The use of ultrasound elastography in the assessment of malignancy risk in thyroid nodules and multinodular goitres.

OBJECTIVE

The objective of our work is to use a surgical series to analyse the validity of elastography in evaluating the malignancy of thyroid nodules and multinodular goitres.

PATIENTS AND METHODS

The study examined 156 patients, 134 women (85·9%) and 22 men (14·1%), who underwent surgery for nodular thyroid disease between October 2008, and November 2010. The average age of the patients was 52 years (±14·42). Thirty-six patients (23·1%) presented with a single nodule, and 120 (76·9%) exhibited multinodular goitres. Prior to surgical intervention, all patients underwent colour eco-elastography using a qualitative five-point ordinal scale for nodule classifications. Test results were analysed using a receiver operating characteristic (ROC) curve, and an anatomical pathologic examination of surgical specimens was used as a gold standard diagnostic tool for comparison.

RESULTS

Of the 192 nodules analysed, 28 (14·6%) were malignant. Using elastography data, an ROC curve was obtained with an area under the curve of 0·662 (±0·060) and a 95% confidence interval (CI 95%) between 0·545 and 0·779 (P = 0·006). By establishing a cut-off point that classified thyroid nodules with an elastographic value greater than or equal to 3 as malignant, we achieved a sensitivity of 75%, specificity of 45·73%, positive predictive value of 19·1% and negative predictive value of 91%. The positive and negative likelihood ratios were 1·38 and 0·55, respectively.

CONCLUSIONS

Ultrasound elastography can provide information regarding malignancy risk in thyroid nodules and multinodular goitres. However, the sensitivity and specificity values obtained in our study are below those reported by other groups, a finding that calls into question the current clinical utility of ultrasound elastography.