Influence of breast compression pressure on the performance of population-based mammography screening

Using automated software evaluation to improve the performance of breast radiographers in tomosynthesis screening

OBJECTIVE

To improve breast radiographers' individual performance by using automated software to assess the correctness of breast positioning and compression in tomosynthesis screening.

MATERIALS AND METHODS

In this retrospective longitudinal analysis of prospective cohorts, six breast radiographers with varying experience in the field were asked to use automated software to improve their performance in breast compression and positioning. The software tool automatically analyzes craniocaudal (CC) and mediolateral oblique (MLO) views for their positioning quality by scoring them according to PGMI classifications (perfect, good, moderate, inadequate) and checking whether the compression pressure is within the target range. The positioning and compression data from the studies acquired before the start of the project were used as individual baselines, while the data obtained after the training were used to test whether conscious use of the software could help the radiographers improve their performance. The percentage of views rated perfect or good and the percentage of views in target compression were used as overall metrics to assess changes in performance.

RESULTS

Following the use of the software, all radiographers significantly increased the percentage of images rated as perfect or good in both CCs and MLOs. Individual improvements ranged from 7 to 14% for CC and 10 to 16% for MLO views. Moreover, most radiographers exhibited improved compression performance in CCs, with improvements up to 16%.

CONCLUSION

Active use of a software tool to automatically assess the correctness of breast compression and positioning in breast cancer screening can improve the performance of radiographers.

CLINICAL RELEVANCE STATEMENT

This study suggests that the use of a software tool for automatically evaluating correctness of breast compression and positioning in breast cancer screening can improve the performance of radiographers on these metrics, which may ultimately lead to improved screening outcomes.

KEY POINTS

• Proper breast positioning and compression are critical in breast cancer screening to ensure accurate diagnosis. • Active use of the software increased the quality of craniocaudal and mediolateral oblique views acquired by all radiographers. • Improved performance of radiographers is expected to improve screening outcomes.

Successes and challenges in extracting information from DICOM image databases for audit and research

In radiography, much valuable associated data (metadata) is generated during image acquisition. The current setup of picture archive and communication systems (PACS) can make extraction of this metadata difficult, especially as it is typically stored with the image. The aim of this work is to examine the current challenges in extracting image metadata and to discuss the potential benefits of using this rich information. This work focuses on breast screening, though the conclusions are applicable to other modalities.The data stored in PACS contain information, currently underutilised, and is of great benefit for auditing and improving imaging and radiographic practice. From the literature, we present examples of the potential clinical benefit such as audits of dose, and radiographic practice, as well as more advanced research highlighting the effects of radiographic practice, e.g. cancer detection rates affected by imaging technology.This review considers the challenges in extracting data, namely,• The search tools for data on most PACS are inadequate being both time-consuming and limited in elements that can be searched.• Security and information governance considerations• Anonymisation of data if required• Data curationThe review describes some solutions that have been successfully implemented.• Retrospective extraction: direct query on PACS• Extracting data prospectively• Use of structured reports• Use of trusted research environmentsUltimately, the data access process will be made easier by inclusion during PACS procurement. Auditing data from PACS can be used to improve quality of imaging and workflow, all of which will be a clinical benefit to patients.

Are mammography image acquisition factors, compression pressure and paddle tilt, associated with breast cancer detection in screening?

OBJECTIVES

To assess the associations between objectively measured mammographic compression pressure and paddle tilt and breast cancer (BC) detected at the same ("contemporaneous") screen, subsequent screens, or in-between screens (interval cancers).

METHODS

Automated pressure and paddle tilt estimates were derived for 80,495 mammographic examinations in a UK population-based screening programme. Adjusted logistic regression models were fitted to estimate the associations of compression parameters with BC detected at contemporaneous screen (777 cases).Nested case-control designs were used to estimate associations of pressure and tilt with: (a) interval cancer (148 cases/625 age-matched controls) and (b) subsequent screen-detected cancer (344/1436), via conditional logistic regression.

RESULTS

Compression pressure was negatively associated with odds of BC at contemporaneous screen (odds ratio (OR) for top versus bottom third of the pressure distribution: 0.74; 95% CI 0.60, 0.92; P-for-linear-trend (Pt) = 0.007). There was weak evidence that moderate pressure at screening was associated with lower odds of interval cancer (OR for middle versus bottom third: 0.63; 95% CI 0.38, 1.05; p = 0.079), but no association was found between pressure and the odds of BC at subsequent screen. There was no evidence that paddle tilt was associated with the odds of contemporaneous, subsequent screen or interval cancer detection.

CONCLUSIONS

Findings are consistent with compression pressure, but not paddle tilt, affecting the performance of mammographic screening by interfering with its ability to detect cancers.

ADVANCES IN KNOWLEDGE

Inadequate or excessive compression pressure at screening may contribute to a reduced ability to detect cancers, resulting in a greater number of interval cancer cases.

Pacemaker in patients undergoing mammography: A limitation for breast cancer diagnosis?

INTRODUCTION

A pacemaker may affect the utility of a mammogram in several ways. The aim of this study is to summarize our institution's experience with mammograms among patients with a cardiac pacemaker, focusing on the diagnostic workup among patients with a newly diagnosed ipsilateral breast cancer.

METHODS

A retrospective search of all mammography reports between January 2011 and April 2021 was conducted for identifying cases of patients with a pacemaker. Demographic and clinical characteristics as well as mammography-derived quality parameters and findings were categorized and statistically compared.

RESULTS

The incidence of pacemaker concurrence in mammographic examination, although apparently slightly under-documented, accounted for 0.33% of cases. Population mean age was 71.7 years, and most patients (79%) had a left-sided pacemaker. The pacemaker was much more likely to be projected on the medio-lateral-oblique (96%) than on the cranio-caudal view (10%), on the axilla rather than the breast, and on the retro-pectoral rather than the pre-pectoral region (P < 0.001 for all). Compression force decreased by up to 23.0% (P < 0.001) and breast thickness increased by up to 9.5% (P < 0.001) for the ipsilateral vs. the contralateral side. Among 11 patients with newly diagnosed ipsilateral breast cancer, the pacemaker partially projected on the tumour region in two cases, and significantly obscured the tumour in another two.

CONCLUSION

Although rare, the coexistence of a pacemaker in patients undergoing mammography is associated with reduced image quality due to suboptimal breast visualization and reduced compression, and as a result, this may eventually lead to decreased diagnostic efficacy.

Artificial intelligence to support person-centred care in breast imaging - A scoping review

AIM

To overview Artificial Intelligence (AI) developments and applications in breast imaging (BI) focused on providing person-centred care in diagnosis and treatment for breast pathologies.

METHODS

The scoping review was conducted in accordance with the Joanna Briggs Institute methodology. The search was conducted on MEDLINE, Embase, CINAHL, Web of science, IEEE explore and arxiv during July 2022 and included only studies published after 2016, in French and English. Combination of keywords and Medical Subject Headings terms (MeSH) related to breast imaging and AI were used. No keywords or MeSH terms related to patients, or the person-centred care (PCC) concept were included. Three independent reviewers screened all abstracts and titles, and all eligible full-text publications during a second stage.

RESULTS

3417 results were identified by the search and 106 studies were included for meeting all criteria. Six themes relating to the AI-enabled PCC in BI were identified: individualised risk prediction/growth and prediction/false negative reduction (44.3%), treatment assessment (32.1%), tumour type prediction (11.3%), unnecessary biopsies reduction (5.7%), patients' preferences (2.8%) and other issues (3.8%). The main BI modalities explored in the included studies were magnetic resonance imaging (MRI) (31.1%), mammography (27.4%) and ultrasound (23.6%). The studies were predominantly retrospective, and some variations (age range, data source, race, medical imaging) were present in the datasets used.

CONCLUSIONS

The AI tools for person-centred care are mainly designed for risk and cancer prediction and disease management to identify the most suitable treatment. However, further studies are needed for image acquisition optimisation for different patient groups, improvement and customisation of patient experience and for communicating to patients the options and pathways of disease management.

Influence of mammographic density and compressed breast thickness on true mammographic sensitivity: a cohort study

Understanding the detectability of breast cancer using mammography is important when considering nation-wide screening programmes. Although the role of imaging settings on image quality has been studied extensively, their role in detectability of cancer at a population level is less well studied. We wish to quantify the association between mammographic screening sensitivity and various imaging parameters. Using a novel approach applied to a population-based breast cancer screening cohort, we specifically focus on sensitivity as defined in the classical diagnostic testing literature, as opposed to the screen-detected cancer rate, which is often used as a measure of sensitivity for monitoring and evaluating breast cancer screening. We use a natural history approach to model the presence and size of latent tumors at risk of detection at mammography screening, and the screening sensitivity is modeled as a logistic function of tumor size. With this approach we study the influence of compressed breast thickness, x-ray exposure, and compression pressure, in addition to (percent) breast density, on the screening test sensitivity. When adjusting for all screening parameters in addition to latent tumor size, we find that percent breast density and compressed breast thickness are statistically significant factors for the detectability of breast cancer. A change in breast density from 6.6 to 33.5% (the inter-quartile range) reduced the odds of detection by 61% (95% CI 48-71). Similarly, a change in compressed breast thickness from 46 to 66 mm reduced the odds by 42% (95% CI 21-57). The true sensitivity of mammography, defined as the probability that an examination leads to a positive result if a tumour is present in the breast, is associated with compressed breast thickness after accounting for mammographic density and tumour size. This can be used to guide studies of setups aimed at improving lesion detection. Compressed breast thickness-in addition to breast density-should be considered when assigning complementary screening modalities and personalized screening intervals.

EFFECT OF MAMMOGRAPHY IMAGING PROCEDURE ON SERUM INFLAMMATORY AND/OR TUMOR MARKER LEVELS

Mammography is one of the gold standard screening tests for breast cancer. The effects of mammography procedure on blood parameters are not known. This study aimed to investigate whether the procedure-associated breast compression affects the widely and simultaneously performed blood measurements of C-reactive protein (CRP), carcinoembryonic antigen (CEA), and cancer antigen (CA) 15-3. According to breast ultrasound examination results, participants were divided into 3 groups as follows: group 1 (participants with breast mass size ≥20.0 mm, n=48); group 2 (participants with breast mass size <20.0 mm, n=17); and group 3 (participants with no breast mass, n=23). In groups 1 and 2, on the day of the mammographic imaging study, serum CRP, CEA, and CA 15-3 levels were measured before and after the imaging study. Participants in group 3 had their blood parameters measured without mammography and/or any breast compression. Post-mammography blood measurements displayed a significant increase in serum CRP levels, and a significant decrease in serum CEA and CA 15-3 levels in group 1 (in comparison with the same day pre-mammography blood sampling levels; p<0.05 all). Although pre-mammography serum CEA levels in group 1 participants were significantly higher than those in group 2 and 3 participants, this significant elevation became nonsignificant at post-mammography measurements (p<0.05 and p>0.05, respectively). On the day of the mammographic imaging study, the optimal time of blood sampling for testing CRP, CEA and CA 15-3 levels in persons with a breast mass is before, but not after the mammographic imaging procedure. This issue requires additional detailed studies.

Comparison of technical parameters and women's experience between self-compression and standard compression modes in mammography screening: a single-blind randomized clinical trial

OBJECTIVES

We compared the compression force, breast thickness, and glandular dose, as well as the severity of discomfort and women's experience between the patient-assisted compression (PAC) and standard compression (SC) modes.

MATERIALS AND METHODS

We conducted a prospective randomized controlled study at Hospital del Mar in Barcelona, Spain. We included 448 asymptomatic women aged 50 to 69 years old, attending their screening round from December 2017 to December 2019. Mammograms included the two bilateral views. In each woman, one breast was studied with SC and the other with PAC. The mode used in each breast was selected following a randomized list. Compression force, breast thickness, and average glandular dose were obtained for each of the 1792 images. We also recorded the degree of discomfort and women's experience, after mammogram acquisitions, using a predefined survey.

RESULTS

Higher compression forces were obtained with PAC than with SC (99.27 N vs 83.25 N, p < 0.001). Breast thickness mode (56.11 mm vs 57.52 mm, p = 0.015) and glandular dose (1.34 mGy vs 1.37 mGy, p = 0.018) were lower in PAC. The discomfort score was slightly higher with PAC (mean 3.94 vs 3.69, p = 0.042), but in the satisfaction survey, more women reported that PAC caused less discomfort. Additionally, 63.2% of women (289/448) preferred PAC.

CONCLUSION

PAC achieved higher compression forces without impairing the other technical imaging parameters and enhanced women's experience of screening mammography. We believe there were no clinically significant differences in the severity of discomfort between the two modes.

KEY POINTS

• Self-compression allows higher compression forces than the standard compression mode. • Self-compression does not affect technical imaging parameters. • Self-compression improved women's experience of screening mammography when standard compression was used on one breast and self-compression on the other.

Breast Implant-Related Adverse Events During Mammography: An Assessment of the Food and Drug Administration Manufacturer and User Facility Device Experience Database

BACKGROUND

Adverse events arising in patients with breast implants during mammography reported by the Food and Drug Administration include implant rupture, pain, and impaired visualization. However, data supporting these claims were collected in 2004, and since, newer implant generations have been developed with overall rate of implantation increasing by 48%.

OBJECTIVES

This article aims to determine the current incidence of implant-related adverse events arising during mammography.

METHODS

We analyzed reports regarding silicone and saline breast implants published in the Food and Drug Administration Manufacturer and User Facility Device Experience database between 2008 and November 2018. Search terms included "mammogram," "mammography," "radiograph," "breast cancer screening," "breast cancer test," and "x-ray."

RESULTS

Of the 20 539 implant-related adverse events available in the Manufacturer and User Facility Device Experience database, 427 were retrieved using our search strategy and 41 were related to mammography. Thirty-five of identified cases (85.4%) reported implant rupture, of which 19 (54.3%) were confirmed by a healthcare professional, 9 (25.7%) were clinically confirmed by saline implant deflation, and 7 (20.0%) were unverified reports by patients. Sixteen ruptures (45.7%) occurred with silicone implants, whereas 19 ruptures (54.3%) occurred with saline. Other adverse events included pain (29.3%), change in implant appearance (14.6%), and swelling (7.3%).

CONCLUSIONS

Although implant rupture, pain, change in implant appearance, and swelling may occur, minimal implant-related adverse events arise during mammography. Given the extremely low reported risk of implant rupture, this should neither prevent patients from adhering to breast cancer screening programs nor deter patients from seeking breast implants. Patients should be aware of these reported risks and discuss screening options with their breast cancer screening team.

Flat-panel conebeam CT in the clinic: history and current state

Research into conebeam CT concepts began as soon as the first clinical single-slice CT scanner was conceived. Early implementations of conebeam CT in the 1980s focused on high-contrast applications where concurrent high resolution ( < 200    μ m ), for visualization of small contrast-filled vessels, bones, or teeth, was an imaging requirement that could not be met by the contemporaneous CT scanners. However, the use of nonlinear imagers, e.g., x-ray image intensifiers, limited the clinical utility of the earliest diagnostic conebeam CT systems. The development of consumer-electronics large-area displays provided a technical foundation that was leveraged in the 1990s to first produce large-area digital x-ray detectors for use in radiography and then compact flat panels suitable for high-resolution and high-frame-rate conebeam CT. In this review, we show the concurrent evolution of digital flat panel (DFP) technology and clinical conebeam CT. We give a brief summary of conebeam CT reconstruction, followed by a brief review of the correction approaches for DFP-specific artifacts. The historical development and current status of flat-panel conebeam CT in four clinical areas-breast, fixed C-arm, image-guided radiation therapy, and extremity/head-is presented. Advances in DFP technology over the past two decades have led to improved visualization of high-contrast, high-resolution clinical tasks, and image quality now approaches the soft-tissue contrast resolution that is the standard in clinical CT. Future technical developments in DFPs will enable an even broader range of clinical applications; research in the arena of flat-panel CT shows no signs of slowing down.

Visualization of the Nipple in Profile: Does It Really Affect Selected Outcomes in Organized Mammographic Screening?

OBJECTIVE

To investigate whether having the nipple imaged in profile was associated with breast characteristics or compression parameters, and whether it affected selected outcomes in screening with standard digital mammography or digital breast tomosynthesis.

METHODS

In this IRB-approved retrospective study, results from 87 450 examinations (174 900 breasts) performed as part of BreastScreen Norway, 2016-2019, were compared by nipple in profile status and screening technique using descriptive statistics and generalized estimating equations. Unadjusted and adjusted odds ratios with 95% confidence intervals (95% CIs) were estimated for outcomes of interest, including age, breast volume, volumetric breast density, and compression force as covariates.

RESULTS

Achieving the nipple in profile versus not in profile was associated with lower breast volume (845.1 cm3 versus 1059.9 cm3, P < 0.01) and higher mammographic density (5.6% versus 4.4%, P < 0.01). Lower compression force and higher compression pressure were applied to breasts with the nipple in profile (106.6 N and 11.5 kPa) compared to the nipple not in profile (110.8 N and 10.5 kPa, P < 0.01 for both). The adjusted odds ratio was 0.95 (95% CI: 0.88-1.02; P = 0.15) for recall and 0.92 (95% CI: 0.77-1.10; P = 0.36) for screen-detected cancer for nipple in profile versus not in profile.

CONCLUSION

Breast characteristics and compression parameters might hamper imaging of the nipple in profile. However, whether the nipple was in profile or not on the screening mammograms did not influence the odds of recall or screen-detected cancer, regardless of screening technique.

Digital breast tomosynthesis in a population based mammographic screening program: Breast compression and early performance measures

PURPOSE

We aimed to determine if compression force or pressure could be associated with early performance measures for women screened with digital breast tomosynthesis (DBT) in BreastScreen Norway. Early performance measures included rates of consensus, recall, and screen-detected breast cancer.

METHOD

Data on compression force and pressure, compressed breast thickness and breast characteristics were extracted from an automated software for density assessment of DBT screening examinations for 25,286 women. For descriptive analyses, force (Newton, N) and pressure (kilopascal, kPa) were categorized into quartiles. Analyses were stratified by mammographic view, craniocaudal (CC) and mediolateral oblique (MLO). Logistic regression with restricted cubic splines was used to investigate the association between force and pressure as continuous exposures and early performance measures adjusted for age, compressed breast thickness and fibroglandular volume.

RESULTS

Mean age of the screened women was 60.7 (SD = 5.2) years. Mean compression force was 90.8 (SD = 14.2) N for CC and 106.3 (SD = 20.6) N for MLO, and pressure was 11.3 (SD = 3.6) kPa for CC and 8.7 (SD = 2.0) kPa for MLO. The highest rates of screen-detected cancer were observed for low force (1.04 % for <82.5 N for CC and 1.07 % for <92.0 N for MLO) and low pressure (1.07 % for <7.2 kPa for MLO). No association was found between force or pressure as continuous exposures and early performance measures in adjusted regression analyses.

CONCLUSIONS

We found the highest rates of screen-detected cancer for low force and pressure, but no significant association between continuous values of force or pressure and early performance measures in DBT. The findings might indicate that the levels of force and pressure in DBT are of lower significance for screening performance than reported in standard digital mammography.

Self-reported Pain Associated With Screening With Digital Breast Tomosynthesis

OBJECTIVE

We aimed to investigate self-reported pain during screening with digital breast tomosynthesis (DBT).

METHODS

The study was approved by the Regional Committee for Medical and Health Research Ethics in the South East of Norway (2015/424). Women completed a questionnaire about experienced pain directly after the examination, August-November 2019. A numeric rating scale (NRS, 0-10) was used. Data on compression force (N), pressure (kPa), and compressed breast thickness (mm) were obtained from the Digital Imaging and Communication in Medicine header and density assessment software. Stepwise ordinary least-squares regression was used to estimate mean self-reported pain score with 95% confidence interval (CI) for values of compression force, pressure, and compressed breast thickness.

RESULTS

The mean pain score was 1.9, whereof 19.3% (822/4266) of the women reported moderate or severe pain. The mean pain score of 2.6 (95% CI: 2.4-2.7) was observed at a compression force of 60 N, decreasing to 1.3 (95% CI: 1.2-1.4) at 130 N. The mean pain score of 1.3 (95% CI: 1.1-1.4) was at a compression pressure of 6 kPa, increasing to 2.9 (95% CI: 2.7-3.1) at 16 kPa. The mean pain score was 0.6 (95% CI: 0.4-0.6) at a compressed breast thickness of 20 mm, increasing to 2.9 (95% CI: 2.7-3.1) at 90 mm.

CONCLUSION

The mean pain score was low, 1.9 on NRS, for women screened with DBT. A compression force of 60-130 N and a pressure 6-16 kPa were associated with no or mild pain.

Mechanical standardisation of mammographic compression using Volpara software

INTRODUCTION

Although breast compression is required in routine mammographic practices, current subjective protocols enforcing 'breast tautness' have minimal clinical reproducibility. Whilst objective guidelines of target force (daN) do not consider breast volumes, new measures of pressure (kPa) account for associated variations. The study aims to determine characteristic compressive forces applied at an Australian diagnostic breast clinic, thereby establishing performance success in achieving ideal pressures of 10 kPa.

METHODS

Parameters of 1972 mammograms were analysed retrospectively from a South Australian diagnostic breast clinic. Raw data were processed using VolparaDensity software; applied compression (force/pressure), breast thickness, breast volume, breast density and average glandular dose estimates were investigated based on breast/paddle contact areas.

RESULTS

Distributions of applied average forces is large, yet distributions of applied average pressures are larger; this is internationally comparable. Regarding force-compressions, 98.6% are >5 daN, 16.6% are >10 daN, and 0.0% are >15 daN. Regarding pressure-compressions, 94.5% are >5 kPa, 36.0% are >10 kPa, and 6.3% are >15 kPa. Measures of average breast thickness, volume and density show anatomically consistent trends, with average glandular dose values constant, albeit high.

CONCLUSIONS

There was a high level of variation of applied compression forces in relation to breast/paddle contact area and an even higher variation in applied pressure. This is comparable with existing literature. Real-time compression pressure standardisation may benefit examination consistency. The relationship between breast volume, contact area, compression force and resultant compression pressure may aid in developing an objective compression protocol for clinical practice.

IMPLICATIONS FOR PRACTICE

Practical guidelines may increase the reproducibility of image acquisition, whilst optimizing patient discomfort and additional radiation dose from image repeats. Patient compliance may increase in accordance with perceived advantages of mechanical standardisation, ultimately aiding in the detection of early-stage breast cancer.

Pressure-based Compression Guidance of the Breast in Digital Breast Tomosynthesis Using Flexible Paddles Compared to Conventional Compression

OBJECTIVE

We investigated the effect of introducing a pressure-based flexible paddle on compression parameters and user and patient experience of digital breast tomosynthesis (DBT) combined with patient-assisted compression or technologist compression.

METHODS

After institutional review board approval, women with a DBT appointment who gave informed consent received pressure-based flexible paddle breast compression. Eight lights on the paddle were illuminated (1.9 kPa per light) as pressure was applied, aiming for an 8-13.9 kPa target range. The compression level was applied by the technologist or the participant utilizing a remote control device. The participant's and technologist's experiences were assessed by a questionnaire. Compression parameters were compared to previous examinations. Comparative statistics were performed using t-tests.

RESULTS

Pressure-based compression (PBC) was judged to be similar or more comfortable compared with previous traditional exams (80%, 83/103), and 87% (90/103) of participants would recommend PBC to friends. Pressure variability decreased for craniocaudal (CC) views (-55%, P < 0.001) and mediolateral oblique (MLO) views (-34%, P < 0.0001). Subgroup analysis showed a similar glandular dose for CC views, while breast thickness was reduced (-3.74 mm, P < 0.0001). For MLO views, both glandular dose (-0.13 mGy, P < 0.0001) and breast thickness were reduced (-6.70 mm, P < 0.0001). Mean compression parameters were similar for technologist compression and patient-assisted examinations.

CONCLUSION

Use of the pressure-based flexible paddle in DBT, with or without patient-assisted compression, improved participant and technologist experience and reduced compression pressure variability, mean breast thickness, and glandular dose.

Mammographic compression practices of force- and pressure-standardisation protocol: A scoping review

INTRODUCTION

As an efficient, effective and moderately inexpensive modality, mammography has been implemented as a cancer screening tool and in diagnostic management. However, appropriate breast compression is necessary for optimal outcomes. Current key measures of compression force are subjective and variable, giving rise to the concept of a 'personalised' pressure-standardisation protocol.

METHODS

A scoping review of the literature was performed using the Arksey and O'Malley framework to explore the existing force- and pressure-standardisation protocols in clinical application. A comprehensive search strategy and standardised study selection and evaluation were completed. This synthesis of existing knowledge can lead to the implementation of mechanically standardised mammographic compression pressure as a feasible tailored approach to clinical practice. Four databases (PubMed, MEDLINE, Embase and Scopus) were searched from the databases' inception to 13 December 2019 for relevant information, and eighteen articles were selected for analysis.

RESULTS

In addition to current protocol comparison, emerging key concepts include the reasoning behind standardisation, the benefits of improved diagnostic outcomes/decreased pain with negligible change in image quality and average glandular dose (AGD), and the recommendation of a 10kPa (approximate) pressure-standardisation protocol. Research to date is largely based abroad (Netherlands), with a strong focus on screening practices. Consequently, several gaps in the current literature were identified as potential directions for future investigation.

CONCLUSIONS

As a suggested mammographic guideline, compression pressures of approximately 10kPa aid in image acquisition reproducibility both within and between women; pain levels decrease, with minimal variations to breast thickness, AGD and image quality.

Comparison of Qualitative and Volumetric Assessments of Breast Density and Analyses of Breast Compression Parameters and Breast Volume of Women in Bahcesehir Mammography Screening Project

Objective

We aimed to compare visual and quantitative measurements of breast density and to reveal the density profile with compression characteristics.

Materials and Methods

Screening mammograms of 1399 women between May 2014 and May 2015 were evaluated by using Volpara 4^th and 5^th version. First 379 mammograms were assessed according to ACR BI-RADS 4^th edition and compared to Volpara. We categorized the breast density in two subgroups as dens or non-dens. Two radiologists reviewed the images in consensus. Agreement level between visual and volumetric methods and volumetric methods between themselves assessed using weighted kappa statistics. Volpara data such as fibroglandular volume (FGV), breast volume (BV), compression thickness (CT), compression force (CF), compression pressure (CP) were also analyzed with relation to the age.

Results

1399 mammograms were distributed as follows: 12.7% VDG1, 39.3% VDG2, 34.1% VDG3, 13.9% VDG4 according to the 4th edition of Volpara; 1.2% VDG1, 46% VDG2, 36.8% VDG3, 15.9% VDG4 according to the 5^th edition of Volpara. The difference between two editions was 4.7% increase in dense category. 379 mammograms, according to ACR BI-RADS 4^th edition, were distributed as follows: 25.9% category A, 50.9% category B, 19.8% category C, 3.4% category D. The strength of agreement between the Volpara 4^th and 5^th editions was found substantial (k=0.726). The agreements between visual assessment and both Volpara editions were poor (k=-0.413, k=-0.399 respectively). There was a 142% increase in dense group with the VDG 4^th edition and 162% with the VDG 5^th edition when compared to visual assessment. Compression force decreased while compression pressure increased with increasing Volpara Density Grade (VDG) (p for trend <0.001 for both). Compression thickness and breast volume decreased with increasing VDG (p for trend <0.001 for both). The FGV decreases with age and the breast volume increases with increasing age (p<0.001).

Conclusion

Visual assessment of breast density doesn't correlate well with volumetric assessments. Obtaining additional information about physical parameters and breast profile by the results of quantified methods is important for breast cancer risk assessments and prevention strategies.

Breast compression parameters among women screened with standard digital mammography and digital breast tomosynthesis in a randomized controlled trial

Background

No evidence-based guidelines regarding optimal breast compression in mammography exist, neither for standard digital mammography nor for digital breast tomosynthesis.

Purpose

To compare breast compression parameters and mean glandular dose in a randomized controlled trial with digital mammography versus digital breast tomosynthesis.

Material and Methods

We used information from 21,729 women aged 50–69 years, who participated in the To-Be trial, as part of BreastScreen Norway, 2016–2017. Information was obtained from the DICOM header and by assessing the images in an automated software for density estimation (VolparaDensity). Using linear regression, we investigated the effect of screening technique on breast compression parameters; compression force (N), compression pressure (kPa), and compressed breast thickness (mm), and mean glandular dose (mGy), by view (craniocaudal [CC] and mediolateral oblique [MLO]). We adjusted for age, breast volume and fibroglandular volume.

Results

A total of 11,056 (50.9%) women were screened with digital mammography and 10,673 (49.1%) with digital breast tomosynthesis. Adjusted regression analysis showed that women undergoing digital mammography received higher compression forces than women undergoing digital breast tomosynthesis (CC: –4.7 N; MLO: –1.1 N, P < 0.001 for both), higher compression pressure (CC: –1.0 k Pa; MLO: –0.1 kPa, P < 0.001 for both), and higher values of compressed breast thickness in the MLO view (–0.3 mm, P = 0.02). The women undergoing digital mammography received a lower mean glandular dose than women undergoing digital breast tomosynthesis ([+]0.06 mGy, P < 0.001).

Conclusion

Women undergoing digital breast tomosynthesis received lower compression force, compression pressure, and compressed breast thickness in MLO view, compared to women undergoing digital mammography. Further studies should investigate the impact of breast compression on image quality, screening outcome, and radiation dose for digital mammography and digital breast tomosynthesis in order to establish evidence-based guidelines for breast compression.

Characterization of the imaging settings in screening mammography using a tracking and reporting system: A multi-center and multi-vendor analysis

A tracking and reporting system was developed to monitor radiation dose in X-ray breast imaging. We used our tracking system to characterize and compare the mammographic practices of five breast imaging centers located in the United States and Brazil. Clinical data were acquired using eight mammography systems comprising three modalities: computed radiography (CR), full-field digital mammography (FFDM), and digital breast tomosynthesis (DBT). Our database consists of metadata extracted from 334,234 images. We analyzed distributions and correlations of compressed breast thickness (CBT), compression force, target-filter combinations, X-ray tube voltage, and average glandular dose (AGD). AGD reference curves were calculated based on AGD distributions as a function of CBT. These curves represent an AGD reference for a particular population and system. Differences in AGD and imaging settings were attributed to a combination of factors, such as improvements in technology, imaging protocol, and patient demographics. The tracking system allows the comparison of various imaging settings used in screening mammography, as well as the tracking of patient- and population-specific breast data collected from different populations.

Preoperative assessment of contrast-enhanced spectral mammography of diagnosed breast cancers after sonographic biopsy: Correlation to contrast-enhanced magnetic resonance imaging and 5-year postoperative follow-up

To assess the feasibility of using contrast-enhanced spectral mammography (CESM) for operative planning of patients with breast cancers who were initially diagnosed by sonographic guided biopsy.With the approval of the Institutional Review Board of our hospital, we retrospectively reviewed the data on patients with breast cancers who underwent CESM and contrast-enhanced magnetic resonance imaging (CE-MRI) prior to operation and were followed up for at least 5 years postoperatively. The patients with breast cancer diagnosed by sonographic guided biopsy without mammography were included for analysis. The size and number of cancers on low-energy mammograms (LE-MG), recombined subtracted mammograms (RSM), and CE-MRI were recorded and compared with microscopic histopathologic data and at least 5 years of clinical follow-up data.Fifty-one cancerous breasts of 46 patients were included in the analysis. All the principal cancers could be detected by RSM or CE-MRI; however, only 45 were by LE-MG. The Pearson correlation coefficients for the size on microscopy were 0.44 for LE-MG, 0.77 for RSM, and 0.84 for CE-MRI (all P-values ≤.001). Regarding the microscopic reports, RSM or CE-MRI had sensitivities of 100% and a positive predictive value of 63.6% for multicentric cancers. One breast cancer with partial mastectomy recurred after 3 years of follow-up.CESM was feasible for assessing the cancer extension and multicentric cancers as secondary examination in patients with diagnosed breast cancers after sonographic biopsy.

Evaluation of pressure-controlled mammography compression paddles with respect to force-controlled compression paddles in clinical practice

Objectives

To reduce pain and discomfort associated with breast compression in mammography, a pressure-controlled compression paddle was recently introduced.

The objective was to evaluate the pressure-controlled paddle by comparing it to the standard force-controlled paddle.

Methods

Differences of compressed breast thickness (CBT), compression force, compression pressure, and average glandular dose (AGD) between annual follow-up full-field digital mammography exams of 3188 patients were retrospectively examined. Two groups were compared: (1) force-force group (FF-group), both examinations were performed with the force-controlled paddle, and (2) force-pressure group (FP-group), only the follow-up examination was performed with the pressure-controlled paddle.

In an additional group of patients, pain scores on a scale of 0 (no pain at all) to 10 (worst pain imaginable) were evaluated prospectively (n = 343) who were randomly assigned to either paddle.

Results

Median differences between follow-up exams in CBT, compression force, compression pressure, and AGD were for the FF- and FP-group respectively − 1.0 vs 0.0 mm (p < 0.001); 0.0 vs − 1.0 daN (p = 0.002); − 1.0 vs − 0.5 kPa (p = 0.005); and 0.05 vs − 0.02 mGy (p < 0.001). These differences were, although statistically significant, clinically non-relevant (defined as ΔCBT > ± 2 mm; Δforce > ± 2 daN; Δpressure > ± 1 kPa and ΔAGD > ± 0.1 mGy). The subanalysis dividing CBT into five categories revealed similar results. The median [interquartile range] pain scores were 6 [3, 7] and 5 [3, 7] for the force-controlled and pressure-controlled paddle, respectively, which was not significantly different (p = 0.113).

Conclusions

We observed no clinically relevant differences in CBT, compression force, compression pressure, AGD, or pain score between the force- and pressure-controlled paddle. As such, we found no basis for preferring one paddle over the other.

Key Points

• The pressure-controlled paddle did not show any clinically relevant changes in breast compression parameters compared to the force-controlled paddle.

• The pressure-controlled paddle did not lead to significant reduction in pain scores indicated by the patients compared to the force-controlled paddle.

• A large variation in compression force and compression pressure was observed in mammography exams for the both the force- and pressure-controlled compression paddle.

Electronic supplementary material

The online version of this article (10.1007/s00330-018-5953-6) contains supplementary material, which is available to authorized users.