Comparison between two-dimensional synthetic mammography reconstructed from digital breast tomosynthesis and full-field digital mammography for the detection of T1 breast cancer

Objective

To evaluate the interpretative performance of two-dimensional (2D) synthetic mammography (SM) reconstructed from digital breast tomosynthesis (DBT) in the detection of T1-stage invasive breast cancers, compared to 2D full-field digital mammography (FFDM).

Methods

This retrospective study enrolled 214 patients. For each patient, FFDM and DBT were performed between January and June 2013, and SM was reconstructed from DBT data. Three radiologists interpreted images and recorded visibility scores and morphologies of cancers. Diagnostic performances of SM and FFDM were compared. Percentages of detected cancers and visibility scores were compared for tumour size, and presence of calcifications for each observer.

Results

Observer sensitivity showed no difference for detection with SM and FFDM (P?>?0.05). One observer showed a higher specificity (P?=?0.02) and higher positive predictive value with SM (95 % CI 0.6–16.4), but the differences in the corresponding values between SM and FFDM for the other observers were not statistically significant. In subgroup analyses according to tumour size and presence of calcifications, percentages of detected cancers and visibility scores were not significantly different.

Conclusions

Diagnostic performances of SM and FFDM are comparable for detecting T1-stage breast cancers. Therefore, our results indicate that SM may eliminate the need for additional FFDM during DBT-based imaging.

Key Points

? DBT plus FFDM increases radiation dose compared to FFDM alone.? Detecting T1-stage cancers with only SM is comparable to detection with FFDM.? Two-dimensional SM may replace dose-requiring FFDM in DBT-based imaging.

     

DBT联合FFDM、FFDM对乳腺疾病诊断效能比较

浸润性导管癌(invasive ductal carcinoma,IDC)为最常见的乳腺癌之一,浸润性生长,具有明显转移倾向.与乳腺超声、乳腺CT及MR相比,乳腺X线摄影在对乳腺内病灶的钙化数量、形态、大小及密度的显示方面具有明显优势;数字化乳腺摄影的出现使乳腺癌的早期检出率大大提高[1].而一些乳腺疾病诸如腺病、炎症等在X线摄影上常与恶性病变难以分辨.     

全视野数字乳腺摄影结合乳腺数字体层合成摄影的辐射剂量与压迫厚度及乳房密度的相关性研究

目的 对比分析乳腺数字体层摄影及全数字乳腺摄影（DBT/FFDM）模式平均腺体剂量（AGD）与乳房密度、压迫厚度的关系,探讨不同类型（厚度和密度）乳房在具体情况下摄影方式的优化选择与应用。方法 回顾性分析229例乳房Combo （DBT+FFDM）临床资料,分别收集记录双乳正位（CC）及内外斜位（MLO）压迫厚度、AGD、kVp和乳房量化密度（Q_abd）类型,分析DBT/FFDM模式下压迫厚度、密度与AGD之间的关系。结果 DBT/FFDM模式AGD与压迫厚度（CC位：r=0.55、0.53,P<0.001;MLO位：r=0.62、0.48,P<0.001）、乳房密度（CC位：r=0.36、0.39,P<0.001;MLO位：r=0.16、0.30,P<0.001）正相关;DBT模式AGD组间差异小,FFDM模式AGD组间差异大（厚度分组CC位：F=35.29、31.32,P<0.005;MLO位：F=44.83、27.02,P<0.005;Q_abd分类CC位：F=18.68、19.76,P<0.005;MLO位：F=4.58、10.52,P<0.005）;Q_abd分类高的乳房平均压迫厚度较低（CC位：F=16.28,P<0.005;MLO位：F=17.81,P<0.005）;同时考虑压迫厚度与乳房密度交互作用影响,仅在MLO位DM模式对AGD有交互作用（F=3.16,P=0.005）。结论 DBT/FFDM两种模式剂量累积可能增加辐射风险;乳腺摄影优先采用单视图CC/MLO-DBT或CC/MLO-（DBT+FFDM）+单视图MLO/CC-FFDM模式,在减低辐射剂量风险方面有积极作用。     

Prospective trial comparing full-field digital mammography (FFDM) versus combined FFDM and tomosynthesis in a population-based screening programme using independent double reading with arbitration

Objectives

To compare double readings when interpreting full field digital mammography (2D) and tomosynthesis (3D) during mammographic screening.

Methods

A prospective, Ethical Committee approved screening study is underway. During the first year 12,621 consenting women underwent both 2D and 3D imaging. Each examination was independently interpreted by four radiologists under four reading modes: Arm A—2D; Arm B—2D?+?CAD; Arm C—2D?+?3D; Arm D—synthesised 2D?+?3D. Examinations with a positive score by at least one reader were discussed at an arbitration meeting before a final management decision. Paired double reading of 2D (Arm A?+?B) and 2D?+?3D (Arm C?+?D) were analysed. Performance measures were compared using generalised linear mixed models, accounting for inter-reader performance heterogeneity (P?<?0.05).

Results

Pre-arbitration false-positive scores were 10.3 % (1,286/12,501) and 8.5 % (1,057/12,501) for 2D and 2D?+?3D, respectively (P?<?0.001). Recall rates were 2.9 % (365/12,621) and 3.7 % (463/12,621), respectively (P?=?0.005). Cancer detection was 7.1 (90/12,621) and 9.4 (119/12,621) per 1,000 examinations, respectively (30 % increase, P?<?0.001); positive predictive values (detected cancer patients per 100 recalls) were 24.7 % and 25.5 %, respectively (P?=?0.97). Using 2D?+?3D, double-reading radiologists detected 27 additional invasive cancers (P?<?0.001).

Conclusion

Double reading of 2D?+?3D significantly improves the cancer detection rate in mammography screening.

Key Points

? Tomosynthesis-based screening was successfully implemented in a large prospective screening trial. ? Double reading of tomosynthesis-based examinations significantly reduced false-positive interpretations. ? Double reading of tomosynthesis significantly increased the detection of invasive cancers.     

Low energy mammogram obtained in contrast-enhanced digital mammography (CEDM) is comparable to routine full-field digital mammography (FFDM)

Purpose

Contrast enhanced digital mammography (CEDM) uses low energy and high energy exposures to produce a subtracted contrast image. It is currently performed with a standard full-field digital mammogram (FFDM). The purpose is to determine if the low energy image performed after intravenous iodine injection can replace the standard FFDM.

Methods

And Materials: In an IRB approved HIPAA compatible study, low-energy CEDM images of 170 breasts in 88 women (ages 26–75; mean 50.3) undergoing evaluation for elevated risk or newly diagnosed breast cancer were compared to standard digital mammograms performed within 6 months. Technical parameters including posterior nipple line (PNL) distance, compression thickness, and compression force on the MLO projection were compared. Mammographic findings were compared qualitatively and quantitatively. Mixed linear regression using generalized estimating equation (GEE) method was performed. Intraclass correlation coefficients (ICC) with 95% confidence interval (95%CI) were estimated to assess agreement.

Results

No statistical difference was found in the technical parameters compression thickness, PNL distance, compression force (p-values: 0.767, 0.947, 0.089). No difference was found in the measured size of mammographic findings (p-values 0.982–0.988). Grouped calcifications had a mean size/extent of 2.1 cm (SD 0.6) in the low-energy contrast images, and a mean size/extent of 2.2 cm (SD 0.6) in the standard digital mammogram images. Masses had a mean size of 1.8 cm (SD 0.2) in both groups. Calcifications were equally visible on both CEDM and FFDM.

Conclusion

Low energy CEDM images are equivalent to standard FFDM despite the presence of intravenous iodinated contrast. Low energy CEDM images may be used for interpretation in place of the FFDM, thereby reducing patient dose.     

全数字乳腺X线3种摄影模式的影像质量和辐射剂量比较

目的 探讨全数字乳腺X线摄影(FFDM)不同摄影模式影像质量与辐射剂量的比较研究.方法 用全数字乳腺X线摄影的对比度优先模式(CNT)、标准模式(STD)及辐射剂量优先模式(DOSE)对FLUKE NA 18-220乳腺模体进行摄影,摄影采用自动曝光模式(AEC),记录摄影条件和辐射剂量.由4位影像学医师在相同条件下进行软阅读,并按照美国放射学会(ACR)的评分标准对模体中的钙化点、尼龙纤维、肿块灶进行评分.结果 标准模式、辐射剂量优先模式及对比度优先模式的模体影像评分值分别是11.5、11.0和14.5,标准模式及辐射剂量优先模式与对比度优先模式的影像质量差异有统计学意义(F=41.321,P＜0.05).标准模式与辐射剂量优先模式之间影像质量差异无统计学意义,但两种模式的辐射剂量却不相同,其表面入射剂量分别是4.5和3.15 mGy,腺体平均剂量(AGD)分别是1.18和0.78 mGy.结论 全数字乳腺摄影的辐射剂量优先模式和标准模式适合大多数被检者,特别是辐射剂量优先模式.对比度优先模式应严格控制使用.

Abstract：

Objective To study the difference of image quality and radiation dose between different exposure modes with full-field digital mammography (FFDM).Methods The Fluke18-220mammographic phantom was exposed by FFDM system with different exposure modes at automatic exposure control ( AEC ) ,including contrast mode,standard mode and dose mode,and the exposure factors and radiation dose were recorded.The images on monitor with the best window width and window level were read by four independent radiologists.The images of specks groups,nylon fibers and masses was assessed by the four experienced readers at the criterion of American College of Radiology.Results The detection of specks groups,nylon fibers and masses were statistically different at the contrast mode and standard mode (F =41.321,P ＜ 0.05),further at the contrast mode and dose mode.The detection of specks groups、nylon fibers and masses were not statistically different( P ＞ 0.05 ) at standard mode and dose mode,but the radiation doses were different.The ESD at standard mode and dose mode was 4.5 and 3.15 mGy,respectively.The AGD of standard mode and dose mode was 1.18 mGy and 0.78 mGy,respectively.Conclusions The standard mode and dose mode of FFDM might be fit for most patients,especially at the dose mode.Contrast mode of FFDM should be strictly controled in use.     

Comparison of full-field digital mammography and film-screen mammography: image quality and lesion detection

The objective of this study is to compare image quality and lesion detection for full field digital mammography (FFDM) and film-screen mammography (FSM). In 200 women we performed digital mammography of one breast and film-screen mammography of the other breast. Imaging parameters were set automatically. Image quality, visualization of calcifications and masses were rated by three readers independently. Mean glandular dose was calculated for both systems. We found no significant difference in mean glandular dose. Image quality was rated by reader A/B/C as excellent for FFDM in 153/155/167 cases and for FSM in 139/116/114 cases (p<0.03/0.001/0.001). Microcalcifications were detected by FFDM in 103/89/98 and by FSM in 76/76/76 cases (p<0.01/0.06/0.01). Detection of masses did not differ significantly. FFDM provided significantly better visibility of skin and nipple-areola region (p<0.01). FFDM demonstrated improved image quality compared with film-screen mammography. Microcalcification detection was also significantly better with the digital mammography system for two of the three readers.     

Accuracy in tumor size measurements: Comparison of digital mammography,digital breast tomosynthesis and synthetic mammography

PurposeThe aim of this study was to assess the accuracy of digital mammography (DM), digital breast tomosynthesis (DBT) and synthetic mammography (SM) in tumor size measurements compared with histological tumor sizes.Materials and methods71 breast cancer patients who underwent DM and DBT acquisitions simultaneously were included in this study. One radiologist with 8 years of experience in breast imaging measured tumor sizes independently in three separate sessions which include DM, DBT and SM images, respectively. The correlations between the measured tumor sizes on each imaging technique and histological sizes were analyzed using Spearman correlation test. The patients were categorized into two subgroups according to assigned breast density categories (dense and non-dense), and histological tumor sizes (≤2 cm and > 2 cm). To assess the agreement levels between the measured tumor sizes and histological sizes Bland-Altman analyses were performed for each imaging technique.ResultsThe mean of histological size of tumors was 23.85 ± 16.57 mm (median: 20). The means of measured tumor sizes were 21.21 ± 13.59 mm (median: 19), 21.52 ± 13.42 mm (median: 19) and 18.97 ± 11.21 mm (median: 17) in DM, DBT and SM, respectively. The Spearman correlation values with histologic sizes were 0.814 (P < 0.001), 0.887 (P < 0.001), and 0.852 (P < 0.001) for DM, DBT and SM, respectively. In subgroup analyses, the correlation values showed decrement for tumors >2 cm in size compared to tumors ≤2 cm in size.ConclusionDBT provides the most accurate tumor size measurements among mammographic imaging techniques and if mammography will be used in tumor size measurements, DBT should be preferred.     

Effects on short-term quality of life of vacuum-assisted breast biopsy: comparison between digital breast tomosynthesis and digital mammography

Objective:

To compare the effects of digital breast tomosynthesis (DBT)-guided and digital mammography (MMx)-guided vacuum-assisted breast biopsy (VABB) on short-term quality of life (QoL).

Methods:

From November 2014 through March 2015, females undergoing VABB in an academic medical centre participated in a survey after biopsy. VABB was performed under DBT (Group 1) or MMx guidance (Group 2). Biopsy experience was assessed with a modified testing morbidities index (TMI). 10 attributes were assessed: six related to the procedures (pain or discomfort before and during testing, fear or anxiety before and during testing, physical and mental function after testing) and four not related to the procedures (familiarity for cancer and clinical history, embarrassment during testing and overall satisfaction). Non-parametric standard statistics were used to compare data of Group 1 and data of Group 2.

Results:

A total of 90 females (mean age, 55.8 years; range, 40–87 years) were enrolled: 45 underwent DBT-VABB and 45 MMx-VABB. The sum of the 6 of 10 items related to the procedures was significantly worse for DBT (p < 0.02), but no differences were observed for the single items. The median value for DBT-VABB and MMx-VABB was 95.2 and 90.1, respectively (p < 0.02). The 4 of 10 TMI items not related to the procedures did not differ significantly between the two groups. Four females fainted during DBT-VABB and three females during MMx-VABB; all of these patients underwent VABB procedures in sitting position.

Conclusion:

Females in the DBT-VABB study group have a decreased short-term QoL compared with the MMx-VABB group. DBT-VABBs were less tolerated than MMx-VABBs.

Advances in knowledge:

DBT-VABB was less tolerated than MMx-VABB. Females in the DBT-VABB study group had a decreased short-term QoL compared with the MMx-VABB group. Overall satisfaction was similar for both procedures.     

Radiation dose with digital breast tomosynthesis compared to digital mammography: per-view analysis

Objectives

To compare radiation dose delivered by digital mammography (FFDM) and breast tomosynthesis (DBT) for a single view.

Methods

4,780 FFDM and 4,798 DBT images from 1,208 women enrolled in a screening trial were used to ground dose comparison. Raw images were processed by an automatic software to determine volumetric breast density (VBD) and were used together with exposure data to compute the mean glandular dose (MGD) according to Dance’s model. DBT and FFDM were compared in terms of operation of the automatic exposure control (AEC) and MGD level.

Results

Statistically significant differences were found between FFDM and DBT MGDs for all views (CC: MGD_FFDM=1.366 mGy, MGD_DBT=1.858 mGy; p<0.0001; MLO: MGD_FFDM=1.374 mGy, MGD_DBT=1.877 mGy; p<0.0001). Considering the 4,768 paired views, Bland-Altman analysis showed that the average increase of DBT dose compared to FFDM is 38 %, and a range between 0 % and 75 %.

Conclusions

Our findings show a modest increase of radiation dose to the breast by tomosynthesis compared to FFDM. Given the emerging role of DBT, its use in conjunction with synthetic 2D images should not be deterred by concerns regarding radiation burden, and should draw on evidence of potential clinical benefit.

Key Points

? Most studies compared tomosynthesis in combination with mammography vs. mammography alone. ? There is some concern about the dose increase with tomosynthesis. ? Clinical data show a small increase in radiation dose with tomosynthesis. ? Synthetic 2D images from tomosynthesis at zero dose reduce potential harm. ? The small dose increase should not be a barrier to use of tomosynthesis.

     

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.     

Combination of one-view digital breast tomosynthesis with one-view digital mammography versus standard two-view digital mammography: per lesion analysis

Objective

To evaluate the clinical value of combining one-view mammography (cranio-caudal, CC) with the complementary view tomosynthesis (mediolateral-oblique, MLO) in comparison to standard two-view mammography (MX) in terms of both lesion detection and characterization.

Methods

A free-response receiver operating characteristic (FROC) experiment was conducted independently by six breast radiologists, obtaining data from 463 breasts of 250 patients. Differences in mean lesion detection fraction (LDF) and mean lesion characterization fraction (LCF) were analysed by analysis of variance (ANOVA) to compare clinical performance of the combination of techniques to standard two-view digital mammography.

Results

The 463 cases (breasts) reviewed included 258 with one to three lesions each, and 205 with no lesions. The 258 cases with lesions included 77 cancers in 68 breasts and 271 benign lesions to give a total of 348 proven lesions. The combination, DBT_(MLO)+MX_(CC), was superior to MX (CC+MLO) in both lesion detection (LDF) and lesion characterization (LCF) overall and for benign lesions. DBT_(MLO)+MX_(CC) was non-inferior to two-view MX for malignant lesions.

Conclusions

This study shows that readers’ capabilities in detecting and characterizing breast lesions are improved by combining single-view digital breast tomosynthesis and single-view mammography compared to two-view digital mammography.

Key Points

? Digital breast tomosynthesis is becoming adopted as an adjunct to mammography (MX) ? DBT _(MLO) +MX _(CC) is superior to MX _(CC+MLO) in lesion detection (overall and benign lesions) ? DBT _(MLO) +MX _(CC) is non-inferior to MX _(CC+MLO) in cancer detection ? DBT _(MLO) +MX _(CC) is superior to MX _(CC+MLO) in lesion characterization (overall and benign lesions) ? DBT _(MLO) +MX _(CC) is non-inferior to MX _(CC+MLO) in characterization of malignant lesions     

全数字乳腺摄影系统与双面阅读CR乳腺摄影系统的比较

目的 对比研究全数字乳腺摄影系统(FFDM)与双面阅读CR乳腺摄影成像系统(DSCRM)辐射剂量与成像质量的关系.方法 在相同的辐射剂量下用FFDM和DSCRM对ALVIM统计学乳腺摄影模体TRM进行曝光,记录摄影条件和模体表面入射剂量,然后固定此摄影条件kV值,选用不同mAs值用DSCRM对模体进行曝光,记录表面入射剂量,并将所获取的影像在图像诊断工作站显示器上由3位放射学专家进行视读打分,按照5分值判断法评判,绘制ROC曲线,计算出每种信号的判断概率值Pdet,对所得数据进行统计学分析.结果 在辐射剂量为1.36 mGy时,FFDM所摄取模体影像内容物中不同直径钙化点和肿块灶的Pdet值分别是0.730 ～0.925和0.670～0.945,DSCRM所得模体影像内容物中不同直径钙化点和肿块灶的Pdet值分别是0.632～0.815和0.575～0.785.二者在1.35 mm肿块灶和0.40 mm钙化点用双因素方差分析(ANOVA)进行处理,(F=37.1,P＜0.05).在相同的判断概率值Pdet下,DSCRM所用表面入射剂量为1.63 mGy,腺体平均剂量为0.65 mGy,FFDM所用的表面入射剂量为1.36 mGy,腺体平均剂量为0.56 mGy,FFDM较DSCRM表面入射剂量减少了19.8％,腺体平均剂量减少16.0％.结论 在相同曝光条件下,FFDM对模体内容物的检出率高于DSCRM;在获得相似图像质量时,FFDM的辐射剂量明显低于DSCRM.     

Estimation of percentage breast tissue density: comparison between digital mammography (2D full field digital mammography) and digital breast tomosynthesis according to different BI-RADS categories

Objective:

To compare breast density estimated from two-dimensional full-field digital mammography (2D FFDM) and from digital breast tomosynthesis (DBT) according to different Breast Imaging–Reporting and Data System (BI-RADS) categories, using automated software.

Methods:

Institutional review board approval and written informed patient consent were obtained. DBT and 2D FFDM were performed in the same patients to allow within-patient comparison. A total of 160 consecutive patients (mean age: 50±14 years; mean body mass index: 22±3) were included to create paired data sets of 40 patients for each BI-RADS category. Automatic software (MedDensity^©, developed by Giulio Tagliafico) was used to compare the percentage breast density between DBT and 2D FFDM. The estimated breast percentage density obtained using DBT and 2D FFDM was examined for correlation with the radiologists'' visual BI-RADS density classification.

Results:

The 2D FFDM differed from DBT by 16.0% in BI-RADS Category 1, by 11.9% in Category 2, by 3.5% in Category 3 and by 18.1% in Category 4. These differences were highly significant (p<0.0001). There was a good correlation between the BI-RADS categories and the density evaluated using 2D FFDM and DBT (r=0.56, p<0.01 and r=0.48, p<0.01, respectively).

Conclusion:

Using DBT, breast density values were lower than those obtained using 2D FFDM, with a non-linear relationship across the BI-RADS categories. These data are relevant for clinical practice and research studies using density in determining the risk.

Advances in knowledge:

On DBT, breast density values were lower than with 2D FFDM, with a non-linear relationship across the classical BI-RADS categories.To tailor screening and diagnosis protocols, it is important to identify females with an increased risk of breast cancer [1–3]. It has been estimated that females with dense breasts (breast densities of >75%) have 4–6 times higher risk of breast cancer than females with low breast densities [4] and that breast density is increasingly recognised as an independent determinant of breast cancer risk and possibly in prognosis [5]. Assessment of breast density is becoming crucial in epidemiological studies, including the estimation of breast cancer risk and assessing breast density-related risk over time, radiation dose monitoring and monitoring drug-related response [6,7].Different methods and classifications have been reported to assess breast density: the Tabar classification [8], Wolfe''s parenchymal patterns [9], and both semi-quantitative and quantitative computer-aided techniques [10–16]. The Breast Imaging–Reporting and Data System (BI-RADS) classification, considered as the additional quantitative scheme, is routinely used in the USA and was introduced to standardise reporting. Initially, it was based on four qualitative categories but an additional quantitative scheme was added in 2003, based on the extent of fibroglandular tissue [17]. Mammographic breast density estimation may be limited by the two-dimensional (2D) nature of the imaging technique, whereas a three-dimensional (3D) imaging modality, such as digital breast tomosynthesis (DBT), reduces the appearance of the overlapping parenchymal tissue and may therefore influence or alter density assessments [13,14]. In DBT, high-spatial-resolution tomographic images of the breast are reconstructed from multiple low-dose projection images acquired within a limited range of X-ray tube angles [15]. It has been demonstrated in a few studies that the automated estimation of breast density eliminates subjectivity between comparisons of full-field digital mammography (2D FFDM) and DBT and is more reproducible than a quantitative BI-RADS evaluation [14,16]. However, previous research mainly considered patients with relatively high breast density, with the possibility of the results not being applicable across all density categories and showing whether published percentage breast density differences between 2D FFDM and DBT apply to less dense or non-dense breasts. The purpose of our study was to compare the breast tissue density estimated using 2D FFDM and DBT among patients in a balanced data set of the four BI-RADS categories, using fully automated software.     

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.     

Diagnostic value of the stand-alone synthetic image in digital breast tomosynthesis examinations

Objective

To demonstrate the non-inferiority of synthetic image (SI) mammography versus full-field digital mammography (FFDM) in breast tomosynthesis (DBT) examinations.

Methods

An observational, retrospective, single-centre, multireader blinded study was performed, using 2384 images to directly compare SI and FFDM based on Breast Imaging Reporting and Data System (BIRADS) categorisation and visibility of radiological findings. Readers had no access to digital breast tomosynthesis slices. Multiple reader, multiple case (MRMC) receiver operating characteristic (ROC) methodology was used to compare the diagnostic performance of SI and FFDM images. The kappa statistic was used to estimate the inter-reader and intra-reader reliability.

Results

The area under the ROC curves (AUC) reveals the non-inferiority of SI versus FFDM based on BIRADS categorisation [difference between AUC (ΔAUC), -0.014] and lesion visibility (ΔAUC, -0.001) but the differences were not statistically significant (p=0.282 for BIRADS; p=0.961 for lesion visibility). On average, 77.4% of malignant lesions were detected with SI versus 76.5% with FFDM. Sensitivity and specificity of SI are superior to FFDM for malignant lesions scored as BIRADS 5 and breasts categorised as BIRADS 1.

Conclusions

SI is not inferior to FFDM when DBT slices are not available during image reading. SI can replace FFDM, reducing the dose by 45%.

Key Points

? Stand-alone SI demonstrated performance not inferior for lesion visibility as compared to FFDM.? Stand-alone SI demonstrated performance not inferior for lesion BIRADS categorisation as compared to FFDM.? Synthetic images provide important dose savings in breast tomosynthesis examinations.