Efficiency and reporting confidence analysis of sequential dual-energy subtraction for thoracic x-ray examinations

Rationale and objectives: We aimed to report and compare accuracy, reproducibility, and reporting confidence between thoracic dual-energy subtraction (DES) and routine posterior-anterior chest radiography (PA-CR) techniques. Materials (patients) and methods: We obtained DES (D1-D4) images from 96 patients using DES and a high-resolution dynamic flat-panel detector in combination. We compared the DES images of these patients with their PA-CR images. The maximum time interval between performing DES and PA-CR was nine weeks. Two radiologists evaluated abnormal findings on DES and PA-CR images using a three-point scale, and reporting confidence was scored using a four-point scale. The intra- and interobserver agreement values of the scores were analyzed. Further, the radiation exposure doses during PA-CR and DES acquisitions were calculated. Results: The intra- and interobserver agreement values of PA-CR and DES images were good. The reporting confidence scores for DES were generally higher than those for PA-CR. Between bone-subtracted (D3) and soft-tissue-subtracted (D4) images, the former was more successful and useful in the evaluation of bone structures, whereas the latter was better in the evaluation of consolidation and/or solitary nodules. Conclusions: DES has the potential to improve the accuracy, reproducibility, and reporting confidence of thoracic radiography. It also has the potential to provide a better diagnosis of chest pathologies using relatively low dose radiation.