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

European Radiology Experimental

Table. 3 Receiver operating characteristic analysis for construction of index maps

Parameter	Mean ± SD	Mean ± SD	p value	Dir	AUC	95% Confidence interval	Cutoff	Sen	Spec	Acc
	Malignant (n = 74)	Benign (n =35)
ADC	1,124 ± 180	1,692 ± 313	< 0.001	>	0.958	0.922−0.993	1,338.5	0.892	0.914	0.899
I_ADC	80 ± 21	17 ± 25	< 0.001	<	0.945	0.894−0.996	53.4	0.865	0.914	0.881
	All other (n = 86)	HAEMs (n = 23)
D′	1,076 ± 184	1,784 ± 314	< 0.001	>	0.985	0.965−1.000	1,529.4	0.988	0.913	0.972
I_D	95 ± 12	20 ± 25	< 0.001	<	0.985	0.966−1.000	51.0	0.988	0.913	0.972
	All other (n = 97)	FNHs (n = 12)
f′	63 ± 35	164 ± 58	< 0.001	>	0.968	0.938−0.998	114.5	0.907	1.000	0.917
I_f	82 ± 17	32 ± 17	< 0.001	<	0.974	0.947−1.000	54.6	0.918	1.000	0.927

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, and I_f 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, and I_f 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), FNH Focal nodular hyperplasias, HAEM Haemangioma, SD Standard deviation, Sens Sensitivity, Spec Specificity