Table 4 Diagnostic performance of SE, CEUS, and combination of SE and CEUS for distinguishing between benign and malignant parotid tumors.

Features	AUC (95% CI)	Accuracy, %	Sensitivity, %	Specificity, %	PPV, %	NPV, %	P-value
SE: elasticity score>3; CEUS: >1 suspicious CEUS features; SE+CEUS: elasticity score>3 and/or >1 suspicious CEUS features. SE: strain elastography; CEUS: contrast-enhanced ultrasound; AUC: area under the receiver operating characteristic curve; CI: confidence interval; PPV: positive predictive value; NPV: negative predictive value
SE	0.75 (0.66–0.85)	79.1	60.5	90.1	78.8	79.3	<0.001
CEUS	0.82 (0.73–0.91)	84.3	72.1	91.7	83.7	84.6	<0.001
SE+CEUS	0.88 (0.80–0.95)	87.8	86.0	88.9	82.2	91.4	<0.001