Diagnostic accuracy of apparent diffusion coefficient to differentiate intrapancreatic accessory spleen from pancreatic neuroendocrine tumors

Table 1 Magnetic resonance imaging findings in patients with intrapancreatic accessory spleen and small hypervascular pancreatic neuroendocrine tumors

Parameters	IPAS	PNETs	P value
Lesion diameter in mm	17.71 ± 5.09	18.21 ± 5.47	0.803
Lesion ROI in cm2	0.685 ± 0.601	0.866 ± 0.567	0.413
Spleen ROI in cm2	2.134 ± 0.805	2.753 ± 0.910	0.066
Spleen ADC as × 10-3 mm2/s	0.817 ± 0.943	0.806 ± 0.145	0.825
aADC as × 10-3 mm2/s	0.931 ± 0.773	1.254 ± 0.219	< 0.001
rADC	1.154 ± 0.167	1.591 ± 0.364	< 0.001

aADC: Absolute apparent diffusion coefficient; ADC: Apparent diffusion coefficient; IPAS: Intrapancreatic accessory spleen; PNETs: Pancreatic neuroendocrine tumors; rADC: Normalized apparent diffusion coefficient (lesion-to-spleen apparent diffusion coefficient ratios); ROI: Regions of interest.

Table 2 Diagnostic performances of absolute apparent diffusion coefficient and normalized apparent diffusion coefficient values

Variables	AUC	Sensitivity, %	Specificity, %	PPV, %	NPV, %	Accuracy, %
aADC as × 10-3 mm2/s	0.94	81.25	100	100	81.25	89.66
rADC	0.91	81.25	92.31	92.86	80.00	86.21

aADC: Absolute apparent diffusion coefficient; AUC: Area under curve; NPV: Negative predictive value; PPV: Positive predictive value; rADC: Normalized apparent diffusion coefficient (lesion-to-spleen apparent diffusion coefficient ratios).