The effect of varying spatial resolution on the detectability of diffuse pulmonary nodules. Assessment with digitized conventional radiographs.

Detection and discrimination of miliary disease and small pulmonary nodules were tested at six levels of spatial resolution varying between 0.3 and 2.5 l.p./mm, and receiver operating characteristic (ROC) curves were generated. The test images were obtained by digitizing selected normal and abnormal standard film/screen radiographs. Although there was no statistically significant difference in observer performance between 0.5 and 2.5 l.p./mm, the findings may have clinical relevance. Further observer detection studies of different disease processes are planned to help formulate performance standards for an electric digital radiographic device for chest imaging.

Digital radiograph of the chest using a computed tomography instrument.

Digital radiography (DR) was compared with conventional chest radiography in patients with mediastinal adenopathy, sarcoidosis, and metastatic adenocarcinoma. Contrast resolution was improved by the new technique, offering a wider latitude and edge enhancement. While small, low-contrast details were resolved best by conventional radiography, DR was superior for resolution of nodules. With further improvement of spatial and contrast resolution, DR could become the preferred technique of chest radiography.

A familial occurrence of allergic bronchopulmonary aspergillosis.

A family was recently studied in which two brothers with identical HLA serotypes had allergic bronchopulmonary aspergillosis. One of the two had a normal bronchogram. A field investigation of the family residence showed that a barn was the probable source of the organism causing disease in these patients. Immunologic characterization of the family members showed a broad spectrum of response to the environmental exposure.

Shortness of breath in emergency room patients.

There are many causes for acute shortness of breath; the most common entity by far is congestive heart failure. Many of the others have a relatively specific radiographic pattern that afford the radiologist the opportunity to make a significant contribution to the care of these patients.

Early detection of hypersensitivity pneumonitis in office workers.

Symptoms of hypersensitivity pneumonitis in three employees in an office building led to an investigation of their work environment. An open spray water air cooling system was implicated when inhalation challenge with the spray water caused acute illness in one of them. A questionnaire survey of the 4,023 co-workers identified 48 other suspect cases, and laboaratory studies confirmed hypersensitivity pneumonitis in three additional workers of this group. A significant change in pulmonary function, occurring only after exposure to the work environment, was the most useful laboratory finding and was found in five workers with no other pulmonary abnormalities, but not is asymptomatic workers or controls, since five of the six patients with hypersensitivy pneumonitis worked in offices cooled by the spray water system and since three had positive responses to inhalation challenge, use of the spray water system was discontinued. The affected workers improved after they were removed from the office complex.

An evaluation of colon cleansing regimens.

To study the efficacy of colon cleansing regimens, 500 hospital outpatients were randomly assigned to one of four regimens. Two featured castor oil followed by phosphate enema and two used magnesium citrate and bisacodyl. For the 349 patients who completed all components of the regimens, quality of the subsequent barium enema examination was scored by three radiologists in a blind manner. Regimens featuring magnesium citrate and bisacodyl were found to be significantly superior to those featuring castor oil. Calcium bisdiocytl sulfosuccinate did not improve the quality of colon cleansing but appeared to decrease the incidence of abdominal cramping in patients receiving magnesium citrate and bisacodyl. It is hoped that the investigative approach used in this study may serve as a model for future testing of colon cleansing regimens.

Interstital lung disease due to contamination of forced air systems.

Eight patients had hypersensitivity pneumonitis due to contaminated home or office forced-air heating or air-conditioning systems. We studied their clinical and laboratory features, and the results indicated that this disease may occur as an acute or insidious form differing in type and intensity of respiratory and systemic symptoms. Thermophilic actinomycetes contaminatinf the forced air systems were identified as the sensitizing agents in most cases. Precipitating antibodies to the organisms could be shown in the serums of the patients and the antigen identified by immunofluorescent studies in the three lung biopsies examined by this method. Inhalation challenge studies with the cultured organism or other materials obtained from the forced air systems reproduced the clinical syndrome in the four patients tested. Avoidance of the contaminated system, and the use of corticosteroids in more severe cases,seems to be appropriate therapy for patients with this disease.

Lymphographic demonstration of cyclic changes in lymph node size during Pel-Epstein fever.

Pel-Epstein fever cycles, consisting of 1-2 weeks of high fever separated by afebrile periods of the same duration, are classically characteristic of Hodgkin's disease. Clinical observation has determined that the lymph nodes enlarge during periods of fever and reduce in size as the fever subsides. To our knowledge, the waxing and waning of lymph nodes in tempo with the fever cycle in Hodgkin's disease have never before been documented by lymphography. The alterations we verified radiographically resemble cyclic swings in classic autoimmune diseases. Speculations are offered regarding the observed changes.

Hypersensitivity studies in popple (Aspen tree) peelers.

In the course of investigation of the relationship between hypersensitivity pneumonitis and the wood industry 45 popple peelers were studied. Four roentgenograms consistent with diffuse lung disease were found. All cases were in examinees who were also dairy farmers. Questionnaires revealed no instance of clinical symptoms of hypersensitivity pneumonitis. Gel immunodiffusion studies were positive to various antigens in eight cases, but no correlation could be made with pulmonary function or chest roentgenogram abnormalities in relation to occupation. Cultures of the wood and the surrounding environment yielded thermophilic fungi as well as other known antigenic material. It is concluded that the occupation of popple peeling does not represent an increased risk of development of hypersensitivity pneumonitis.