Assessment of the uterine dose in digital mammography and digital breast tomosynthesis

IntroductionDigital Mammography (DM-2D) and more recently Digital Breast Tomosynthesis (DBT), are two of the most effective imaging modalities for breast cancer detection, often used in screening programmes. It may happen that exams using these two imaging modalities are inadvertently performed to pregnant women. The objective of this study is to assess the dose in the uterus due to DM-2D and DBT exams, according to two main irradiation scenarios: in the 1st scenario the exposure parameters were pre-selected directly by the imaging system, while in the 2nd scenario, the maximum exposure parameters were chosen.MethodsThe mammography equipment used was a Siemens Mammomat Inspiration. A physical anthropomorphic phantom, PMMA plates (simulating a breast thickness of 6 cm) and thermoluminescent dosimeters (TLDs) were used to measure entrance air kerma values on the phantom's breast and abdomen in order to successively estimate the mean glandular dose (MGD) and the dose in the uterus. For the two irradiation scenarios chosen, two-breast imaging modalities were selected: 1) DBT in Cranio-Caudal (CC) view (with 28 kV and 160 mAs as exposure parameters), 2) DBT and DM in Medio Lateral-Oblique (MLO) and CC views (with 34 kV and 250 mAs as exposure parameters).ResultsIn the 1st scenario, the TLD measurements did not detect significant dose values in the abdomen whereas the MGD estimated using the D.R. Dance model was in close agreement with data available in the literature. In the 2nd scenario, there was no significant difference in MGD estimation between the different views, whereas the air kerma values in the abdomen (in DBT mode, CC and MLO) were 0.049 mGy and 0.004 mGy respectively. In CC DM-2D mode the abdomen air kerma value was 0.026 mGy, with no significant detected value in MLO view.ConclusionsFor the dose in the uterus, the obtained values seem to indicate that DM-2D and DBT examinations inadvertently performed during pregnancy do not pose a significant radiological risk, even considering the case of overexposure in both breasts.Implications for practiceThe accurate knowledge of the doses in DM-2D and DBT will contribute to raise the awareness among medical practitioners involved in breast imaging empowering them to provide accurate information about dose levels in the uterus, improving their radiation risk communication skills and consequently helping to reduce the anxiety of pregnant women undergoing this type of examinations.     

Breast cancer detection: Comparison of digital mammography and digital breast tomosynthesis across non-dense and dense breasts

IntroductionBreast 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).MethodsEleven 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.ResultsDBT 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.ConclusionDiagnostic 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 practiceThe 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.     

Breast tomosynthesis and digital mammography: a comparison of diagnostic accuracy

Objective

Our aim was to compare the ability of radiologists to detect breast cancers using one-view breast tomosynthesis (BT) and two-view digital mammography (DM) in an enriched population of diseased patients and benign and/or healthy patients.

Methods

All participants gave informed consent. The BT and DM examinations were performed with about the same average glandular dose to the breast. The study population comprised patients with subtle signs of malignancy seen on DM and/or ultrasonography. Ground truth was established by pathology, needle biopsy and/or by 1-year follow-up by mammography, which retrospectively resulted in 89 diseased breasts (1 breast per patient) with 95 malignant lesions and 96 healthy or benign breasts. Two experienced radiologists, who were not participants in the study, determined the locations of the malignant lesions. Five radiologists, experienced in mammography, interpreted the cases independently in a free-response study. The data were analysed by the receiver operating characteristic (ROC) and jackknife alternative free-response ROC (JAFROC) methods, regarding both readers and cases as random effects.

Results

The diagnostic accuracy of BT was significantly better than that of DM (JAFROC: p=0.0031, ROC: p=0.0415). The average sensitivity of BT was higher than that of DM (∼90% vs ∼79%; 95% confidence interval of difference: 0.036, 0.108) while the average false-positive fraction was not significantly different (95% confidence interval of difference: −0.117, 0.010).

Conclusion

The diagnostic accuracy of BT was superior to DM in an enriched population.About 1 in 8–10 females develop breast cancer during their lifetime [1,2]. Screening mammography plays a key role in the detection of breast cancer at an early stage. Based on incidence of interval cancers it has been suggested that a radiologist reading screen-film mammograms might miss 16–30% of cancers detectable on the mammograms [3]. Mammography cancer detection varies widely: estimates of sensitivity have been reported from 68% (or as low as 48% for extremely dense breasts) to 88%, with specificities ranging from 82% to 98%. These results suggest that there is considerable room for improvement in mammography [4,5]. Digital mammography (DM) was expected to improve the performance of breast cancer detection compared with screen-film mammography (SFM). In most clinical trials the overall sensitivity has been higher for DM, but, since the specificities have also been lower, only a few studies have been statistically significant in favour of DM [5]. In a subset of females under 50 years of age in the Digital Mammographic Imaging Screening Trial study, there was a significantly improved diagnostic accuracy in DM compared with SFM [5].Because a mammogram is a two-dimensional (2D) projection of the breast onto the detector plane, overprojected healthy tissue (anatomical noise) can hamper breast cancer detectability. Anatomical noise is known to have a greater impact than quantum noise on the detection of certain breast cancers (e.g. masses) [6,7]. Two views—mediolateral oblique (MLO) and craniocaudal (CC)—can partially compensate for the overlapping anatomical noise, but this depends on the radiologist''s ability to mentally fuse the two images.Breast tomosynthesis (BT) collects 2D projection views over a limited angular range, which allows reconstruction of thin slices of the breast volume. Reduced anatomical noise from superimposed tissues is expected to improve breast cancer detection compared with DM. In CT where hundreds of projection images are acquired covering 360°, the anatomical noise can be reduced to a larger degree, but it is difficult to image the entire breast volume using CT, particularly close to the chest wall. Moreover, the average glandular dose is higher with CT, as is imaging time and the cost of the device. While there is ongoing research that may solve these issues [8-10], BT has a number of potential advantages and there are currently commercialised units.Previous studies of observer performance of BT compared with DM have shown contradictory results, varying from a statistically significant advantage for BT [11-13] to no clear advantage for BT [14-18]. Non-blinded pilot studies have been performed at our institution that suggest improved sensitivity of BT over DM [19,20].The aim of the current study was to compare the diagnostic accuracy of one-view BT with conventional two-view DM using an enriched population.     

不典型乳腺癌全数字化乳腺摄影X线表现规律探讨

目的 探讨不典型乳腺癌全数字化(FFDM)乳腺x线摄影表现规律.方法 从2003年4月至2007年7月对门诊及体检者中影像表现不典型的134例乳腺癌或癌前病变进行分析,探讨其FFDM影像表现规律.全部病例采用GE平板2000D全数字化乳腺摄影机检查,体位常规采用头尾位(CC位)、内外斜位(MLO位),必要时加摄侧位及局部点片.对临床未触及包块的乳腺癌均行术前定位.结果 (1)影像表现为边界光整的肿块以浸润性导管癌(22/106,20.8%)、黏液腺癌(8/10)及髓样癌(5/6)最多;边界光整的肿块表现随年龄的增加而增多,30～40岁年龄段占其病例总数的13.3%(4/30),81 和90岁的2例均为此类型;边界光整的肿块表现随病变局部腺体致密程度减少而增多,依次分别占各自病例总数的14.0%(12/86)、34.5%(10/29)、84.2%(16/19).(2)粗乱条索影、结构紊乱、结构紊乱伴条索影及伴片状高密度主要见于浸润性导管癌(65例),并主要见于30～40岁(22例)及41-50岁(34例)两个年龄段和病变局部为致密型的腺体组织(55例),其中粗乱条索影最多见于30～40岁,占其病例总数的33.3%(10/30).(3)全乳房密度增高伴皮下水肿及类肿块影主要见于浸润性导管癌(均为7/8)及41～50岁(5/8)年龄段;全乳房密度增高伴皮下水肿(8例)及未见异常表现(4例)仅见于致密型腺体.结论 不典型乳腺癌FFDM影像表现类型与乳腺癌的病理类型、患者的年龄及病变区腺体的致密度有关.     

Performance comparison of single-view digital breast tomosynthesis plus single-view digital mammography with two-view digital mammography

Objective

To determine the performance of combined single-view mediolateral oblique (MLO) digital breast tomosynthesis (DBT) plus single-view cranio-caudal (CC) mammography (MX) compared with that of standard two-view digital mammography.

Methods

A multi-reader multi-case (MRMC) receiver-operating characteristic (ROC) study was conducted, involving six breast radiologists. Two hundred fifty patients underwent bilateral MX and DBT imaging. MX and DBT images with the adjunct of the CC-MX view from 469 breasts were evaluated and rated independently by six readers. Differences in mean areas under the ROC curves (AUCs), mean sensitivity and mean specificity were analysed by analysis of variance (ANOVA) to assess clinical performance.

Results

The combined technique was found to be non-inferior to standard two-view mammography (MX_(CC+MLO)) in mean AUC (difference: +0.021;95 % LCL = ?0.011), but was not statistically significant for superiority (P?=?0.197). The combined technique had equivalent sensitivity to standard mammography (76.2 % vs. 72.8 %, P?=?0.269) and equivalent specificity (84.9 % vs. 83.0 %, P?=?0.130). Specificity for benign lesions was significantly higher with the combination of techniques versus mammography (45.6 % vs. 36.8 %, P?=?0.002).

Conclusion

In this enriched study population, the combination of single-view MLO tomosynthesis plus single-view CC mammography was non-inferior to that of standard two-view digital mammography in terms of ROC curve area, sensitivity and specificity.

Key Points

? Breast tomosynthesis (DBT) has emerged as a valuable adjunct to mammography (MX). ? Combination DBT/MX demonstrated non-inferior clinical performance to standard two-view MX. ? Combination DBT/MX was superior to two-view MX in recognising benign lesions. ? Combination DBT/MX reduced variability compared with two-view MX.     

Tomosynthesis and contrast-enhanced digital mammography: recent advances in digital mammography

Digital mammography is more and more replacing conventional mammography. Initial concerns about an inferior image quality of digital mammography have been largely overcome and recent studies even show digital mammography to be superior in women with dense breasts, while at the same time reducing radiation exposure. Nevertheless, an important limitation of digital mammography remains: namely, the fact that summation may obscure lesions in dense breast tissue. However, digital mammography offers the option of so-called advanced applications, and two of these, contrast-enhanced mammography and tomosynthesis, are promising candidates for improving the detection of breast lesions otherwise obscured by the summation of dense tissue. Two techniques of contrast-enhanced mammography are available: temporal subtraction of images acquired before and after contrast administration and the so-called dual-energy technique, which means that pairs of low/high-energy images acquired after contrast administration are subtracted. Tomosynthesis on the other hand provides three-dimensional information on the breast. The images are acquired with different angulations of the X-ray tube while the object or detector is static. Various reconstruction algorithms can then be applied to the set of typically nine to 28 source images to reconstruct 1-mm slices with a reduced risk of obscuring pathology. Combinations of both advanced applications have only been investigated in individual experimental studies; more advanced software algorithms and CAD systems are still in their infancy and have only undergone preliminary clinical evaluation.     

乳腺数字化断层摄影分析乳腺实质结构评估罹患乳腺癌风险:与乳腺数字化摄影比较

目的乳腺密度百分比(PD)是已被确认的罹患乳腺癌的风险因子,本研究目的是在筛查人群中评估数字化乳腺断层摄影(DBT)与数字化乳腺摄影显示的乳腺实质结构特征与PD的相关性。材料与方法本研究经专业委员会核准,受试者均签署书面知情同意书。回顾性分析2007年7月—2008年3月进行的一项经专业委员会批准的DBT筛查     

The added benefit of digital breast tomosynthesis in second breast cancer detection among treated breast cancer patients

Objectives

We aimed to compare the recall rate (RR) and the cancer detection rate (CDR) of combined full field digital mammography and digital breast tomosynthesis (FFDM?+?DBT) to those of full field digital mammography (FFDM) alone in breast cancer survivors.

Tumour characteristics and survival in patients with invasive interval breast cancer classified according to mammographic findings at the latest screening: a comparison of true interval and missed interval cancers

The aim of this study was to investigate whether different mammographic categories of interval cancer classified according to findings at the latest screening are associated with different distributions of prognostic factors or with different survival rates. The series consisted of all patients with invasive interval cancer detected from May 1978 to August 1995 (n = 544). The tumours were evaluated with regard to age, radiological category, interval between the latest screen and diagnosis and tumour characteristics at the time of diagnosis. We investigated possible relationships between the survival rate of patients with interval cancer and the interval between the latest screen and diagnosis, tumour characteristics and radiological category of the interval tumours. The study focused on comparison of patients with true interval and missed interval cancer. Women with mammographically occult tumours were younger than those in the other radiological categories. Comparisons of true interval cancers with overlooked or misinterpreted tumours showed equal distributions of age, tumour size, TNM stage and lymph node status. The overlooked or misinterpreted tumours showed significantly higher proportions of grade-I tumours (22 vs 11 %), tumours with low S-phase fraction (SPF; 44 vs 24 %) and oestrogen receptor (ER) positive tumours (72 vs 57 %). However, analyses of survival rates disclosed no clear differences between the two radiological categories. Radiological category and interval between the latest screen and diagnosis were not genuine predictors of the prognosis in patients with invasive interval breast cancer. No certain prognostic difference existed between true interval cancers and overlooked or misinterpreted interval breast cancers, despite higher proportions of grade-I tumours, ER positive tumours and tumours with low SPF in the latter group. Received: 17 December 1997; Revision received: 6 May 1998; Accepted: 27 May 1998     

Performance of computer-aided detection applied to full-field digital mammography in detection of breast cancers

Objective

The aim of this retrospective study was to evaluate performance of computer-aided detection (CAD) with full-field digital mammography (FFDM) in detection of breast cancers.

Materials and Methods

CAD was retrospectively applied to standard mammographic views of 127 cases with biopsy proven breast cancers detected with FFDM (Senographe 2000, GE Medical Systems). CAD sensitivity was assessed in total group of 127 cases and for subgroups based on breast density, mammographic lesion type, mammographic lesion size, histopathology and mode of presentation.

Results

Overall CAD sensitivity was 91% (115 of 127 cases). There were no statistical differences (p > 0.1) in CAD detection of cancers in dense breasts 90% (53/59) versus non-dense breasts 91% (62/68). There was statistical difference (p < 0.05) in CAD detection of cancers that appeared mammographically as microcalcifications only versus other mammographic manifestations. CAD detected 100% (44/44) of cancers manifesting as microcalcifications, 89% (47/53) as no-calcified masses or asymmetries, 88% (14/16) as masses with associated calcifications, and 71% (10/14) as architectural distortions. CAD sensitivity for cancers 1-10 mm was 84% (38/45); 11-20 mm 93% (55/59); and >20 mm 97% (22/23).

Conclusion

CAD applied to FFDM showed 100% sensitivity in identifying cancers manifesting as microcalcifications only and high sensitivity 86% (71/83) for other mammographic appearances of cancer. Sensitivity is influenced by lesion size. CAD in FFDM is an adjunct helping radiologist in early detection of breast cancers.     

Evaluation of tomosynthesis elastography in a breast-mimicking phantom

Objective

To evaluate whether measurement of strain under static compression in tomosynthesis of a breast-mimicking phantom can be used to distinguish tumor-simulating lesions of different elasticities and to compare the results to values predicted by rheometric analysis as well as results of ultrasound elastography.

Materials and methods

We prepared three soft breast-mimicking phantoms containing simulated tumors of different elasticities. The phantoms were imaged using a wide angle tomosynthesis system with increasing compression settings ranging from 0 N to 105 N in steps of 15 N. Strain of the inclusions was measured in two planes using a commercially available mammography workstation. The elasticity of the phantom matrix and inclusion material was determined by rheometric analysis. Ultrasound elastography of the inclusions was performed using two different ultrasound elastography algorithms.

Results

Strain at maximal compression was 24.4%/24.5% in plane 1/plane 2, respectively, for the soft inclusion, 19.6%/16.9% for the intermediate inclusion, and 6.0%/10.2% for the firm inclusion. The strain ratios predicted by rheometrical testing were 0.41, 0.83 and 1.26 for the soft, intermediate, and firm inclusions, respectively. The strain ratios obtained for the soft, intermediate, and firm inclusions were 0.72 ± 0.13, 1.02 ± 0.21 and 2.67 ± 1.70, respectively for tomosynthesis elastography, 0.91, 1.64 and 2.07, respectively, for ultrasound tissue strain imaging, and 0.97, 2.06 and 2.37, respectively, for ultrasound real-time elastography.

Conclusions

Differentiation of tumor-simulating inclusions by elasticity in a breast mimicking phantom may be possible by measuring strain in tomosynthesis. This method may be useful for assessing elasticity of breast lesions tomosynthesis of the breast.     

Diagnostic accuracy of contrast-enhanced digital mammography in breast cancer detection in comparison to tomosynthesis,synthetic 2D mammography and tomosynthesis combined with ultrasound in women with dense breast

Objective:To assess the diagnostic efficacy of contrast-enhanced digital mammography (CEDM) in breast cancer detection in comparison to synthetic two-dimensional mammography (s2D MG), digital breast tomosynthesis (DBT) alone and DBT supplemented with ultrasound examination in females with dense breast with histopathology as the gold-standard.Methods:It was a prospective study, where consecutive females presenting to symptomatic breast clinic between April 2019 and June 2020 were evaluated with DBT. Females who were found to have heterogeneously dense (ACR type C) or extremely dense (ACR type D) breast composition detected on s2D MG were further evaluated with high-resolution breast ultrasound and thereafter with CEDM, but before the core biopsy or surgical excision, were included in the study. s2D MG was derived from post-processing reconstruction of DBT data set. Females with pregnancy, renal insufficiency or prior allergic reaction to iodinated contrast agent were excluded from the study. Image interpretation was done by two experienced breast radiologists and both were blinded to histological diagnosis.Results:This study included 166 breast lesions in130 patients with mean age of 45 ± 12 years (age range 24–72 years). There were 87 (52.4%) malignant and 79 (47.6%) benign lesions. The sensitivity of CEDM was 96.5%, significantly higher than synthetic 2D MG (75.6%, p < 0.0001), DBT alone (82.8%, p < 0.0001) and DBT + ultrasound (88.5%, p = 0.0057); specificity of CEDM was 81%, significantly higher than s2D MG (63.3%, p = 0.0002) and comparable to DBT alone (84.4%, p = 0.3586) and DBT + ultrasound (79.7%, p = 0.4135). In receiver operating characteristic curve analysis, the area under the curve was of 0.896 for CEDM, 0.841 for DBT + ultrasound, 0.769 for DBT alone and 0.729 for s2D MG.Conclusion:CEDM is an accurate diagnostic technique for cancer detection in dense breast. CEDM allowed a significantly higher number of breast cancer detection than the s2D MG, DBT alone and DBT supplemented with ultrasonography in females with dense breast.Advances in knowledge:CEDM is a promising novel technology with higher sensitivity and negative predictive value for breast cancer detection in females with dense breast in comparison to DBT alone or DBT supplemented with ultrasound.     

Predictive value of mammography in early detection of breast cancer: Analysis of histological findings in breast biopsies indicatedonly by mammography

From 1985 to 1989 breast biopsies were performed in 1835 patients with suspicious mammographic findings. Inasive cancers were diagnosed in 274 patients in-situ cancers in 186. The predictive value of mammography (0.33) was correlated with the age of patient, and compared with data in the literature. The prevalence of benign and malignant lesions was correlated with the mammographic features. We suggest that the predictive value of mammography, and the ration of noninvasive to invasive cancers detected would be optimal criteria for quality control of Offprint requests to: I.Schreer     

早期乳腺癌X线征象421例分析

目的提高对早期乳腺癌X线征象的认识。方法回顾性分析421例经病理证实的早期乳腺癌的X线特征。结果421例病例中,非浸润性癌87例(20.6%),早期浸润性癌97例(23.0%),早期浸润性特殊型癌52例(12.4%),浸润性非特殊型癌(肿块直径≤1 cm)185例(44.0%)。乳腺X线检查显示89%的非浸润性癌和70%的早期浸润性癌灶可见钙化,而肿块在2组的发现率仅分别为18.0%和43.0%。结论乳腺X线片中微小钙化灶对早期乳腺癌的诊断具有重要价值。如果患者有乳头溢液,建议进一步进行乳腺导管造影检查。     

数字化乳腺摄影与普通钼靶摄影在小乳癌诊断中的对比分析

目的：探讨数字化乳腺摄影在小乳癌诊断中的优越性。方法：经手术病理证实的小乳癌57例，采用数字化乳腺摄影及普通钼靶摄影方法。结果：数字化乳腺摄影诊断51例，其敏感性、特异性、准确性分别为89．4％、95．O％、90.9％；普通钼靶摄影术前诊断46例，其敏感性、特异性、准确性分别为80．7％、85．O％、81．8％。结论：在小乳癌诊断中。数字化乳腺摄影在敏感性、特异性、准确性方面均优于普通钼靶摄影。     

MR mammography in the pre-operative staging of breast cancer in patients with dense breast tissue: comparison with mammography and ultrasound

The aim of this study was to determine whether pre-operative MR mammography could predict the extent of breast cancer in patients with dense breasts or whether dense parenchyma will lead to false-positive or inconclusive examinations. Sixty-seven patients with dense breasts with a malignant breast tumor planned for conservative surgery were reviewed. Detection rates of mammography, ultrasound, and MR mammography were studied, and the diameters of the lesions were measured and compared with pathological examination. Pathology revealed breast cancer in 65 patients. Sensitivity for detection of index lesions was 83% for mammography, 70.8% for ultrasound, and 98% for MR mammography. Mammography underestimated tumor extent in 37%, ultrasound in 40%, and MR in 12.5%. Of the 20 patients (31%) with multifocal or multicentric carcinoma, mammography detected the lesions in 35%, ultrasound in 30%, and MR in 100%, with a false-positive rate of 12.5, 14, and 23%. The MR mammography is more accurate in assessing tumor extent and multifocality in patients with dense breasts, but benign changes may lead to false-positive examinations.