Fig. 1.

Diagram of three-material decomposition of voxel used by dual-energy software. This software splits every voxel in 80- and 140-kV image pair into three components represented by air, soft tissue, and iodine (for ground-glass nodule) or fat, soft tissue, and iodine (for solid nodule or lymph node). (a), (b), (c), and (d) are fixed points of CT attenuation values from two different energies for air, fat, soft tissue, and iodine, respectively. Intercept x or y along iodine axis represents iodine content of voxel on this two-energy plot. Virtual unenhanced images display noniodine component of voxel, and iodine-enhanced images display z intercept (i.e., iodine content). CGN = ground-glass opacity nodule