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.     

Aktueller Stand und weitere Perspektiven der digitalen Mammographie

Digital mammography has extensively replaced conventional film screen mammography and is now the standard in combination with soft copy reading in clinical as well as screening mammography. Large international multicenter studies demonstrate an equivalent or superior detection rate of breast cancers by digital in comparison to conventional mammography especially in dense breasts, premenopausal and perimenopausal women and women less than 50 years old. Computer-aided detection (CAD) is important for the experienced investigator (increased specificity). Digital mammography also offers further options, such as tomosynthesis, digital contrast-enhanced mammography and the combination of digital mammography and ultrasound. The future in breast diagnosis will be the fusion of images from different digital systems.     

数字乳腺X线摄影技术的研究进展

随着数字化乳腺X线检查技术的发展,屏/片系统乳腺X线摄影(SFM)技术已逐步被取代,一些技术改进的优势已在致密型乳腺的女性中得到证实。比较数字乳腺体层摄影(DBT)技术、对比增强双能数字乳腺X线摄影(CEDM)技术及常规数字乳腺X线摄影(DM)技术,并综述数字乳腺摄影技术发展中一些新技术的特点,分析其优势、局限性及对病人的潜在影响等,从而预测它们的发展前景。     

Initial clinical experience with contrast-enhanced digital breast tomosynthesis

RATIONALE AND OBJECTIVES: 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). MATERIALS AND METHODS: 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. RESULTS: Initial experience suggests that CE-DBT provides morphologic and vascular characteristics of breast lesions qualitatively concordant with that of digital mammography and MR. CONCLUSION: As an adjunct to digital mammography, CE-DBT may be a potential alternative tool for breast lesion morphologic and vascular characterization.     

Emerging technologies in breast cancer detection

While screening mammography is recognized as the most effective method for early detection of breast cancer, this modality has limitations that are the driving force behind efforts to refine existing mammography technologies and develop new ones offering improved detection of breast cancer. Full-field digital mammography (FFDM) systems use digital detectors to convert x-ray photons to digital signals for display on high-resolution monitors. These systems offer capabilities not provided by conventional film-screen mammography. Contrast-enhanced mammography utilizes the basic biological principle that aggressive cancers are associated with increased vascularity. Iodinated contrast agents--the same used in computed tomography (CT) examinations--are administered through an injection in a vein usually in the arm. They distribute throughout the blood system, and x-ray imaging shows increased contrast in areas where they concentrate. Tomosynthesis acquisition involves acquiring multiple images of a stationary compressed breast at different angles during a short scan. The individual images are then reconstructed into a 3D series of thin high-resolution slices. The slices can be displayed individually or in a dynamic ciné mode. The individual slices reduce tissue overlap and structure noise relative to standard 2D projection mammography, with a total dose comparable to that required for standard screening mammography. Initial efforts are underway to develop prototype systems to achieve high-resolution, whole-breast 3D ultrasound images that are co-registered with digital mammograms. This technology has the potential to improve specificity in breast imaging studies, particularly in dense breasts. Computer-aided detection (CAD) programs are intended to help radiologists identify suspicious lesions that may otherwise be overlooked. CAD software works similarly to a spellchecker and has the potential to increase the detection of cancer Magnetic resonanace imaging (MRI) is a generally accepted diagnostic procedure for a number of breast related indications. Its greatest strength is that it is very sensitive to tumors. If a suspected area does not exhibit contrast agent uptake, the probability that it is malignant is very small. Conversely, its specificity is poorer. If the area does show enhancement, it may or may not be a tumor. Further imaging or biopsy may be needed to resolve the question. Ultrasound holds promise as a method for detection of cancers in women with dense breast tissue, which is often problematic with conventional film-screen mammography. Ultrasound has also assumed an important role in breast imaging, as an adjunct to diagnostic mammography for biopsy guidance, palpable mass evaluation, and serial evaluation of benign masses.     

Digital mammography: what do we and what don’t we know?

High-quality full-field digital mammography has been available now for several years and is increasingly used for both diagnostic and screening mammography. A number of different detector technologies exist, which all have their specific advantages and disadvantages. Diagnostic accuracy of digital mammography has been shown to be at least equivalent to film-screen mammography in a general screening population. Digital mammography is superior to screen-film mammography in younger women with dense breasts due to its ability to selectively optimize contrast in areas of dense parenchyma. This advantage is especially important in women with a genetic predisposition for breast cancer, where intensified early detection programs may have to start from 25 to 30 years of age. Tailored image processing and computer-aided diagnosis hold the potential to further improve the early detection of breast cancer. However, at present no consensus exists among radiologists on which processing is optimal for digital mammograms. Image processing may also vary significantly among vendors with so far limited interoperability. This review aims to summarize the available information regarding the impact of digital mammography on workflow and breast cancer diagnosis.     

Comparison of screening CEDM and MRI for women at increased risk for breast cancer: A pilot study

ObjectivesContrast enhanced digital mammography (CEDM) is a new breast imaging technology increasingly used in the diagnostic setting but its utility in the pure screening setting has not been reported. The goal of this pilot study is to prospectively compare screening CEDM to breast MRI in women with an increased risk for breast cancer.MethodsIn this IRB-approved HIPAA-compliant study, 318 women at increased breast cancer risk were consented (December 2012–May 2015) to undergo CEDM in addition to their scheduled MRI. CEDM was performed within 30 days of screening MRI. CEDM was interpreted blinded to MRI. The reference standard was defined as a combination of pathology and 2-year imaging follow-up.ResultsData from 307/318 patients were evaluable. Three cancers (two invasive cancers, one ductal carcinoma in situ) were detected at first round screening: MRI detected all three and CEDM detected the two invasive cancers. None of the three cancers was seen on the low energy mammograms which are comparable to conventional mammography. At 2 year imaging follow up, there were 5 additional screen detected cancers and no palpable cancers. The positive predictive value 3 (PPV₃) for CEDM was 15% (2/13, 95% CI: 2–45%) and 14% for MRI (3/21, 95% CI: 3–36%). The specificity of CEDM and MRI were 94.7% and 94.1% respectively.ConclusionsBoth CEDM and MRI detected additional cancers not seen on conventional mammography, primarily invasive cancers. Our pilot data suggest that CEDM could be valuable as a supplemental imaging exam for women at increased risk for breast cancer who do not meet the criteria for MRI or for whom access to MRI is limited. Validation in larger multi institutional trials is warranted.     

Digital mammography: current state and future aspects

The introduction of digital technique in mammography has been the last step in completing the process of digitalization in diagnostic imaging. Meanwhile, some different digital techniques as well as a couple of different digital mammography systems were developed and have already been available for some years. In this review article, the relevant data of key studies are reported, the current status is defined, and perspectives of digital mammography are described.     

Diffusion-weighted MRI as an adjunct to mammography in women under 50 years of age: an initial study

Purpose:

To evaluate diffusion‐weighted magnetic resonance (DW) imaging as an adjunct to mammography for the detection of small invasive breast cancer.

Materials and Methods:

Institutional review board standards were followed for this retrospective study. We performed both breast DW imaging and mammography on 25 women under 50 years of age with pathologically proven T1 breast cancer and on 21 healthy women under 50 years of age. Four offsite radiologists blind to the clinical information independently interpreted the mammograms and DW images and then classified their confidence level regarding the presence of breast cancer. The composite area under receiver operating characteristic curve (AUC), of mammography alone, DW imaging alone, and the combination of DW imaging and mammography (DWI/Cal) were calculated.

Results:

The AUC of composite ROC curves of mammography, DW imaging, DWI/Cal combination, was 0.79 (95% CI, 0.72–0.87), 0.86 (95% CI, 0.84–0.87), and 0.96 (95% CI, 0.92–1.00), respectively.

Conclusion:

DW imaging may be a useful adjunct to mammography in the detection of small invasive breast cancer in women under 50 years of age. J. Magn. Reson. Imaging 2012;36:139–144. © 2012 Wiley Periodicals, Inc.     

Perspektiven der digitalen Mammographieplattform

In Europe one out of every nine women suffers from breast cancer during her lifetime. Since the introduction of mammography screening programs more breast cancers are being diagnosed when they are still small and early stage cancers with a favourable prognosis. The introduction of digital mammography systems has led to a continuous reduction of breast cancer mortality especially in specific patient subgroups. Furthermore, the digital mammography platform enables the development of new, innovative breast imaging methods to increase sensitivity and decrease breast cancer mortality. This digital mammography platform includes digital breast tomosynthesis, digital contrast medium mammography and digital contrast medium breast tomosynthesis as well as fused data sets from digital mammography with ultrasound or MRI. The following article summarizes these new applications, describes the strengths of the digital platform and illustrates the potential advantages of an improved breast cancer diagnosis by digital mammography.     

全数字化乳腺摄影对乳腺疾病的诊断价值

目的 评价全数字化乳腺摄影在临床中对乳腺疾病的诊断价值.方法 回顾215例经手术或活检的术前全数字化乳腺摄影资料,对比影像诊断与最终病理诊断异同.分析不同疾病的误诊原因,初步分析及探讨全数字化乳腺摄影对乳腺疾病的诊断价值.结果 215例经手术或活检的病例中,132例被病理确诊为乳腺癌,83例被诊断为良性病变.在被病理证实为乳腺癌的132例乳腺癌病例中,14例被全数字化乳腺摄影诊断漏诊或误诊.而同时被影像诊断为恶性病变可能的130例(BI-RADS大于4级)的病例中,12例最终病理诊断确定为良性病变.结论 全数字化乳腺摄影是乳腺疾病的重要检查手段,尤其对发现及筛查乳腺癌具有重要价值,但对某些乳腺良性病变,其诊断准确率较低,需要结合其他临床诊断方式.     

Direct digital mammography image acquisition

Mammography is a branch of radiology which could benefit greatly from the assimilation of digital imaging technologies. Computerized enhancement techniques could be used to ensure optimum presentation of all clinical images. Beyond this it will facilitate powerful new clinical resources such as computer-assisted diagnosis, tele-mammography, plus digital image management and archiving. An essential precursor to all these advances is the availability of appropriate direct digital mammography (DDM) image-acquisition system(s) to capture high-quality breast X-ray image data at the outset. The only practical DDM image-acquisition system currently available is (photo-stimulable phosphor) computed radiography. Modern computed mammography (CM) uses similar radiation doses to the patient and produces equivalent, albeit different, image quality to screen-film mammography. Computed mammography offers superior rendition of the skin edge and sub-cutaneous tissue and dense parenchyma, while ensuring equivalent micro-calcification detectability. Meanwhile, a variety of new technical approaches to DDM are under active investigation and/or development which promise to supercede film-based mammography. These new (second generation) DDM technologies promise the radiologist superior image quality combined with significant dose savings compared with contemporary imaging systems. In this review we describe and compare the physical and clinical characteristics of CM and the various emerging DDM image-acquisition technologies. Received 4 April 1996; Revision received 28 June 1996; Accepted 21 August 1996     

数字乳腺X线摄影:男性乳腺疾病诊断的推荐检查可行性分析

目的 基于敏感性、特异性等指标的评价,探讨数字乳腺X线摄影及超声对男性乳腺病变的诊断价值.方法 选取79例行乳腺X线摄影检查的男性乳腺肿块病例,部分病例同时行超声检查(62例).乳腺病灶评价依据2013版BI-RADS,通过2位高年资乳腺放射医师对征象进行分析后作出BI-RADS分类,并将BI-RADS 4a类以上定义...     

钼靶X线、超声组合BI-RADS分类法指导农村妇女乳腺普查

目的:探讨应用钼钯X线(MAM)、超声(US)组合BI-RADS分类法确定农村妇女乳腺癌普查年龄的可行性。方法:954例本地区农村妇女,年龄35～60岁,平均(47.5±5.8)岁。所有妇女均接受US和MAM检查并行BI-RADS分类,US+MAM组合分类结果为每例受检者US与MAM分类结果中的最高级别,US+MAM分类Ⅲ类以上结果判定为高危人群并随访。将954例农村妇女及所检出的高危妇女划分为35～40岁、41～50岁、51～60岁3个年龄段,计算高危妇女在其相应年龄段所占比率,统计学分析其差异。结果:44例农村妇女被组合BI-RADS分类法评价为高危妇女,其随访结果与BI-RADS要求相符,35～40岁、41～50岁、51～60岁3个年龄段高危妇女所占比率分别为8.21%、5.32%、1.70%,其差异有统计学意义(P<0.05)。结论:应用US+MAM组合法BI-RADS分类可准确判定农村妇女乳腺癌的普查年龄。     

Mamografía con realce de contraste mediante técnica de energía dual

The degree of vascularization in breast lesions is related to their malignancy. For this reason, functional diagnostic imaging techniques have become important in recent years. Dual-energy contrast-enhanced mammography is a new, apparently promising technique in breast cancer that provides information about the degree of vascularization of the lesion in addition to the morphological information provided by conventional mammography. This article describes the state of the art for dual-energy contrast-enhanced mammography. Based on 15 months’ clinical experience, we illustrate this review with clinical cases that allow us to discuss the advantages and limitations of this technique.     

Digitale Brusttomosynthese

In recent years digital full field mammography has increasingly replaced conventional film mammography. High quality imaging is guaranteed by high quantum efficiency and very good contrast resolution with optimized dosing even for women with dense glandular tissue. However, digital mammography remains a projection procedure by which overlapping tissue limits the detectability of subtle alterations. Tomosynthesis is a procedure developed from digital mammography for slice examination of breasts which eliminates the effects of overlapping tissue and allows 3D imaging of breasts. A curved movement of the X-ray tube during scanning allows the acquisition of many 2D images from different angles. Subseqently, reconstruction algorithms employing a shift and add method improve the recognition of details at a defined level and at the same time eliminate smear artefacts due to overlapping structures. The total dose corresponds to that of conventional mammography imaging. The technical procedure, including the number of levels, suitable anodes/filter combinations, angle regions of images and selection of reconstruction algorithms, is presently undergoing optimization. Previous studies on the clinical value of tomosynthesis have examined screening parameters, such as recall rate and detection rate as well as information on tumor extent for histologically proven breast tumors. More advanced techniques, such as contrast medium-enhanced tomosynthesis, are presently under development and dual-energy imaging is of particular importance.     

数字乳腺断层摄影及其合成二维影像技术在乳腺癌筛查中的研究进展

目前乳腺X线检查仍是乳腺癌早期诊断的有效检查方法之一,主要包括全视野数字化乳腺摄影（FFDM）、数字乳腺断层摄影（DBT）、合成乳腺X线摄影（SM）以及3种技术的联合应用（FFDM联合DBT、SM联合DBT）。对DBT、SM和SM联合DBT在乳腺筛查中诊断效能、影像质量及辐射剂量等进行比较。SM联合DBT可有效平衡辐射剂量和诊断效能,但仍然在判读时间、信息的存储与传输和检查成本方面存在局限性。就以上3种检查技术在乳腺癌筛查中的研究进展予以综述。     

Near monochromatic X-rays for digital slot-scan mammography: initial findings

X-ray spectra are composed of a broad bremsspectrum and anode-characteristic emission lines. In mammography typically molybdenum (Mo), rhodium (Rh) or tungsten (W) anodes are used in combination with Mo, Rh or aluminium filters. Only the photons with energies between 17 and 22 keV of the resulting spectrum are suitable for the soft tissue imaging needed for mammography. The aim of this article is to present first results obtained with a monochromator module mounted at the exit of the X-ray tube of a conventional clinical mammography unit. The experimental setup consists of a Siemens Mammomat 300, an X-ray monochromator module and a linear array detector for image acquisition. The technique is similar to the slot-scan technique known from digital mammography. The experimental machine allows to obtain images both with polychromatic and monochromatic X-rays. Initial evaluation of the system was performed by examination of a contrast-detail phantom (CD-MAM-phantom, Nijmegen, The Netherlands). Images done with the new monochromatic technique were compared to images of the phantom done with polychromatic spectra, with film-screen mammography as well as with digital mammography. The new technique with monochromatic slot-scan mammography resulted in correct identification of 93% of the phantom. Digital slot-scan mammography with polychromatic beam resulted in correct identification of 87%, digital full-field mammography in 83% and conventional film-screen mammography in 70% of the phantom. The results suggest that monochromatization has a potential for improving image quality or decreasing dose in X-ray mammography.     

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。     

Variable Appearances of Ductal Carcinoma In Situ Calcifications on Digital Mammography,Synthesized Mammography,and Tomosynthesis: A Pictorial Essay

This pictorial essay demonstrates the variable appearances of ductal carcinoma in situ on full-field digital mammography, synthesized mammography, and digital breast tomosynthesis. The spectrum of intercase and intracase variability suggests further refinement of reconstruction algorithms for synthesized mammography may be necessary to maximize early detection of ductal carcinoma in situ.