Comparison of False-Positive Versus True-Positive Findings on Contrast-Enhanced Digital Mammography.

BACKGROUND. Contrast-enhanced digital mammography (CEDM) has been shown to outperform standard mammography while performing comparably to contrast-enhanced MRI. OBJECTIVE. The purpose of our study was to compare imaging characteristics of false-positive and true-positive findings on CEDM. METHODS. This retrospective study included women who underwent baseline screening CEDM between January 2013 and December 2018 assessed as BI-RADS category 0, 3, 4, or 5 and who underwent biopsy with histopathologic diagnosis or had a 2-year imaging follow-up. Lesion characteristics were extracted from CEDM reports. A true-positive finding was defined as a lesion in which biopsy yielded malignancy. A false-positive finding was defined as a lesion in which biopsy yielded benign or benign high-risk pathology or in which 2-year imaging follow-up was negative. RESULTS. Of 157 patients (median age, 52 years), 24 had a total of 26 true-positive lesions, and 133 had a total of 147 false-positive lesions. Of the 26 true-positive lesions, one (4%) exhibited only a mammographic finding on low-iodine images, 13 (50%) exhibited only a contrast finding on iodine images, and 12 (46%) exhibited both a mammographic finding on low-energy images and a contrast finding on iodine images. A true-positive result was more likely (p = .02) for lesions present on both low-energy images and iodine images (31%) than on low-energy images only (4%) or iodine images only (12%). Among lesions present on both low-energy and iodine images, a true-positive result was more likely (p < .001) when the type of mammographic finding was an asymmetry (46%) or calcification (80%) than a mass (11%) or distortion (0%). A true-positive result was more likely (p = .01) among those with, versus those without, an ultrasound correlate (36% vs 9%) and also was more likely (p = .02) among those with, versus those without, an MRI correlate (18% vs 2%). Of 25 false-positive calcifications, 24 had no associated mammographic enhancement; of five true-positive calcifications, four had mammographic enhancement. CONCLUSION. A low-energy mammographic finding with associated enhancement or a finding with a sonographic or MRI correlate predicts a true-positive result. Calcifications with associated enhancement had a high malignancy rate. Nonetheless, half of true-positive lesions enhanced on iodine images without a mammographic finding on low-energy images. CLINICAL IMPACT. These observations inform radiologists' management of abnormalities detected on screening CEDM.

Architecture distortion score (ADS) in malignancy risk stratification of architecture distortion on contrast-enhanced digital mammography.

OBJECTIVE: To develop a risk predictor model in evaluation of tomosynthesis-detected architectural distortion (AD) based on characteristics of contrast-enhanced digital mammography (CEDM). METHODS: Ninety-four AD lesions on CEDM in combination with tomosynthesis were retrospectively reviewed from 92 consecutive women (mean age, 52.4 years ± 7.9) with abnormal diagnostic or screening mammography. CEDM results were correlated with histology of ADs using cross-tabulation for statistical analysis. Predictors for risk of malignancy from CEDM characteristics (background parenchyma enhancement, degree of AD enhancement, enhancing morphology, size of enhancement, and enhancing spiculations) and patient's age were evaluated using logistic regression. We propose a sum score, termed AD score (ADS), for risk stratification and corresponding suggested BI-RADS category. RESULTS: Thirty-three of ninety-four (35.1%) of detected AD lesions were malignant. The sensitivity, specificity, PPV, and NPV of CEDM in evaluation of malignant AD are 100%, 42.6%, 48.5%, and 100%, respectively. Absence of AD enhancement on CEDM is highly indicative of no underlying malignancy. On multivariate analysis, the predictors on CEDM with statistical significance are (1) marked intensity of AD enhancement (OR, 22.6; 95%CI 3.1, 166.6; p = .002); and (2) presence of enhancing spiculations (OR, 9.1; 95%CI 2.2, 36.5; p = .002). A prediction model whose scores (ADS) given by ranking of OR of all predictors with AUC of 0.934 and Brier score of 0.0956 was developed. CONCLUSION: ADS-based lesion characterization on CEDM enables risk assessment of tomosynthesis-detected AD lesions. KEY POINTS: • Architecture distortions presenting with marked enhancement intensity and presence of enhancing spiculations are highly associated with risk of malignancy. • Absence of architecture distortion enhancement in minimal or mild background parenchyma enhancement on CEDM indicates low risk of breast malignancy (NPV = 100%).

Contrast-Enhanced Digital Mammography Screening for Intermediate-Risk Women With a History of Lobular Neoplasia.

OBJECTIVE. The objective of this study was to assess to the role of contrast-enhanced digital mammography (CEDM) as a screening tool in women at intermediate risk for developing breast cancer due to a personal history of lobular neoplasia without additional risk factors. MATERIALS AND METHODS. In this institutional review board-approved, observational, retrospective study, we reviewed our radiology department database to identify patients with a personal history of breast biopsy yielding lobular neoplasia who underwent screening CEDM at our institution between December 2012 and February 2019. A total of 132 women who underwent 306 CEDM examinations were included. All CEDM examinations were interpreted by dedicated breast imaging radiologists in conjunction with a review of the patient's clinical history and available prior breast imaging. In statistical analysis, sensitivity, specificity, NPV, positive likelihood ratio, and accuracy of CEDM in detecting cancer were determined, with pathology or 12-month imaging follow-up serving as the reference standard. RESULTS. CEDM detected cancer in six patients and showed an overall sensitivity of 100%, specificity of 88% (95% CI, 84-92%), NPV of 100%, and accuracy of 88% (95% CI, 84-92%). The positive likelihood ratio of 8.33 suggested that CEDM findings are 8.3 times more likely to be positive in an individual with breast cancer when compared with an individual without the disease. CONCLUSION. CEDM shows promise as a breast cancer screening examination in patients with a personal history of lobular neoplasia. Continued investigation with a larger patient population is needed to determine the true sensitivity and positive predictive value of CEDM for these patients.

Multireader comparison of contrast-enhanced mammography versus the combination of digital mammography and digital breast tomosynthesis in the preoperative assessment of breast cancer.

PURPOSE: To compare preoperative contrast-enhanced spectral mammography (CEM) versus digital mammography plus digital breast tomosynthesis (DM + DBT) in detecting breast cancer (BC) and assessing its size. MATERIAL AND METHODS: We retrospectively included 78 patients with histological diagnosis of BC who underwent preoperative DM, DBT, and CEM over one year. Four readers, blinded to pathology and clinical information, independently evaluated DM + DBT versus CEM to detect BC and measure its size. Readers' experience ranged 3-10 years. We calculated the per-lesion cancer detection rate (CDR) and the complement of positive predictive value (1-PPV) of both methods, stratifying analysis on the total of lesions, index lesions, and additional lesions. The agreement in assessing cancer size versus pathology was assessed with Bland-Altman analysis. RESULTS: 100 invasive BCs (78 index lesions and 22 additional lesions) were analyzed. Compared to DM + DBT, CEM showed higher overall CDR in less experienced readers (range 0.85-0.90 vs. 0.95-0.96), and higher CDR for additional lesions, regardless of the reader (range 0.54-0.68 vs. 0.77-0.86). CEM increased the detection of additional disease in dense breasts in all readers and non-dense breasts in less experienced readers only. The 1-PPV of CEM (range 0.10-0.18) was comparable to that of DM + DBT (range 0.09-0.19). At Bland-Altman analysis, DM + DBT and CEM showed comparable mean differences and limits of agreement in respect of pathologic cancer size. CONCLUSION: Preoperative CEM improved the detection of additional cancer lesions compared to DM + DBT, particularly in dense breasts. CEM and DM + DBT achieved comparable performance in cancer size assessment.

Contrast-Enhanced Digital Mammography: Technique, Clinical Applications, and Pitfalls.

OBJECTIVE. Contrast-enhanced digital mammography (CEDM) combines the high spatial resolution of mammography with the improved enhancement provided by contrast medium. In this article, CEDM technique-the current and potential clinical applications and current challenges-will be reviewed. CONCLUSION. CEDM is a promising technique in the supplemental evaluation of patients with mammographically inconclusive findings and potentially in the screening of women with mammographically dense breasts. CEDM is emerging as a cost-effective alternative to dynamic contrast-enhanced MRI to stage newly diagnosed breast cancer and evaluate response to neoadjuvant chemotherapy.

Evaluation of contrast-enhanced digital mammography (CEDM) in the preoperative staging of breast cancer: Large-scale single-center experience.

One of the most important indications for contrast-enhanced breast imaging is the presurgical breast cancer (BC) staging. This is a large-scale single-center experience which evaluates the role of CEDM in presurgical staging and its impact on surgical planning. The aims of this retrospective study were to define the diagnostic performance of CEDM in the presurgical setting and to identify which types of patients could benefit from having CEDM. We selected 326 patients with BC who underwent CEDM as preoperative staging and had breast cancer-related surgery at our institution. We analyzed those cases in which CEDM led to additional imaging or biopsy and those in which it changed the type of surgery that was planned according to conventional breast imaging (CI) techniques (digital mammography, tomosynthesis and bilateral handheld ultrasound). CEDM sensitivity in identifying the index lesion and sensitivity, specificity, positive (PPV) and negative (NPV) predictive values, and accuracy in the correct preoperative staging of BC of the whole population and in various subgroups were calculated. CEDM sensitivity for the index lesion was 98.8% (322/326), which led to additional breast imaging in 23.6% (77/326) of patients and additional biopsies in 17.5% (57/326). CEDM changed the type of surgery in 18.4% (60/326). In the preoperative breast cancer staging, CEDM sensitivity, specificity, PPV, NPV, and accuracy produced results of 93%, 98%, 90%, 98%, and 97%, respectively. CEDM performance was better in patients with palpable lesions. CEDM has an excellent diagnostic performance in the presurgical staging of BC. Symptomatic patients with palpable lesions benefitted most from preoperative CEDM, with a statistically significant difference compared with nonpalpable.

Contrast-Enhanced Mammography: A Systematic Guide to Interpretation and Reporting.

OBJECTIVE: The purpose of this article is to discuss the essential steps involved in performing, interpreting, managing, and reporting findings on contrast-enhanced mammography for successful implementation into clinical practice. CONCLUSION: To successfully implement contrast-enhanced mammography into clinical practice, an understanding about the acquisition of images, image interpretation, and reporting of the spectrum of negative, benign, and malignant findings is essential.

Preoperative loco-regional staging of invasive lobular carcinoma with contrast-enhanced digital mammography (CEDM).

The aim of our study was to assess the performance of contrast-enhanced digital mammography (CEDM) in the preoperative loco-regional staging of invasive lobular carcinoma (ILC) patients, about the valuation of the extension of disease and in measurement of lesions. Then, we selected retrospectively, among the 1500 patients underwent to CEDM at the Breast Diagnostics Department of the Careggi University Hospital of Florence and the National Cancer Institute of Milan from September 2016 to November 2018, 31 women (mean age 57.1 aa; range 41-78 aa) with a definitive histological diagnosis of ILC. CEDM has proved to be a promising imaging technique, being characterized by a sensitivity of 100% in the detection of the index lesion, and of 84.2% in identifying any adjunctive lesions: It was the presence of a non-mass enhancement (NME) to lower the sensitivity of the technique (25% vs. 100% for mass-like enhancements or a mass closely associated with a NME). Specificity in the characterization of additional lesions was 66.7%, and the diagnosis of the extension of disease was correct in 77.4% of cases: NME also led to a decrease in diagnostic accuracy in the evaluation of disease extension up to 40% versus 85% for masses and 80% for masses associated with NME (M/NME). Moreover, in 12/31 (38.7%), CEDM allowed to correctly identify lesions not shown by mammography + ultrasonography + tomosynthesis: In the half of these (6/12), there was a multicentricity, thus allowing an adequate surgical planning change. CEDM was also very accurate in analyzing the maximum diameter of the masses, while it was much less reliable in the case of the M/NME and pure NME. In conclusion, CEDM is a new promising imaging technique in the loco-regional preoperative staging and in the evaluation of disease extension for ILC, especially in case of mass enhancement lesions.

The Future of Contrast-Enhanced Mammography.

OBJECTIVE: The purpose of this article is to discuss facilitators of and barriers to future implementation of contrast-enhanced mammography (CEM) in the United States. CONCLUSION: CEM provides low-energy 2D mammographic images analogous to digital mammography and contrast-enhanced recombined images that allow assessment of neovascularity similar to that offered by MRI. The utilization of CEM in the United States is currently low but could increase rapidly given the many potential indications for its clinical use.

Comparative Dose of Contrast-Enhanced Spectral Mammography (CESM), Digital Mammography, and Digital Breast Tomosynthesis.

OBJECTIVE: The purpose of this study is to provide a more accurate estimation of the radiation dose of contrast-enhanced spectral mammography (CESM) relative to that of 2D digital mammography and tomosynthesis using phantom and patient data and an accepted dosimetry protocol that eliminates vendor-specific average glandular dose (AGD) estimates while including breast density. MATERIALS AND METHODS: Patient and phantom AGD estimation was performed using two vendors (system 1 and system 2) in five imaging modes, including 2D, 3D, and CESM imaging. Patient AGD was retrospectively estimated from 45 patients who underwent mammography with all imaging modes during 2012-2016. Patient and phantom AGD were estimated using accepted European and International Atomic Energy Agency protocols for dosimetry and were compared across imaging modes using a paired t test with Bonferroni correction. RESULTS: Phantom data showed that the imaging modes with the lowest to highest AGDs were system 1 2D, followed by system 2 2D and system 2 3D, which had comparable values (p = 0.6), followed by system 1 CESM, and then by system 2 2D plus 3D. One hundred eighty views in 45 patients showed that the system 1 CESM AGD was 1.8 times greater than the system 1 2D AGD (p < 0.001), 1.2 times greater than the system 2 2D AGD (p < 0.001), 1.2 times greater than the system 2 3D AGD (p < 0.001), and 0.6 times less than the system 2 2D plus 3D AGD (p < 0.001). CONCLUSION: The CESM dose for system 1 is within an acceptable range as compared with other commonly performed mammographic examinations and should not preclude its use as a diagnostic breast imaging tool.

Susceptibility of iodine concentration map of dual-energy contrast-enhanced digital mammography for quantitative and tumor enhancement assessment.

Background Dual-energy (DE) contrast-enhanced digital mammography (DE-CEDM) provides additional information on tumor angiogenesis. Purpose To investigate the susceptibility of reconstructing color-coded iodine concentration maps on the basis of quantitative calibrations of the iodine concentration and contrast-to-noise ratio (CNR) in DE-CEDM applications. Material and Methods A custom-made phantom filled with iodine concentrations in the range of 0.1-10 mg/cm2 was used in calibrations. All DE images were acquired using the GE Senographe Essential system. From DE subtraction images, the image contrast and CNR were obtained, and the quantitative relationship between these two metrics and the iodine concentration at each phantom thickness was investigated. The quantitative CNR calibration curves were applied to reconstruct color-coded iodine maps on a pixel-by-pixel basis. Results Both the mean contrast and mean CNR increased linearly with the iodine concentration. The iodine concentration estimated from the iodine map reconstructed from quantitative CNR calibrations was highly consistent with the desired iodine concentration (R2 = 0.989), and smaller relative errors (in the range of 3.0-19.5%) were observed with iodine concentrations not less than 1 mg/cm2. Conclusion An iodine concentration map could be reconstructed based on the linear relationship between the CNR and iodine concentration. From the color-coded iodine concentration map, the contrast medium enhancement phenomenon could be further estimated quantitatively, and tumor enhancement patterns could be easily observed.

Potential Cost Savings of Contrast-Enhanced Digital Mammography.

OBJECTIVE: The purpose of this article is to discuss whether the sensitivity and specificity of contrast-enhanced digital mammography (CEDM) render it a viable diagnostic alternative to breast MRI. CONCLUSION: That CEDM couples low-energy images (comparable to the diagnostic quality of standard mammography) and subtracted contrast-enhanced mammograms make it a cost-effective modality and a realistic substitute for the more costly breast MRI.

Contrast-enhanced dual energy mammography with a novel anode/filter combination and artifact reduction: a feasibility study.

OBJECTIVES: To demonstrate the feasibility of contrast-enhanced dual-energy mammography (CEDEM) using titanium (Ti) filtering at 49 kVp for high-energy images and a novel artefact reducing image-subtraction post-processing algorithm. METHODS: Fifteen patients with suspicious findings (ACR BI-RADS 4 and 5) detected with digital mammography (MG) that required biopsy were included. CEDEM examinations were performed on a modified prototype machine. Acquired HE and low-energy raw data images were registered non-rigidly to compensate for possible subtle tissue motion. Subtracted CEDEM images were generated via weighted subtraction, using a fully automatic, locally adjusted tissue thickness-dependent subtraction factor to avoid over-subtraction at the breast border. Two observers evaluated the MG and CEDEM images according to ACR BI-RADS in two reading sessions. Results were correlated with histopathology. RESULTS: Seven patients with benign and eight with malignant findings were included. All malignant lesions showed a strong contrast enhancement. BI-RADS assessment was altered in 66.6 % through the addition of CEDEM, resulting in increased overall accuracy. With CEDEM, additional lesions were depicted and false-positive rate was reduced compared to MG. CONCLUSIONS: CEDEM using Ti filtering with 49 kVp for HE exposures is feasible in a clinical setting. The proposed image-processing algorithm has the potential to reduce artefacts and improve CEDEM images. KEY POINTS: • CEDEM with a titanium filter is feasible in a clinical setting. • Breast thickness-dependent image subtraction has the potential to improve CEDEM images. • The proposed image-processing algorithm reduces artefacts.

The Utility of Contrast-Enhanced Mammography in the Evaluation of Bloody Nipple Discharge-A Multicenter Study in the Asian Population.

OBJECTIVE: To assess the efficacy of contrast-enhanced mammography (CEM) in differentiating benign from malignant breast lesions in Asian patients with bloody nipple discharge (BND). METHODS: This retrospective study included 58 women with BND (mean age: 51.7 years) who underwent standardized CEM at institutions in Taiwan and Singapore. Lesion characteristics (size, enhancement, conspicuity, shape, margins) were evaluated on CEM by blinded radiologists. Non-enhanced mammography (MMG) and ultrasound (US) within a defined timeframe were compared for diagnostic accuracy. Benign or malignant status was confirmed by biopsy or 2-year imaging follow-up. RESULTS: Malignancy was found in 29 of 58 lesions (50.0%), with ductal carcinoma in situ (DCIS) being the most common. CEM demonstrated a 100% negative predictive value (NPV) for non-enhancing lesions. Significant predictors of malignancy on multivariate analysis include enhancing lesions of size ≥ 1.5 cm (p-value 0.025) and suspicious morphological features (irregular/spiculated margins, irregular shape, segmental/linear NME distribution) (p-value < 0.001). CEM outperformed MMG (sensitivity: 58.6%) and US (sensitivity: 79.3%), achieving a sensitivity of 100% and the highest diagnostic accuracy at 81.3%. Additionally, a CEM size cut-off of 1.5 cm yielded a sensitivity of 73.5% and a specificity of 84.3%. CONCLUSIONS: CEM effectively differentiates benign from malignant lesions in patients with BND, improving diagnostic accuracy and potentially reducing unnecessary interventions.

Diagnostic Accuracy and Incremental Value of Contrast-Enhanced Mammography Compared With Full Field Digital Mammography in a Tertiary Cancer Care Center.

OBJECTIVE: To assess the diagnostic accuracy and incremental value of contrast-enhanced mammography (CEM) compared with full-field digital mammography (FFDM). METHODOLOGY: A retrospective analysis was performed with 150 consecutive patients who underwent CEM at our institute between November 2020 and February 2021, fulfilling the inclusion criteria. The first round of analysis included a review of FFDM with an interpretation of findings as per the Breast Imaging Reporting and Data System (BIRADS) lexicon and the assignment of the BIRADS category to the detected abnormalities. After this documentation, a second round of analysis included a review of recombined subtracted images of CEM. The diagnostic accuracy of FFDM and CEM was calculated with histopathology as the gold standard. RESULTS: Among the 150 cases assessed, 202 lesions were detected with histopathological correlation, of which 42 were benign and 160 were malignant. The sensitivity of FFDM was 90.6% compared to 98.12% for CEM. The specificity of FFDM was 66.7% compared to 76.19% for CEM. The negative predictive value (NPV) of FFDM was low, at 65.12%; CEM showed a better NPV, at 91.43%. The positive predictive value (PPV) was almost the same, at 94.01% for CEM and 91.19% for FFDM. The area under the curve (AUC) was superior for CEM compared to that of FFDM, with a value of 0.87. FFDM had a low sensitivity, especially in dense breast parenchyma, at 88.79% and a specificity of 70%, whereas CEM showed a higher sensitivity, specificity, and NPV, measuring 99.14%, 76.67%, and 95.83%, respectively. CONCLUSION: Superior sensitivity and high NPV for CEM make it a preferable modality compared with FFDM, especially in dense breast parenchyma, where CEM overcomes the limitations of FFDM. We conclude that CEM is superior to FFDM in evaluating the extent of disease, additional satellite lesion detection, and ruling out ambiguous findings.

State-of-the-art for contrast-enhanced mammography.

Contrast-enhanced mammography (CEM) is an emerging breast imaging technology with promise for breast cancer screening, diagnosis, and procedural guidance. However, best uses of CEM in comparison with other breast imaging modalities such as tomosynthesis, ultrasound, and MRI remain inconclusive in many clinical settings. This review article summarizes recent peer-reviewed literature, emphasizing retrospective reviews, prospective clinical trials, and meta-analyses published from 2020 to 2023. The intent of this article is to supplement prior comprehensive reviews and summarize the current state-of-the-art of CEM.

Brief communication: The current status of contrast-enhanced mammography in breast imaging.

Improvising and developing state of the art techniques for breast cancer detection have always been an area of great interest in the field of imaging. Adding intravenous contrast to any imaging study, is well-known to increase the sensitivity and specificity of detection of a pathological process, especially in the setting of neoplasia secondary to tumor neoangiogenesis. Contrast enhanced MRI is known to be highly sensitive breast cancer screening tool till date, however, has been limited by long scan times, claustrophobia experienced by some women and high false positive findings. Despite continued advances in digital mammography technique, significant limitations have always been experienced in detection of small cancers especially in the setting of dense breast parenchyma. Implementing dual energy subtraction technique to digital mammography, made contrast enhanced mammography a viable technique to improve cancer detection. We aim to discuss the status of contrast enhanced mammography in this brief communication, emphasizing technical background, image acquisition, clinical applications, and future directions.

Multiscale Monte Carlo simulations for dosimetry in x-ray breast imaging: Part I - Macroscopic scales.

BACKGROUND: X-ray breast imaging modalities are commonly employed for breast cancer detection, from screening programs to diagnosis. Thus, dosimetry studies are important for quality control and risk estimation since ionizing radiation is used. PURPOSE: To perform multiscale dosimetry assessments for different breast imaging modalities and for a variety of breast sizes and compositions. The first part of our study is focused on macroscopic scales (down to millimeters). METHODS: Nine anthropomorphic breast phantoms with a voxel resolution of 0.5 mm were computationally generated using the BreastPhantom software, representing three breast sizes with three distinct values of volume glandular fraction (VGF) for each size. Four breast imaging modalities were studied: digital mammography (DM), contrast-enhanced digital mammography (CEDM), digital breast tomosynthesis (DBT) and dedicated breast computed tomography (BCT). Additionally, the impact of tissue elemental compositions from two databases were compared. Monte Carlo (MC) simulations were performed with the MC-GPU code to obtain the 3D glandular dose distribution (GDD) for each case considered with the mean glandular dose (MGD) fixed at 4 mGy (to facilitate comparisons). RESULTS: The GDD within the breast is more uniform for CEDM and BCT compared to DM and DBT. For large breasts and high VGF, the ratio between the minimum/maximum glandular dose to MGD is 0.12/4.02 for DM and 0.46/1.77 for BCT; the corresponding results for a small breast and low VGF are 0.35/1.98 (DM) and 0.63/1.42 (BCT). The elemental compositions of skin, adipose and glandular tissue have a considerable impact on the MGD, with variations up to 30% compared to the baseline. The inclusion of tissues other than glandular and adipose within the breast has a minor impact on MGD, with differences below 2%. Variations in the final compressed breast thickness alter the shape of the GDD, with a higher compression resulting in a more uniform GDD. CONCLUSIONS: For a constant MGD, the GDD varies with imaging modality and breast compression. Elemental tissue compositions are an important factor for obtaining MGD values, being a source of systematic uncertainties in MC simulations and, consequently, in breast dosimetry.

Investigation of test methods for QC in dual-energy based contrast-enhanced digital mammography systems: II. Artefacts/uniformity, exposure time and phantom-based dosimetry.

Part II of this study describes constancy tests for artefacts and image uniformity, exposure time, and phantom-based dosimetry; these are applied to four mammography systems equipped with contrast enhanced mammography (CEM) capability. Artefacts were tested using a breast phantom that simulated breast shape and thickness change at the breast edge. Image uniformity was assessed using rectangular poly(methyl)methacrylate PMMA plates at phantom thicknesses of 20, 40 and 60 mm, for the low energy (LE), high energy (HE) images and the recombined CEM image. Uniformity of signal and of the signal to noise ratio was quantified. To estimate CEM exposure times, breast simulating blocks were imaged in automatic exposure mode. The resulting x-ray technique factors were then set manually and exposure time for LE and HE images and total CEM acquisition time was measured with a multimeter. Mean glandular dose (MGD) was assessed as a function of simulated breast thickness using three different phantom compositions: (i) glandular and adipose breast tissue simulating blocks combined to give glandularity values that were typical of those in a screening population, as thickness was changed (ii) PMMA sheets combined with polyethylene blocks (iii) PMMA sheets with spacers. Image uniformity was superior for LE compared to HE images. Two systems did not generate recombined images for the uniformity test when the detector was fully covered. Acquisition time for a CEM image pair for a 60 mm thick breast equivalent phantom ranged from 3.4 to 10.3 s. Phantom composition did not have a strong influence on MGD, with differences generally smaller than 10%. MGD for the HE images was lower than for the LE images, by a factor of between 1.3 and 4.0, depending on system and simulated breast thickness. When combined with the iodine signal assessment in part I, these tests provide a comprehensive assessment of CEM system imaging performance.

Examining the effectiveness of supplementary imaging modalities for breast cancer screening in women with dense breasts: A systematic review and meta-analysis.

PURPOSE: To systematically review studies on the effectiveness of supplementary imaging for breast cancer screening in women with dense breasts. MATERIALS AND METHODS: A systematic search of peer-reviewed publications in English (January 2000 to March 2021) was carried out. Eight databases were used to retrieve the studies: MEDLINE, CINAHL, Cochrane Central Register of Controlled Trials, Cochrane Clinical Answers, Cochrane Database of Systematic Reviews, Cochrane Methodology Register, PubMed, and Web of Science. Two radiographers and an academic independently reviewed the articles to determine if the studies met inclusion criteria. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Summary estimates of diagnostic accuracy were obtained by using proportion and diagnostic metanalysis. RESULTS: From 3764 studies that underwent title and abstract screening, 221 studies underwent full-text screening. Of these 42 were included in the qualitative and quantitative synthesis. Results for sensitivity, specificity, positive and negative predictive values, cancer detection rates, recall and biopsy rates in women with dense breasts undergoing supplementary imaging were reported. Studies included in this review were heterogeneous, as was the proportion of women undergoing prevalence and incidence screening rounds. CONCLUSIONS: Supplementary screening among women with dense breasts who had recent negative mammograms can consistently identify additional cancers and lead to further recalls and biopsies.