Comparing image quality of five breast tomosynthesis systems based on radiologists' reviews of phantom data

BACKGROUND

Previous studies have shown differences in technical image quality between digital breast tomosynthesis (DBT) systems. However, quantitative image quality measurements may not necessarily fully reflect the clinical performance of DBT.

PURPOSE

To study the subjective image quality of five DBT systems manufactured by Fujifilm, GE, Hologic, Planmed, and Siemens using phantom images.

MATERIAL AND METHODS

A TOR MAM test object with polymethyl methacrylate plates was imaged on five DBT systems from different vendors. Three DBT acquisitions were performed at mean glandular doses of 1.0 mGy, 2.0 mGy, and 3.5 mGy while maintaining a constant phantom set-up. Eight DBT acquisitions with different test plate positions and phantom set-up thicknesses were performed at clinically applied dose levels. Additionally, three conventional two-dimensional mammogram images were acquired with different phantom thicknesses. Six radiologists ranked the systems based on the visibilities of the targets seen in the phantom images.

RESULTS

In the DBT acquisitions performed at comparable dose levels, one system differed significantly from all other systems in microcalcification scores. When using site-specific DBT protocols, significant differences were found between the devices for microcalcification, filament, and low-contrast targets. A strong correlation was observed between the reviewer scores and radiation doses in DBT acquisitions, whereas no such correlation was observed in the 2D acquisitions.

CONCLUSION

In DBT acquisitions, dose level was found to be a major factor explaining image quality differences between the systems, regardless of other acquisition parameters. Most DBT systems performed equally well at similar dose levels.

Radiologists' performance in reading digital breast tomosynthesis with and without synthesized views for cancer detection

OBJECTIVE

The study aims to evaluate the diagnostic efficacy of radiologists and radiology trainees in digital breast tomosynthesis (DBT) alone vs DBT plus synthesized view (SV) for an understanding of the adequacy of DBT images to identify cancer lesions.

METHODS

Fifty-five observers (30 radiologists and 25 radiology trainees) participated in reading a set of 35 cases (15 cancer) with 28 readers reading DBT and 27 readers reading DBT plus SV. Two groups of readers had similar experience in interpreting mammograms. The performances of participants in each reading mode were compared with the ground truth and calculated in term of specificity, sensitivity, and ROC AUC. The cancer detection rate in various levels of breast density, lesion types and lesion sizes between 'DBT' and 'DBT + SV' were also analyzed. The difference in diagnostic accuracy of readers between two reading modes was assessed using Man-Whitney U test. p < 0.05 indicated a significant result.

RESULTS

There was no significant difference in specificity (0.67-vs-0.65; p = 0.69), sensitivity (0.77-vs-0.71; p = 0.09), ROC AUC (0.77-vs-0.73; p = 0.19) of radiologists reading DBT plus SV compared with radiologists reading DBT. Similar result was found in radiology trainees with no significant difference in specificity (0.70-vs-0.63; p = 0.29), sensitivity (0.44-vs-0.55; p = 0.19), ROC AUC (0.59-vs-0.62; p = 0.60) between two reading modes. Radiologists and trainees obtained similar results in two reading modes for cancer detection rate with different levels of breast density, cancer types and sizes of lesions (p > 0.05).

CONCLUSION

Findings show that the diagnostic performances of radiologists and radiology trainees in DBT alone and DBT plus SV were equivalent in identifying cancer and normal cases.

ADVANCES IN KNOWLEDGE

DBT alone had equivalent diagnostic accuracy as DBT plus SV which could imply the consideration of using DBT as a sole modality without SV.

Ensuring Clarity and Understandability of the FDA's Breast Density Notifications

This Viewpoint discusses the use of breast density notifications to inform women with dense breast tissue of the potential need for supplemental cancer screening, as well as the need to ensure that such notifications are clear and understandable to women of all language backgrounds, literacy levels, educational levels, and socioeconomic backgrounds.

Imaging and pathological discordance amongst the plethora of breast lesions in breast biopsies

INTRODUCTION

Imaging-guided breast tissue biopsy has become an acceptable alternative to open surgical biopsy for nonpalpable breast lesions. Discussion of abnormal results of the correlation between imaging and pathological findings can be very challenging as it can assist in decision-making with regard to the further treatment options by arriving at a comprehensive diagnosis.

MATERIALS AND METHODS

This was a retrospective study. Radiological data from imaging-guided breast biopsies of 500 patients during a 6-year period was collected and classified by a specialist radiologist as per the BI-RADS format. Histopathology reports were studied and discordance analyzed.

RESULTS

A total of 500 cases were reviewed. Approximately 33% (168) cases fell into the BI-RADS 3 category, 24.4% (122) into the BI-RADS 4, and 37% (187) into BI-RADS 5 categories. Approximately 50% (n = 250) cases were benign, 2.6% (13) belonged to the high-risk category, and 47.4% (237) were malignant. The number of discordant cases was 12 (2.4%), mostly due to technical factors. Sensitivity of biopsies to detect malignancy was 85%, specificity was 96%, and accuracy of biopsy in diagnosing cancer was 90%.

DISCUSSION

The "triple assessment" is the most sensitive method for detecting early breast cancer. An effective communication pathway must be established between a clinician, radiologist, and pathologist for surgical excision in discordance as it carries a high prevalence of carcinoma in these lesions.

CONCLUSION

In discordant cases, either due to abnormal results of imaging or of abnormal pathological findings, the final decision is based on two concordant findings, out of the three parameters. This involves a multidisciplinary breast conference and an active participation by the pathologist.

Adherence to guidance for prioritizing higher risk groups for breast cancer screening during the COVID-19 pandemic in the Ontario Breast Screening Program: a descriptive study

BACKGROUND

Breast cancer screening in Ontario, Canada, was deferred during the first wave of the COVID-19 pandemic, and a prioritization framework to resume services according to breast cancer risk was developed. The purpose of this study was to assess the impact of the pandemic within the Ontario Breast Screening Program (OBSP) by comparing total volumes of screening mammographic examinations and volumes of screening mammographic examinations with abnormal results before and during the pandemic, and to assess backlogs on the basis of adherence to the prioritization framework.

METHODS

A descriptive study was conducted among women aged 50 to 74 years at average risk and women aged 30 to 69 years at high risk, who participated in the OBSP. Percentage change was calculated by comparing observed monthly volumes of mammographic examinations from March 2020 to March 2021 with 2019 volumes and proportions by risk group. We plotted estimates of backlog volumes of mammographic examinations by risk group, comparing pandemic with prepandemic screening practices. Volumes of mammographic examinations with abnormal results were plotted by risk group.

RESULTS

Volumes of mammographic examinations in the OBSP showed the largest declines in April and May 2020 (> 99% decrease) and returned to prepandemic levels as of March 2021, with an accumulated backlog of 340 876 examinations. As of March 2021, prioritization had reduced the backlog volumes of screens for participants at high risk for breast cancer by 96.5% (186 v. 5469 expected) and annual rescreens for participants at average risk for breast cancer by 13.5% (62 432 v. 72 202 expected); there was a minimal decline for initial screens. Conversely, the backlog increased by 7.6% for biennial rescreens (221 674 v. 206 079 expected). More than half (59.4%) of mammographic examinations with abnormal results were for participants in the higher risk groups.

INTERPRETATION

Prioritizing screening for those at higher risk for breast cancer may increase diagnostic yield and redirect resources to minimize potential long-term harms caused by the pandemic. This further supports the clinical utility of risk-stratified cancer screening.

Determination of thresholds of risk in women at average risk of breast cancer to personalize the organized screening program

In France, more than 10 million women at "average" risk of breast cancer (BC), are included in the organized BC screening. Existing predictive models of BC risk are not adapted to the French population. Thus, we set up a new score in the French Hérault region and looked for subgroups at a graded level of risk in women at "average" risk. We recruited a retrospective cohort of women, aged 50 to 60, who underwent the organized BC screening, and included 2241 non-cancer women and 527 who developed a BC during a 12-year follow-up period (2006-2018). The risk factors identified were high breast density (ACR BI-RADS grading)(B vs A: HR = 1.41, 95%CI [1.05; 1.9], p = 0.023; C vs A: HR = 1.65 [1.2; 2.27], p = 0.02 ; D vs A: HR = 2.11 [1.25;3.58], p = 0.006), a history of maternal breast cancer (HR = 1.61 [1.24; 2.09], p < 0.001), and socioeconomic difficulties (HR 1.23 [1.09; 1.55], p = 0.003). While early menopause (HR = 0.36 [0.13; 0.99], p = 0.003) and an age at menarche after 12 years (HR = 0.77 [0.63; 0.95], p = 0.047) were protective factors. We identified 3 groups at risk: lower, average, and higher, respectively. A low threshold was characterized at 1.9% of 12-year risk and a high threshold at 4.5% 12-year risk. Mean 12-year risks in the 3 groups of risk were 1.37%, 2.68%, and 5.84%, respectively. Thus, 12% of women presented a level of risk different from the average risk group, corresponding to 600,000 women involved in the French organized BC screening, enabling to propose a new strategy to personalize the national BC screening. On one hand, for women at lower risk, we proposed to reduce the frequency of mammograms and on the other hand, for women at higher risk, we suggested intensifying surveillance.

Use of artificial intelligence for image analysis in breast cancer screening programmes: systematic review of test accuracy

OBJECTIVE

To examine the accuracy of artificial intelligence (AI) for the detection of breast cancer in mammography screening practice.

DESIGN

Systematic review of test accuracy studies.

DATA SOURCES

Medline, Embase, Web of Science, and Cochrane Database of Systematic Reviews from 1 January 2010 to 17 May 2021.

ELIGIBILITY CRITERIA

Studies reporting test accuracy of AI algorithms, alone or in combination with radiologists, to detect cancer in women's digital mammograms in screening practice, or in test sets. Reference standard was biopsy with histology or follow-up (for screen negative women). Outcomes included test accuracy and cancer type detected.

STUDY SELECTION AND SYNTHESIS

Two reviewers independently assessed articles for inclusion and assessed the methodological quality of included studies using the QUality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. A single reviewer extracted data, which were checked by a second reviewer. Narrative data synthesis was performed.

RESULTS

Twelve studies totalling 131 822 screened women were included. No prospective studies measuring test accuracy of AI in screening practice were found. Studies were of poor methodological quality. Three retrospective studies compared AI systems with the clinical decisions of the original radiologist, including 79 910 women, of whom 1878 had screen detected cancer or interval cancer within 12 months of screening. Thirty four (94%) of 36 AI systems evaluated in these studies were less accurate than a single radiologist, and all were less accurate than consensus of two or more radiologists. Five smaller studies (1086 women, 520 cancers) at high risk of bias and low generalisability to the clinical context reported that all five evaluated AI systems (as standalone to replace radiologist or as a reader aid) were more accurate than a single radiologist reading a test set in the laboratory. In three studies, AI used for triage screened out 53%, 45%, and 50% of women at low risk but also 10%, 4%, and 0% of cancers detected by radiologists.

CONCLUSIONS

Current evidence for AI does not yet allow judgement of its accuracy in breast cancer screening programmes, and it is unclear where on the clinical pathway AI might be of most benefit. AI systems are not sufficiently specific to replace radiologist double reading in screening programmes. Promising results in smaller studies are not replicated in larger studies. Prospective studies are required to measure the effect of AI in clinical practice. Such studies will require clear stopping rules to ensure that AI does not reduce programme specificity.

STUDY REGISTRATION

Protocol registered as PROSPERO CRD42020213590.

Evaluation of Adjunctive Ultrasonography for Breast Cancer Detection Among Women Aged 40-49 Years With Varying Breast Density Undergoing Screening Mammography: A Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

Mammography has limited accuracy in breast cancer screening. Ultrasonography, when used in conjunction with mammography screening, is helpful to detect early-stage and invasive cancers for asymptomatic women with dense and nondense breasts.

OBJECTIVE

To evaluate the performance of adjunctive ultrasonography with mammography for breast cancer screening, according to differences in breast density.

DESIGN, SETTING, AND PARTICIPANTS

This study is a secondary analysis of the Japan Strategic Anti-cancer Randomized Trial. Between July 2007 and March 2011, asymptomatic women aged 40 to 49 years were enrolled in Japan. The present study used data from cases enrolled from the screening center in Miyagi prefecture during 2007 to 2020. Participants were randomly assigned in a 1:1 ratio to undergo either mammography with ultrasonography (intervention group) or mammography alone (control group). Data analysis was performed from February to March 2020.

EXPOSURES

Ultrasonography adjunctive to mammography for breast cancer screening regardless of breast density.

MAIN OUTCOMES AND MEASURES

Sensitivity, specificity, recall rates, biopsy rates, and characteristics of screen-detected cancers and interval breast cancers were evaluated between study groups and for each modality according to breast density.

RESULTS

A total of 76 119 women were enrolled, and data for 19 213 women (mean [SD] age, 44.5 [2.8] years) from the Miyagi prefecture were analyzed; 9705 were randomized to the intervention group and 9508 were randomized to the control group. A total of 11 390 women (59.3%) had heterogeneously or extremely dense breasts. Among the overall group, 130 cancers were found. Sensitivity was significantly higher in the intervention group than the control group (93.2% [95% CI, 87.4%-99.0%] vs 66.7% [95% CI, 54.4%-78.9%]; P < .001). Similar trends were observed in women with dense breasts (sensitivity in intervention vs control groups, 93.2% [95% CI, 85.7%-100.0%] vs 70.6% [95% CI, 55.3%-85.9%]; P < .001) and nondense breasts (sensitivity in intervention vs control groups, 93.1% [95% CI, 83.9%-102.3%] vs 60.9% [95% CI, 40.9%-80.8%]; P < .001). The rate of interval cancers per 1000 screenings was lower in the intervention group compared with the control group (0.5 cancers [95% CI, 0.1-1.0 cancers] vs 2.0 cancers [95% CI, 1.1-2.9 cancers]; P = .004). Within the intervention group, the rate of invasive cancers detected by ultrasonography alone was significantly higher than that for mammography alone in both dense (82.4% [95% CI, 56.6%-96.2%] vs 41.7% [95% CI, 15.2%-72.3%]; P = .02) and nondense (85.7% [95% CI, 42.1%-99.6%] vs 25.0% [95% CI, 5.5%-57.2%]; P = .02) breasts. However, sensitivity of mammography or ultrasonography alone did not exceed 80% across all breast densities in the 2 groups. Compared with the control group, specificity was significantly lower in the intervention group (91.8% [95% CI, 91.2%-92.3%] vs 86.8% [95% CI, 86.2%-87.5%]; P < .001). Recall rates (13.8% [95% CI, 13.1%-14.5%] vs 8.6% [95% CI, 8.0%-9.1%]; P < .001) and biopsy rates (5.5% [95% CI, 5.1%-6.0%] vs 2.1% [95% CI, 1.8%-2.4%]; P < .001) were significantly higher in the intervention group than the control group.

CONCLUSIONS AND RELEVANCE

In this secondary analysis of a randomized clinical trial, screening mammography alone demonstrated low sensitivity, whereas adjunctive ultrasonography was associated with increased sensitivity. These findings suggest that adjunctive ultrasonography has the potential to improve detection of early-stage and invasive cancers across both dense and nondense breasts. Supplemental ultrasonography should be considered as an appropriate imaging modality for breast cancer screening in asymptomatic women aged 40 to 49 years regardless of breast density.

TRIAL REGISTRATION

NIPH Clinical Trial Identifier: UMIN000000757.

Evaluation of the quality of mammographic breast positioning: a quality improvement study

BACKGROUND

Although there are concerns that inadequate breast positioning in mammographic examinations may lead to cancers being missed, few studies have examined the quality of breast positioning, especially in the Canadian context. Our objective was to assess the quality of breast positioning in mammographic examinations in a Quebec-wide representative sample of technologists.

METHODS

This quality improvement study was part of a professional inspection launched by the Ordre des technologues en imagerie médicale, en radio-oncologie et en électrophysiologie médicale du Québec among its members. The inspection was conducted between May and July 2017 on a proportionate stratified random sample of all active technologists certified in mammography in Quebec. Each technologist provided images from 15 consecutive mammographic examinations they performed in the previous 6 months. The quality of positioning was then evaluated by senior technologists using a quality assessment tool specifically developed for this inspection. A technologist was deemed to have failed the professional inspection when at least 7 of the 15 mammographic examinations were scored as critical failures. Proportions were calculated accounting for sampling weights and correction for finite population.

RESULTS

Among the 520 technologists certified in mammography in Quebec, 76 technologists (14.6%) were randomly selected for the professional inspection and contributed images from 1127 mammographic examinations. Thirty-eight technologists (weighted percentage 50.3%, 95% confidence interval [CI] 37.6% to 63.0%) failed the professional inspection. Overall, 492 mammographic examinations (43.7%, 95% CI 38.6% to 48.8%) had at least 1 image scored as a critical failure.

INTERPRETATION

Half of the technologists performing mammographic examinations in Quebec who participated in this study failed the inspection, and a substantial proportion of their mammographic examinations demonstrated critical failures in breast positioning. Overall, our findings are concordant with those of previous studies and highlight the need for additional investigations assessing the quality of breast positioning in mammographic examinations in other jurisdictions.

Breast Cancer Screening: Common Questions and Answers

Breast cancer is the most common nonskin cancer in women and accounts for 30% of all new cancers in the United States. The highest incidence of breast cancer is in women 70 to 74 years of age. Numerous risk factors are associated with the development of breast cancer. A risk assessment tool can be used to determine individual risk and help guide screening decisions. The U.S. Preventive Services Task Force (USPSTF) and American Academy of Family Physicians (AAFP) recommend against teaching average-risk women to perform breast self-examinations. The USPSTF and AAFP recommend biennial screening mammography for average-risk women 50 to 74 years of age. However, there is no strong evidence supporting a net benefit of mammography screening in average-risk women 40 to 49 years of age; therefore, the USPSTF and AAFP recommend individualized decision-making in these women. For average-risk women 75 years and older, the USPSTF and AAFP conclude that there is insufficient evidence to recommend screening, but the American College of Obstetricians and Gynecologists and the American Cancer Society state that screening may continue depending on the woman's health status and life expectancy. Women at high risk of breast cancer may benefit from mammography starting at 30 years of age or earlier, with supplemental screening such as magnetic resonance imaging. Supplemental ultrasonography in women with dense breasts increases cancer detection but also false-positive results.

Screening for Breast Cancer

Among women, breast cancer is the most commonly diagnosed cancer and the leading cause of cancer-related death in the world. The purpose of this article is to review the evidence regarding breast cancer screening for average-risk women. The review primarily focuses on mammographic screening but also reviews clinical breast examinations, emerging screening technologies, and opportunities to build consensus. Wherever possible, the review relies on published systematic reviews, meta-analyses, and guidelines from three major societies (US Preventive Services Task Force, American College of Radiology, and the American Cancer Society) to reflect a range of evidence-based perspectives regarding mammographic screening.

Kinetic patterns of benign and malignant breast lesions on contrast enhanced digital mammogram

Purpose

To evaluate the kinetic patterns of benign and malignant breast lesions using contrast-enhanced digital mammogram (CEDM).

Methods

Women with suspicious breast lesions on mammography or ultrasound were enrolled. Single-view mediolateral oblique (MLO) CEDM of an affected breast was acquired at 2, 3, 4, 7, and 10 min after injection of contrast agent. Three readers visually and semi-quantitatively analyzed the enhancement of suspicious lesions. The kinetic pattern of each lesion was classified as persistent, plateau, or washout over two time intervals, 2–4 min and 2–10 min, by comparing the signal intensity at the first time interval with that at the second.

Results

There were 73 malignant and 75 benign lesions in 148 patients (mean age: 52 years). Benign and malignant breast lesions showed the highest signal intensity at 3 min and 2 min, respectively. Average areas under receiver operating characteristic (ROC) curve for diagnostic accuracy based on lesion enhancement at different time points were 0.73 at 2 min, 0.72 at 3 min, 0.69 at 4 min, 0.67 at 7 min, and 0.64 at 10 min. Diagnostic performance was significantly better at 2, 3, and 4 min than at 7 and 10 min (all p < 0.05). A washout kinetic pattern was significantly associated with malignant lesions at 2–4 min and 2–10 min frames according to two of the three readers’ interpretations (all p ≤ 0.001).

Conclusion

Applications of optimal time intervals and kinetic patterns show promise in differentiation of benign and malignant breast lesions on CEDM.

Effect of mammographic screening from age 40 years on breast cancer mortality (UK Age trial): final results of a randomised, controlled trial

BACKGROUND

The appropriate age range for breast cancer screening remains a matter of debate. We aimed to estimate the effect of mammographic screening at ages 40-48 years on breast cancer mortality.

METHODS

We did a randomised, controlled trial involving 23 breast screening units across Great Britain. We randomly assigned women aged 39-41 years, using individual randomisation, stratified by general practice, in a 1:2 ratio, to yearly mammographic screening from the year of inclusion in the trial up to and including the calendar year that they reached age 48 years (intervention group), or to standard care of no screening until the invitation to their first National Health Service Breast Screening Programme (NHSBSP) screen at approximately age 50 years (control group). Women in the intervention group were recruited by postal invitation. Women in the control group were unaware of the study. The primary endpoint was mortality from breast cancers (with breast cancer coded as the underlying cause of death) diagnosed during the intervention period, before the participant's first NHSBSP screen. To study the timing of the mortality effect, we analysed the results in different follow-up periods. Women were included in the primary comparison regardless of compliance with randomisation status (intention-to-treat analysis). This Article reports on long-term follow-up analysis. The trial is registered with the ISRCTN registry, ISRCTN24647151.

FINDINGS

160 921 women were recruited between Oct 14, 1990, and Sept 24, 1997. 53 883 women (33·5%) were randomly assigned to the intervention group and 106 953 (66·5%) to the control group. Between randomisation and Feb 28, 2017, women were followed up for a median of 22·8 years (IQR 21·8-24·0). We observed a significant reduction in breast cancer mortality at 10 years of follow-up, with 83 breast cancer deaths in the intervention group versus 219 in the control group (relative rate [RR] 0·75 [95% CI 0·58-0·97]; p=0·029). No significant reduction was observed thereafter, with 126 deaths versus 255 deaths occurring after more than 10 years of follow-up (RR 0·98 [0·79-1·22]; p=0·86).

INTERPRETATION

Yearly mammography before age 50 years, commencing at age 40 or 41 years, was associated with a relative reduction in breast cancer mortality, which was attenuated after 10 years, although the absolute reduction remained constant. Reducing the lower age limit for screening from 50 to 40 years could potentially reduce breast cancer mortality.

FUNDING

National Institute for Health Research Health Technology Assessment programme.

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.

Proposed diagnostic reference levels for general radiography and mammography in Japan

Diagnostic reference levels (DRLs 2015) in Japan were first published in 2017, on the Japan Network for Research and Information on Medical Exposures network. Medical facilities in Japan are now presumably reconsidering radiation doses at their facilities and approaching protection optimisation through the application of DRLs 2015. However, since more than 3 years have elapsed since publication, radiation doses received by patients in Japan may have diverged from DRLs 2015. We therefore undertook the present study. Based on our questionnaire survey implemented in 2017, we estimated the entrance skin dose (ESD) under general radiography fields and the mean glandular dose (MGD) under mammography, to compile a report on the doses received by patients under general radiography fields and mammography, and to propose new DRLs as replacements for DRLs 2015. Radiation doses under general radiography fields and mammography were estimated from the results of the 2017 questionnaire survey and applied to determine new DRLs at 75% values of dose distributions in general radiography fields and at 95% values of dose distributions in mammography. Among all the modes for general radiography fields and mammography, median ESD and MGD were significantly smaller with flat panel detector systems than with computed radiography systems. Comparison of the results with DRLs 2015 values showed a trend toward decreases in all imaging methods of the general radiography fields and mammography ranging from 5.0% (child chest radiography) to 31.7% (skull radiography). Moreover, responses showed that DRLs 2015 were recognised and used for comparison at many facilities. We have described the doses received by patients in general radiography fields and mammography in 2017 and proposed new DRLs as replacements for DRLs 2015. The DRLs we proposed for general radiography fields and mammography were determined to be lower than DRLs 2015 for all modes.

Monitoring and evaluation of breast cancer screening programmes: selecting candidate performance indicators

BACKGROUND

In the scope of the European Commission Initiative on Breast Cancer (ECIBC) the Monitoring and Evaluation (M&E) subgroup was tasked to identify breast cancer screening programme (BCSP) performance indicators, including their acceptable and desirable levels, which are associated with breast cancer (BC) mortality. This paper documents the methodology used for the indicator selection.

METHODS

The indicators were identified through a multi-stage process. First, a scoping review was conducted to identify existing performance indicators. Second, building on existing frameworks for making well-informed health care choices, a specific conceptual framework was developed to guide the indicator selection. Third, two group exercises including a rating and ranking survey were conducted for indicator selection using pre-determined criteria, such as: relevance, measurability, accurateness, ethics and understandability. The selected indicators were mapped onto a BC screening pathway developed by the M&E subgroup to illustrate the steps of BC screening common to all EU countries.

RESULTS

A total of 96 indicators were identified from an initial list of 1325 indicators. After removing redundant and irrelevant indicators and adding those missing, 39 candidate indicators underwent the rating and ranking exercise. Based on the results, the M&E subgroup selected 13 indicators: screening coverage, participation rate, recall rate, breast cancer detection rate, invasive breast cancer detection rate, cancers > 20 mm, cancers ≤10 mm, lymph node status, interval cancer rate, episode sensitivity, time interval between screening and first treatment, benign open surgical biopsy rate, and mastectomy rate.

CONCLUSION

This systematic approach led to the identification of 13 BCSP candidate performance indicators to be further evaluated for their association with BC mortality.

Mammography diagnostic reference levels in Western Australia

Mammography dose data has been collected from Western Australian units to establish Diagnostic Reference Levels for the state. Reference levels have been determined for a variety of phantom thicknesses for both full field digital mammography units and digital breast tomosynthesis units. Levels for the American College of Radiology (ACR) Phantom have been established as 1.3 mGy and 1.5 mGy mean glandular dose for full field digital mammography and digital breast tomosynthesis respectively. 2 cm PMMA was 0.9 mGy and 1.0 mGy and 6 cm PMMA had values of 2.0 mGy and 2.3 mGy. This data can be utilised to help establish national reference levels in the future.

Screening Performance of Digital Breast Tomosynthesis vs Digital Mammography in Community Practice by Patient Age, Screening Round, and Breast Density

Importance

Digital mammography (DM) and digital breast tomosynthesis (DBT) are used for routine breast cancer screening. There is minimal evidence on performance outcomes by age, screening round, and breast density in community practice.

Objective

To compare DM vs DBT performance by age, baseline vs subsequent screening round, and breast density category.

Design, Setting, and Participants

This comparative effectiveness study assessed 1 584 079 screening examinations of women aged 40 to 79 years without prior history of breast cancer, mastectomy, or breast augmentation undergoing screening mammography at 46 participating Breast Cancer Surveillance Consortium facilities from January 2010 to April 2018.

Exposures

Age, Breast Imaging Reporting and Data System breast density category, screening round, and modality.

Main Outcomes and Measures

Absolute rates and relative risks (RRs) of screening recall and cancer detection.

Results

Of 1 273 492 DM and 310 587 DBT examinations analyzed, 1 028 891 examinations (65.0%) were of white non-Hispanic women; 399 952 women (25.2%) were younger than 50 years; and 671 136 women (42.4%) had heterogeneously dense or extremely dense breasts. Adjusted differences in DM vs DBT performance were largest on baseline examinations: for example, per 1000 baseline examinations in women ages 50 to 59, recall rates decreased from 241 examinations for DM to 204 examinations for DBT (RR, 0.84; 95% CI, 0.73-0.98), and cancer detection rates increased from 5.9 with DM to 8.8 with DBT (RR, 1.50; 95% CI, 1.10-2.08). On subsequent examinations, women aged 40 to 79 years with heterogeneously dense breasts had improved recall rates and improved cancer detection with DBT. For example, per 1000 examinations in women aged 50 to 59 years, the number of recall examinations decreased from 102 with DM to 93 with DBT (RR, 0.91; 95% CI, 0.84-0.98), and cancer detection increased from 3.7 with DM to 5.3 with DBT (RR, 1.42; 95% CI, 1.23-1.64). Women aged 50 to 79 years with scattered fibroglandular density also had improved recall and cancer detection rates with DBT. Women aged 40 to 49 years with scattered fibroglandular density and women aged 50 to 79 years with almost entirely fatty breasts benefited from improved recall rates without change in cancer detection rates. No improvements in recall or cancer detection rates were observed in women with extremely dense breasts on subsequent examinations for any age group.

Conclusions and Relevance

This study found that improvements in recall and cancer detection rates with DBT were greatest on baseline mammograms. On subsequent screening mammograms, the benefits of DBT varied by age and breast density. Women with extremely dense breasts did not benefit from improved recall or cancer detection with DBT on subsequent screening rounds.

Stand-Alone Artificial Intelligence for Breast Cancer Detection in Mammography: Comparison With 101 Radiologists

BACKGROUND

Artificial intelligence (AI) systems performing at radiologist-like levels in the evaluation of digital mammography (DM) would improve breast cancer screening accuracy and efficiency. We aimed to compare the stand-alone performance of an AI system to that of radiologists in detecting breast cancer in DM.

METHODS

Nine multi-reader, multi-case study datasets previously used for different research purposes in seven countries were collected. Each dataset consisted of DM exams acquired with systems from four different vendors, multiple radiologists' assessments per exam, and ground truth verified by histopathological analysis or follow-up, yielding a total of 2652 exams (653 malignant) and interpretations by 101 radiologists (28 296 independent interpretations). An AI system analyzed these exams yielding a level of suspicion of cancer present between 1 and 10. The detection performance between the radiologists and the AI system was compared using a noninferiority null hypothesis at a margin of 0.05.

RESULTS

The performance of the AI system was statistically noninferior to that of the average of the 101 radiologists. The AI system had a 0.840 (95% confidence interval [CI] = 0.820 to 0.860) area under the ROC curve and the average of the radiologists was 0.814 (95% CI = 0.787 to 0.841) (difference 95% CI = -0.003 to 0.055). The AI system had an AUC higher than 61.4% of the radiologists.

CONCLUSIONS

The evaluated AI system achieved a cancer detection accuracy comparable to an average breast radiologist in this retrospective setting. Although promising, the performance and impact of such a system in a screening setting needs further investigation.

Accuracy and Effectiveness of Mammography versus Mammography and Tomosynthesis for Population-Based Breast Cancer Screening: A Systematic Review and Meta-Analysis

We proposed to compare the accuracy and effectiveness of digital breast tomosynthesis (DBT), plus digital or synthetic mammography, with digital mammography alone in women attending population-based breast cancer screenings. We performed a systematic review and included controlled studies comparing DBT with digital mammography for breast cancer screening. Search strategies were applied to the MEDLINE, Embase, LILACS, and CENTRAL databases. With moderate quality of evidence, in 1,000 screens, DBT plus digital mammography increased the overall and invasive breast cancer rates by 3 and 2 (RR 1.36, 95% CI 1.18 to 1.58 and RR 1.51, 95% CI 1.27 to 1.79, respectively). DBT plus synthetic mammography increased both overall and invasive breast cancer rates by 2 (RR 1.38, 95% CI 1.24 to 1.54 and RR 1.37, 95% CI 1.22 to 1.55, respectively). DBT did not improve recall, false positive and false negative rates. However due to heterogeneity the quality of evidence was low. For women attending population-based breast cancer screenings, DBT increases rates of overall and invasive breast cancer. There is no evidence with high or moderate quality showing that DBT compared with digital mammography decreases recall rates, as well as false positive and false negative rates.

A survey of Canadian breast health professionals’ recommendations for high-risk benign breast disease

Summary

The management of high-risk benign breast disease (BBD) is changing because of improvements in radiological and pathological analysis. We sought to determine the current practice recommendations of breast health professionals in managing patients with high-risk BBD. We surveyed members of the Canadian Society of Surgical Oncology, Canadian Association of General Surgeons and Canadian Association of Radiologists. The survey contained demographic and case-based questions concerning management of high-risk benign breast lesions. Participants were asked for their recommendations and opinions regarding future risk of breast cancer as well as the role of chemoprevention. There was no consistency among the 41 respondents in the treatment recommendations for any of the high-risk benign conditions, and the lifetime risk associated with classic lobular carcinoma in situ was vastly underestimated. Education and evidenced-based guidelines are urgently needed to ensure more uniform practice nationally.

Provision of Italian diagnostic reference levels for diagnostic and interventional radiology

OBJECTIVES

The diagnostic reference level (DRL) is a useful tool for the optimisation of medical exposures. Thus, a Working Party coordinated by the Italian National Institute of Health and the National Workers Compensation Authority has been formed to provide Italian DRLs, for both diagnostic and interventional procedures, to be used as appropriate for the implementation of the 2013/59 European Directive into the national regulation.

MATERIALS AND METHODS

The multidisciplinary Working Party was formed by professionals involved in diagnostic and interventional radiology medical exposures and started from a critical revision of both the literature and the results of previous Italian surveys. The procedures were divided into five sections for adult (projection radiography, mammography, diagnostic fluoroscopy, CT and interventional radiology) and two sections for paediatric patients (projection radiography and CT). The provided DRL values have been identified for "normal" adult patients and for age-classes of paediatric patients.

RESULTS

Some of the DRL values provided by the Working Party are reported in this study as an example, divided by adult/paediatric patients, radiological technique and examination: specifically, DRLs for new radiological practices and new dose quantities as DRLs metric were introduced. The median value (rather than the mean) for each procedure, derived from a sample of patients, has to be compared with the corresponding DRL value, and dosimetric data related to a minimum number of patients should be collected for each examination.

CONCLUSIONS

The approach to the definition and use of DRLs through guidelines of national Authorities in collaboration with scientific Associations should simplify the periodical updating and could be useful for keeping the optimisation of medical exposures faithful to the development of radiological practice.

Importance of quality in breast cancer screening practice - a natural experiment in Alberta, Canada

OBJECTIVES

Regular breast cancer screening is a widely used cancer prevention strategy. Important quality indicators of screening include cancer detection rate, false positive rate, benign biopsy rate and post-screen invasive cancer rate. We compared quality indicators of community radiology clinics to those of 'Screen Test', which feature centralised batch reading and quality control processes. Both types of providers operated under a single provincial Breast Cancer Screening Programme.

SETTING

Community radiology clinics are operated by independent fee-for-service radiologists serving large and small communities throughout the Canadian province of Alberta. Launched by the provincial cancer agency, the Screen Test operates two physical clinics serving metropolises and mobile units serving remote regions. Eligible women may self-refer to any provider for screening mammography.

PARTICIPANTS

Women aged 50 to 69 years who had at least one screening mammogram between July 2006 and June 2010 in Alberta were included. Women with missing health region information or prior breast cancer diagnosis were excluded.

RESULTS

A total of 389 788 screening mammograms were analysed, of which 12.7% were performed by Screen Test. Compared with Screen Test during 2006 to 2008, community radiology clinics had a lower cancer detection rate (3.6 vs 4.6 per 1000 screens, risk ratio (RR): 0.81, 95% CI: 0.67 to 0.98) and a much higher false positive rate (9.4% vs 3.4%, RR: 2.72, 95% CI: 2.55 to 2.90). Most other performance indicators were also better in Screen Test overall and across all health regions. These performance indicators were similar during 2008 to 2010, showing no improvement with time.

CONCLUSIONS

Screen Test has a quality assurance process in place and performed significantly better. This provides empirical evidence of the effectiveness of a quality assurance process and may explain some of the large differences in breast cancer screening indicators between provinces and countries with formal programmes and those without.

International evaluation of an AI system for breast cancer screening

Screening mammography aims to identify breast cancer at earlier stages of the disease, when treatment can be more successful1. Despite the existence of screening programmes worldwide, the interpretation of mammograms is affected by high rates of false positives and false negatives2. Here we present an artificial intelligence (AI) system that is capable of surpassing human experts in breast cancer prediction. To assess its performance in the clinical setting, we curated a large representative dataset from the UK and a large enriched dataset from the USA. We show an absolute reduction of 5.7% and 1.2% (USA and UK) in false positives and 9.4% and 2.7% in false negatives. We provide evidence of the ability of the system to generalize from the UK to the USA. In an independent study of six radiologists, the AI system outperformed all of the human readers: the area under the receiver operating characteristic curve (AUC-ROC) for the AI system was greater than the AUC-ROC for the average radiologist by an absolute margin of 11.5%. We ran a simulation in which the AI system participated in the double-reading process that is used in the UK, and found that the AI system maintained non-inferior performance and reduced the workload of the second reader by 88%. This robust assessment of the AI system paves the way for clinical trials to improve the accuracy and efficiency of breast cancer screening.

APPLICATION OF THE EUROPEAN PROTOCOL IN THE EVALUATION OF DIGITAL MAMMOGRAPHY UNITS WITH TUNGSTEN TARGET TUBES

The performance of the first direct digital mammography unit in Gozo General Hospital, the Hologic Selenia Dimensions 2D, was assessed by applying the European Protocol for quality control in mammography screening. This system employs a Tungsten anode in association with a Rhodium or Silver filter, depending on the compressed breast thickness. The objective of this article was to apply the European Protocol in the evaluation of this system in terms of dose, image quality and detector performance and determine whether this system is suitable for use in the national breast-screening program.

Screening Mammography for Average-Risk Women: The Controversy and NCCN's Position

Breast cancer remains the most common nonskin cancer among women and a leading cause of morbidity and mortality. Early detection through screening and advances in treatment have contributed to a 39% mortality reduction in the United States since 1990. The NCCN Guidelines for Breast Cancer Screening and Diagnosis recommend annual mammographic screening for average-risk women beginning at age 40 years. Mammographic screening and subsequent treatment reduces breast cancer mortality based on a wide range of studies. This article highlights NCCN's position on screening mammography and the screening controversy.

Diagnosis and Management of High-Risk Breast Lesions

Atypical hyperplasia (AH) and lobular carcinoma in situ (LCIS) are nonmalignant breast lesions that confer a 4- to 10-fold increased risk for breast cancer in women. Often, AH and LCIS are diagnosed through breast biopsy due to a mammographic or palpable finding. Although AH and LCIS are benign breast disease, further management is necessary due to their high-risk nature and premalignant potential. Over the decades, management of AH and LCIS has changed as more is learned about these disease processes. This review explores the studies evaluating the risk for breast cancer in women with AH or LCIS and the clinical management of these lesions, which can include a combination of surgical excision, surveillance, and risk-reduction therapy.

A comparison of stereotactic and tomosynthesis-guided localisation of impalpable breast lesions

INTRODUCTION

Impalpable breast cancers require precise pre-operative lesion localisation to minimise re-excision rates. Conventional techniques include hookwire insertion using stereotactic guidance. Newer techniques include the use of tomosynthesis guidance and the use of iodine-125 seeds. This study compares the accuracy of lesion localisation with hookwire or seed insertion using prone stereotactic or upright tomosynthesis guidance.

METHODS

This registered quality improvement activity did not require formal ethics approval. The post-localisation images for 116 lesions were reviewed. The distance from the lesion or breast biopsy marker to the hookwire or seed was measured on post-insertion mammograms. The relative placement accuracy of hookwire or seed using prone stereotactic or upright tomosynthesis guidance was compared. A lesion to seed or wire distance > 10 mm was considered technically unsatisfactory.

RESULTS

94.8% of the seeds and wires inserted via prone stereotactic guidance were accurately placed, compared with 89.6% of those inserted via upright tomosynthesis. There were twice as many technically unsatisfactory insertions under upright tomosynthesis guidance. The majority of the unsatisfactory insertions using upright tomosynthesis occurred when the lesion was at or below the level of the nipple and the insertion was performed craniocaudally.

CONCLUSION

The degree of accuracy of pre-operative localisation of impalpable breast lesions is significantly higher with the use of prone stereotactic rather than upright tomosynthesis guidance. This was most evident with the placement of I-125 seeds, and in cases where the target lesion was located below the level of the nipple.

[Digital Breast Tomosynthesis Mammography System Registration Application Data Technical Review Concerns]

In this paper, the focus of technical review of the registration application data of digital Breast Tomosynthesis Mammography System was sorted out, so as to provide reference for researchers and manufacturers in China when applying for registration and preparation of such products.

Preparing for EQUIP by Measuring Mammography Image Quality

PURPOSE

To determine the feasibility of objectively critiquing mammography images and quantitatively assessing technologist performance, and to determine whether results can be compared to analyze performance.

METHODS

The authors assessed mammography examinations performed by 3 experienced technologists using a quality improvement method to track factors that affect image quality. A total of 147 examinations were evaluated prior to the technologists receiving standardized positioning training, and an equal number of examinations were evaluated 2 months after the training. During the evaluations, data was collected that described the quality of the examinations and the technologists' behavior during the pre-exposure, acquisition, and postexposure process that affected image quality.

RESULTS

The authors selected 7 out of more than 140 prominent examples to demonstrate a methodology to evaluate image quality, to use the results to empower the technologist to improve their performance in areas that indicate positioning and compression weakness, and to track the technologist's improvement over time. Technologist 1 demonstrated the most dramatic improvement between the pre- and posteducational evaluations in the length of the pectoral muscle on the mediolateral oblique projection. Technologist 3 improved inclusion of the inframammary fold region by 18% between evaluations. Posteducational evaluations also demonstrated a decrease in the percent of examinations that passed posterior nipple line measurements. Compression force did not significantly change.

DISCUSSION

Identifying specific technologist actions that positively or negatively affect the quality of mammography examinations and then providing this information to the technologist with a suggested plan of corrective action can improve mammography service.

CONCLUSION

This clinical validation study for mammography quality improvement demonstrated that technologist performance affecting image quality can be measured when examination and threshold variables are controlled.

Impact of full field digital mammography diagnosis for female patients with breast cancer

BACKGROUND

Previous clinical studies have reported that full field digital mammography (FFDM) can be used for diagnosis on breast cancer (BC) with promising outcome results. However, no study systematically investigates its diagnostic impact on female patients with BC. Thus, this systematic review will assess the accurate of FFDM diagnosis on BC.

METHODS

In this study, we will perform a comprehensive search strategy in the databases as follows: Cochrane Library, EMBASE, MEDILINE, PSYCINFO, Web of Science, Cumulative Index to Nursing and Allied Health Literature, Allied and Complementary Medicine Database, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, VIP Information, and Wanfang Data from inception to February 28, 2019. All case-controlled studies exploring the impacts of FFDM diagnosis for patients BC will be fully considered for inclusion in this study. Two authors will independently scan the title and abstracts for relevance, and assess full texts for inclusion. They will also independently extract data and will assess methodological qualify for each included study by using Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. RevMan V.5.3 software (London, UK) and Stata V.12.0 software (Texas, USA) will be used to pool the data and to conduct the meta-analysis.

RESULTS

The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio of FFDM will be used to determine the diagnostic accuracy of FFDM for the diagnosis of patients with BC.

CONCLUSION

Its findings will provide latest evidence for the diagnostic accuracy of FFDM in female patients with BC.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019125338.

Improving Mammography Quality Through EQUIP

On January 1, 2017, the U.S. Food and Drug Administration launched an initiative to improve mammography image quality. This initiative, called the Enhancing Quality Using the Inspection Program, or EQUIP, entails a series of questions that have become part of annual mammography facility inspections required under the Mammography Quality Standards Act. This article examines the EQUIP initiative, discusses the initiative's early results, and explores the criteria for quality mammography images, with a focus on optimal positioning and compression.

Automated daily quality control analysis for mammography in a multi-unit imaging center

BACKGROUND

The high requirements for mammography image quality necessitate a systematic quality assurance process. Digital imaging allows automation of the image quality analysis, which can potentially improve repeatability and objectivity compared to a visual evaluation made by the users.

PURPOSE

To develop an automatic image quality analysis software for daily mammography quality control in a multi-unit imaging center.

MATERIAL AND METHODS

An automated image quality analysis software using the discrete wavelet transform and multiresolution analysis was developed for the American College of Radiology accreditation phantom. The software was validated by analyzing 60 randomly selected phantom images from six mammography systems and 20 phantom images with different dose levels from one mammography system. The results were compared to a visual analysis made by four reviewers. Additionally, long-term image quality trends of a full-field digital mammography system and a computed radiography mammography system were investigated.

RESULTS

The automated software produced feature detection levels comparable to visual analysis. The agreement was good in the case of fibers, while the software detected somewhat more microcalcifications and characteristic masses. Long-term follow-up via a quality assurance web portal demonstrated the feasibility of using the software for monitoring the performance of mammography systems in a multi-unit imaging center.

CONCLUSION

Automated image quality analysis enables monitoring the performance of digital mammography systems in an efficient, centralized manner.

Validity of Using Accreditation Phantom in Quality Control of Digital Tomosynthesis

AIM

This study was undertaken to compare the two image-quality phantoms commonly used in full-field digital mammography (FFDM) and digital breast tomosynthesis (DBT) imaging.

METHODS

Mammography units with two targets and three filters resulting in three possible target/filter combinations and two kVp values which are widely used (28 and 32) were used for the comparison. The automatic exposure control system was used in combination with the selected kVp. The CIRS 15 mammographic accreditation phantom (MAP) and CIRS 20 (BR3D) breast imaging phantom were used with the three target/filter combinations and two kVp values. A total of 24 images were acquired and evaluated. Image score was determined as the smallest sized object detectable. The data were analyzed by using Mann-Whitney test.

RESULTS

There were significant (p<0.001) differences between the detectability of fibers present in the two phantoms, but there were no differences in the detectability of specks.

CONCLUSION

The finding in FFDM and DBT showed there were significant differences between the two phantoms (p<0.02) in fibers and specks visibility. The CIRS 20 phantom provided greater visibility of smaller structures, while the MAP was more suitable for assessing image quality of both FFDM and DBT imaging systems.

Evaluation of Digital Breast Tomosynthesis as Replacement of Full-Field Digital Mammography Using an In Silico Imaging Trial

IMPORTANCE

Expensive and lengthy clinical trials can delay regulatory evaluation of innovative technologies, affecting patient access to high-quality medical products. Simulation is increasingly being used in product development but rarely in regulatory applications.

OBJECTIVES

To conduct a computer-simulated imaging trial evaluating digital breast tomosynthesis (DBT) as a replacement for digital mammography (DM) and to compare the results with a comparative clinical trial.

DESIGN, SETTING, AND PARTICIPANTS

The simulated Virtual Imaging Clinical Trial for Regulatory Evaluation (VICTRE) trial was designed to replicate a clinical trial that used human patients and radiologists. Images obtained with in silico versions of DM and DBT systems via fast Monte Carlo x-ray transport were interpreted by a computational reader detecting the presence of lesions. A total of 2986 synthetic image-based virtual patients with breast sizes and radiographic densities representative of a screening population and compressed thicknesses from 3.5 to 6 cm were generated using an analytic approach in which anatomical structures are randomly created within a predefined breast volume and compressed in the craniocaudal orientation. A positive cohort contained a digitally inserted microcalcification cluster or spiculated mass.

MAIN OUTCOMES AND MEASURES

The trial end point was the difference in area under the receiver operating characteristic curve between modalities for lesion detection. The trial was sized for an SE of 0.01 in the change in area under the curve (AUC), half the uncertainty in the comparative clinical trial.

RESULTS

In this trial, computational readers analyzed 31 055 DM and 27 960 DBT cases from 2986 virtual patients with the following Breast Imaging Reporting and Data System densities: 286 (9.6%) extremely dense, 1200 (40.2%) heterogeneously dense, 1200 (40.2%) scattered fibroglandular densities, and 300 (10.0%) almost entirely fat. The mean (SE) change in AUC was 0.0587 (0.0062) (P < .001) in favor of DBT. The change in AUC was larger for masses (mean [SE], 0.0903 [0.008]) than for calcifications (mean [SE], 0.0268 [0.004]), which was consistent with the findings of the comparative trial (mean [SE], 0.065 [0.017] for masses and -0.047 [0.032] for calcifications).

CONCLUSIONS AND RELEVANCE

The results of the simulated VICTRE trial are consistent with the performance seen in the comparative trial. While further research is needed to assess the generalizability of these findings, in silico imaging trials represent a viable source of regulatory evidence for imaging devices.

PHYSICAL CHARACTERISATION OF FOUR DIFFERENT COMMERCIAL DIGITAL BREAST TOMOSYNTHESIS SYSTEMS

The aim of this article was to characterise the performance of four different digital breast tomosynthesis (DBT) systems in terms of dose and image quality parameters. One of them, GE Pristina, has never been tested before. Average glandular doses were measured both in DBT and 2D full field digital mammography mode. Several phantoms were employed to perform signal difference to noise ratio, slice sensitivity profile, slice to slice incrementation, chest wall offset, z-axis geometry, artefact spread function, low contrast detectability, contrast detail evaluations, image uniformity and in-plane MTF in chest wall-nipple and in tube-travel directions. There are many differences in DBT systems explored: the angular range, detector type, reconstruction algorithms, and the presence or not of the grid. Even if it is not simple to calculate a global figure of merit, the analysis of all the collected data can be useful in a contest of a quality assurance program to define a set of values that could be used as benchmarks.

Inter-Observer Variability in the Interpretation of Mammograms

Inter-observer agreement was tested in the interpretation by 8 radiologists of mammograms from 45 women (for a total of 180 films per radiologist). The radiologists were representative of the whole range of those involved in mammography in the town of Torino, with a number of films read per year ranging from 100 to 4000. Out of the 45, 9 women were affected by breast cancer (histologically proved), 25 had benign disease (diagnosed with fine-needle aspiration) and 11 had normal breasts. Weighted kappa values were in the range 0.27–0.82 (median 0.60) for parenchymal patterns; 0.33–0.67 (0.48) for diagnosis in five categories; and 0.22–0.57 (0.38) for indications for further diagnostic tests. These values are comparable with those reported from other investigations.

Quality Control of Mammography Screening in the Veneto Region. Evaluation of Four Programs at a Local Health Unit Level - Analysis of the Frequency and Diagnostic Pattern of Interval Cancers

AIMS AND BACKGROUND

Service mammography screening has been reported to have suboptimal performance compared to controlled trials. The aim of this study was to evaluate the sensitivity of the mammography screening program in four Local Health Units (ASL) and the possible causes of diagnostic error in cases further surfacing as interval cancers.

MATERIAL AND METHODS

Interval cancers were identified by cross checking of screened women databases with hospital discharge records reporting breast cancer. Proportional interval cancer incidence (observed interval cancers/expected invasive cancers) was determined by matching the database of women screened during 1999-2002 to the hospital discharge records databases during 1999-2003. The ratio of observed interval cancer rate to underlying incidence was compared to international standards and with literature data. Screening mammograms reported as negative and followed by interval cancers were randomly mixed with true-negative controls, and the resulting set underwent blind review by an external radiologist who applied the conventional criteria recommended for the classification of the type of diagnostic error (occult, minimal signs, screening error).

RESULTS

Matching of screening archives with the hospital discharge records databases allowed for the identification of 154 invasive interval cancers compared to 480 expected. The proportional observed/expected interval cancer incidence in the first and second year of the interval was 21% and 46%, respectively (ASL 1 = 14% or 38%, ASL 2 = 19% or 48%, ASL 3 = 30% or 53%, ASL 4 = 25% or 49%). Radiological review included 38 further interval cancer cases, identified after the time limits defined for proportional interval cancer incidence assessment, and could not include 18 interval cancers, not retrieved from ASL 4 archives: overall, 174 interval cancers were reviewed, of which 135 were classified as occult (77.3%) (ASL 1 = 83.3%, ASL 2 = 71.1%, ASL 3 = 78.6%, ASL 4 = 75%), 12 (6.9%) as minimal signs (ASL 1 = 6.6%, ASL 2 = 11.5%, ASL 3 = 2.4%, ASL 4 = 5%), and 27 (15.5%) as screening error (ASL 1 = 8.3%, ASL 2 = 17.3%, ASL 3 = 19.0%, ASL 4 = 25%).

CONCLUSIONS

Observed proportional interval cancer incidence was lower than commonly reported for service screening programs and currently recommended (< 30% in the first, < 50% in the second year of the interval). The analysis of interval cancer causes showed a screening error rate below the maximum acceptable standard (< 20% of interval cancers should be classified as screening error) in three of four programs and in average figures. Substantial differences observed among single programs (one did not comply to recommended standards) suggest that space is available for the improvement of overall performance by optimizing program organization and by further training of radiologists. Overall, the analysis showed a good sensitivity of the screening program in the Veneto Region, although the performance was inferior to that of excellence centers, and further action to improve it is possible. Assessment and review of interval cancers is an early indicator of screening efficacy which has not yet been fully adopted in Italian screening programs. Although using hospital discharge records to identify interval cancers may be affected by limited errors, such a procedure is particularly convenient, as data from hospital discharge records are available much in advance compared to cancer registries and are the most reliable source of information for areas uncovered by a cancer registry. Hospital discharge records-based procedures for interval cancers assessment should be employed routinely in screening programs.

Role of performance metrics in breast screening imaging - where are we and where should we be?

The NHS Breast Screening Programme (NHSBSP) was started in 1988 and is a large, organised cancer screening programme. It is delivered by 80 services across England and screens over 2 million women each year. As a screening programme, it must balance the detection of cancers against possible harm to women who do not have cancer. The NHSBSP was therefore designed with detailed information gathering and performance metrics right from the start. In this review paper, we examine how performance metrics in screening mammography have improved the national screening programme and the further developments and challenges that are expected in the years to come.

Improvement of Breast Cancer Patient Pathway Using EUSOMA Standards and European Guidelines

Queues in hospitals are directly affecting the quality of human life, which should have priority compared to other types of queues. The aim of this paper is to design a future value stream map of the system and patient pathway in terms of quality improvement in order to decrease the non-value added activities for breast cancer patients, doctors and nurses for a radiology unit in a Training and Research University Hospital based in Kocaeli, Turkey. Nowadays, the increased demand versus insufficient sources affect healthcare services due to poor quality with long queues during the diagnosis and treatment processes. For this paper, data were collected from personal observations, information technologies units and authorized employees. Moreover, data tracking and keeping systems are too poor for revealing the current situation. This paper provides an example of a current and future value stream map showing step by step where the bottlenecks are and how it can be improved and what specific benefits it will bring to the healthcare system. In consideration of all these outcomes, it is highly suggested that the hospital apply European Guidelines for quality assurance in breast cancer screening and diagnosis together with the mentioned above improvement suggestions using lean applications.

Effectiveness of and overdiagnosis from mammography screening in the Netherlands: population based study

Objective To analyse stage specific incidence of breast cancer in the Netherlands where women have been invited to biennial mammography screening since 1989 (ages 50-69) and 1997 (ages 70-75), and to assess changes in breast cancer mortality and quantified overdiagnosis.Design Population based study.Setting Mammography screening programme, the Netherlands.Participants Dutch women of all ages, 1989 to 2012.Main outcome measures Stage specific age adjusted incidence of breast cancer from 1989 to 2012. The extra numbers of in situ and stage 1 breast tumours associated with screening were estimated by comparing rates in women aged 50-74 with those in age groups not invited to screening. Overdiagnosis was estimated after subtraction of the lead time cancers. Breast cancer mortality reductions and overdiagnosis during 2010-12 were computed without (scenario 1) and with (scenario 2) a cohort effect on mortality secular trends.Results The incidence of stage 2-4 breast cancers in women aged 50 or more was 168 per 100 000 in 1989 and 166 per 100 000 in 2012. Screening would be associated with a 5% mortality reduction in scenario 1 and with no influence on mortality in scenario 2. In both scenarios, improved treatments would be associated with 28% reductions in mortality. Overdiagnosis has steadily increased over time with the extension of screening to women aged 70-75 and with the introduction of digital mammography. After deduction of clinical lead time cancers, 33% of cancers found in women invited to screening in 2010-12 and 59% of screen detected cancers would be overdiagnosed.Conclusions The Dutch mammography screening programme seems to have little impact on the burden of advanced breast cancers, which suggests a marginal effect on breast cancer mortality. About half of screen detected breast cancers would represent overdiagnosis.

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

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 < 0.005). Specificity of the fifth quintile was 98.4%.

CONCLUSION

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.