Efficacy of inverted digital luminescence radiography in evaluating chest neoplasms.

Inverted (positive) digital chest radiographs of patients with lung tumors were compared with commonly used (negative) digital images, consisting of one simulated normal and one contrast enhanced image. The first part of the material consisted of 80 patients of whom 40 had tumors and 40 were normal. Five radiologists with different experience reviewed the examinations. From their answers, ROC curves were constructed. The second part of the material consisted of 100 chest phantom examinations with a simulated tumor in the mediastinum (45 examinations) and/or the left lung (46 examinations). In 31 exposures there was no abnormality. These were reviewed by 3 observers and performed as an ROC study as well. There was no statistical difference between the different types of images or between the observers in the 2 studies.

Digital luminescence radiography in interstitial lung disease. A receiver operating characteristics (ROC) analysis.

The subtle changes often found in interstitial lung disease can be difficult to evaluate at conventional radiography. In order to define the information obtained with digital radiography, it is particularly important to find out to what extent interstitial lung disease can be observed with this technique. Ninety-one patients, 56 with interstitial lung disease and 35 with normal lungs, were examined both with a digital system and with conventional film-screen technique. The examinations were reviewed independently by 4 radiologists with different experience and receiver operating characteristics (ROC) curves were constructed. The 2 systems were equal in diagnostic performance with no statistic difference between the conventional radiographs, the 2 digital images reviewed together or the 2 digital images reviewed separately. There was a significant difference between the 2 observers with the highest and the one with the lowest score only in the review of digital unsharp mask images, but otherwise no differences statistically. A lower number of false negatives and a higher number of false positives were seen with the digital unsharp mask image, producing a higher sensitivity and lower specificity.

Accuracy of digital radiography using stimulable phosphor for diagnosis of pneumothorax.

To evaluate the efficacy of digitized radiography in diagnosing pneumothorax 78 patients were examined with both the conventional film-screen technique and digital radiography. Of these 78 examinations 40 were normal and in 38 a pneumothorax was found. Four observers with different experience reviewed the films. In an ROC analysis no significant differences were found between the two systems. Between the observers, however, there were slight differences, one of them showing significantly lower specificity.