Breast arterial calcification on mammography and risk of coronary artery disease: a SCOT-HEART sub-study

Recurrent attention U-Net for segmentation and quantification of breast arterial calcifications on synthesized 2D mammograms

Breast arterial calcifications (BAC) are a type of calcification commonly observed on mammograms and are generally considered benign and not associated with breast cancer. However, there is accumulating observational evidence of an association between BAC and cardiovascular disease, the leading cause of death in women. We present a deep learning method that could assist radiologists in detecting and quantifying BAC in synthesized 2D mammograms. We present a recurrent attention U-Net model consisting of encoder and decoder modules that include multiple blocks that each use a recurrent mechanism, a recurrent mechanism, and an attention module between them. The model also includes a skip connection between the encoder and the decoder, similar to a U-shaped network. The attention module was used to enhance the capture of long-range dependencies and enable the network to effectively classify BAC from the background, whereas the recurrent blocks ensured better feature representation. The model was evaluated using a dataset containing 2,000 synthesized 2D mammogram images. We obtained 99.8861% overall accuracy, 69.6107% sensitivity, 66.5758% F-1 score, and 59.5498% Jaccard coefficient, respectively. The presented model achieved promising performance compared with related models.

Automated classification of fat-infiltrated axillary lymph nodes on screening mammograms

OBJECTIVE

Fat-infiltrated axillary lymph nodes (LNs) are unique sites for ectopic fat deposition. Early studies showed a strong correlation between fatty LNs and obesity-related diseases. Confirming this correlation requires large-scale studies, hindered by scarce labeled data. With the long-term goal of developing a rapid and generalizable tool to aid data labeling, we developed an automated deep learning (DL)-based pipeline to classify the status of fatty LNs on screening mammograms.

METHODS

Our internal data set included 886 mammograms from a tertiary academic medical institution, with a binary status of the fat-infiltrated LNs based on the size and morphology of the largest visible axillary LN. A two-stage DL model training and fine-tuning pipeline was developed to classify the fat-infiltrated LN status using the internal training and development data set. The model was evaluated on a held-out internal test set and a subset of the Digital Database for Screening Mammography.

RESULTS

Our model achieved 0.97 (95% CI: 0.94-0.99) accuracy and 1.00 (95% CI: 1.00-1.00) area under the receiver operator characteristic curve on 264 internal testing mammograms, and 0.82 (95% CI: 0.77-0.86) accuracy and 0.87 (95% CI: 0.82-0.91) area under the receiver operator characteristic curve on 70 external testing mammograms.

CONCLUSION

This study confirmed the feasibility of using a DL model for fat-infiltrated LN classification. The model provides a practical tool to identify fatty LNs on mammograms and to allow for future large-scale studies to evaluate the role of fatty LNs as an imaging biomarker of obesity-associated pathologies.

ADVANCES IN KNOWLEDGE

Our study is the first to classify fatty LNs using an automated DL approach.

Assessing cardiovascular risk with mammography and non-contrast chest CT: A review of the literature and clinical implications

Coronary artery disease (CAD) is the leading cause of mortality and disability globally. In the United States, about 7.2% of adults aged 20 and older are affected by CAD. However, due to its progression over decades, CAD is often undetected and unnoticed until plaque ruptures. This leads to partial or complete artery blockage, resulting in myocardial infarction. Thus, new screening methods for early detection of CAD are needed to prevent and minimize the morbidity and mortality from CAD. Vascular calcifications seen on mammography and non-contrast chest CT (NCCT) can be used for the early detection of CAD and are an accurate predictor of cardiovascular risk. This paper aims to review the basic epidemiology, pathophysiology, imaging findings, and correlation of long-term cardiovascular outcomes with vascular calcifications on mammography and NCCT.

Correlation Between Breast Arterial Calcifications and Higher Cardiovascular Risk: Awareness and Attitudes Amongst Canadian Radiologists Who Report Mammography

Background: Breast arterial calcification (BAC) on mammography correlates with increased cardiovascular risk. Reporting BAC is not standard practice. Our study evaluates the awareness of Canadian radiologists who report mammography of the clinical significance of BAC and their attitudes towards reporting BAC compared to their European and American counterparts. Methods: Following local institutional ethics approval, a 25 question survey (SurveyMonkey) was disseminated to Canadian radiologists via provincial and national society email lists. Responses were collected over 5 weeks (April-June 2022). Results: One hundred and eighty-six complete responses were collected. Sixty percent (112/186) were aware of the association between BAC and cardiovascular risk and 16% (29/186) document its presence in mammogram reports. Thirty five percent (65/186) occasionally document BAC if severe or in a young patient. Four percent (7/186) had local departmental guidelines on BAC reporting and 82% (153/186) agreed there is a need for national BAC reporting guidelines. Fewer Canadian radiologists were aware of the association between BAC and cardiovascular risk compared to European radiologists (60% vs 81%), report the presence of BAC compared to both European (15% vs 62%) and American (15% vs 35%) radiologists, and inform the patient of the presence of BAC compared to European radiologists (1% vs 46%). Conclusion: Canadian radiologists who report mammography were less aware of the association between BAC and cardiovascular risk than their European and American counterparts and were less likely to document the presence of BAC. Given the correlation of BAC with increased cardiovascular event risk, there is increased need for awareness as well as national BAC reporting guidelines.

Associations of Breast Arterial Calcifications with Cardiovascular Disease

Cardiovascular diseases (CVD), including coronary artery disease (CAD), continue to be the leading cause of global mortality among women. While traditional CVD/CAD prevention tools play a significant role in reducing morbidity and mortality among both men and women, current tools for preventing CVD/CAD rely on traditional risk factor-based algorithms that often underestimate CVD/CAD risk in women compared with men. In recent years, some studies have suggested that breast arterial calcifications (BAC), which are benign calcifications seen in mammograms, may be linked to CVD/CAD. Considering that millions of women older than 40 years undergo annual screening mammography for breast cancer as a regular activity, innovative risk prediction factors for CVD/CAD involving mammographic data could offer a gender-specific and convenient solution. Such factors that may be independent of, or complementary to, current risk models without extra cost or radiation exposure are worthy of detailed investigation. This review aims to discuss relevant studies examining the association between BAC and CVD/CAD and highlights some of the issues related to previous studies' design such as sample size, population types, method of assessing BAC and CVD/CAD, definition of cardiovascular events, and other confounding factors. The work may also offer insights for future CVD risk prediction research directions using routine mammograms and radiomic features other than BAC such as breast density and macrocalcifications.

The association between breast arterial calcification and atherosclerotic cardiovascular disease in an Australian population-based breast cancer case-control study

PURPOSE

Atherosclerotic cardiovascular disease (ASCVD) is a major cause of morbidity and mortality. Breast arterial calcification (BAC) on mammograms is not associated with breast cancer risk. However, there is increasing evidence supporting its association with cardiovascular disease (CVD). This study examines the association between BAC and ASCVD and their risk factors within an Australian population-based breast cancer study.

MATERIALS AND METHODS

Data from the controls who participated in the breast cancer environment and employment study (BCEES) were linked with the Western Australian Department of Health Hospital Morbidity database and Mortality Registry to obtain ASCVD outcomes and related risk factor data. Mammograms from participants with no prior history of ASCVD were assessed for BAC by a radiologist. Cox proportional hazards regression was used to examine the association between BAC and later occurrence of an ASCVD event. Logistic regression was used to investigate the factors associated with BAC.

RESULTS

A total of 1020 women with a mean age of 60 (sd = 7.0 years) were included and BAC found in 184 (18.0%). Eighty (7.8%) of the 1020 participants developed ASCVD, with an average time to event of 6.2 years (sd = 4.6) from baseline. In univariate analysis, participants with BAC were more likely to have an ASCVD event (HR = 1.96 95% CI 1.29-2.99). However, after adjusting for other risk factors, this association attenuated (HR = 1.37 95% CI 0.88-2.14). Increasing age (OR = 1.15, 95% CI 1.12-1.19) and parity (p_LRT < 0.001) were associated with BAC.

CONCLUSION

BAC is associated with increased ASCVD risk, but this is not independent of cardiovascular risk factors.

Mammography biomarkers of cardiovascular and musculoskeletal health: A review

Breast density (BD) and breast arterial calcifications (BAC) can expand the role of mammography. In premenopause, BD is related to body fat composition: breast adipose tissue and total volume are potential indicators of fat storage in visceral depots, associated with higher risk of cardiovascular disease (CVD). Women with fatty breast have an increased likelihood of hypercholesterolemia. Women without cardiometabolic diseases with higher BD have a lower risk of diabetes mellitus, hypertension, chest pain, and peripheral vascular disease, while those with lower BD are at increased risk of cardiometabolic diseases. BAC, the expression of Monckeberg sclerosis, are associated with CVD risk. Their prevalence, 13 % overall, rises after menopause and is reduced in women aged over 65 receiving hormonal replacement therapy. Due to their distinct pathogenesis, BAC are associated with hypertension but not with other cardiovascular risk factors. Women with BAC have an increased risk of acute myocardial infarction, ischemic stroke, and CVD death; furthermore, moderate to severe BAC load is associated with coronary artery disease. The clinical use of BAC assessment is limited by their time-consuming manual/visual quantification, an issue possibly solved by artificial intelligence-based approaches addressing BAC complex topology as well as their large spectrum of extent and x-ray attenuations. A link between BD, BAC, and osteoporosis has been reported, but data are still inconclusive. Systematic, standardised reporting of BD and BAC should be encouraged.

Relationship between Arterial Calcifications on Mammograms and Cardiovascular Events: A Twenty-Three Year Follow-Up Retrospective Cohort Study

PURPOSE

Breast arterial calcifications (BAC) have been associated with cardiovascular diseases. We aimed to examine whether the presence of BAC could predict the development of cardiovascular events in the very long term, as evidence has suggested.

PATIENTS AND METHODS

We conducted a 23-year follow-up retrospective cohort study considering women specifically studied for breast cancer. After reviewing the mammograms of 1759 women, we selected 128 patients with BAC and an equal number of women without BAC.

RESULTS

Women with BAC had higher relative risk (RR) for cardiovascular events, globally 1.66 (95% CI): 1.31-2.10 vs. 0.53 (0.39-0.72), and individually for ischemic heart disease 3.25 (1.53-6.90) vs. 0.85 (0.77-0.94), hypertensive heart disease 2.85 (1.59-5.09) vs. 0.79 (0.69-0.89), valvular heart disease 2.19 (1.28-3.75) vs. 0.83 (0.73-0.94), congestive heart failure 2.06 (1.19-3.56) vs. 0.85 (0.75-0.96), peripheral vascular disease 2.8 (1.42-5.52) vs. 0.85 (0.76-0.94), atrial fibrillation 1.83 (1.09-3.08) vs. 0.86 (0.76-0.98), and lacunar infarction 2.23 (1.21-4.09) vs. 0.86 (0.77-0.96). Cox's multivariate analysis, also considering classical risk factors, indicated that this BAC was significantly and independently associated with survival (both cardiovascular event-free and specific survival; 1.94 (1.38-2.73) and 6.6 (2.4-18.4)).

CONCLUSIONS

Our data confirm the strong association of BAC on mammograms and the development cardiovascular events, but also evidence the association of BAC with cardiovascular event-free and specific survival.

Association Between Breast Arterial Calcification on Mammography and Coronary Artery Disease: A Systematic Review and Meta-Analysis

Background: Breast arterial calcification (BAC), which may be detected during screening mammography, is hypothesized to be a noninvasive imaging marker that may enhance cardiovascular risk assessment. Materials and Methods: In this systematic review and meta-analysis, we sought to assess the association between BAC and coronary artery disease (CAD) by conducting a meta-analysis. We conducted a literature search of PubMed, Scopus, Cochrane library, ClinicalTrials.gov, and conference proceedings, from inception through December 24, 2019. The outcome of interest was the presence of CAD in patients with BAC. This was reported as crude and adjusted odds ratio (OR). Results: A total of 18 studies comprising 33,494 women (mean age of 60.8 ± 3.7 years, 25% with diabetes, 57% with hypertension, and 21% with history of tobacco smoking) were included in the current meta-analysis. The prevalence of BAC among study participants was 10%. There was a statistically significant association between BAC and CAD (unadjusted OR 2.14; 95% confidence interval [CI] 1.63-2.81, p < 0.001, I2 = 76.5%). Moreover, adjusted estimates were available from 10 studies and BAC was an independent predictor of CAD (OR 2.39; 95% CI 1.68-3.41, p < 0.001, I2 = 61.7%). In the meta-regression analysis, covariates included year of publication, age, hypertension, diabetes mellitus, and history of tobacco smoking. None of these study covariates explained the heterogeneity across studies. Conclusions: BAC detected as part of screening mammography is a promising noninvasive imaging marker that may enhance CAD risk prediction in women. The clinical value of BAC for cardiovascular risk stratification merits further evaluation in large prospective studies.

Breast Arterial Calcifications: Reporting Preferences and Impact on Screening for Coronary Artery Disease

OBJECTIVE

Breast arterial calcifications (BAC) have been shown to correlate with measures of coronary artery disease risk stratification, although reporting of BAC is optional by BI-RADS guidelines. The purpose of this study is to determine referring provider preferences in BAC reporting on mammography reports and if such reporting has any impact on patient management.

METHODS

This study was approved by the local institutional review board. A voluntary eight-question survey regarding the preferences and outcomes of BAC reporting on mammography was distributed to 1085 primary care physicians, obstetrics and gynecologists, medical oncologists, and breast and general surgeons in our health system via a secure online platform. Data analysis including Pearson chi-square was performed with a P-value of <0.05 for significance.

RESULTS

A response rate of 19.1% (207/1085) was attained, with 21/207 (10.1%) of respondents indicating they do not routinely order mammograms excluded from further analysis. A total of 62.4% (116/186) of ordering physicians indicated a preference for reporting of BAC in both the body and impression of the radiology report, with 82.3% (153/186) of respondents placing importance on the quantity of atherosclerotic calcifications. Most participants (148/186, 79.6%) reported that the presence of BAC would prompt further investigation for coronary artery disease and associated risk factors.

CONCLUSION

The majority of responding physicians indicated a preference for detailed reporting of BAC and that such reporting would impact patient care. Understanding referring provider preferences regarding ancillary findings of BAC will allow for improved communication and value in mammography.

Breast Arterial Calcifications on Mammography: A Survey of Practicing Radiologists

OBJECTIVE

To explore current practice patterns of reporting and issuing recommendations based on the presence of breast arterial calcifications on mammography and existing knowledge of their prevalence and associated factors.

METHODS

An online anonymous 19-question survey was distributed to 2583 practicing radiologists who were members of the Society of Breast Imaging. Questions covered demographics, breast imaging training, practice type, and knowledge regarding the epidemiology and potential clinical significance of breast arterial calcifications detected on mammograms. Differences between groups were calculated using the chi-square test or Fisher exact test. An α level of 0.05 was used to determine statistical significance.

RESULTS

Response rate was 22% (364/1662). The median age of respondents was 51 years (range: 29-76) and most were female (248/323, 77%). The most prevalent characteristics among respondents were as follows: 69% (223/323) had completed a breast imaging fellowship, 55% (179/323) were in private practice, 49% (158/323) practiced dedicated breast imaging, and 38% (124/323) had been in practice for more than 20 years. The prevalence of breast arterial calcifications was correctly estimated to be 1%-30% by 39% (125/323) of respondents. Most respondents correctly recognized the growing evidence of an association between breast arterial calcifications and coronary artery disease (275/323, 85%). However, only 15% (48/323) always reported the presence of these calcifications, and of those who report them at any time, only 0.7% (2/274) always issued recommendations.

CONCLUSION

There are differences in both knowledge of the epidemiology of breast arterial calcifications and practices around their reporting amongst breast radiologists.

The potential impact of mammographic breast arterial calcification on physician practices in a primary care setting

Aim: This study sought to determine breast arterial calcification (BAC) prevalence in a primary care setting and its potential use in guiding further cardiovascular workup. Materials & methods: A radiologist reviewed 282 consecutive mammograms. Characteristics of BAC-positive and negative women were compared. Results: BAC prevalence was 34%. BAC-positive women were older (mean age: 60 vs 52, p < 0.001), had higher mean 10-year cardiac risk (11 vs 6%, p < 0.001), more hypertension (65 vs 40%, p < 0.001) and coronary artery disease (10 vs 2%, p = 0.0041), statin (50 vs 32%, p = 0.006) and aspirin use (28 vs 16%, p = 0.012). Thirty-seven percent (33/96) of BAC-positive women could potentially benefit from further cardiac testing. Conclusion: Mammography identifies BAC-positive women with low traditionally assessed cardiovascular risk who might benefit from further cardiovascular workup.

Is breast arterial calcification associated with coronary artery disease?-A systematic review and meta-analysis

BACKGROUND

There is increasing evidence that breast arterial calcification (BAC), an incidental finding on 3-29% of mammograms, could be used to screen for coronary artery disease (CAD). We conducted a systematic review to assess the associations between BAC and CAD and its risk factors (hypertension, hypercholesterolemia, diabetes mellitus and smoking).

METHODS AND FINDINGS

MEDLINE and EMBASE databases and references of relevant papers were searched up to 18 February 2020 for English language studies that evaluated the associations of BAC and CAD and its risk factors. A single reviewer extracted all data and assessed study quality with verification by another independent reviewer, if required. Across 31 studies (n = 35,583; 3 longitudinal and 28 cross-sectional studies) that examined the association of BAC and CAD, the OR was 2.61 (95% CI 2.12-3.21; I2 = 71%). Sub-analysis of studies that graded BAC severity using the 4- (4 studies) or 12-point scale systems (3 studies) revealed an association with CAD and moderate-severe BAC (OR 4.83 (95%CI 1.50-15.54) and OR 2.95 (95%CI 1.49-5.84), respectively) but not mild BAC (OR 2.04 (95%CI 0.82-5.05) and OR 1.08 (95%CI 0.42-2.75), respectively). BAC was associated with hypertension (42 studies; n = 32,646; OR 1.80; 95% CI 1.47-2.21; I2 = 85%) and diabetes mellitus (51 studies; n = 53,464; OR 2.17; 95% CI 1.82-2.59; I2 = 75%) but not with hypercholesterolemia (OR 1.31; 95%CI 0.97-1.77; I2 = 67%). Smoking was inversely associated with BAC (35 studies; n = 40,002; OR 0.54; 95% CI 0.42-0.70; I2 = 83%). Studies mostly included symptomatic women. Marked heterogeneity existed and publication bias may be present.

CONCLUSIONS

BAC is associated with CAD, diabetes mellitus and hypertension and inversely associated with smoking. Whether BAC could screen for CAD cannot be determined from current published data due to the lack of larger prospective studies. A consensus approach to quantifying BAC may also facilitate further translation into clinical care. PROSPERO: CRD42020141644.