What every surgical oncologist should know about digital mammography.

This article reviews the available information on digital mammography for surgeons who care for patients with breast cancer. The limitations of the current film-based technology and why digital mammography promises to improve breast cancer detection and breast lesion diagnosis are described. The basics of digital imaging technology are reviewed, including a description of image contrast and spatial resolution and its variance from currently available clinical digital mammography systems. The results of clinical trials completed to date are reported. An upcoming large screening trial for digital mammography, sponsored by the National Cancer Institute, is described. Future technological developments, including improvements in softcopy display, image processing, computer-aided detection and diagnosis (CADD), tomosynthesis, and digital subtraction mammography (DSM), are briefly discussed.

Perspective on digital mammography.

Digital mammography, particularly through its advanced applications, holds great promise for improved diagnostic accuracy, but the display of the images is not ideal at present. Clinical softcopy workstations are somewhat unwieldy to use, and image processing has not yet been optimized for each machine or for each clinical task. In addition, the cost-effectiveness and accuracy of the technology warrant careful study before digital mammography becomes widely disseminated and potentially replaces screen-film mammography, a technology that has been well documented to reduce breast cancer mortality.

Placental transmogrification of the lung, a histologic variant of giant bullous emphysema. Clinicopathological study of three further cases.

Placental transmogrification of the lung was described by Chesney in 1978 as an unusual cystic lesion involving a single pulmonary lobe (3). We studied three additional cases with identical clinical and pathologic features. The patients were a 33-year-old woman and men aged 24 and 27 years. Each patient was first seen with respiratory distress; one had repeated pneumothoraces. Radiographically, an enlarging cystic lesion was present in a lower (two) or middle (one) lobe. The lesion had been present for 10 years in one patient. In two patients, mediastinal shift was noted. Lobectomy was curative in all instances. Grossly there was a uni- or paucilocular cyst lined by papillary structures. Microscopically, the papillae contained proliferating blood vessels, lymphoid nodules, smooth muscle, and fat. Sclerotic foci obliterated the vessels in some areas. The growth pattern and topography resembled those of placental villi. Systematic review of the histologic features in other lungs with marked emphysema revealed a spectrum of similar changes and suggested that the lesion in our patients may be a complication of bulla formation and is most likely the clinico-pathologic analog of the "vanishing lung" syndrome (idiopathic giant bullous emphysema).

Observations of a comet on collision course with the sun.

A brilliant new comet (1979 XI: Howard-Koomen-Michels) was discovered in data from the Naval Research Laboratory's orbiting SOLWIND coronagraph. An extensive sequence of pictures, telemetered from the P78-1 satellite, shows the coma, accompanied by a bright and well-developed tail, passing through the coronagraph's field of view at afew million kilometers from the sun. Preliminary orbital calculations based on the observed motion of the comet's head and morphology of the tail indicate that this previously unreported object is a sungrazing comet and may be one of the group of Kreutz sungrazers. It appears from the data that the perihelion distance was less than 1 solar radius, so that the cometary nucleus encountered dense regions of the sun's atmosphere, was completely vaporized, and did not reappear after the time of closest approach to the sun. After this time, however, cometary debris, scattered into the ambient solar wind, caused a brightening of the corona over one solar hemisphere and to heliocentric distances of 5 to 10 solar radii.

White Light Coronagraph in OSO-7.

A small, externally occulted Lyot-type coronagraph, designed for use in the seventh unmanned Orbiting Solar Observatory (OSO-7), is described. Optical configuration, suppression of stray light, SEC vidicon detector, and data system are discussed, as well as integration of the instrument into the spacecraft and operation in orbit. Orbital operation produced daily images of the white light corona, from 2.8 to 10 solar radii, at least once per day for 2(3/4) yr. The first records of white light coronal transient events were obtained, and the corona was shown to be constantly changing.