Nodule size is a key factor for differentiating benign and malignant thyroid nodules using virtual touch tissue quantification and conventional sonography

Thyroid nodules with different size may have different ultrasound features. We compared the differences of ultrasound features of small and large thyroid nodules and figured out the best features for small and large nodules for the differential diagnosis. 348 thyroid nodules included in this study were divided into four groups as small malignant nodules, small benign nodules, large malignant nodules and large benign nodules. The conventional sonographic features and quantitative elasticity features (VTQ, Virtual Touch Tissue Quantification and VTR, ratio of VTQ value of the nodule to that of the surrounding thyroid tissue) were observed and compared among the four groups. When compared with large malignant nodules, small malignant nodules were less frequently solitary, with macrocalcification, more frequently "taller than wide" and had lower VTQ and VTR. The most sensitive features for large nodules were with higher VTR and a solitary occurrence and those for small nodules were with higher VTQ, a taller than wide shape and marked hypoechogenicity. In conclusion, malignant thyroid nodules with different size had different conventional sonographic features and elastic features, which should be taken consideration during the differential diagnosis.