Background and objectives: Because previous studies have not distinguished between intimal (atherosclerotic) and medial vascular calcification, the prevalence and clinical significance of either condition in chronic or end-stage kidney disease (CKD or ESKD) are unknown. We hypothesized that breast arterial calcification (BAC) is exclusively medial and that mammography can serve as a useful marker of generalized medial calcification in CKD and ESKD.
Design, setting, participants, & measurements: Arterial calcification was identified histologically in breast tissue or visually in mammograms and radiographs of extremities from patients with CKD or ESKD.
Results: Medial calcification but no intimal calcification was present in all 16 specimens from patients with CKD or ESKD. In 71 women with ESKD, BAC was present on mammograms in 63% compared with 17% in women without renal insufficiency matched for age, race, and diabetes (P < 0.001). Age and ESKD duration were significant, independent predictors of BAC. BAC was also present in 36% of mammograms from the same patients performed 5.5 ± 0.7 years before the onset of ESKD (P < 0.05 versus control) but in only 14% of patients with stage 3 CKD. Comparison of mammograms and extremity radiographs revealed that BAC was present in over 90% of patients with peripheral arterial calcification (PAC), and PAC was observed in less than 6% of patients without BAC.
Conclusions: BAC is a specific and useful marker of medial vascular calcification in CKD, and its prevalence is markedly increased in ESKD and advanced CKD.
With the advent of new detector technology, digital tomosynthesis imaging of the breast has, in the past few years, become a technique intensely investigated as a replacement for planar mammography. As with all other x-ray-based imaging methods, radiation dose is of utmost concern in the development of this new imaging technology. For virtually all development and optimization studies, knowledge of the radiation dose involved in an imaging protocol is necessary. A previous study characterized the normalized glandular dose in tomosynthesis imaging and its variation with various breast and imaging system parameters. This characterization was performed with x-ray spectra generated by molybdenum and rhodium targets. In the recent past, many preliminary patient studies of tomosynthesis imaging have been reported in which the x-ray spectra were generated with x-ray tubes with tungsten targets. The differences in x-ray distribution among spectra from these target materials make the computation of new normalized glandular dose values for tungsten target spectra necessary. In this study we used previously obtained monochromatic normalized glandular dose results to obtain spectral results for twelve different tungsten target x-ray spectra. For each imaging condition, two separate values were computed: the normalized glandular dose for the zero degree projection angle (D g N 0 ), and the ratio of the glandular dose for non-zero projection angles to the glandular dose for the zero degree projection (the relative glandular dose, RGD(α)). It was found that D g N 0 is higher for tungsten target x-ray spectra when compared with D g N 0 values for molybdenum and rhodium target spectra of both equivalent tube voltage and first half value layer. Therefore, the D g N 0 for the twelve tungsten target x-ray spectra and different breast compositions and compressed breast thicknesses simulated are reported. The RGD(a) values for the tungsten spectra vary with the parameters studied in a similar manner to that found for the molybdenum and rhodium target spectra. The surface fit equations and the fit coefficients for RGD(a) included in the previous study were also found to be appropriate for the tungsten spectra.
Background and objectives: CKD is a risk factor for medial artery calcification, but the CKD stage at which this risk begins is unknown. Because breast arterial calcification (BAC) is a marker of generalized medial arterial calcification, mammography was used to detect medial arterial calcification in women with different CKD stages.
Design, setting, participants, & measurements: This was a retrospective, cross-sectional study of women with and without CKD matched for age and diabetes and identified from mammograms obtained in 2006–2011. BAC was scored as present or absent per visual inspection.
Results: A total of 146 women with stage 3 CKD and 54 with stage 4/5 CKD were identified. An additional 21 patients with ESRD were identified and added to a previous cohort of 71 patients. Mean age was 64 years for CKD 3, 63 for CKD 4, and 59 for ESRD. Half of each group had diabetes. Compared with controls, the odds ratios for BAC were 1.44 in CKD 3 (95% confidence interval [CI], 0.82–2.53), 2.69 in CKD 4 (95% CI, 1.14–6.33), and 7.19 in ESRD (95% CI, 3.77–13.7) and did not differ with diabetic status or race. In a multivariable logistic model, age (P<0.001) and estimated GFR (P=0.005) were independent predictors of BAC. The odds ratio for BAC increased 4% for each milliliter per minute per 1.73 m2 decrease in estimated GFR. The prevalence of BAC in CKD was increased in each decade of age over 49 years.
Conclusions: CKD is an independent risk factor for medial arterial calcification.
OBJECTIVE. The objective of this study was to investigate the impact of decreasing breast compression during digital mammography and breast tomosynthesis (DBT) on perceived pain and image quality. MATERIALS AND METHODS. In this two-part study, two groups of women with prior mammograms were recruited. In part 1, subjects were positioned for craniocaudal (CC) and mediolateral oblique (MLO) views, and four levels of compression force were applied to evaluate changes in breast thickness, perceived pain, and relative tissue coverage. No imaging was performed. In part 2, two MLO DBT images of one breast of each patient were acquired at standard and reduced compression. Blurring artifacts and tissue coverage were judged by three breast imaging radiologists, and compression force, breast thickness, relative tissue coverage, and perceived pain were recorded. RESULTS. Only the frst reduction in force was feasible because further reduction resulted in inadequate breast immobilization. Mean force reductions of 48% and 47% for the CC and MLO views, respectively, resulted in a signifcantly reduced perceived pain level, whereas the thickness of the compressed breast increased by 0.02 cm (CC view) and 0.09 (MLO view, part 1 of the study) and 0.38 cm (MLO view, part 2 of the study), respectively, with no change in tissue coverage or increase in motion blurring. CONCLUSION. Mammography and DBT acquisitions may be possible using half of the compression force used currently, with a signifcant and substantial reduction in perceived pain with no clinically signifcant change in breast thickness and tissue coverage.
Purpose: To develop a set of accurate 2D models of compressed breasts undergoing mammography or breast tomosynthesis, based on objective analysis, to accurately characterize mammograms with few linearly independent parameters, and to generate novel clinically realistic paired cranio-caudal (CC) and medio-lateral oblique (MLO) views of the breast. Methods: We seek to improve on an existing model of compressed breasts by overcoming detector size bias, removing the nipple and non-mammary tissue, pairing the CC and MLO views from a single breast, and incorporating the pectoralis major muscle contour into the model. The outer breast shapes in 931 paired CC and MLO mammograms were automatically detected with an in-house developed segmentation algorithm. From these shapes three generic models (CC-only, MLO-only, and joint CC/MLO) with linearly independent components were constructed via principal component analysis (PCA). The ability of the models to represent mammograms not used for PCA was tested via leave-one-out cross-validation, by measuring the average distance error (ADE). Results: The individual models based on six components were found to depict breast shapes with accuracy (mean ADE-CC = 0.81 mm, ADE-MLO = 1.64 mm, ADE-Pectoralis = 1.61 mm), outperforming the joint CC/MLO model (P ≤ 0.001). The joint model based on 12 principal components contains 99.5% of the total variance of the data, and can be used to generate new clinically realistic paired CC and MLO breast shapes. This is achieved by generating random sets of 12 principal components, following the Gaussian distributions of the histograms of each component, which were obtained from the component values determined from the images in the mammography database used. Conclusion: Our joint CC/MLO model can successfully generate paired CC and MLO view shapes of the same simulated breast, while the individual models can be used to represent with high accuracy clinical acquired mammograms with a small set of parameters. This is the first step toward objective 3D compressed breast models, useful for dosimetry and scatter correction research, among other applications.