Comparison of Mean Glandular Dose between Full-Field Digital Mammography and Digital Breast Tomosynthesis

Early detection of breast cancer is diagnosed using mammography, the gold standard in breast screening. However, its increased use also provokes radiation-induced breast malignancy. Thus, monitoring and regulating the mean glandular dose (MGD) is essential. The purpose of this study was to determine MGD for full-field digital mammography (FFDM) and digital breast tomosynthesis (DBT) in the radiology department of a single centre. We also analysed the exposure factors as a function of breast thickness. A total of 436 patients underwent both FFDM and DBT. MGD was auto calculated by the mammographic machine for each projection. Patients’ data included compressed breast thickness (CBT), peak kilovoltage (kVp), milliampere-seconds (mAs) and MGD (mGy). Result analysis showed that there is a significant difference in MGD between the two systems, namely FFDM and DBT. However, the MGD values in our centre were comparable to other centres, as well as the European guideline (<2.5 mGy) for a standard breast. Although DBT improves the clinical outcome and quality of diagnosis, the risk of radiation-induced carcinogenesis should not be neglected. Regular quality control testing on mammography equipment must be performed for dose monitoring in women following a screening mammography in the future.

Intra- and inter-rater reliability of compressed breast thickness, applied force, and pressure distribution in screening mammography

Background Ensuring equivalent and reproducible breast compression between mammographic screening rounds is important for the diagnostic performance of mammography, yet the extent to which screening mammography positioning and compression is reproducible for the individual woman is unknown. Purpose To investigate the intra- and inter-rater reliability of breast compression in screening mammography. Materials and Methods Eleven breast-healthy women participated in the study. Two experienced radiographers independently positioned and compressed the breasts of each participant in two projections—right craniocaudal and left mediolateral oblique—and at two time points. The spatial pressure distribution on the compressed breast was measured using a pressure sensor matrix. Applied force, compressed breast thickness, force in field of view, contact area, mean pressure, and center of mass (anterio-posterior and mediolateral axes) were measured. The reliabilities of the measures between the time points for each radiographer (intra-rater reliability) and between the radiographers (inter-rater reliability) were analyzed using the intraclass correlation coefficient (ICC). Results Intra- and inter-rater reliabilities from both projections demonstrated good to excellent ICCs (≥0.82) for compressed breast thickness, contact area, and anterio-posterior center of mass. The other measures produced ICCs that varied from poor (≤0.42) to excellent (≥0.93) between time points and between radiographers. Conclusion Intra- and inter-rater reliability of breast compression was consistently high for compressed breast thickness, contact area, and anterio-posterior center of mass but low for mediolateral center of mass and applied force. Further research is needed to establish objective and clinically useful parameters for the standardization of breast compression.

Effect of Compression Force and Target or Target/Filter Combination on Mean Glandular Dose for Japanese Women in Full-Field Digital Mammography System

We constructed a mammography database of 807 Japanese women and 2,772 images obtained using five commercial full-field digital mammography (FFDM) devices at four different facilities. Five types of mammography devices fabricated by four manufacturers were used: one with a Mo target (AMULET F), one with Mo and Rh targets (Senographe DS), one with Mo and W targets (AMULET), and two with a W target (MAMMOMAT Fusion and Selenia Dimensions). The purpose of this study was to focus on the mean glandular dose (MGD) in the database and analyze the difference in the MGD of Japanese women radiographed by mammographic devices with different targets or target/filter combinations. Furthermore, we clarify the difference between the displayed and measured MGDs for the three types of mammography devices. The average compression pressure and compression breast thickness of the Japanese women in the mammography in this study were 90.9±21.7 N and 43.3±12.9 mm, respectively. The breast compression pressure slightly varied depending on the facility or FFDM device, while the compression breast thickness decreased with the increase in the compression pressure for all FFDM devices. Differences in breast compression thickness existed depending on the mammography devices. The MGDs of the two types of mammography devices using the W target were smallest (1.335±0.358, 1.218±0.464 mGy). The displayed and measured MGDs of the three types of FFDM devices had a good correlation. However, the difference between the displayed and measured MGDs of the two devices increased with the MGD.

Out With the Old and in With the New? Factors Involved in Migration of Older and Newer Generation Stereotactic Breast Biopsy Markers

Objective The purpose of this study was to investigate four commonly used stereotactic biopsy markers, two older and two newer generation, assessing percentage migration and factors influencing migration distance. Methods This was an IRB–approved retrospective review of upright stereotactic breast biopsies from May 2018 to May 2020 involving either older (Cork, Hourglass) or newer (Vision, X-shaped) generation markers. Markers were assessed for migration rate by two-sample Z-test and migration distance by analysis of variance. Univariate analysis was used to assess relationships between marker type and generation, patient characteristics, breast composition and thickness, procedure techniques, trainee involvement, and complications, correlating with migration distance. Multivariable analysis was performed for variables with P-value &lt; 0.1 on univariate analysis. Tukey’s test was used to compare all groups (P &lt; 0.05). Results A total of 732 stereotactic biopsies were performed with 508 using a Cork, Hourglass, Vision, or X-shaped marker. Overall migration rate was 181/508 (35.6%) with no difference between markers. Breast thickness and density were negatively associated with migration distance in univariate analysis. Older marker migration distance was greater than newer (2.6 cm vs 1.9 cm, respectively), which was significant after adjusting for breast thickness and density (P = 0.037). Density was a significant factor in migration distance, comparing fatty to nonfatty breasts (P &lt; 0.05) in univariate analysis. Conclusion No difference in migration rate was seen between the four biopsy markers. Vision and X-shaped markers demonstrate lower migration distance than Cork and Hourglass in multivariate analysis. There is an inverse relationship between breast density and marker migration distance.

Self-reported Pain Associated With Screening With Digital Breast Tomosynthesis

Objective We aimed to investigate self-reported pain during screening with digital breast tomosynthesis (DBT). Methods The study was approved by the Regional Committee for Medical and Health Research Ethics in the South East of Norway (2015/424). Women completed a questionnaire about experienced pain directly after the examination, August–November 2019. A numeric rating scale (NRS, 0–10) was used. Data on compression force (N), pressure (kPa), and compressed breast thickness (mm) were obtained from the Digital Imaging and Communication in Medicine header and density assessment software. Stepwise ordinary least-squares regression was used to estimate mean self-reported pain score with 95% confidence interval (CI) for values of compression force, pressure, and compressed breast thickness. Results The mean pain score was 1.9, whereof 19.3% (822/4266) of the women reported moderate or severe pain. The mean pain score of 2.6 (95% CI: 2.4–2.7) was observed at a compression force of 60 N, decreasing to 1.3 (95% CI: 1.2–1.4) at 130 N. The mean pain score of 1.3 (95% CI: 1.1–1.4) was at a compression pressure of 6 kPa, increasing to 2.9 (95% CI: 2.7–3.1) at 16 kPa. The mean pain score was 0.6 (95% CI: 0.4–0.6) at a compressed breast thickness of 20 mm, increasing to 2.9 (95% CI: 2.7–3.1) at 90 mm. Conclusion The mean pain score was low, 1.9 on NRS, for women screened with DBT. A compression force of 60–130 N and a pressure 6–16 kPa were associated with no or mild pain.

Distribution of pressure on the breast in mammography using flexible and rigid compression plates: implications on patient handling

Background Breast compression in mammography is important but is a source of discomfort and has been linked to screening non-attendance. Reducing compression has little effect on breast thickness, and likely little effect on image quality, due to force being absorbed in the stiff juxta thoracic area instead of in the central breast. Purpose To investigate whether a flexible compression plate can redistribute force to the central breast and whether this affects perceived pain. Material and Methods Twenty-eight women recalled from mammography screening were compressed with flexible and rigid plates while retaining force and positioning, 15 in the craniocaudal (CC) view and 13 in the mediolateral oblique (MLO) view. Pressure distribution was continuously measured using pressure sensors. Results The flexible plate showed greater mean breast pressure in both views: 2.8 versus 2.3 kPa for CC (confidence interval [CI] = 0.2–0.8) and 1.0 versus 0.5 kPa for MLO (CI = 0.2–0.6). The percentage of applied force distributed to the breast was significantly higher with the flexible plate, both on CC (36% vs. 22%, CI = 1–11) and MLO (30% vs. 14%, CI = 4–13). Conclusion The flexible plate redistributes pressure to the central breast, achieving a better compression, particularly in the MLO view, though much applied force is still applied to the juxta thoracic region.