Visibility of bronchial arteries using virtual and advanced virtual monoenergetic imaging

Abstract

Background The utility of virtual monoenergetic imaging (VMI) for fine arteries has not been well clarified. Purpose To assess bronchial artery visualization using VMI and noise-optimized advanced VMI (VMI+). Material and Methods Eighty-seven patients with esophageal cancer underwent computed tomography (CT) using a third-generation dual-source system before surgery. Tube voltages were set to 90 kVp and 150 kVp, respectively. Images were reconstructed using VMI and VMI+ with energy levels of 40–120 keV (in 10-keV increments); composite images equivalent to CT images at 105 kVp were also generated. The CT attenuation value and contrast-to-noise ratio (CNR) of bronchial arteries using VMI and VMI+ were compared with those obtained using composite imaging. Two radiologists subjectively analyzed bronchial artery visualization with reference to the composite image. Results CT attenuation values for bronchial arteries using VMI at 40–60 keV and VMI+ at 40 keV and 50 keV were significantly higher than those obtained using composite imaging ( P < 0.05). CNR using VMI at 40–60 keV was significantly higher than that obtained using composite imaging ( P < 0.05), whereas no differences were noted for values obtained using composite imaging between VMI+ at 40 keV and 50 keV. In the subjective analysis, VMI at 40 keV and 50 keV yielded significantly better visibility of bronchial arteries than VMI+ ( P < 0.05). Conclusion VMI and VMI+ at low voltages (40–50 keV) may be useful for bronchial artery visualization. VMI+ may be less effective for fine vessels as bronchial artery visualization.