Fig. 1

a shows a female patient aged 58 with a solid nodule in the lower lobe of the left lung, as seen on CT scan with a maximum diameter of 2.4 cm (indicated by the white arrow). The nodule has a CTR of 1. Similarly, in b, a male patient aged 61 is shown to have a partially solid nodule in the upper lobe of the right lung, with a solid component size of 0.6 cm (indicated by the white arrowhead) and a maximum diameter of 1.3 cm (indicated by the white arrow). The CTR for this lesion is 0.6/1.3 = 0.46