Intravoxel incoherent motion diffusion-weighted magnetic resonance imaging for predicting histological grade of hepatocellular carcinoma: Comparison with conventional diffusion-weighted imaging

Table 2 Diagnostic value of intravoxel incoherent motion diffusion-weighted imaging and conventional diffusion-weighted imaging parameters in differentiating the low-grade group (G1) from the high-grade groups (G2 and G3)

Parameter	Observer	AUC (95%CI)	Optimal cutoff value	Youden index	Sensitivity (%)	Specificity (%)	Accuracy (%)
ADC	R1	0.843 (0.718, 0.968)	1.285	0.619	78.6(11/14)	83.3(40/48)	82.3(51/62)
	R2	0.852 (0.730, 0.974)	1.275	0.649	85.7(12/14)	79.2(38/48)	80.6(50/62)
D	R1	0.909 (0.834, 0.985)	0.962	0.741	92.9(13/14)	81.3(39/48)	83.9(52/62)
	R2	0.911 (0.832, 0.990)	0.977	0.804	92.9(13/14)	87.5(42/48)	88.7(55/62)
D*	R1	0.632 (0.489, 0.776)	17.75	0.378	85.7(12/14)	52.1(25/48)	59.7(37/62)
	R2	0.636 (0.495, 0.777)	17.90	0.378	85.7(12/14)	52.1(25/48)	59.7(37/62)
f	R1	0.523 (0.348, 0.698)	0.216	0.182	78.6(11/14)	39.6(19/48)	48.4(30/62)
	R2	0.518 (0.332, 0.704)	0.246	0.173	71.4(10/14)	45.8(22/48)	51.6(32/62)

R1: Radiologist 1; R2: Radiologist 2; ADC: Apparent diffusion coefficient; D: Pure diffusion coefficient; D*: Pseudo-diffusion coefficient; f: Perfusion fraction. ADC, D, and D* are in units of × 10^-3 mm²/s; f is in units of 100%; 95%CI: 95% confidence intervals.