Fig. 3.
54-year-old male with lung abscess. a Axial CT image of the lung window showing a round mass in the right lower lobe. b–d Axial CT images of the mediastinal window in non-contrast-enhanced scanning (b) and arterial phase (c), and artificial color map of iodine concentration in venous phase (d) showing internal necrosis with ring enhancement. e Effective atomic number image showing that the effective atomic number for necrosis in non-contrast-enhanced scanning is 7.44. f The gradually increasing spectral curve for necrosis in non-contrast-enhanced scanning showing a K40–65 keV of − 0.43