To explore the value of high frequency ultrasound in differential diagnosis in dorsal thyroid(including gland dorsal or posterior) nodules.

Ultrasonographic features of 101 patients with ultrasonography suspected or misdiagnosed nodules in the dorsal area of the thyroid gland, which were then confirmed by pathology or hyaluronography/gastroscopy, were retrospectively analyzed. Ultrasonographic homogeneity (other nodules with similar ultrasonographic features were found in the ipsilateral gland), parenchyma homology (nodule parenchyma was continuous with glandular parenchyma) and blood homology (blood flow signals in nodules were continuous with those in glandular parenchyma) were applied as indicators for determinng thyroid nodules. Double-line sign or vascular arch sign at the edge of nodules served as an indicator for determining parathyroid nodules.

Of the 101 cases, there were 46 thyroid nodules, 35 parathyroid nodules, 7 enlarged lymph nodes; 6 esophageal diverticulum, 6 esophageal cancer, 1 cleft cyst.The determination of thyroid nodules by at least one of ultrasonographic homogeneity, parenchyma homology and blood homology showed sensitivity of 73.5%, specificity of 96.5% and accuracy of 85.8%. In the determination of parathyroid nodules by double-line sign or vascular arch sign at the edge of nodules, sensitivity, specificity and accuracy was 54.1%, 85.5% and 74.5%, respectively.

Nodules in the dorsal area of the thyroid gland have different sources, and the understanding of corresponding characteristic ultrasonographic appearances is helpful for improving the differential diagnosis of these nodules.

Ultrasonography; Thyroid nodule; Parathyroid diseases