Utility of contrast-enhanced ultrasound for evaluation of thyroid nodules.
BACKGROUND
No conventional imaging method reliably distinguishes between benign and malignant thyroid nodules. Our objectives were to characterize the enhancement patterns of thyroid nodules on gray-scale contrast-enhanced ultrasound (US) and to evaluate whether these patterns were useful in the differential diagnosis of thyroid nodules.


METHODS
Ninety-five patients, scheduled for surgery for thyroid nodules detected by gray-scale sonography, were enrolled in this prospective study. In all, there were 104 nodules (47 papillary carcinomas, 3 medullary carcinomas, 1 metastatic carcinoma, 44 hyperplasia nodule, 7 follicular adenomas, 1 suture granulomas, and 1 Hashimoto's disease). After intraveneous (i.v.) injection of a 1.2 mL bolus of SonoVue, lesions were scanned with real-time gray-scale pulse inversion harmonic imaging US for at least 3 minutes at low mechanical index (MI) (0.05 to 0.08). The enhancement patterns were classified into one of four patterns by two experienced readers.


RESULTS
After administration of SonoVue, four enhancement patterns (homogeneous, heterogeneous, ring-enhancing, and no enhancement) were observed. Four benign and 3 malignant nodules had homogeneous enhancement pattern, 4 benign and 45 malignant nodules had heterogeneous enhancement, 44 benign and 3 malignant nodules had ring enhancement, and 1 benign nodule had no enhancement. There was a significant difference between benign and malignant nodules (p < 0.001). The benign thyroid nodules showed four enhancement patterns: ring enhancement 44/53 (83.0%), homogeneous enhancement 4/53 (7.5%), heterogeneous enhancement 4/53 (7.5%), and no enhancement 1/44 (1.9%). The malignant thyroid nodules showed three enhancement patterns: heterogeneous enhancement 45/51 (88.2%), ring enhancement 3/51 (5.9%), and homogeneous enhancement 3/51 (5.9%). Ring enhancement correlated highly with a benign diagnosis (sensitivity 83.0%, specificity 94.1%, positive predictive value 93.6%, negative predictive value 84.2%, and accuracy 88.5%). Heterogeneous enhancement correlated highly with a malignant diagnosis (sensitivity 88.2%, specificity, 92.5% positive predictive value 91.8%, negative predictive value 89.1%, and accuracy 90.4%). In both mixed and solid nodules, ring enhancement was highly predictive of a benign finding, whereas heterogeneous enhancement was highly predictive of a malignant finding.


CONCLUSIONS
Contrast-enhanced US enhancement patterns were different in benign and malignant lesions. Ring enhancement was predictive of benign lesions, whereas heterogeneous enhancement was helpful for detecting malignant lesions.
Zhang
Bo
B
Department of Diagnostic Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
Jiang
Yu-Xin
YX
Liu
Ji-Bin
JB
Yang
Meng
M
Dai
Qing
Q
Zhu
Qing-Li
QL
Gao
Pin
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002291:Carcinoma, Papillary / Q000175:diagnosis / Q000473:pathology; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006965:Hyperplasia / Q000175:diagnosis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010743:Phospholipids; D011237:Predictive Value of Tests; D013459:Sulfur Hexafluoride; D013961:Thyroid Gland / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D018615:Ultrasonography, Doppler, Color / Q000379:methods; D018617:Ultrasonography, Doppler, Pulsed / Q000379:methods*; D055815:Young Adult
D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride