Acquired tracheomalacia: etiology and differential diagnosis.

The noninvasive diagnosis of impaired mechanical integrity or compliance of the trachea is most accurately made by fluoroscopic observation recorded on video tape or cineradiography, with or without benefit of artificial contrast media (contrast tracheography). In particular, localized buckling, collapse or dilatation indicative of focal tracheomalacia may thus be diagnosed in vivo and correlated with diseases of the central airways. Congenital tracheomalacia is a rare, bu, well described entity. Cases of acquired tracheomalacia occur with increasing frequency, but are often not clearly recognized. We contrast the dynamic behavior of the normal trachea with the abnormal dynamics characteristic of focal tracheomalacia. Such lesions may result from trauma, surgical procedures, chronic irritation, inflammation, mechanical changes, or malignancy.

Extra- and intrasplenic artery aneurysms in portal hypertension.

Extra- and intrasplenic arterial aneurysms have occasionally been encountered in cases of portal hypertension both with and without cirrhosis. The exact pathogenesis is speculative; however, it is postulated that hyperkinetic splenic circulation, probably related to hepatic arterial insufficiency or hypoplasia, constitutes the primary pathogenic mechanism. Other factors such as splenomegaly and hormonal influence may be contributory.

Asbestosis among electricians.

In a cross-sectional study of a small group of non-shipyard electricians, the prevalence of asbestosis, defined as irregular opacities of at least 1/0 profusion, was found to be 15% overall and 25% after 20 years of service. Irregular opacities occurred more frequently among smokers. Cost estimates for asbestos-related disease should include construction electricians in the populations at risk.

Storage phosphor radiographs vs conventional films: interpreters' perceptions of diagnostic quality.

We compared storage phosphor images with high-quality conventional film-screen images by evaluating physicians' perceptions of image quality and their levels of confidence in making diagnostic interpretations. Eight physicians each examined 11 posteroanterior storage phosphor chest images (obtained with an experimental high-resolution storage phosphor system) side by side with conventional film images of the same patients. The storage phosphor images were obtained only minutes after the conventional radiographs were obtained. Storage phosphor images were digitally printed onto films in two different formats: a full-size (12 X 14 in. [30.5 X 35.6 cm]) and a half-size format of four computer-processed, minified images (6 X 7 in. [15.2 X 17.8 cm] each). Most of the responses rated the quality and resolution/sharpness of conventional images, as well as their ability to display the complete lung field, as either "excellent" or "good"; however, the storage phosphor images received significantly better ratings (p less than .05). Computer-processed minified versions of the storage phosphor images also received better ratings than did the conventional images. When the physicians were asked to rate their confidence level in making diagnoses with each of the two techniques, in 74 of 88 cases they indicated that their level of confidence would be at least as high when using the storage phosphor images as when using the conventional images.

Subjective and objective assessment of image quality--a comparison.

Forced-choice just noticeable difference (JND) studies are extremely sensitive to image quality variations that are below the threshold at which the differences are apparent to or definable by the observer. Paired comparisons of 4K and 2K laser-printed posteroanterior chest images consistently demonstrated that although images are viewed as comparable by radiologists, when forced to choose the better ("sharper") image, they actually select the higher-resolution images in 83% of the paired observations. We conclude that small differences in image quality may be detectable even in image sets which are considered to be comparable by subjective assessments.

Digital radiography and conventional imaging of the chest: a comparison of observer performance.

OBJECTIVE: The purpose of this study was to compare observer performance in interpreting high-quality, digitally acquired computed radiographs of the chest displayed on either laser-printed radiographs or a workstation with observer performance in interpreting conventional chest radiographs. SUBJECTS AND METHODS: We performed a receiver-operating-characteristic study in which the presence or absence of five abnormalities was determined by nine experienced radiologists on 310 posteroanterior radiographs of the chest displayed in three forms: conventional radiographs, laser-printed films of digital radiographs, and digital radiographs on a high-resolution workstation. RESULTS: The results of our study suggest that observer performance with laser-printed films of digital radiographs obtained with high-resolution (4K x 5K), high-contrast sensitivity (12 bits) and appropriate exposure is comparable to observer performance with conventional radiographs. Observer performance with digital radiographs displayed on the workstation was found to be significantly lower for abnormalities that contained high-frequency and low-contrast information (e.g., interstitial disease and pneumothorax). CONCLUSION: Computed radiography technology can produce image quality that is adequate for interpreting posteroanterior radiographs of the chest. Observer performance is not as good when radiographs displayed on workstations are used to diagnose specific abnormalities.