Pulmonary nodules: detection of calcification by linear and pluridirectional movement in tomographic study

Calcification within solitary pulmonary nodules (1-2 cm range) was demonstrated by conventional tomography in a group of 20 patients. Each patient had a combined tomographic examination consisting of 15 degrees linear movement followed by 34 degrees hypocycloidal movement. Linear tomography was superior to pluridirectional tomography in 19 cases for visualization of calcium within the nodule. The results are attributed to differences in contrast sensitivity and "blur" phenomena between the two tomographic movements. This study, although comparing a specific linear movement with a specific pluridirectional movement, provides insight into the differences between tomographic techniques for a given task.