Comparison of Chest Dual-Energy Subtraction Digital Tomosynthesis and Conventional Digital Tomosynthesis for the Detection of Simulated Pulmonary Nodules with Calcifications: Phantom Study

To compare the effectiveness of chest dual-energy subtraction digital tomosynthesis (DES-DT) with that of conventional digital tomosynthesis for the detection of calcifications superimposed over simulated pulmonary nodules. A DES-DT system with pulsed X-rays and rapid kV switching was used to examine calcifications in simulated pulmonary nodules. Low-voltage, high-voltage, and soft-tissue or bone-subtracted tomograms of the desired layer thicknesses were reconstructed from the image data acquired during a single tomographic scan, bone-subtracted images, and a scan angle of 40°. Our analysis took into account the signal-to-noise ratio (SNR) of the different degrees of calcification in the simulated pulmonary nodules. For DES-DT, the SNR for the simulated pulmonary nodules increased about 63%. Based on the results of receiver operating characteristic performance analysis, the detection ability of our DES-DT was significantly better than that of conventional digital tomosynthesis (P < 0.03). The study results confirmed with a further study to assess influence of reconstruction and filtering for detection of simulated nodules. DES-DT provided greater sensitivity than conventional digital tomosynthesis.