Background and objective: One of the key features of thyroid gland cancer evaluated at palpation is the degree of firmness: malignant lesions tend to be much harder than benign ones. US elastography is combining the diagnostic advantages of high-frequency US examination and the accuracy of thyroid cancer diagnosis based on the lesions stiffness. The aim of our prospective study was to evaluate the elastographic appearance of thyroid gland tumours and to explore the sensitivity and specificity of US elastography for differential diagnosis of thyroid cancer, with histopathologic analysis as a reference standard.
Materials and methods: A total of 34 patients (2 male and 33 females; 48.8±13.71 years) were included in the study, presenting one or several suspicious thyroid nodules diagnosed by sonography. Local Ethical Committee approval has been obtained concerning the design of the study. Elastography was performed by the same examiner with the same settings of the machine. The nodules were classified in five classes of tissue stiffness (class 1 for soft nodules, class 2 and 3 for intermediate inhomogeneous stiffness and class 4 and 5 for hard, homogenous nodules) similar to the classical score established for the breast nodules. All the patients were operated and the results of elastography were compared with pathological results.
Results: The 34 patients had 99 thyroid nodules that were investigated. 65 nodules were soft in elastography (score 13) and 34 were hard (score 45). At pathological exam all the 65 soft nodules were benign and from the 34 hard nodules 17 were benign and 17 malignant. In 4 patients multiple malignant nodules were found.
Conclusion: Elastography showed a sensitivity of 100% and a specificity of 79% in diagnosing malignant nodules. With a positive predictive value (PPV) of 50% and a negative predictive value (NPV) of 100% it seems more valuable in excluding malignancy than in affirming it.
25 - 29 Apr 2009
European Society of Endocrinology