Prospective evaluation of Quasistatic Ultrasound Elastography (USE) compared with Baseline US for parotid gland lesions: preliminary results of elasticity contrast index (ECI) evaluation.

Aims: To assess the diagnostic value of elasticity contrast index (ECI) elastography, in comparison with conventional ultrasound for the differentiation of benign and malignant parotid lesions. Material and methods: Sixty-three consecutive patients with parotid gland tumors, treated surgically at a single tertiary center were enrolled. Ultrasound evaluation consisted of B-mode, color-Doppler and quasistatic ultrasound elastography (USE), conducted with the ECI technique. For each lesion the echogenicity, margins, vascularization, and capsulation were considered to determine benign or malignant lesions. Histology was considered the gold standard. Results: Using conventional parameters, the observer suggested malignant lesions in 20 cases and benign lesions in 43 cases (accuracy: 61.8%). ECI>3.5 alone was the most accurate parameter (accuracy: 90.5%), with sensitivity of 93.7% and specificity of 89.4%. However, when combined with the other US criteria, no statistically significant diagnostic accuracy improvement was achieved. Conclusions: Our results show that USE with ECI index measurement can help to discriminate preoperatively benign from malignant lesions, with the exception of pleomorphic adenoma which is stiff. We suggest that USE can be used as an additional tool to conventional US evaluation of salivary gland lesions.