K.-P. Hermann

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.

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

Abstract. 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.

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.

Digitale Vollfeldmammographie: Vergleich zwischen radio-graphischer Direktvergrößerung und digitalem Monitorzooming

ZusammenfassungFragestellung. Es soll geklärt werden, ob und inwieweit das Zooming einer primär digital gewonnenen Röntgenmammographie die zusätzliche Anfertigung einer direkten Vergrößerungsmammographie entbehrlich macht. Methodik. Im Rahmen einer intraindividuellen Vergleichsstudie wurde bei 55 Patientinnen mit 57 Mikroverkalkungen die Aussagekraft der direkten Vergrößerungsmammographie (Faktor 1,8 [MAG1,8]) mit der nachträglich vom Monitorbild gezoomten Aufnahme (Faktor 1,8 [ZOOM1,8]) verglichen. Vier Auswerter stuften die Bildqualität ein und führten eine Charakterisierung der Verkalkungen nach der BI-RADS-Kategorisierung des American College of Radiology (ACR) durch. Ergebnisse. Histopathologisch fanden sich 16 benigne (sklerosierende Adenose, Hyperplasie, Hamartom, radiäre Narbe) und 21 maligne Veränderungen (DCIS, invasive Karzinome). Bei den restlichen 20 Patienten lagen gutartige Veränderungen vor, die im Verlauf über mehr als 2 Jahre befundkonstant waren. Die Bildqualität der direkten Vergrößerungsmammographie wurde besser eingeschätzt als die der gezoomten Aufnahme. Auch die Sensitivität der MAG1,8 war mit 97,5% der gezoomten Aufnahme (ZOOM1,8: 96,3%) geringfügig überlegen. Im Gegensatz hierzu zeigten die nachbearbeiteten Monitorbilder eine höhere Spezifität (MAG1,8: 34,3%, ZOOM1,8: 40%), einen besseren PPV (MAG1,8: 47,5%, ZOOM1,8: 49,8%) und eine günstigere Treffsicherheit (MAG1,8: 58,1%, ZOOM1,8: 61,2%). Die durchschnittliche Abweichung der BI-RADS-Kategorien lag bei 0,45 für MAG1,8 und bei 0,44 für ZOOM1,8. Schlussfolgerungen. Die digitale Aufnahmetechnik erlaubt aufgrund der Option des Monitorzoomings in aller Regel den Verzicht auf eine zusätzliche direkte Vergrößerungsmammographie. Hieraus resultieren eine weitere Verbesserung des Work-flows und ein Potenzial zur Dosisreduktion.AbstractPurpose. 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.

Magnification survey and spot view mammography with a new microfocus X-ray unit: detail resolution and radiation exposure

Abstract. The aim of our study was to evaluate a mammography unit capable of magnification of up to fourfold at an equivalent or lower dose than with current systems. A prototype mammography tube with an electron-beam-focusing technology resulting in a focal spot size of 40–120 μm was combined with a highly intensifying screen-film system. To evaluate contrast-detail resolution, phantom radiographs were performed with the prototype magnification mammography system using a magnification factor of 1.7 for survey views and a magnification factor of 4.0 for spot views. They were compared with unmagnified survey views and magnification spot views (magnification factor 1.9) of a state-of-the-art mammography system. The radiation exposure was measured and mean glandular doses were calculated. The contrast-detail resolution with both prototype (m = 1.7) and conventional (m = 1.1) survey views was equivalent while the entrance dose and the mean glandular dose were approximately 50 % lower with the prototype. For spot views, the contrast-detail resolution was substantially higher for the prototype than for conventional magnification while the dose was equivalent. Dose reduction and improved detail resolution are possible with this new technology.

Physikalisch-technische Aspekte der digitalen Mammographie

ZusammenfassungAufgrund der besonderen Anforderungen an die Abbildungsqualität eines Mammographiesystems vollzieht sich der Übergang zu digitalen Systemen in diesem Bereich nur zögerlich. Dieser Artikel gibt einen Überblick über die physikalisch-technischen Grundlagen für eine digitale Mammographie mit hoher Bildqualität bei möglichst niedriger Strahlenexposition. Der häufig erhobenen Forderung nach einer hohen Ortsauflösung bzw. nach einer möglichst geringen Pixelgröße wird die Kontrastauflösung und die effektive Quantenausnutzung des Abbildungssystems als maßgebliche Kenngröße der Abbildungseigenschaften gegenüber gestellt. Der gegenwärtige Stand der für die Mammographie zur Verfügung stehenden digitalen Detektortechnologie wird erläutert. Bisherige Erfahrungen zeigen, dass die auf dem Markt befindlichen digitalen Systeme bzgl. der Kontrastauflösung der konventionellen Film-Folien-Mammographie überlegen sind. Auf in der Entwicklung befindliche neue digitale Mammographiesysteme wird hingewiesen.AbstractThe 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.

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.

Dosimetry and physical treatment planning for iodine eye plaque therapy

The dosimetry of eye plaques loaded with iodine-125 seeds (type 6702) was performed by means of computer calculations and measurements with thermoluminescent dosimeters (TLD). Measurements of the depth dose distribution (2-25.5 mm) along the transverse axis of a single seed were performed in water equivalent phantom material. The transverse axis attenuation and geometry factor F(r) was obtained by applying a least squares fit to the measured data. Based on the resulting radial dose function, a computer program was developed which calculates dose distributions within the eye for arbitrary loading and placement of the eye plaque. The computational results were verified by TLD measurements in an eye phantom.

Softcopy- versus Hardcopybefundung in der digitalen Mammographie

ZusammenfassungDie Vorteile der digitalen Mammographie liegen in der exzellenten Bildqualität und hohen Bildkonstanz, in einer Reduktion der Strahlenexposition sowie in den Möglichkeiten der modernen Informationstechnologie. Durch die Entkopplung von Bildakquisition und Bilddarstellung ist eine unabhängige Optimierung dieser Teilschritte möglich. Digitale Mammogramme können entweder auf Laserfilme ausgedruckt oder am Computermonitor visualisiert werden. Dabei werden aufgrund der großen Datenmengen hohe Anforderungen an Hard- und Software gestellt. Mit hochauflösenden Laserdruckern und leistungsfähigen Workstations mit hochauflösenden Graustufenmonitoren lassen sich vergleichbare diagnostische Resultate bei der Befundung digitaler Mammogramme erzielen. Beim Filmausdruck gehen jedoch die Möglichkeiten zur interaktiven Bildbearbeitung verloren. Die weiteren Vorteile der digitalen Aufnahmetechnik wie z. B. die computerassistierte Diagnose (CAD) oder die Telemammographie können nur durch die Softcopybefundung sinnvoll erschlossen werden.AbstractThe 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 benfits might be gained by the combination of softcopy display and computer assisted diagnosis (CAD) and telemammography.

Clinical results of digital mammography

ZusammenfassungDie digitale Mammographie ist die zukunftsweisende Technologie in der Mammadiagnostik. Dieser Artikel stellt alle von der FDA (Food and Drug Administration) zugelassenen digitalen Mammographiesysteme, Ergebnisse der klinischen Studien, Monitorbefundung und CAD („computer aided detection“) vor und gibt einen Ausblick auf weitere mögliche Entwicklungen. Es wird deutlich, dass schon heute aufgrund der klinischen Ergebnisse eine Gleichwertigkeit von konventioneller Filmfolienmammographie und digitaler Mammographie gegeben ist.AbstractDigital 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.