To evaluate the utility of dual-exposure dual-energy radiography against the standard chest radiography in the discrimination of lung nodules and the presence of nodule calcification.

Twenty-nine patients with a total of 43 peripheral lung nodules were examined by dual-exposure dual-energy radiography (DER) and confirmed by a chest CT were included in the study. Of the identified peripheral lung nodules, 24 showed calcification and 19 did not. Further, 28 lesion-free regions from the same patient population were selected as negative controls. Two radiologists evaluated 71 marked locations using both standard chest radiographs (SR) and DER to determine whether the marked locations represented a true nodule, and whether nodule calcification was present. A continuous rating scale of 0-10 was used to represent each observer's confidence level. We calculated the areas under ROC curves (AUC) for SR alone and for DER, and performed a statistical analysis to compare the results.

The ability to discriminate nodules was higher for DER than for SR. However, the was not statistically significant (p = 0.202). Inter-observer agreement was moderate regardless of if DER was used. The predictability of nodule calcification was significantly higher for DER compared to SR (p < .001). Moreover, inter-observer agreement was slight with SR alone but moderate with DER.

DER, in conjunction with SR, has no additional benefit in small lung nodule discrimination but does provide a significant benefit in the characterization of nodule calcification.