Evaluation of the thyroid nodule with high-resolution ultrasonography and elastography without fine needle aspiration biopsy.

INTRODUCTION

Fine needle aspiration biopsy (FNAB) is the gold standard screening technique used in the diagnostic protocol for thyroid nodules. However, it is not free of complications.

OBJECTIVE

To identify thyroid nodules in which FNAB could be avoided during the diagnostic process by means of the use of a high-resolution ultrasonography or elastography.

MATERIAL AND METHOD

A prospective, non-randomized study was carried out. Single thyroid nodules and dominant nodules of multinodular goiter were included. Patients who had undergone thyroid surgery in the past were excluded. All patients underwent a high-resolution ultrasound and elastography, and, subsequently, a FNAB. We analyzed the ultrasound variables in 2D and Doppler, followed by the elastographic variables, and the results of the FNAB according to Bethesda. To correlate the data, the nodules were classified as benign or malignant. Student's t test, the Chi-square test and a logistic regression analysis were applied for the statistical analysis.

RESULTS

A total of 221 thyroid nodules were analyzed, 32 of which were malignant (14%). The most predictive ultrasound findings of malignancy (P<.05) were a hypoechoic or complex echostructure (OR=11.832), the presence of microcalcifications (OR=9.637) and chaotic vascularization observed in the Doppler (OR=46.464). With regard to the elastography, elastographic patterns i and ii were seen to be associated with benignity (P=.0004 and P<.0001, respectively). When type i or ii elastography was combined with an ultrasound showing a non-hypoechoic nor complex echostructure, without microcalcifications nor chaotic vascularization in the Doppler ultrasound, 100% of the cases were benign with a specificity of 100% and a sensitivity of 14%.

CONCLUSIONS

The combination of a high-resolution ultrasound with an elastography makes it possible to select cases where a FNAB does not have to be performed. Cases susceptible to a periodic follow-up without the use of a FNAB are those without a hypoechoic nor complex structure, no microcalcifications, non-chaotic vascularization and a type i or ii elastography.