach to data collection and analysis. Increased use of qualitative assessments will necessitate more rigorous judgments of the defensibility (validity) of inferences and decisions. Evidence should be strategically sought to inform a coherent validity argument.

  12. A Qualitative Analysis of SAC Aircraft Maintenance.

    DTIC Science & Technology

    1982-09-01

    A122 815 A QUALITATIVE ANALYSIS OF SAC AIRCRAFT MRINTENANCE(U) 112 AIR FORCE INST OF TECH WRIGHT-PRTTERSON AFB OH SCHOOL OF SYSTEMS AND LOGISTICS D...Wright-Patterson Air Force Base, Ohio ’ ; " ... ..... ... ... . .. .. A QUALITATIVE ANALYSIS OF SAC AIRCRAFT MAINTENANCE Douglas P. Cook, Captain... QUALITATIVE ANALYSIS OF SAC Master’s Thesis AIRCRAFT MAINTENANCE 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(q) S. CONTRACT OR GRANT NUMBER(a) Douglas

  13. Essential elements in a qualitative dissertation proposal.

    PubMed

    Swenson, M M

    1996-04-01

    This article clarifies the requirements of a qualitative research proposal, specifically a qualitative doctoral dissertation. The recommendations will be useful to graduate students and faculty members who are writing a qualitative proposal for the first time or who are critiquing one. A summary of assumptions of non-traditional research paradigms as they apply to inquiry design, a suggestion of the contents of the first three chapters of a qualitative dissertation (usually included in a dissertation proposal), and suggestions for ensuring rigor in the design and conduct of the dissertation research are included.

  14. [A call for qualitative research in Orthodontics].

    PubMed

    Yitschaky, O; Hofnung, T; Zini, A

    2015-01-01

    Qualitative research is an umbrella term for an array of attitudes and strategies for conducting inquiries that are aimed at discerning how human beings understand, experience, and interpret the social world. It is employed in many different academic disciplines most particularly in the social sciences and humanities, however recently more and more qualitative research is being conducted under the medical sciences including dentistry and orthodontics. This is due to its nature of in-depth investigation, which can provide answers to questions that cannot be satisfactorily answered using quantitative methods alone. The aims of this article are to discuss the characteristics of qualitative research, to review the orthodontic English literature, and to highlight the advantages of qualitative research in orthodontics. The literature review yielded several important conclusions regarding qualitative research in orthodontics: 1. most of the qualitative research done in orthodontics chose to use semi structured in-depth interviews for data collection; 2. qualitative research highlights aspects that are very important, and sometimes crucial to everyday practice and long term treatment; 3. there is a lack of qualitative studies in the field of orthodontics. Taking into account the nature of the orthodontic treatment, which is a prolonged one, demanding of a good orthodontist-patient rapport, and a wide perspective on behalf of the clinician, filling the gap in the discipline through conducting more qualitative studies aimed at understanding the point of view of the patient, as well as that of the clinician, may be beneficial for the improvement of the treatment.

  15. Rocket engine diagnostics using qualitative modeling techniques

    NASA Technical Reports Server (NTRS)

    Binder, Michael; Maul, William; Meyer, Claudia; Sovie, Amy

    1992-01-01

    Researchers at NASA Lewis Research Center are presently developing qualitative modeling techniques for automated rocket engine diagnostics. A qualitative model of a turbopump interpropellant seal system has been created. The qualitative model describes the effects of seal failures on the system steady-state behavior. This model is able to diagnose the failure of particular seals in the system based on anomalous temperature and pressure values. The anomalous values input to the qualitative model are generated using numerical simulations. Diagnostic test cases include both single and multiple seal failures.

  16. Rocket engine diagnostics using qualitative modeling techniques

    NASA Technical Reports Server (NTRS)

    Binder, Michael; Maul, William; Meyer, Claudia; Sovie, Amy

    1992-01-01

    Researchers at NASA Lewis Research Center are presently developing qualitative modeling techniques for automated rocket engine diagnostics. A qualitative model of a turbopump interpropellant seal system was created. The qualitative model describes the effects of seal failures on the system steady state behavior. This model is able to diagnose the failure of particular seals in the system based on anomalous temperature and pressure values. The anomalous values input to the qualitative model are generated using numerical simulations. Diagnostic test cases include both single and multiple seal failures.

  17. Qualitative versus quantitative methods in psychiatric research.

    PubMed

    Razafsha, Mahdi; Behforuzi, Hura; Azari, Hassan; Zhang, Zhiqun; Wang, Kevin K; Kobeissy, Firas H; Gold, Mark S

    2012-01-01

    Qualitative studies are gaining their credibility after a period of being misinterpreted as "not being quantitative." Qualitative method is a broad umbrella term for research methodologies that describe and explain individuals' experiences, behaviors, interactions, and social contexts. In-depth interview, focus groups, and participant observation are among the qualitative methods of inquiry commonly used in psychiatry. Researchers measure the frequency of occurring events using quantitative methods; however, qualitative methods provide a broader understanding and a more thorough reasoning behind the event. Hence, it is considered to be of special importance in psychiatry. Besides hypothesis generation in earlier phases of the research, qualitative methods can be employed in questionnaire design, diagnostic criteria establishment, feasibility studies, as well as studies of attitude and beliefs. Animal models are another area that qualitative methods can be employed, especially when naturalistic observation of animal behavior is important. However, since qualitative results can be researcher's own view, they need to be statistically confirmed, quantitative methods. The tendency to combine both qualitative and quantitative methods as complementary methods has emerged over recent years. By applying both methods of research, scientists can take advantage of interpretative characteristics of qualitative methods as well as experimental dimensions of quantitative methods.

  18. New directions in qualitative research in psychology.

    PubMed

    Demuth, Carolin

    2015-06-01

    Qualitative Research gains increasing popularity in the field of Psychology. With the renewed interest, there are, however, also some risks related to the overhomogenization and increasing standardization of qualitative methods. This special issue is dedicated to clarify some of the existing misconceptions of qualitative research and to discuss its potentials for the field of psychology in light of recent endeavors to overcome paradigmatic battles and a re-orientation to the specifities of psychology. The issue comprises a discussion from workshop on the future of qualitative research in psychology organized at Aalborg University, and several contributions that resulted from it.

  19. Clustering granulometric features

    NASA Astrophysics Data System (ADS)

    Brun, Marcel; Balagurunathan, Yoganand; Barrera, Junior; Dougherty, Edward R.

    2002-05-01

    Granulometric features have been widely used for classification, segmentation and recently in estimation of parameters in shape models. In this paper we study the inference of clustering based on granulometric features for a collection of structuring probes in the context of random models. We use random Boolean models to represent grains of different shapes and structure. It is known that granulometric features are excellent descriptors of shape and structure of grains. Inference based on clustering these features helps to analyze the consistency of these features and clustering algorithms. This greatly aids in classifier design and feature selection. Features and the order of their addition play a role in reducing the inference errors. We study four different types of feature addition methods and the effect of replication in reducing the inference errors.

  20. Experience of fibromyalgia. Qualitative study.

    PubMed Central

    Raymond, M. C.; Brown, J. B.

    2000-01-01

    OBJECTIVE: To explore illness experiences of patients diagnosed with fibromyalgia. DESIGN: Qualitative method of in-depth interviews. SETTING: Midsize city in Ontario. PARTICIPANTS: Seven patients diagnosed with fibromyalgia. METHOD: Seven in-depth interviews were conducted to explore the illness experience of patients diagnosed with fibromyalgia. All interviews were audiotaped and transcribed verbatim. All interview transcriptions were read independently by the researchers, who then compared and combined their analysis. Final analysis involved examining all interviews collectively, thus permitting relationships between and among central themes to emerge. The analysis strategy used a phenomenologic approach and occurred concurrently rather than sequentially. MAIN FINDINGS: Themes that emerged from the interpretive analysis depict patients' journeys along a continuum from experiencing symptoms, through seeking a diagnosis, to coping with the illness. Experiencing symptoms was composed of four subcategories: pain, a precipitating event, associated symptoms, and modulating factors. Seeking a diagnosis entailed frustration and social isolation. Confirmation of diagnosis brought relief as well as anxiety about the future. After diagnosis, several steps led to creation of adaptive coping strategies, which were influenced by several factors. CONCLUSION: Findings suggest that the conventional medical model fails to address the complex experience of fibromyalgia. Adopting a patient-centred approach is important for helping patients cope with this disease. PMID:10845136

  1. Qualitative Inquiry in an Age of Educationalese

    ERIC Educational Resources Information Center

    Fischman, Gustavo E.; Tefera, Adai A.

    2014-01-01

    In this introduction we reflect on two key questions that initiated this special issue on qualitative inquiry: What can qualitative researchers do to regain their post-paradigm-wars cache? How do we avoid distracting "science wars" in the future? We suggest that the strong tendency to narrow the research methods accepted as…

  2. Understanding Qualitative Research: A School Nurse Perspective

    ERIC Educational Resources Information Center

    Broussard, Lisa

    2006-01-01

    More school nurses are engaging in the generation of research, and their studies increasingly are using qualitative methods to describe various areas of practice. This article provides an overview of 4 major qualitative methods: ethnography, phenomenology, grounded theory, and historical research. Examples of school nursing research studies that…

  3. Qualitative Research Designs: Selection and Implementation

    ERIC Educational Resources Information Center

    Creswell, John W.; Hanson, William E.; Plano Clark, Vicki L.; Morales, Alejandro

    2007-01-01

    Counseling psychologists face many approaches from which to choose when they conduct a qualitative research study. This article focuses on the processes of selecting, contrasting, and implementing five different qualitative approaches. Based on an extended example related to test interpretation by counselors, clients, and communities, this article…

  4. The Question of Quality in Qualitative Research.

    ERIC Educational Resources Information Center

    Locke, Lawrence F.

    Qualitative research is a model for systematic, data-based inquiry. It has been used widely in the social sciences, and it has a growing acceptance in educational research. Its purpose is to describe and understand a particular, bounded social setting. The differences between quantitative and qualitative research involve the methods employed at…

  5. Dewey's Qualitative Thought as Exemplary Art Education.

    ERIC Educational Resources Information Center

    Brigham, Don L.

    1989-01-01

    Examines John Dewey's theory of the qualitative mind, showing how his thought illuminates the process of artistic creation. Exemplifies Dewey's theory by referring to the documented creative processes of master artists, Picasso, Moore, Giacometti, and Cezanne. Identifies attributes of the qualitative thinker and artist, and presents educational…

  6. Validity in Qualitative Research: Application of Safeguards

    ERIC Educational Resources Information Center

    Daytner, Katrina M.

    2006-01-01

    The construct of validity has received considerable attention in qualitative methods literature (Denzin, 1989; Erickson, 1986; Geertz, 1973; Goetz & LeCompte, 1984; Howe & Eisenhart, 1990; Maxwell, 1992; Smith & Glass, 1987). Much of the attention has been focused upon the issue of whether qualitative results and interpretations accurately reflect…

  7. Integrating Qualitative and Quantitative Research in Organizations.

    DTIC Science & Technology

    1981-07-01

    phenomenological approaches at the subjective end of the continuum. A few researchers have suggested ways in which quantitative and qualitative methods may be...Lofland, lq76), symbolic interactionism (Blumer, 1969), ethnomethodology (Turner, 1974), existentialism (Douglas & Johnson, 1977), and phenomenology ...orienting perspectives. Although most qualitative research will use some form of participant observation, those taking a phenomenological approach which

  8. The Landscape of Qualitative Research. Third Edition

    ERIC Educational Resources Information Center

    Denzin, Norman K., Ed.; Lincoln, Yvonna, Ed.

    2007-01-01

    This book, the first volume of the paperback versions of the "The SAGE Handbook of Qualitative Research, Third Edition," takes a look at the field from a broadly theoretical perspective, and is composed of the Handbook's Parts I ("Locating the Field"), II ("Major Paradigms and Perspectives"), and VI ("The Future of Qualitative Research"). "The…

  9. Getting Specific about Qualitative Research Generalizability

    ERIC Educational Resources Information Center

    Chenail, Ronald J.

    2010-01-01

    The question of generalizability or the usefulness of qualitative research results beyond the confines of the primary site, sample, and study has been hotly debated by qualitative researchers for decades. When examining this question of generalization the first surprising finding is there appears to be no general consensus about the definition,…

  10. Qualitative Research in Counseling Psychology: Conceptual Foundations

    ERIC Educational Resources Information Center

    Morrow, Susan L.

    2007-01-01

    Beginning with calls for methodological diversity in counseling psychology, this article addresses the history and current state of qualitative research in counseling psychology. It identifies the historical and disciplinary origins as well as basic assumptions and underpinnings of qualitative research in general, as well as within counseling…

  11. Applying Knowledge of Qualitative Design and Analysis

    ERIC Educational Resources Information Center

    Baskas, Richard S.

    2011-01-01

    This study compared and contrasted two qualitative scholarly articles in relation to their research designs. Their designs were analyzed by the comparison of research references and research specific vocabulary to describe how various research methods were used. When researching and analyzing qualitative scholarly articles, it is imperative to…

  12. Computing in Qualitative Analysis: A Healthy Development?

    ERIC Educational Resources Information Center

    Richards, Lyn; Richards, Tom

    1991-01-01

    Discusses the potential impact of computers in qualitative health research. Describes the original goals, design, and implementation of NUDIST, a qualitative computing software. Argues for evaluation of the impact of computer techniques and for an opening of debate among program developers and users to address the purposes and power of computing…

  13. Qualitative-Based Methodology to Teaching Qualitative Methodology in Higher Education

    ERIC Educational Resources Information Center

    Katz, Sara

    2015-01-01

    There is no defined theory for teaching Qualitative Inquiry, and very few studies have focused on the topic. This study is a qualitative case study focused on the Qualitative Methods course that I teach at a college of education in Israel. The aim of the study is to explore and describe the course, to provide a true picture of my pedagogy, and to…

  14. Qualitative methods in environmental health research.

    PubMed Central

    Brown, Phil

    2003-01-01

    Public health researchers increasingly turn to qualitative methods either on their own or in combination with quantitative methods. Qualitative methods are especially important to community environmental health research, as they provide a way to produce community narratives that give voice to individuals and characterize the community in a full and complex fashion. This article first traces the legacy of qualitative research in environmental health, then uses a case study of the author's experiences studying the Woburn, Massachusetts, childhood leukemia cluster to provide personal and scholarly insights on qualitative approaches. That material then informs a discussion of important components of qualitative methods in environmental health research, including flexible study design, access, trust, empathy, and personal shifts in the researcher's worldview, bias, and the nature of the researcher's roles. A concluding discussion addresses issues in funding policy and research practices. PMID:14594634

  15. Qualitative data analysis: conceptual and practical considerations.

    PubMed

    Liamputtong, Pranee

    2009-08-01

    Qualitative inquiry requires that collected data is organised in a meaningful way, and this is referred to as data analysis. Through analytic processes, researchers turn what can be voluminous data into understandable and insightful analysis. This paper sets out the different approaches that qualitative researchers can use to make sense of their data including thematic analysis, narrative analysis, discourse analysis and semiotic analysis and discusses the ways that qualitative researchers can analyse their data. I first discuss salient issues in performing qualitative data analysis, and then proceed to provide some suggestions on different methods of data analysis in qualitative research. Finally, I provide some discussion on the use of computer-assisted data analysis.

  16. Quantitative and qualitative research: beyond the debate.

    PubMed

    Gelo, Omar; Braakmann, Diana; Benetka, Gerhard

    2008-09-01

    Psychology has been a highly quantitative field since its conception as a science. However, a qualitative approach to psychological research has gained increasing importance in the last decades, and an enduring debate between quantitative and qualitative approaches has arisen. The recently developed Mixed Methods Research (MMR) addresses this debate by aiming to integrate quantitative and qualitative approaches. This article outlines and discusses quantitative, qualitative and mixed methods research approaches with specific reference to their (1) philosophical foundations (i.e. basic sets of beliefs that ground inquiry), (2) methodological assumptions (i.e. principles and formal conditions which guide scientific investigation), and (3) research methods (i.e. concrete procedures for data collection, analysis and interpretation). We conclude that MMR may reasonably overcome the limitation of purely quantitative and purely qualitative approaches at each of these levels, providing a fruitful context for a more comprehensive psychological research.

  17. Integrating Quantitative Knowledge into a Qualitative Gene Regulatory Network

    PubMed Central

    Bourdon, Jérémie; Eveillard, Damien; Siegel, Anne

    2011-01-01

    Despite recent improvements in molecular techniques, biological knowledge remains incomplete. Any theorizing about living systems is therefore necessarily based on the use of heterogeneous and partial information. Much current research has focused successfully on the qualitative behaviors of macromolecular networks. Nonetheless, it is not capable of taking into account available quantitative information such as time-series protein concentration variations. The present work proposes a probabilistic modeling framework that integrates both kinds of information. Average case analysis methods are used in combination with Markov chains to link qualitative information about transcriptional regulations to quantitative information about protein concentrations. The approach is illustrated by modeling the carbon starvation response in Escherichia coli. It accurately predicts the quantitative time-series evolution of several protein concentrations using only knowledge of discrete gene interactions and a small number of quantitative observations on a single protein concentration. From this, the modeling technique also derives a ranking of interactions with respect to their importance during the experiment considered. Such a classification is confirmed by the literature. Therefore, our method is principally novel in that it allows (i) a hybrid model that integrates both qualitative discrete model and quantities to be built, even using a small amount of quantitative information, (ii) new quantitative predictions to be derived, (iii) the robustness and relevance of interactions with respect to phenotypic criteria to be precisely quantified, and (iv) the key features of the model to be extracted that can be used as a guidance to design future experiments. PMID:21935350

  18. Modern and Fossil Raindrop Impressions as a Lesson in Interpretation of Ancient Sedimentary Features.

    ERIC Educational Resources Information Center

    Pardi, Richard R.; Brickner, Dorene

    1990-01-01

    Procedures for duplicating fossil raindrop impressions are presented. The use of modern and fossil imprints as the basis for qualitative and quantitative lessons in the interpretation of ancient sedimentary features is discussed. (CW)

  19. Qualitative Reliability Issues for Solid and Liquid Wall Fusion Design

    SciTech Connect

    Cadwallader, Lee Charles

    2001-01-01

    This report is an initial effort to identify issues affecting reliability and availability of solid and liquid wall designs for magnetic fusion power plant designs. A qualitative approach has been used to identify the possible failure modes of major system components and their effects on the systems. A general set of design attributes known to affect the service reliability has been examined for the overview solid and liquid wall designs, and some specific features of good first wall design have been discussed and applied to these designs as well. The two generalized designs compare well in regard to these design attributes. The strengths and weaknesses of each design approach are seen in the comparison of specific features.

  20. Qualitative Reliability Issues for Solid and Liquid Wall Fusion Designs

    SciTech Connect

    Cadwallader, L.C.

    2001-01-31

    This report is an initial effort to identify issues affecting reliability and availability of solid and liquid wall designs for magnetic fusion power plant designs. A qualitative approach has been used to identify the possible failure modes of major system components and their effects on the systems. A general set of design attributes known to affect the service reliability has been examined for the overview solid and liquid wall designs, and some specific features of good first wall design have been discussed and applied to these designs as well. The two generalized designs compare well in regard to these design attributes. The strengths and weaknesses of each design approach are seen in the comparison of specific features.

  1. Automated diagnosis of mammogram images of breast cancer using discrete wavelet transform and spherical wavelet transform features: a comparative study.

    PubMed

    Ganesan, Karthikeyan; Acharya, U Rajendra; Chua, Chua Kuang; Min, Lim Choo; Abraham, Thomas K

    2014-12-01

    Mammograms are one of the most widely used techniques for preliminary screening of breast cancers. There is great demand for early detection and diagnosis of breast cancer using mammograms. Texture based feature extraction techniques are widely used for mammographic image analysis. In specific, wavelets are a popular choice for texture analysis of these images. Though discrete wavelets have been used extensively for this purpose, spherical wavelets have rarely been used for Computer-Aided Diagnosis (CAD) of breast cancer using mammograms. In this work, a comparison of the performance between the features of Discrete Wavelet Transform (DWT) and Spherical Wavelet Transform (SWT) based on the classification results of normal, benign and malignant stage was studied. Classification was performed using Linear Discriminant Classifier (LDC), Quadratic Discriminant Classifier (QDC), Nearest Mean Classifier (NMC), Support Vector Machines (SVM) and Parzen Classifier (ParzenC). We have obtained a maximum classification accuracy of 81.73% for DWT and 88.80% for SWT features using SVM classifier.

  2. Functional Characteristics of Intelligent Computer-Assisted Instruction: Intelligent Features.

    ERIC Educational Resources Information Center

    Park, Ok-choon

    1988-01-01

    Examines the functional characteristics of intelligent computer assisted instruction (ICAI) and discusses the requirements of a multidisciplinary cooperative effort of its development. A typical ICAI model is presented and intelligent features of ICAI systems are described, including modeling the student's learning process, qualitative decision…

  3. Quantitative analysis of qualitative images

    NASA Astrophysics Data System (ADS)

    Hockney, David; Falco, Charles M.

    2005-03-01

    We show optical evidence that demonstrates artists as early as Jan van Eyck and Robert Campin (c1425) used optical projections as aids for producing their paintings. We also have found optical evidence within works by later artists, including Bermejo (c1475), Lotto (c1525), Caravaggio (c1600), de la Tour (c1650), Chardin (c1750) and Ingres (c1825), demonstrating a continuum in the use of optical projections by artists, along with an evolution in the sophistication of that use. However, even for paintings where we have been able to extract unambiguous, quantitative evidence of the direct use of optical projections for producing certain of the features, this does not mean that paintings are effectively photographs. Because the hand and mind of the artist are intimately involved in the creation process, understanding these complex images requires more than can be obtained from only applying the equations of geometrical optics.

  4. Microemulsions: A qualitative thermodynamic approach

    SciTech Connect

    Kahlweit, M.; Strey, R.; Busse, G. )

    1990-05-17

    Microemulsions, that is, stable colloidal dispersions of water and nonpolar solvents stabilized by amphiphiles, are of growing interest in research and industry. The phase behavior of the multicomponent mixture is essentially determined by the features of corresponding binary mixtures. The efficiency of an amphiphile in solubilizing the solvents reaches its maximum in the temperature interval in which the mixture separates into three coexisting liquid phases. The domain size of the dispersion is determined by the interfacial tension between the aqueous and the oil-rich phase in the presence of a saturated monolayer. Because the interfacial tension reaches its minimum in the three-phase interval and, furthermore, decreases with increasing amphiphilicity, the transition from weakly structured solutions to microemulsions is gradual. It is, therefore, suggested that microemulsions be defined as stable colloidal dispersions of domains sufficiently large for the dispersed solvent to exhibit the properties as, e.g., the dielectric number of a bulk phase.

  5. Qualitative models for space system engineering

    NASA Astrophysics Data System (ADS)

    Forbus, Kenneth D.

    1990-06-01

    The objectives of this project were: (1) to investigate the implications of qualitative modeling techniques for problems arising in the monitoring, diagnosis, and design of Space Station subsystems and procedures; (2) to identify the issues involved in using qualitative models to enhance and automate engineering functions. These issues include representing operational criteria, fault models, alternate ontologies, and modeling continuous signals at a functional level of description; and (3) to develop a prototype collection of qualitative models for fluid and thermal systems commonly found in Space Station subsystems. Potential applications of qualitative modeling to space-systems engineering, including the notion of intelligent computer-aided engineering are summarized. Emphasis is given to determining which systems of the proposed Space Station provide the most leverage for study, given the current state of the art. Progress on using qualitative models, including development of the molecular collection ontology for reasoning about fluids, the interaction of qualitative and quantitative knowledge in analyzing thermodynamic cycles, and an experiment on building a natural language interface to qualitative reasoning is reported. Finally, some recommendations are made for future research.

  6. Qualitative models for space system engineering

    NASA Technical Reports Server (NTRS)

    Forbus, Kenneth D.

    1990-01-01

    The objectives of this project were: (1) to investigate the implications of qualitative modeling techniques for problems arising in the monitoring, diagnosis, and design of Space Station subsystems and procedures; (2) to identify the issues involved in using qualitative models to enhance and automate engineering functions. These issues include representing operational criteria, fault models, alternate ontologies, and modeling continuous signals at a functional level of description; and (3) to develop a prototype collection of qualitative models for fluid and thermal systems commonly found in Space Station subsystems. Potential applications of qualitative modeling to space-systems engineering, including the notion of intelligent computer-aided engineering are summarized. Emphasis is given to determining which systems of the proposed Space Station provide the most leverage for study, given the current state of the art. Progress on using qualitative models, including development of the molecular collection ontology for reasoning about fluids, the interaction of qualitative and quantitative knowledge in analyzing thermodynamic cycles, and an experiment on building a natural language interface to qualitative reasoning is reported. Finally, some recommendations are made for future research.

  7. Qualitative Differences between Learning Environments Using Videos in Small Groups and Whole Class Discussions: A Preliminary Study in Physics

    ERIC Educational Resources Information Center

    Mayo, Ashleigh; Sharma, Manjula D.; Muller, Derek A.

    2009-01-01

    Interactivity, group learning and student engagement are accepted as key features of social constructivist learning theories. The challenge is to understand the interplay between such features in different learning environments. This study focused on the qualitative differences between two interventions--small-groups and whole-class discussions.…

  8. Qualitative and Quantitative Analysis for Facial Complexion in Traditional Chinese Medicine

    PubMed Central

    Zhao, Changbo; Li, Guo-zheng; Li, Fufeng; Wang, Zhi; Liu, Chang

    2014-01-01

    Facial diagnosis is an important and very intuitive diagnostic method in Traditional Chinese Medicine (TCM). However, due to its qualitative and experience-based subjective property, traditional facial diagnosis has a certain limitation in clinical medicine. The computerized inspection method provides classification models to recognize facial complexion (including color and gloss). However, the previous works only study the classification problems of facial complexion, which is considered as qualitative analysis in our perspective. For quantitative analysis expectation, the severity or degree of facial complexion has not been reported yet. This paper aims to make both qualitative and quantitative analysis for facial complexion. We propose a novel feature representation of facial complexion from the whole face of patients. The features are established with four chromaticity bases splitting up by luminance distribution on CIELAB color space. Chromaticity bases are constructed from facial dominant color using two-level clustering; the optimal luminance distribution is simply implemented with experimental comparisons. The features are proved to be more distinctive than the previous facial complexion feature representation. Complexion recognition proceeds by training an SVM classifier with the optimal model parameters. In addition, further improved features are more developed by the weighted fusion of five local regions. Extensive experimental results show that the proposed features achieve highest facial color recognition performance with a total accuracy of 86.89%. And, furthermore, the proposed recognition framework could analyze both color and gloss degrees of facial complexion by learning a ranking function. PMID:24967342

  9. Qualitative and quantitative reasoning about thermodynamics

    NASA Technical Reports Server (NTRS)

    Skorstad, Gordon; Forbus, Ken

    1989-01-01

    One goal of qualitative physics is to capture the tacit knowledge of engineers and scientists. It is shown how Qualitative Process theory can be used to express concepts of engineering thermodynamics. In particular, it is shown how to integrate qualitative and quantitative knowledge to solve textbook problems involving thermodynamic cycles, such as gas turbine plants and steam power plants. These ideas were implemented in a program called SCHISM. Its analysis of a sample textbook problem is described and plans for future work are discussed.

  10. The use of triangulation in qualitative research.

    PubMed

    Carter, Nancy; Bryant-Lukosius, Denise; DiCenso, Alba; Blythe, Jennifer; Neville, Alan J

    2014-09-01

    Triangulation refers to the use of multiple methods or data sources in qualitative research to develop a comprehensive understanding of phenomena (Patton, 1999). Triangulation also has been viewed as a qualitative research strategy to test validity through the convergence of information from different sources. Denzin (1978) and Patton (1999) identified four types of triangulation: (a) method triangulation, (b) investigator triangulation, (c) theory triangulation, and (d) data source triangulation. The current article will present the four types of triangulation followed by a discussion of the use of focus groups (FGs) and in-depth individual (IDI) interviews as an example of data source triangulation in qualitative inquiry.

  11. New method for generating breast models featuring glandular tissue spatial distribution

    NASA Astrophysics Data System (ADS)

    Paixão, L.; Oliveira, B. B.; Oliveira, M. A.; Teixeira, M. H. A.; Fonseca, T. C. F.; Nogueira, M. S.

    2016-02-01

    Mammography is the main radiographic technique used for breast imaging. A major concern with mammographic imaging is the risk of radiation-induced breast cancer due to the high sensitivity of breast tissue. The mean glandular dose (DG) is the dosimetric quantity widely accepted to characterize the risk of radiation induced cancer. Previous studies have concluded that DG depends not only on the breast glandular content but also on the spatial distribution of glandular tissue within the breast. In this work, a new method for generating computational breast models featuring skin composition and glandular tissue distribution from patients undergoing digital mammography is proposed. Such models allow a more accurate way of calculating individualized breast glandular doses taking into consideration the glandular tissue fraction. Sixteen breast models of four patients with different glandularity breasts were simulated and the results were compared with those obtained from recommended DG conversion factors. The results show that the internationally recommended conversion factors may be overestimating the mean glandular dose to less dense breasts and underestimating the mean glandular dose for denser breasts. The methodology described in this work constitutes a powerful tool for breast dosimetry, especially for risk studies.

  12. Open-Ended Tasks and the Qualitative Investigation of Second Language Classroom Discourse

    ERIC Educational Resources Information Center

    Kahn, Gabrielle

    2012-01-01

    Grounded in Vygotskyan sociocultural theory, this qualitative, classroom-based investigation incorporates an open-ended task framework. Open tasks in the present study were defined as ones designed to take shape in the second language classroom as teacher and adult learners jointly worked through exploratory problems. One central feature of open…

  13. New Directions in Research: Contemporary Qualitative Research Methodologies and Issues in Literacy Education

    ERIC Educational Resources Information Center

    Tobin, Joseph; Steinkuehler, Constance A.; Black, Rebecca W.; Clinton, Katherine A.; Hinchman, Kathleen A.; Dillon, Deborah R.

    2005-01-01

    Scholars who are drawn to qualitative research methodologies represent a diverse group of disciplines and fields. They also represent themselves as researchers and the theoretical frameworks in which they work quite differently. Indeed, it was this diversity in representation that initially motivated us to propose a New Directions feature on…

  14. Qualitative Analysis of Information Communication Technology Use on Teaching-Learning Process.

    ERIC Educational Resources Information Center

    Akahori, Kanji

    This paper describes some of the features of Information Communication Technology (ICT) and its uses in the teaching-learning process in elementary schools. In most schools, it is difficult for ICT to be used effectively in the teaching-learning process. The author observed many classes using ICT in elementary schools. Qualitative data, such as…

  15. A Well Tempered Mammographic Display

    DTIC Science & Technology

    1998-09-01

    ambient light levels. A calibration procedure was developed that derived a display function for the mammogram display based upon equalizing the just...noticeable difference in contrast over the intensity range of the monitor at ambient illumination. The maximum and minimum pixel intensity determined... medio -lateral oblique views was developed. The time to detection and the detection accuracy using ROC analysis was compared for two radiologists reading

  16. Stereotactic (Mammographically Guided) Breast Biopsy

    MedlinePlus

    ... any medications you’re taking, including aspirin and herbal supplements, and whether you have any allergies – especially to ... doctor all medications that you are taking, including herbal supplements, and if you have any allergies, especially to ...

  17. Stereotactic (Mammographically Guided) Breast Biopsy

    MedlinePlus

    ... medical conditions. top of page What does the equipment look like? The specialized mammography machine used in ... can be obtained at different angles. At most facilities, a specially designed examination table will allow you ...

  18. Hormonal Determinants of Mammographic Density

    DTIC Science & Technology

    2005-08-01

    58: 196-204, 1993. 63. Seeger H, Mueck AO, and Lippert TH Effect of norethisterone acetate on estrogen metabolism in postmenopausal women. Horm Metab...Res 15:2513-2520. 77. Seeger H, Mueck AO, Lippert TH. (2000). Effect of norethisterone acetate on estrogen metabolism in postmenopausal women. Horm...and laryngeal papillomatosis: a pilot study. Anticancer Res 18: 4569-4573. 95. Lippert TH, Seeger H, Mueck AO. (1998). Estradiol metabolism during

  19. Hormonal Determinants of Mammographic Density

    DTIC Science & Technology

    2004-08-01

    63. Seeger H, Mueck AO, and Lippert TH Effect of norethisterone acetate on estrogen metabolism in postmenopausal women. Horm Metab Res, 32: 436-439...Seeger H, Mueck AO, Lippert TH. (2000). Effect of norethisterone acetate on estrogen metabolism in postmenopausal women. Horm Metab Res 32:436-439. 78...papillomatosis: a pilot study. Anticancer Res 18: 4569-4573. 95. Lippert TH, Seeger H, Mueck AO. (1998). Estradiol metabolism during oral and transdermal

  20. Fishing for Features

    ScienceCinema

    Heredia-Langner, Alejandro; Cort, John; Bailey, Vanessa

    2016-08-24

    The Fishing for Features Signature Discovery project developed a framework for discovering signature features in challenging environments involving large and complex data sets or where phenomena may be poorly characterized or understood. Researchers at PNNL have applied the framework to the optimization of biofuels blending and to discover signatures of climate change on microbial soil communities.

  1. Fishing for Features

    SciTech Connect

    Heredia-Langner, Alejandro; Cort, John; Bailey, Vanessa

    2016-07-21

    The Fishing for Features Signature Discovery project developed a framework for discovering signature features in challenging environments involving large and complex data sets or where phenomena may be poorly characterized or understood. Researchers at PNNL have applied the framework to the optimization of biofuels blending and to discover signatures of climate change on microbial soil communities.

  2. Defeating feature fatigue.

    PubMed

    Rust, Roland T; Thompson, Debora Viana; Hamilton, Rebecca W

    2006-02-01

    Consider a coffeemaker that offers 12 drink options, a car with more than 700 features on the dashboard, and a mouse pad that's also a clock, calculator, and FM radio. All are examples of "feature bloat", or "featuritis", the result of an almost irresistible temptation to load products with lots of bells and whistles. The problem is that the more features a product boasts, the harder it is to use. Manufacturers that increase a product's capability--the number of useful functions it can perform--at the expense of its usability are exposing their customers to feature fatigue. The authors have conducted three studies to gain a better understanding of how consumers weigh a product's capability relative to its usability. They found that even though consumers know that products with more features are harder to use, they initially choose high-feature models. They also pile on more features when given the chance to customize a product for their needs. Once consumers have actually worked with a product, however, usability starts to matter more to them than capability. For managers in consumer products companies, these findings present a dilemma: Should they maximize initial sales by designing high-feature models, which consumers consistently choose, or should they limit the number of features in order to enhance the lifetime value of their customers? The authors' analytical model guides companies toward a happy middle ground: maximizing the net present value of the typical customer's profit stream. The authors also advise companies to build simpler products, help consumers learn which products suit their needs, develop products that do one thing very well, and design market research in which consumers use actual products or prototypes.

  3. JCE Feature Columns

    NASA Astrophysics Data System (ADS)

    Holmes, Jon L.

    1999-05-01

    The Features area of JCE Online is now readily accessible through a single click from our home page. In the Features area each column is linked to its own home page. These column home pages also have links to them from the online Journal Table of Contents pages or from any article published as part of that feature column. Using these links you can easily find abstracts of additional articles that are related by topic. Of course, JCE Online+ subscribers are then just one click away from the entire article. Finding related articles is easy because each feature column "site" contains links to the online abstracts of all the articles that have appeared in the column. In addition, you can find the mission statement for the column and the email link to the column editor that I mentioned above. At the discretion of its editor, a feature column site may contain additional resources. As an example, the Chemical Information Instructor column edited by Arleen Somerville will have a periodically updated bibliography of resources for teaching and using chemical information. Due to the increase in the number of these resources available on the WWW, it only makes sense to publish this information online so that you can get to these resources with a simple click of the mouse. We expect that there will soon be additional information and resources at several other feature column sites. Following in the footsteps of the Chemical Information Instructor, up-to-date bibliographies and links to related online resources can be made available. We hope to extend the online component of our feature columns with moderated online discussion forums. If you have a suggestion for an online resource you would like to see included, let the feature editor or JCE Online (jceonline@chem.wisc.edu) know about it. JCE Internet Features JCE Internet also has several feature columns: Chemical Education Resource Shelf, Conceptual Questions and Challenge Problems, Equipment Buyers Guide, Hal's Picks, Mathcad

  4. Time Varying Feature Data

    NASA Astrophysics Data System (ADS)

    Echterhoff, J.; Simonis, I.; Atkinson, R.

    2012-04-01

    The infrastructure to gather, store and access information about our environment is improving and growing rapidly. The increasing amount of information allows us to get a better understanding of the current state of our environment, historical processes and to simulate and predict the future state of the environment. Finer grained spatial and temporal data and more reliable communications make it easier to model dynamic states and ephemeral features. The exchange of information within and across geospatial domains is facilitated through the use of harmonized information models. The Observations & Measurements (O&M) developed through OGC and standardised by ISO is an example of such a cross-domain information model. It is used in many domains, including meteorology, hydrology as well as the emergency management. O&M enables harmonized representation of common metadata that belong to the act of determining the state of a feature property, whether by sensors, simulations or humans. In addition to the resulting feature property value, information such as the result quality but especially the time that the result applies to the feature property can be represented. Temporal metadata is critical to modelling past and future states of a feature. The features, and the semantics of each property, are defined in domain specific Application Schema using the General Feature Model (GFM) from ISO 19109 and usually encoded following ISO 19136. However, at the moment these standards provide only limited support for the representation and handling of time varying feature data. Features like rivers, wildfires or gas plumes have a defined state - for example geographic extent - at any given point in time. To keep track of changes, a more complex model for example using time-series coverages is required. Furthermore, the representation and management of feature property value changes via the service interfaces defined by OGC and ISO - namely: WFS and WCS - would be rather complex

  5. Validity, reliability, and generalizability in qualitative research

    PubMed Central

    Leung, Lawrence

    2015-01-01

    In general practice, qualitative research contributes as significantly as quantitative research, in particular regarding psycho-social aspects of patient-care, health services provision, policy setting, and health administrations. In contrast to quantitative research, qualitative research as a whole has been constantly critiqued, if not disparaged, by the lack of consensus for assessing its quality and robustness. This article illustrates with five published studies how qualitative research can impact and reshape the discipline of primary care, spiraling out from clinic-based health screening to community-based disease monitoring, evaluation of out-of-hours triage services to provincial psychiatric care pathways model and finally, national legislation of core measures for children's healthcare insurance. Fundamental concepts of validity, reliability, and generalizability as applicable to qualitative research are then addressed with an update on the current views and controversies. PMID:26288766

  6. Perils and potentials in qualitative psychology.

    PubMed

    Brinkmann, Svend

    2015-06-01

    Famously, Ebbinghaus declared that psychology has a long past, but only a short history. Psychology, as something implicit to human conduct, is as old as the human race, but the science, as an explicit investigative reflection upon that conduct, is a recent invention. Within the short history of psychology, we find an even shorter history of qualitative psychology specifically. Although most founding fathers (Freud, Piaget, Bartlett etc.) worked as "qualitative psychologists", they found no need to thematize their methods of inquiry in this manner. Since around 1980, however, a field has established itself that can be called qualitative psychology. In this paper, I discuss how this field can move sensibly into the future, and I highlight two perils and two potentials. The perils stem from neo-positivism and a threatening "McDonaldization" of qualitative research, while the potentials are related to proliferation of new forms of inquiry and a transcending of disciplinary boundaries.

  7. Microcalcifications in 1657 Patients with Pure Ductal Carcinoma in Situ of the Breast: Correlation with Clinical, Histopathologic, Biologic Features and Local Recurrence

    PubMed Central

    Rauch, Gaiane M.; Hobbs, Brian P.; Kuerer, Henry M.; Scoggins, Marion E.; Benveniste, Ana P.; Park, Young Mi; Caudle, Abigail S.; Fox, Patricia S.; Smith, Benjamin D.; Adrada, Beatriz E.; Krishnamurthy, Savitri; Yang, Wei T.

    2016-01-01

    Purpose To determine the relationship of microcalcification morphology and distribution with clinical, histopathologic, biologic features and local recurrence (LR) in patients with pure ductal carcinoma in situ (DCIS) of the breast. Methods All patients with pure DCIS who underwent preoperative mammography at our institution from 1996 through 2009 were identified. Mammographic findings were classified according to the ACR BI-RADS lexicon. Associations between mammographic findings and clinical, histopathologic, biologic characteristics and LR were analyzed. Statistical inference used multiple logistic regression and Cox proportional hazards regression adjusted for age and confounding due to bias from nonrandomized selection of radiation therapy. Results We identified 1657 patients with microcalcifications visualized on mammography. The mean age at diagnosis was 55 years (SD, 11). The mean follow-up was 7 years (range, 1–16). Ipsilateral LR was 4% in segmentectomy (987) and 1.5% in mastectomy (670) patients. Increased LR risk was seen in patients with dense breast tissue (p<0.05) and larger DCIS size (p<0.01). Radiation therapy was associated with a 2.8-fold decrease in the LR risk. Fine linear (branching) microcalcifications were associated with 5.2-fold increase in LR. Extremely dense breast tissue was associated with positive/close margins (p=0.04) and multicentricity (p<0.01). Younger women were more likely to have extremely dense breast tissue (p<0.0001), multicentric disease (p<0.0004), and undergo mastectomy (p<0.0001). Conclusions Dense breast tissue, large DCIS size, and fine linear (branching) microcalcifications were associated with increased LR, yet overall LR rates remained low. Extremely dense breast tissue was a risk factor for multicentricity and positive margins in DCIS. PMID:26416712

  8. [Framework analysis method in qualitative research].

    PubMed

    Liao, Xing; Liu, Jian-ping; Robison, Nicola; Xie, Ya-ming

    2014-05-01

    In recent years a number of qualitative research methods have gained popularity within the health care arena. Despite this popularity, different qualitative analysis methods pose many challenges to most researchers. The present paper responds to the needs expressed by recent Chinese medicine researches. The present paper is mainly focused on the concepts, nature, application of framework analysis, especially on how to use it, in such a way to assist the newcomer of Chinese medicine researchers to engage with the methodology.

  9. Qualitative and Quantitative Proofs of Security Properties

    DTIC Science & Technology

    2013-04-01

    AFRL-OSR-VA-TR-2013-0207 Qualitative and Quantitative Proofs of Security Properties Joseph Halpern Cornell University...data soun ::es, gathering and maintaining the data needed, and completing and reviewing the collection of Information. Send comments regarding this...SUBTITLE 5a. CONTRACT NUMBER Qualitative and Quoatitivae Proofs of Security Properties 5b. GRANT NUMBER FA9550-09-l-0226 5c. PROGRAM ELEMENT NUMBER

  10. Qualitative Evaluation of Health Information Exchange Efforts

    PubMed Central

    Ash, Joan S.; Guappone, Kenneth P.

    2007-01-01

    Because most health information exchange (HIE) initiatives are as yet immature, formative evaluation is recommended so that what is learned through evaluation can be immediately applied to assist in HIE development efforts. Qualitative methods can be especially useful for formative evaluation because they can guide ongoing HIE growth while taking context into consideration. This paper describes important HIE-related research questions and outlines appropriate qualitative research techniques for addressing them. PMID:17904914

  11. New features in MEDM.

    SciTech Connect

    Evans, K., Jr.

    1999-04-13

    MEDM, which is derived from Motif Editor and Display Manager, is the primary graphical interface to the EPICS control system. This paper describes new features that have been added to MEDM in the last two years. These features include new editing capabilities, a PV Info dialog box, a means of specifying limits and precision, a new implementation of the Cartesian Plot, new features for several objects, new capability for the Related Display, help, a user-configurable Execute Menu, reconfigured start-up options, and availability for Windows 95/98/NT. Over one hundred bugs have been fixed, and the program is quite stable and in extensive use.

  12. Emergence of network features from multiplexity

    PubMed Central

    Cardillo, Alessio; Gómez-Gardeñes, Jesús; Zanin, Massimiliano; Romance, Miguel; Papo, David; Pozo, Francisco del; Boccaletti, Stefano

    2013-01-01

    Many biological and man-made networked systems are characterized by the simultaneous presence of different sub-networks organized in separate layers, with links and nodes of qualitatively different types. While during the past few years theoretical studies have examined a variety of structural features of complex networks, the outstanding question is whether such features are characterizing all single layers, or rather emerge as a result of coarse-graining, i.e. when going from the multilayered to the aggregate network representation. Here we address this issue with the help of real data. We analyze the structural properties of an intrinsically multilayered real network, the European Air Transportation Multiplex Network in which each commercial airline defines a network layer. We examine how several structural measures evolve as layers are progressively merged together. In particular, we discuss how the topology of each layer affects the emergence of structural properties in the aggregate network. PMID:23446838

  13. Knowledge representation and qualitative simulation of salmon redd functioning. Part I: qualitative modeling and simulation.

    PubMed

    Guerrin, F; Dumas, J

    2001-02-01

    This work aims at representing empirical knowledge of freshwater ecologists on the functioning of salmon redds (spawning areas of salmon) and its impact on mortality of early stages. For this, we use Qsim, a qualitative simulator. In this first part, we provide unfamiliar readers with the underlying qualitative differential equation (QDE) ontology of Qsim: representing quantities, qualitative variables, qualitative constraints, QDE structure. Based on a very simple example taken of the salmon redd application, we show how informal biological knowledge may be represented and simulated using an approach that was first intended to analyze qualitatively ordinary differential equations systems. A companion paper (Part II) gives the full description and simulation of the salmon redd qualitative model. This work was part of a project aimed at assessing the impact of the environment on salmon populations dynamics by the use of models of processes acting at different levels: catchment, river, and redds. Only the latter level is dealt with in this paper.

  14. Doing qualitative research in dentistry and dental education.

    PubMed

    Edmunds, S; Brown, G

    2012-05-01

    The purpose of this paper is to assist dental researchers to develop their expertise in qualitative research. It sketches the key characteristics of qualitative research; summarises theoretical perspectives; outlines the core skills of qualitative data collection and the procedures which underlie three methods of qualitative research: interviewing, focus groups and concept maps. The paper offers some guidance on writing qualitative research and provides examples of qualitative research drawn from dentistry and dental education.

  15. Volcanic features of Io

    USGS Publications Warehouse

    Carr, M.H.; Masursky, H.; Strom, R.G.; Terrile, R.J.

    1979-01-01

    Volcanic activity is apparently higher on Io than on any other body in the Solar System. Its volcanic landforms can be compared with features on Earth to indicate the type of volcanism present on Io. ?? 1979 Nature Publishing Group.

  16. AQUATOX Features and Tools

    EPA Pesticide Factsheets

    Numerous features have been included to facilitate the modeling process, from model setup and data input, presentation and analysis of results, to easy export of results to spreadsheet programs for additional analysis.

  17. Feature Leads That Work.

    ERIC Educational Resources Information Center

    Konkle, Bruce E.

    1999-01-01

    Presents advice to scholastic journalists on writing leads for feature stories. Discusses using a summary, a question, a direct quote, a first-person account, alliteration, a shocking statement, contrast, historical reference, descriptions, narratives, metaphors, and similes. (RS)

  18. Feature Characterization Library

    SciTech Connect

    Doyle, Wendy; Gentile, Ann; McCoy, Renata

    2006-08-03

    FCLib is a data analysis toolkit constructed to meet the needs of data discovery in large-scale, spatio-temporal data such as finite element simulation data. FCLib is a C library toolkit of building blocks that can be assembled into complex analyses. Important features of FCLib include the following: (1) Support of feature-based analysis, (2) minimization of low-oevel processing, (3) ease of use, and (4) applicable to the wide variety of science domains.

  19. Regression with Qualitative and Quantitative Variables: An Alternating Least Squares Method with Optimal Scaling Features

    ERIC Educational Resources Information Center

    And Others; Young, Forrest W.

    1976-01-01

    A method is discussed which extends canonical regression analysis to the situation where the variables may be measured as nominal, ordinal, or interval, and where they may be either continuous or discrete. The method, which is purely descriptive, uses an alternating least squares algorithm and is robust. Examples are provided. (Author/JKS)

  20. Comparative Qualitative Research Distinguishing Safety Features Among Aviation Safety Action Programs in the United States Airlines

    NASA Astrophysics Data System (ADS)

    Chilakalapudi, Naga Swathi Kiran

    Over the years, aviation safety has been influenced by continuous implementations of both proactive and reactive policies by both regulatory boards and also, aviation service providers. This achievement has been possible mainly because of the safety management tools like the Aviation Safety Action Program (ASAP) which derives its roots from the much earlier Aviation Safety Reporting System (ASRS). Federal Aviation Administration (FAA) provides guidelines and procedures for installation and development of an ASAP, for every airline in the United States. In this study, how different United States air carriers apply ASAP in their organizations is investigated.

  1. Interactive music composition driven by feature evolution.

    PubMed

    Kaliakatsos-Papakostas, Maximos A; Floros, Andreas; Vrahatis, Michael N

    2016-01-01

    Evolutionary music composition is a prominent technique for automatic music generation. The immense adaptation potential of evolutionary algorithms has allowed the realisation of systems that automatically produce music through feature and interactive-based composition approaches. Feature-based composition employs qualitatively descriptive music features as fitness landmarks. Interactive composition systems on the other hand, derive fitness directly from human ratings and/or selection. The paper at hand introduces a methodological framework that combines the merits of both evolutionary composition methodologies. To this end, a system is presented that is organised in two levels: the higher level of interaction and the lower level of composition. The higher level incorporates the particle swarm optimisation algorithm, along with a proposed variant and evolves musical features according to user ratings. The lower level realizes feature-based music composition with a genetic algorithm, according to the top level features. The aim of this work is not to validate the efficiency of the currently utilised setup in each level, but to examine the convergence behaviour of such a two-level technique in an objective manner. Therefore, an additional novelty in this work concerns the utilisation of artificial raters that guide the system through the space of musical features, allowing the exploration of its convergence characteristics: does the system converge to optimal melodies, is this convergence fast enough for potential human listeners and is the trajectory to convergence "interesting' and "creative" enough? The experimental results reveal that the proposed methodological framework represents a fruitful and robust, novel approach to interactive music composition.

  2. The Systems Biology Markup Language (SBML) Level 3 Package: Qualitative Models, Version 1, Release 1.

    PubMed

    Chaouiya, Claudine; Keating, Sarah M; Berenguier, Duncan; Naldi, Aurélien; Thieffry, Denis; van Iersel, Martijn P; Le Novère, Nicolas; Helikar, Tomáš

    2015-09-04

    Quantitative methods for modelling biological networks require an in-depth knowledge of the biochemical reactions and their stoichiometric and kinetic parameters. In many practical cases, this knowledge is missing. This has led to the development of several qualitative modelling methods using information such as, for example, gene expression data coming from functional genomic experiments. The SBML Level 3 Version 1 Core specification does not provide a mechanism for explicitly encoding qualitative models, but it does provide a mechanism for SBML packages to extend the Core specification and add additional syntactical constructs. The SBML Qualitative Models package for SBML Level 3 adds features so that qualitative models can be directly and explicitly encoded. The approach taken in this package is essentially based on the definition of regulatory or influence graphs. The SBML Qualitative Models package defines the structure and syntax necessary to describe qualitative models that associate discrete levels of activities with entity pools and the transitions between states that describe the processes involved. This is particularly suited to logical models (Boolean or multi-valued) and some classes of Petri net models can be encoded with the approach.

  3. Turning Points in Qualitative Research: Tying Knots in a Handkerchief. Crossroads in Qualitative Inquiry Series.

    ERIC Educational Resources Information Center

    Lincoln, Yvonna S., Ed.; Denzin, Norman K., Ed.

    The chapters of this volume traces the changes in the discipline of qualitative inquiry over the last five decades. The collection serves as a textbook for training scholars in the history and trajectory of qualitative research. The chapters of part 1, The Revolution of Representation: Feminist and Race/Ethnic Studies Discourses, are: (1) Situated…

  4. Building Interdisciplinary Qualitative Research Networks: Reflections on Qualitative Research Group (QRG) at the University of Manitoba

    ERIC Educational Resources Information Center

    Roger, Kerstin Stieber; Halas, Gayle

    2012-01-01

    As qualitative research methodologies continue to evolve and develop, both students and experienced researchers are showing greater interest in learning about and developing new approaches. To meet this need, faculty at the University of Manitoba created the Qualitative Research Group (QRG), a community of practice that utilizes experiential…

  5. [Qualitative Research in Health Services Research - Discussion Paper, Part 3: Quality of Qualitative Research].

    PubMed

    Stamer, M; Güthlin, C; Holmberg, C; Karbach, U; Patzelt, C; Meyer, T

    2015-12-01

    The third and final discussion paper of the German Network of Health Services Research's (DNVF) "Qualitative Methods Working Group" demonstrates methods for the evaluation and quality of qualitative research in health services research. In this paper we discuss approaches described in evaluating qualitative studies, including: an orientation to the general principles of empirical research, an approach-specific course of action, as well as procedures based on the research-process and criteria-oriented approaches. Divided into general and specific aspects to be considered in a qualitative study quality evaluation, the central focus of the discussion paper undertakes an extensive examination of the process and criteria-oriented approaches. The general aspects include the participation of relevant groups in the research process as well as ethical aspects of the research and data protection issues. The more specific aspects in evaluating the quality of qualitative research include considerations about the research interest, research questions, and the selection of data collection methods and types of analyses. The formulated questions are intended to guide reviewers and researchers to evaluate and to develop qualitative research projects appropriately. The intention of this discussion paper is to ensure a transparent research culture, and to reflect on and discuss the methodological and research approach of qualitative studies in health services research. With this paper we aim to initiate a discussion on high quality evaluation of qualitative health services research.

  6. Disrupting Qualitative Inquiry: Possibilities and Tensions in Educational Research. Critical Qualitative Research. Volume 10

    ERIC Educational Resources Information Center

    Brown, Ruth Nicole, Ed.; Carducci, Rozana, Ed.; Kuby, Candace R., Ed.

    2014-01-01

    "Disrupting Qualitative Inquiry" is an edited volume that examines the possibilities and tensions encountered by scholars who adopt disruptive qualitative approaches to the study of educational contexts, issues, and phenomena. It presents a collection of innovative and intellectually stimulating chapters which illustrate the potential…

  7. Conducting Qualitative Data Analysis: Reading Line-by-Line, but Analyzing by Meaningful Qualitative Units

    ERIC Educational Resources Information Center

    Chenail, Ronald J.

    2012-01-01

    In the first of a series of "how-to" essays on conducting qualitative data analysis, Ron Chenail points out the challenges of determining units to analyze qualitatively when dealing with text. He acknowledges that although we may read a document word-by-word or line-by-line, we need to adjust our focus when processing the text for purposes of…

  8. Conducting Qualitative Data Analysis: Qualitative Data Analysis as a Metaphoric Process

    ERIC Educational Resources Information Center

    Chenail, Ronald J.

    2012-01-01

    In the second of a series of "how-to" essays on conducting qualitative data analysis, Ron Chenail argues the process can best be understood as a metaphoric process. From this orientation he suggests researchers follow Kenneth Burke's notion of metaphor and see qualitative data analysis as the analyst systematically considering the "this-ness" of…

  9. Three featured plenary sessions

    NASA Astrophysics Data System (ADS)

    2012-07-01

    The conference included three plenary sessions. The plenary on Governance, Security, Economy, and the Ecosystem of the Changing Arctic featured Vera Alexander, president, Arctic Research Consortium of the U.S.; Alan Thornhill, chief environmental officer, U.S. Department of the Interior's Bureau of Ocean Energy Management; and Fran Ulmer, chair, U.S. Arctic Research Commission. A plenary on the U.N. Convention on the Law of the Sea featured Ambassador David Balton, deputy assistant secretary for oceans and fisheries, U.S. Department of State; and Rear Admiral Frederick Kenney Jr., judge advocate general and chief counsel, U.S. Coast Guard. The plenary on Science and the 21st Century featured Phil Keslin, chief technology officer, small lab within Google.

  10. [Special methodology, qualitative methods and abstract concepts].

    PubMed

    Delgado, Ana R

    2010-08-01

    Generally speaking, this paper comments on the role of qualitative methods in scientific psychology. To begin with, general and special methodology are defined; then, the main uses of qualitative methods are described and the focus of the paper on the study of meaning and of abstract concepts in the context of embodied cognition is justified. It is emphasized that three uses of qualitative methods converge in the study of embodied cognition: (1) classification, given that it is centered on concepts, (2) discovery, because theories are not yet well articulated and inductive effort is required, and (3) the study of meaning. The final recommendation is to profit from the opportunity of constructing special techniques that the transformation of cognitive psychology is favoring; in this context, varieties of emotion become a privileged object of study.

  11. Propagating Qualitative Values Through Quantitative Equations

    NASA Technical Reports Server (NTRS)

    Kulkarni, Deepak

    1992-01-01

    In most practical problems where traditional numeric simulation is not adequate, one need to reason about a system with both qualitative and quantitative equations. In this paper, we address the problem of propagating qualitative values represented as interval values through quantitative equations. Previous research has produced exponential-time algorithms for approximate solution of the problem. These may not meet the stringent requirements of many real time applications. This paper advances the state of art by producing a linear-time algorithm that can propagate a qualitative value through a class of complex quantitative equations exactly and through arbitrary algebraic expressions approximately. The algorithm was found applicable to Space Shuttle Reaction Control System model.

  12. Analyzing qualitative data with computer software.

    PubMed Central

    Weitzman, E A

    1999-01-01

    OBJECTIVE: To provide health services researchers with an overview of the qualitative data analysis process and the role of software within it; to provide a principled approach to choosing among software packages to support qualitative data analysis; to alert researchers to the potential benefits and limitations of such software; and to provide an overview of the developments to be expected in the field in the near future. DATA SOURCES, STUDY DESIGN, METHODS: This article does not include reports of empirical research. CONCLUSIONS: Software for qualitative data analysis can benefit the researcher in terms of speed, consistency, rigor, and access to analytic methods not available by hand. Software, however, is not a replacement for methodological training. PMID:10591282

  13. Escalator design features evaluation

    NASA Technical Reports Server (NTRS)

    Zimmerman, W. F.; Deshpande, G. K.

    1982-01-01

    Escalators are available with design features such as dual speed (90 and 120 fpm), mat operation and flat steps. These design features were evaluated based on the impact of each on capital and operating costs, traffic flow, and safety. A human factors engineering model was developed to analyze the need for flat steps at various speeds. Mat operation of escalators was found to be cost effective in terms of energy savings. Dual speed operation of escalators with the higher speed used during peak hours allows for efficient operation. A minimum number of flat steps required as a function of escalator speed was developed to ensure safety for the elderly.

  14. Spirituality Concept by Health Professionals in Iran: A Qualitative Study.

    PubMed

    Memaryan, Nadereh; Rassouli, Maryam; Mehrabi, Maryam

    2016-01-01

    Background. For years, researchers have sought to provide a clear definition of spirituality and its features and consequences, but the definitions provided of this concept still lack transparency. The present qualitative research was conducted to clarify this concept within the religious-cultural context of Iran. Materials and Methods. The present conventional qualitative content analysis was conducted with an inductive approach. Data were collected through semistructured interviews with 17 spiritual health experts and activists selected through purposive sampling. Results. Three themes emerged from the analysis of the data, including (1) the structure of spirituality, (2) defects in the conceptualization of spirituality, and (3) spirituality in practice, which are explained in this paper with their relevant subthemes and codes. The definition which this study proposes for this concept is that "spirituality is the sublime aspect of human existence bestowed on all humans in order for them to traverse the path of transcendence that is closeness to God (Allah)." Conclusion. The definition provided by this study is similar to the previous definitions of this concept in its main part (transcendence) and in incorporating a God-centered view of spirituality within the context of an Islamic society. This definition has implications for health services' education, research, and practice in similar societies.

  15. Spirituality Concept by Health Professionals in Iran: A Qualitative Study

    PubMed Central

    2016-01-01

    Background. For years, researchers have sought to provide a clear definition of spirituality and its features and consequences, but the definitions provided of this concept still lack transparency. The present qualitative research was conducted to clarify this concept within the religious-cultural context of Iran. Materials and Methods. The present conventional qualitative content analysis was conducted with an inductive approach. Data were collected through semistructured interviews with 17 spiritual health experts and activists selected through purposive sampling. Results. Three themes emerged from the analysis of the data, including (1) the structure of spirituality, (2) defects in the conceptualization of spirituality, and (3) spirituality in practice, which are explained in this paper with their relevant subthemes and codes. The definition which this study proposes for this concept is that “spirituality is the sublime aspect of human existence bestowed on all humans in order for them to traverse the path of transcendence that is closeness to God (Allah).” Conclusion. The definition provided by this study is similar to the previous definitions of this concept in its main part (transcendence) and in incorporating a God-centered view of spirituality within the context of an Islamic society. This definition has implications for health services' education, research, and practice in similar societies. PMID:27493675

  16. "It's exercise or nothing": a qualitative analysis of exercise dependence

    PubMed Central

    Bamber, D; Cockerill, I; Rodgers, S; Carroll, D

    2000-01-01

    Objectives—To explore, using qualitative methods, the concept of exercise dependence. Semistructured interviews were undertaken with subjects screened for exercise dependence and eating disorders. Methods—Female exercisers, four in each case, were allocated a priori to four groups: primary exercise dependent; secondary exercise dependent, where there was a coincidence of exercise dependence and an eating disorder; eating disordered; control, where there was no evidence of either exercise dependence or eating disorder. They were asked about their exercise and eating attitudes and behaviour, as well as about any history of psychological distress. Their narratives were taped, transcribed, and analysed from a social constructionist perspective using QSR NUD*IST. Results—Participants classified as primary exercise dependent either showed no evidence of exercise dependent attitudes and behaviour or, if they exhibited features of exercise dependence, displayed symptoms of an eating disorder. Only the latter reported a history of psychological distress, similar to that exhibited by women classified as secondary exercise dependent or eating disordered. For secondary exercise dependent and eating disordered women, as well as for controls, the narratives largely confirmed the a priori classification. Conclusions—Where exercise dependence was manifest, it was always in the context of an eating disorder, and it was this co-morbidity, in addition to eating disorders per se, that was associated with psychological distress. As such, these qualitative data support the concept of secondary, but not primary, exercise dependence. Key Words: exercise dependence; eating disorders; psychological distress; anorexia; bulimia PMID:11131229

  17. Ethnicity and the prostate cancer experience: a qualitative metasynthesis

    PubMed Central

    Matheson, Lauren; Nayoan, Johana; Glaser, Adam; Gavin, Anna; Wright, Penny; Wagland, Richard; Watson, Eila

    2016-01-01

    Abstract Objectives To summarize black and minority ethnic (BME) patients' and partners experiences of prostate cancer by examining the findings of existing qualitative studies. Methods We undertook a systematic metasynthesis of qualitative studies using a modified version of Noblit and Hare's “meta‐ethnography” approach, with a 2000‐2015 search of 7 databases. Results Thirteen studies of men from US and UK BME groups were included. We explored constructs with BME‐specific features. Health care provider relationships, formation of a spiritual alliance with God (which enhanced the participants' feeling of empowerment and ability to cope with the cancer), and living on for others (generally to increase cancer awareness), often connected to spiritual regrowth, were the 3 constructs most commonly reported. A magnified effect from erectile dysfunction was also common. Initially, this affected men's disclosure to others about their cancer and their sexual problems, but eventually men responded by shifting their conceptualizations of masculinity to sustain self and social identities. There was also evidence of inequality resulting from financial constraints and adversity that necessitated resilience in coping. Conclusions The prostate cancer experience of BME men and their partners is affected by a complex intersection of ethnicity with other factors. Health care services should acknowledge this. If providers recognize the men's felt masculinities, social identities, and spiritual beliefs and their shifting nature, services could be improved, with community as well as individual benefits. More studies are needed in diverse ethnic groups. PMID:27416079

  18. Reasoning about energy in qualitative simulation

    NASA Technical Reports Server (NTRS)

    Fouche, Pierre; Kuipers, Benjamin J.

    1992-01-01

    While possible behaviors of a mechanism that are consistent with an incomplete state of knowledge can be predicted through qualitative modeling and simulation, spurious behaviors corresponding to no solution of any ordinary differential equation consistent with the model may be generated. The present method for energy-related reasoning eliminates an important source of spurious behaviors, as demonstrated by its application to a nonlinear, proportional-integral controlled. It is shown that such qualitative properties of such a system as stability and zero-offset control are captured by the simulation.

  19. Qualitätsmanagement in der Lebensmittelindustrie

    NASA Astrophysics Data System (ADS)

    Thorn, Volker

    Die wesentlichen Kunden der Lebensmittelindustrie sind der Einzel- und Großhandel und die Verbraucher. Jedes Unternehmen kann mittel- und langfristig nur existieren, wenn seine Kunden zufrieden sind. Kunden sind zufrieden, wenn ihre Erwartungen, die sie an Produkt, Service und Preis stellen, erfüllt werden. Also die bestimmte erwartete Qualität (Leistung) sichergestellt wird. Trotz aller Bemühungen und Anstrengungen der Anbieter, Qualitätsprodukte auf den Markt zu bringen, kames in den letzten Jahren immer wieder zu Lebensmittelskandalen.

  20. From conditional oughts to qualitative decision theory

    NASA Technical Reports Server (NTRS)

    Pearl, Judea

    1994-01-01

    The primary theme of this investigation is a decision theoretic account of conditional ought statements (e.g., 'You ought to do A, if C') that rectifies glaring deficiencies in classical deontic logic. The resulting account forms a sound basis for qualitative decision theory, thus providing a framework for qualitative planning under uncertainty. In particular, we show that adding causal relationships (in the form of a single graph) as part of an epistemic state is sufficient to facilitate the analysis of action sequences, their consequences, their interaction with observations, their expected utilities, and the synthesis of plans and strategies under uncertainty.

  1. Conducting Qualitative Data Analysis: Managing Dynamic Tensions within

    ERIC Educational Resources Information Center

    Chenail, Ronald J.

    2012-01-01

    In the third of a series of "how-to" essays on conducting qualitative data analysis, Ron Chenail examines the dynamic tensions within the process of qualitative data analysis that qualitative researchers must manage in order to produce credible and creative results. These tensions include (a) the qualities of the data and the qualitative data…

  2. Special Feature: Graphic Communications.

    ERIC Educational Resources Information Center

    Davidhazy, Andrew; And Others

    1993-01-01

    Special feature includes "There's More to Blur than Meets the Eye" (Davidhazy), about photographic imaging; "Photography Lab's Silver Lining" (Borchers), about recycling silver; "Budget-Priced Layout Programs for School Publishing with DPT [Desktop Publishing]" (Dose); and "Good Learning and Good PR--All in One…

  3. Assistive Technologies, Feature Issue.

    ERIC Educational Resources Information Center

    Wobschall, Rachel, Ed.; Lakin, Charlie, Ed.

    1995-01-01

    This feature issue of a newsletter on community integration of individuals with developmental disabilities considers the role of assistive technologies. It describes efforts to utilize consumer direction, public policy, creativity, energy, and professional know-how in the pursuit of technology-based opportunities to enhance community inclusion,…

  4. Integrated Education. Feature Issue.

    ERIC Educational Resources Information Center

    York, Jennifer, Ed.; Vandercook, Terri, Ed.

    1988-01-01

    This "feature issue" provides various perspectives on a number of integrated education topics, including successful integration practices and strategies, the changing roles of teachers, the appropriate role of research, the history and future of integrated education, and the realization of dreams of life in the mainstream for children with severe…

  5. Main features of meiosis

    SciTech Connect

    1993-12-31

    Chapter 17, outlines the main features of meiosis, beginning with its significance and proceeding through the meiotic stages. Meiosis is the most important modification of mitosis because it is the reduction division that gives rise to the haploid generation in the life cycle. 17 refs., 6 figs.

  6. Transition. Feature Issue.

    ERIC Educational Resources Information Center

    Wallace, Teri, Ed.; And Others

    1992-01-01

    This feature issue of a quarterly bulletin on community integration addresses the topic of transition services for preparing youth with disabilities for adult community living. It contains articles with the following titles and authors: "Transition: The Next Five Years" (David R. Johnson and others); "Transition Policy in the 1990s:…

  7. CATS Featured Articles

    Atmospheric Science Data Center

    2017-01-31

      CATS Featured Articles       A Slice of Cirrus: Image of ... just hours before by the Cloud-Aerosol Transport System (CATS) onboard the International Space Station. Nighttime View of Raung Volcanic Plume : Natural Hazards  - The CATS instrument slices through darkness to reveal the vertical structure of a ...

  8. Dialog on a country path: the qualitative research journey.

    PubMed

    Sorrell, Jeanne M; Cangelosi, Pamela R; Dinkins, Christine S

    2014-03-01

    There is little information in the literature describing how students learn qualitative research. This article describes an approach to learning that is based on the pedagogical approach of Dinkins' Socratic-Hermeneutic Shared Inquiry. This approach integrates shared dialog as an essential aspect of learning. The qualitative pedagogy described in this article focused on three questions: What is knowing in qualitative research? How do we come to know qualitative research? What can we do with qualitative research? Students learned the basics of qualitative research within a context that fostered interpretive inquiry. In this way, the course framework mirrored the combination of interviewing, storytelling, and journeying toward understanding that constitute qualitative research.

  9. Using Qualitative Methods to Inform Scale Development

    ERIC Educational Resources Information Center

    Rowan, Noell; Wulff, Dan

    2007-01-01

    This article describes the process by which one study utilized qualitative methods to create items for a multi dimensional scale to measure twelve step program affiliation. The process included interviewing fourteen addicted persons while in twelve step focused treatment about specific pros (things they like or would miss out on by not being…

  10. Enhancing Institutional Assessment Efforts through Qualitative Methods

    ERIC Educational Resources Information Center

    Van Note Chism, Nancy; Banta, Trudy W.

    2007-01-01

    Qualitative methods can do much to describe context and illuminate the why behind patterns encountered in institutional assessment. Alone, or in combination with quantitative methods, they should be the approach of choice for many of the most important assessment questions. (Contains 1 table.)

  11. The mathematical bases for qualitative reasoning

    NASA Technical Reports Server (NTRS)

    Kalagnanam, Jayant; Simon, Herbert A.; Iwasaki, Yumi

    1991-01-01

    The practices of researchers in many fields who use qualitative reasoning are summarized and explained. The goal is to gain an understanding of the formal assumptions and mechanisms that underlie this kind of analysis. The explanations given are based on standard mathematical formalisms, particularly on ordinal properties, continuous differentiable functions, and the mathematics of nonlinear dynamic systems.

  12. Qualitative Inquiry in Clinical and Educational Settings

    ERIC Educational Resources Information Center

    Hays, Danica G.; Singh, Anneliese A.

    2011-01-01

    This highly readable text demystifies the qualitative research process--and helps readers conceptualize their own studies--by organizing the different research paradigms and traditions into coherent clusters. Real-world examples and firsthand perspectives illustrate the research process; instructive exercises and activities build on each other so…

  13. The Ethics of Qualitative Nursing Research.

    ERIC Educational Resources Information Center

    Robley, Lois R.

    1995-01-01

    Ethical issues in qualitative nursing research include the following: what to study, which participants, what methods, how to achieve informed consent, when to terminate interviews and when to probe, when treatment should supersede research, and what and how to document in case studies. (SK)

  14. Asian American Career Development: A Qualitative Analysis

    ERIC Educational Resources Information Center

    Fouad, Nadya A.; Kantamneni, Neeta; Smothers, Melissa K.; Chen, Yung-Lung; Fitzpatrick, Mary; Terry, Sarah

    2008-01-01

    This study used a modified version of consensual qualitative research design to examine how contextual, cultural, and personal variables influence the career choices of a diverse group of 12 Asian Americans. Seven domains of influences on career choices emerged including family, culture, external factors, career goals, role models, work values,…

  15. Qualitative Description of College Students' Dinner Groups

    ERIC Educational Resources Information Center

    Ball, Brita; Brown, Lora Beth

    2012-01-01

    Objective: To discover how college students conduct dinner groups and perceptions of the benefits and difficulties of participation. Design: Qualitative study conducted with 7 focus groups. Setting and Participants: A university campus, with 36 students participating in dinner groups, defined as a group of 3 people or more cooking for one another…

  16. Qualitative Interviewing as an Embodied Emotional Performance

    ERIC Educational Resources Information Center

    Ezzy, Douglas

    2010-01-01

    The article argues that the emotional framing of interviews plays a major role in shaping the content of interviews. Drawing on the psychoanalytic theory of Jessica Benjamin and Luce Irigaray, the article describes how interviews can be experienced as either conquest or communion. Qualitative researchers typically focus on the cognitively…

  17. Qualitative Graphing: A Construction in Mathematics.

    ERIC Educational Resources Information Center

    Narode, Ronald

    This document argues that qualitative graphing is an effective introduction to mathematics as a construction for communication of ideas involving quantitative relationships. It is suggested that with little or no prior knowledge of Cartesian coordinates or analytic descriptions of graphs using equations students can successfully grasp concepts of…

  18. Qualitative Research Practice in Adult Education.

    ERIC Educational Resources Information Center

    Willis, Peter, Ed.; Neville, Bernie, Ed.

    This collection of 20 papers is aimed at researchers, research students, and research supervisors interested in qualitative research into facilitated adult learning in the workplace, formal education programs, professional development, and community settings. "Introduction" (Willis) provides a summary of the papers. "Qualitative…

  19. Dilemmas and Further Debates in Qualitative Method

    ERIC Educational Resources Information Center

    Shenton, Andrew K.; Hay-Gibson, Naomi V.

    2009-01-01

    Newcomers to the qualitative method encounter a seemingly bewildering array of issues when taking their first steps in tackling a project of this type. Novices may well be confused by matters on which even expert commentators disagree and may find themselves confronting situations in which they realise that, by attending to one criterion, their…

  20. Interrogating Racism in Qualitative Research Methodology. Counterpoints.

    ERIC Educational Resources Information Center

    Lopez, Gerardo R., Ed.; Parker, Laurence, Ed.

    This book explores the link between critical race theory and qualitative research methodology, interrogating how race connects and conflicts with other areas of difference and is never entirely absent from the research process. After an introduction, "Critical Race Theory in Education: Theory, Praxis, and Recommendations" (Sylvia R.…

  1. A Qualitative Data Collection Strategy for Africa

    DTIC Science & Technology

    2013-02-01

    ms Ne tw or k (F EW SN ET...In this study, sponsored by the Rapid Reaction Technology Office (RRTO) in the Office of the Deputy Assistant Secretary of Defense for Rapid Fielding...simulations, and other computational tools ( MS &T) for analysis of Africa. Through the identification of gaps in qualitative data, IDA developed

  2. Qualitative Investigation of Young Children's Music Preferences

    ERIC Educational Resources Information Center

    Roulston, Kathryn

    2006-01-01

    This qualitative study examined young children's music preferences through group conversations with children, interviews with parents, and non-participant observation of classroom settings in daycare and elementary classrooms. Data were analyzed inductively to generate themes, and revealed that (1) children expressed distinct preferences for an…

  3. Innovative Data Collection Strategies in Qualitative Research

    ERIC Educational Resources Information Center

    Onwuegbuzie, Anthony J.; Leech, Nancy L.; Collins, Kathleen M. T.

    2010-01-01

    This article provides an innovative meta-framework comprising strategies designed to guide qualitative data collection in the 21st century. We present a meta-framework comprising strategies for collecting data from interviews, focus groups, observations, and documents/material culture. We present a template for collecting nonverbal data during…

  4. Why Students Procrastinate: A Qualitative Approach

    ERIC Educational Resources Information Center

    Klingsieck, Katrin B.; Grund, Axel; Schmid, Sebastian; Fries, Stefan

    2013-01-01

    In this study we adopted an impartial view on academic procrastination in order to gain new insights for the development of intervention programs. Following a qualitative approach, we thereby explored antecedents of procrastination by attending to the actual voices and experiences of 29 students. Students' subjective theories were in line…

  5. Collecting and Interpreting Qualitative Materials. Third Edition

    ERIC Educational Resources Information Center

    Denzin, Norman K., Ed.; Lincoln, Yvonna, Ed.

    2007-01-01

    This book is the third volume of the paperback versions of "The SAGE Handbook of Qualitative Research, Third Edition." This portion of the handbook considers the tasks of collecting, analyzing, and interpreting empirical materials, and comprises the Handbook's Parts IV ("Methods of Collecting and Analyzing Empirical Materials") and V ("The Art and…

  6. Qualitative Research in Education: A User's Guide

    ERIC Educational Resources Information Center

    Lichtman, Marilyn

    2006-01-01

    This book provides those new to the field with a blend of practical and theoretical information. The author addresses a spectrum of recent information about the process of qualitative educational research and brings together in one volume the essential elements of all aspects of the field. The text: (1) Introduces traditions and influences in the…

  7. Qualitative Interviewing: The Art of Hearing Data.

    ERIC Educational Resources Information Center

    Rubin, Herbert J.; Rubin, Irene S.

    Intended for students and for researchers who conduct interviews as part of case studies or as ethnography, this book provides a comprehensive, up-to-date introduction to the theory and practice of qualitative interviewing. It shows researchers how to design research based on interview data; to stimulate conversation; to absorb what is being said;…

  8. Culturally Competent Qualitative Research with Latino Immigrants

    ERIC Educational Resources Information Center

    Ojeda, Lizette; Flores, Lisa Y.; Meza, Rocio Rosales; Morales, Alejandro

    2011-01-01

    This article provides recommendations for conducting culturally competent qualitative research with Latino immigrants, a historically exploited group that represents more than half of all U.S. immigrants and is continuously growing. Limited research exists on Latino immigrants despite their large presence in the United States. The authors draw…

  9. Facilitating Coherence across Qualitative Research Papers

    ERIC Educational Resources Information Center

    Chenail, Ronald J.; Duffy, Maureen; St. George, Sally; Wulff, Dan

    2011-01-01

    Bringing the various elements of qualitative research papers into coherent textual patterns presents challenges for authors and editors alike. Although individual sections such as presentation of the problem, review of the literature, methodology, results, and discussion may each be constructed in a sound logical and structural sense, the…

  10. Martini Qualitative Research: Shaken, Not Stirred

    ERIC Educational Resources Information Center

    Nieuwenhuis, F. J.

    2015-01-01

    Although the number of qualitative research studies has boomed in recent years, close observation reveals that often the research designs and methodological considerations and approaches have developed a type of configuration that does not adhere to purist definitions of the labels attached. Very often so called interpretivist studies are not…

  11. Values in Qualitative and Quantitative Research

    ERIC Educational Resources Information Center

    Duffy, Maureen; Chenail, Ronald J.

    2008-01-01

    The authors identify the philosophical underpinnings and value-ladenness of major research paradigms. They argue that useful and meaningful research findings for counseling can be generated from both qualitative and quantitative research methodologies, provided that the researcher has an appreciation of the importance of philosophical coherence in…

  12. Ethical Issues in Qualitative Research. Comments.

    ERIC Educational Resources Information Center

    Gottlieb, Alma

    In recent years, many in anthropology have been challenging the positivist paradigm that dominated the field, with its assumption of the researcher as a transparent data gatherer and the notion of data as something to be collected through fieldwork. Questions of qualitative research methodology are also surfacing in education even as the divisions…

  13. School Improvement Teams: A Qualitative Perspective.

    ERIC Educational Resources Information Center

    Maloy, Robert W.; Fischetti, John C.

    1985-01-01

    The authors identify and discuss four components of teamwork in the Boston Secondary Schools Project: team viewpoints, team roles and power, team projects, and team continuity. The discussion is based on findings from a variety of qualitative and research techniques including interviews, participant observations studies, and content analysis of…

  14. Developing Qualitative Research Questions: A Reflective Process

    ERIC Educational Resources Information Center

    Agee, Jane

    2009-01-01

    The reflective and interrogative processes required for developing effective qualitative research questions can give shape and direction to a study in ways that are often underestimated. Good research questions do not necessarily produce good research, but poorly conceived or constructed questions will likely create problems that affect all…

  15. A Qualitative Ethnographic Portrait of Women's Studies

    ERIC Educational Resources Information Center

    Rosser, Julee L.

    2013-01-01

    In this research study, I sought to understand and describe the Women's and Gender Studies (WGS) Program at Berea College by exploring it through the experiences of students, faculty, administrators, and alumnae. I designed and implemented a feminist organizational ethnography. Organizational ethnography is a naturalistic, qualitative research…

  16. The Challenges of Qualitatively Coding Ancient Texts

    ERIC Educational Resources Information Center

    Slingerland, Edward; Chudek, Maciej

    2012-01-01

    We respond to several important and valid concerns about our study ("The Prevalence of Folk Dualism in Early China," "Cognitive Science" 35: 997-1007) by Klein and Klein, defending our interpretation of our data. We also argue that, despite the undeniable challenges involved in qualitatively coding texts from ancient cultures,…

  17. Peer Helpers in Hungary: A Qualitative Analysis

    ERIC Educational Resources Information Center

    Racz, Jozsef; Lacko, Zsuzsa

    2008-01-01

    Hungary is a country in transition that has no real tradition of peer helping. A qualitative study was carried out involving 13 peer helpers of two kinds (a) age-based peers, and (b) way-of-life-based peers (fellow helpers). The motivations for and the processes of becoming a peer helper were analyzed. Results showed the largest difference being…

  18. Feature Selection in the Tensor Product Feature Space

    PubMed Central

    Smalter, Aaron; Huan, Jun; Lushington, Gerald

    2014-01-01

    Classifying objects that are sampled jointly from two or more domains has many applications. The tensor product feature space is useful for modeling interactions between feature sets in different domains but feature selection in the tensor product feature space is challenging. Conventional feature selection methods ignore the structure of the feature space and may not provide the optimal results. In this paper we propose methods for selecting features in the original feature spaces of different domains. We obtained sparsity through two approaches, one using integer quadratic programming and another using L1-norm regularization. Experimental studies on biological data sets validate our approach. PMID:24632658

  19. Major depression with psychotic features

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/000933.htm Major depression with psychotic features To use the sharing features on this page, please enable JavaScript. Major depression with psychotic features is a mental disorder in ...

  20. North Polar Features

    NASA Technical Reports Server (NTRS)

    2004-01-01

    28 November 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows banded terrain of the north polar region of Mars. The bands are exposures of layered material, possibly composed of dust and ice. The dark, rounded to elliptical mounds in this image might be the locations of ancient sand dunes that were completely buried in the north polar layered material. In more recent times, these mounds have been exhumed from within the layered material. Alternatively, the dark features are not ancient, exhumed dunes, but perhaps the remnants of a dark layer of material that once covered the entire area shown in the image. These features are located near 79.9oN, 31.4oW. The image covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.

  1. Intrinsic Feature Motion Tracking

    SciTech Connect

    Goddard, Jr., James S.

    2013-03-19

    Subject motion during 3D medical scanning can cause blurring and artifacts in the 3D images resulting in either rescans or poor diagnosis. Anesthesia or physical restraints may be used to eliminate motion but are undesirable and can affect results. This software measures the six degree of freedom 3D motion of the subject during the scan under a rigidity assumption using only the intrinsic features present on the subject area being monitored. This movement over time can then be used to correct the scan data removing the blur and artifacts. The software acquires images from external cameras or images stored on disk for processing. The images are from two or three calibrated cameras in a stereo arrangement. Algorithms extract and track the features over time and calculate position and orientation changes relative to an initial position. Output is the 3D position and orientation change measured at each image.

  2. Ceraunius Tholus Feature

    NASA Technical Reports Server (NTRS)

    2004-01-01

    11 December 2004 Today's Mars Picture of the Day features two images. The top picture is a mosaic of Viking orbiter images acquired in the late 1970s. The lower image is a high resolution picture from the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC). The Viking mosaic shows Ceraunius Tholus, a volcano in the Tharsis region that was first viewed in images obtained by Mariner 9 in 1972. Several channels run down the slope of the Ceraunius Tholus volcano. The deepest of those channels ends in an elliptical crater. The elliptical crater was formed by a very oblique meteor impact. Where the channel meets the floor of the elliptical crater, there is a small mound of material. Presumably, this material was deposited in the elliptical crater after running down through the channel on the volcano's northwest flank.

    Near the top/center of the mound in the elliptical crater is a small, circular depression. Some have speculated for years that this depression is related to volcanism, others thought that it may be an impact crater. The MGS MOC image (lower of the two images) shows that crater. It is not the source of lava flows or any other volcanic features. Most likely, it is an old impact crater. This feature is located near 25.2oN, 97.7oW. The MOC image covers an area approximately 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left.

  3. Isidis Planitia Features

    NASA Technical Reports Server (NTRS)

    2004-01-01

    26 June 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows some of the most typical features of Isidis Planitia at full (1.5 meters -- 5 feet -- per pixel) resolution. The typical features are: (1) light-toned, ripple-like dunes and (2) mounds with summit pits. The dunes are formed by wind. The double-cone feature in the lower right quarter of the image is similar to many mounds and chains of mounds or cones found all across Isidis Planitia. These were seen at lower resolution in Viking orbiter images in the 1970s and were generally considered to be either small volcanoes or ice-cored mounds known as pingoes. With high resolution MOC images, it became apparent that many of these mounds may simply be the remnants of crater and pit chain floors, elevated above the surrounding plains as the layers of rock into which they formed were stripped away. Like much of Mars, there are more questions than answers. This image is located near 8.6oN, 268.2oW, and covers an area about 1.1 km (0.7 mi) wide. Sunlight illuminates the scene from the left/lower left.

  4. Predicting radiologists' true and false positive decisions in reading mammograms by using gaze parameters and image-based features

    NASA Astrophysics Data System (ADS)

    Gandomkar, Ziba; Tay, Kevin; Ryder, Will; Brennan, Patrick C.; Mello-Thoms, Claudia

    2016-03-01

    Radiologists' gaze-related parameters combined with image-based features were utilized to classify suspicious mammographic areas ultimately scored as True Positives (TP) and False Positives (FP). Eight breast radiologists read 120 two-view digital mammograms of which 59 had biopsy proven cancer. Eye tracking data was collected and nearby fixations were clustered together. Suspicious areas on mammograms were independently identified based on thresholding an intensity saliency map followed by automatic segmentation and pruning steps. For each radiologist reported area, radiologist's fixation clusters in the area, as well as neighboring suspicious areas within 2.5° of the center of fixation, were found. A 45-dimensional feature vector containing gaze parameters of the corresponding cluster along with image-based characteristics was constructed. Gaze parameters included total number of fixations in the cluster, dwell time, time to hit the cluster for the first time, maximum number of consecutive fixations, and saccade magnitude of the first fixation in the cluster. Image-based features consisted of intensity, shape, and texture descriptors extracted from the region around the suspicious area, its surrounding tissue, and the entire breast. For each radiologist, a userspecific Support Vector Machine (SVM) model was built to classify the reported areas as TPs or FPs. Leave-one-out cross validation was utilized to avoid over-fitting. A feature selection step was embedded in the SVM training procedure by allowing radial basis function kernels to have 45 scaling factors. The proposed method was compared with the radiologists' performance using the jackknife alternative free-response receiver operating characteristic (JAFROC). The JAFROC figure of merit increased significantly for six radiologists.

  5. Feature saltation and the evolution of mimicry.

    PubMed

    Gamberale-Stille, Gabriella; Balogh, Alexandra C V; Tullberg, Birgitta S; Leimar, Olof

    2012-03-01

    In Batesian mimicry, a harmless prey species imitates the warning coloration of an unpalatable model species. A traditional suggestion is that mimicry evolves in a two-step process, in which a large mutation first achieves approximate similarity to the model, after which smaller changes improve the likeness. However, it is not known which aspects of predator psychology cause the initial mutant to be perceived by predators as being similar to the model, leaving open the question of how the crucial first step of mimicry evolution occurs. Using theoretical evolutionary simulations and reconstruction of examples of mimicry evolution, we show that the evolution of Batesian mimicry can be initiated by a mutation that causes prey to acquire a trait that is used by predators as a feature to categorize potential prey as unsuitable. The theory that species gain entry to mimicry through feature saltation allows us to formulate scenarios of the sequence of events during mimicry evolution and to reconstruct an initial mimetic appearance for important examples of Batesian mimicry. Because feature-based categorization by predators entails a qualitative distinction between nonmimics and passable mimics, the theory can explain the occurrence of imperfect mimicry.

  6. Structured Qualitative Research: Organizing “Mountains of Words” for Data Analysis, both Qualitative and Quantitative

    PubMed Central

    Johnson, Bruce D.; Dunlap, Eloise; Benoit, Ellen

    2008-01-01

    Qualitative research creates mountains of words. U.S. federal funding supports mostly structured qualitative research, which is designed to test hypotheses using semi-quantitative coding and analysis. The authors have 30 years of experience in designing and completing major qualitative research projects, mainly funded by the US National Institute on Drug Abuse [NIDA]. This article reports on strategies for planning, organizing, collecting, managing, storing, retrieving, analyzing, and writing about qualitative data so as to most efficiently manage the mountains of words collected in large-scale ethnographic projects. Multiple benefits accrue from this approach. Several different staff members can contribute to the data collection, even when working from remote locations. Field expenditures are linked to units of work so productivity is measured, many staff in various locations have access to use and analyze the data, quantitative data can be derived from data that is primarily qualitative, and improved efficiencies of resources are developed. The major difficulties involve a need for staff who can program and manage large databases, and who can be skillful analysts of both qualitative and quantitative data. PMID:20222777

  7. Perceived needs in women with gestational diabetes: A qualitative study

    PubMed Central

    Khooshehchin, Taraneh Emamgoli; Keshavarz, Zohre; Afrakhteh, Maryam; Shakibazadeh, Elham; Faghihzadeh, Soghrat

    2016-01-01

    Introduction Diabetes is the most common medical complication of pregnancy. It can be associated with many complications for mother and fetus. Gestational diabetes is also one of the main health issues in Iran. Therefore, the present study is aimed at a deeper understanding of women’s experiences of gestational diabetes and their perceived needs to inform future lifestyle interventions. Methods This qualitative content analysis study was carried out in 2015. Participants were pregnant women diagnosed with gestational diabetes in the 24th to 36th week of pregnancy, who were referred to the clinics affiliated with Shahid Beheshti Medical Science University in Tehran, Iran. In-depth interviews were conducted with participants, using semi-structured questions. Interviews were audio taped and transcribed verbatim. Conventional content analysis was carried out for data analysis. Interviews continued until data saturation was obtained. Data were coded in MAXQDA software (version 11). Results Content analysis highlighted two themes; educational needs and need to support. The former was featured with five main categories: information sources, education process, unknown and known, weaknesses of public information system, and eagerness to learn. The latter was featured with two main categories: family support and social support. Conclusion Clarifying the needs of the mothers with gestational diabetes, leads to better and proper education planning and a program toward the improvement of health, self-care, and prevention of diabetes. PMID:28163857

  8. Features of MCNP6

    NASA Astrophysics Data System (ADS)

    Goorley, T.; James, M.; Booth, T.; Brown, F.; Bull, J.; Cox, L. J.; Durkee, J.; Elson, J.; Fensin, M.; Forster, R. A.; Hendricks, J.; Hughes, H. G.; Johns, R.; Kiedrowski, B.; Martz, R.; Mashnik, S.; McKinney, G.; Pelowitz, D.; Prael, R.; Sweezy, J.; Waters, L.; Wilcox, T.; Zukaitis, T.

    2014-06-01

    MCNP6 is simply and accurately described as the merger of MCNP5 and MCNPX capabilities, but it is much more than the sum of these two computer codes. MCNP6 is the result of six years of effort by the MCNP5 and MCNPX code development teams. These groups of people, residing in Los Alamos National Laboratory's X Computational Physics Division, Monte Carlo Codes Group (XCP-3) and Nuclear Engineering and Nonproliferation Division, Radiation Transport Modeling Team (NEN-5) respectively, have combined their code development efforts to produce the next evolution of MCNP. While maintenance and major bug fixes will continue for MCNP5 1.60 and MCNPX 2.7.0 for upcoming years, new code development capabilities only will be developed and released in MCNP6. In fact, the initial release of MCNP6 contains numerous new features not previously found in either code. These new features are summarized in this document. Packaged with MCNP6 is also the new production release of the ENDF/B-VII.1 nuclear data files usable by MCNP. The high quality of the overall merged code, usefulness of these new features, along with the desire in the user community to start using the merged code, have led us to make the first MCNP6 production release: MCNP6 version 1. High confidence in the MCNP6 code is based on its performance with the verification and validation test suites, comparisons to its predecessor codes, our automated nightly software debugger tests, the underlying high quality nuclear and atomic databases, and significant testing by many beta testers.

  9. Epignathus with Fetiform Features

    PubMed Central

    Kumar, Sunil Y; Shrikrishna, U; Shetty, Jayaprakash; Sitaram, Aishwarya

    2011-01-01

    Epignathus is an extremely rare oropharyngeal teratoma that commonly arises from the palate, leading to a high mortality (80–100%) due to airway obstruction in the neonatal period. We present a case of epignathus immature teratoma with fetiform features, originating from basisphenoid in a 28-week preterm male baby, who succumbed to death immediately after birth. Since epignathus is a life-threatening condition at the time of delivery, a prenatal diagnosis is essential to coordinate the treatment and appropriate management by securing the airway, either by endotracheal intubation or tracheostomy followed by complete resection of the tumor. PMID:21701667

  10. Tectonic features on Titan

    NASA Astrophysics Data System (ADS)

    Cook, C.; Barnes, J.

    2011-10-01

    This research is based on the exploration of tectonic patterns on Titan from a global perspective. Several moons in the outer solar system display known stress fields driven or modified by global forces which affect patterns of tectonism. Patterns such as these are seen in Europa's tidal forces, Enceladus' tiger strips, and Ganymede's global expansion. Given its proximity to Saturn, as well as its eccentric orbit, tectonic features and global stresses may be present on Titan as well. Titan displays visible tectonic structures, such as mountain chains along its equator (Radebaugh et al. 2007), as well as the unexplored Virgae.

  11. qFeature

    SciTech Connect

    2015-09-14

    This package contains statistical routines for extracting features from multivariate time-series data which can then be used for subsequent multivariate statistical analysis to identify patterns and anomalous behavior. It calculates local linear or quadratic regression model fits to moving windows for each series and then summarizes the model coefficients across user-defined time intervals for each series. These methods are domain agnostic—but they have been successfully applied to a variety of domains, including commercial aviation and electric power grid data.

  12. Using qualitative maps to direct reactive robots

    NASA Technical Reports Server (NTRS)

    Bertin, Randolph; Pendleton, Tom

    1992-01-01

    The principal advantage of mobile robots is that they are able to go to specific locations to perform useful tasks rather than have the tasks brought to them. It is important therefore that the robot be used to reach desired locations efficiently and reliably. A mobile robot whose environment extends significantly beyond its sensory horizon must maintain a representation of the environment, a map, in order to attain these efficiency and reliability requirements. We believe that qualitative mapping methods provide useful and robust representation schemes and that such maps may be used to direct the actions of a reactively controlled robot. In this paper we describe our experience in employing qualitative maps to direct, through the selection of desired control strategies, a reactive-behavior based robot. This mapping capability represents the development of one aspect of a successful deliberative/reactive hybrid control architecture.

  13. The ethics of qualitative nursing research.

    PubMed

    Robley, L R

    1995-01-01

    Nurse researchers conducting qualitative studies need to be acutely aware of the unique ways ethics, both nursing and research ethics, affect all phases of the qualitative research process. Decisions about what to study, which persons will be asked to participate, what methodology will be used, how to achieve truly informed consent, when to terminate or interrupt interviews, when to probe deeply, when therapy or nursing care supersedes research, and what and how case studies should be documented in the published results are all matters for ethical deliberation. This article seeks to examine some of the less obvious, yet very important, ethical concerns that nurses face throughout the research process and build a common core of values that can lead to meaningful process and socially responsible research results.

  14. Computer-assisted qualitative data analysis software.

    PubMed

    Cope, Diane G

    2014-05-01

    Advances in technology have provided new approaches for data collection methods and analysis for researchers. Data collection is no longer limited to paper-and-pencil format, and numerous methods are now available through Internet and electronic resources. With these techniques, researchers are not burdened with entering data manually and data analysis is facilitated by software programs. Quantitative research is supported by the use of computer software and provides ease in the management of large data sets and rapid analysis of numeric statistical methods. New technologies are emerging to support qualitative research with the availability of computer-assisted qualitative data analysis software (CAQDAS).CAQDAS will be presented with a discussion of advantages, limitations, controversial issues, and recommendations for this type of software use.

  15. Qualitative Reasoning for Additional Die Casting Applications

    SciTech Connect

    R. Allen Miller; Dehua Cui; Yuming Ma

    2003-05-28

    If manufacturing incompatibility of a product can be evaluated at the early product design stage, the designers can modify their design to reduce the effect of potential manufacturing problems. This will result in fewer manufacturing problems, less redsign, less expensive tooling, lower cost, better quality, and shorter development time. For a given design, geometric reasoning can predict qualitatively the behaviors of a physical manufacturing process by representing and reasoning with incomplete knowledge of the physical phenomena. It integrates a design with manufacturing processes to help designers simultaneously consider design goals and manufacturing constraints during the early design stage. The geometric reasoning approach can encourage design engineers to qualitatively evaluate the compatibility of their design with manufacturing limitations and requirements.

  16. Managing occurrence branching in qualitative simulation

    SciTech Connect

    Tokuda, L.

    1996-12-31

    Qualitative simulators can produce common sense abstractions of complex behaviors given only partial knowledge about a system. One of the problems which limits the applicability of qualitative simulators is the intractable branching of successor states encountered with model of even modest size. Some branches may be unavoidable due to the complex nature of a system. Other branches may be accidental results of the model chosen. A common source of intractability is occurrence branching. Occurrence branching occurs when the state transitions of two variables are unordered with respect to each other. This paper extends the QSIM model to distinguish between interesting occurrence branching and uninteresting occurrence branching. A representation, algorithm, and simulator for efficiently handling uninteresting branching is presented.

  17. Becoming and remaining homeless: a qualitative investigation.

    PubMed

    Morrell-Bellai, T; Goering, P N; Boydell, K M

    2000-09-01

    This article reports the qualitative findings of a multimethod study of the homeless population in Toronto, Canada. The qualitative component sought to identify how people become homeless and why some individuals remain homeless for an extended period of time or cycle in and out of homelessness (the chronically homeless). In-depth, semistructured interviews were conducted with 29 homeless adults. The findings suggest that people both become and remain homeless due to a combination of macro level factors (poverty, lack of employment, low welfare wages, lack of affordable housing) and personal vulnerability (childhood abuse or neglect, mental health symptoms, impoverished support networks, substance abuse). Chronically homeless individuals often reported experiences of severe childhood trauma and tended to attribute their continued homelessness to a substance abuse problem. It is concluded that both macro and individual level factors must be considered in planning programs and services to address the issue of homelessness in Canada.

  18. Generalized perceptual linear prediction features for animal vocalization analysis.

    PubMed

    Clemins, Patrick J; Johnson, Michael T

    2006-07-01

    A new feature extraction model, generalized perceptual linear prediction (gPLP), is developed to calculate a set of perceptually relevant features for digital signal analysis of animal vocalizations. The gPLP model is a generalized adaptation of the perceptual linear prediction model, popular in human speech processing, which incorporates perceptual information such as frequency warping and equal loudness normalization into the feature extraction process. Since such perceptual information is available for a number of animal species, this new approach integrates that information into a generalized model to extract perceptually relevant features for a particular species. To illustrate, qualitative and quantitative comparisons are made between the species-specific model, generalized perceptual linear prediction (gPLP), and the original PLP model using a set of vocalizations collected from captive African elephants (Loxodonta africana) and wild beluga whales (Delphinapterus leucas). The models that incorporate perceptional information outperform the original human-based models in both visualization and classification tasks.

  19. Qualitative differential games with two targets

    NASA Technical Reports Server (NTRS)

    Getz, W. M.; Leitmann, G.

    1977-01-01

    So-called differential games of kind (qualitative games) were considered involving two or more players each of whom possesses a target toward which he wished to steer the response of a dynamical system that was under the control of all players. Sufficient conditions were derived, which assure termination on a particular player's target. In general, these conditions were constructive in that they permited construction of a winning (terminating) strategy for a player. The theory is illustrated by a pursuit-evasion problem.

  20. Recursive Feature Extraction in Graphs

    SciTech Connect

    2014-08-14

    ReFeX extracts recursive topological features from graph data. The input is a graph as a csv file and the output is a csv file containing feature values for each node in the graph. The features are based on topological counts in the neighborhoods of each nodes, as well as recursive summaries of neighbors' features.

  1. Feature Engineering for Drug Name Recognition in Biomedical Texts: Feature Conjunction and Feature Selection

    PubMed Central

    Liu, Shengyu; Chen, Qingcai; Wang, Xiaolong; Fan, Xiaoming

    2015-01-01

    Drug name recognition (DNR) is a critical step for drug information extraction. Machine learning-based methods have been widely used for DNR with various types of features such as part-of-speech, word shape, and dictionary feature. Features used in current machine learning-based methods are usually singleton features which may be due to explosive features and a large number of noisy features when singleton features are combined into conjunction features. However, singleton features that can only capture one linguistic characteristic of a word are not sufficient to describe the information for DNR when multiple characteristics should be considered. In this study, we explore feature conjunction and feature selection for DNR, which have never been reported. We intuitively select 8 types of singleton features and combine them into conjunction features in two ways. Then, Chi-square, mutual information, and information gain are used to mine effective features. Experimental results show that feature conjunction and feature selection can improve the performance of the DNR system with a moderate number of features and our DNR system significantly outperforms the best system in the DDIExtraction 2013 challenge. PMID:25861377

  2. Feature engineering for drug name recognition in biomedical texts: feature conjunction and feature selection.

    PubMed

    Liu, Shengyu; Tang, Buzhou; Chen, Qingcai; Wang, Xiaolong; Fan, Xiaoming

    2015-01-01

    Drug name recognition (DNR) is a critical step for drug information extraction. Machine learning-based methods have been widely used for DNR with various types of features such as part-of-speech, word shape, and dictionary feature. Features used in current machine learning-based methods are usually singleton features which may be due to explosive features and a large number of noisy features when singleton features are combined into conjunction features. However, singleton features that can only capture one linguistic characteristic of a word are not sufficient to describe the information for DNR when multiple characteristics should be considered. In this study, we explore feature conjunction and feature selection for DNR, which have never been reported. We intuitively select 8 types of singleton features and combine them into conjunction features in two ways. Then, Chi-square, mutual information, and information gain are used to mine effective features. Experimental results show that feature conjunction and feature selection can improve the performance of the DNR system with a moderate number of features and our DNR system significantly outperforms the best system in the DDIExtraction 2013 challenge.

  3. Convolutional neural network features based change detection in satellite images

    NASA Astrophysics Data System (ADS)

    Mohammed El Amin, Arabi; Liu, Qingjie; Wang, Yunhong

    2016-07-01

    With the popular use of high resolution remote sensing (HRRS) satellite images, a huge research efforts have been placed on change detection (CD) problem. An effective feature selection method can significantly boost the final result. While hand-designed features have proven difficulties to design features that effectively capture high and mid-level representations, the recent developments in machine learning (Deep Learning) omit this problem by learning hierarchical representation in an unsupervised manner directly from data without human intervention. In this letter, we propose approaching the change detection problem from a feature learning perspective. A novel deep Convolutional Neural Networks (CNN) features based HR satellite images change detection method is proposed. The main guideline is to produce a change detection map directly from two images using a pretrained CNN. This method can omit the limited performance of hand-crafted features. Firstly, CNN features are extracted through different convolutional layers. Then, a concatenation step is evaluated after an normalization step, resulting in a unique higher dimensional feature map. Finally, a change map was computed using pixel-wise Euclidean distance. Our method has been validated on real bitemporal HRRS satellite images according to qualitative and quantitative analyses. The results obtained confirm the interest of the proposed method.

  4. Evaluating the feature comparison strategy for forensic face identification.

    PubMed

    Towler, Alice; White, David; Kemp, Richard I

    2017-03-01

    Face recognition is thought to rely on representations that encode holistic properties. Paradoxically, professional forensic examiners who identify unfamiliar faces by comparing facial images are trained to adopt a feature-by-feature comparison strategy. Here we tested the effectiveness of this strategy by asking participants to rate facial feature similarity prior to making same/different identity decisions to pairs of face images. Experiment 1 provided preliminary evidence that rating feature similarity improves unfamiliar face matching accuracy in novice participants. In Experiment 2, we found benefits of this procedure over and above rating similarity of personality traits and image quality parameters, suggesting that benefits are not solely attributable to general increases in attention. In Experiment 3, we then compared performance of trained forensic facial image examiners to novice participants, and found that examiners displayed: i) superior face matching accuracy; ii) smaller face inversion and feature inversion effects; and iii) feature ratings that were more diagnostic of identity. Further, aggregating feature ratings of multiple examiners produced perfect identity discrimination. Based on these quantitative and qualitative differences between experts and novices, we conclude that comparison based on local features confers specific benefits to trained forensic examiners. (PsycINFO Database Record

  5. Qualitative Theory and Methods in Applied Linguistics Research.

    ERIC Educational Resources Information Center

    Davis, Kathryn A.

    1995-01-01

    This article reviews basic issues of theory and method in qualitative research approaches to applied linguistics research, focusing on the ways in which qualitative research can contribute to an understanding of second-language acquisition and use. (83 references) (MDM)

  6. Qualitative research in psychology: Could William James get a job?

    PubMed

    Marchel, Carol; Owens, Stephanie

    2007-11-01

    Considering the case of William James, the author examines the likelihood of a successful career as a qualitative researcher in contemporary U.S. psychology. Fifty-seven journals affiliated with the American Psychological Association or its divisions were analyzed to show the place of qualitative research in U.S. psychology over the past 50 years. Journal abstracts, mission statements, and a short e-mail questionnaire from editors were used to understand patterns and trends in qualitative research in U.S. psychology. Editors are generally accepting of qualitative work, although mission statements do not always signal likely interest in qualitative work. The amount of qualitative work published is comparably low, but patterns of increased publication are found in some journals. Trends in methodologies, topics of research, and ways in which qualitative research enters journals over time are discussed. Suggestions for the publication of qualitative work are provided.

  7. Ensuring rigour and trustworthiness of qualitative research in clinical pharmacy.

    PubMed

    Hadi, Muhammad Abdul; José Closs, S

    2016-06-01

    The use of qualitative research methodology is well established for data generation within healthcare research generally and clinical pharmacy research specifically. In the past, qualitative research methodology has been criticized for lacking rigour, transparency, justification of data collection and analysis methods being used, and hence the integrity of findings. Demonstrating rigour in qualitative studies is essential so that the research findings have the "integrity" to make an impact on practice, policy or both. Unlike other healthcare disciplines, the issue of "quality" of qualitative research has not been discussed much in the clinical pharmacy discipline. The aim of this paper is to highlight the importance of rigour in qualitative research, present different philosophical standpoints on the issue of quality in qualitative research and to discuss briefly strategies to ensure rigour in qualitative research. Finally, a mini review of recent research is presented to illustrate the strategies reported by clinical pharmacy researchers to ensure rigour in their qualitative research studies.

  8. Dynamic features of combustion

    NASA Technical Reports Server (NTRS)

    Oppenheim, A. K.

    1985-01-01

    The dynamic features of combustion are discussed for four important cases: ignition, inflammation, explosion, and detonation. Ignition, the initiation of a self-sustained exothermic process, is considered in the simplest case of a closed thermodynamic system and its stochastic distribution. Inflammation, the initiation and propagation of self-sustained flames, is presented for turbulent flow. Explosion, the dynamic effects caused by the deposition of exothermic energy in a compressible medium, is illustrated by self-similar blast waves with energy deposition at the front and the adiabatic non-self-similar wave. Detonation, the most comprehensive illustration of all the dynamic effects of combustion, is discussed with a phenomenological account of the development and structure of the wave.

  9. [Qualitative Determination of Organic Vapour Using Violet and Visible Spectrum].

    PubMed

    Jiang, Bo; Hu, Wen-zhong; Liu, Chang-jian; Zheng, Wei; Qi, Xiao-hui; Jiang, Ai-li; Wang, Yan-ying

    2015-12-01

    Vapours of organic matters were determined qualitatively employed with ultraviolet-visible absorption spectroscopy. Vapours of organic matters were detected using ultraviolet-visible spectrophotometer employing polyethylene film as medium, the ultraviolet and visible absorption spectra of vegetable oil vapours of soybean oil, sunflower seed oil, peanut oil, rapeseed oil, sesame oil, cotton seed oil, tung tree seed oil, and organic compound vapours of acetone, ethyl acetate, 95% ethanol, glacial acetic acid were obtained. Experimental results showed that spectra of the vegetable oil vapour and the organic compound vapour could be obtained commendably, since ultra violet and visible spectrum of polyethylene film could be deducted by spectrograph zero setting. Different kinds of vegetable oils could been distinguished commendably in the spectra since the λ(max), λ(min), number of absorption peak, position, inflection point in the ultra violet and visible spectra obtained from the vapours of the vegetable oils were all inconsistent, and the vapours of organic compounds were also determined perfectly. The method had a good reproducibility, the ultraviolet and visible absorption spectra of the vapours of sunflower seed oil in 10 times determination were absolutely the same. The experimental result indicated that polyethylene film as a kind of medium could be used for qualitative analysis of ultraviolet and visible absorption spectroscopy. The method for determination of the vapours of the vegetable oils and organic compounds had the peculiarities of fast speed analysis, well reproducibility, accuracy and reliability and low cost, and so on. Ultraviolet and visible absorption spectrum of organic vapour could provide feature information of material vapour and structural information of organic compound, and provide a novel test method for identifying vapour of compound and organic matter.

  10. Is there any Correlation between Magnetic Resonance Imaging Features of Breast Lesions of BIRADS Category 4 with Histopathologic Results?

    PubMed Central

    Farghadani, Maryam; Soofi, Ghazale Jamalipoor; Sarrami, Amir Hossein

    2017-01-01

    Background: To evaluate the correlation of magnetic resonance imaging (MRI) features of breast lesions of Breast Imaging Reporting and Database System (BI-RADS) category 4 with histopathologic results. Materials and Methods: In a prospective study between December 2013 and April 2015, patients with suspicious mammographic and/or ultrasound findings referred for Breast MRI were evaluated. Patients with lesions of BI-RADS category 4 were enrolled with a written informed consent. In each patient, mass lesion (ML) or nonmass lesion (NML) was determined, and different characteristics of the lesions were recorded. A follow-up program was taken with mean 3–12 months. Patients who underwent core needle biopsy or open biopsy were summoned. Results: Seventy-eight females aged 24–67 years (mean 43.1 ± 8.8) met the inclusion criteria and had adequate samples for histopathologic study. Twenty-nine (37.2%) patients had ML and 49 (62.8%) patients had NML. Tissue sampling in 63 (80.7%) patients was through core needle biopsy and in 15 (19.2%) patients through surgery. A wide spectrum of benign and malignant pathologic diagnoses was seen. In statistical analysis, none of the MRI features has a significant correlation with any specific histopathologic diagnosis (P = 0.185). However, the relation between the MRI category (ML or NML) and pathology results was significant at level of 0.1 (P = 0.06). Conclusion: This study showed that a wide spectrum of histopathologic results is seen in BI-RADS category 4. However, in this sample volume, none of the MRI features in this BI-RADS category has a significant correlation with any specific histopathologic diagnosis. PMID:28217652

  11. Contribution of Haar wavelets and MPEG-7 textural features for false positive reduction in a CAD system for the detection of masses in mammograms

    NASA Astrophysics Data System (ADS)

    Eltonsy, Nevine H.; Tourassi, Georgia D.; Elmaghraby, Adel S.

    2007-03-01

    The study investigates the significance of wavelet-based and MPEG-7 homogeneous textural features in an attempt to improve the specificity of an in-house CAD system for the detection of masses in screening mammograms. The detection scheme has been presented before and it relies on the concept of morphologic concentric layer (MCL) analysis to identify suspicious locations in a mammogram. The locations were deemed suspicious due to their morphology; especially an increased activity of iso-intensity layers around these locations. On a set of 270 mammographic images, the MCL detection scheme achieved 93% (131/141) mass detection rate with 4.8 FPs/image (1,296/270). In the present study, the textural signature of the detected location is analyzed for possible false positive reduction. For texture analysis, HAAR wavelet and MPEG-7 HTD textural features were extracted. In addition, the contribution of directional neighborhood (DN) features was studied as well. The extracted features were combined with a back-propagation artificial neural network (BPANN) to discriminate true masses from false positives. Using a database of 1,427 suspicious seeds (131 true masses and 1,296 FPs) and a 5-fold cross-validation sampling scheme, the ROC area index of the BPNN using the different sets of features were as follows: A z(HAAR)=0.87+/-0.01, A z(HTD)=0.91+/-0.02, A z(DN)=0.84+/-0.01. Averaging the scores of the three BPANNs resulted in statistically significantly better performance A z(ALL)=0.94+/-0.01. At 95% sensitivity, the FP rate was reduced by 77.5%. The overall performance of the system after incorporation of textural and directional features was 87.9% sensitivity for malignant masses at 1.1 FPs/image.

  12. Knowledge representation and qualitative simulation of salmon redd functioning. Part II: qualitative model of redds.

    PubMed

    Guerrin, F; Dumas, J

    2001-02-01

    This paper describes a qualitative model of the functioning of salmon redds (spawning areas of salmon) and its impact on mortality rates of early stages. For this, we use Qsim, a qualitative simulator, which appeared adequate for representing available qualitative knowledge of freshwater ecology experts (see Part I of this paper). Since the number of relevant variables was relatively large, it appeared necessary to decompose the model into two parts, corresponding to processes occurring at separate time-scales. A qualitative clock allows us to submit the simulation of salmon developmental stages to the calculation of accumulated daily temperatures (degree-days), according to the clock ticks and a water temperature regime set by the user. Therefore, this introduces some way of real-time dating and duration in a purely qualitative model. Simulating both sub-models, either separately or by means of alternate transitions, allows us to generate the evolutions of variables of interest, such as the mortality rates according to two factors (flow of oxygenated water and plugging of gravel interstices near the bed surface), under various scenarios.

  13. A prototype feature system for feature retrieval using relationships

    USGS Publications Warehouse

    Choi, J.; Usery, E.L.

    2009-01-01

    Using a feature data model, geographic phenomena can be represented effectively by integrating space, theme, and time. This paper extends and implements a feature data model that supports query and visualization of geographic features using their non-spatial and temporal relationships. A prototype feature-oriented geographic information system (FOGIS) is then developed and storage of features named Feature Database is designed. Buildings from the U.S. Marine Corps Base, Camp Lejeune, North Carolina and subways in Chicago, Illinois are used to test the developed system. The results of the applications show the strength of the feature data model and the developed system 'FOGIS' when they utilize non-spatial and temporal relationships in order to retrieve and visualize individual features.

  14. 3. VIEW OF DUPLEX (FEATURE 7), FACING NORTH. OFFICE (FEATURE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. VIEW OF DUPLEX (FEATURE 7), FACING NORTH. OFFICE (FEATURE 11) VISIBLE IN BACKGROUND. - Copper Canyon Camp of the International Smelting & Refining Company, Duplex, Copper Canyon, Battle Mountain, Lander County, NV

  15. 1. VIEW OF RESIDENCE (FEATURE 12), FACING SOUTHWEST. DUPLEX (FEATURE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. VIEW OF RESIDENCE (FEATURE 12), FACING SOUTHWEST. DUPLEX (FEATURE 9) IS VISIBLE IN THE BACKGROUND. - Copper Canyon Camp of the International Smelting & Refining Company, Residence, Copper Canyon, Battle Mountain, Lander County, NV

  16. Extending Engineering Practice Research with Shared Qualitative Data

    ERIC Educational Resources Information Center

    Trevelyan, James

    2016-01-01

    Research on engineering practice is scarce and sharing of qualitative research data can reduce the effort required for an aspiring researcher to obtain enough data from engineering workplaces to draw generalizable conclusions, both qualitative and quantitative. This paper describes how a large shareable qualitative data set on engineering…

  17. Curriculum Development for Teaching Qualitative Data Analysis Online

    ERIC Educational Resources Information Center

    Kaczynski, Dan; Kelly, Melissa

    2004-01-01

    This paper explores the unique curriculum design issues involved with the integration of qualitative data analysis software (QDAS) in online instruction of qualitative research. The Qualitative Research III--Analysis course was designed for graduate students and offered in a blended online format using the NVivo[R] software program and the…

  18. The Language of Qualitative Issues. AIR Forum 1982 Paper.

    ERIC Educational Resources Information Center

    Duckwall, Julia M.; Johnson, F. Craig

    The communication of research findings among collegiate institutional researchers is considered in relation to the contribution of qualitative language in general, and catastrophe theory in particular. The qualitative language of catastrophe theory may help reduce the arbitrariness of description, through identification of qualitative features…

  19. Communicating Qualitative Analytical Results Following Grice's Conversational Maxims

    ERIC Educational Resources Information Center

    Chenail, Jan S.; Chenail, Ronald J.

    2011-01-01

    Conducting qualitative research can be seen as a developing communication act through which researchers engage in a variety of conversations. Articulating the results of qualitative data analysis results can be an especially challenging part of this scholarly discussion for qualitative researchers. To help guide investigators through this…

  20. Inclusion of Qualitative Research: Content Analysis of ACA Journals.

    ERIC Educational Resources Information Center

    Portman, Tarrell Awe Agahe

    This paper provides descriptive statistics related to published articles which utilized qualitative methodologies in research studies, as well as conceptual articles pertaining to qualitative research methodologies. The articles examined covered the years 1967-1999. During the 32-year time period, 15 qualitative research articles were published.…