Support line and tube visibility in chest examinations using computed radiography.

The visibility of support lines and tubes was compared in computed radiography (CR) and screen-film adult chest radiographs. Parameters investigated were radiation dose, image minification, and the use of unsharp mask enhancement. Five radiologists rated the visibility of support lines and tubes on a five-point scale ranging from 1 (entire course of line visible) to 5 (line not visible or only small portion seen). These CR results were compared with the visibility of support lines and tubes as assessed by the same readers for conventional screen-film radiographs (600 speed). Support line and tube visibility improved with image enhancement, image minification, and increasing radiation dose. At the same radiation exposure, support line and tube visibility of the screen-film combination was superior to that of standard CR images. Application of an unsharp mask enhancement algorithm to CR images, however, significantly improved support line and tube visibility in comparison to that obtained with the screen-film combination. It was concluded that unsharp mask processing is a valuable tool for improving the visibility of support lines and tubes in CR chest radiographs.