Chest radiography with a shaped filter at 140 kVp: its diagnostic accuracy compared with that of standard radiographs

The effectiveness of a shaped filter in the detection of mediastinal and retrocardiac abnormalities on 140-kVp posteroanterior chest radiographs was measured by observer-performance testing. A set of 100 radiographs (the filtered and nonfiltered radiographs of 50 patients) were randomly selected from 1000 radiographs obtained from 500 outpatients or hospitalized patients. Five observers independently interpreted the set of radiographs, with one observer interpreting the set twice. Observer performance in detecting abnormalities in the mediastinum and the retrocardiac lung were analyzed by using receiver-operating characteristic techniques. The results indicate that the use of a filter has no significant overall diagnostic advantage (areas under the receiver-operating characteristic curves were 0.90 for the filtered radiographs and 0.89 for the unfiltered radiographs). No significant differences were found in the analysis of the various types or locations of lesions in the mediastinum.