Real-time ultrasound elastography--a noninvasive diagnostic procedure for evaluating dominant thyroid nodules

Abstract

Purpose: Ultrasound elastography (USE) is a newly developed technique for the evaluation of tissue stiffness. It is known that malignancies often show a low-strain value. So far, only limited data for thyroid nodules is available.

Methods: This study included 309 prospective evaluated patients with dominant, nontoxic thyroid nodules. All patients were referred to surgery. USE was performed preoperatively. Three measuring groups were formed: hard (< 0.15), intermediate (0.16-0.3), and soft (> 0.31). The measurements were correlated to the final histological findings.

Results: The strain rated from 0.01 to 0.84 (mean 0.26 ± 0.13). A total of 50 thyroid malignancies (35 papillara carcinoma, 9 medullary carcinoma, and 6 follicular carcinoma) were observed. Patients (81) were within the hard group, 35 of them (43.2%) had thyroid cancer (TC) in final histology. Out of 132 patients in the intermediate group, 15 patients had TC (11.4%). All 96 patients from the soft group showed benign histological results (NPV 100%). Seventy percent of patients with TC were within the hard group (PPV 42%). These results were highly significant (p < 0.001). Coarse calcifications and cystic nodules were not connected with reliable measurements and therefore are not suitable for USE.

Conclusion: USE is a useful adjunctive tool in the workup of thyroid nodules. A low strain value needs surgical intervention, whereas a high strain value predicts a benign histology. It might substitute fine-needle aspiration cytology in the future.