Utility of the ultrasound elastographic systolic thyroid stiffness index in reducing fine-needle aspirations.
OBJECTIVE
The purpose of this study was to evaluate whether ultrasound elastography performed by using carotid pulsation as a compression source and generating the systolic thyroid stiffness index (STSI) can be used as a pre-fine-needle aspiration (FNA) screening tool.


METHODS
Ultrasound data previously acquired from 62 thyroid nodules in 59 patients who underwent a thyroid FNA were used. Pulsation from the carotid artery was used as the compression source, and the strain was calculated offline. A metric called the STSI was computed for each nodule during systole. On the basis of the derived STSI value, thyroid nodules were retrospectively classified into 2 types: I, no FNA (observation only); and II, FNA.


RESULTS
The STSI value of malignant nodules (n = 12) was significantly higher than that of benign nodules (n = 39; P < .00002). Using an STSI cutoff value of 10, 31 nodules were classified as type I, all of which were benign, whereas 20 nodules were classified as type II, 12 malignant and 8 benign, with sensitivity of 100% and specificity of 79.4%. This suggests that ultrasound elastography could have screened out 31 type I nodules, reducing the number of FNAs by 60.8%.


CONCLUSIONS
Thyroid ultrasound elastography has the potential to substantially reduce the number of FNA biopsies by detecting type I benign nodules. Patients with suspicious type II nodules would be referred for an FNA. Future prospective studies are needed to confirm the efficacy of thyroid ultrasound elastography as a triage tool to FNA.
Dighe
Manjiri
M
Department of Radiology, University of Washington Medical Center, Seattle, WA 98195, USA. dighe@u.washington.edu
Kim
Jae
J
Luo
Si
S
Kim
Yongmin
Y
D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle; D003937:Diagnosis, Differential; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013599:Systole; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology