Real-time elastography and contrast-enhanced ultrasound for the assessment of thyroid nodules

Work-up of thyroid nodules remains challenging. Recent technologies enable determination of tissue elasticity and perfusion using ultrasound devices. The aim of the present study was to evaluate real-time elastography (RTE) and contrast-enhanced ultrasound with Sonovue (CEUS) for the differentiation of benign and malignant thyroid nodules.

Inclusion criteria were: nodules ≥1 cm, non-functioning or hypo-functioning on radionuclide scanning, and cytological/histological assessment. All patients received conventional ultrasound, RTE and CEUS. RTE was classified as: Elasticity-Score (ES)1 = soft, ES2 = predominantly soft, ES3 = predominantly hard, ES4 = hard nodule. CEUS-video clips were digitally recorded and analyzed using time-intensity-curves within selected regions-of-interest.

Fifty-three nodules in 50 patients were available for analysis. Forty-six nodules were benign on cytology/histology, 6 nodules were papillary carcinoma and one nodule was a follicular carcinoma. Nodule margin irregularity was the ultrasound pattern most predictive of malignancy with sensitivity 57% (95% confidence interval: 18-90%) and specificity 85% (71-94% p<0.05). When using ES3&4 for the diagnosis of malignant nodules sensitivity and specificity were 86% (42-99.7%) and 87% (75-95%), respectively (p = 0.0003). The only malignant nodule missed with RTE was a follicular carcinoma. Sensitivity for the diagnosis of papillary carcinoma therefore was 100%. No specific CEUS pattern could be identified to differentiate between benign and malignant nodules.

RTE seems to be a useful tool in the work-up of thyroid nodules to exclude papillary thyroid cancer. However, follicular carcinoma remains a challenging problem. CEUS did not improve the characterization of thyroid nodules in this preliminary study.