Diagnostic efficacy of diffusion-weighted imaging and semiquantitative and quantitative dynamic contrast-enhanced magnetic resonance imaging in salivary gland tumors

Table 5 Comparison of pleomorphic adenomas, Warthin’s tumors, and malignant salivary gland tumors by ROC analysis using ADC, T_peak, K_trans, K_ep, and V_e values

Variable	Cut-off	AUC (95% CI)	Sensitivity	Specificity	PPV	NPV	P value
Pleomorphic adenomas
ADC value	> 1.1	0.977 (0.911-0.998)	1.000	0.898	0.700	1.000	< 0.001
Tpeak	> 120	0.947 (0.868-0.986)	1.000	0.898	0.700	1.000	< 0.001
Ktrans	≤ 0.46	0.702 (0.584-0.804)	0.857	0.627	0.353	0.949	0.005
Kep	≤ 1.14	0.926 (0.840-0.974)	0.929	0.831	0.565	0.980	< 0.001
Ve	≥ 0.4	0.849 (0.746-0.922)	0.929	0.729	0.448	0.977	< 0.001
Warthin’s tumors
ADC value	≤ 0.8	0.742 (0.626-0.837)	0.944	0.582	0.425	0.970	< 0.001
Tpeak	≤ 19.1	0.869 (0.769-0.936)	0.667	0.909	0.706	0.893	< 0.001
WR	> 43	0.981 (0.917-0.999)	0.944	0.909	0.773	0.980	< 0.001
Ktrans	> 0.3	0.577 (0.455-0.692)	0.889	0.346	0.308	0.905	0.291
Kep	> 2.44	0.973 (0.905-0.997)	1.000	0.855	0.692	1.000	< 0.001
Ve	≤ 0.17	0.958 (0.883-0.991)	1.000	0.909	0.783	1.000	< 0.001
Malignant tumors
ADC value	> 0.7	0.541 (0.420-0.658)	0.783	0.440	0.391	0.815	0.569
Tpeak	≤ 120	0.531 (0.410-0.649)	0.913	0.360	0.396	0.900	0.648
WR	≤ 49	0.562 (0.441-0.678)	1.000	0.300	0.397	1.000	0.351
Ktrans	> 0.53	0.599 (0.477-0.712)	0.652	0.600	0.429	0.789	0.194
Kep	≤ 3.7	0.592 (0.471-0.706)	1.000	0.300	0.397	1.000	0.160
Ve	> 0.35	0.702 (0.584-0.804)	0.696	0.660	0.485	0.825	0.001

ADC (× 10⁻³ mm²/s): Apparent diffusion coefficient; T_peak (s): Time to peak; K_trans (min⁻¹): Volume transfer constant between blood plasma and the extracellular extravascular space; K_ep (min⁻¹): Flux rate constant between the EES and plasma; V_e: EES fractional volume; AUC: Area under the ROC curve; CI: Confidence interval; PPV: Positive predictive value; NPV: Negative predictive value; WR (%): Washout ratio; EES: Extracellular extravascular space.