Quantitative parameters in novel spectral computed tomography: Assessment of Ki-67 expression in patients with gastric adenocarcinoma

Table 2 Correlation between spectral parameters and Ki-67 status

Parameters		Ki-67 status
		r (95%CI)	P value
AP	CT40 kev	-0.162 (-0.362, 0.043)	0.093
	CT70 kev	-0.097 (-0.290, 0.102)	0.316
	CT100 kev	-0.074 (-0.277, 0.117)	0.449
	λHU	-0.137 (-0.328, 0.056)	0.156
	Zeff	-0.427 (-0.606, -0.208)	< 0.001
	nZeff	-0.487 (-0.649, -0.318)	< 0.001
	IC	0.409 (0.228, 0.567)	< 0.001
	nIC	0.449 (0.288, 0.598)	< 0.001
VP	CT40 kev	-0.213 (-0.397, -0.005)	0.027
	CT70 kev	-0.216 (-0.407, -0.004)	0.025
	CT100 kev	-0.266 (-0.438, -0.096)	0.005
	λHU	-0.090 (-0.278, 0.093)	0.354
	Zeff	-0.455 (-0.647, -0.215)	< 0.001
	nZeff	-0.555 (-0.692, -0.403)	< 0.001
	IC	0.405 (0.223, 0.571)	< 0.001
	nIC	0.502 (0.355, 0.651)	< 0.001

Z^eff_AP and Z^eff_VP: The effective atomic number in the arterial and venous phase; nZ^eff_AP and nZ^eff_VP: The normalized effective atomic number in the arterial and venous phase; IC_AP and IC_VP: The iodine concentration in the arterial and venous phase; nIC_AP and nIC_AP: The normalized iodine concentration in the arterial and venous phase; CT_{40 kev,} CT_{70 kev} and CT_{100 kev}: The computed tomography attenuation value of 40 kilo electron volt (kev), 70 kev and 100 kev monochromatic images; λ_HU: The slope of the spectral curve; HU: Hounsfield unit; AP: Arterial phase; VP: Venous phase; 95%CI: 95% confidence interval.