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Digital Breast Tomosynthesis: A Pilot Observer Study
Abstract
The objective of our study was to assess ergonomic and diagnostic performance-related issues associated with the interpretation of digital breast tomosynthesis-generated examinations.
Thirty selected cases were read under three different display conditions by nine experienced radiologists in a fully crossed, mode-balanced observer performance study. The reading modes included full-field digital mammography (FFDM) alone, the 11 low-dose projections acquired for the reconstruction of tomosynthesis images, and the reconstructed digital breast tomosynthesis examination. Observers rated cases under the free-response receiver operating characteristic, as well as a screening paradigm, and provided subjective assessments of the relative diagnostic value of the two digital breast tomosynthesis-based image sets as compared with FFDM. The time to review and diagnose each case was also evaluated.
Observer performance measures were not statistically significant (p > 0.05) primarily because of the small sample size in this pilot study, suggesting that showing significant improvements in diagnosis, if any, will require a larger study. Several radiologists did perceive the digital breast tomosynthesis image set and the projection series to be better than FFDM (p < 0.05) for diagnosing this specific case set. The time to review, interpret, and rate the examinations was significantly different for the techniques in question (p < 0.05).
Tomosynthesis-based breast imaging may have great potential, but much work is needed before its optimal role in the clinical environment is known.
... 3 Digital breast tomosynthesis (DBT) (Fig. 1), a pseudothree-dimensional X-ray imaging technique, has recently been integrated into clinical use. The results of several pilot studies [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] and trials 15, 16,24,25 have suggested that DBT not only has the potential to substantially eliminate the tissue 'overlap effect' 1 but also can potentially reduce recall rates at screening (~17%), 4,14,15,21 improve lesion visibility, 4,[6][7][8]10,19,21 increase cancer detection (~51% (total), 15 40% (invasive cancers) 26,27 ), increase diagnostic accuracy 13,14 and improve patient comfort. 1,28 Most of the above studies focused primarily on the use of DBT for breast cancer screening. ...
... 3 Digital breast tomosynthesis (DBT) (Fig. 1), a pseudothree-dimensional X-ray imaging technique, has recently been integrated into clinical use. The results of several pilot studies [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] and trials 15, 16,24,25 have suggested that DBT not only has the potential to substantially eliminate the tissue 'overlap effect' 1 but also can potentially reduce recall rates at screening (~17%), 4,14,15,21 improve lesion visibility, 4,[6][7][8]10,19,21 increase cancer detection (~51% (total), 15 40% (invasive cancers) 26,27 ), increase diagnostic accuracy 13,14 and improve patient comfort. 1,28 Most of the above studies focused primarily on the use of DBT for breast cancer screening. ...
... Several assessment-based studies [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]27,37 have been conducted to compare the performance of DBT with Figure 1. Schematic of standard digital breast tomosynthesis (DBT) system where an X-ray source moves in an arc and steps and shoots an X-ray beam that falls on the breast compressed between the compression paddle and the support plate. ...
Mammography has long been considered as the primary technique in breast cancer detection and assessment. Despite low specificity, mammography has been preferred over other contemporary techniques such as magnetic resonance imaging (MRI), computed tomography (CT) and ultrasonography (US) due to superior sensitivity and significant health economic benefits. The development of a new technique, a limited angle cone beam pseudo-three-dimensional tomosynthesis, digital breast tomosynthesis (DBT), has gained momentum. Several preliminary studies and ongoing trials are showing evidence of the benefits of DBT in improving lesion visibility, accuracy of cancer detection and observer performance. This raises the possibility of adoption of DBT in the breast cancer assessment clinic, wherein confirming or dismissing the presence of malignancy (at the potential site identified during screening) is of utmost importance. Identification of suspected malignancy in terms of lesion characteristics and location is also essential in assessment. In this literature review, we evaluate the role of DBT for use in breast cancer assessment and its future in biopsy.
... Skaane et al. demonstrated the mean interpretation time as 45 seconds for mammography alone and 91 seconds for mammography plus DBT [21]. Additionally, two retrospective studies by Good et al. and Gur et al. showed the time to interpret examinations using DBT alone or full-field digital mammography plus DBT combined was longer than when interpreting mammography [26,27]. However, many breast screening centers have incorporated the use of DBT into routine screening protocols, even if optimization of interpretation efficiency is still needed. ...
... Good et al. [26] Digital breast tomosynthesis: a pilot observer study 2008 ...
The number one cause of cancer in women worldwide is breast cancer. Over the last three decades, the use of traditional screen-film mammography has increased, but in recent years, digital mammography and 3D tomosynthesis have become standard procedures for breast cancer screening. With the advancement of technology, the interpretation of images using automated algorithms has become a subject of interest. Initially, computer-aided detection (CAD) was introduced; however, it did not show any long-term benefit in clinical practice. With recent advances in artificial intelligence (AI) methods, these technologies are showing promising potential for more accurate and efficient automated breast cancer detection and treatment. While AI promises widespread integration in breast cancer detection and treatment, challenges such as data quality, regulatory, ethical implications, and algorithm validation are crucial. Addressing these is essential for fully realizing AI's potential in enhancing early diagnosis and improving patient outcomes in breast cancer management. In this review article, we aim to provide an overview of the latest developments and applications of AI in breast cancer screening and treatment. While the existing literature primarily consists of retrospective studies, ongoing and future prospective research is poised to offer deeper insights. Artificial intelligence is on the verge of widespread integration into breast cancer detection and treatment, holding the potential to enhance early diagnosis and improve patient outcomes.
... 7 If DBT is read together with DM or synthetic mammogram, the increase has been between 73% and 319%. [4][5][6][7] To the best of our knowledge, no study of reading time for one-view DBT compared with two-view DM is available. However, two studies reported reading times of one sided one-view wide-angle DBT. ...
... 8,9 These times were similar to the DBT reading times in some of the studies comparing one-sided two-view DBT with DM, 6,7 but shorter than some of the studies. 4,5 Thus, the reading time of one-view wide-angle DBT might be slightly shorter than two-view DBT, but still longer than two-view DM; however, comparison between studies might be complicated due to different study designs. The longer reading time, together with the limited availability of equipment and higher total cost for DBT, are all barriers for a wider implementation. ...
Purpose:
Breast cancer screening is predominantly performed using digital mammography (DM), but digital breast tomosynthesis (DBT) has higher sensitivity. DBT demands more resources than DM, and it might be more feasible to reserve DBT for women with a clear benefit from the technique. We explore if artificial intelligence (AI) can select women who would benefit from DBT imaging.
Approach:
We used data from Malmö Breast Tomosynthesis Screening Trial, where all women prospectively were examined with separately double read DM and DBT. We retrospectively analyzed DM examinations (n=14768) with a breast cancer detection system and used the provided risk score (1 to 10) for risk stratification. We tested how different score thresholds for adding DBT to an initial DM affects the number of detected cancers, additional DBT examinations needed, detection rate, and false positives.
Results:
If using a threshold of 9.0, 25 (26%) more cancers would be detected compared to using DM alone. Of the 41 cancers only detected on DBT, 61% would be detected, with only 1797 (12%) of the women examined with both DM and DBT. The detection rate for the added DBT would be 14/1000 women, whereas the false-positive recalls would be increased with 58 (21%).
Conclusion:
Using DBT only for selected high gain cases could be an alternative to complete DBT screening. AI can analyze initial DM images to identify high gain cases where DBT can be added during the same visit. There might be logistical challenges, and further studies in a prospective setting are necessary.
... In terms of AUC, a non-statistically significant difference between the performances of DM and DBT for Hologic, was found in two studies, 19,30 showing that the two imaging systems could equally distinguish between a cancerous and a non-cancerous group. Conflicting results were found by Seo et al 2016. ...
... Conflicting results were found by Seo et al 2016. 16 Larger studies are required to support these studies' results and draw final conclusions on AUC, as their sample number is relatively small (30, 100 and 203 patients for 16,19,30 respectively). Regarding architectural distortions, Dibbie et al 26 have shown a higher AUC with DBT alone compared to DM. ...
Aim
Digital Breast Tomosynthesis (DBT), with or without Digital Mammography (DM) or Synthetic Mammography (SM), has been introduced or is under consideration for its introduction in breast cancer screening in several countries, as it has been shown that it has advantages over DM. Despite this there is no agreement on how to implement DBT in screening, and in many cases there is a lack of official guidance on the optimum usage of each commercially available system. The aim of this review is to carry out a manufacturer-specific summary of studies on the implementation of DBT in breast cancer screening.
Methods
An exhaustive literature review was undertaken to identify clinical observer studies that evaluated at least one of five common metrics: sensitivity, specificity, area under the curve (AUC) of the receiver-operating characteristics (ROC) analysis, recall rate and cancer detection rate. Four common DBT implementation methods were discussed in this review: (1) DBT, (2) DM with DBT, (3) 1-view DBT with or without 1-view DM or 2-view DM and (4) DBT with SM.
Results
A summary of 89 studies, selected from a database of 677 studies, on the assessment of the implementation of DBT in breast cancer screening is presented in tables and discussed in a manufacturer- and metric-specific approach. Much more studies were carried out using some DBT systems than others. For one implementation method of DBT by one manufacturer there is a shortage of studies, for another implementation there are conflicting results. In some cases, there is a strong agreement between studies, making the advantages and disadvantages of each system clear.
Conclusion
The optimum implementation method of DBT in breast screening, in terms of diagnostic benefit and patient radiation dose, for one manufacturer does not necessarily apply to other manufacturers.
... However, many life-critical search tasks involve large datasets, preventing observers from realistically scrutinizing all image regions (79,80). Radiologists are increasingly using 3D volumetric imaging consisting of a large number of X-ray slices per scan: 64-128 slices for computed tomography (83) and 50-90 slices for digital breast tomosynthesis (DBT) (84)(85)(86). Based on clinical reading times of 2-3 min per case (84,85) and 250-350 ms per fixation, radiologists would average no more than 14.4 fixations per slice when inspecting one DBT scan (3 min of 250 ms per fixation across 50 slices for one breast) and possibly as little as 1.9 fixations per slice when inspecting a separate DBT scan for each breast (2 min of 350 ms per fixation across 180 total slices for both breasts). ...
... Radiologists are increasingly using 3D volumetric imaging consisting of a large number of X-ray slices per scan: 64-128 slices for computed tomography (83) and 50-90 slices for digital breast tomosynthesis (DBT) (84)(85)(86). Based on clinical reading times of 2-3 min per case (84,85) and 250-350 ms per fixation, radiologists would average no more than 14.4 fixations per slice when inspecting one DBT scan (3 min of 250 ms per fixation across 50 slices for one breast) and possibly as little as 1.9 fixations per slice when inspecting a separate DBT scan for each breast (2 min of 350 ms per fixation across 180 total slices for both breasts). Similarly, the increasing amounts of surveillance photographs taken across space and time by unmanned aerial vehicles and ever-cheaper quadcopters might not permit geospatial analysts to thoroughly fixate all aerial image regions for a case. ...
Significance
Simple majority voting is a widespread, effective mechanism to exploit the wisdom of crowds. We explored scenarios where, from decision to decision, a varying minority of group members often has increased information relative to the majority of the group. We show how this happens for visual search with large image data and how the resulting pooling benefits are greater than previously thought based on simpler perceptual tasks. Furthermore, we show how simple majority voting obtains inferior benefits for such scenarios relative to averaging people’s confidences. These findings could apply to life-critical medical and geospatial imaging decisions that require searching large data volumes and, more generally, to any decision-making task for which the minority of group members with high expertise varies across decisions.
... In a screening trial of 1,208 women, Gennaro, Bernardi and Houssami [11] found DBT doses to be 38% higher with a range from no difference up to 75%. Other authors have found DBT doses equal to [12] or even lower [13] than FFDM. The aims of this study are to present the latest NHSBSP dose survey results and compare DBT and FFDM doses within the programmes. ...
Objective
To report the latest UK mammography dose survey results and to compare radiation doses from digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM) in UK breast screening.
Methods
Anonymised exposure factors were collected for 111,152 screening cases and 5,113 assessment cases from 405 x-ray sets across the UK using an online submission system linked to a national database of mammography quality control data. Output and beam quality measurements from each set were combined with exposure data to estimate mean glandular doses (MGD).
Results
FFDM doses increased by approximately 10% compared to the 2016-2019 national survey but compressed breast thicknesses (CBT) remained similar. DBT doses were 44-49% higher than FFDM overall and 34% higher than FFDM for breasts 50-60mm thick. We found a possible overestimation of PMMA breast equivalent thicknesses at low CBTs, but the evidence was not conclusive.
Conclusion
Recent changes to the mix of x-ray models in use in UK breast screening have resulted in higher FFDM breast doses. DBT doses in the NHSBSP are on average higher than FFDM by approximately 44% to 49%.
Advances in knowledge
This is the first national study to report DBT and FFDM MGDs in UK breast screening.
... DBT volume data can be analyzed in depth through several 2D slices (standard visualization slice-by-slice). This multislice inspection leads to a longer analysis time (because instead of two images, radiologists have to inspect an average of sixty images per patient), which represent a problem in daily practice and screening environment (Caumo et al., 2018;Good et al., 2008;Gur et al., 2009). ...
Microcalcification clusters (MCs) are one of the most important biomarkers for breast cancer and Digital Breast Tomosynthesis (DBT) has consolidated its role in breast cancer imaging. As there are mixed observations about MCs detection using DBT, it is important to develop tools that improve this task. Furthermore, the visualization mode of MCs is also crucial, as their diagnosis is associated with their 3D morphology. In this work, DBT data from a public database were used to train a faster region-based convolutional neural network (R-CNN) to locate MCs in entire DBT. Additionally, the detected MCs were further analyzed through standard 2D visualization and 3D volume rendering (VR) specifically developed for DBT data. For MCs detection, the sensitivity of our Faster R-CNN was 60% with 4 false positives. These preliminary results are very promising and can be further improved. On the other hand, the 3D VR visualization provided important information, with higher quality and discernment of the detected MCs. The developed pipeline may help radiologists since (1) it indicates specific breast regions with possible lesions that deserve additional attention and (2) as the rendering of the MCs is similar to a segmentation, a detailed complementary analysis of their 3D morphology is possible.
... The thin slices of DBT acquisition and the removal of superimposed breast tissue should improve lesion visibility, particularly in dense breasts and diagnostic performance; however, we did not find an improvement in reader performance. These findings are consistent with two publications that reported no association between better lesion conspicuity in DBT and diagnostic accuracy, 26,27 and suggest that regardless of the technology used to image the breast, diagnostic efficacy depends largely on the expertise of the reader who interprets the images. The two previous studies that have compared DM and DBT emphasised that DBT might have a potential impact on diagnostic performance; however, substantial training of radiologists in DBT is required to familiarise them with the appearance of different abnormalities as well as normal tissues. ...
Introduction:
Breast density is associated with an increase in breast cancer risk and limits early detection of the disease. This study assesses the diagnostic performance of mammogram readers in digital mammography (DM) and digital breast tomosynthesis (DBT).
Methods:
Eleven breast readers with 1-39 years of experience reading mammograms and 0-4 years of experience reading DBT participated in the study. All readers independently interpreted 60 DM cases (40 normal/20 abnormal) and 35 DBT cases (20 normal/15 abnormal). Sensitivity, specificity, ROC AUC, and diagnostic confidence were calculated and compared between DM and DBT.
Results:
DBT significantly improved diagnostic confidence in both dense breasts (p = 0.03) and non-dense breasts (p = 0.003) but not in other diagnostic performance metrics. Specificity was higher in DM for readers with >7 years' experience (p = 0.03) in reading mammography, non-radiologists (p = 0.04), readers who had completed a 3-6 months training fellowship in breast imaging (p = 0.04), and those with ≤2 years' experience in reading DBT (p = 0.02), particularly in non-dense breasts.
Conclusion:
Diagnostic confidence was higher in DBT when compared to DM. In contrast, other performance metrics appeared to be similar or better with DM and may be influenced by the lack of experience of the reader cohort in reading DBT.
Implications for practice:
The benefits of DBT may not be entirely accrued until radiologists attain expertise in DBT interpretation. Specificity of DBT varied according to reader characteristics, and these characteristics may be useful for optimising pairing strategies in independent double reading of DBT as practiced in Australia to reduce false positive diagnostic errors.
... It aids in reducing false positives and provides equal or better sensitivity compared with mammography and improves the specificity of mammography, especially in women with radiographically dense breasts [4][5]. Literature has shown that women subjectively prefer tomosynthesis to conventional mammography, which may offer better diagnostic accuracy for the evaluation of breast lesions [6][7][8]. ...
Introduction
Many young females present with an advanced stage of breast cancer, which has a negative effect on the prognosis. Digital breast tomosynthesis is a new emerging imaging technique that aids in improving the specificity of mammography with subsequent early detection of breast cancer, especially in women with radiographically dense breasts. Tomosynthesis is subjectively preferred to conventional mammography and may offer superior diagnostic accuracy for the evaluation of breast lesions.
Method
Two breast radiologists retrospectively reviewed asymmetric densities using protocols that were institutional review board-approved in 185 patients aged 18 - 70 years (mean: 48 years) who underwent diagnostic mammography and tomosynthesis. Each asymmetric density was interpreted once with tomosynthesis and once with supplemental mammographic views; both modes included the mediolateral oblique and craniocaudal views in a fully crossed and balanced design by using a five-category Breast Imaging Reporting and Data System (BI-RADS) assessment and a probability-of-malignancy score. If the abnormality persisted and appeared benign or completely disappeared on both modalities, the agreement between additional views and tomosynthesis was determined by calculating Kappa value. If there was a discrepancy between additional views and tomosynthesis, the abnormality was subjected to ultrasound. In our study, 89 asymmetric densities were subjected to ultrasound.
Results
In a total of 182 cases, 84 (46.15%) were categorized as BIRADS-0; 97 (53.30 %) as BIRADS-I, and one (0.55 %) as BIRADS-II on an additional view. Among the asymmetric densities categorized as BIRADS-0 on additional mammography views, digital breast tomosynthesis categorized 72, six, five, and one patient as BIRADS-0, BIRADS-I, BIRADS-II, and BIRADS-IV, respectively. For densities categorized as BIRADS-I (97) on additional view, digital breast tomosynthesis categorized 10 and 87 densities as BIRADS-0 and BIRADS-I, respectively.
No change in the BIRADS category was observed among BIRADS-II and BIRADS-IV.
A significant difference was observed with the chi-square test among BIRADS categories assigned by an additional view and digital breast tomosynthesis with a p-value of < 0.001. There was, however, a substantial agreement among additional views and tomosynthesis with a kappa value of 0.767.
Conclusion
Our study results suggest that tomosynthesis may be equivalent to, if not more equivalent to, additional imaging in the assessment of mammographically-detected asymmetric densities, thus improving BI-RADS classification and patient management.
... Currently, DBT images are analyzed with a two dimensional (2D) slice-by-slice visualization [8]. DBT presents, on average, sixty 2D slices per exam, which results in time-consuming analysis both in screening and daily clinical use [9][10][11]. Some studies have shown promising results in an attempt to reduce this time of analysis by highlighting some slices considered of interest and thus decreasing the number of slices to be analyzed [12,13]. ...
Digital Breast Tomosynthesis (DBT) presents out-of-plane artifacts caused by features of high intensity. Given observed data and knowledge about the point spread function (PSF), deconvolution techniques recover data from a blurred version. However, a correct PSF is difficult to achieve and these methods amplify noise. When no information is available about the PSF, blind deconvolution can be used. Additionally, Total Variation (TV) minimization algorithms have achieved great success due to its virtue of preserving edges while reducing image noise. This work presents a novel approach in DBT through the study of out-of-plane artifacts using blind deconvolution and noise regularization based on TV minimization. Gradient information was also included. The methodology was tested using real phantom data and one clinical data set. The results were investigated using conventional 2D slice-by-slice visualization and 3D volume rendering. For the 2D analysis, the artifact spread function (ASF) and Full Width at Half Maximum (FWHMM
ASF
) of the ASF were considered. The 3D quantitative analysis was based on the FWHM of disks profiles at 90°, noise and signal to noise ratio (SNR) at 0° and 90°. A marked visual decrease of the artifact with reductions of FWHM
ASF
(2D) and FWHM
90°
(volume rendering) of 23.8% and 23.6%, respectively, was observed. Although there was an expected increase in noise level, SNR values were preserved after deconvolution. Regardless of the methodology and visualization approach, the objective of reducing the out-of-plane artifact was accomplished. Both for the phantom and clinical case, the artifact reduction in the z was markedly visible.
... This procedure hampers the judgment of potential lesions such as clusters of microcalcification, which can be spread across several slices and difficult to interpret in a two dimensional (2D) image [12] . In addition, because in one DBT exam there are about 30 times more images than in 2D Digital Mammography (DM), the mean reading time doubles for DBT when compared with 2D DM examination [13][14][15] . Fatigue caused by the analysis of large data sets can hamper the routine functions of a radiologist. ...
... This procedure can lead to difficult interpretation of microcalcification clusters, which can be spread across several slices 5 . In addition, the mean reading time doubles for DBT compared with DM examination [6][7][8] . The time required for each DBT data set evaluation is crucial both in clinical and screening environments, directly influencing the number of examinations interpreted 8 . ...
Slice by slice visualization of Digital Breast Tomosynthesis (DBT) data is time consuming and can hamper the interpretation of lesions such as clusters of microcalcifications. With a visualization of the object through multiple angles, 3D volume rendering (VR) provides an intuitive understanding of the underlying data at once. 3D VR may play an important complementary role in breast cancer diagnosis. Transfer functions (TFs) are a critical parameter in VR and finding good TFs is a major challenge. The purpose of this work is to study a methodology to automatically generate TFs that result in appropriate and useful VR visualizations of DBT data. For intensity-based TFs, intensity histograms were used to study possible relationships between statistics and critical intensity values in DBT data. The mean of each histogram has proved to be a valid option to automatically calculate those critical values that define these functions. At this stage, eight visualizations were obtained by combining several opacity/color intensity-based functions. Considering the gradient, ten visualizations were obtained. Nine of the ten TFs were constructed considering the peaks of gradient magnitude histograms. The tenth function was a simple linear ramp. Finally, three intensity-based and three gradient-based functions were selected and simultaneously used. This resulted in nine final VR visualizations taking both information into account. The studied approach allowed an automatic generation of opacity/color TFs based on scalar intensity and gradient magnitude histograms. In this way, the preliminary results obtained with this methodology are very encouraging about creating an adequate visualization of DBT data by VR.
... Digital breast tomosynthesis was more visible and precise than another two technologies in identifying characteristics of a malignant lesion in dense breast tissue, led us to conclude that adding 3D mammography to regular screening would nd more cancers in dense breasts. Digital breast tomosynthesis, a new X-rays technology, is used for helping to solve the overlapping tissue problem since it produces a series of images with multiple low-dose tomographic images acquired in an arch [30]. These images are reconstructed and allow for visualization of the breast in multiple contiguous slices [31]. ...
Objective:
This study was to evaluate performance characteristics of ultrasonography (US) and a combined two-and three-dimensional (2D+3D) digital mammography in identifying breast tumors in Chinese women.
Subjects and methods:
One hundred and two women with suspected breast tumors were examined using diagnostic imaging techniques of US and a combined 2D+3D imaging protocol. Detection of breast tumors in women with and without dense breasts was validated according to the features of image-detected breast tumors which were proven by histological exam in this study cohort.
Results:
Breast US was superior to 2D+3D imaging in assessing benign lesions (P<0.01). The diagnostic measure on 2D+3D mammography was more accurate than the US exam in breast cancer detection. Furthermore, 2D+3D imaging was more sensitive than US in identifying malignant lesions in size of ≤1cm and in relatively high breast density (P<0.01 or 0.05). Breast US showed a better correlation with the sizes of benign tumor as compared to 2D+3D imaging with correlation coefficients of 0.930 and 0.920. Conversely, 2D+3D imaging showed a better correlation with the sizes of malignant tumors as compared to US with correlation coefficients of 0.951 and 0.815. Additionally, presence of microcalcifications on mammography significantly increased in breast cancers as compared to benign tumors (P<0.001).
Conclusion:
Breast US and 2D+3D mammography imaging play an additive role in identifying breast tumors. Intervention of the 2D+3D imaging technique helps recognize appearance and characteristics of breast lesions particularly in the women with a lesion measure of ≤1cm and those with dense breasts or breast microcalcifications.
... For example, Gur et al. (2009) examined four modalities: 2VDM, 11 projection views, 2-view BT (2VBT) and 2VDM combined with 2VBT (denoted: 2VDM + 2VBT) but results are only listed for the 2VDM + 2VBT modality. Various observer data acquisition methods were used as listed in column 3. Good et al. (2008) and Svahn et al. (2010) used the free-response method while the rest used binary or ROC-based methods. In general, BIRADS or BIRADS-based ratings were used and one study used a binary rating (i.e., recall vs. no-recall). ...
... In 1997, Nikalson et al. introduced digital breast tomosynthesis, which in a reader study of mastectomy specimens, revealed improved depiction of lesions over 2D mammograms [19]. As interest grew for this new technology, many different small reader studies were performed in the 2000s, supporting its potential as a breast imaging modality with variable reports of decreased recall rates and/or increased lesion detection [20][21][22][23]. ...
Purpose of review:
Advanced mammographic imaging modalities have been implemented in clinical practices throughout the USA. The most notable and widely used has been the three-dimensional derivative of digital mammography, known as digital breast tomosynthesis (DBT). In this article, we review the screening and diagnostic applications of DBT, along with its limitations. We also briefly address several supplemental breast imaging modalities.
Recent findings:
The accumulating evidence from both small and large-scale trials has shown a significant reduction in recall rates and slight increase in cancer detection rates when using DBT. However, the incremental increase in cancers detected remains less than that achieved with several supplemental imaging modalities, including whole-breast ultrasound, MRI, and MBI (molecular breast imaging). Other modalities, such as CEM (contrast-enhanced mammography) and CET (contrast-enhanced tomography), are also being investigated. Numerous studies have confirmed the added value of DBT and its increased cancer detection rate in both the screening and diagnostic settings. However, the superior sensitivity of supplemental imaging modalities renders them essential, especially in high-risk patients, and potentially those with dense breasts.
... The role of CDSS, will be all that more important for interpreting the 3-D imaging data. Indeed, the initial clinical observer studies conducted on breast tomosynthesis strongly suggest the utility of CADe for helping radiologists interpret the large volume of data that can be potentially generated when tomosynthesis is routinely used in clinical practice (Good et al. 2008, Gur et al. 2009). The same holds true for stereo mammography and breast CT. ...
... For example, the average time required for interpreting a DBT exam is greater than that of interpreting a 2-D mammography exam. 6,7 Thus, it is necessary to optimize DBT visualizing strategy so that 3-D information of the breast can be perceived accurately and quickly. This study focused on evaluating an entirely different approach to visualize DBT imaging data: stereoscopic viewing of DBT projection images. ...
Digital breast tomosynthesis (DBT) acquires a series of projection images from different angles as an x-ray source rotates around the breast. Such imaging geometry lends DBT naturally to stereoscopic viewing as two projection images with a reasonable separation angle can easily form a stereo pair. This simulation study assessed the efficacy of stereo viewing of DBT projection images. Three-dimensional computational breast phantoms with realistically shaped synthetic lesions were scanned by three simulated DBT systems. The projection images were combined into a sequence of stereo pairs and presented to a stereomatching-based model observer for deciding lesion presence. Signal-to-noise ratio was estimated, and the detection performance with stack viewing of reconstructed slices was the benchmark. We have shown that: (1) stereo viewing of projection images may underperform stack viewing of reconstructed slices for current DBT geometries; (2) DBT geometries may impact the efficacy of the two viewing modes differently: narrow-arc and wide-arc geometries may be better for stereo viewing and stack viewing, respectively; (3) the efficacy of stereo viewing may be more robust than stack viewing to reductions in dose. While in principle stereo viewing is potentially effective for visualizing DBT data, effective stereo viewing may require specifically optimized DBT image acquisition.
... DBT was more visible and precise than another two techologies in identifying characteristics of a malignant lesion in dense breast tissue, it led us to conclude that adding 3D mammography to regular screening would find more cancers in dense breasts. DBT, a new X-ray technology, is used for helping to solve the overlapping tissue problem since it produces a series of images with multiple low-dose tomographic images acquired in an arch [26]. These images are reconstructed and allow for visualization of the breast in multiple contiguous slices [27]. ...
... Studies also reported that DBT could be even more efficient by reducing recall rates and additional image studies. [7][8][9][10][11][12][13][14][15][16][17][18] And, several studies demonstrated that combination of DBT with FFDM was superior for cancer detection. [19][20][21] In addition to masses, architectural distortions, and asymmetries, microcalcifications are one of the most commonly appearing abnormalities in screening mammography. ...
PURPOSE
The purpose of this study is to compare the visibility of microcalcifications of digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM) using breast specimens.
MATERIALS AND METHODS
Thirty-one specimens’ DBT and FFDM were retrospectively reviewed by four readers.
RESULTS
The image quality of microcalcifications of DBT was rated as superior or equivalent in 71.0% by reader 1, 67.8% by reader 2, 64.5% by reader 3, and 80.6% by reader 4. The Fleiss kappa statistic for agreement among readers was 0.31.
CONCLUSIONS
We suggest that image quality of DBT appears to be comparable with or better than FFDM in terms of revealing microcalcifications.
... Previous studies that compared DBT with DM have shown results varying from statistically significant advantage for DBT, 10 Smith et al 14 and Michell et al,15 to no clear advantage for DBT. [16][17][18][19] However, other studies suggested improved sensitivity of DBT over DM. 5,11 It was mentioned in previous literatures initial experiences with CESM that supports its clinical feasibility. 8,10,11,20 Fallenberg et al 21 performed a comparative analysis for sizes of breast cancer measured by CESM and contrast-enhanced breast MRI. ...
Objective:
To study the role of advanced applications of digital mammogram whether contrast enhanced spectral mammography (CESM) or digital breast tomosynthesis (DBT) in the "T" staging of histologically proven breast cancer prior management planning.
Methods:
This prospective analysis, we evaluated 98 proved malignant breast masses regarding their size, multiplicity and presence of associated clusters of microcalcifications. Evaluation methods included digital mammography, 3-D tomosynthesis and contrast enhanced spectral mammography. Traditional digital mammography was first performed then in a period of 10-14 days interval; breast tomosynthesis and contrast-based mammography were done for the involved breast only. Views at tomosynthesis were acquired in a "Step-and-shoot" tube motion mode to produce multiple (11-15), low-dose images and in contrast-enhanced study: low (22-33 kVp) and high (44-49 kVp) energy exposures were taken after IV injection of contrast agent. Operative data were the gold standard reference.
Results:
Breast tomosynthesis showed the highest accuracy in size assessment (n=69, 70.4%), than contrast-enhanced (n=49, 50%) and regular mammography (n=59, 60.2%). Contrast-enhanced mammography presented the least performance in assessing calcifications, yet the most sensitive in detection of multiplicity (92.3%), followed by tomosynthesis (77%) and regular mammography (53.8%). The combined analysis of the three modalities provided accuracy of 74% in the "T" staging of breast cancer.
Conclusion:
The combined application of tomosynthesis and contrast-enhanced digital mammogram enhanced the performance of the traditional digital mammography and presented an informative method in the staging of breast cancer. Advances in knowledge: Staging and management planning of breast cancer divert according tumor size, multiplicity, and presence of microcalcifications. Digital breast tomosynthesis shows sharp outline of the tumor with no overlap tissue and spots microcalcifications. Contrast enhanced spectral mammogram shows extension of abnormal contrast uptake and detects multiplicity. Integrated analysis provides optimal findings for proper "T" staging of breast cancer.
... In an effort to overcome the limitations of 2D FFDM, digital breast tomosynthesis (DBT), which is a new three-dimensional (3D) radiographic technique, has recently been introduced. DBT allows more precise evaluation of lesions through better differentiation of overlapping tissue [7][8][9][10][11]. This modality has also demonstrated potential advantages in the evaluation of masses, areas of architectural distortion, and asymmetries compared with conventional 2D mammography. ...
Purpose
The purpose of this study was to assess the value of adding digital breast tomosynthesis (DBT) to full-field digital mammography (FFDM) in the diagnostic workup of breast cancer and to determine which lesion variables affect cancer detectability in the combined modality.
Methods
Between March and May 2012, paired FFDM and DBT images were obtained from 203 women as part of a diagnostic workup for breast cancer. Images from FFDM alone, DBT alone, and DBT combined with FFDM were reviewed in separate sessions by six blinded readers. Jackknife alternative free-response receiver operating characteristic (JAFROC) figure of merit (FOM), sensitivity, and specificity were compared between the modalities. Lesion characteristics affecting the cancer detection rate when using the combined modality were also analyzed.
Results
Among the 203 women, 126 women had a total of 129 malignancies and 77 women had total of 77 benign lesions. The overall JAFROC FOM of the combined modality was higher than that of FFDM alone (0.827 vs. 0.775, p<0.001) and that of DBT alone was higher than that of FFDM alone (0.807 vs. 0.775, p=0.027). The overall sensitivity of the combined modality was higher than that of FFDM alone (80.0% vs. 73.2%, p<0.001) and that of DBT alone was higher than that of FFDM alone (78.3% vs. 73.2%, p=0.007). Compared to FFDM alone, the combined modality detected an additional 48 cancers. Using the combined modality, the presence of masses or microcalcifications was significantly associated with the cancer detection rate (p<0.001).
Conclusion
The combination of DBT with FFDM results in a higher diagnostic yield than FFDM alone. Additionally, DBT alone performs better than FFDM alone. However, even when DBT is combined with FFDM, breast cancers with no discernible masses and those lacking calcifications are difficult to detect.
... In the Oslo study, a mean interpretation time of 45 seconds for 2D and 91 seconds for 2D+DBT was observed [10••]. Additional prior studies suggesting greater increases in interpretation time were either on prototype units with smaller volume and/or minimal DBT experience [36][37]. With more images to scroll through, it is expected that a 2D+DBT exam would take longer to read. ...
Digital 2D mammography is the current standard of care for breast cancer screening. False positives and overdiagnosis have been cited as potential harms of screening mammography, and efforts to improve this technology have led to the development of digital breast tomosynthesis (DBT). The literature thus far has shown screening with tomosynthesis to simultaneously decrease recall rates and increase cancer detection. This review evaluates the possibility for 2D plus tomosynthesis mammography to replace conventional 2D screening. It outlines the requirements of an effective screening modality, reviews early and recent literature on performance outcomes, including results by age and density, and highlights potential challenges.
... [18,19] Conflicting results have been seen [20] with some studies indicating no clear advantage over mammography on addition of tomosynthesis. [21,22] Mun et al. in their study found that addition of tomosynthesis significantly helped the assessment of lesion extent in dense breasts. [13] Haas et al. also observed a greater reduction in recall rates in dense breasts in comparison with fatty breasts. ...
Context:
Mammography in dense breasts is challenging due to lesion obscuration by tissue overlap. Does tomosynthesis offers a solution?
Aims:
To study the impact of digital breast tomosynthesis (DBT) in characterizing lesions in breasts of different mammographic densities.
Settings and design:
Prospective blinded study comparing mammography in two views with Mammography + Tomosynthesis.
Methods and material:
Tomosynthesis was performed in 199 patients who were assigned Breast imaging reporting and data system (BIRADS) categories 0, 3, 4, or 5 on two-dimensional (2D) mammogram. Mammograms were first categorized into one of 4 mammographic breast densities in accordance with the American College of Radiology (ACR). Three radiologists independently analyzed these images and assigned a BIRADS category first based on 2D mammogram alone, and then assigned a fresh BIRADS category after taking mammography and tomosynthesis into consideration. A composite gold-standard was used in the study (histopathology, ultrasound, follow-up mammogram, magnetic resonance imaging). Each lesion was categorized into 3 groups-superior categorization with DBT, no change in BIRADS, or inferior BIRADS category based on comparison with the gold-standard. The percentage of lesions in each group was calculated for different breast densities.
Results:
There were 260 lesions (ages 28-85). Overall, superior categorization was seen in 21.2% of our readings on addition of DBT to mammography. DBT was most useful in ACR Densities 3 and 4 breasts where it led to more appropriate categorization in 27 and 42% of lesions, respectively. DBT also increased diagnostic confidence in 54.5 and 63.6% of lesions in ACR Densities 3 and 4, respectively.
Conclusions:
In a diagnostic setting, the utility of tomosynthesis increases with increasing breast density. This helps in identifying the sub category of patients where DBT can actually change management.
... The image volume consists of a large number of slice images, leading to a significant increase in the amount of data and reading time compared to standard mammography. This is a major concern when considering BT as an alternative or complement to standard mammography in breast cancer screening [3][4][5][6] . ...
The large image volumes in breast tomosynthesis (BT) have led to large amounts of data and a heavy workload for breast radiologists. The number of slice images can be decreased by combining adjacent image planes (slabbing) but the decrease in depth resolution can considerably affect the detection of lesions. The aim of this work was to assess if thicker slabbing of the outer slice images (where lesions seldom are present) could be a viable alternative in order to reduce the number of slice images in BT image volumes. The suggested slabbing (an image volume with thick outer slabs and thin slices between) were evaluated in two steps. Firstly, a survey of the depth of 65 cancer lesions within the breast was performed to estimate how many lesions would be affected by outer slabs of different thicknesses. Secondly, a selection of 24 lesions was reconstructed with 2, 6 and 10 mm slab thickness to evaluate how the appearance of lesions located in the thicker slabs would be affected. The results show that few malignant breast lesions are located at a depth less than 10 mm from the surface (especially for breast thicknesses of 50 mm and above). Reconstruction of BT volumes with 6 mm slab thickness yields an image quality that is sufficient for lesion detection for a majority of the investigated cases. Together, this indicates that thicker slabbing of the outer slice images is a promising option in order to reduce the number of slice images in BT image volumes.
We present a comprehensive investigation into the organizational, social, and ethical impact of implementing digital breast tomosynthesis (DBT) as a primary test for breast cancer screening in Italy. The analyses aimed to assess the feasibility of DBT specifically for all women aged 45–74, women aged 45–49 only, or those with dense breasts only.
Questions were framed according to the European Network of Health Technology Assessment (EuNetHTA) Screening Core Model to produce evidence for the resources, equity, acceptability, and feasibility domains of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) decision framework. The study integrated evidence from the literature, the MAITA DBT trials, and Italian pilot programs. Structured interviews, surveys, and systematic reviews were conducted to gather data on organizational impact, acceptability among women, reading and acquisition times, and the technical requirements of DBT in screening.
Implementing DBT could significantly affect the screening program, primarily due to increased reading times and the need for additional human resources (radiologists and radiographers). Participation rates in DBT screening were similar, if not better, to those observed with standard digital mammography, indicating good acceptability among women. The study also highlighted the necessity for specific training for radiographers. The interviewed key persons unanimously considered feasible tailored screening strategies based on breast density or age, but they require effective communication with the target population.
An increase in radiologists’ and radiographers’ workload limits the feasibility of DBT screening. Tailored screening strategies may maximize the benefits of DBT while mitigating potential challenges.
Keratinocyte carcinomas, including basal and squamous cell carcinomas, are the most common human cancers worldwide. While 75% of all keratinocyte carcinoma (4 million annual cases in the United States) are treated with conventional excision, this surgical modality has much lower cure rates than Mohs micrographic surgery, likely due to the bread-loaf histopathologic assessment that visualizes <1% of the tissue margins. A quenched protease-activated fluorescent probe 6qcNIR, which produces a signal only in the protease-rich tumor microenvironment, was topically applied to 90 specimens ex vivo immediately following excision. “Puzzle-fit” analysis was used to correlate the fluorescent images with histology. Probe-dependent fluorescent images correlated with cancer determined by conventional histology. Point-of-care fluorescent detection of skin cancer had a clinically relevant sensitivity of 0.73 and corresponding specificity of 0.88. Importantly, clinicians were effectively trained to read fluorescent images within 15 minutes with reliability and confidence, resulting in sensitivities of 62%–78% and specificities of 92%–97%. Fluorescent imaging using 6qcNIR allows 100% tumor margin assessment by generating en face images that correlate with histology and may be used to overcome the limitations of conventional bread-loaf histology. The utility of 6qcNIR was validated in a busy real-world clinical setting, and clinicians were trained to effectively read fluorescent margins with a short guided instruction, highlighting clinical adaptability. When used in conventional excision, this approach may result in higher cure rates at a lower cost by allowing same-day reexcision when needed, reducing patient anxiety and improving compliance by expediting postsurgical specimen assessment.
Significance
A fluorescent-probe-tumor-visualization platform was developed and validated in human keratinocyte carcinoma excision specimens that may provide simple, rapid, and global assessment of margins during skin cancer excision, allowing same-day reexcision when needed.
Digital Mammography and Digital Breast Tomosynthesis.
Digital breast tomosynthesis (DBT) has been shown to be a promising imaging technique for
breast cancer detection. DBT involves acquisition of a series of images in different planes over a
limited angular range, and their subsequent reconstruction into a quasi-three-dimensional
breast volume. This reduces the effects of tissue overlap. This review aims to describe the key
features of DBT, including technique, results from recent retrospective and prospective clinical
studies, and issues with DBT as a screening tool.
Purpose:
Currently in diagnostic setting for breast cancer, FFDM and DBT are performed conjunctively. However, performing two imaging modalities may increase radiation exposure by double. Two-dimensional reconstructed images created from DBT with 2DSM, has a potential to replace conventional FFDM in concerning both radiation dosage and image quality. With increasing concerns for individual radiation exposure, studies analyzing radiation dosage in breast imaging modalities are needed. This study compared radiation dosage and image quality between DBT + 2DSM versus FFDM.
Methods and materials:
374 patients (mean age 52 years) who underwent both DBT and FFDM were retrospectively reviewed. Radiation dosage data were obtained by radiation dosage scoring and monitoring program Radimetrics (Bayer HealthCare, Whippany, NJ). Entrance dose and mean glandular doses in each breast were obtained for both modalities. To compare image quality of DBT + 2DSM and FFDM, a 5-point scoring system for lesion clarity was assessed. The parameters of radiation dosage (entrance dose, mean glandular dose) and image quality (lesion clarity scoring) were compared.
Results:
For entrance dose, DBT had lower mean dosage (14.8 mGy) compared with FFDM (21.8 mGy, p-value < 0.0001). Mean glandular doses for both breasts were lower in DBT (Left 1.74, Right 2.1) compared with FFDM (Left 2.85, Right 2.74, p-value < 0.0001). Lesion clarity score was higher in DBT with 2DSM (mean score 4.03) compared with FFDM (3.82, p-value < 0.0001).
Conclusion:
DBT showed lower radiation entrance dose and mean glandular doses to both breasts compared with FFDM. DBT + 2DSM had better image quality than FFDM, suggesting that DBT with 2DSM has potential as an alternative to FFDM.
The last 15 years has seen the advent of a variety of powerful 3D x-ray based breast imaging modalities such as digital breast omosynthesis, digital breast computed tomography, and stereo mammography.
These modalities promise to herald a new and exciting future for early detection and diagnosis of breast cancer. In this chapter, the authors review some of the recent developments in 3D x-ray based breast
imaging. They also review some of the initial work in the area of computer-aided detection and diagnosis for 3D x-ray based breast imaging. The chapter concludes by discussing future research directions in 3D computer-aided detection.
Dual energy (DE) imaging technique has been applied to many theoretical and experimental studies. The aim of the current study is to evaluate dual energy in breast tomosynthesis using commercial tomosynthesis system in terms of its potential to better visualize microcalcifications (μCs). The system uses a tungsten target X-ray tube and a selenium direct conversion detector. Low-energy (LE) images were acquired at different tube voltages (28, 30, 32 kV), while high-energy images at 49 kV. Fifteen projections, for the low- and high-energy respectively, were acquired without grid while tube scanned continuously. Log-subtraction algorithm was used in order to obtain the DE images with the weighting factor, w, derived empirically. The subtraction was applied to each pair of LE and HE slices after reconstruction. The TORMAM phantom was imaged with the different settings. Four regions-of-interest including μCs were identified in the inhomogeneous part of the phantom. The μCs in DE images were more clearly visible compared to the low-energy images. Initial results showed that DE tomosynthesis imaging is a promising modality, however more work is required.
Breast imaging plays a critical role in the detection, diagnosis, and treatment of both benign breast disease and breast cancer. Over the past two decades, there has been exponential growth in the variety of available imaging modalities. In this chapter, we review the current role of digital mammography, digital breast tomosynthesis, contrast-enhanced mammography, breast ultrasound and elastography, and magnetic resonance imaging in the primary and supplemental screening of asymptomatic women and in management of women diagnosed with breast cancer. By understanding the strengths and limitations of these technologies, providers will be able to optimize the care of women with suspected or newly diagnosed malignancies.
Digital breast tomosynthesis is quickly becoming the standard of care in breast cancer screening and diagnosis. Since its introduction to the clinical landscape in 2011, radiologists specializing in breast disease diagnosis around the country have made the decision to adopt the technology for both screening and diagnostic applications; with adoption growing substantially in present day. Users of the technology have attested to the benefits the technology affords, both in screening and the diagnostic evaluation of patients, through peer-reviewed publications and scientific presentations in recent years. This review article will describe the history of digital breast tomosynthesis and its implementation; from the early days of research, through Food and Drug Administration approval, to integration into the clinical workflow, in the setting of screening and diagnostic evaluation.
Objectives:
To compare the diagnostic accuracy and efficiency in the interpretation of digital breast tomosynthesis (DBT) images using picture archiving and communication system (PACS) and a dedicated workstation.
Methods:
A total of 97 DBT images performed for screening or diagnostic purposes were stored in both a workstation and PACS, and evaluated in combination with digital mammography by three independent radiologists retrospectively. Breast Imaging Reporting and Data System final assessments and likelihood of malignancy (%) were assigned and the interpretation time when using the workstation and PACS was recorded. Receiver operating characteristic (ROC) curve analysis, sensitivities, and specificities were compared with histopathologic examination and follow-up data as a reference standard.
Results:
Area under ROC curve values for cancer detection (0.839 vs. 0.815, P=0.6375) and sensitivity (81.8% vs. 75.8%, P=0.2188) showed no statistical significant differences between workstation and PACS. However, specificity was significantly higher when analyzing on the workstation than when using PACS (83.7% vs. 76.9%, P=0.009). When evaluating DBT images using PACS, only one case was deemed necessary to be reanalyzed using the workstation. The mean time to interpret DBT images on PACS (1.68 min/case) was significantly longer than that to interpret on the workstation (1.35 min/case) (P<0.0001).
Conclusions:
Interpretation of DBT images using PACS showed comparable diagnostic performance to a dedicated workstation, even though it required a longer reading time. Advances in Knowledge: Interpretation of DBT images using PACS showed comparable diagnostic performance to a dedicated workstation, even though it required a longer reading time.
In the last 20 years, there has been rapid evolution of the clinical research on digital breast tomosynthesis supporting its adoption in clinical breast imaging practice. Beginning with proof of principle pilot observational studies and culminating in prospective population-based screening trials and outcome reporting from clinical practice, there is a wealth of data on the DBT technology. This article catalogs the scientific and clinical evidence of DBT, highlighting some of the most important studies that have been reported to date.
The field of medical image quality has relied on the assumption that metrics of image quality for simple visual detection tasks are a reliable proxy for the more clinically realistic visual search tasks. Rank order of signal detectability across conditions often generalizes from detection to search tasks. Here, we argue that search in 3D images represents a paradigm shift in medical imaging: radiologists typically cannot exhaustively scrutinize all regions of interest with the high acuity fovea requiring detection of signals with extra-foveal areas (visual periphery) of the human retina. We hypothesize that extra-foveal processing can alter the detectability of certain types of signals in medical images with important implications for search in 3D medical images. We compare visual search of two different types of signals in 2D vs. 3D images. We show that a small microcalcification-like signal is more highly detectable than a larger mass-like signal in 2D search, but its detectability largely decreases (relative to the larger signal) in the 3D search task. Utilizing measurements of observer detectability as a function retinal eccentricity and observer eye fixations we can predict the pattern of results in the 2D and 3D search studies. Our findings: 1) suggest that observer performance findings with 2D search might not always generalize to 3D search; 2) motivate the development of a new family of model observers that take into account the inhomogeneous visual processing across the retina (foveated model observers).
Objective: The aim of this study was to evaluate the clinical performance of 3D tomosynthesis in comparison with Full Field Digital Mammography (FFDM) in the detection and diagnosis of breast lesions.
Material and methods: 132 patients underwent standard digital mammography and tomosynthesis and the likelihood of malignancy was categorized according to (ACR) BI-RADS.
Results: Tomosynthesis images had significantly increased the number of cases with BI-RAD 1 or 2 (normal/benign) to 62 (42.7%) compared to 39 (26.8%) at mammogram (p
Rationale and objectives:
The addition of digital breast tomosynthesis (DBT) to digital screening mammography (DM) has been shown to decrease recall rates and improve cancer detection rates, but there is a lack of data regarding the impact of DBT on rates of short-term follow-up. We assessed possible changes in performance measures with the introduction of DBT at our facility.
Materials and methods:
In our observational study, databases were used to compare rates of recall, short-term follow-up, biopsy, and cancer detection between women undergoing DM without (n = 10,477) and women undergoing DM with (n = 2304) the addition of DBT. Regression analysis was performed to determine associations with patient age, breast density, and availability of comparison examinations.
Results:
The addition of DBT resulted in significantly lower recall rates (16%-14%, P = .017), higher rates of biopsy (12.7%-19.1%, P < .01), and increased detection of ductal carcinoma in situ, with a difference of 2.3 cases per 1000 screens (P = .044). A 33% increase in cancer detection rates was observed with DBT, which did not reach statistical significance. Short-term follow-up of probably benign findings was 80% higher in the DBT group (odds ratio = 1.80, 95% confidence interval = 1.38-2.36, P < .001).
Conclusions:
To our knowledge, we are the first to study the impact of DBT on rates of short-term follow-up, and observed an 80% increase over the DM group. Further research is needed to determine the malignancy rate of Breast Imaging Reporting and Data System 3 lesions detected with DBT, and establish appropriate follow-up to maximize cancer detection while minimizing expense and patient anxiety.
Purpose
To assess utilization of digital breast tomosynthesis (DBT) and examine criteria for offering DBT to patients.
Methods
We created an online survey for physician members of the Society of Breast Imaging to assess their use of DBT. The questions covered availability of DBT at the participant's practice, whether DBT was used for clinical care or research, clinical decision rules guiding patient selection for DBT, costs associated with DBT, plans to obtain DBT, and breast imaging practice characteristics. Fisher's exact tests and logistic regression were used to compare DBT users and nonusers.
Results
In all, 670 members responded (response rate = 37%). Of these, 200 (30.0%) respondents reported using DBT, with 89% of these using DBT clinically. Participants were more likely to report DBT use if they worked at an academic practice (odds ratio [OR], 2.07; 95% confidence interval [CI], 1.41 to 3.03; P < .001), a practice with more than 3 breast imagers (OR, 2.36; 95% CI, 1.62 to 3.43; P < .001), or a practice with 7 or more mammography units (OR, 3.05; 95% CI, 2.11 to 4.39; P < .001). Criteria used to select patients to undergo DBT varied, with 107 (68.2%) using exam type (screening versus diagnostic), 25 (15.9%) using mammographic density, and 25 (15.9%) using breast cancer risk. Fees for DBT ranged from 250. In addition, 62.3% of nonusers planned to obtain DBT.
Conclusion
DBT is becoming more common but remains a limited resource. Clinical guidelines would assist practices in deciding whether to adopt DBT and in standardizing which patients should receive DBT.
Emerging imaging technologies, including digital breast tomosynthesis, have the potential to transform breast cancer screening. However, the rapid adoption of these new technologies outpaces the evidence of their clinical and cost-effectiveness. The authors describe the forces driving the rapid diffusion of tomosynthesis into clinical practice, comparing it with the rapid diffusion of digital mammography shortly after its introduction. They outline the potential positive and negative effects that adoption can have on imaging workflow and describe the practice management challenges when incorporating tomosynthesis. The authors also provide recommendations for collecting evidence supporting the development of policies and best practices.
Objective: To assess the impact of digital breast tomosynthesis (DBT) and magnetic resonance mammography (MRM) in enhancing the performance of digital mammography (DM) in the detection and evaluation of different breast lesions.
Patients and methods: In this retrospective study, 98 patients with 103 breast lesions were assessed by DM, DBT and MRM. Mammography images were acquired using the “combo mode", where both DM and DBT scanned in the same compression. MRM was performed by 1T open system. Each lesion was assigned a blinded category in an individual performance for each modality. The resultant BI-RADS categories were correlated with reports of the pathology specimens or outcome of 18-month follow-up.
Results: Both DBT and MRM showed equivalent sensitivity of 92%. The specificity for DBT and MRM was 80.7% and 89.7% respectively. The efficacy of DM was raised from 61% to 83.5% with DBT and 90.2% with MRM. The results of the three modalities and the final diagnosis revealed a significant correlation (p = 0.035).The association between the results of DBT and those of MRM showed statistically significant difference between DBT and MRM for diagnosing breast lesions (p = 0.001).
Conclusion: Both MRM and DBT provide better performance than classic DM. Adding either of these modalities to the classic examination enhances diagnosis and precise disease distribution.
Objective
To compare the visibility of circumscribed masses on digital breast tomosynthesis (DBT) images and 2D mammograms and determine the usefulness of DBT for differentiation between benign and malignant circumscribed masses. Methods
Seventy-one (19 malignant and 52 benign) mammographic well-circumscribed masses were included. Visibility of the masses and halo signs on DBT images were retrospectively compared with 2D mammograms. The effects of mammographic breast density on mass visibility were also evaluated. ResultsFor DBT, 83% were superior and 17% were equivalent in visibility of the masses to that of 2D, and superiority of DBT was significantly enhanced in the high breast density group compared with the low breast density group (91% vs 68%, respectively, p = 0.016). Three lesions were only detected on DBT. There was no significant difference in the superiority of DBT for lesion visibility between malignant and benign masses. The halo sign was detected in 58% lesions on DBT and in 4% on 2D (p < 0.001). Conclusion
Circumscribed masses were better visualized on DBT than on 2D mammograms, particularly in high-density breasts. The halo sign often appeared on DBT and gave a clearer mass margin. However, circumscribed masses on DBT are not assured of being benign. Key Points• Circumscribed masses were better visualized on breast tomosynthesis than on 2D mammography.• Tomosynthesis visualized circumscribed masses better than 2D for all breast density categories.• Halo signs often appeared on tomosynthesis and contributed to detect circumscribed margins.• Circumscribed masses on tomosynthesis images are not assured of being benign lesions.
Digital Breast Tomosynthesis (DBT) has the potential to replace or supplement Digital Mammography (DM). Studies have shown that it takes radiologists more time to read DBT examinations compared with DM. The slice separation of image volumes has been set to 1 mm on most systems. By using thicker slices review time could be reduced. This paper investigates the possibility of using 2 mm Average Intensity Pixel (AIP) slabs for image review. The thicker slabs were created using a method based on statistical artifact reduction and super-resolution. Six radiologists were presented with 20 sets of images containing 16 tumor masses and 8 micro-calcification clusters. They ranked 2 mm slabbed sets relative to standard 1 mm. Visibility (P = .0044) of micro-calcifications improved and there was no significant effect on mass visibility (P = .46). The results indicate that it is possible to review DBT-volumes with 2 mm slabs without compromising image quality.
There has been significant advancement in mammographic technology since the widespread deployment of screening began in the 1970s. Utilization of screening mammography has dramatically altered the clinical presentation of breast cancer. There remains, however, a subset of breast cancer (accounting for approximately 15–20 %), which is not detectable with even modern digital 2D mammography. This is generally seen in women with radiographically dense breasts in whom mammographic sensitivity for breast cancer falls to just 50 % [Carney et al., Ann Intern Med 138:168–175, 2003]. According to a recent study in the Journal of the National Cancer Institute, these women with dense breast tissue, in whom conventional 2D mammography is limited, are actually at a higher risk for developing breast cancer [Yaghjyan et al., J Natl Cancer Inst 103(15):1179–89, 2011].
Computed Tomography (CT) is the gold standard for image evaluation of lung disease, including lung cancer and cystic fibrosis. It provides detailed information of the lung anatomy and lesions, but at a relatively high cost and high dose of radiation. Chest radiography is a low dose imaging modality but it has low sensitivity. Digital chest tomosynthesis (DCT) is an imaging modality that produces 3D images by collecting x-ray projection images over a limited angle. DCT is less expensive than CT and requires about 1/10th the dose of radiation. Commercial DCT systems acquire the projection images by mechanically scanning an x-ray tube. The movement of the tube head limits acquisition speed. We recently demonstrated the feasibility of stationary digital chest tomosynthesis (s-DCT) using a carbon nanotube (CNT) x-ray source array in benchtop phantom studies. The stationary x-ray source allows for fast image acquisition. The objective of this study is to demonstrate the feasibility of s-DCT for patient imaging. We have successfully imaged 31 patients. Preliminary evaluation by board certified radiologists suggests good depiction of thoracic anatomy and pathology.
Although the receiver operating characteristic (ROC) paradigm is the accepted method for evaluation of diagnostic imaging systems, it has some serious shortcomings inasmuch as it is restricted to one observer report per image. By contrast the free-response ROC (FROC) paradigm and associated analysis method allows the observer to report multiple abnormalities within each imaging study, and uses the location of reported abnormalities to improve the measurement. Because the ROC method cannot accommodate multiple responses or use location information, its statistical power will suffer. The FROC paradigm/analysis has not enjoyed widespread acceptance because of concern about whether responses made to the same diagnostic study can be treated as independent. We propose a new jackknife FROC analysis method (JAFROC) that does not make the independence assumption. The new analysis method combines elements of FROC and the Dorfman-Berbaum-Metz (DBM) methods. To compare JAFROC to an earlier free-response analysis method (specifically the alternative free-response, or AFROC method), and to the DBM method, which uses conventional ROC scoring, we developed a model for generating simulated FROC data. The simulation model is based on an eye-movement model of how experts evaluate images. It allowed us to examine null hypothesis (NH) behavior and statistical power of the different methods. We found that AFROC analysis did not pass the NH test, being unduly conservative. Both the JAFROC method and the DBM method passed the NH test, but JAFROC had more statistical power than the DBM method. The results of this comparison suggest that future studies of diagnostic performance may enjoy improved statistical power or reduced sample size requirements through the use of the JAFROC method.
Initial results for a computerized mass lesion detection scheme for digital breast tomosynthesis (DBT) images are presented. The algorithm uses a radial gradient index feature for the initial lesion detection and for segmentation of lesion candidates. A set of features is extracted for each segmented partition. Performance of two- and three dimensional features was compared. For gradient features, the additional dimension provided no improvement in classification performance. For shape features, classification using 3D features was improved compared to the 2D equivalent features. The preliminary overall performance was 76% sensitivity at 11 false positives per exam, estimated based on DBT image data of 21 masses. A larger database will allow for further development and improvement in our computer aided detection scheme.
The purpose of the study was to design a computer-aided detection (CAD) system for breast mass detection on digital breast tomosynthesis (DBT) mammograms and to perform a preliminary evaluation of the performance of this system. Twenty-six patients were imaged with a prototype DBT system. Institutional review board approval and written informed patient consent were obtained. Use of the data set in this study was HIPAA compliant. The CAD system first screened the three-dimensional volume of the mass candidates by means of gradient-field analysis. Each mass candidate was segmented from the structured background, and its image features were extracted. A feature classifier was designed to differentiate true masses from normal tissues. The CAD system was trained and tested by using a leave-one-case-out method. The classifier calculated a mean area under the test receiver operating characteristic curve of 0.91 +/- 0.03 (standard error of mean). The CAD system achieved a sensitivity of 85%, with 2.2 false-positive objects per case. The results demonstrate the feasibility of the authors' approach to the development of a CAD system for DBT mammography.
This paper describes a high-quality, multisite telemammography system to enable "almost real-time" remote patient management while the patient remains in the clinic. One goal is to reduce the number of women who would physically need to return to the clinic for additional imaging procedures (termed "recall") to supplement "routine" imaging of screening mammography.
Mammography films from current and prior (when available) examinations are digitized at three remote sites and transmitted along with other pertinent information across low-level communication systems to the central site. Images are automatically cropped, wavelet compressed, and encrypted prior to transmission to the central site. At the central site, radiologists review and rate examinations on a high-resolution workstation that displays the images, computer-assisted detection results, and the technologist's communication. Intersite communication is provided instantly via a messaging "chat" window.
The technologists recommended additional procedures at 2.7 times the actual clinical recall rate for the same cases. Using the telemammography system during a series of "off-line" clinically simulated studies, radiologists recommended additional procedures at 1.3 times the actual clinical recall rate. Percent agreement and kappa between the study and actual clinical interpretations were 66.1% and 0.315, respectively. For every physical recall potentially avoided using the telemammography system, approximately one presumed "unnecessary" imaging procedure was recommended.
Remote patient management can reduce the number of women recalled by as much as 50% without performing an unreasonable number of presumed "unnecessary" procedures.
This paper proposes an extension of generalized linear models to the analysis of longitudinal data. We introduce a class of
estimating equations that give consistent estimates of the regression parameters and of their variance under mild assumptions
about the time dependence. The estimating equations are derived without specifying the joint distribution of a subject's observations
yet they reduce to the score equations for niultivariate Gaussian outcomes. Asymptotic theory is presented for the general
class of estimators. Specific cases in which we assume independence, m-dependence and exchangeable correlation structures from each subject are discussed. Efficiency of the pioposecl estimators
in two simple situations is considered. The approach is closely related to quasi-likelihood.
To describe and evaluate a method of tomosynthesis breast imaging with a full-field digital mammographic system.
In this tomosynthesis method, low-radiation-dose images were acquired as the x-ray source was moved in an arc above the stationary breast and digital detector. A step-and-expose method of imaging was used. Breast tomosynthesis and conventional images of two imaging phantoms and four mastectomy specimens were obtained. Three experienced readers scored the relative lesion visibility, lesion margin visibility, and confidence in the classification of six lesions.
Tomosynthesis image-reconstruction algorithms allow tomographic imaging of the entire breast from a single arc of the x-ray source and at a radiation dose comparable with that in single-view mammography. Except for images of a large mass in a fatty breast, the tomosynthesis images were superior to the conventional images.
Digital mammographic systems make breast tomosynthesis possible. Tomosynthesis may improve the specificity of mammography with improved lesion margin visibility and may improve early breast cancer detection, especially in women with radiographically dense breasts.
To describe measures of mammography performance in a geographically defined population and evaluate the interpreter's use of the Breast Imaging Reporting and Data System (BI-RADS).
Mammographic data from 47,651 screening and 6,152 diagnostic examinations from November 1, 1996, to October 31, 1997, were linked to 1,572 pathologic results. Mammographic outcomes were based on BI-RADS assessments and recommendations reported by the interpreting radiologist. The consistency of BI-RADS recommendations was evaluated.
Screening mammography had a sensitivity of 72.4% (95% CI: 66.4%, 78.4%), specificity of 97.3% (95% CI: 97.25%, 97.4%), and positive predictive value of 10.6% (95% CI: 9.1%, 12.2%). Diagnostic mammography had higher sensitivity, 78.1% (95% CI: 71.9%, 84.3%); lower specificity, 89.3% (95% CI: 88.5%, 90.1%); and better positive predictive value, 17.1% (95% CI: 14.5%, 19.8%). The cancer detection rate with screening mammography was 3.3 per 1,000 women, with a biopsy yield of 22.4%, whereas the interval cancer rate was 1. 2 per 1,000. Nearly 80% of screening-detected invasive malignancies were node negative. The recall rate for screening mammography was 8. 3%. Ultrasonography was used in 3.5% of screening and 17.5% of diagnostic examinations. BI-RADS recommendations were generally consistent, except for probably benign assessments.
The sensitivity of screening mammography in this population-based sample is lower than expected, although other performance indicators are commendable. BI-RADS "probably benign" assessments are commonly misused.
The purpose of this study was to comparatively evaluate digital planar mammography and both linear and nonlinear tomosynthetic reconstruction methods.
A "disk" (ie, target) identification study was conducted to compare planar and reconstruction methods. Projective data using a composite phantom with circular disks were acquired in both planar and tomographic modes by using a full-field, digital mammographic system. Two-dimensional projections were reconstructed with both linear (ie, backprojection) and nonlinear (ie, maximization and minimization) tuned-aperture computed tomographic (TACT) methods to produce three-dimensional data sets. Four board-certified radiologists and one 4th-year radiology resident participated as observers. All images were compared by these observers in terms of the number of disks identified.
Significant differences (P < .05, Bonferroni adjusted) were observed between all reconstruction and planar methods. No significant difference, however, was observed between the planar methods, and only a marginally significant difference (P < .054, Bonferroni adjusted) was observed between TACT-backprojection and TACT-minimization.
A combination of linear and nonlinear reconstruction schemes may have potential implications in terms of enhancing image visualization to provide radiologists with valuable diagnostic information.
Breast tomosynthesis is a 3-dimensional (3-D) imaging technology that involves acquiring images of a stationary compressed breast at multiple angles during a short scan. The individual images are then reconstructed into a series of thin high-resolution slices that displayed individually or in a dynamic ciné mode. Tomosynthesis can reduce or eliminate the tissue overlap effect. While holding the breast stationary, images are acquired at a nsumber of different x-ray source angles. Objects at different heights in the breast project differently for each angle. The final step in the tomosynthesis procedure is reconstructing the data to generate images that enhance objects from a given height by appropriate shifting of the projections relative to one another. There are 3 specific areas in tomosynthesis system requirements that warrant a closer review: detector efficiency and dose, field of view, and equipment geometry. The breast is compressed in a standard way. While holding the breast stationary, the x-ray tube is rotated over a limited angular range. A series of low dose exposures are made every few degrees, creating a series of digital images. Typically, the tuben is rotated about +/-15 degrees, and 11 exposures are made every 3 degrees during a total scan of a few seconds. The individual images are projections through the breast at different angles and these arewhat are reconstructed into slices. There are 2 basic tomosynthesis system designs that diiffer in the motion of the detector during acquisition. One method moves the detector in concert with the x-ray tube so as to maintain the shadow of the breast on the detector. An altemate method is to keep the detector stationary relative to the breast platform. The tomosynthesis reconstruction process consists of computing high-resolution images whose planes are parallel to the breast support plates. Typically, these images are reconstructed with slice separation of 1 mm; thus, a 5 cm compressed breast tomosynthesis study will have 50 reconstructed slices. The reconstructed tomosynthesis slices can be displayed similarly to computed tomography (CT) reconstructed slices. Tomosynthesis could resolve many of the tissue overlap reading problems that are a major source of the need for recalls and additional imaging in 2-D mammography exams.
Digital breast tomosynthesis (DBT) has recently emerged as a new and promising three-dimensional modality in breast imaging. In DBT, the breast volume is reconstructed from 11 projection images, taken at source angles equally spaced over an arc of 50 degrees. Reconstruction algorithms for this modality are not fully optimized yet. Because computerized lesion detection in the reconstructed breast volume will be affected by the reconstruction technique, we are developing a novel mass detection algorithm that operates instead on the set of raw projection images. Mass detection is done in three stages. First, lesion candidates are obtained for each projection image separately, using a mass detection algorithm that was initially developed for screen-film mammography. Second, the locations of a lesion candidate are backprojected into the breast volume. In this feature volume, voxel intensities are a combined measure of detection frequency (e.g., the number of projections in which a given lesion candidate was detected), and a measure of the angular range over which a given lesion was detected. Third, features are extracted after reprojecting the three-dimensional (3-D) locations of lesion candidates into projection images. Features are combined using linear discriminant analysis. The database used to test the algorithm consisted of 21 mass cases (13 malignant, 8 benign) and 15 cases without mass lesions. Based on this database, the algorithm yielded a sensitivity of 90% at 1.5 false positives per breast volume. Algorithm performance is positively biased because this dataset was used for development, training, and testing, and because the number of algorithm parameters was approximately the same as the number.of patient cases. Our results indicate that computerized mass detection in the sequence of projection images for DBT may be effective despite the higher noise level in those images.
The free-response paradigm is being increasingly used in the assessment of medical imaging systems. The currently implemented method of analyzing the data, namely jackknife free-response (JAFROC) analysis, has some validation and applicability limitations. The purpose of this work is to address these limitations.
The general principles of modality evaluation and methodology validation are reviewed. A model for simulating free-response data was used to test the statistical validity of several methods of analyzing the data. The methods differed only in the choice of the figure of merit used to quantify performance. Statistical validity was judged by investigating the behaviors of the methods under null hypothesis conditions of no difference between modalities.
The validity of the different methods of analyzing the data was found to be dependent on the choice of figure of merit. A figure of merit is identified that accommodates abnormal images with multiple (one or more) lesions, detections of which could have different clinical significances (weights). This figure of merit is shown to be statistically valid. An extension of the analysis to single reader interpretations of images from different modalities is also shown to be statistically valid.
With the validated enhancements, JAFROC is expected to be of greater utility to users of the free-response method. The extension to single-reader interpretations should be of particular value to developers of image processing algorithms, including developers of computer-aided diagnosis algorithms.
Contrast-enhanced digital mammography and digital breast tomosynthesis are two imaging techniques that attempt to increase malignant breast lesion conspicuity. The combination of these into a single technique, contrast-enhanced digital breast tomosynthesis (CE-DBT), could potentially integrate the strengths of both. The objectives of this study were to assess the clinical feasibility of CE-DBT as an adjunct to digital mammography, and to correlate lesion enhancement characteristics and morphology obtained with CE-DBT to digital mammography, ultrasound, and magnetic resonance (MR).
CE-DBT (GE Senographe 2000D; Milwaukee, WI) was performed as a pilot study in an ongoing National Cancer Institute-funded grant (P01-CA85484) studying multimodality breast imaging. Thirteen patients with ACR BI-RADS category 4 or 5 breast lesions underwent imaging with digital mammography, ultrasound, MR, and CE-DBT. CE-DBT was performed at 49 kVp with a rhodium target and a 0.27-mm copper (Alfa Aesar, Ward Hill, MA) filter. Preinjection and postinjection DBT image sets were acquired in the medial lateral oblique projection with slight compression. Each image set consists of nine images acquired over a 50-degree arc and was obtained with a mean glandular x-ray dose comparable to two conventional mammographic views. Between the precontrast and postcontrast DBT image sets, a single bolus of iodinated contrast agent (1 ml/kg at 2 ml/s, Omnipaque-300; Amersham Health Inc., Princeton, NJ) was administered. Images were reconstructed using filtered-backprojection in 1-mm increments and transmitted to a clinical PACS workstation.
Initial experience suggests that CE-DBT provides morphologic and vascular characteristics of breast lesions qualitatively concordant with that of digital mammography and MR.
As an adjunct to digital mammography, CE-DBT may be a potential alternative tool for breast lesion morphologic and vascular characterization.
This article reviews the central issues that arise in the assessment of diagnostic imaging and computer-assist modalities. The paradigm of the receiver operating characteristic (ROC) curve--the dependence of the true-positive fraction versus the false-positive fraction as a function of the level of aggressiveness of the reader/radiologist toward a positive call--is essential to this field because diagnostic imaging systems are used in multiple settings, including controlled laboratory studies in which the prevalence of disease is different from that encountered in a study in the field. The basic equation of statistical decision theory is used to display how readers can vary their level of aggressiveness according to this diagnostic context. Most studies of diagnostic modalities in the last 15 years have demonstrated not only a range of levels of reader aggressiveness, but also a range of level of reader performance. These characteristics require a multivariate approach to ROC analysis that accounts for both the variation of case difficulty and the variation of reader skill in a study. The resulting paradigm is called the multiple-reader, multiple-case ROC paradigm. Highlights of historic as well as contemporary work in this field are reviewed. Many practical issues related to study design and resulting statistical power are included, together with recent developments and availability of analytical software.
The purpose of our study was to compare the image quality of tomosynthesis with that of conventional mammography and to estimate the recall rate of screening when tomosynthesis is used in addition to mammography.
Women with an abnormal screening mammography were recruited sequentially. Consenting women underwent tomosynthesis of the affected breast corresponding to the views obtained with diagnostic mammography. The study radiologist compared the image quality, including lesion conspicuity and feature analysis, of tomosynthesis with diagnostic film-screen mammography and assessed the need for recall when tomosynthesis was added to digital screening mammography. Screening recalls were considered unnecessary when tomosynthesis did not show a corresponding abnormality or allowed definitely benign lesion characterization. Fisher's exact test was used to determine the association of equivalence and recall status with mammographic finding type.
There were 99 digital screening recalls in 98 women. The image quality of tomosynthesis was equivalent (n = 51) or superior (n = 37) to diagnostic mammography in 89% (88/99). Finding type was significantly (p < 0.001) associated with equivalence. Approximately half--52/99 (52%)--of the findings would not have been recalled when digital screening mammography was supplemented with tomosynthesis. When adjusting for confounding conditions, the recall reduction was 40% (37/92). The likelihood of recall was also dependent on finding type (p = 0.004).
Subjectively, tomosynthesis has comparable or superior image quality to that of film-screen mammography in the diagnostic setting, and it has the potential to decrease the recall rate when used adjunctively with digital screening mammography.