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Nico Karssemeijer - One of the best experts on this subject based on the ideXlab platform.

  • Influence of breast Compression pressure on the performance of population-based mammography screening
    Breast Cancer Research, 2017
    Co-Authors: Katharina Holland, Carla H. Van Gils, Ioannis Sechopoulos, Ritse M. Mann, Gerard J. Den Heeten, Nico Karssemeijer
    Abstract:

    Background In mammography, breast Compression is applied to reduce the thickness of the breast. While it is widely accepted that firm breast Compression is needed to ensure acceptable image quality, guidelines remain vague about how much Compression should be applied during mammogram acquisition. A quantitative parameter indicating the desirable amount of Compression is not available. Consequently, little is known about the relationship between the amount of breast Compression and breast cancer detectability. The purpose of this study is to determine the effect of breast Compression pressure in mammography on breast cancer screening outcomes. Methods We used digital image analysis methods to determine breast volume, percent dense volume, and pressure from 132,776 examinations of 57,179 women participating in the Dutch population-based biennial breast cancer screening program. Pressure was estimated by dividing the Compression force by the area of the contact surface between breast and Compression Paddle. The data was subdivided into quintiles of pressure and the number of screen-detected cancers, interval cancers, false positives, and true negatives were determined for each group. Generalized estimating equations were used to account for correlation between examinations of the same woman and for the effect of breast density and volume when estimating sensitivity, specificity, and other performance measures. Sensitivity was computed using interval cancers occurring between two screening rounds and using interval cancers within 12 months after screening. Pair-wise testing for significant differences was performed. Results Percent dense volume increased with increasing pressure, while breast volume decreased. Sensitivity in quintiles with increasing pressure was 82.0%, 77.1%, 79.8%, 71.1%, and 70.8%. Sensitivity based on interval cancers within 12 months was significantly lower in the highest pressure quintile compared to the third (84.3% vs 93.9%, p  = 0.034). Specificity was lower in the lowest pressure quintile (98.0%) compared to the second, third, and fourth group (98.5%, p  

  • Influence of breast Compression pressure on the performance of population-based mammography screening.
    Breast cancer research : BCR, 2017
    Co-Authors: Katharina Holland, Carla H. Van Gils, Gerard J. Den Heeten, Ioannis Sechopoulos, Ritse M. Mann, Nico Karssemeijer
    Abstract:

    In mammography, breast Compression is applied to reduce the thickness of the breast. While it is widely accepted that firm breast Compression is needed to ensure acceptable image quality, guidelines remain vague about how much Compression should be applied during mammogram acquisition. A quantitative parameter indicating the desirable amount of Compression is not available. Consequently, little is known about the relationship between the amount of breast Compression and breast cancer detectability. The purpose of this study is to determine the effect of breast Compression pressure in mammography on breast cancer screening outcomes. We used digital image analysis methods to determine breast volume, percent dense volume, and pressure from 132,776 examinations of 57,179 women participating in the Dutch population-based biennial breast cancer screening program. Pressure was estimated by dividing the Compression force by the area of the contact surface between breast and Compression Paddle. The data was subdivided into quintiles of pressure and the number of screen-detected cancers, interval cancers, false positives, and true negatives were determined for each group. Generalized estimating equations were used to account for correlation between examinations of the same woman and for the effect of breast density and volume when estimating sensitivity, specificity, and other performance measures. Sensitivity was computed using interval cancers occurring between two screening rounds and using interval cancers within 12 months after screening. Pair-wise testing for significant differences was performed. Percent dense volume increased with increasing pressure, while breast volume decreased. Sensitivity in quintiles with increasing pressure was 82.0%, 77.1%, 79.8%, 71.1%, and 70.8%. Sensitivity based on interval cancers within 12 months was significantly lower in the highest pressure quintile compared to the third (84.3% vs 93.9%, p = 0.034). Specificity was lower in the lowest pressure quintile (98.0%) compared to the second, third, and fourth group (98.5%, p < 0.005). Specificity of the fifth quintile was 98.4%. Results suggest that if too much pressure is applied during mammography this may reduce sensitivity. In contrast, if pressure is low this may decrease specificity.

  • Optimization of volumetric breast density estimation in digital mammograms.
    Physics in Medicine and Biology, 2017
    Co-Authors: Katharina Holland, Ritse M. Mann, Albert Gubern-mérida, Nico Karssemeijer
    Abstract:

    Fibroglandular tissue volume and percent density can be estimated in unprocessed mammograms using a physics-based method, which relies on an internal reference value representing the projection of fat only. However, pixels representing fat only may not be present in dense breasts, causing an underestimation of density measurements. In this work, we investigate alternative approaches for obtaining a tissue reference value to improve density estimations, particularly in dense breasts. Two of three investigated reference values (F1, F2) are percentiles of the pixel value distribution in the breast interior (the contact area of breast and Compression Paddle). F1 is determined in a small breast interior, which minimizes the risk that peripheral pixels are included in the measurement at the cost of increasing the chance that no proper reference can be found. F2 is obtained using a larger breast interior. The new approach which is developed for very dense breasts does not require the presence of a fatty tissue region. As reference region we select the densest region in the mammogram and assume that this represents a projection of entirely dense tissue embedded between the subcutaneous fatty tissue layers. By measuring the thickness of the fat layers a reference (F3) can be computed. To obtain accurate breast density estimates irrespective of breast composition we investigated a combination of the results of the three reference values. We collected 202 pairs of MRI's and digital mammograms from 119 women. We compared the percent dense volume estimates based on both modalities and calculated Pearson's correlation coefficients. With the references F1-F3 we found respectively a correlation of [Formula: see text], [Formula: see text] and [Formula: see text]. Best results were obtained with the combination of the density estimations ([Formula: see text]). Results show that better volumetric density estimates can be obtained with the hybrid method, in particular for dense breasts, when algorithms are combined to obtain a fatty tissue reference value depending on breast composition.

  • Digital Mammography / IWDM - Performance of Breast Cancer Screening Depends on Mammographic Compression
    Breast Imaging, 2016
    Co-Authors: Katharina Holland, Gerard J. Den Heeten, Ioannis Sechopoulos, Ritse M. Mann, Nico Karssemeijer
    Abstract:

    During mammographic acquisition, the breast is compressed between the breast support plate and the Compression Paddle to improve image quality and reduce dose, among other reasons. The applied force, which is measured by the imaging device, varies substantially, due to local guidelines, positioning, and breast size. Force measurements may not be very relevant though, because the amount of Compression will be related to pressure rather than force. With modern image analysis techniques, the contact surface of the breast under Compression can be determined and pressure can be computed retrospectively. In this study, we investigate if there is a relation between pressure applied to the breast during Compression and screening performance. In a series of 113,464 screening exams from the Dutch breast cancer screening program we computed the Compression pressure applied in the MLO projections of the right and left breasts. The exams were binned into five groups of increasing applied pressure, in such a way that each group contains 20i¾?% of the exams. Thresholds were 7.68, 9.18, 10.71 and 12.81i¾?kPa. Screening performance measures were determined for each group. Differences across the groups were investigated with a Pearson's Chi Square test. It was found that PPV and the cancer detection rate vary significantly within the five groups pi¾?=i¾?0.001 and pi¾?=i¾?0.011 respectively. The PPV was 25.4, 31.2, 32.7, 25.8 and 22.0 for the five groups with increasing pressure. The recall rate, false positive rate and specificity were not statistically significant from the expectation p-values: 0.858, 0.088 and 0.094 respectively. Even though differences are not significant, there is a trend that the groups with a moderate pressure have a better performance compared to the first and last category. The results suggest that high pressure reduces detectability of breast cancer. The best screening results were found in the groups with a moderate pressure.

  • Effect of Compression Paddle tilt correction on volumetric breast density estimation.
    Physics in Medicine and Biology, 2012
    Co-Authors: Michiel Kallenberg, Carla H. Van Gils, Mariëtte Lokate, Gerard J. Den Heeten, Nico Karssemeijer
    Abstract:

    For the acquisition of a mammogram, a breast is compressed between a Compression Paddle and a support table. When Compression is applied with a flexible Compression Paddle, the upper plate may be tilted, which results in variation in breast thickness from the chest wall to the breast margin. Paddle tilt has been recognized as a major problem in volumetric breast density estimation methods. In previous work, we developed a fully automatic method to correct the image for the effect of Compression Paddle tilt. In this study, we investigated in three experiments the effect of Paddle tilt and its correction on volumetric breast density estimation. Results showed that Paddle tilt considerably affected accuracy of volumetric breast density estimation, but that effect could be reduced by tilt correction. By applying tilt correction, a significant increase in correspondence between mammographic density estimates and measurements on MRI was established. We argue that in volumetric breast density estimation, tilt correction is both feasible and essential when mammographic images are acquired with a flexible Compression Paddle.

Ioannis Sechopoulos - One of the best experts on this subject based on the ideXlab platform.

  • Influence of breast Compression pressure on the performance of population-based mammography screening
    Breast Cancer Research, 2017
    Co-Authors: Katharina Holland, Carla H. Van Gils, Ioannis Sechopoulos, Ritse M. Mann, Gerard J. Den Heeten, Nico Karssemeijer
    Abstract:

    Background In mammography, breast Compression is applied to reduce the thickness of the breast. While it is widely accepted that firm breast Compression is needed to ensure acceptable image quality, guidelines remain vague about how much Compression should be applied during mammogram acquisition. A quantitative parameter indicating the desirable amount of Compression is not available. Consequently, little is known about the relationship between the amount of breast Compression and breast cancer detectability. The purpose of this study is to determine the effect of breast Compression pressure in mammography on breast cancer screening outcomes. Methods We used digital image analysis methods to determine breast volume, percent dense volume, and pressure from 132,776 examinations of 57,179 women participating in the Dutch population-based biennial breast cancer screening program. Pressure was estimated by dividing the Compression force by the area of the contact surface between breast and Compression Paddle. The data was subdivided into quintiles of pressure and the number of screen-detected cancers, interval cancers, false positives, and true negatives were determined for each group. Generalized estimating equations were used to account for correlation between examinations of the same woman and for the effect of breast density and volume when estimating sensitivity, specificity, and other performance measures. Sensitivity was computed using interval cancers occurring between two screening rounds and using interval cancers within 12 months after screening. Pair-wise testing for significant differences was performed. Results Percent dense volume increased with increasing pressure, while breast volume decreased. Sensitivity in quintiles with increasing pressure was 82.0%, 77.1%, 79.8%, 71.1%, and 70.8%. Sensitivity based on interval cancers within 12 months was significantly lower in the highest pressure quintile compared to the third (84.3% vs 93.9%, p  = 0.034). Specificity was lower in the lowest pressure quintile (98.0%) compared to the second, third, and fourth group (98.5%, p  

  • Influence of breast Compression pressure on the performance of population-based mammography screening.
    Breast cancer research : BCR, 2017
    Co-Authors: Katharina Holland, Carla H. Van Gils, Gerard J. Den Heeten, Ioannis Sechopoulos, Ritse M. Mann, Nico Karssemeijer
    Abstract:

    In mammography, breast Compression is applied to reduce the thickness of the breast. While it is widely accepted that firm breast Compression is needed to ensure acceptable image quality, guidelines remain vague about how much Compression should be applied during mammogram acquisition. A quantitative parameter indicating the desirable amount of Compression is not available. Consequently, little is known about the relationship between the amount of breast Compression and breast cancer detectability. The purpose of this study is to determine the effect of breast Compression pressure in mammography on breast cancer screening outcomes. We used digital image analysis methods to determine breast volume, percent dense volume, and pressure from 132,776 examinations of 57,179 women participating in the Dutch population-based biennial breast cancer screening program. Pressure was estimated by dividing the Compression force by the area of the contact surface between breast and Compression Paddle. The data was subdivided into quintiles of pressure and the number of screen-detected cancers, interval cancers, false positives, and true negatives were determined for each group. Generalized estimating equations were used to account for correlation between examinations of the same woman and for the effect of breast density and volume when estimating sensitivity, specificity, and other performance measures. Sensitivity was computed using interval cancers occurring between two screening rounds and using interval cancers within 12 months after screening. Pair-wise testing for significant differences was performed. Percent dense volume increased with increasing pressure, while breast volume decreased. Sensitivity in quintiles with increasing pressure was 82.0%, 77.1%, 79.8%, 71.1%, and 70.8%. Sensitivity based on interval cancers within 12 months was significantly lower in the highest pressure quintile compared to the third (84.3% vs 93.9%, p = 0.034). Specificity was lower in the lowest pressure quintile (98.0%) compared to the second, third, and fourth group (98.5%, p < 0.005). Specificity of the fifth quintile was 98.4%. Results suggest that if too much pressure is applied during mammography this may reduce sensitivity. In contrast, if pressure is low this may decrease specificity.

  • The compressed breast during mammography and breast tomosynthesis: in vivo shape characterization and modeling
    Physics in Medicine & Biology, 2017
    Co-Authors: Alejandro Rodriguez-ruiz, Greeshma A. Agasthya, Ioannis Sechopoulos
    Abstract:

    To characterize and develop a patient-based 3D model of the compressed breast undergoing mammography and breast tomosynthesis. During this IRB-approved, HIPAA-compliant study, 50 women were recruited to undergo 3D breast surface imaging with structured light (SL) during breast Compression, along with simultaneous acquisition of a tomosynthesis image. A pair of SL systems were used to acquire 3D surface images by projecting 24 different patterns onto the compressed breast and capturing their reflection off the breast surface in approximately 12-16 s. The 3D surface was characterized and modeled via principal component analysis. The resulting surface model was combined with a previously developed 2D model of projected compressed breast shapes to generate a full 3D model. Data from ten patients were discarded due to technical problems during image acquisition. The maximum breast thickness (found at the chest-wall) had an average value of 56 mm, and decreased 13% towards the nipple (breast tilt angle of 5.2 degrees ). The portion of the breast not in contact with the Compression Paddle or the support table extended on average 17 mm, 18% of the chest-wall to nipple distance. The outermost point along the breast surface lies below the midline of the total thickness. A complete 3D model of compressed breast shapes was created and implemented as a software application available for download, capable of generating new random realistic 3D shapes of breasts undergoing Compression. Accurate characterization and modeling of the breast curvature and shape was achieved and will be used for various image processing and clinical tasks.

  • The compressed breast during mammography and breast tomosynthesis: in vivo shape characterization and modeling
    Physics in medicine and biology, 2017
    Co-Authors: Alejandro Rodriguez-ruiz, Greeshma A. Agasthya, Ioannis Sechopoulos
    Abstract:

    To characterize and develop a patient-based 3D model of the compressed breast undergoing mammography and breast tomosynthesis. During this IRB-approved, HIPAA-compliant study, 50 women were recruited to undergo 3D breast surface imaging with structured light (SL) during breast Compression, along with simultaneous acquisition of a tomosynthesis image. A pair of SL systems were used to acquire 3D surface images by projecting 24 different patterns onto the compressed breast and capturing their reflection off the breast surface in approximately 12-16 s. The 3D surface was characterized and modeled via principal component analysis. The resulting surface model was combined with a previously developed 2D model of projected compressed breast shapes to generate a full 3D model. Data from ten patients were discarded due to technical problems during image acquisition. The maximum breast thickness (found at the chest-wall) had an average value of 56 mm, and decreased 13% towards the nipple (breast tilt angle of 5.2°). The portion of the breast not in contact with the Compression Paddle or the support table extended on average 17 mm, 18% of the chest-wall to nipple distance. The outermost point along the breast surface lies below the midline of the total thickness. A complete 3D model of compressed breast shapes was created and implemented as a software application available for download, capable of generating new random realistic 3D shapes of breasts undergoing Compression. Accurate characterization and modeling of the breast curvature and shape was achieved and will be used for various image processing and clinical tasks.

  • Digital Mammography / IWDM - Performance of Breast Cancer Screening Depends on Mammographic Compression
    Breast Imaging, 2016
    Co-Authors: Katharina Holland, Gerard J. Den Heeten, Ioannis Sechopoulos, Ritse M. Mann, Nico Karssemeijer
    Abstract:

    During mammographic acquisition, the breast is compressed between the breast support plate and the Compression Paddle to improve image quality and reduce dose, among other reasons. The applied force, which is measured by the imaging device, varies substantially, due to local guidelines, positioning, and breast size. Force measurements may not be very relevant though, because the amount of Compression will be related to pressure rather than force. With modern image analysis techniques, the contact surface of the breast under Compression can be determined and pressure can be computed retrospectively. In this study, we investigate if there is a relation between pressure applied to the breast during Compression and screening performance. In a series of 113,464 screening exams from the Dutch breast cancer screening program we computed the Compression pressure applied in the MLO projections of the right and left breasts. The exams were binned into five groups of increasing applied pressure, in such a way that each group contains 20i¾?% of the exams. Thresholds were 7.68, 9.18, 10.71 and 12.81i¾?kPa. Screening performance measures were determined for each group. Differences across the groups were investigated with a Pearson's Chi Square test. It was found that PPV and the cancer detection rate vary significantly within the five groups pi¾?=i¾?0.001 and pi¾?=i¾?0.011 respectively. The PPV was 25.4, 31.2, 32.7, 25.8 and 22.0 for the five groups with increasing pressure. The recall rate, false positive rate and specificity were not statistically significant from the expectation p-values: 0.858, 0.088 and 0.094 respectively. Even though differences are not significant, there is a trend that the groups with a moderate pressure have a better performance compared to the first and last category. The results suggest that high pressure reduces detectability of breast cancer. The best screening results were found in the groups with a moderate pressure.

Gerard J. Den Heeten - One of the best experts on this subject based on the ideXlab platform.

  • Influence of breast Compression pressure on the performance of population-based mammography screening.
    Breast cancer research : BCR, 2017
    Co-Authors: Katharina Holland, Carla H. Van Gils, Gerard J. Den Heeten, Ioannis Sechopoulos, Ritse M. Mann, Nico Karssemeijer
    Abstract:

    In mammography, breast Compression is applied to reduce the thickness of the breast. While it is widely accepted that firm breast Compression is needed to ensure acceptable image quality, guidelines remain vague about how much Compression should be applied during mammogram acquisition. A quantitative parameter indicating the desirable amount of Compression is not available. Consequently, little is known about the relationship between the amount of breast Compression and breast cancer detectability. The purpose of this study is to determine the effect of breast Compression pressure in mammography on breast cancer screening outcomes. We used digital image analysis methods to determine breast volume, percent dense volume, and pressure from 132,776 examinations of 57,179 women participating in the Dutch population-based biennial breast cancer screening program. Pressure was estimated by dividing the Compression force by the area of the contact surface between breast and Compression Paddle. The data was subdivided into quintiles of pressure and the number of screen-detected cancers, interval cancers, false positives, and true negatives were determined for each group. Generalized estimating equations were used to account for correlation between examinations of the same woman and for the effect of breast density and volume when estimating sensitivity, specificity, and other performance measures. Sensitivity was computed using interval cancers occurring between two screening rounds and using interval cancers within 12 months after screening. Pair-wise testing for significant differences was performed. Percent dense volume increased with increasing pressure, while breast volume decreased. Sensitivity in quintiles with increasing pressure was 82.0%, 77.1%, 79.8%, 71.1%, and 70.8%. Sensitivity based on interval cancers within 12 months was significantly lower in the highest pressure quintile compared to the third (84.3% vs 93.9%, p = 0.034). Specificity was lower in the lowest pressure quintile (98.0%) compared to the second, third, and fourth group (98.5%, p < 0.005). Specificity of the fifth quintile was 98.4%. Results suggest that if too much pressure is applied during mammography this may reduce sensitivity. In contrast, if pressure is low this may decrease specificity.

  • Technical Note: Validation of two methods to determine contact area between breast and Compression Paddle in mammography
    Medical Physics, 2017
    Co-Authors: Woutjan Branderhorst, Gerard J. Den Heeten, Jerry E. De Groot, Monique G.j.t.b. Van Lier, Ralph Highnam, Cornelis A. Grimbergen
    Abstract:

    Purpose To assess the accuracy of two methods of determining the contact area between the Compression Paddle and the breast in mammography. An accurate method to determine the contact area is essential to accurately calculate the average Compression pressure applied by the Paddle. Methods For a set of 300 breast Compressions, we measured the contact areas between breast and Paddle, both capacitively using a transparent foil with indium-tin-oxide (ITO) coating attached to the Paddle, and retrospectively from the obtained mammograms using image processing software (Volpara Enterprise, algorithm version 1.5.2). A gold standard was obtained from video images of the compressed breast. During each Compression, the breast was illuminated from the sides in order to create a dark shadow on the video image where the breast was in contact with the Compression Paddle. We manually segmented the shadows captured at the time of X-ray exposure and measured their areas. Results We found a strong correlation between the manual segmentations and the capacitive measurements (r = 0.989, 95% CI [0.987, 0.992]) and between the manual segmentations and the image processing software (r = 0.978, 95% CI [0.972, 0.982]). Bland–Altman analysis showed a bias of -0.0038 dm2 for the capacitive measurement (SD 0.0658, 95% limits of agreement [-0.1329, 0.1252]) and -0.0035 dm2 for the image processing software (SD 0.0962, 95% limits of agreement [-0.1921, 0.1850]). Conclusions The size of the contact area between the Paddle and the breast can be determined accurately and precisely, both in real-time using the capacitive method, and retrospectively using image processing software. This result is beneficial for scientific research, data analysis and quality control systems that depend on one of these two methods for determining the average pressure on the breast during mammographic Compression. This article is protected by copyright. All rights reserved.

  • Technical Note: Validation of two methods to determine contact area between breast and Compression Paddle in mammography
    Medical physics, 2017
    Co-Authors: Woutjan Branderhorst, Gerard J. Den Heeten, Jerry E. De Groot, Monique G.j.t.b. Van Lier, Ralph Highnam, Cornelis A. Grimbergen
    Abstract:

    To assess the accuracy of two methods of determining the contact area between the Compression Paddle and the breast in mammography. An accurate method to determine the contact area is essential to accurately calculate the average Compression pressure applied by the Paddle. For a set of 300 breast Compressions, we measured the contact areas between breast and Paddle, both capacitively using a transparent foil with indium-tin-oxide (ITO) coating attached to the Paddle, and retrospectively from the obtained mammograms using image processing software (Volpara Enterprise, algorithm version 1.5.2). A gold standard was obtained from video images of the compressed breast. During each Compression, the breast was illuminated from the sides in order to create a dark shadow on the video image where the breast was in contact with the Compression Paddle. We manually segmented the shadows captured at the time of x-ray exposure and measured their areas. We found a strong correlation between the manual segmentations and the capacitive measurements [r = 0.989, 95% CI (0.987, 0.992)] and between the manual segmentations and the image processing software [r = 0.978, 95% CI (0.972, 0.982)]. Bland-Altman analysis showed a bias of -0.0038 dm2 for the capacitive measurement (SD 0.0658, 95% limits of agreement [-0.1329, 0.1252]) and -0.0035 dm2 for the image processing software [SD 0.0962, 95% limits of agreement (-0.1921, 0.1850)]. The size of the contact area between the Paddle and the breast can be determined accurately and precisely, both in real-time using the capacitive method, and retrospectively using image processing software. This result is beneficial for scientific research, data analysis and quality control systems that depend on one of these two methods for determining the average pressure on the breast during mammographic Compression. © 2017 Sigmascreening B.V. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  • Digital Mammography / IWDM - Performance of Breast Cancer Screening Depends on Mammographic Compression
    Breast Imaging, 2016
    Co-Authors: Katharina Holland, Gerard J. Den Heeten, Ioannis Sechopoulos, Ritse M. Mann, Nico Karssemeijer
    Abstract:

    During mammographic acquisition, the breast is compressed between the breast support plate and the Compression Paddle to improve image quality and reduce dose, among other reasons. The applied force, which is measured by the imaging device, varies substantially, due to local guidelines, positioning, and breast size. Force measurements may not be very relevant though, because the amount of Compression will be related to pressure rather than force. With modern image analysis techniques, the contact surface of the breast under Compression can be determined and pressure can be computed retrospectively. In this study, we investigate if there is a relation between pressure applied to the breast during Compression and screening performance. In a series of 113,464 screening exams from the Dutch breast cancer screening program we computed the Compression pressure applied in the MLO projections of the right and left breasts. The exams were binned into five groups of increasing applied pressure, in such a way that each group contains 20i¾?% of the exams. Thresholds were 7.68, 9.18, 10.71 and 12.81i¾?kPa. Screening performance measures were determined for each group. Differences across the groups were investigated with a Pearson's Chi Square test. It was found that PPV and the cancer detection rate vary significantly within the five groups pi¾?=i¾?0.001 and pi¾?=i¾?0.011 respectively. The PPV was 25.4, 31.2, 32.7, 25.8 and 22.0 for the five groups with increasing pressure. The recall rate, false positive rate and specificity were not statistically significant from the expectation p-values: 0.858, 0.088 and 0.094 respectively. Even though differences are not significant, there is a trend that the groups with a moderate pressure have a better performance compared to the first and last category. The results suggest that high pressure reduces detectability of breast cancer. The best screening results were found in the groups with a moderate pressure.

  • Comparison of a flexible versus a rigid breast Compression Paddle: pain experience, projected breast area, radiation dose and technical image quality
    European Radiology, 2015
    Co-Authors: Mireille J. M. Broeders, Marloes Voorde, Wouter J. H. Veldkamp, Ruben E. Engen, Cary Landsveld – Verhoeven, Machteld N. L. ’t Jong – Gunneman, Jos Win, Kitty Droogh-de Greve, Ellen Paap, Gerard J. Den Heeten
    Abstract:

    Purpose To compare pain, projected breast area, radiation dose and image quality between flexible (FP) and rigid (RP) breast Compression Paddles. Methods The study was conducted in a Dutch mammographic screening unit (288 women). To compare both Paddles one additional image with RP was made, consisting of either a mediolateral-oblique (MLO) or craniocaudal-view (CC). Pain experience was scored using the Numeric Rating Scale (NRS). Projected breast area was estimated using computer software. Radiation dose was estimated using the model by Dance. Image quality was reviewed by three radiologists and three radiographers. Results There was no difference in pain experience between both Paddles (mean difference NRS: 0.08 ± 0.08, p  = 0.32). Mean radiation dose was 4.5 % lower with FP (0.09 ± 0.01 p  = 0.00). On MLO-images, the projected breast area was 0.79 % larger with FP. Paired evaluation of image quality indicated that FP removed fibroglandular tissue from the image area and reduced contrast in the clinically relevant retroglandular area at chest wall side. Conclusions Although FP performed slightly better in the projected breast area, it moved breast tissue from the image area at chest wall side. RP showed better contrast, especially in the retroglandular area. We therefore recommend the use of RP for standard MLO and CC views. Key points • Pain experience showed no difference between flexible and rigid breast Compression Paddles. • Flexible Paddles do not depict clinically relevant retroglandular areas as well. • Flexible Paddles move breast tissue from image area at the chest wall side. • Rigid Paddles depict more breast tissue and shows better contrast. • Rigid breast Compression Paddles are recommended for standard mediolateral-oblique and craniocaudal views.

Martin J. Yaffe - One of the best experts on this subject based on the ideXlab platform.

  • Mean glandular dose coefficients (D(g)N) for x-ray spectra used in contemporary breast imaging systems.
    Physics in Medicine and Biology, 2015
    Co-Authors: Anita Nosratieh, Martin J. Yaffe, Andrew M. Hernandez, Sam Z. Shen, J. Anthony Seibert, John M. Boone
    Abstract:

    To develop tables of normalized glandular dose coefficients D(g)N for a range of anode-filter combinations and tube voltages used in contemporary breast imaging systems. Previously published mono-energetic D(g)N values were used with various spectra to mathematically compute D(g)N coefficients. The tungsten anode spectra from TASMICS were used; molybdenum and rhodium anode-spectra were generated using MCNPX Monte Carlo code. The spectra were filtered with various thicknesses of Al, Rh, Mo or Cu. An initial half value layer (HVL) calculation was made using the anode and filter material. A range of the HVL values was produced with the addition of small thicknesses of polymethyl methacrylate (PMMA) as a surrogate for the breast Compression Paddle, to produce a range of HVL values at each tube voltage. Using a spectral weighting method, D(g)N coefficients for the generated spectra were calculated for breast glandular densities of 0%, 12.5%, 25%, 37.5%, 50% and 100% for a range of compressed breast thicknesses from 3 to 8 cm. Eleven tables of normalized glandular dose (D(g)N) coefficients were produced for the following anode/filter combinations: W + 50 μm Ag, W + 500 μm Al, W + 700 μm Al, W + 200 μm Cu, W + 300 μm Cu, W + 50 μm Rh, Mo + 400 μm Cu, Mo + 30 μm Mo, Mo + 25 μm Rh, Rh + 400 μm Cu and Rh + 25 μm Rh. Where possible, these results were compared to previously published D(g)N values and were found to be on average less than 2% different than previously reported values.Over 200 pages of D(g)N coefficients were computed for modeled x-ray system spectra that are used in a number of new breast imaging applications. The reported values were found to be in excellent agreement when compared to published values.

  • The relationship between anatomic noise and volumetric breast density for digital mammography
    Medical Physics, 2012
    Co-Authors: James G. Mainprize, Albert H. Tyson, Martin J. Yaffe
    Abstract:

    Purpose: The appearance of parenchymal/stromal patterns in mammography have been characterized as having a Wiener power spectrum with an inverse power-law shape described by the exponential parameter,β. The amount of fibroglandular tissue, which can be quantified in terms of volumetric breast density (VBD), influences the texture and appearance of the patterns formed in a mammogram. Here, a large study is performed to investigate the variations in β in a clinical population and to indicate the relationship between β and breast density. Methods: From a set of 2686 cranio-caudal normal screening mammograms, the parameterβ was extracted from log-log fits to the Wiener spectrum over the range 0.15–1 mm−1. The Wiener spectrum was calculated from regions of interest in the Compression Paddle contact region of the breast. An in-house computer program, Cumulus V, was used to extract the volumetric breast density and identify the Compression Paddle contact regions of the breast. The Wiener spectra were calculated with and without modulation transfer function (MTF) correction to determine the impact of VBD on the intrinsic anatomic noise. Results: The mean volumetric breast density was 25.5% (±12.6%) over all images. The meanβ following a MTF correction which decreased the β slightly (≈−0.08) was found to be 2.87. Varying the maximum of the spatial frequency range of the fits from 0.7 to 1.0, 1.25 or 1.5 mm−1 showing small decreases in the result, although the effect of the quantum noise power component on reducing β was clearly observed at 1.5 mm−1. Conclusions: The texture parameter,β, was found to increase with VBD at low volumetric breast densities with an apparent leveling off at higher densities. The relationship between β and VBD measured here can be used to create probabilistic models for computer simulations of detectability. As breast density is a known risk predictor for breast cancer, the correlation between β and VBD suggests that β may provide predictive information and this will be investigated in the future.

  • The relationship between anatomic noise and volumetric breast density for digital mammography
    Medical physics, 2012
    Co-Authors: James G. Mainprize, Albert H. Tyson, Martin J. Yaffe
    Abstract:

    The appearance of parenchymal∕stromal patterns in mammography have been characterized as having a Wiener power spectrum with an inverse power-law shape described by the exponential parameter, β. The amount of fibroglandular tissue, which can be quantified in terms of volumetric breast density (VBD), influences the texture and appearance of the patterns formed in a mammogram. Here, a large study is performed to investigate the variations in β in a clinical population and to indicate the relationship between β and breast density. From a set of 2686 cranio-caudal normal screening mammograms, the parameter β was extracted from log-log fits to the Wiener spectrum over the range 0.15-1 mm(-1). The Wiener spectrum was calculated from regions of interest in the Compression Paddle contact region of the breast. An in-house computer program, Cumulus V, was used to extract the volumetric breast density and identify the Compression Paddle contact regions of the breast. The Wiener spectra were calculated with and without modulation transfer function (MTF) correction to determine the impact of VBD on the intrinsic anatomic noise. The mean volumetric breast density was 25.5% (±12.6%) over all images. The mean β following a MTF correction which decreased the β slightly (≈-0.08) was found to be 2.87. Varying the maximum of the spatial frequency range of the fits from 0.7 to 1.0, 1.25 or 1.5 mm(-1) showing small decreases in the result, although the effect of the quantum noise power component on reducing β was clearly observed at 1.5 mm(-1). The texture parameter, β, was found to increase with VBD at low volumetric breast densities with an apparent leveling off at higher densities. The relationship between β and VBD measured here can be used to create probabilistic models for computer simulations of detectability. As breast density is a known risk predictor for breast cancer, the correlation between β and VBD suggests that β may provide predictive information and this will be investigated in the future.

  • Digital Mammography / IWDM - Development of a peripheral thickness estimation method for volumetric breast density measurements in mammography using a 3d finite element breast model
    Digital Mammography, 2010
    Co-Authors: Olivier Alonzo-proulx, James G. Mainprize, Nathan J. Packard, John M. Boone, Adil Al-mayah, Kristy K. Brock, Martin J. Yaffe
    Abstract:

    A method was developed to determine the area in a mammogram where the breast is not in contact with the Compression Paddle (the periphery), and to predict the breast thickness in that peripheral region The periphery is determined by evaluating the variation of the signal intensity along radial lines, and the peripheral thickness is modeled assuming the breast has a semi-circular shape The method was tested on 26 simulated mammograms for which the volumetric information was available The mammograms were obtained using CT data that were deformed to simulate mammographic Compression and then projected using a physical model The method predicted the thickness in the periphery to within 3.3 mm of the actual value and the volumetric breast density within 4.3 percentage points The method was also tested on 209 digital mammograms, and on average it was estimated that thickness errors occurred on 9% of the breast image, and the average absolute thickness error on those points was estimated to be approximately 2.0 mm in the periphery and central region of the breast but as large as 10.5 mm in the extreme periphery where the thickness is small.

  • measurement of compressed breast thickness by optical stereoscopic photogrammetry
    Medical Physics, 2009
    Co-Authors: Albert H. Tyson, Gordon E. Mawdsley, Martin J. Yaffe
    Abstract:

    The determination of volumetric breast density (VBD) from mammograms requires accurate knowledge of the thickness of the compressed breast. In attempting to accurately determine VBD from images obtained on conventional mammography systems, the authors found that the thickness reported by a number of mammography systems in the field varied by as much as 15 mm when compressing the same breast or phantom. In order to evaluate the behavior of mammographic Compression systems and to be able to predict the thickness at different locations in the breast on patients, they have developed a method for measuring the local thickness of the breast at all points of contact with the Compression Paddle using optical stereoscopic photogrammetry. On both flat (solid) and compressible phantoms, the measurements were accurate to better than 1 mm with a precision of 0.2 mm. In a pilot study, this method was used to measure thickness on 108 volunteers who were undergoing mammography examination. This measurement tool will allow us to characterize Paddle surface deformations, deflections and calibration offsets for mammographic units.

Mitchell M. Goodsitt - One of the best experts on this subject based on the ideXlab platform.

  • Acoustic performance of mesh Compression Paddles for a multimodality breast imaging system.
    Ultrasound in Medicine and Biology, 2014
    Co-Authors: Gerald L. Lecarpentier, Mitchell M. Goodsitt, Sacha A.m. Verweij, Jie Li, Frederic Padilla, Paul L. Carson
    Abstract:

    Abstract A system incorporating automated 3-D ultrasound and digital X-ray tomosynthesis is being developed for improved breast lesion detection and characterization. The goal of this work is to develop and test candidates for a dual-modality mesh Compression Paddle. A Computerized Imaging Reference Systems (Norfork, VA, USA) ultrasound phantom with tilted low-contrast cylindrical objects was used. Polyester mesh fabrics (1- and 2-mm spacing), a high-density polyethylene filament grid (Dyneema, DSM Dyneema, Stanley, NC, USA) and a solid polymethylpentene (TPX; Mitsui Plastics, Inc., White Plains, NY) Paddle were compared with no overlying structures using a GE Logic 9 with M12L transducer. A viscous gel provided coupling. The phantom was scanned 10 times over 9 cm for each configuration. Image volumes were analyzed for signal strength, contrast and contrast-to-noise ratio. X-ray tests confirmed X-ray transparency for all materials. By all measures, both mesh fabrics outperformed TPX and Dyneema, and there were essentially no differences between 2-mm mesh and unobstructed configurations.

  • New Compression Paddle for wire localization in mammography.
    Academic Radiology, 2010
    Co-Authors: Caroline E. Blane, Mitchell M. Goodsitt, Jeffrey C. Grimm, James Pavlik, Daniel J. March, Jonathon T. Ong, Lisa Blacklaw, Mark A. Helvie
    Abstract:

    Rationale and Objectives Current wire localization Compression Paddles provide a limited access window with no Compression in this window. We describe a new Compression Paddle that addresses these issues and report on preliminary patient testing. Materials and Methods Four mechanical engineering students collaborated with a medical physicist, a radiographer, and two radiologists. Several concept designs were developed, one of which used a mesh surface. This went on to prototype development. After phantom testing, internal review board approval, US Food and Drug Administration waiver for nonsignificant risk device, and Medicare Part A exemption were obtained, the device was used in 10 patients going to wire localization for medical indications. Informed consent was obtained and a range of breast size was included. Wires were positioned from superior, lateral, and medial approach. Results A total of 10 wires were successfully positioned in nine patients. The one technical failure was due to inadequate access to the axillary region because of the single prototype size. The grid system provided accurate localization of suspicious findings. The mesh was not visible in digital mammograms so there was no interference. Conclusion The new Paddle improves on currently available models. Advantages included lack of visual (on imaging) and technical interference from the Compression mesh, and Compression of the active window allowed localization of subtle findings. The large active area facilitated multiple wire placements within a single window. All localizations were easily performed on the initial image because of the large active window, obviating the need for acquisition of additional images and the associated additional radiation.

  • automated ultrasound scanning on a dual modality breast imaging system coverage and motion issues and solutions
    Journal of Ultrasound in Medicine, 2007
    Co-Authors: Sumedha P Sinha, Gerald L. Lecarpentier, Mitchell M. Goodsitt, Kai Erik Thomenius, Marilyn A. Roubidoux, Rebecca C. Booi, Christine R Lashbrook, Carl L Chalek, Paul L. Carson
    Abstract:

    Objective. We are developing an automated ultrasound imaging-mammography system wherein a digital mammography unit has been augmented with a motorized ultrasound transducer carriage above a special Compression Paddle. Challenges of this system are acquiring complete coverage of the breast and minimizing motion. We assessed these problems and investigated methods to increase coverage and stabilize the compressed breast. Methods. Visual tracings of the breast-to-Paddle contact area and breast periphery were made for 10 patients to estimate coverage area. Various motion artifacts were evaluated in 6 patients. Nine materials were tested for coupling the Paddle to the breast. Fourteen substances were tested for coupling the transducer to the Paddle in lateral-to-medial and medial-to-lateral views and filling the gap between the peripheral breast and Paddle. In-house image registration software was used to register adjacent ultrasound sweeps. Results. The average breast contact area was 56%. The average percentage of the peripheral air gap filled with ultrasound gel was 61%. Shallow patient breathing proved equivalent to breath holding, whereas speech and sudden breathing caused unacceptable artifacts. An adhesive spray that preserves image quality was found to be best for coupling the breast to the Paddle and minimizing motion. A highly viscous ultrasound gel proved most effective for coupling the transducer to the Paddle for lateral-to-medial and medial-to-lateral views and for edge fill-in. Conclusions. The challenges of automated ultrasound scanning in a multimodality breast imaging system have been addressed by developing methods to fill in peripheral gaps, minimize patient motion, and register and reconstruct multisweep ultrasound image volumes.

  • An observer study comparing spot imaging regions selected by radiologists and a computer for an automated stereo spot mammography technique
    Medical Physics, 2004
    Co-Authors: Mitchell M. Goodsitt, Mark A. Helvie, Marilyn A. Roubidoux, Heang-ping Chan, Justin T. Lydick, Chaitanya R. Gandra, Nelson G. Chen, Janet E. Bailey, Chintana Paramagul, Caroline E. Blane
    Abstract:

    We are developing an automated stereo spot mammography technique for improved imaging of suspicious dense regions within digital mammograms. The technique entails the acquisition of a full-field digital mammogram, automated detection of a suspicious dense region within that mammogram by a computer aided detection (CAD) program, and acquisition of a stereo pair of images with automated collimation to the suspicious region. The latter stereo spot image is obtained within seconds of the original full-field mammogram, without releasing the Compression Paddle. The spot image is viewed on a stereo video display. A critical element of this technique is the automated detection of suspicious regions for spot imaging. We performed an observer study to compare the suspicious regions selected by radiologists with those selected by a CAD program developed at the University of Michigan. True regions of interest (TROIs) were separately determined by one of the radiologists who reviewed the original mammograms, biopsy images, and histology results. We compared the radiologist and computer-selected regions of interest (ROIs) to the TROIs. Both the radiologists and the computer were allowed to select up to 3 regions in each of 200 images (mixture of 100 CC and 100 MLO views). We computed overlap indices (the overlap index is defined as the ratio of the area of intersection to the area of interest) to quantify the agreement between the selected regions in each image. The averages of the largest overlap indices per image for the 5 radiologist-to-computer comparisons were directly related to the average number of regions per image traced by the radiologists (about 50% for 1 region/image, 84% for 2 regions/image and 96% for 3 regions/image). The average of the overlap indices with all of the TROIs was 73% for CAD and 76.8%+/−10.0% for the radiologists. This study indicates that the CAD determined ROIs could potentially be useful for a screening technique that includes stereo spot mammographyimaging.

  • Combination of digital mammography with semi-automated 3D breast ultrasound.
    Technology in Cancer Research & Treatment, 2004
    Co-Authors: Ajay Kapur, Mitchell M. Goodsitt, Paul L. Carson, Mark A. Helvie, Jeffrey Wayne Eberhard, Kai Erik Thomenius, Murtuza Lokhandwalla, Donald Joseph Buckley, Marilyn A. Roubidoux, Rebecca C. Booi
    Abstract:

    This paper describes work aimed at combining 3D ultrasound with full-field digital mammography via a semi-automatic prototype ultrasound scanning mechanism attached to the digital mammography system gantry. Initial efforts to obtain high x-ray and ultrasound image quality through a Compression Paddle are proving successful. Registration between the x-ray mammogram and ultrasound image volumes is quite promising when the breast is stably compressed. This prototype system takes advantage of many synergies between the co-registered digital mammography and pulse-echo ultrasound image data used for breast cancer detection and diagnosis. In addition, innovative combinations of advanced US and X-ray applications are being implemented and tested along with the basic modes. The basic and advanced applications are those that should provide relatively independent information about the breast tissues. Advanced applications include x-ray tomosynthesis, for 3D delineation of mammographic structures, and non-linear elasticity and 3D color flow imaging by ultrasound, for mechanical and physiological information unavailable from conventional, non-contrast x-ray and ultrasound imaging.