Table 4.

Area under the curve analysis of 40kev∼140kev single energy CT values in arterial phase of colorectal cancer with different microvessel densities

Single energy level/kev	AUC(95% CI)	Threshold/HU	Sensitivity/%	Specificity/%	Youden index
40	0.985(0.929–0.999)	174.91	90.00	98.08	0.8808
50	0.963(0.896–0.992)	121.56	90.00	92.31	0.8231
60	0.985(0.929–0.999)	95.12	93.33	94.23	0.8756
70	0.976(0.915–0.997)	74.81	96.67	90.38	0.8705
80	0.952(0.881–0.987)	65.56	90.00	88.46	0.7846
90	0.893(0.805–0.950)	57.91	86.67	78.85	0.6551
100	0.873(0.782–0.937)	55.09	80.00	86.54	0.6654
110	0.815(0.714–0.892)	50.38	80.00	76.92	0.5692
120	0.805(0.702–0.884)	47.81	80.00	75.00	0.5500
130	0.787(0.682–0.870)	46.18	80.00	75.00	0.5500
140	0.745(0.637–0.835)	43.50	76.67	69.23	0.4590