Real-time ultrasound elastography - a new tool for diagnosing thyroid nodules

Real-time elastography (RTE) is a non-invasive ultrasound method of estimation of tissue stiffness by measuring the degree of local tissue displacements after a small compression. Recent data has shown its ability to differentiate benign from malignant tumours. The aim of this study was to evaluate the accuracy of RTE in the diagnosis of malignant and benign thyroid nodules.

71 thyroid nodules in 52 patients: 42 females and 10 males aged 28-77 were examined using conventional ultrasonography (US), fine-flow CD imaging and RTE. All nodules previously underwent fine-needle aspiration biopsy (FNAB), and patients with malignant and suspicious cytological results were referred for surgery. The final diagnosis was based on FNAB results in patients with benign cytology and on the histopathology reading in those who underwent surgery. An elasticity score (ES) from 1 to 5 was determined for each nodule according to the Ueno classification.

An elasticity score (ES) of 4 or 5 was found in 19 out of 22 (86.5%) thyroid cancers and in only 1 out of 31 (3%) benign nodules. This was strongly indicative for malignancy (p 〈 0.0001) with sensitivity 86%, specificity 97%, positive predictive value (PPV) 95% and negative predictive value (NPV) 91%.

RTE is a highly sensitive and specific method of diagnosing thyroid nodules. This technique can be employed in selecting thyroid nodules for fine-needle aspiration biopsy.