Use of oblique chest roentgenograms in detecting pleural disease in asbestos-exposed workers

Oblique chest roentgenograms have been recommended by some for use in screening programs of asbestos-exposed workers to increase detection of pleural fibrosis not evident on posteroanterior (PA) films. As a screening test, identification of pleural abnormalities with oblique films is especially important in subjects without evidence of other asbestos-induced abnormalities on PA films, namely, parenchymal fibrosis. To evaluate the incremental value of oblique films in the identification of pleural fibrosis, a comparison was made between PA films read alone and PA films read with both oblique views in a systematic evaluation of 489 male pipefitters examined in a screening program. Analysis of the subsets of pipefitters with and without parenchymal fibrosis showed that 2.5% of workers with normal PA films (n = 326) and 13.0% of subjects with isolated parenchymal fibrosis on PA films (n = 46) had pleural fibrosis detectable only on oblique films. In only eight (1.6%) did the oblique view represent the sole evidence of an asbestos-related roentgenographic abnormality. We conclude that oblique films should not be routinely used in screening workers for evidence of asbestos-induced disease.