Can Color Doppler Sonography Aid in the Prediction of Malignancy of Thyroid Nodules?

Abstract

OBJECTIVE: To determine whether color Doppler interrogation of a thyroid nodule can aid in the prediction of malignancy. METHODS: We obtained color Doppler images of thyroid nodules undergoing sonographically guided fine-needle aspiration. The color Doppler appearance of each nodule was graded from 0 for no visible flow through 4 for extensive internal flow. The size, sonographic appearance, results of fine-needle aspiration, and surgical pathologic findings, if available, were recorded for each nodule. RESULTS: There were 254 nodules sampled, of which 32 were malignant (all confirmed at surgery) and 177 were benign. Fourteen (43.8%) of the 32 malignant nodules were color type 4, compared with only 26 (14.7%) of the 177 benign nodules (P = .0004, Fisher exact test). Thirteen (40.1%) of the 32 malignant nodules were solid, as were 18 (10.2%) of the 177 benign nodules (P = .006, Fisher exact test). Among solid nodules, the prevalence of malignancy was greater when the nodule was hypervascular (13 [41.9%] of 31) than when the color type was less than 4 (11 [14.7%] of 77; P = .004, Fisher exact test). CONCLUSIONS: Solid hypervascular thyroid nodules have a high likelihood of malignancy (nearly 42% in our series). The color characteristics of a thyroid nodule, however, cannot be used to exclude malignancy, because 14% of solid nonhypervascular nodules were malignant.