The detection of foreign bodies in soft tissue--comparison of conventional and digital radiography.

The vast majority of glass and metallic foreign bodies can be detected with conventional radiography. The visibility of common woods and plastics is, however, unknown. To assess their radiographic visibility, various woods and plastics of equal size were inserted into fresh porcine tissue. The pork was then radiographed, under identical conditions, using conventional film-screen combination and a FUJI computed radiographic system utilizing its edge-enhancement facility. The visibility of the compounds was scored by four radiologists for both systems at various times post-insertion. Plastics were found to vary widely in visibility. Dried timbers were visible initially but became isodense with time due to absorption of fluid from surrounding tissues. Fresh woods were invisible from the outset. The computed radiographs improved the visibility of objects visible with conventional radiography but did not bring about visualization of those invisible to normal film-screen combinations. In conclusion the visibility of woods and plastics is variable. Some improvement in visibility can be brought about by the use of digitally edge-enhanced computed radiographs.