Fig. 1

Contrast-enhanced CT image of a 47-year-old man shows a small lymph node in the right upper paratracheal. The short and long diameters are 8 mm and 10 mm in the transverse section on the preoperative CT, with an axial ratio of 0.8 (8/10) (A), this small lymph node was confirmed unresected on postoperative CT 2 months later, with a larger size of 10×12mm in the transverse section (B), and shrunk after radiotherapy with a size of 5×7 mm in the transverse section (C)