Table 3 Quantitative dual-layer spectral CT parameters from non-metastatic lymph nodes in arterial phase (contralateral axilla) and portal-venous phase (inguinal lymph nodes)

Iodine density (mg/mL)

< 0.001

 Non-metastatic contralateral

0.93 ± 0.27

 Inguinal lymph node

3.77 ± 0.14

Spectral slope

< 0.001

 Non-metastatic contralateral

0.51 ± 0.83

 Inguinal lymph node

2.36 ± 0.91

Z effective

< 0.001

 Non-metastatic contralateral

205 ± 53.8

 Inguinal lymph node

79 ± 42.7

Conventional CT HU

< 0.001

 Non-metastatic contralateral

24.4 ± 26.4

 Inguinal lymph node

69.7 ± 26.6

VNC (HU)

 Non-metastatic contralateral

9.4 ± 19.2

0.092

 Inguinal lymph node

16.8 ± 14.8

Δ contrast enhancement (HU)

< 0.001

 Non-metastatic contralateral

12.6 ± 2.2

 Inguinal lymph node

50.6 ± 1.4