Table 2.

Correlation of Dual-energy CT Quantitative Parameters with Immunohistochemical Biomarkers

Parameters	ER		p value	PR		p value	HER2		p value	Ki67		p value
	Positive	Negative		Positive	Negative		Positive	Negative		High-proliferation	Low-proliferation
Arterial phase NIC	0.109 ± 0.067	0.133 ± 0.055	0.069	0.101 ± 0.063	0.128 ± 0.064	0.022	0.114 ± 0.058	0.117 ± 0.069	0.850	0.130 ± 0.063	0.096 ± 0.064	0.005
Venous phase NIC	0.336 ± 0.143	0.411 ± 0.133	0.003	0.317 ± 0.138	0.388 ± 0.133	0.005	0.381 ± 0.120	0.342 ± 0.149	0.138	0.409 ± 0.129	0.283 ± 0.120	<0.001
Arterial phase nZeff	0.72 ± 0.04	0.73 ± 0.04	0.164	0.72 ± 0.03	0.73 ± 0.04	0.437	0.73 ± 0.03	0.72 ± 0.05	0.077	0.74 ± 0.03	0.71 ± 0.05	<0.001
Venous phase nZeff	0.86 ± 0.06	0.88 ± 0.03	0.011	0.86 ± 0.06	0.87 ± 0.04	0.425	0.88 ± 0.03	0.86 ± 0.06	0.022	0.88 ± 0.04	0.85 ± 0.06	<0.001
Arterial phase λHu (HU/keV)	1.71 ± 0.84	1.94 ± 0.88	0.181	1.64 ± 0.85	1.88 ± 0.84	0.127	1.86 ± 0.76	1.72 ± 0.90	0.358	1.87 ± 0.96	1.64 ± 0.67	0.129
Venous phase λHu (HU/keV)	2.63 ± 0.98	2.75 ± 1.01	0.567	2.64 ± 0.85	2.68 ± 0.98	0.848	2.79 ± 0.95	2.58 ± 1.01	0.252	2.72 ± 1.10	2.58 ± 0.81	0.421

Note—NIC normalized iodine concentration; nZ_eff normalized effective atomic number; λ_Hu slope of the spectral Hounsfield unit curve; HU hounsfield unit; ER estrogen receptor; PR progesterone receptor; HER2 human epidermal growth factor receptor 2