Value of enhanced dual-source CT for differentiating pre-invasive lesion from invasive pulmonary adenocarcinoma appearing as pure ground-glass nodule

Objective: To assess value of contrast-enhanced dual-source dual-energy CT (CEDECT) and three-planar measurement of pure ground glass nodules (pGGN) in differentiating pre-invasive lesion from invasive pulmonary adenocarcinoma. Methods: CEDECT of 42 pGGN in 32 patients with pathologically confirmed pre-invasive lesions and invasive pulmonary adeno-carcinoma was analyzed. The CT features, three-planar measurements, average unenhanced CT values, iodine concentrations (IC) and normalized iodine concentrations (NIC) of the two groups were compared using the receiver operating characteristic (ROC) curve to evaluate the diagnostic efficacy. Results: There were significant differences in lobulation, maximum diameters, average unenhanced CT values, and average NIC between pre-invasive lesions and invasive pulmonary adenocarcinomas (P < 0.05). There were no significant differences in lesion locations, spiculations, air bronchogram, cavitation, pleural retraction and average IC between the two groups (P > 0.05). The areas under the ROC curves of maximum diameters, average unenhanced CT values and average NIC were 0.699, 0.778, and 0.930, respectively. The average NIC though three-planar measurements were more accurate than axial position measurement. Conclusion: CEDECT and three-planar measurement allow accurate calculation of the NIC of pGGN, which help to differentiate pre-invasive lesion from invasive pulmonary adenocarcinoma. (authors)