[Comparison of dignity determination of mammographic microcalcification with two systems for digital full-field mammography with different detector resolution: a retrospective clinical study]. / Vergleich der Dignitätsbestimmung von mammographischem Mikrokalk mit zwei Systemen zur digitalen Vollfeldmammographie unterschiedlicher Detektorauflösung : Eine retrospektive klinische Studie.

PURPOSE: The aim of this retrospective clinical study was to compare the diagnostic accuracy of the novel 50 µm FFDM (full-field digital mammography) system (DR) with an established 70 µm system (DR) in the differential diagnosis between benign and malignant clusters of microcalcification (n=50) (BI-RADS™ classification 4/5) and to assess the possible incremental value of the 50 µm pixel-pitch on specificity. MATERIAL AND METHODS: From March 2009 to September 2009, 50 patients underwent full-field digital mammography (FFDM) (detector resolution 70 µm) (Novation, Siemens, Erlangen, Germany). As there were suspicious signs of microcalcification classified with BI-RADS™ 4/5 after diagnosis and preoperative wire localization, control images were made with the new FFDM system (detector: resolution 50 µm) (Amulet, Fujifilm, Tokyo, Japan) with the same exposure parameters. The diagnosis was determined after the operation by five radiologists with different experience in digital mammography from randomly distributed mediolateral views (monitor reading) whose results were correlated with the final histology of all lesions. RESULTS: Histopathology revealed 19 benign and 31 malignant lesions in 50 patients after open biopsy. The results of the five readers showed a higher sensitivity of the new FFDM system (80.0%) in the ability to recognize malignant microcalcification in comparison to the established system (74.8%). The specificity (75.8 versus 71.6%) was slightly higher for the new system but these results were not statistically significant (p<0.001). Considering the diagnostic accuracy, the new system (detector: resolution 50 µm) was also slightly superior to the well-known system (detector: resolution 70 µm) (80.1% versus 76.4%). CONCLUSIONS: Our study has shown that the new full-field digital mammography system using the novel detector compared with the already established FFDM system with respect to the assessment of microcalcification is at least equivalent.

[First experiments for the detection of simulated mammographic lesions: digital full field mammography with a new detector with a double plate of pure selenium]. / Erste Untersuchungen zur Detektion simulierter mammographischer Läsionen : Digitale Vollfeldmammographie mit einem Doppelschicht-Selen-Detektor.

PURPOSE: The article describes an experimental phantom study of a system for digital full field mammography with a new digital detector with a double plate of pure selenium. MATERIALS AND METHODS: The experiments were carried out with the new full field digital mammography system Amulet from FujiFilm. This system has a new detector (18×24 cm(2)) on the basis of highly purified amorphous selenium (a-Se) with a pixel size of 50 µm. The x-rays are converted into electric signals in the first plate which are read into the second plate with the help of an optical switch and demonstrated in the form of an image. In this way a better pixel size/volume and signal-to-noise ratio should be achieved. The object of the investigation was the Wisconsin Mammographic Random Phantom, Model 152 A (Technical Performance Mo/Mo, 28 kV, 100 mAs). Five investigators with different experiences in mammography each received three images on a monitor with different random positions of the simulated lesions in the phantom for assessment. The detection rates were compared under the same conditions with the results of two other full field digital mammography systems. RESULTS: The median detection rate for all images and investigators for the new doubled plated a-Se detector with optical switch was 98.7%. For both other systems with a-Si or and a-Se detectors the detection rate was 89.8% or 97.3%, respectively. There were no significant differences in the detection rate of the simulated breast lesions for all three systems considering the interobserver and intraobserver variation. CONCLUSION: The first phantom study for the detection of simulated breast lesions with the new full field digital mammography system Amulet demonstrates equivalent results with the other systems used in the clinical routine. The trend towards superiority of the new system has to be confirmed in further clinical studies.

Digital mammography: an update.

Digital mammography has increasingly replaced conventional film-screen mammography and has become the gold standard in combination with soft copy reading in diagnostic as well as screening settings. Large international multi-center trials were able to demonstrate at least equivalence and for some aspects superiority of digital over conventional mammography with regard to detectability of breast cancer, especially in pre/perimenopausal women, women younger than 50 years and generally in dense breasts. Especially the experienced reader may benefit form CAD with an increase of specificity. Additionally digital mammography offers options of advanced processing such as digital tomosynthesis and contrast enhanced mammography. The future of breast imaging will be fusion of different imaging systems (hybrid systems).

Comparison of flat-panel-detector-based CT and multidetector-row CT in automated volumetry of pulmonary nodules using an anthropomorphic chest phantom.

This study evaluates the accuracy and reproducibility of an experimental flat-panel-detector-based CT scanner (fp-CT) in comparison with those of a 64-slice multidetector row CT (MDCT) in automated pulmonary nodule volumetry. An anthropomorphic chest phantom with 31 spherical nodules (nodule diameters of 2.94-10.01 mm; volumes of 13.24-524.97 mm(3)) was scanned both with an amorphous silicon-based fp-CT scanner, using various tube current and kilovoltage settings, and with a conventional MDCT scanner. Automated nodule volumetry was performed using dedicated software. CT image data were evaluated twice by two independent radiologists. Intra- and inter-observer variations of volumetric measurements were determined and tested using the Kruskal-Wallis test and analysis of variance (fn-ANOVA). The percentage measurement errors (PME) were calculated and differences tested using Wilcoxon signed ranks and Friedman tests. Intraobserver variation was significantly higher for MDCT than for fp-CT (range: p = 0.043-0.045). The measured nodule volumes were significantly greater on fp-CT than on MDCT scans (p<0.001). The PME was significantly greater in fp-CT than in MDCT scans (PME range, 12.35-13.35% for fp-CT scan protocols and 16.87-19.02% for MDCT scan protocols; p<0.0001). The PME increased significantly with reduction of nodule size, and this increase was significantly higher on MDCT than on fp-CT scans (p = 0.0001). The absolute PME was significantly different for nodules of less than 5 mm in diameter (p = 0.0001-0.0033) than for larger nodules. Flat-panel-detector-based CT has advantages over MDCT in accurately determining the volume of pulmonary nodules below 5 mm in diameter.

[Current situation and future perspectives of digital mammography]. / 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.

[Experimental investigations for dose reduction by optimizing the radiation quality for digital mammography with an a-Se detector]. / Experimentelle Untersuchungen zur Dosisreduktion durch Optimierung der Strahlungsqualität bei digitaler Vollfeldmammografie mit einem Detektor auf Selenbasis.

PURPOSE: Reduction of radiation exposure at an adequate image quality by optimizing the radiation quality for a new system of full-field digital mammography using a digital detector (a-Se). MATERIALS AND METHODS: The investigations were performed using a digital mammography system Novation (Siemens, Erlangen). The system was constructed with a bimetal anode (molybdenum and tungsten) and the possibility of changing the filter (molybdenum/rhodium). The test object was the Wisconsin Mammography Random Phantom Model 152 A (Radiation Measurements Inc.) of which images were acquired using the digital technique with the tungsten anode and rhodium filter at different tube voltages (26-35 kV) and tube loads (40-100 mAs) and compared to images in the molybdan/molybdan molybdenum/molybdenum technique. To quantify the image quality, we used the detection rate of the simulated lesions in the phantom. RESULTS: Increasing the tube voltage significantly decreases the average glandular dose when using AEC (Automatic Exposure Control), i. e., constant detector dose. At the same time, the image quality decreases significantly with respect to the detection rate (26 kV, 1 mGy, 95.1 %; 35 kV, 0.7 mGy, 82.7 %). As a good compromise between the necessary diagnostic image quality and the lowest dose exposition, 28 kV and 60 mAs were selected for imaging with the tungsten/rhodium anode/filter combination. A further change to the tube load did not make sense because a decrease of 10 % resulted in a significant decrease in the detection rate while only a 2 % increase in detection rate was achieved for a 65 % increase in radiation exposure. CONCLUSION: The results of this phantom study demonstrate that the routine use of the tungsten anode in combination with a rhodium filter for full-field digital mammography with an a-Se detector in contrast to a molybdan/molybdan molybdenum/molybdenum anode/filter combination results in a reduction of the average glandular dose of up to 30 % without loss of diagnostic image quality.

[Comparing the clinical value of spot view mammography with reduced pixel size to monitor zooming by reporting microcalcifications in digital mammography]. / Vergleich der klinischen Wertigkeit von Zielaufnahmen mit reduzierter Pixelgrösse des Detektors und digitalem Monitorzooming bei der Beurteilung von Mikrokalzifikationen in der digitalen Mammografie.

PURPOSE: Evaluation of the diagnostic value of breast specimen imaging with a digital mammographic system using a detector system with changeable pixel size compared to standard mode imaging in different monitor display modes. MATERIALS AND METHODS: Using the digital mammographic system SenoScan (Fischer Imaging, Denver, USA), 50 diagnostic breast specimens with microcalcifications were visualized in both standard mode (pixel size 54 microm) and high resolution mode (pixel size 27 microm). The resulting radiographs were displayed 1:1 on a monitor. Standard mode images (pixel size 54 microm) were additionally displayed in a 2:1 mode. A total of 5 readers with different mammographic experience analyzed the type of the microcalcifications on the basis of the different display modes. The images were presented randomly. The findings were subsequently compared to the histology. RESULTS: The high resolution mode yielded slightly but not significantly better results than the standard mode on average for all 5 readers. Compared to a sensitivity of 80 % and a specificity of 72 % (PPV = 74 %, NPV = 78 %) in the standard mode, the high resolution mode provided a sensitivity of 86 % and a specificity of 74 % (PPV = 77 %, NPV = 83 %). The standard mode images on a 2:1 monitor display yielded 84 % and 74 % (PPV = 76 %, NPV = 82 %). CONCLUSION: The high resolution mode did not significantly increase the sensitivity and specificity of the microcalcification reading. A similar improvement was achieved by the 2:1 display mode, i. e. digital monitor zooming. For the clinical situation this means that there is no diagnostic advantage from using a high resolution target view with this mammographic system.

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.

Applications and literature review of the BI-RADS classification.

The Breast Imaging Reporting and Data System (BI-RADS) of the American College of Radiology (ACR) is a tool created to reduce variability in the terminology used in mammographic reports. An illustration of mammographic examples from our institution interpreted according to the BI-RADS lexicon of the American College of Radiology (ACR) is presented. A literature review concerning the usefulness and limitations of the BI-RADS lexicon is given.

[Clinical results of digital mammography]. / Digitale Mammographie Klinische Ergebnisse.

Digital mammography is the technology of the future in breast diagnosis. This article provides an overview of all digital mammography units admitted by the Food and Drug Administration (FDA), results of clinical studies, soft copy reading, CAD (computer aided detection), and presents an overview on possible further developments. It is obvious that clinical results are equivalent to conventional screen film mammography and digital mammography.

[Phantom study for the detection of simulated lesions in five different digital and one conventional mammography system]. / Phantomstudie zur Detektion simulierter Läsionen an fünf verschiedenen digitalen und einem konventionellen Mammographiesystem.

PURPOSE: Experimental phantom study for the detection of simulated lesions with five different digital and one conventional screen-film mammography system. MATERIALS AND METHODS: Three radiographs were obtained at various configurations of the phantom with one conventional screen-film system (Mammomat 3000 N) (Siemens), five digital systems (high resolution computed radiography system [Fuji/Siemens], one a-Si detector [GE Medical Systems], two a-Se detectors [Siemens; Hologic / Lorad] and one CCD detector [Fischer Imaging]), applying the same exposure parameters. The Wisconsin Mammographic Random Phantom, Model 152 A, was used. Five investigators with different experience in mammography (3 months to more than 4 years) evaluated the 18 randomly selected radiographs. RESULTS: No significant differences were found in the detection rate of simulated breast lesions for conventional screen-film mammography (84.9 %), high resolution computed radiography (86.7 %) and digital mammography with an a-Si detector (89.8 %). Highly significantly better results (p < 0.001) were found with the two a-Se systems (97.3 %) and the CCD system (100 %). CONCLUSION: Conventional screen-film mammography can be replaced by high resolution computed radiography and digital mammography with a-Si-, a-Se- and CCD-detectors. This has to be confirmed in further clinical studies.

Dose reduction in full-field digital mammography: an anthropomorphic breast phantom study.

The aim of this study was to evaluate the potential for radiation dose reduction by using other beam qualities in full-field digital mammography (FFDM) compared with screen-film mammography (SFM). FFDM was performed using an amorphous silicon detector with a caesium iodide scintillator layer (Senographe 2000D, GE, Milwaukee, USA). SFM was performed using a state-of-the-art conventional system (Senographe DMR, GE, Milwaukee, USA) with a dedicated screen-film combination. An anthropomorphic breast phantom with superimposed microcalcifications (50-200 microm) was used to evaluate the detectability of microcalcifications. Contact mammograms and magnification views (m=1.8) performed with both the digital and the screen-film system were compared. Images were exposed automatically. Molybdenum/Molybdenum (Mo/Mo) anode-filter combination, 28 kVp and 63 mAs were selected by the automatic optimization of parameters (AOP) of the conventional system. This exposure protocol (protocol A) was also used as baseline for the digital system. Dose reduction in digital mammography was achieved by using protocol B with Mo/Rh and 31 kVp and protocol C with Rh/Rh and 32 kVp. The detectability of microcalcifications was assessed by 3 experienced readers with a confidence level ranging from 1 to 5. A receiver operating characteristic (ROC) analysis was performed. In protocol A the area under the ROC-curve (A(z)) for contact views performed by the screen-film system was 0.64 and for those performed with the FFDM system 0.68. The A(z) values were 0.74 in protocol B and 0.65 in protocol C for the digital system. For the conventional and digital magnification views A(z) values were 0.71 and 0.79, respectively. For protocol B the A(z) value was 0.81 and for protocol C it was 0.76. There is no statistically significant difference in the A(z) values for the different protocols in digital mammography and no significant difference from the screen-film system. A potential for dose reduction by using other beam qualities seems to be possible with this digital system.

Magnification mammography: a comparison of full-field digital mammography and screen-film mammography for the detection of simulated small masses and microcalcifications.

The objective of this study was a comparison of a full-field digital mammography (FFDM) system and a conventional screen-film mammography (SFM) system with respect to the detectability of simulated small masses and microcalcifications in the magnification mode. All images were obtained using 1.8 times magnification. The FFDM images were obtained at radiation dose levels of 1.39, 1.0, 0.7, 0.49 and 0.24 times that of the SFM images. A contrast-detail phantom was used to compare the detection of simulated lesions using a four alternative forced-choice reader study with three readers. The correct observation ratio (COR) was calculated as the fraction of correctly identified lesions to the total number of simulated lesions. Soft-copy reading was performed for all digital images. Direct magnification images acquired with the digital system showed a lower object contrast threshold than those acquired with the conventional system. For equal radiation dose, the digital system provided a significantly increased COR (0.95) compared with the screen-film system (0.82). For simulated microcalcifications, the corresponding difference was 0.90 to 0.72. The digital system allowed equal detection to screen-film at 40% of the radiation dose used for screen film. Digital magnification images are superior to screen-film magnification images for the detection of simulated small masses and microcalcifications even at a lower radiation dose.

Average glandular dose with amorphous silicon full-field digital mammography - Clinical results.

PURPOSE: Determination of average glandular dose with a full-field digital mammography system using a flat-panel X-ray detector based on amorphous silicon technology for a large group of patients. MATERIAL AND METHODS: The patient group includes women who were examined in a 4-month period with the digital mammographic system Senographe 2000D. The number of women was 591 and the number of exposures was 1116; only cranio-caudal projections were considered. Various quantities, including entrance surface air kerma, tube loading, and compressed breast thickness, were determined during actual mammography. Average glandular dose was determined using conversion factors g for standard breast composition. RESULTS: The mean average glandular dose was 1.51 mGy (0.66 - 4.05 mGy) for a single view. The mean compressed breast thickness was 55.7 mm. The mean age of patients was 55 years (34 - 81 years). CONCLUSION: The results demonstrate that full-field digital mammography with a flat-panel detector based on amorphous silicon needs about 25 % less dose in comparison with conventional screen-film mammography.

[Digital full field mammography: comparison between radiographic direct magnification and digital monitor zooming]. / Digitale Vollfeldmammographie: Vergleich zwischen radiographischer Direktvergrösserung und digitalem Monitorzooming.

PURPOSE: Our goal was to compare digital magnification mammograms with images zoomed from the digital contact mammogram in patients with microcalcifications. PATIENTS AND METHODS: Fifty-five patients with 57 microcalcification clusters were evaluated with a FFDM system (Senographe 2000D, GE). In addition to a digital contact mammogram, a digital direct magnification mammogram (factor 1.8 [MAG1.8]) and an image zoomed from the contact mammogram with a magnification factor of 1.8 [ZOOM1.8] were obtained in each patient. The image quality (perfect = 5 points to inadequate = 1 point) and the characterization of microcalcifications (BI-RADS 2-5) were evaluated by 4 readers. The results were compared to histopathologic findings in 35 patients (37 lesions) and follow-up in 20 patients. RESULTS: Histopathology revealed 16 benign and 21 malignant lesions. 20 patients had benign changes verified by long-term follow-up. Image quality of direct magnification FFDM was assessed superior (4.44 points) to zoomed images (4.14 points). Sensitivity was superior for direct magnification (97.5%) in comparison to the zoomed images (96.3%). However, specificity (MAG1.8: 34.3%, ZOOM1.8: 40%), PPV (MAG1.8: 47.5%, ZOOM1.8: 49.8%) and accuracy (MAG1.8: 58.1%, ZOOM1.8: 61.2%) were better with zooming technique. Deviation steps from best BI-RADS assessment were 0.45 for MAG1.8 and 0.44 for ZOOM1.8. CONCLUSIONS: In patients with mammographic microcalcifications, monitor zooming of the digital contact mammogram is equivalent to direct magnification FFDM. Therefore, monitor zooming allows a reduction of the radiation exposure and an optimization of the work-flow.

[Physical and technical aspects of digital mammography]. / Physikalisch-technische Aspekte der digitalen Mammographie.

The establishment of digital mammography systems constitutes a slow process, the reason for this being the general need of particular image quality in mammography. This article provides an overview of the physical basis of digital mammography with high image quality and dose as low as reasonably achievable. The trade-off of high contrast resolution and effective quantum efficiency of the imaging system on the one hand, and the demand of high spatial resolution or very small pixel size on the other hand is discussed. The actual status of the available digital detector technology for mammography is described. The digital systems presently available are superior to conventional screen-film mammographic systems with respect to contrast resolution. An outlook on possible further developments in the field of digital mammography is presented.

[Soft copy versus hard copy findings in digital mammography]. / Softcopy-versus Hardcopybefundung in der digitalen Mammographie.

The advantages of full field digital mammography are the excellent and reliable image quality and the reduction of radiation exposure. Image acquisition and display are decoupled in digital mammography allowing for optimization of both independently. Image displays are currently either hardcopy produced with a laser printer or softcopy using a computer monitor. Since the amount of data is high the hardware and software must meet specific technical specifications. The diagnostic accuracy of softcopy and hardcopy interpretation is comparable if a high resolution laser printer and a high quality workstation with high spatial and contrast resolution monitors are used. However, using film display the potential benefits of digital mammography in terms of manipulation of the data is lost. Additional diagnostic benefits might be gained by the combination of softcopy display and computer assisted diagnosis (CAD) and telemammography.

[Value and significance of digital full-field mammography within the scope of mammography screening]. / Wert und Bedeutung der digitalen Vollfeldmammographie im Rahmen eines Mammographie-Screenings.

To evaluate the digital technique for screening mammography various experimental studies and clinical examinations were performed by using direct full-field digital mammography (FFDM). The findings concerning the detectability and characterization of microcalcifications and soft tissue masses as well as the radiation exposure were compared to the state-of-the-art conventional screen-film mammography (SFM). The results of these studies revealed a high performance of the digital images, which are at least equivalent to the conventional images, whereas digital spot views were significantly superior to conventional ones particularly in the detection of microcalcifications. This was especially true, when the potential of post-processing was used. In addition, the sensitivity of FFDM should be increased, if computer-aided-diagnosis (CAD) is available. Furthermore, the patient radiation dose can be significantly reduced. Additional advantages are quick and easy handling, efficient data transfer and digital archiving. Thus, FFDM will become an important tool in screening mammography.

Dose reduction by direct-digital cephalometric radiography.

Patient radiation exposure was determined for conventional and direct-digital cephalometric radiography. An anthropomorphic phantom was positioned to expose lateral cephalographs from the patient's left side. The conventional radiographs were exposed with a Siemens Orthophos C unit (77 kV, 14 mA, 0.5 s) and a film-screen system of a relative speed of 400. The direct-digital radiographs were exposed with a Siemens Orthophos DS Ceph (73 kV, 15 mA, 15.8 s). A set of 108 thermoluminescence detectors (TLDs; Bicron STI/Harshaw, Solon, Ohio) was used for dose measurements. For each measurement, 84 TLDs were placed at the surface of the head and neck, as well as inside the phantom, at anatomically relevant positions. The remaining detectors were employed for calibration purposes and quality control. The highest absorbed doses were recorded for the conventional technique at the skin of the left parotid region (132 microGy), in the left parotid gland (103 microGy), and in the ocular lens of the left eye (81 microGy). Digital cephalometry resulted in an absorbed dose about 2 times lower than the dose received by the conventional technique. The effective doses had the same relation (conventional 2.3 microSv; digital 1.1 microSv). The results demonstrate that direct-digital cephalometric radiography cuts the patient's dose in half compared with the conventional screen-film technique. Direct-digital cephalometry is more advantageous than the conventional technique from the perspective of radiation protection.

[Dose measurements comparing conventional and digital panoramic radiography]. / Dosismessungen zum Vergleich von konventionellen und digitalen Panoramaschichtaufnahmen.

OBJECTIVE: The purpose of our study was to measure and compare patient exposure by direct digital and conventional panoramic radiography. MATERIAL AND METHODS: Dose measurements were carried out on an anthropomorphic phantom, which was specially developed for dental radiography. Panoramic radiographs were taken with three different conventional devices (Orthopantomograph 10E, Orth Oralix FD, Siemens Orthophos) and two direct digital devices (Orthopantomograph 100 Digipan, Siemens Orthophos DS Ceph). The exposure conditions were according to clinical routine. The energy dose was measured at 28 places inside and on the surface of the phantom by using a set of 108 thermoluminescence detectors. Additionally, exposure time, tube voltage, central-beam dose, and dose-area products were measured. The effective doses were calculated on the basis of the absorbed doses. RESULTS: In each case, the highest energy doses were recorded at the parotid gland, the mandibular angle, the submandibular gland, and the skin in the neck. Panoramic radiographs taken with the conventional units yielded in effective doses in the range of 16-21 microSv, the digital units caused 5 or 14 microSv. CONCLUSION: In comparison with conventional techniques, patient exposure can be reduced by direct digital panoramic radiography. The extent of dose reduction depends on the device employed and is generally smaller than the dose reduction that can be achieved by digital imaging devices in intraoral radiography.