Simplified intravoxel incoherent motion diffusion-weighted MRI of liver lesions: feasibility of combined two-colour index maps

European Radiology Experimental

Table. 4 Receiver operating characteristic analysis for differentiation of malignant from benign liver lesions

Parameter	Malignant (n = 74) Mean ± SD	Benign (n = 35) Mean ± SD	p value	Dir	AUC	95% Confidence interval	Cutoff	Sen	Spec	Acc
ADC	1,124 ± 180	1,692 ± 313	< 0.001	>	0.958	0.922−0.993	1,338.5	0.892	0.914	0.899
D′	1,057 ± 188	1,580 ± 387	< 0.001	>	0.902	0.842−0.962	1,173.6	0.757	0.886	0.798
f′	63 ± 31	97 ± 70	0.010	>	0.622	0.491−0.754	114.5	0.932	0.457	0.780
I_ADC	80 ± 21	17 ± 25	< 0.001	<	0.945	0.894−0.996	53.4	0.865	0.914	0.881
I_D	94 ± 12	47 ± 43	< 0.001	<	0.782	0.672−0.891	51.0	0.986	0.600	0.862
I_f	81 ± 16	65 ± 30	0.032	<	0.627	0.499−0.756	57.0	0.905	0.457	0.761
I_Df	76 ± 17	20 ± 18	< 0.001	<	0.975	0.950−1.000	50.2	0.932	0.943	0.936

Mean values and standard deviations of apparent diffusion coefficient (ADC), estimated diffusion coefficient (D′), estimated perfusion fraction (f′), and index maps I_ADC, I_D, I_f and combined I_Df are presented. The optimal cutoff point of ROC analysis was selected according to maximum Youden index. ADC and D′ values are given in units of 10^-6 mm²/s, f′ values are given in units of 10^-3, and I_ADC, I_D, I_f, and I_Df are given as percentages. Acc Accuracy, ADC Apparent diffusion coefficient, AUC Area under the curve, Dir Test direction (">"/"<" means that a lower/higher test result indicates a more positive test), SD Standard deviation, Sens Sensitivity, Spec Specificity