Analysis of the clinical value of gemstone spectral computed tomography imaging in the preoperative assessment of colorectal cancer

Table 5 Energy spectrum parameters of metastatic and non-metastatic lymph nodes in arterial and venous phases, mean ± SD

Energy spectrum parameters		Metastatic lymph nodes (n = 150)	Non-metastatic lymph nodes (n = 115)	t	P value
IC (100 μg/cm3)	Arterial phase	15.71 ± 5.92	27.00 ± 8.89	12.383	< 0.001
	Venous phase	20.90 ± 8.59	33.93 ± 12.05	10.272	< 0.001
NIC	Arterial phase	0.16 ± 0.07	0.28 ± 0.11	10.810	< 0.001
	Venous phase	0.44 ± 0.20	0.48 ± 0.14	1.828	0.069
λHU	Arterial phase	2.20 ± 0.68	3.41 ± 1.25	10.073	< 0.001
	Venous phase	2.40 ± 1.05	3.23 ± 1.13	6.170	< 0.001

IC: Iodine concentration; NIC: Normalized iodine concentration; λ_HU: The slope of the spectral curve.