Linear vs. pluridirectional tomography of the chest: correlative radiographic anatomic study.

The basic imaging capabilities of 15 degrees linear, 30 degrees linear, hypocycloidal, and trispiral tomographic movements were compared using a fresh frozen human cadaver. Large numbers of tomograms, 100 with each tomographic movement, were compared as a motion study developed by copying the four tomographic series on movie film. In addition, the integrity of the tomograms was compared with radiographs of representative 2 mm coronal sections sawed from the fresh frozen thorax specimen. The study demonstrated the theoretical conclusion that a linear tomogram is not a sectional image and does not truthfully represent the planar anatomy of the intended layer. The pluridirectional tomograms, on the other hand, do accurately depict the anatomic section. The more general use of pluridirectional tomographic techniques in the chest is encouraged and should be used as the basis for comparing conventional tomographic imaging capabilities to other new modalities, particularly computed tomography.