The importance of compression elastography in the evaluation of thyroid nodule malignancy

Abstract

Introduction/Objective Compression, also called strain elastography imaging techniques, represent new echotomographic modality, which is a promising method for the differentiation of benign from malignant lesions, not only in the thyroid gland but also in other organs. The objective of this study is to evaluate the importance of compression elastography in the differentiation of benign and malignant thyroid nodules.

Methods We performed echotomographic examinations in B mode, and examinations using compression elastography in a total of 186 persons (152 females and 34 males, with the average age of 45.3 ± 13.5 years), with 264 nodules in the thyroid gland. Elastography was done in two steps: the first one through scoring elastographic figures, and the second one through the determination of the resistance index (strain ratio – SR).

Results Using elastography scores by Fukunari, 44 of 60 malignant nodules had a score of 3–4, while 152 of the 204 benign nodules had a score of 1–2. Using the receiver operating characteristic (ROC) analysis, the best cut-off point obtained using elastography scores was 2, with a sensitivity of 73.3% and specificity of 74.5%. Using the software-calculated SR we found that out of 89 nodules with SR ≥ 2.5, 52 were malignant nodules, while out of 175 nodules with SR < 2.5, 167 were benign nodules. Using the ROC analysis, the best cut-off point obtained using SR was > 2.5, with a sensitivity of 86.7%, and specificity of 81.9%.

Conclusion As a follow-up of standard echotomographic examination in B mode, compression elastography is a newly developed and promising technique in the differentiation of benign from malignant lesions.

Keywords: compression elastography; nodule; thyroid gland; malignancy