Performance Of Digital Breast Tomosynthesis Research Articles

Quantitative assessment of microcalcification cluster image quality in digital breast tomosynthesis, 2-dimensional and synthetic mammography.

Quantitative assessment of microcalcification (MC) cluster image quality is presented, in terms of cluster signal-difference-to-noise ratio (SDNR) intercomparison among digital breast tomosynthesis (DBT) and 2-dimensional (2D) and synthetic-2-dimensional (s2D) mammography. A phantom that provides realistic appearance of MC clusters located in uniform and nonuniform background was imaged in 2D and DBT, considering various scattering conditions. MC cluster SDNR differentiation is investigated with respect to MC particle size (uniform background) and surrounding parenchyma density (nonuniform background). An accurate MC cluster segmentation method was used to delineate individual MC particles and estimate MC cluster SDNR. Analysis of the uniform part of the phantom indicated higher performance of DBT and 2D over s2D for the smallest cluster size (106-177 μm), no difference among mammographic modes for the largest MC cluster (224-354 μm), and enhanced role of 2D for decreasing cluster size and increasing scattering. Analysis of the nonuniform part of the phantom indicated DBT performed better than 2D and s2D in case of dense parenchyma pattern, while 2D and s2D did not differ across parenchyma density patterns and scattering conditions. The presented MC cluster SDNR analysis was capable of revealing subtle differences among mammographic modes and suggests a methodology for clinical image quality assessment. Graphical abstract.

Diagnostic Performance of Digital Breast Tomosynthesis for Breast Suspicious Calcifications From Various Populations: A Comparison With Full-field Digital Mammography

The diagnostic performance difference between digital breast tomosynthesis (DBT) and conventional full-field digital mammography (FFDM) for breast suspicious calcifications from various populations is unclear. The objective of this study is to determine whether DBT exhibits the diagnostic advantage for breast suspicious calcifications from various populations compared with FFDM. Three hundred and five patients were enrolled (of which seven patients with bilateral lesions) and 312 breasts images were retrospectively analyzed by three radiologists independently. The postoperative pathology of breast calcifications was the gold standard. Breast cancer was diagnosed utilizing DBT and FFDM with sensitivities of 92.9% and 88.8%, specificities of 87.9% and 75.2%, positive predictive values of 77.8% and 62.1%, negative predictive values of 96.4% and 93.6%, respectively. DBT exhibited significantly higher diagnostic accuracy for benign calcifications compared with FFDM (87.9% vs 75.2%), and no advantage in the diagnosis of malignant calcifications. DBT diagnostic accuracy was notably higher than FFDM in premenopausal (88.4% vs 78.8%), postmenopausal (90.2% vs 77.2%), and dense breast cases (89.4% vs 81.9%). There was no significant difference in non-dense breast cases. In our study, DBT exhibited a superior advantage in dense breasts and benign calcifications cases compared to FFDM, while no advantage was observed in non-dense breasts or malignant calcifications cases. Thus, in the breast cancer screening for young women with dense breasts, DBT may be recommended for accurate diagnosis. Our findings may assist the clinicians in applying the optimal techniques for different patients and provide a theoretical basis for the update of breast cancer screening guideline.

The role of breast tomosynthesis in a predominantly dense breast population at a tertiary breast centre: breast density assessment and diagnostic performance in comparison with MRI

ObjectivesTo compare breast density measured on digital breast tomosynthesis (DBT) (BI-RADS-based breast composition and fully-automatic estimation) and magnetic resonance imaging (MRI) (BI-RADS amount of fibroglandular tissue), and to evaluate the diagnostic performance in terms of sensitivity and specificity of DBT and MRI in a predominantly dense breast population.MethodsBetween 2015 and 2016, 152 women with 103 breast malignancies, who underwent 3-T breast MRI and DBT within 2 months’ time, were enrolled in this study. Breast composition/fibroglandular tissue and findings on DBT (two readers) and MRI were reported using BI-RADS 5th edition. Digital mammography images were analysed for breast percent density (PD) using the Libra software tool.ResultsA majority of women had dense breasts as categorised by breast composition c (heterogeneously dense) (68%) and d (extremely dense) (15%). The mean PD was 44% (range, 18-89%) and the correlation between breast composition and PD was r = 0.6. The diagnostic performance of MRI was significantly higher compared to DBT for one reader as described by the area under the receiver operating characteristic (ROC) curve (p = 0.004) and of borderline significance for the other reader (p = 0.052).ConclusionsMRI had higher diagnostic performance than DBT in a dense breast population in the tertiary setting.Key Points• MRI had higher diagnostic performance than DBT in a dense breast population• Diagnostic performance of DBT was comparable to MRI in women with fatty breasts• MRI was superior to DBT in preoperative breast cancer size assessment

Synthesized Mammography: The New Standard of Care When Screening for Breast Cancer with Digital Breast Tomosynthesis?

This study aims to evaluate the screening performance of digital breast tomosynthesis (DBT) combined with synthesized mammography (SM) vs combined with full-field digital mammography (FFDM). We retrospectively reviewed all screening studies utilizing FFDM + DBT (n = 7845) and SM + DBT (n = 14,776) between April 1, 2013, and February 15, 2016. Recall rate, biopsy rate, positive predictive value 1 (PPV1), positive predictive value 3 (PPV3), and cancer detection rate (CDR) were compared between the two groups. A generalized linear mixed model specifying the reading radiologist as the random effect and controlling for age was used to compare clinical outcomes between the two groups. The overall recall rate was significantly lower in the SM + DBT cohort compared to the FFDM + DBT cohort (7.06% vs 7.63%, P = .04). There was no difference in biopsy rate, PPV1, PPV3, or CDR between the two groups. When DBT is performed for screening, the use of SM rather than acquiring an additional FFDM has no significant effect on biopsy rate, PPV1, PPV3, or CDR. We found a decrease in recall rate in the SM + DBT group, which may be related to the learning curve of interpreting DBT. These findings support the use of SM for patients undergoing screening with DBT.

Diagnostic performance of digital breast tomosynthesis and full-field digital mammography with new reconstruction and new processing for dose reduction.

The main barrier to adoption of digital breast tomosynthesis (DBT) plus full-field digital mammography (FFDM) is radiation exposure dose. The purpose of this study was to evaluate the diagnostic performance of DBT plus FFDM, both with newly developed technology (nd), at a dose comparable to that of the conventional FFDM alone. Nine hundred and thirteen participants were recruited from May 2014 to January 2016 consecutively. For each subject, the exposure setting for DBT(nd)+FFDM(nd) was also used for the conventional FFDM alone. Retrospective reader studies were performed: DBT(nd)+FFDM(nd) (142 cases, including 42 cancer cases) and conventional FFDM (258 cases, including 87 cancer cases). Eight radiologists provided Japanese categorizations and probability of malignancy independently. Diagnostic performance was assessed by comparing sensitivity, specificity, and area under the receiver operating characteristic curve (AUC). Two-sided P values were calculated. DBT(nd)+FFDM(nd) showed sensitivity and AUC significantly increased over the conventional FFDM (85.4 vs. 80.3%, P=0.015 and 90.9 vs. 88.3%, P=0.049) and specificity did not significantly increase (89.6 vs. 88.4%, P=0.52). The mean glandular dose (MGD) difference of DBT(nd)+FFDM(nd) and conventional FFDM was not significant (difference -0.11mGy, P=0.08). In this study population, DBT plus FFDM, both with newly developed technology, provided diagnostic performance improved over the conventional FFDM alone, even at comparable MGD.

Digital breast tomosynthesis plus mammography, magnetic resonance imaging plus mammography and mammography alone: A comparison of diagnostic performance in symptomatic women.

To compare the diagnostic efficiency of digital breast tomosynthesis (DBT) plus digital mammography (DM) and magnetic resonance imaging (MRI) plus DM in symptomatic women. The protocol used in our study was accepted by the ethics committee at our hospital, and informed consent was obtained from all patients. Between June and December 2014, 197 patients with 238 histologically proven lesions all underwent DM, DBT and MRI. Two radiologists were responsible for interpreting all images according to the Breast Imaging Reporting and Data System (BI-RADS). The diagnostic performance of each method was assessed by receiver-operating characteristic (ROC) curve. The sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were compared using McNemar's test and Fisher's exact test. A Kappa test was used to assess the interobserver agreement. The area under the ROC curve (AUC) was lower in the group that underwent DM alone (Radiologist1 [R1], 0.849; Radiologist2 [R2], 0.850) than in the group that underwent DBT plus DM (R1, 0.907, P = 0.0204; R2, 0.900, P = 0.0239) and MRI plus DM (R1, 0.939, P = 0.0006; R2, 0.935, P = 0.0009). However, the difference between the group that received DBT plus DM and the group that received MRI plus DM was not significant (R1, P = 0.1262; R2, P = 0.0843). The accuracy (R1, 71.8%; R2, 71.4%) and sensitivity (R1, 71.9%; R2, 71.2%) of DM were lower than those of DBT ((accuracy: R1, 85.3%, P = 0.001; R2, 83.6%, P < 0.001; sensitivity: R1,92.1%, P < 0.001; R2, 90.8%, P < 0.001) and MRI combined with DM (accuracy: R1, 90.3%, P = 0.001; R2, 90.7%, P < 0.001; sensitivity: R1, 94.7%, P < 0.001; R2, 95.4%, P < 0.001). In contrast, no significant difference was observed between DBT and MRI combined with DM (accuracy: R1, P = 0.644; R2, P = 0.360; sensitivity: R1, P = 0.502; R2, P = 0.359). The interobserver agreement of each method was excellent (k = 0.894 0.919 and 0.882 for DM, DBT and MRI combined with DM, respectively). The diagnostic performance of DBT and MRI combined with DM is superior to that of DM alone in symptomatic women; MRI plus DM is slightly better than that of DBT plus DM, but this difference was not statistically significant.

Design and application of a structured phantom for detection performance comparison between breast tomosynthesis and digital mammography

This paper introduces and applies a structured phantom with inserted target objects for the comparison of detection performance of digital breast tomosynthesis (DBT) against 2D full field digital mammography (FFDM). The phantom consists of a 48 mm thick breast-shaped polymethyl methacrylate (PMMA) container filled with water and PMMA spheres of different diameters. Three-dimensionally (3D) printed spiculated masses (diameter range: 3.8–9.7 mm) and non-spiculated masses (1.6–6.2 mm) along with microcalcifications (90–250 µm) were inserted as targets.Reproducibility of the phantom application was studied on a single system using 30 acquisitions. Next, the phantom was evaluated on five different combined FFDM & DBT systems and target detection was compared for FFDM and DBT modes. Ten phantom images in both FFDM and DBT modes were acquired on these 5 systems using automatic exposure control. Five readers evaluated target detectability. Images were read with the four-alternative forced-choice (4-AFC) paradigm, with always one segment including a target and 3 normal background segments. The percentage of correct responses (PC) was assessed based on 10 trials of each reader for each object type, size and imaging modality. Additionally, detection threshold diameters at 62.5 PC were assessed via non-linear regression fitting of the psychometric curve. The reproducibility study showed no significant differences in PC values. Evaluation of target detection in FFDM showed that microcalcification detection thresholds ranged between 110 and 118 µm and were similar compared to the detection in DBT (range of 106–158 µm). In DBT, detection of both mass types increased significantly (p = 0.0001 and p = 0.0002 for non-spiculated and spiculated masses respectively) compared to FFDM, achieving almost 100% detection for all spiculated mass diameters.In conclusion, a structured phantom with inserted targets was able to show evidence for detectability differences between FFDM and DBT modes for five commercial systems. This phantom has potential for application in task-based assessment at acceptance and commissioning testing of DBT systems.

Diagnostic performance of digital breast tomosynthesis with a wide scan angle compared to full-field digital mammography for the detection and characterization of microcalcifications

ObjectivesTo assess the diagnostic performance of digital breast tomosynthesis (DBT), with a wide scan-angle, compared to full-field digital mammography (FFDM), for the detection and characterization of microcalcifications. MethodsIRB approval was obtained for this retrospective study. We selected 150 FFDM and DBT (50 benign and 50 malignant histologically verified microcalcifications, 50 cases classified as BI-RADS 1). Four radiologists evaluated, in separate sessions and blinded to patients’ history and histology, the presence of microcalcifications. Cases with microcalcifications were assessed for visibility, characteristics, and grade of suspicion using BI-RADS categories. Detection rate and diagnostic performance were calculated. Visibility, lesions’ characteristics and reading time were analysed. ResultsDetection rate and visibility were good for both FFDM and DBT, without intra-reader differences (P=0.510). Inter-reader differences were detected (P<0.018). Only two lesions were not detected by any reader on either FFDM or DBT. Diagnostic performance with DBT was as good as that of FFDM, but a significant inter-reader difference was found (P=0.041). High inter-reader variability in the use of the descriptors was found. Reading time for DBT was almost twice that for FFDM (44 and 25s, respectively). ConclusionWide scan-angle DBT enabled the detection and characterization of microcalcifications with no significant differences from FFDM. Inter-reader variability was seen.

Digital breast tomosynthesis as an adjunct to digital mammography for detecting and characterising invasive lobular cancers: a multi-reader study

To examine the interpretive performance of digital breast tomosynthesis (DBT) as an adjunct to digital mammography (DM) compared to DM alone in a series of invasive lobular carcinomas (ILCs) and to assess whether DBT can be used to characterise ILC. A retrospective, multi-reader study was conducted of 83 mammographic examinations of women with 107 newly diagnosed ILCs ascertained at histology. Consenting women underwent both DM and DBT acquisitions. Twelve radiologists, with varying mammography experience, interpreted DM images alone, reporting lesion location, mammographic features, and malignancy probability using the Breast Imaging-Reporting and Data System (BI-RADS) categories 1-5; they then reviewed DBT images in addition to DM, and reported the same parameters. Statistical analyses compared sensitivity, false-positive rates (FPR), and interpretive performance using the receiver operating characteristics (ROC) curve and the area under the curve (AUC), for reading with DM versus DM plus DBT. Multi-reader pooled ROC analysis for DM plus DBT yielded AUC=0.89 (95% confidence interval [CI]: 0.88-0.91), which was significantly higher (p<0.0001) than DM alone with AUC=0.84 (95% CI: 0.82-0.86). DBT plus DM significantly increased pooled sensitivity (85%) compared to DM alone (70%; p<0.0001). FPR did not vary significantly with the addition of DBT to DM. Interpreting with DBT (compared to DM alone) increased the correct identification of ILCs depicted as architectural distortions (84% versus 65%, respectively) or as masses (89% versus 70%), increasing interpretive performance for both experienced and less-experienced readers; larger gains in AUC were shown for less-experienced radiologists. Multifocal and/or multicentric and bilateral disease was more frequently identified on DM with DBT. Adding DBT to DM significantly improved the accuracy of mammographic interpretation for ILCs and contributed to characterising disease extent.

B.259 - Image quality in digital breast tomosynthesis: A phantom assessment

Introduction: The authors investigated the imaging performance of Digital Breast Tomosynthesis (DBT) in terms of spatial linearity, visibility of microcalcifications (m-c) and the dose-normalized contrast to noise ratio (CNRD) of masses in a 3D breast phantom, with respect to digital mammography (DM).

Development and experience of quality control methods for digital breast tomosynthesis systems.

To develop tomosynthesis quality control (QC) test methods and use them alongside established two-dimensional (2D) QC tests to measure the performance of digital breast tomosynthesis (DBT) systems used in a comparative trial with 2D mammography. DBT QC protocols and associated analysis were developed, incorporating adaptions of some 2D tests as well as some novel tests. The tomosynthesis tests were: mean glandular dose to the standard breast model; contrast-to-noise ratio in reconstructed focal planes; geometric distortion; artefact spread; threshold contrast detail detection in reconstructed focal planes, alignment of the X-ray beam to the reconstructed image and missed tissue; reproducibility of the tomosynthesis exposure; and homogeneity of the reconstructed focal planes. Summaries of results from the tomosynthesis QC tests are presented together with some 2D results for comparison. The tomosynthesis QC tests and analysis methods developed were successfully applied. The lessons learnt, which are detailed in the Discussion section, may be helpful to others embarking on DBT QC programmes. DBT performance test equipment and analysis methods have been developed. The experience gained has contributed to the subsequent drafting of DBT QC protocols in the UK and Europe.

Factors affecting recall rate and false positive fraction in breast cancer screening with breast tomosynthesis – A statistical approach

In this study, we investigate which factors affect the false positive fraction (FPF) for digital breast tomosynthesis (DBT) compared to digital mammography (DM) in a screening population by using classification and regression trees (C&RT) and binary marginal generalized linear models.The data was obtained from the Malmö Breast Tomosynthesis Screening Trial, which aimed to compare the performance of DBT to DM in breast cancer screening. By using data from the first half of the study population (7500 women), a tree with the recall probability for different groups was calculated. The effect of age and breast density on the FPF was estimated using a binary marginal generalized linear model.Our results show that breast density and breast cancer were the main factors influencing recall. The FPF is mainly affected by breast density and increases with breast density for DBT and DM.In conclusion, the results obtained with C&RT are easy to interpret and similar to those obtained using binary marginal generalized linear models. The FPF is approximately 40% higher for DBT compared to DM for all breast density categories.

Dosimetric characterization and organ dose assessment in digital breast tomosynthesis: Measurements and Monte Carlo simulations using voxel phantoms.

Due to its capability to more accurately detect deep lesions inside the breast by removing the effect of overlying anatomy, digital breast tomosynthesis (DBT) has the potential to replace the standard mammography technique in clinical screening exams. However, the European Guidelines for DBT dosimetry are still a work in progress and there are little data available on organ doses other than to the breast. It is, therefore, of great importance to assess the dosimetric performance of DBT with respect to the one obtained with standard digital mammography (DM) systems. The aim of this work is twofold: (i) to study the dosimetric properties of a combined DBT/DM system (MAMMOMAT Inspiration Siemens(®)) for a tungsten/rhodium (W/Rh) anode/filter combination and (ii) to evaluate organs doses during a DBT examination. For the first task, measurements were performed in manual and automatic exposure control (AEC) modes, using two homogeneous breast phantoms: a PMMA slab phantom and a 4 cm thick breast-shaped rigid phantom, with 50% of glandular tissue in its composition. Monte Carlo (MC) simulations were performed using Monte Carlo N-Particle eXtended v.2.7.0. A MC model was implemented to mimic DM and DBT acquisitions for a wide range of x-ray spectra (24 -34 kV). This was used to calculate mean glandular dose (MGD) and to compute series of backscatter factors (BSFs) that could be inserted into the DBT dosimetric formalism proposed by Dance et al. Regarding the second aim of the study, the implemented MC model of the clinical equipment, together with a female voxel phantom ("Laura"), was used to calculate organ doses considering a typical DBT acquisition. Results were compared with a standard two-view mammography craniocaudal (CC) acquisition. Considering the AEC mode, the acquisition of a single CC view results in a MGD ranging from 0.53 ± 0.07 mGy to 2.41 ± 0.31 mGy in DM mode and from 0.77 ± 0.11 mGy to 2.28 ± 0.32 mGy in DBT mode. Regarding the BSF, the results achieved may lead to a MGD correction of about 6%, contributing to the improvement of the current guidelines used in these applications. Finally, considering the MC results obtained for the organ dose study, the radiation doses found for the tissues of the body other than the breast were in the range of tens of μSv, and are in part comparable to the ones obtained in standard DM. Nevertheless, in a single DBT examination, some organs (such as lung and thyroid) receive higher doses (of about 9% and 21%, respectively) with respect to the CC DM acquisition. Taking into account an average breast with a thickness of 4.5 cm, the MGDs for DM and DBT acquisitions were below the achievable value (2.0 mGy) defined by the European protocol. Additionally, in the case of a fusion imaging study (DM + DBT), the MGD for a 4.5 cm thick breast is of the order of 1.88 ± 0.36 mGy. Finally, organ dose evaluations underline the need to improve awareness concerning dose estimation of DBT exams for some organs, especially when radiation risk is assessed by using the effective dose.

The TOMMY trial: a comparison of TOMosynthesis with digital MammographY in the UK NHS Breast Screening Programme--a multicentre retrospective reading study comparing the diagnostic performance of digital breast tomosynthesis and digital mammography with digital mammography alone.

Digital breast tomosynthesis (DBT) is a three-dimensional mammography technique with the potential to improve accuracy by improving differentiation between malignant and non-malignant lesions. The objectives of the study were to compare the diagnostic accuracy of DBT in conjunction with two-dimensional (2D) mammography or synthetic 2D mammography, against standard 2D mammography and to determine if DBT improves the accuracy of detection of different types of lesions. Women (aged 47-73 years) recalled for further assessment after routine breast screening and women (aged 40-49 years) with moderate/high of risk of developing breast cancer attending annual mammography screening were recruited after giving written informed consent. All participants underwent a two-view 2D mammography of both breasts and two-view DBT imaging. Image-processing software generated a synthetic 2D mammogram from the DBT data sets. In an independent blinded retrospective study, readers reviewed (1) 2D or (2) 2D + DBT or (3) synthetic 2D + DBT images for each case without access to original screening mammograms or prior examinations. Sensitivities and specificities were calculated for each reading arm and by subgroup analyses. Data were available for 7060 subjects comprising 6020 (1158 cancers) assessment cases and 1040 (two cancers) family history screening cases. Overall sensitivity was 87% [95% confidence interval (CI) 85% to 89%] for 2D only, 89% (95% CI 87% to 91%) for 2D + DBT and 88% (95% CI 86% to 90%) for synthetic 2D + DBT. The difference in sensitivity between 2D and 2D + DBT was of borderline significance (p = 0.07) and for synthetic 2D + DBT there was no significant difference (p = 0.6). Specificity was 58% (95% CI 56% to 60%) for 2D, 69% (95% CI 67% to 71%) for 2D + DBT and 71% (95% CI 69% to 73%) for synthetic 2D + DBT. Specificity was significantly higher in both DBT reading arms for all subgroups of age, density and dominant radiological feature (p < 0.001 all cases). In all reading arms, specificity tended to be lower for microcalcifications and higher for distortion/asymmetry. Comparing 2D + DBT to 2D alone, sensitivity was significantly higher: 93% versus 86% (p < 0.001) for invasive tumours of size 11-20 mm. Similarly, for breast density 50% or more, sensitivities were 93% versus 86% (p = 0.03); for grade 2 invasive tumours, sensitivities were 91% versus 87% (p = 0.01); where the dominant radiological feature was a mass, sensitivities were 92% and 89% (p = 0.04) For synthetic 2D + DBT, there was significantly (p = 0.006) higher sensitivity than 2D alone in invasive cancers of size 11-20 mm, with a sensitivity of 91%. The specificity of DBT and 2D was better than 2D alone but there was only marginal improvement in sensitivity. The performance of synthetic 2D appeared to be comparable to standard 2D. If these results were observed with screening cases, DBT and 2D mammography could benefit to the screening programme by reducing the number of women recalled unnecessarily, especially if a synthetic 2D mammogram were used to minimise radiation exposure. Further research is required into the feasibility of implementing DBT in a screening setting, prognostic modelling on outcomes and mortality, and comparison of 2D and synthetic 2D for different lesion types. Current Controlled Trials ISRCTN73467396. This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 4. See the HTA programme website for further project information.

TU-F-18C-02: Increasing Amorphous Selenium Thickness in Direct Conversion Flat-Panel Imagers for Contrast-Enhanced Dual-Energy Breast Imaging

Purpose: Contrast-enhanced (CE) breast imaging using iodinated contrast agents requires imaging with x-ray spectra at energies greater than those used in mammography. Optimizing amorphous selenium (a-Se) flat panel imagers (FPI) for this higher energy range may increase lesion conspicuity. Methods: We compare imaging performance of a conventional FPI with 200 μm a-Se conversion layer to a prototype FPI with 300 μm a-Se layer. Both detectors are evaluated in a Siemens MAMMOMAT Inspiration prototype digital breast tomosynthesis (DBT) system using low-energy (W/Rh 28 kVp) and high-energy (W/Cu 49 kVp) x-ray spectra. Detectability of iodinated lesions in dual-energy images is evaluated using an iodine contrast phantom. Effects of beam obliquity are investigated in projection and reconstructed images using different reconstruction methods. The ideal observer signal-to-noise ratio is used as a figure-of-merit to predict the optimal a-Se thickness for CE lesion detectability without compromising conventional full-field digital mammography (FFDM) and DBT performance. Results: Increasing a-Se thickness from 200 μm to 300 μm preserves imaging performance at typical mammographic energies (e.g. W/Rh 28 kVp), and improves the detective quantum efficiency (DQE) for high energy (W/Cu 49 kVp) by 30%. While the more penetrating high-energy x-ray photons increase geometric blur due to beam obliquity in the FPI with thicker a-Se layer, the effect on lesion detectability in FBP reconstructions is negligible due to the reconstruction filters employed. Ideal observer SNR for CE objects shows improvements in in-plane detectability with increasing a-Se thicknesses, though small lesion detectability begins to degrade in oblique projections for a-Se thickness above 500 μm. Conclusion: Increasing a-Se thickness in direct conversion FPI from 200 μm to 300 μm improves lesion detectability in CE breast imaging with virtually no cost to conventional FFDM and DBT. This work was partially supported by a research grant from Siemens Healthcare.

X‐ray scatter correction in breast tomosynthesis with a precomputed scatter map library

To develop and evaluate the impact on lesion conspicuity of a software-based x-ray scatter correction algorithm for digital breast tomosynthesis (DBT) imaging into which a precomputed library of x-ray scatter maps is incorporated. A previously developed model of compressed breast shapes undergoing mammography based on principal component analysis (PCA) was used to assemble 540 simulated breast volumes, of different shapes and sizes, undergoing DBT. A Monte Carlo (MC) simulation was used to generate the cranio-caudal (CC) view DBT x-ray scatter maps of these volumes, which were then assembled into a library. This library was incorporated into a previously developed software-based x-ray scatter correction, and the performance of this improved algorithm was evaluated with an observer study of 40 patient cases previously classified as BI-RADS® 4 or 5, evenly divided between mass and microcalcification cases. Observers were presented with both the original images and the scatter corrected (SC) images side by side and asked to indicate their preference, on a scale from -5 to +5, in terms of lesion conspicuity and quality of diagnostic features. Scores were normalized such that a negative score indicates a preference for the original images, and a positive score indicates a preference for the SC images. The scatter map library removes the time-intensive MC simulation from the application of the scatter correction algorithm. While only one in four observers preferred the SC DBT images as a whole (combined mean score = 0.169 ± 0.37, p > 0.39), all observers exhibited a preference for the SC images when the lesion examined was a mass (1.06 ± 0.45, p < 0.0001). When the lesion examined consisted of microcalcification clusters, the observers exhibited a preference for the uncorrected images (-0.725 ± 0.51, p < 0.009). The incorporation of the x-ray scatter map library into the scatter correction algorithm improves the efficiency of the algorithm. The observer study presented here is also the first test of the scatter correction algorithm with patient images and human observers, and demonstrates its potential to improve the clinical performance of DBT.

Reply to Letter to the Editor re: Diagnostic accuracy of digital breast tomosynthesis versus digital mammography for benign and malignant lesions in breasts: a meta-analysis

Dear Editor, We were very pleased to receive your letter and appreciate the opportunity to respond to the concern raised about our article [1]. One of our criteria for pooling the data was that digital breast tomosynthesis (DBT) and digital mammography (DM) were used as the reference for diagnosing breast lesions. However, we placed no limitation on whether DBT was performed in one-view or two-view mode; so in agreement with the aforementioned letter, Michell et al. [2], Teerstra et al. [3] and Gur et al. [4] comparedDBT in two views versus DM. The other four studies [5–8] compared DBT in one view versus DM.We did not present this information in our article because the studies satisfied the criterion mentioned above, i.e. they were characterised as using DBT. Moreover, the heterogeneity analysis which we investigated as a possible factor in the oneview or two-view mode in the meta-regression analysis failed to provide any evidence of heterogeneity. Our prime objective was to evaluate the diagnostic performance of DBT and DM for benign and malignant lesions in breasts. Wementioned that “the present study usedmeta-analysis to evaluate whether there was a higher diagnostic accuracy of one-view DBTand two-view DM relative to the gold standard in breast lesions in the discussion part”. Table 1 shows the sensitivity and specificity of one-view or two-view DBT vs gold standard. We appreciate that the sensitivity and specificity of two-view DBT are higher than those of one-view DBT, but in consideration of certain factors, including cost, radiation dose, and discomfort for patients [9–11], we still maintain the conclusion that one-view DBT has a high sensitivity and specificity for the diagnosis of benign and malignant lesions in breasts [9]. Again, we would like to thank European Radiology for publishing our original article and the opportunity to clarify the diagnostic accuracy of DBT versus DM for benign and malignant breast lesions.

Diagnostic accuracy of digital breast tomosynthesis versus digital mammography for benign and malignant lesions in breasts: a meta-analysis

To evaluate the diagnostic performance of digital breast tomosynthesis (DBT) and digital mammography (DM) for benign and malignant lesions in breasts. Document retrieval was conducted on PubMed, EMBASE, the Cochrane Library, Web of Science and Chinese Biomedical Literature Database, etc., from 1950 to June 2013. Metadisc1.4 software was used to analyse the pooled sensitivity, specificity, diagnostic odds ratio (DOR), and positive and negative likelihood ratio. The heterogeneity was assessed using forest plots and the inconsistency index (I(2)). Before statistical comparison, the area under (AUC) the summary receiver-operating characteristic curve (SROC) of two different diagnostic methods was calculated respectively. A total of seven studies involving 2,014 patients and 2,666 breast lesions were included. Compared with the gold standard (histological results), the pooled sensitivity and specificity of DBT were 90.0% and 79.0%, and for DM they were 89.0% and 72.0%, respectively. The pooled positive likelihood ratio of DBT and DM was 3.50 and 2.83; the pooled negative likelihood ratio of DBT and DM was 15% and 18%; the pooled DOR for DBT and DM was 26.04 and 16.24, respectively. Digital breast tomosynthesis has a higher sensitivity and specificity in breast diagnosis than digital mammography. • Digital breast tomosynthesis has high sensitivity and specificity in breast diagnosis.• DBT appears to have superior diagnostic accuracy relative to digital mammography. • DBT images were captured at a lower dose than 2D images. • DBT displays abnormal features of lesions more clearly than DM. • Digital breast tomosynthesis could become the first choice for assessing breast lesions.

The Adjunctive Digital Breast Tomosynthesis in Diagnosis of Breast Cancer

Purpose. To compare the diagnostic performance of digital breast tomosynthesis (DBT) and digital mammography (DM) for breast cancers. Materials and Methods. Fifty-seven female patients with pathologically proved breast cancer were enrolled. Three readers gave a subjective assessment superiority of the index lesions (mass, focal asymmetry, architectural distortion, or calcifications) and a forced BIRADS score, based on DM reading alone and with additional DBT information. The relevance between BIRADS category and index lesions of breast cancer was compared by chi-square test. Result. A total of 59 breast cancers were reviewed, including 17 (28.8%) mass lesions, 12 (20.3%) focal asymmetry/density, 6 (10.2%) architecture distortion, 23 (39.0%) calcifications, and 1 (1.7%) intracystic tumor. Combo DBT was perceived to be more informative in 58.8% mass lesions, 83.3% density, 94.4% architecture distortion, and only 11.6% calcifications. As to the forced BIRADS score, 84.4% BIRADS 0 on DM was upgraded to BIRADS 4 or 5 on DBT, whereas only 27.3% BIRADS 4A on DM was upgraded on DBT, as BIRADS 4A lesions were mostly calcifications. A significant P value (<0.001) between the BIRADS category and index lesions was noted. Conclusion. Adjunctive DBT gives exquisite information for mass lesion, focal asymmetry, and/or architecture distortion to improve the diagnostic performance in mammography.

TOMMY Trial (a comparison of tomosynthesis with digital mammography in the UK NHS breast screening programme) setting up a multicentre imaging trial

Digital breast tomosynthesis (DBT) has the potential to improve the accuracy of standard digital mammography (DM) [1]. The TOMMY Trial is a multicentre, multireader, retrospective matched comparison of the diagnostic performance of DBT and DM.