Comparison of chest dual-energy subtraction digital tomosynthesis imaging and dual-energy subtraction radiography to detect simulated pulmonary nodules with and without calcifications a phantom study.

RATIONALE AND OBJECTIVES

To compare the effectiveness of chest dual-energy subtraction digital tomosynthesis (DES-DT) imaging with that of DES radiography for detecting simulated pulmonary nodules with and without calcifications.

MATERIALS AND METHODS

A DES-DT and DES radiography system (SonialVision Safire II, Shimadzu Co, Kyoto, Japan) with pulsed x-rays and rapid kV switching was used to detect simulated pulmonary nodules (5 and 7 mmφ, ground-glass opacity). Low-voltage (60 kVp), high-voltage (120 kVp), and soft-tissue or bone-subtracted tomograms of the desired layer thicknesses were reconstructed from the image data acquired during a single tomographic scan using a three-dimensional filtered back-projection algorithm, bone- and soft tissue‑subtracted images, and a scan angle of 40°. In the analysis, we considered the signal-to-noise ratio (SNR) computed for various sizes and degree of calcification of the simulated pulmonary nodules. We examined 30 samples with and 30 samples without different degrees of simulated pulmonary nodules by both DES radiography and DES-DT imaging. Based on the evaluations of five thoracic radiologists, receiver operating characteristic curves were compared to assess the detection accuracy of the two methods.

RESULTS

SNR and quality of images obtained by DES-DT imaging were significantly superior to those obtained by DES radiography. Based on the results of the ROC analysis, the detection accuracy of DES-DT was significantly greater than that of DES radiography (7 mmφ without calcification P < .03; with calcification P < .003).

CONCLUSION

DES-DT imaging exhibited greater sensitivity than DES radiography for detecting simulated nodules, especially large nodules, with and without calcifications.